Feasibility of Angiographic CT in Peri-Interventional Diagnostic Imaging: A Comparative Study with Multidetector CT • M.-N. Psychogios, J.-H. Buhk, P. Schramm, A. Xyda, A. Mohr, and M. Knauth
Today, many interventional neuroradiologists work with angiographic equipment that is also capable of obtaining CT images, clearly something advantageous when hemorrhages or other complications are suspected during or immediately after a procedure. In this study, the authors compared the results of angiographic CT with those of multidetector CT in 84 patients (postaneurysm coiling, -thrombectomy, or -angioplasty with stent deployment). Both CT methods rated equally in the detection of supratentorial complications (such as hemorrhage) but MDCT was clearly superior in the evaluation of posterior fossa complications when compared with ACT. The authors concluded ACT is very useful except in the evaluation of cerebellar infarctions.

Higher Rates of Mortality but Not Morbidity Follow Intracranial Mechanical Thrombectomy in the Elderly • Y. Loh, D. Kim, Z.-S. Shi, S. Tateshima, P.M. Vespa, N.R. Gonzalez, S. Starkman, J.L. Saver, R. Jahan, D.S. Liebeskind, G.R. Duckwiler, and F. Viñuela
In this article, the authors compared thrombectomy performed using the Merci device in patients younger and older than 80 years to determine the influence of age on procedure outcome (something of significant importance as our patient population ages). They looked at the following parameters in both patient groups: recanalization rates, hospital length of stay, hemorrhagic transformation, death, and disability on discharge. The only difference in these parameters was death rate, which was more common in the elderly (48% vs 15%); the other parameters showed no differences between groups. This important observation needs to be kept in mind when performing thrombectomy in patients of advanced age.

Wallerian Degeneration in the Corticospinal Tract Evaluated by Diffusion Tensor Imaging Correlates with Motor Deficit 30 Days after Middle Cerebral Artery Ischemic Stroke • J. Puig, S. Pedraza, G. Blasco, J. Daunis-i-Estadella, A. Prats, F. Prados, I. Boada, M. Castellanos, J. Sánchez-González, S. Remollo, G. Laguillo, A.M. Quiles, E. Gómez, and J. Serena
Wallerian degeneration is not uncommon after middle cerebral artery infarctions and portends a worse prognosis if present. These authors used diffusion tensor imaging (and fractional anisotropy measurements) as well as signal changes on conventional MR images to assess WD after MCA infarctions. Sixty patients were evaluated within 12 hours of infarct onset, at 3 days, and at 30 days. All results were compared with ratings according to the NIHSS scale. At day 30, FA in the ipsilateral corticospinal tract was significantly lower when compared with the unaffected side. This finding also correlated strongly with the presence of significant motor deficit. The authors suggest that FA at 30 days postinfarct may serve as a surrogate marker in future stroke studies.

Fellows’ Journal Club

Imaging Characteristics of Primary Laryngeal Lymphoma • N.A. Siddiqui, B.F. Branstetter IV, B.E. Hamilton, L.E. Ginsberg, C.M. Glastonbury, H.R. Harnsberger, E.L. Barnes, and E.N. Myers
The larynx is a very rare site for primary lymphoma with less than 100 cases reported in the literature. Here, the authors report the MR, CT, and positron-emission tomography features in 20 such cases. The patients’ ages (30–90 years) varied but this finding was more common in women. At presentation, the tumors were large (4 cm) and tended to begin in the supraglottic region but variably extended into both the infraglottic and hypopharyngeal areas in about 60% of patients. Cartilage invasion and lymph nodes were positive in 20% of patients and all tumors showed uptake on PET. No tumors displayed central necrosis and all enhanced uniformly. Although these tumors are rare, this combination of findings may suggest the diagnosis.

Artery of Percheron Infarction: Imaging Patterns and Clinical Spectrum • N.A. Lazzaro, B. Wright, M. Castillo, N.J. Fischbein, C.M. Glastonbury, P.G. Hildenbrand, R.H. Wiggins, E.P. Quigley, and A.G. Osborn
Some years ago, I wrote a short case report on this topic and since then it has been part of AJNR’s Most Read list. You can think about this article as the Rolls Royce version of that earlier manuscript. The authors collected data on 37 patients with occlusion of the artery of Percheron seen during a 9-year period. The most common ischemic patterns observed involved the medial thalami and midbrain, medial thalami without the midbrain, both of these sites plus the anterior thalami, and medial and anterior thalami without the midbrain. Additionally, fluid-attenuated inversion recovery hyperintensity on the surfaces of the interpeduncular cistern was present in nearly nearly two-thirds of patients and this new sign may be used to support the diagnosis of occlusion of the artery of Percheron. Recognition of this sign may help manage patients, as this type of infarction should not be considered lacunar. NB: I am a co-author of this article but that is not the reason why I selected it as a Fellows’ Journal Club choice!

The Triple Rule-Out for Acute Ischemic Stroke: Imaging the Brain, Carotid Arteries, Aorta, and Heart • A.D. Furtado, D.D. Adraktas, N. Brasic, S.-C. Cheng, K. Ordovas, W.S. Smith, M.R. Lewin, K. Chun, J.D. Chien, S. Schaeffer, and M. Wintermark
In this study, the authors sought to assess the utility of a comprehensive imaging protocol for stroke patients aimed at evaluating the heart chambers and coronary arteries, the circle of Willis, the aorta, and the carotid arteries. Stroke patients in whom these common embologenic sites are diseased carry a worse prognosis. The protocol was used to evaluate 120 patients. With regard to quality, 100% of the studies of the aorta, carotid, and vertebral arteries were of excellent quality whereas 58–73% of coronary artery studies were judged as good. The authors concluded their stroke protocol achieved excellent opacification of the left heart chambers, the cervical arteries, and each coronary artery, in addition to adequate carotid and coronary artery image quality.

Apparent Diffusion Coefficient of Glial Neoplasms: Correlation with Fluorodeoxyglucose–Positron-Emission Tomography and Gadolinium-Enhanced MR Imaging • A.I. Holodny, S. Makeyev, B.J. Beattie, S. Riad, and R.G. Blasberg
The authors state that contrast enhancement does not always correlate with tumor histology and thus they compared the findings of FDG-PET and apparent diffusion coefficient maps to postcontrast MR images in 21 patients with cerebral glial neoplasias. All images were subjectively and objectively evaluated and correlation coefficients calculated for all regions of interest analyzed. Subjective evaluation showed a 60% correlation between PET and ADC with a greater overlap between PET and ADC than with contrast enhancement. ADC better correlated with survival (for more on this, listen to Dr. Cha’s podcast, April 2010). The authors concluded that ADC provided analogous information to PET when compared to gadolinium.

Simultaneous Bilateral Carotid Stenting in High-Risk Patients • S. Liu, J.H. Jung, S.-M. Kim, H.-K. Lim, H.-j. Kwon, J.K. Kim, J.S. Kim, and D.C. Suh
Here, the authors evaluated the results of bilateral carotid artery stenting in 30 consecutive patients. The procedure was simultaneous in 24 and staged in 6 patients. A group of 175 patients undergoing unilateral carotid stenting was used as controls. Outcomes at 30 days and 6 months were compared. Postprocedure hyperperfusion syndrome was more common after bilateral stenting, but there were no differences at 6 months between groups in minor or major strokes, re-stenosis, or death.

