2. U-King-Im JM, Fox AJ et al.    Characterization of Carotid Plaque Hemorrhage: A CT Angiography and MR Intraplaque Hemorrhage Study. Stroke 2010;41:1623-1629.  The authors did not find mean plaque density to be a useful factor for prediction of MR defined IPH. There was significant overlap between the mean plaque densities between the hemorrhagic and the nonhemorrhagic plaque groups. They did find a strong in vivo association between CTA plaque ulceration and IPH as defined by MR-IPH.

3. Raybaud C.  The corpus callosum, the other great forebrain commissures, and the septum pellucidum: anatomy, development, and malformation.  Neuroradiology (2010) 52:447–477.  This is a massive review.  I suggest a very large caffeinated drink prior to attempted reading.  Some things don’t change: the physiological role of the indusium griseum is still unknown.

4. Hassan AE, Zacharatos, H et al.  A Comparison of Computed Tomography Perfusion-Guided and Time-Guided Endovascular Treatments for Patients with Acute Ischemic Stroke. Stroke 2010; 41:1673-1678.  69 patients underwent CT-P-guided and 127 patients underwent time guided endovascular treatment.  CT-P guided endovascular treatment (compared with conventional time-guided endovascular treatment) was not associated with improved short-term outcomes.  Very interesting counterpoint to the utility of CTP, especially given the recent negative press concerning radiation dosage.

5. Ebinger M., et al. Clinical and Radiological Courses Do Not Differ Between Fluid-Attenuated Inversion Recovery-Positive and Negative Patients With Stroke After Thrombolysis.  Stroke 2010;41:1823-1825.  No significant difference was found in terms of lesion growth or neurological changes after thrombolysis between FLAIR-positive and FLAIR-negative patients. Thrombolysis should not be withheld solely based on FLAIR lesion visibility.

6. Soto-Pérez-de-Celis, E.  The Death of Leon Trotsky. Neurosurgery 67:417-423, 2010. In 1940, a Stalinist agent wounded Trotsky in the head with an ice axe in his house in Coyoacán, Mexico, where he was living in exile.  His assassin, Frank Jacson, after his release from prison, spent his time between Cuba and the Soviet Union, where he received the nation’s highest distinction, the Hero of the Soviet Union medal.  That Stalin, what  a guy.

7. Cloyd JM et al. En Bloc Resection for Primary and Metastatic Tumors of the Spine: A Systematic Review of the Literature. Neurosurgery 67:435-445, 2010. Median time to total recurrence for primary tumors was 113 months and for metastatic tumors was 24 months.  En bloc tumor excisions are highly complex and technically demanding procedure with average operating time of 12.1 hours, estimated blood loss of 3.7 L, and complication rate of 36.3%.  The comments are worth reading, and give a nice summary of current thinking regarding en bloc resection vs. lesion resection with chemo and radiation.

8. Scoccianti S., et al. Patterns of Care and Survival in a Retrospective Analysis of 1059 Patients with Glioblastoma Multiforme Treated Between 2002 and 2007.  Neurosurgery 67:446-458, 2010. Median survival was 9.5 months, and actuarial overall survival rates at 1, 2, and 5 years were 62.3%, 24.8%, and 3.9%, respectively.  Patient characteristics associated with a better prognosis included younger age at diagnosis, single lesion, absence of focal symptoms at diagnosis, and higher preoperative KPS score. One small glimmer of hope is the percentage of patients with long term survival (4-year 6.8%; 5-year 3.9%).

9. Pitt D., et al.  Imaging Cortical Lesions in Multiple Sclerosis with Ultra–High-Field Magnetic Resonance Imaging. Arch Neurol 2010; 67(7):812-818. This is a detailed assessment of the sensitivity of 3-D T2*GRE and 3-D inversion recovery WM attenuated turbo-field-echo (TFE) sequences at 7 T in formalin-fixed MS brains in three patients evaluating cortical demyelination. 46% (T2*GRE) and 42% (WHATTFE) of histologically confirmed lesions were seen on prospective scoring. These scores improved to 93% and 82%,respectively, on retrospective scoring. Lesion visibility was partially determined by size as all undetected lesions had a diameter of 1.1 mm or less.  Very impressive image quality.

