Elshafeey N, Hassan I, Zinn PO, Colen RR. From K-space to Nucleotide. Top Magn Reson Imaging. 2017;26(1):1. doi:10.1097/RMR.0000000000000114.
Radiogenomics is a relatively new field within radiology that links different imaging features with diverse genomic events. Genomics advances provided by the Cancer Genome Atlas and the Human Genome Project have enabled researchers to harness and integrate this information with noninvasive imaging phenotypes to create a better 3-dimensional understanding of tumor behavior and biology. This review summarizes the radiogenomic literature regarding brain tumors, both glioblastoma and lower grades.
As you know, the typical gross appearance of glioblastoma on MR is characterized as an irregular, ring-enhancing tumor with a central necrotic core and surrounding area of FLAIR hyperintensity. Each of these 3 imaging components (aka. phenotypes) of the tumor reflect a distinct tumor biology such as neovascularization and active tumor [contrast-enhancing component], edema/invasion (peritumoral T2/FLAIR hyperintensity), or cell death (necrosis). As an example of the potential power of volumetric features of glioblastoma on prognosis, in a cohort of 78 patients glioblastoma tumor volumes were quantified and combined with patient age and Karnofsky performance score (KPS) to create an easy-to-use 3-step scoring system VAK (Volume-Age, KPS) that can predict patient outcome.
Additionally, specific genomic and epigenetic events have shown a predilection for specific locations within the brain. As background, MGMT, a gene that encodes for a DNA repair enzyme, is associated with a better survival in those patients with MGMT promoter methylation receiving alkylating agents such as temozolomide. In treatment-naive glioblastoma patients, it has been found that patients with unmethylated O-6- methylguanine-DNA methyltransferase (MGMT) promoter predominated in the right temporal lobe. Glioblastoma with MGMT promoter methylation, EGFR amplification, and EGFRvIII mutations tended to occur in in the left temporal lobe. Most IDH1-mutated and intact PTEN tumors were in the frontal lobe.
Wilson JR, Tetreault LA, Kim J, et al. State of the Art in Degenerative Cervical Myelopathy: An Update on Current Clinical Evidence. Neurosurgery. 2017;80(3S):S33-S45. doi:10.1093/neuros/nyw083.
Degenerative cervical myelopathy (DCM) is used to describe myelopathy resulting from degenerative pathology in the cervical spine including spondylosis, degenerative disc disease, ossification of the posterior longitudinal ligament (OPLL), and ossification of the ligamentum flavum. The authors provide awide-rangingoverview ofthe state of the art in degenerative cervical myelopathy, with a focuson updating the spine surgeonon the current evidence surrounding pathophysiology,natural history, imaging, outcomemeasures, and outcome prediction tools. They also provide anoverview of the evidence for surgical vs. non–operativemanagement, and a summary of the literature regarding the most commonly used approaches to the cervical spine.
The pathophysiology of DCM includes both static and dynamic factors. Static factors result from congenital stenosis or acquiredstenosis secondary to spondylosis and disc degeneration.Dynamic factors relate to exacerbation of spinal cord compression seen with physiologicaland, in the setting of degenerative subluxation, pathologicalmotion of the cervical spine. In addition to physical compression, there is a reduction in blood supply leading to ischemia within the cord. Pathological features of DCM include gray and white matter degeneration, anterior horn cell loss, cystic cavitation, and Wallerian degeneration of the posterior columns adjacent to the site of compression.
There is also likely a secondary cascade of neuro–inflammation consistingof microglia activation and macrophage recruitment which occurs atthe site of mechanical compression within the spinal cord. Inthe non–compressed non–myelopathic spinal cord, the blood-spinal cord-barrier isisolated from the peripheral immune system; however, chroniccompression renders the cord susceptible to cell infiltrationthat may be involved in neural …
Zurawski J, Lassmann H, Bakshi R. Use of Magnetic Resonance Imaging to Visualize Leptomeningeal Inflammation in Patients With Multiple Sclerosis. JAMA Neurol. 2017;74(1):100. doi:10.1001/jamaneurol.2016.4237.