Similar Safety in Centers with Low and High Volumes of Endovascular Treatments for Unruptured Intracranial Aneurysms: Evaluation of the Analysis of Treatment by Endovascular Approach of Nonruptured Aneurysms Study • L. Pierot, L. Spelle, F. Vitry, for the ATENA Investigators
Do experienced interventionalists have better patient outcomes than those with lesser experience? These French authors selected 649 patients from the ATENA database and evaluated the results of aneurysm coilings in centers that had treated <20 aneurysms vs those centers that had treated >21 aneurysms. Stent-assisted procedures were performed more often in experienced centers, thromboembolic events and intraprocedural ruptures were more common in less experienced centers, but mortality and morbidity rates 1 month postprocedure as well as anatomic results were not different between the 2 groups of operators.

Fellows’ Journal Club

Diagnostic Yield of Double-Dose Gadobutrol in the Detection of Brain Metastasis: Intraindividual Comparison with Double-Dose Gadopentetate Dimeglumine • E.S. Kim, J.H. Chang, H.S. Choi, J. Kim, and S.-K. Lee
It seems that everything goes in circles! Many years ago we published a number of articles dealing with the benefits of double doses of MR imaging contrast agents. In a variation of the theme, these authors looked at the efficacy of double-dose gadobutrol vs double-dose gadopentetate dimeglumine in 27 patients who underwent gamma knife treatment of brain metastases. They counted the lesions and measured contrast-to-noise ratios. Gadobutrol was better, identifying 25 additional lesions and not missing any that were seen with gadopentetate. CNRs were also higher with gadobutrol. Because gadobutrol is safe in patients with renal impairment and has not been associated with systemic nephrogenic fibrosis, the authors concluded that double-dosing these specific patients is best.

Inter- and Intraobserver Agreement in CT Characterization of Nonaneurysmal Perimesencephalic Subarachnoid Hemorrhage • W. Brinjikji, D.F. Kallmes, J.B. White, G. Lanzino, J.M. Morris, and H.J Cloft
This is a topic of importance because the definition of perimesencephalic subarachnoid hemorrhage and its interpretation varies among individuals, and results in different work-ups. The authors retrospectively reviewed CT images in 37 patients with PM SAH in whom aneurysms had been excluded previously by digital subtraction angiography. In 78% of instances, the 4 readers agreed unanimously and they disagreed in 22% of cases. Intra- and interobserver agreements were considered good. Because there was disagreement, the authors suggest caution in interpreting this pattern of SAH and when deciding to pursue additional follow-up studies in such patients.

Dose Exposure of Patients Undergoing Comprehensive Stroke Imaging by Multidetector-Row CT: Comparison of 320-Detector Row and 64-Detector Row CT Scanners • S. Diekmann, E. Siebert, R. Juran, M. Roll, W. Deeg, H.-C. Bauknecht, F. Diekmann, R. Klingebiel, and G. Bohner
More CT detectors implies better coverage (with 320 detectors you can scan the entire brain) and higher quality studies, but these days we all are very concerned with radiation exposure. Using phantoms, exposures were measured for different body regions and effective doses were then calculated for the following different studies: head CT, CT angiography of the head and the neck, and CT perfusion. When compared to 64-detector CT, 320-detector CT delivered nearly 25% more radiation. Critical doses that would cause organ damage were not reached, but caution is advised and weighing risk vs benefit is important when using higher detector CT units.

A Prospective Trial of 3T and 1.5T Time-of-Flight and Contrast-Enhanced MR Angiography in the Follow-up of Coiled Intracranial Aneurysms • T.J. Kaufmann, J. Huston III, H.J. Cloft, J. Mandrekar, L. Gray, M.A. Bernstein, J.L. Atkinson, and D.F. Kallmes
Other past articles have dealt with comparisons between DSA and contrast enhanced MRA for detection of residual post treatment aneurysms. This article deals with a similar topic but addresses the question of which is better for MRA in this situation: 1.5T or 3.0T? The authors prospectively studied 63 coiled aneurysms within one week of obtaining DSA in them all. The non-invasive imaging included TOF MRA and CE-MRA at 1.5T and 3.0T (4 studies per patient). Regardless of the type of aneurysm remnant the sensitivity of MRA varied between 85-90%. However, CE-MRA was better for aneurysms with larger remnants. The authors concluded that both TOF and CE MRA should be obtained for the follow-up of post-coiled aneurysms.

Comparison of the Added Value of Contrast-Enhanced 3D Fluid-Attenuated Inversion Recovery and Magnetization-Prepared Rapid Acquisition of Gradient Echo Sequences in Relation to Conventional Postcontrast T1-Weighted Images for the Evaluation of Leptomeningeal Diseases at 3T • H. Fukuoka, T. Hirai, T. Okuda, Y. Shigematsu, A. Sasao, E. Kimura, T. Hirano, S. Yano, R. Murakami, and Y. Yamashita
Are there better sequences to use after Gd administration other than just the conventional T1-weighted images? Here the investigators compared post Gd 3D FLAIR and MPRAGE with T1WI. 12 patients with known leptomeningeal disease underwent all 3 sequences, which were thereafter subjectively evaluated. Also, the in vitro effect of different Gd concentrations on the FLAIR images was assessed. Results: in vivo and in vitro post Gd FLAIR images were better than MPRAGE or T1W ones.

Recanalization Rates Decrease with Increasing Thrombectomy Attempts • Y. Loh, R. Jahan, D.L. McArthur, Z.-S. Shi, N.R. Gonzalez, G.R. Duckwiler, P.M. Vespa, S. Starkman, J.L. Saver, S. Tateshima, D.S. Liebeskind, and F. Viñuela
If one uses the MERCI system to retrieve a clot, what is the optimum number of times one should try and after how many attempts does the possibility of success decline? To answer these questions the authors looked at 115 arterial occlusions (including ICA, MCA and vertebrobasilar ones). The average number of attempts was 3, and they also concluded that 3 is the optimum number of attempts. After 4 attempts the results more often included failed recanalizations and procedural complications.

Fellows’ Journal club

Adult Lumbar Scoliosis: Underreported on Lumbar MR Scans • Z. Anwar, E. Zan, S.K. Gujar, D.M. Sciubba, L.H. Riley III, Z.L. Gokaslan, and D.M. Yousem
It seems to me that all of us report scoliosis when we see it, but this article proves me wrong! The authors did a retrospective review of nearly 1300 spine MRI studies, assessed them for presence of scoliosis and also measured it. They found that scoliosis was present in 20% of studies with higher rates in females and those over 60 years of age. Scoliosis went unreported in 67% of cases particularly when the angle was less than 20 degrees. Spondylolisthesis was present in 15% of scoliosis patients and was reported in nearly all instances. Remember that scoliosis may be the cause of back pain in adults, and thus, it is important to mention it in our reports.