10. Fisher CG, Vaccaro AR.  The Highest Level of Evidence in a High Impact Journal: Is This the Final Verdict? Spine 2010; 35 (15): E676-E677.  More fodder for the vertebroplasty debate.  They do make an interesting comparison to femur fractures: The natural history of femur fractures is healing by 6 to 12 months regardless of treatment. The goal of internal fixation is early mobilization and pain control.  The authors ask the question: Would anyone for go internal fixation of a femur fracture because of the equivocal long-term fracture healing?

11. Thompson PM, Martin MG, Wright MJ. Imaging genomics. Current Opinion in Neurology 2010, 23:368–373.  Nice reference list for an area of research to which I pay little (or no) attention.

12. Mirzayan MJ et al. Extended Long-Term (>5 Years) Outcome of  Cerebrospinal Fluid Shunting in Idiopathic Normal Pressure Hydrocephalus. Neurosurgery 67:295-301, 2010. Fifty-one patients (mean age of 70) were included after confirmation of the diagnosis by extensive clinical and diagnostic investigations. Surgery included ventriculoatrial or ventriculoperitoneal shunting with differential pressure valves. Shunt-related mortality was negligible and the main cause of death was vascular comorbidity. Nice table summarizing the literature regarding long-term follow-up studies after shunting in iNPH.

13. Langner S et al. Perfusion CT scanning and CT angiography in the evaluation of extracranial-intracranial bypass grafts. J Neurosurg July 9, 2010. Perfusion CT allows monitoring of hemodynamic changes after bypass surgery. The combination of both modalities enables noninvasive anatomical and functional analysis of superficial temporal artery–middle cerebral artery anastomoses using a single CT protocol.  Didn’t we know this already? We use both all the time in our by-pass population.

14. Barkovich AJ.  Current concepts of polymicrogyria.  Neuroradiology 52: 479-487, 2010.  Everything you need to know in one place….’nuff said.

15. Tubbs RS et al.  Retroclival Epidural Hematomas: A Clinical Series. Neurosurgery 67:404-407, 2010. As Dr. Heger noted in the comments section, 25% of their patients experience occipital cervical dissociation and required stabilization surgery underscores the need for a high index of suspicion for spinal instability in all cases of REDH. 5 of the 6 surviving patients had minimal to no neurologic deficit on long term follow-up indicates that the prognosis from this lesion may be good.

16. Rutherford MA, et al. Magnetic resonance imaging of white matter diseases of prematurity. Neuroradiology (2010) 52:505–521.  Excellent review article with loads of images.  Highly recommended.

Every year in the United States, more than three quarters of a million people have a stroke, and approximately every 3 minutes someone dies from a stroke. A significant portion of stroke victims are young, and left with a devastating handicap for the rest of their lives. The monetary and societal costs of stroke represent a major economic challenge to the healthcare system.  With stroke – as with heart attack – rapid treatment is essential to limit the extent of irreversible brain injury (“time-is-brain”), and rapid determination of the cause and degree of existing brain injury can be critical in deciding treatment.

CT perfusion imaging is a quick, widely available test that displays information about blood flow to the brain that can help diagnose, treat, and predict outcome in stroke patients.  When MRI is not readily available or contraindicated, CT perfusion imaging provides the best possible estimate of brain tissue likely to die without urgent, advanced therapies, including arterial “clot busting” drugs and blood clot retrieval devices.  CT perfusion imaging can also help classify reversible brain injury (“transient ischemic attacks”) that – like cardiac angina – may not require such immediate, aggressive treatment, as well as evaluate brain injury caused by arterial spasm due to bleeding from aneurysm rupture.

Published protocols for performing CT perfusion imaging at “as low a radiation dose as reasonably achievable” – a principle endorsed by the American College of Radiology and American Society of Neuroradiology – have circulated in the medical community for over a decade.  Strict protocol rules and oversight radiation protection personnel at most medical centers ensure that optimal image quality is maintained with a total radiation exposure often considerably lower than the current FDA recommended maximum dose.  Indeed, in an early, highly quoted study that compared different scanning protocols, it was shown that image quality is actually improved when CT perfusion is obtained at a lower average X-ray beam energy than is standard for routine CT imaging.

In all of medicine – and especially for stroke – the potential risks of any diagnostic test or therapeutic procedure (however rare) must be weighed against the very real benefits of preventing death or severe disability.  We believe, and the medical literature supports, that CT perfusion imaging, when appropriately performed, is justified and provides safe, valuable information that can substantially contribute to the management of acutely ill patients in an emergency setting.  Recent advances in scanner hardware and software, and the ongoing efforts of industry, offer the promise of further, significant reductions in CT radiation dose. The radiology community is committed to work hard towards this goal of reducing CT radiation dose, and continuing to offer the best imaging care to our patients.