You are well aware that MS is a chronic demyelinating disease traditionally characterized by an initial relapsing-remitting clinical course and focal inflammatory lesions that have a predilection for the periventricular white matter. However, histopathologic and imaging studies have illustrated a more complex pathologic substrate involving cortical demyelination, gray matter atrophy, and meningeal inflammation. The authors evaluate the status and prospects regarding the emerging role of MR to visualize leptomeningeal enhancement (LME) in patients with MS and place these findings in the proper pathobiologic and clinical context.
Absinta et al (Absinta M, Vuolo L, Rao A, et al. Gadolinium-based MRI characterization of leptomeningeal inflammation in multiple sclerosis. Neurology. 2015;85(1):18-28.) found that LME was significantly more common than had been initially reported, and its presence was associated with patient age, disease severity, and clinical type of MS. The authors used high-resolution 3T 3-dimensional T2 FLAIR MRI with a voxel size of 1.0 × 1.0 × 1.0mm and postcontrast images obtained 10 minutes after gadolinium injection. They demonstrated LME in 74 of 299 patients with MS (24.7%) compared with only 1 of 37 (2.7%) age-matched controls with out MS. Perhaps of particular importance, LME was twice as frequent (33%) in patients with progressive forms of MS (present in 44 patients with secondary progressive MS) (SPMS) and 74 patients with primary progressive MS (PPMS) compared with those with relapsing-remitting (RR) disease (19%). Disease duration, and Expanded Disability Status Scale scores were associated with LME. Whole-brain and cortical atrophy were also associated with LME. There was no association between LME and WM lesion enhancement or WM lesion volume. Leptomeningeal enhancement topography abutted the pial surface on the cerebral convexity (19% …
AJNR has unveiled a brand new Web platform. In addition to the fresh modern design, easier navigation, and improved functionality, the site is now completely mobile-optimized. This eliminates the need for the Journal’s iOS app and at the same time addresses the Android market, which was underserved by the old platform. The new Web site is a major investment in the Journal’s on-line presence. It is built on HighWire Press’s Drupal-based architecture that allows increased capabilities and the flexibility to accommodate new features and changing technology.
Editor-in-Chief Jeffrey Ross shared his enthusiasm for the enhanced experience the new site brings to AJNR’s readers, saying, “We are excited to partner with HighWire and to bring to our readers a modern, responsive AJNR Web site using the JCore platform. Our readers will find an uncluttered interface, which presents both current and archival content in an easy to access format, with minimal click-through, and that is readily available on whatever device they choose to consume content.”
Dr. Ross selected an Altmetrics tool to analyze article level usage, reach, and social media impact as the first new function added to the site.
Please be sure to visit and bookmark the updated www.ajnr.org soon and share your feedback. Former users of AJNR’s iOS app should now access the site through their Safari browser.…
The AJNR is pleased to announce Vahe Zohrabian, M.D. as our fifth Editorial Fellow.
Dr. Zohrabian graduated from Columbia University with a degree in Biological Sciences and Sociology, and then attended New York Medical College. He completed his residency in Diagnostic Radiology at Thomas Jefferson University Hospital in Philadelphia, and then his fellowship at Yale-New Haven Hospital in Connecticut. He is currently an Assistant Professor in the Department of Radiology and Biomedical Imaging, Yale School of Medicine. Dr. Zohrabian has authored 7 peer-reviewed manuscripts and 9 book chapters. He has given numerous lectures at both regional and national meetings and was the recipient of the Outstanding Presentation Award in Spine Radiology at the ASNR meeting in 2011 for “Application of Diffusion Tensor Imaging as a Surrogate for Neurologic Deficit in Spinal Cord Injury.”
During his Editorial Fellowship, he will participate in all AJNR activities including, but not limited to, manuscript evaluation and selection, editorial-related research, and conferences. The AJNR family is very pleased to welcome Dr. Zohrabian.…
Daou B, Chalouhi N, Starke RM, et al. Clipping of previously coiled cerebral aneurysms: efficacy, safety, and predictors in a cohort of 111 patients. J Neurosurg. 2016;125(December):1-7. doi:10.3171/2015.10.JNS151544.