Attenuation of Cerebral Venous Contrast in Susceptibility-Weighted Imaging of Spontaneously Breathing Pediatric Patients Sedated with Propofol • J. Sedlacik, U. Löbel, M. Kocak, R.B. Loeffler, J.R. Reichenbach, A. Broniscer, Z. Patay, and C.M. Hillenbrand
We are using SWI more and more each day so it behooves us to be aware of artifacts and limitations associated with it. Since most children are sedated for MRI studies and the sedation changes cerebral hemodynamics, the authors hypothetized that sedation would also affect SWI. They went back and classified venous contrast as weak or strong in 125 SWI studies obtained under sedation. They also monitored some physiologic parameters and the cerebral blood flow with ASL perfusion. Venous contrast on SWI correlated with CBF and CO2 in the following way: when both were high, venous contrast was weak and when both were low, venous contrast was strong. Also, patients with high blood pressure showed strong SWI contrast. Thus, it is important to remember that venous contrast on SWI may be affected in sedated patients.

Functional Contrast-Enhanced CT For Evaluation of Acute Ischemic Stroke Does Not Increase the Risk of Contrast-Induced Nephropathy • F.O. Lima, M.H. Lev, R.A. Levy, G.S. Silva, M. Ebril, É.C. de Camargo, S. Pomerantz, A.B. Singhal, D.M. Greer, H. Ay, R. Gilberto González, W.J. Koroshetz, W.S. Smith, and K.L. Furie
This article is included in our new “Patient Safety” category, and therefore, I thought it prudent to list here since fellows and residents are usually the ones determining the protocols for studies. Patients with suspected stroke get CTA and CT perfusion studies and thus larger doses of iodinated contrast. The authors sought out to determine if this resulted in nephropathy (defined as a 25% increase in creatinine when compared to pre-CT levels). They assessed Cr levels in 575 patients who underwent CTA, CTA/CTP or CTA/CTP + DSA and used as controls 343 acute stroke patients who received no contrast. The incidence of nephropathy was 5% in those who received contrast vs. 10% in those who did not. DSA after CTA/CTP did not increase risk of nephropathy, and the authors concluded that doing DSA after dosing the patient for CTA/CTP is well tolerated.

Utility of the K-Means Clustering Algorithm in Differentiating Apparent Diffusion Coefficient Values of Benign and Malignant Neck Pathologies• A. Srinivasan, C.J. Galbán, T.D. Johnson, T.L. Chenevert, B.D. Ross, and S.K. Mukherji
What is K-means clustering? It is a statistical technique that allows one to cluster or classify objects according to a common trait. In this study, the authors used this technique in an attempt to classify neck lesions as either benign or malignant according to their ADC values. The reason for this: using isolated ADC values for this same purpose is fraught with difficulty and not always reliable. They retrospectively assessed 10 benign and 10 malignant neck lesions and clustered them into a 2-partition (low and high ADC) or a 3-partition (low, intermediate, and high ADC) model. Results: statistically significant differences were found for benign vs. malignant lesions in both partition models and were also predictive of malignancy. They conclude that clustering of large datasets provides a better characterization of neck lesions when compared to whole-lesion ADC alone.

A Novel Association between RASA1 Mutations and Spinal Arteriovenous Anomalies• R. Thiex, J.B. Mulliken, N. Revencu, L.M. Boon, P.E. Burrows, M. Cordisco, Y. Dwight, E.R. Smith, M. Vikkula, and D.B. Orbach
This wonderful article is destined to become a classic. The association of capillary vascular malformations and spine AVM and/or AVF is newly recognized and due to mutations in the RASA 1 gene located in a long arm of chromosome 5. This new syndrome is called CM-AVM. This gene partly controls vascular cellular proliferation and differentiation. The authors found 5 patients with skin and spine metameric lesions and investigated them for the gene mutation, which they all had. This is the first report of this association, and the authors speculate that similar genetic abnormalities may be responsible for other metameric spinal and cerebral vascular conditions.

Penumbra System: A Novel Mechanical Thrombectomy Device for Large-Vessel Occlusions in Acute Stroke • Z. Kulcsár, C. Bonvin, V.M. Pereira, S. Altrichter, H. Yilmaz, K.O. Lovblad, R. Sztajzel, and D.A. Rüfenacht
Although the Penumbra clot-retrieval device is approved for intracranial use, the authors of this investigation set out to evaluate if it can be used for recanalization of large internal carotid artery occlusions. 27 patients underwent isolated thrombectomy or thrombectomy in combination with pharmacological clot lysis and stent placement. The goals of treatment were improvement of the stenosis, NIHSS grade and outcome. 23 patients had anterior circulation occlusions, and the basilar artery was involved in 4. Adequate recanalization was accomplished in 93% of patients while over 50% of patients showed clinical improvement at discharge. Complete recanalization correlated with favorable outcome and overall mortality was 11%. Conclusion: the Penumbra system shows high potential for recanalization of large arteries.

Fellows’ Journal Club

Negative CT Angiography Findings in Patients with Spontaneous Subarachnoid Hemorrhage: When Is Digital Subtraction Angiography Still Needed? • R. Agid, T. Andersson, H. Almqvist, R.A. Willinsky, S.-K. Lee, K.G. terBrugge, R.I. Farb, and M. Söderman
About 20% of patients with SAH will show no demonstrable underlying cause by catheter angiography. Can CTA be used to exclude an underlying aneurysm instead of conventional angiography? The authors retrospectively identified 193 patients with SAH and negative CTA who also underwent catheter angiograms. They correlated the location of the SAH with findings on CTA and DSA. Acutely only 1 patient had an aneurysm not seen on CTA while on repeat angiography 4 such cases were identified. Five patients, however, experienced complications from DSA. A common cause of SAH with negative CTA was vasculitis. The authors concluded that initial negative CTA findings are reliable in ruling out aneurysm in patients with SAH isolated to the perimesencephalic region but that DSA continues to be needed in patients with initially negative CTA but diffuse SAH. Vasculitis was associated with peripheral SAH.

Optimal Brain Perfusion CT Coverage in Patients with Acute Middle Cerebral Artery Stroke • A.D. Furtado, B.C. Lau, E. Vittinghoff, W.P. Dillon, W.S. Smith, T. Rigby, L. Boussel, and M. Wintermark
More and more institutions rely on CT perfusion instead of MR perfusion due to its ease of access. The extent of brain coverage with some CT units is still limited, and the authors undertook this study to determine the amount of coverage needed to estimate the size of MCA infarctions and the core-penumbra mismatch. 50 acute stroke patients underwent CT perfusion with 16×5 mm slices, and its accuracy and impact were studied. All patients had follow-up studies 3 days to 3 months later. The authors concluded that to determine mismatch and select patients for treatment, coverage of 75 mm is needed, and 50 mm coverage is needed to assess the core infarct. Thus, older CT units that give you only 3 perfusion slices may not be the best to use.

Utility of CT Angiography in the Identification and Characterization of Supraclinoid Internal Carotid Artery Blister Aneurysms • J.R. Gaughen Jr, P. Raghavan, M.E. Jensen, D. Hasan, A.N. Pfeffer, and A.J. Evans
How can those folks from UVA see so many blood-blister like aneurysms when many of us almost never see one? These aneurysms are very rare, but when they bleed the resulting morbidity and mortality are very high. They are difficult to diagnose even with DSA, but these authors evaluated the utility of CTA in their identification and characterization. In a 12-month period they found 6 such patients who underwent CTA and DSA. All patients had SAH and all aneurysms were seen on DSA (gold standard) while only 4 were initially seen on CTA. Therefore, they concluded that if CTA is negative, DSA is still needed to exclude this rare type of aneurysm.