References:

Janet C Miller, D. Phil., et al. CT Perfusion Imaging of the Brain. Radiology Rounds: A Newsletter for Referring Physicians from the Massachusetts General Hospital Department of Radiology. Volume 8, Issue 6, June 2010. http://www.mghradrounds.org/index.php?src=gendocs&ref=2010_june

Wintermark M, Lev MH. FDA investigates the safety of brain perfusion CT. AJNR Am J Neuroradiol. 2010 Jan;31(1):2-3.

Latchaw RE, Alberts MJ, Lev MH, Connors JJ, Harbaugh RE, Higashida RT, Hobson R, Kidwell CS, Koroshetz WJ, Mathews V, Villablanca P, Warach S, Walters B; American Heart Association Council on Cardiovascular Radiology and Intervention, Stroke Council, and the Interdisciplinary Council on Peripheral Vascular Disease. Recommendations for imaging of acute ischemic stroke: a scientific statement from the American Heart Association. Stroke. 2009 Nov;40(11):3646-78.

Wintermark M, Rowley HA, Lev MH. Acute stroke triage to intravenous thrombolysis and other therapies with advanced CT or MR imaging: pro CT. Radiology. 2009 Jun;251(3):619-26.

Wintermark M, Maeder P, Verdun FR, Thiran JP, Valley JF, Schnyder P, Meuli R. Using 80 kVp versus 120 kVp in perfusion CT measurement of regional cerebral blood flow. AJNR Am J Neuroradiol. 2000 Nov-Dec;21(10):1881-4.

Broad expert consensus on the minimum requirements for CT perfusion scan acquisition can be found in Table 2 (page E25) of the following paper, which can be freely downloaded from PubMed:

Wintermark M, Albers GW, Alexandrov AV, Alger JR, Bammer R, Baron JC, Davis S, Demaerschalk BM, Derdeyn CP, Donnan GA, Eastwood JD, Fiebach JB, Fisher M, Furie KL, Goldmakher GV, Hacke W, Kidwell CS, Kloska SP, Köhrmann M, Koroshetz W, Lee TY, Lees KR, Lev MH, Liebeskind DS, Ostergaard L, Powers WJ, Provenzale J, Schellinger P, Silbergleit R, Sorensen AG, Wardlaw J, Wu O, Warach S. Acute stroke imaging research roadmap. AJNR Am J Neuroradiol. 2008 May;29(5):e23-e30.

The loss of CSF volume explains the usual complaint of orthostatic headache, relieved by lying down, and the characteristic MRI findings: 1) thickening of the dura, enhancing after contrast medium administration, 2) subdural fluid collections, 3) sagging of the brain, 4) dilatation of the venous structures, which includes enlargement of the dural sinuses and veins, enlargement of the pituitary gland, and, in the spinal canal, engorgement of the epidural plexuses. All these features are explained by the Monro-Kellie doctrine: in a closed compartment, such as the intracranial cavity and spinal canal, which contains nervous tissue, blood, and CSF, the loss of one component is compensated by the equivalent increase of the other ones. Therefore, if a dural leakage causes a loss of CSF, an increase in nervous tissue or blood must compensate for that loss to re-establish the equilibrium. Obviously, the easiest compensation comes from an increase in blood, and specifically venous blood because the veins may dilate passively more than the arteries. In peculiar cases, the nervous tissue may participate in the compensation through swelling of the brain (Savoiardo et al. Brain 2007).

Most of the authors who have published papers on SIH, have shifted their emphasis from the loss of pressure in the closed system (intracranial hypotension) to the actual loss of volume of CSF. We agree that the loss of volume of CSF rather than its decreased pressure should be emphasized and pointed out in the denomination of this condition because it is more correct in terms of pathophysiology. However, the term “CSF hypovolemia”, that has been used by most authors, is wrong. We would like to point out again why this is so.

The suffix “emia” in “hypovolemia”, indicates blood, as in glycemia, uremia, and so on. Therefore, “CSF hypovolemia” means “decreased (hypo) volume (vol) of the blood (emia) of the CSF” which is a total nonsense. There is no “blood of the CSF”; moreover, we have seen that venous blood increases (“hypervolemia”) to compensate for the loss of CSF.

According to dictionaries, “hypovolia” exists and should be the correct term. However, since “hypovolia” has never been used and is unknown to most of us, we propose using “CSF loss of volume” or “decreased volume of CSF” rather than “CSF hypovolia”. In our opinion, “CSF hypovolemia” remains a misnomer and should be banned. This is probably a lost cause, but we think it’s worth using the precise terms.

We thank Dr. Neeraj Kumar and Dr. Mauricio Castillo for discussing this matter.

Mario Savoiardo and Marina Grisoli
Department of Neuroradiology
Foundation IRCCS Istituto Neurologico Carlo Besta
Milan, Italy

E-mail:
msavoiardo@istituto-besta.it
mgrisoli@istituto-besta.it

Savoiardo M, Minati L, Farina L, et al. Spontaneous intracranial hypotension with deep brain swelling. Brain 2007;130:1884-93.

Kumar N. Neuroimaging in superficial siderosis: an in-depth look. AJNR Am J Neuroradiol 2010;31:5-14.

Savoiardo M, Grisoli M. Further in-depth look at superficial siderosis (and intracranial hypotension). AJNR Am J Neuroradiol Published June 25, 2010 as DOI 103174/ajnr.A2172

Kumar N. Reply. AJNR Am J Neuroradiol Published June 25, 2010 as DOI 103174/ajnr.A2187

2. Kim KH et al.  Adjacent Segment Disease After Interbody Fusion and Pedicle Screw Fixations for Isolated L4–L5 Spondylolisthesis. Spine 2010;35:625–634. A low postoperative segmental lordotic angle, especially less than 20°, at index level was related with development of clinical ASD in both isthmic and degenerative spondylolisthesis patients.

3. Ribas GC .The cerebral sulci and gyri. Neurosurg Focus 28 (2):E2, 2010.  Very detailed review of the literature regarding the historical, evolutionary, embryological, and anatomical aspects of the cerebral sulci and gyri to establish detailed descriptions of these structures, as well as their groupings in the brain lobes, for microneurosurgical purposes.

4. Diaz FL et al.  Cervical External Immobilization Devices: Evaluation of Magnetic Resonance Imaging Issues at 3.0 Tesla. Spine 2010;35:411–415. Generation 80 and V1 Halo devices exhibited substantial temperature rises with “sparking” evident for the Generation 80 during the MRI procedure. Artifacts were problematic for these devices. The 2 Resolve Ring-based cervical external immobilization devices showed little or no heating and the artifacts were acceptable.

5. Harrop JS et al.  Cervical Myelopathy: A Clinical and Radiographic Evaluation and Correlation to Cervical Spondylotic Myelopathy. Spine 2010;35:620–624.  Nice review of clinical signs.  No patients without cord compression showed myelopathy.  The likelihood of myelopathy increases with the presence of T2 cord signal hyperintensity.

6. Monti MM et al. Willful Modulation of Brain Activity in Disorders of Consciousness. N Engl J Med 2010;362:579-89. Of the 54 patients enrolled in the study, 5 were able to willfully modulate their brain activity demonstrated by fMRI.

7. Ropper AH. Cogito Ergo Sum by MRI. N Engl J Med 2010; Feb 18, 362;7. Editorial accompanying the N Engl J Med article above. (I think, therefore I am).The author reminds us of three important concepts: First, in this study, brain activation was detected in very few patients. Second, activation was found only in some patients with traumatic brain injury, not in patients with global ischemia and anoxia. Third, cortical activation does not provide evidence of an internal “stream of thought”, memory, self-awareness, reflection, synthesis of experience, symbolic representations, anxiety, despair, or awareness of one’s predicament.

8. Kase CS, Nguen TN.  The clinical conundrum of convexal subarachnoid hemorrhage. Neurology 2010;74:874–875.  Editorial. “Convexal” SAH is frequently encountered in clinical practice, and presents at times with acute headache suggestive of SAH, but often it is an unexpected finding on imaging in patients evaluated for a variety of symptoms, including change in mental status, transient focal neurologic deficits, or partial seizures.

9. Kumar S, Goddeau RP et al. Atraumatic convexal subarachnoid hemorrhage:  Clinical presentation, imaging patterns, and etiologies.  Neurology 2010;74:893–899. Reversible vasoconstriction syndrome appears to be a common cause in patients 60 years or younger whereas amyloid angiopathy is frequent in patients over 60.