Occurrence and Predictors of Futile Recanalization Following Endovascular Treatment among Patients with Acute Ischemic Stroke: A Multicenter Study • H.M. Hussein, A.L. Georgiadis, G. Vazquez, J.T. Miley, M.Z. Memon, Y.M. Mohammad, G.A. Christoforidis, N. Tariq, and A.I. Qureshi
Despite the fact that arterial recanalization is the principal goal of endovascular treatment in acute stroke patients many fail to get clinically better. Why? This is the question addressed by these investigators who basically analyzed the existing literature in this topic. Patients received pharmacological and/or mechanical thrombectomies. The authors tried to establish the cause of poor clinical outcome despite complete angiographic recanalization. Nearly 1/3 of patients underwent IA thrombolysis and recanalization, and their results were fruitless in one half of them. Factors associated with futile recanalization included older age, involvement of the basilar artery, higher median NIHSS scores and hemorrhage. Of these, those factors that were statistically significant included older age and lower initial NIHSS scores (severe neurological symptoms).

Late Adverse Events in Coiled Ruptured Aneurysms with Incomplete Occlusion at 6-Month Angiographic Follow-Up • S.P. Ferns, C.B.L.M. Majoie, M. Sluzewski, and W.J. van Rooij
Late complications of aneurysm coil embolization include rebleeding, complications of diagnostic angiography, and progressive mass effect from lesion growth. The authors restrospectively looked at over 900 coiled aneurysms at their 6-month follow-up. Of these, 124 were incompletely occluded and 71% were retreated. They did over 300 diagnostic follow-up angiograms without complications. Four aneurysms rebelled (2 patients died) and 4 regrew (1 died) giving complication annual rates as follows: overall events (1.9%), mortality (0.7%) and rebleeding (1.0%). The authors concluded that angiographic follow-up and recoiling can be done with little harm to the patient and that complications were only related to rebleeding and aneurysm regrowth.

Nonenhancing Intramedullary Astrocytomas and Other MR Imaging Features: A Retrospective Study and Systematic Review • H.S. Seo, J.-h. Kim, D.H. Lee, Y.H. Lee, S.-i. Suh, S.Y. Kim, and D.G. Na
Most of us have been taught that by the time of their discovery all intramedullary tumors show contrast enhancement. The authors did a retrospective review of non-enhancing spinal cord tumors obtained from 4 different institutions. They found 19 patients with cord astrocytomas and analyzed their patterns of contrast enhancement. They found 6 astrocytomas and 2 anaplastic astrocytomas that did not enhance. All other tumors showed some contrast enhancement. They then analyzed the literature and from it concluded that 18% of intramedullary primary tumors do not enhance. Thus, non-enhancing astrocytomas (20-30%) are not rare and should be included in the differential diagnosis of expansile non-enhancing cord masses. This is clearly not my experience, and the findings surprised me.

Diffusely Abnormal White Matter in Progressive Multiple Sclerosis: In Vivo Quantitative MR Imaging Characterization and Comparison between Disease Types • H. Vrenken, A. Seewann, D.L. Knol, C.H. Polman, F. Barkhof, and J.J.G. Geurts
We all know that white matter in MS patients is diffusely affected. Can this diffuse involvement be measured using quantitative MR techniques? Which technique is better for this purpose? In this study, the authors used 4 different techniques (T1 maps, magnetization transfer ratios, ADC and fractional anisotropy) to assess white matter changes and attempted to correlate their results with the type of MS. They found that all four techniques showed abnormal results in the white matter of MS patients. Furthermore, they found that these measurements differ for patients with primary progressive and secondary progressive multiple sclerosis.

Fellows’ Journal Club

Diffusion MR Imaging of Hypoglycemic Encephalopathy • E.G. Kang, S.J. Jeon, S.S. Choi, C.J. Song, and I.K. Yu
Brain imaging findings in adult hypoglycemia are not well established, and here, the authors retrospectively reviewed the MRI features seen in 11 such patients. The areas found to be most severely affected using conventional MR images and DWI (with ADC measurements) were the posterior limbs of the internal capsules, hippocampi, and basal ganglia. In these regions, ADC values were about 50% of normal. In 6 patients the imaging findings resolved and they did well. Patients with cortical or white matter involvement affecting more than one lobe did poorly or died. The lesions that resolved did so very quickly and were probably related to reversible cytotoxic edema.

Cerebral Venous Thrombosis: Diagnostic Accuracy of Combined, Dynamic and Static, Contrast-Enhanced 4D MR Venography • S. Meckel, C. Reisinger, J. Bremerich, D. Damm, M. Wolbers, S. Engelter, K. Scheffler, and S.G. Wetzel
Although cerebral venous thrombosis is probably a common disease, the optimal MR techniques to assess it are uncertain. Here the authors looked at the 39 patients who underwent brain imaging using 4D-MRC, 2D-time-of-flight MRV, gradient echo imaging, T2-weighted sequences. When evaluating thrombosed venous sinuses 4D-MRV did best. For cortical vein thrombosis the best sequences were 4D-MRV and the TOF MRV. The same was true for patients with chronic sinus thrombosis. For isolated cortical vein thrombosis, GRE images were the best. Overall, all modalities did well with specificities ranging from 96-99%. This article contains supplemental movies found online only.

Perfusion CT in Squamous Cell Carcinoma of the Upper Aerodigestive Tract: Long-Term Predictive Value of Baseline Perfusion CT Measurements • S. Bisdas, Z. Rumboldt, K.S. Popovic, M. Baghi, T.S. Koh, T.J. Vogl, and M.G. Mack
These authors sought to find a relationship between perfusion CT results in patients with squamous cell cancers of the head and neck and their survival rates. 84 patients treated with chemoradiation were assessed with maps of blood flow, blood volume, MTT and permeability. Blood volume and permeability were higher in those patients with longer control periods and both parameters were predictive of local tumor control. Thus, higher blood flow and permeability and a mismatch between blood volume and flow predict a good outcome. Please listen to February’s podcast for more information regarding this subject.

Changes in Perfusion CT of Advanced Squamous Cell Carcinoma of the Head and Neck Treated during the Course of Concomitant Chemoradiotherapy • K. Surlan-Popovic, S. Bisdas, Z. Rumboldt, T.S. Koh, and P. Strojan
This is another article from the same group of investigators as the previous one (see above). In this one, the authors looked at similar parameters but in a group (20 patients) with locally advanced head and neck squamous cell cancers, which were treated with chemoradiation. As expected, tumor volumes were reduced regardless of radiation dose in responders. In responders, significant reductions in blood volumes were seen while changes in all other parameters were not significant. It seems that in this group of patients, blood volume maps were better predictors than blood flow and MTT (somewhat different than in their previous study). Thus, CT perfusion results as they relate to prognosis may be different for advanced tumors when compared to more local ones.

Significant Temporal Evolution of Diffusion Anisotropy for Evaluating Early Response to Radiosurgery in Patients with Vestibular Schwannoma: Findings from Functional Diffusion Maps • Y.-C. Lin, C.-C. Wang, Y.-Y. Wai, Y.-L. Wan, S.-H. Ng, Y.-L. Chen, H.-L Liu, and J.-J. Wang
It has been shown that immediately after radiation or chemotherapy, brain tumors (particularly metastases) may have changes in apparent diffusion coefficient, suggesting an alteration of their cellular arrangements that may be related to a better prognosis. Here, the authors evaluated this same concept as it applies to vestibular schwannomas treated with stereotactic radiosurgery. Six patients underwent diffusion tensor and MR imaging after treatment that showed a change in tumor size did not happen until 6 months after irradiation. An initial transient decrease in mean diffusivity and a continuous decrease in fractional anisotropy were observed in all tumors. The authors concluded DTI allows early detection of therapy-induced changes in these tumors and because morphologic changes take some time to become evident, incorporating DTI in their evaluation may be useful. I think this is an interesting observation that will need to be confirmed by a larger series of patients.

Prediction of Response to Chemoradiation Therapy in Squamous Cell Carcinomas of the Head and Neck Using Dynamic Contrast-Enhanced MR Imaging • S. Kim, L.A. Loevner, H. Quon, A. Kilger, E. Sherman, G. Weinstein, A. Chalian, and H. Poptani
This study is somewhat similar to my previous choice in that it looks at the utility of a newer imaging technique (in this case, dynamic contrast-enhanced MR imaging) as it relates to the response of head and neck cancers to therapy. The authors performed DCE-MRI in 33 patients with squamous cell cancers before chemoradiation to see if the results were predictive of response. Patients with complete remission showed a significantly higher K^trans than nonresponders, but no other parameters were found to have significant correlations. The results indicate pretreatment DCE-MRI can potentially predict response of head and neck squamous cell carcinomas to chemoradiation.

Atrophic Enlargement of CSF Volume after Subarachnoid Hemorrhage: Correlation with Neuropsychological Outcome • P. Bendel, T. Koivisto, M. Äikiä, E. Niskanen, M. Könönen, T. Hänninen, and R. Vanninen
Patients with intracranial hemorrhages will undergo subsequent and progressive atrophy of the brain. Does the atrophy correlate with neurologic and cognitive impairments seen in these patients? These investigators performed volumetric MR imaging in 75 such patients 1 year after subarachnoid hemorrhage and correlated their findings with neurocognitive examinations obtained at the same time. They found that presence of hydrocephalus, higher Hunt and Hess grade, higher Fischer grade, and focal parenchymal lesions were associated with enlarged ventricles (the type of treatment was not). They also found enlargement of CSF-containing spaces was significantly associated with neuropsychologic deficits. The fact that the volumes of gray matter were diminished implies the enlargement of the CSF-containing spaces was due to atrophy of the brain.

In Vivo Proton MR Spectroscopy Evaluation of Pyogenic Brain Abscesses: A Report of 194 Cases • D. Pal, A. Bhattacharyya, M. Husain, K.N. Prasad, C.M. Pandey, and R.K. Gupta
Although most of us are familiar with the utility of MR spectroscopy in the evaluation of brain abscess and its findings, I have included this article because of its very large number of cases. The authors retrospectively re-evaluated MRS studies obtained at 1.5T in 194 patients with proven pyogenic brain abscesses. Amino acids were observed in 80% of abscesses. Obligate anaerobes showed lipids, lactate, and amino acids whereas most obligate aerobes show lactate and amino acids but no lipids. The authors concluded that though most pyogenic brain abscesses show amino acids, some do not, and the presence of acetate with or without succinate favors an anaerobic bacterial origin, but this finding is also not completely reliable. Because we never interpret MRS isolated from MR imaging, this study confirms MRS is useful as an adjunct when a brain abscess is suspected.

FELLOWS’ JOURNAL CLUB

Contrast-Enhancement of the Anterior Eye Segment in Patients with Retinoblastoma: Correlation between Clinical, MR Imaging, and Histopathologic Findings • P. de Graaf, P. van der Valk, A.C. Moll, S.M. Imhof, A.Y.N. Schouten-van Meeteren, D.L. Knol, and J.A. Castelijns
We have all been taught to look behind the orbit in patients with retinoblastoma because this tumor not uncommonly extends there and this finding predicts a poorer prognosis. Less well-known and less common is tumor extension into the anterior segment of the eye. The importance of this type of invasion is that it also increases the risk of metastases. The authors evaluated 42 children with RB and had all of the enucleated eyes for comparison. MR showed moderate or strong contrast enhancement of the anterior segment in nearly 70% of patients. What is the reason for this? Enhancement of the anterior eye segment is due to either simple angiogenesis or tumor invasion. However, tumor extension anteriorly seems to be present mostly with large tumors, many already extending into the optic nerve. Thus, enhancement of the anterior eye segment is not always due to tumor extension.

Value of Coronal Reformations in the CT Evaluation of Acute Head Trauma • S.C. Wei, S. Ulmer, M.H. Lev, S.R. Pomerantz, R.G. González, and J.W. Henson
This study looks at a simple issue: are coronal reformatted images obtained from routine brain CT scans useful in acute head trauma? With the ability to do this rapidly, is it something our residents and fellows (and we) should do in patients with acute head trauma? The authors included all acute brain trauma patients undergoing noncontrast head CTs studied in a 6-month period. The original images were done at 5-mm thickness and the coronal reformatted ones at 5-mm and 2.5-mm thickness. In 14% of patients with intracranial hemorrhage, the lesions were only seen in the coronal reformats. The coronal images excluded suspicious findings in a nearly equal number of patients. Overall, coronal images aided interpretation in 28% of instances and thus were considered helpful.

Familial versus Sporadic Cavernous Malformations: Differences in Developmental Venous Anomaly Association and Lesion Phenotype • T.A. Petersen, L.A. Morrison, R.M. Schrader, and B.L. Hart
We all know about the association between cerebral cavernomas and developmental venous anomalies. Most of us also know about the syndrome of multiple familial cerebral cavernomas. In this retrospective study, the authors looked at the MR imaging studies in a large series of patients with this syndrome in an attempt to determine if their cavernomas were also associated with DVAs. They evaluated more than 2200 cavernomas, most syndromic. They found nearly one-half of nonsyndromic cavernomas were accompanied by DVAs, but only 1:2176 familial ones had a DVA. Conclusion: familial cavernous malformations are almost never associated with DVAs so they may be a different disease than sporadic cavernomas.

The Safety of Dedicated-Team Catheter-Based Diagnostic Cerebral Angiography in the Era of Advanced Noninvasive Imaging • R. Thiex, A.M. Norbash, and K.U. Frerichs
More information on the common question: how safe is catheter angiography? This question is more relevant now than ever because of the high quality of noninvasive vascular studies. In this article, the safety of angiography done by dedicated individuals in a high-volume teaching hospital was assessed. The authors looked at their results in more than 1700 patients studied in a 9-year period. Specifically, they looked for those instances of patients who had suffered a transient ischemic attack or stroke presumably due to the angiogram (only 40 underwent diffusion-weighted imaging). There were no clinical strokes, 2 instances of abnormal punctate lesions on DWI, and 1 TIA. In 9 patients, non-neurologic complications occurred. They concluded that in this specific setting, complications from cerebral catheter angiography approach zero.