10. Lovblad K, Baird AE.  Computed tomography in acute ischemic stroke. Neuroradiology (2010) 52:175–187.  Comprehensive review of use of CT imaging and perfusion.

11. Kleiser R, Staempfli P et al.  Impact of fMRI-guided advanced DTI fiber tracking techniques on their clinical applications in patients with brain tumors. Neuroradiology (2010) 52:37–46.  DTI scan can be acquired in a few more scan minutes in the same scan session in which all the other necessary images for the surgery are acquired (anatomical and fMRI data). The data processing is performed offline with dedicated software packages without involvement of the patient.

12. Bello L et al. Intraoperative use of diffusion tensor imaging fiber tractography and subcortical mapping for resection of gliomas: technical considerations. Neurosurg Focus 28 (2):E6, 2010.  Shows the potential usefulness of the routine combined use of DT imaging–FT and subcortical mapping, particularly in patients with low-grade gliomas. These tumors display an infiltrative modality of growth, along short and long connecting fibers, and visualizing the trajectory of the tracts is important for planning and performing surgery.

13. Verhoeven JS et al.  Neuroimaging of autism. Neuroradiology (2010) 52:3–14.  This is an area I have not paid much attention too, so it is convenient to have an all encompassing review available.

14. Chhabra V, Sung E et al.  Safety of magnetic resonance imaging of deep brain stimulator systems: a serial imaging and clinical retrospective study.  J Neurosurg 112:497–502, 2010.  This retrospective MR imaging–based study supports the safety of MR imaging in patients with implanted DBS systems.  Because the indications for DBS continue to expand, it is likely that postoperative MR imaging will remain an important clinical tool.

15. Richards PJ, George J et al. Spine Computed Tomography Doses and Cancer Induction. Spine Volume 35, Number 4, pp 430–433.  Risk ratio for inducing a cancer when CT scanning the whole lumbar spine was about 1 in 3200, which was much less than the risk of CTing the whole dorsal spine (about 1 in 1800) due to the longer coverage required and the anatomic implications of scanning in the region of the cervical dorsal junction.

16. Karppinen J, Solovieva S et al. Modic changes and interleukin 1 gene locus polymorphisms in occupational cohort of middle-aged men. Eur Spine J (2009) 18:1963–1970.  The pathomechanism of LBP due to Modic changes (MC) remains poorly understood. It has been hypothesized that MC is a result of a biomechanically induced inflammation around the intervertebral disc.  This inflammatory etiology is also supported by the finding of an increased number of tumor necrosis factor immunoreactive nerve cells and fibers in endplates with MC, especially in type I changes [30].   This paper shows an association between IL1A gene variation and type II MC replicates a previous finding from a different Finnish geographic area,  confirming the importance of the ILA gene in the pathophysiology of MC.

17. Kim D, Wadley R. Variability in Techniques and Patient Safety Protocols in Discography. Journal of Spinal Disorders & Techniques, 27 January 2010. To improve diagnostic validity and patient safety, the International Spine Intervention Society (ISIS) has published practice guidelines for performing discography (Bogduk N, ed. Practice Guidelines for Spinal Diagnostic and Treatment Procedures. San Francisco: International Spine Intervention Society; 2004:20–46).  The overall compliance with ISIS guidelines is fair to poor with the specialty rank order of compliance greatest to least as follows: Anesthesiology, PMR, and Radiology.

18. Kim HS, Chong HS et al. Vascular Injury in Thoracolumbar Spinal Surgeries and Role of Angiography in Early Diagnosis and Management. Journal of Spinal Disorders & Techniques, 27 January 2010. Of the total 8 arterial injury cases, only 1 of them occurred in the thoracic region and the rest all were seen in the lumbar spine.  Pseudoaneurysm formation in thoracic aorta was seen in 1 case of multiple vertebral fractures, segmental artery was found to be injured in 3 cases of osteotomy for deformities, 2 cases of aortic injury and 1 case of inferior mesenteric artery injury was seen in posterior lumbar interbody fusion. Common iliac artery and vein both were seen to be injured simultaneously in 1 case of lumbar discectomy.

Clinically he was  diagnosed as having sustained a diffuse axonal injury and was treated conservatively.

A brain MRI was performed  one month following injury and a repeat one 1 year later.

Susceptibility WI at the one month interval  showed multiple microhemorrhages in both frontal lobes.