Identification of Infarct Core and Penumbra in Acute Stroke Using CT Perfusion Source Images • X.-C. Wang, P.-Y. Gao, J. Xue, G.-R. Liu, and L. Ma
Although the core of an infarct is clearly seen on diffusion-weighted imaging and corresponds to the hypodensity seen on initial CT images, it is not clear if source images from CT perfusion can consistently identify it. In this study, the authors imaged 42 patients with CTP (CBV and CBF) and used the source images and perfusion studies to try to identify the core and penumbra, then compared their results with those based on the Alberta Stroke Program Early CT Scores. They found that early arterial phase source images correlated well with ASPECTS on CBF and venous phase source images with ASPECTS on CBV. What does this mean? The hypoattenuated area in the venous source images represents the core whereas the hypoattenuated region on early arterial source images corresponds to the penumbra. Thus, the abnormality is always smaller on the venous phase images because they already incorporate collateral circulation. If this proves to be correct in larger studies, one may only need CT to image the acute stroke patient and it makes me wonder about the future role of MR imaging in the evaluation of the acute stroke patient.

Diffusion-Weighted MR Imaging Derived Apparent Diffusion Coefficient Is Predictive of Clinical Outcome in Primary Central Nervous System Lymphoma • R.F. Barajas Jr, J.L. Rubenstein, J.S. Chang, J. Hwang, and S. Cha
All of us know that in many central nervous system tumors increasing cellularity and MIB index correlate with lower apparent diffusion coefficient values and portray a worse prognosis. In this article, the authors set out to assess if this is also true of primary CNS lymphoma. They measured ADC in enhancing tumor regions in 18 immunocompetent patients with high-grade B-cell lymphomas before chemotherapy. ADCs were then correlated with histologic measurements of cellularity and survival analyses were performed. As expected, ADC measurements were heterogeneous but a correlation between cellular density and ADCs was present. Patients with tumors containing ADCs less than the median value of 692 had a significantly shorter progression-free interval and a shorter overall survival.

Diffuse White Matter Damage Is Absent in Neuromyelitis Optica • F. Aboul-Enein, M. Krssák, R. Höftberger, D. Prayer, and W. Kristoferitsch
It is well known that in most multiple sclerosis patients white matter is diffusely affected even if we cannot see it on conventional MR images. Is the white matter also diffusely involved in neuromyelitis optica (Devic disease)? Because NMO generally affects only the optic nerves and spinal cord even when it is recurrent, the authors postulated that white matter should not be diffusely involved as it is in MS. Using MR spectroscopy (obtained at 3T) they examined the white matter of 8 NMO patients and compared their results with those obtained in 8 healthy controls. They found that the normal-appearing white matter in both NMO patients and controls had similar MRS patterns. Thus, diffuse white matter damage is absent in NMO.

Do Iodinated Contrast Agents Impair Fibrinolysis in Acute Stroke? A Systematic Review • K.A. Dani and K.W. Muir
Non-human studies have shown the presence of iodinated contrast media impairs fibrinolysis of thrombus by thrombolytic agents. Obviously, this would be of significant importance for our neurointerventional colleagues treating acute stroke patients. The authors undertook a meta-analysis of the literature to see if this is true. They queried the Medline and EMBASE databases and found 6 studies in which contrast was used and 12 in which it was not. Conclusion: recanalization rates were similar in those patients who received contrast when compared to those who did not. Apparently they believe this evidence is enough, as they state that a randomized trial would require a prohibitively large number of subjects.

Fellows’ Journal Club

Complications of Particle Embolization of Meningiomas: Frequency, Risk Factors, and Outcome • D.F.M. Carli, M. Sluzewski, G.N. Beute, and W.J. van Rooij
Embolization of meningiomas, particularly those in the skull base, is a fairly common preoperative request. During a 15-year period the authors embolized 201 meningiomas (198 patients), most as an adjunct to surgery or radiosurgery though embolization was the primary form of treatment in 28 instances. They basically assessed the occurrence of 2 complications: neurologic deficits and postembolization death. Complications occurred in 11 patients; 10 were hemorrhagic and required surgery and 1 was ischemic. Two deaths were secondary to the procedure. The only risk factor found was the use of use of small particles. The authors discourage the use of these small particles for preoperative meningioma embolization.

Immediate Anatomic Results after the Endovascular Treatment of Unruptured Intracranial Aneurysms: Analysis of the ATENA Series • L. Pierot, L. Spelle, F. Vitry, and ATENA investigators
Here’s another large aneurysm coil study, predominantly from France, which nicely complements last month’s Fellows’ Journal Club choice and podcast ( S. Gallas, A.C. Januel, A. Pasco, J. Drouineau, J. Gabrillargues, A. Gaston, C. Cognard, and D. Herbreteau. Long-Term Follow-Up of 1036 Cerebral Aneurysms Treated by Bare Coils: A Multicentric Cohort Treated between 1998 and 2003. AJNR Am J Neuroradiol 2009;30:1986-92 originally published online on August 13 2009, 10.3174/ajnr.A1744). In the present study, immediate anatomic results in a large series (694 aneurysms in 622 patients) of unruptured aneurysms treated via endovascular approach were assessed. The results were stratified according to the Montreal scale and showed occlusion in 63%, neck remnants in nearly 23%, and aneurysm remnants in nearly 15%. Results were affected by size of the aneurysm and neck but not by location. The authors concluded that endovascular treatment provided satisfactory occlusion rates.

Postsurgical Intracranial Hypotension: Diagnostic and Prognostic Imaging Findings • D.R. Hadizadeh, A. Kovács, H. Tschampa, R. Kristof, J. Schramm, and H. Urbach
Postoperative intracranial hypotension has been implicated in poor clinical outcomes after uneventful neurosurgical procedures. In this study, the authors describe the imaging findings in patients with symptomatic intracranial hypotension induced by wound suction drainage. They review their experience with 3 patients and also review previously published cases. Sixteen patients were unconscious and showed abnormalities in the brain stem and/or basal ganglia after surgery. Eventually, 4 of them died. All showed findings compatible with CSF loss by CT and/or MR imaging. Conclusion: CT/MR imaging readily characterized postoperative intracranial hypotension and these findings underline the potential danger of wound suction drainage.

Sixty-Four-Section Multidetector CT Angiography of Carotid Arteries: A Systematic Analysis of Image Quality and Artifacts • J.J. Kim, W.P. Dillon, C.M. Glastonbury, J.M. Provenzale, and M. Wintermark
Now that most of us use 64-section CT scanners for our vascular work, it is important to know what image quality to expect and which artifacts may occur. That is exactly what the authors of this article set out to do. They retrospectively reviewed 100 CT angiography studies done for suspected stroke. First they assessed the degree of vascular density in different arterial segments, and then they assessed contrast differences between arteries and veins. They also recorded the presence of 6 artifacts: streaks from metal or slow-flowing contrast in adjacent veins, shoulder streaks, venous reflux, motion, and misregistration. Arterial opacification was good (97%) as was contrast between arteries and veins (86%). The most important artifacts were related to flow and mimicked dissections in 14% of patients. The authors concluded that in more than 95% of cases, 64-section CTA yields high-quality studies. See also in this issue the following article: J.Y. Chen, A.C. Mamourian, S.R. Messe, and R.L. Wolf. Pseudopathologic Brain Parenchymal Enhancement due to Venous Reflux from Left-Sided Injection and Brachiocephalic Vein Narrowing. AJNR Am J Neuroradiol 2010;31:86-87 first published on August 6, 2009 as doi: 10.3174/ajnr.A1688.

Association of White Matter Hyperintensity Measurements on Brain MR Imaging with Cognitive Status, Medial Temporal Atrophy, and Cardiovascular Risk Factors • J. Appel, E. Potter, N. Bhatia, Q. Shen, W. Zhao, M.T. Greig, A. Raj, W.W. Barker, H. Potter, E. Schofield, Y. Wu, D.A. Loewenstein, and R. Duara
Features of cardiovascular-related brain changes may overlap somewhat with those of Alzheimer patients. In this prospective study, the authors evaluated the presence and severity of white matter hyperintensities and mesial temporal atrophy in 192 patients with no cognitive impairment, mild cognitive impairment, and probable Alzheimer disease. Cardiovascular risk factors were also calculated for all. Both abnormalities were more common in patients with probable Alzheimer disease than in those with no cognitive impairment. White matter changes were related to temporal atrophy but not to cardiovascular risk factors. The results suggest that white matter changes in Alzheimer patients are probably related to neurodegeneration and not underlying cardiovascular conditions.

Brain Structural Variability due to Aging and Gender in Cognitively Healthy Elders: Results from the São Paulo Ageing and Health Study • P.K. Curiati, J.H. Tamashiro, P. Squarzoni, F.L.S. Duran, L.C. Santos, M. Wajngarten, C.C. Leite, H. Vallada, P.R. Menezes, M. Scazufca, G.F. Busatto, and T.C.T.F. Alves
Here is more information on the aging brain. These Brazilian investigators culled morphometric and volumetric gray matter data from 132 patients enrolled in a long-term study. They compared these data to age with the purpose of identifying regional age-related volume alterations in elderly individuals. It seems that we men (these findings were not seen in any of the women) have accelerated gray matter losses in temporal and prefrontal neocortex and in mesial temporal cortex, too. The authors concluded that atrophy of these regions is a part of the normal aging process.

The Effect of Exercise on the Cerebral Vasculature of Healthy Aged Subjects as Visualized by MR Angiography • E. Bullitt, F.N. Rahman, J.K. Smith, E. Kim, D. Zeng, L.M. Katz, and B.L. Marks
Here is additional information that exercising is good for you. There is some evidence that aerobics may reduce brain atrophy and white matter changes seen with advancing age. These investigators assessed differences in brain vasculature as seen on MR angiography in patients with high and low levels of physical activity. The arteries were segmented, their numbers counted, and their radii and tortuosity evaluated. Not surprisingly, the authors found that aerobically active subjects have significantly fewer tortuous vessels and a larger number of smaller arteries. Thus, it is possible that exercise contributes to healthy brain aging.

Fellows’ Journal Club

Long-Term Follow-Up of 1036 Cerebral Aneurysms Treated by Bare Coils: A Multicentric Cohort Treated between 1998 and 2003 • S. Gallas, A.C. Januel, A. Pasco, J. Drouineau, J. Gabrillargues, A. Gaston, C. Cognard, and D. Herbreteau
Finally, long-term results of endovascular treatment of aneurysms are becoming available. In this study from France, a large cohort of patients treated between 5-10 years ago with bare platinum coils were followed annually with MR imaging and catheter digital subtraction angiography. After initial treatment, complete occlusion was demonstrated in slightly more than 70% of patients, subtotal occlusion in 24%, incomplete occlusion in 2%, and failure of occlusion in 3%, leading to a second procedure in 72 (7%) of the original 1063 aneurysms. Retreatment was due to an initial incomplete occlusion or to later recanalization. Fewer than 5 patients rebled during the 10-year follow-up period. As I imagined, retreatment is not common and even in the face of incomplete occlusions the rate of rebleeding is very small.

Subsequent Fracture after Percutaneous Vertebroplasty Can Be Predicted on Preoperative Multidetector Row CT • A. Hiwatashi, T. Yoshiura, K. Yamashita, H. Kamano, T. Dashjamts, and H. Honda
You do a vertebroplasty and in a few months the patient develops another painful fracture in an adjacent vertebra. It would be nice to know which vertebrae are prone to this. Here, the authors prospectively evaluated 26 patients with 58 fractured vertebrae using CT multiplanar reformations 1 day pre-procedure. In those with recurrent pain at least 3 months after the initial treatment, spine MR imaging was done. New fractures occurred in 28 vertebrae, 14 adjacent to the treated one and 14 remote to it. Risk factors included use of steroid medications and low CT attenuation. Further collapse of the treated vertebrae was documented in 10 patients. (You may also want to read the Editorial and accompanying Commentary related to vertebroplasties that appear in this issue.)

Is All “Communicating” Hydrocephalus Really Communicating? Prospective Study on the Value of 3D-Constructive Interference in Steady State Sequence at 3T • A. Dinçer, S. Kohan, and M.M. Özek
After first reading this article, we started doing the CISS sequence in these patients and I am happy to report that it works well. That is, not uncommonly one discovers a culprit for the so-called “communicating hydrocephalus.” The authors of this study used 3D-CISS and phase-contrast flow studies to image 134 patients with large ventricles and no apparent cause on conventional sequences. The CISS studies detected obstructing membranes in 20% of patients who were later treated endoscopically instead of via shunt. The authors’ conclusion is that CISS images can document obstructing membranes, particularly in the fourth ventricle, and basal cisterns and this affects management and prognosis.

Angiographic and Clinical Outcomes in 200 Consecutive Patients with Cerebral Aneurysm Treated with Hydrogel-Coated Coils • T. Gunnarsson, F.C. Tong, P. Klurfan, C.M. Cawley, and J.E. Dion
Because this issue features interventional content, here is another related article. Hydrophilic coated coils absorb fluid and expand inside an aneurysm, theoretically leading to better packing and lower recanalization rates. The authors retrospectively studied their immediate and intermediate term results using HydroCoils in the treatment of 200 consecutive aneurysms. They also looked into complications. Initially, they were able to obliterate about one-half of small and large aneurysms. At 16 months, recanalization was present in 18% of small and 29% of large aneurysms. Periprocedural adverse effects were seen in 6% of patients. The authors concluded that first-generation hydrophilic coils performed at least as well as bare platinum ones.

Treatment of Stenoses of Vertebral Artery Origin Using Short Drug-Eluting Coronary Stents: Improved Follow-Up Results • Z. Vajda, E. Miloslavski, T. Güthe, S. Fischer, G. Albes, A. Heuschmid, and H. Henkes
With this article, we continue our emphasis on interventional treatment. Stenoses at the vertebral artery origin seem to be different than carotid ones and are known to respond immediately and very favorably to stent insertion. Unfortunately, the long-term results are not that great. These investigators used drug-eluting coronary stents for this purpose with the idea that they may improve long-term results. Thus, they treated 48 patients who were thereafter anticoagulated. They were able to immediately reduce the degree of the stenoses about 4-fold and at a 7-month follow-up only 12% of patients were judged to have significant recurrent narrowings. Conclusion: these special stents are safe and do a good job in maintaining a midterm patency rate.

Anisotropic Diffusion Properties in Infants with Hydrocephalus: A Diffusion Tensor Imaging Study • W. Yuan, F.T. Mangano, E.L. Air, S.K. Holland, B.V. Jones, M. Altaye, and K. Bierbrauer
Here the authors seek to determine the effect of ventricular dilation upon adjacent white matter using diffusion tensor imaging. For their study, they retrospectively assessed DTI studies in 17 children with hydrocephalus and compared them with 17 similar controls. They obtained measurements in 5 white matter regions plus the callosum and internal capsules. Abnormal metrics were obtained in hydrocephalic subjects in most white matter regions interrogated, in the callosum, and to a lesser extent in the internal capsules. They concluded that hydrocephalus leads to abnormalities in most of the white matter examined.