The one year follow-up MRI showed diffuse, symmetric, confluent hyperintensities in the  periventricular WM and these findings were not present on the initial MRI.

The question is whether the WM changes seen at the one-year follow up study are  related to the diffuse  axonal injury. The  microbleeds seen on SWI did not coincide exactly with  the WM changes.

2.  Is 80 the optimal kVp for the perfusion study?

Thanks

At this point, what is your diagnosis? Meningioma…… right?

Our pre-operative diagnosis was also meningioma. Only concern was that the diffusion restriction was little too much for a meningioma, even for a densely cellular anaplastic meningioma.

There were two surprises for us both from surgeons as well as from pathologists. When the surgeons opened the dura, the mass was intra-axial! When the pathologists saw the tumor under microscope, they found diffuse large B-cell lymphoma with very high proliferative index (90-95%) and officially they called it “Large B-cell lymphoma, diffuse, with high proliferative rate and intermediate features between Burkitt lymphoma and large cell lymphoma (WHO classification 2008)”.

This is a very interesting case because the tumor grew without following the ‘basic rules of neuroradiology’. Though the tumor arose from intra-axial compartment the way it enlarged and its internal morphology gave it a look of an extra-axial mass. This is not an uncommon dilemma of day to day neuroradiology practice. The best way to differentiate between pathologies at a given anatomic location is to execute a mental workout (I call it ‘Curé’s algorithm’) which is consisting of a) correct identification of the compartment from where the lesion arises, b) recall of normal structures of that compartment, c) recall of possible pathologies that can arise from the normal structures of that compartment, d) careful evaluation of the imaging appearances of the lesions in different imaging sequences/modalities and finally e) to perform an intensive mental database search for ‘curve fitting’ of the imaging appearances with the possible pathologies considered before. As the first step of the ‘Curé’s algorithm’ went wrong in this case, we ended up a wrong diagnosis even though there were subtle clues to the right diagnosis.

Though the patient presented with relatively short duration of frontal lobe symptoms and the tumor had prominent diffusion restriction we did not consider primary CNS lymphoma (PCNSL) as our provisional diagnosis because a) we thought the tumor was extra-axial, b) the incidence of primary leptomeningeal lymphoma (LL) is exceedingly rare and typical LL does not look like this, c) the tumor had high rCBV, a perfusion characteristic perfusion characteristic typically not seen in lymphoma and finally d) all imaging appearances other than diffusion restriction was ‘best-fit’ for meningioma.

PCNSL is an extranodal manifestation of non-Hodgkin’s lymphoma limited in central neuraxis including orbit, leptomeninges, spinal cord and cranial/spinal nerves without any other systemic manifestation. PCNSL constitutes 6-15.4% of all brain tumor, more common in men and usually occurs in patients >60 years of age. PCNSL is more commonly supratentorial (87%) and solitary (66%) in immunocompetent patient. Primary leptomeningeal lymphoma is a rare subtype of PCNSL limited to the meninges. Primary ocular lymphoma is another rare subset of PCNSL that involves vitreous, sub-retinal space or anterior chamber without systemic or CNS involvement. Up to 90% of these patients subsequently develop CNS lymphoma. Some authors also consider neurolymphomatosis as a variant of PCNSL. Neurolymphomatosis is very difficult to diagnose on MRI, particularly if the patient has no known lymphoma, either systemic or PCNSL.

The imaging appearance of the tumor depends upon the immune status of the patient. In immune competent patients, PCNSL is solid, T1 hypointense and iso- to slightly hyperintense on T2 weighted sequence. It can involve any area of brain but frontal lobe and basal ganglia are most commonly involved. It enhances brightly and homogenously with contrast. On diffusion weighted imaging, there is prominent diffusion restriction due to intense ‘packing’ of the tumor. Lymphoma is usually cold on perfusion imaging. PCNSLs in immunocompromised patients typically appear as peripherally located ring-enhancing lesions with central necrosis. They are often multiple. There may be diffusion restriction only at the periphery.

Iwamoto FM, DeAngelis LM. An update on primary central nervous system lymphoma. Hematol Oncol Clin North Am. 2006;20:1267-85

Shenkier TN. Unusual variants of primary central nervous system lymphoma. Hematol Oncol Clin North Am. 2005;19:651-64

Very nice review article with histopathology, imaging and helpful graphics

2.  Neuro-Behçet’s disease: epidemiology, clinical characteristics, and management.  Lancet Neurol 2009; 8: 192–204.

Behcet’s disease is a multisystem relapsing inflammatory disorder of unknown cause.  This review covers CNS parenchymal and nonparenchymal manifestations, as well as peripheral and uncommon variants.