Fellows’ Journal Club

Diffusion Tensor Imaging of the Subcortical Auditory Tract in Subjects with Congenital Cochlear Nerve Deficiency • C.-M. Wu, S.-H. Ng, J.-J. Wang, and T.-C. Liu
If your cochlear nerve is absent, do you still have the normal intracerebral connections for the auditory pathway? This is the question asked by this group of investigators. They used DTI at 3T in 12 patients with unilateral absent cochlear nerve and in 12 controls. Then they measured fractional anisotropy and mean diffusivity at different points along the auditory pathways in both groups. Preserved axial diffusion bilaterally in patients implies that the tracts are present, but the fact that bilaterally they had low FA and high MD (when compared to controls) suggests that these tracts are not normal but have axonal loss and/or demyelination.

Is CT Still Useful in the Study Protocol of Retinoblastoma? • P. Galluzzi, T. Hadjistilianou, A. Cerase, S. De Francesco, P. Toti, and C. Venturi
Exposure to radiation from CT has received considerable attention lately and it is very important in children, especially if multiple studies are contemplated. CT has been used traditionally for the diagnosis of retinoblastoma because of the lesion’s intrinsic calcium. The authors retrospectively analyzed a gamut of different MR sequences and correlated their findings with those of CT, clinical examination, and histology (in some cases sonography, too) in 28 tumors. The best techniques to detect calcium were US and CT (about 95% each), but MR was close behind (nearly 90%). If you combine the clinical and MR data, no calcifications were missed and thus MR imaging works well for the diagnosis of retinoblastoma, saving patients radiation exposure.

Evaluation of the Occlusion Status of Coiled Intracranial Aneurysms with MR Angiography at 3T: Is Contrast Enhancement Necessary? • M.E.S. Sprengers, J.D. Schaafsma, W.J. van Rooij, R. van den Berg, G.J.E. Rinkel, E.M. Akkerman, S.P. Ferns, and C.B.L.M. Majoie
Wouldn’t it be great to avoid doing catheter angiograms in post-coiled aneurysms? MR angiography at 3T is exquisite and the authors sought to determine if adding gadolinium to this technique further improves the detection of residual lesion lumen. Six months after coiling, they examined 72 aneurysms using time-of-flight MRA before and after contrast administration. The correlation of both MRA techniques with angiography was good and both showed similar results. Interobserver agreement was excellent. Thus, noncontrast MRA suffices for this purpose. (For controversies regarding this issue, read the Opinion and Counterpoint articles found in this issue in the Research Perspectives section.)

Intelligence and Medial Temporal Lobe Function in Older Adults: A Functional MR Imaging-Based Investigation • D.M. Yousem, M.A. Yassa, C. Cristinzio, I. Kusevic, M. Mohamed, B.S. Caffo, and S.S. Bassett
In this interesting prospective study, the influence of intelligence and education on cortical activation of the temporal lobes was studied. The authors recruited 38 adults and subjected them to auditory paradigms thought to activate the medial temporal lobes. Results of fMRI were then correlated with IQs and educational levels (assuming there is a relationship between both). All subjects had normal IQs and time spent in education varied widely. The degree of activation did not correlate with IQs or levels of education, implying these need not be taken into consideration when designing fMRI studies.

Diffusion Tensor Imaging Shows Different Topographic Involvement of the Thalamus in Progressive Supranuclear Palsy and Corticobasal Degeneration • A. Erbetta, M.L. Mandelli, M. Savoiardo, M. Grisoli, A. Bizzi, P. Soliveri, L. Chiapparini, S. Prioni, M.G. Bruzzone, and F. Girotti
Progressive supranuclear palsy and corticobasal degeneration have different imaging, pathologic, and, at times confusing, clinical features. In this study, the investigators decided to use diffusion tensor imaging to assess possible microstructural abnormalities in the thalami and their cortical connections in these 2 diseases. After measuring fractional anisotropy in several thalamic, white matter, and cortical locations, they found that in PSP, anisotropy was elevated in the anterior thalami but decreased in white and superficial gray matter. In CBD, FA was asymmetrically elevated only in the motor thalami but was also high in many regions of white matter and cortex. They suggest DTI may be used to differentiate these 2 movement disorders.

Added Value and Diagnostic Performance of Intratumoral Susceptibility Signals in the Differential Diagnosis of Solitary Enhancing Brain Lesions: Preliminary Study • H.S. Kim, G.-H. Jahng, C.W. Ryu, and S.Y. Kim
The quest to find yet another MR imaging sequence that may differentiate solitary metastasis from primary brain tumors continues. In this article, the authors evaluated the added value of susceptibility abnormalities seen inside brain masses in 64 patients. They subjectively attempted to predict the nature of the masses based on the susceptibility effects as seen on SWI and then quantitatively evaluated their results. In 67% of cases they used the SWI findings to successfully distinguish tumoral from non-tumoral lesions. Malignant lesions, such as glioblastoma multiforme and metastases, had the highest percentages of signal abnormalities and could not be separated. SWI was able to separate GBM from lymphoma in 100% of instances.

Fellows’ Journal Club

Temporal Association of Annular Tears and Nuclear Degeneration: Lessons from the Pediatric Population • A. Sharma, M.S. Parsons, and T.K. Pilgram
The fact that annular tears precede degeneration of the nucleus pulposus in adults is well known, but the authors of this article state that this sequence of events is not clear in children. Based on the hypothesis that tears precede degeneration even at a young age, they studied all lumbar disks in 26 children who had spinal MR imaging. They looked at the association between annular tears and nuclear MR imaging changes. Although we radiologists have always been taught that children are not little adults, in this case they seem to be: degenerated disks generally had accompanying annular tears while degenerated disks with intact annuli were seen in only 3% of patients.

Prevalence of Hippocampal Malrotation in a Population without Seizures • R.P. Gamss, S.E. Slasky, J.A. Bello, T.S. Miller, and S. Shinnar
If you have a busy epilepsy unit in your hospital, you are probably doing coronal imaging looking for mesial temporal sclerosis and finding a significant number of malrorated hippocampi. Many believe that malrotation of the hippocampus is a developmental aberration that is not associated with symptoms. In this study, the authors looked for unilateral malrotations in nearly 500 MR imaging studies that included coronal images of the temporal lobes done in patients without seizures. Only 6 individuals had malrotated hippocampi and thus they concluded that malrotation must be a pathological finding when seen.

Anterior-Segment Retinoblastoma Mimicking Pseudoinflammatory Angle-Closure Glaucoma: Review of the Literature and the Important Role of Imaging • R.R. Saket and M.F. Mafee
Now and then I include a Case Report as a reading recommendation for the fellows and this is such an occasion. When one sees enhancement of the anterior segment of the eye in a child with a retinoblastoma, one should assume that the tumor has extended into the aqueous chamber. This is generally seen in fairly advanced tumors and usually precludes more conservative therapy. Fortunately, in some of these children this enhancement is nothing more than reactive neovascularity. When enhancement is seen only in the anterior eye segment—as in this case—the differential diagnosis changes, but, as demonstrated by the authors, retinoblastoma can also occur in this location.