3.  The protective status of subtotal obliteration of arteriovenous malformations after radiosurgery: significance and risk of hemorrhage.  Neurosurgery 65:709–718, 2009

Important paper evaluating the risk of AVM’s which show only early draining vein but no nidus following radiosurgery.  These “subtotally” obliterated AVM’s showed 0% rebleed rate.

4.  Microsurgical and endoscopic anatomy of the supratentorial arachnoidal membranes and cisterns.  Neurosurgery 65:644–665, 2009

More than I want to know about this topic, but nice to have as a reference.

5.  Hemispherotomy: efficacy and analysis of seizure recurrence.  J Neurosurg Pediatrics 4:000–000, 2009

Review of 49 patients who underwent functional hemispherotomy, with resultant freedom from seizures in 78%.

6.  Long term outcomes following surgical resection of myxopapillary ependymomas.  Neurosurg Rev (2009) 32:321–334

Retrospective review of 52 cases of spinal myxopapillary ependymomas.  Pediatric patients had much more aggressive tumors with recurrence and dissemination in 64%, vs. 32% in adults.  The role of radiotherapy and chemo is discussed.

7.  Neurosurgical implications of achondroplasia.  J Neurosurg Pediatrics 4:000–000, 2009

Review of treatment of pediatric patients with achondroplasia from Hospital for Sick Children, with focus on hydrocephalus and CV junction abnormalities.

8.  Occipital condyle fractures: clinical decision rule and surgical management.  J Neurosurg Spine 11:388–395, 2009

This is the kind of classification I like: presence or absence of craniocervical malalignment is the one important imaging parameter.  Malalignment was defined as C0-C1 interval on CT of >2mm.

9.  Comparison of clinical, familial, and MRI features of CADASIL and NOTCH3-negative patients.  Neurology  2010;74:57–63

Genetic analysis of 81 probands because CADASIL was suspected show no phenotypical differences between those with and without the mutation.

10.  Noninvasive testing, early surgery, and seizure freedom in tuberous sclerosis complex.  Neurology 2010;74:392–398

Evaluation of magnetic source imaing and PET/MRI coregistration techniques in 18 patients who underwent surgery.  Largest hypometabolic focus relative to the MR size seemed an important variable.

On surgery, the mass was encapsulated but the capsule was tightly adherent to the cerebellum. On histopathology, the tumor turned out to be a malignant fibrous histiocytoma (MFH) with 40% MIB-1 index.

MFH, the most common soft tissue sarcoma in adults, arises from fibroblasts, myofibroblasts or undifferentiated mesenchymal cells. Most patients are between 50 and 70 years old. Men are affected 2-3 times more commonly than women. Most MFHs arise de novo however, they can occur secondary to prior radiation, trauma, Paget’s disease, chronic osteomyelitis or benign bone tumors. MFH most commonly occurs in lower extremity. Head and neck area is involved up to 10% of cases.  In head neck, nasal cavity and paranasal sinuses are most commonly involved. It has variable appearances on CT and MRI. On CT, this is usually large lobulated sift tissue mass which is isodense to muscles with destruction/remodeling of adjacent bone. There may calcification in up to 5-20% of patients. On MRI, they are isointense to muscle on T1 weighted sequence and heterogeneously hyperintense on T2 weighted sequence. This tumor can have both solid and cystic component. Solid portion enhances intensely. Spontaneous hemorrhage is frequently seen and can obscure the primary tumor. The diagnosis is important because it is a malignant tumor and post-resection radiation therapy is required for better tumor control. MFH also has poor prognosis.

Suggested readings:

Nakayama K, Nemoto Y, Inoue Y, Mochizuki T, Soares SB, Ohata K, Katsuyama J, Onoyama Y and Wakasa K. Malignant fibrous histiocytoma of the temporal bone with endocranial extension.AJNR Am. J. Neuroradiol. 1997; 18: 331 – 4.

Park SW., Kim HJ., Lee JH, and Ko. YH. Malignant Fibrous Histiocytoma of the Head and Neck: CT and MR Imaging Findings. AJNR Am. J. Neuroradiol. 2009; 30: 71 – 6.