This retrospective cohort study evaluated the efficacy and safety of microsurgical clipping in the treatment of recurrent, previously coiled cerebral aneurysms and to identify risk factors that can affect the outcomes of this procedure. The mean patient age was 50.5 years, the mean aneurysm size was 7 mm, and 97.3% of aneurysms were in the anterior circulation. Complete aneurysm occlusion, as assessed by intraoperative angiography, was achieved in 97.3% of aneurysms (108 of 111 patients). Among patients, 1.8% had a recurrence after clipping. Retreatment was required in 4.5% of patients after clipping. Major complications were observed in 8% of patients and mortality in 2.7%. Ninety percent of patients had a good clinical outcome. Aneurysm size and location in the posterior circulation were significantly associated with higher complications. All 3 patients who had coil extraction experienced a postoperative stroke.
They conclude that surgical clipping is an appropriate treatment strategy for the management of recurrent cerebral aneurysms after endovascular coiling. Direct clipping of the aneurysm neck is feasible in most cases of recurrent, previously coiled cerebral aneurysms. Coil extraction should not regularly be attempted because it is associated with high morbidity. In other words, when direct clipping is not possible because of coil loops extending into the aneurysm neck, or with transmural calcification and scarring, other techniques such as wrapping should be considered.
Serrone JC, Tackla RD, Gozal YM, et al. Aneurysm growth and de novo aneurysms during aneurysm surveillance. J Neurosurg. 2016;125(6):1374-1382. doi:10.3171/2015.12.JNS151552.
Over an 11.5-year period, the authors recommended surveillance imaging to 192 patients with 234 unruptured intracranial aneurysms. The incidence of unruptured intracranial aneurysm growth and de novo aneurysm formation …
Domino JS, Baek J, Meurer WJ, et al. Emerging temporal trends in tissue plasminogen activator use. Neurology. 2016;87(21):2184-2191. doi:10.1212/WNL.0000000000003349.
Mexican Americans (MA) have an increased stroke burden when compared to their non-Hispanic white (NHW) counterparts, including increased stroke incidence and poorer neurologic, functional, and cognitive outcomes.
The authors explored the temporal trends in tissue plasminogen activator (tPA) administration for acute ischemic stroke (AIS) in a biethnic community without an academic medical center. Cases of AIS were identified from 7 hospitals in the Brain Attack Surveillance in Corpus Christi (BASIC) project, a population-based surveillance study from 2000-2012. There were 5,277 AIS cases identified from 4,589 individuals. tPA use was steady at 2% and began increasing in 2006, reaching 11% in subsequent years. Although ethnicity did not modify the temporal trend, Mexican Americans were less likely to receive tPA than non- Hispanic whites due to emerging ethnic differences in later years. The results suggest that increases in tPA use were greater in higher severity patients compared to lower severity patients, and a gap between MAs and NHWs in tPA administration may be emerging. The authors conclude that as physician experience with tPA and its use in community settings increases, follow-up studies should continue to explore temporal trends in tPA as well as identify possible strategies to improve tPA use in MAs.
2 Figures (graphs), 2 Tables
Goldstein LB. IV tPA for acute ischemic stroke. Neurology. 2016;87(21):2178-2179. doi:10.1212/WNL.0000000000003366.
In this editorial on the Domino et al. paper, Dr. Goldstein notes that there were considerable barriers that slowed IV tPA adoption after it was approved by the FDA in 1996. Eight years after FDA approval, IV tPA was being given to only 1%–2% of stroke patients. Transformation of the structure and organization of stroke care delivery were needed, and in part led to …
This award is named for the late AJNR Senior Editor who championed its establishment and recognizes the best original research paper accepted in 2016. The winning paper, submitted by authors from the Texas Children’s Hospital in Houston, was published electronically on October 13, 2016 and appeared in the February print issue. It was selected by a vote of the Journal’s Editor-in-Chief and Senior Editors.
Akoudad S, Wolters FJ, Viswanathan A, et al. Association of Cerebral Microbleeds With Cognitive Decline and Dementia. JAMA Neurol. 2016;73(8):934. doi:10.1001/jamaneurol.2016.1017.
The authors wanted to determine whether microbleed count and location were associated with an increased risk for cognitive impairment and dementia. They evaluated a prospective population-based study set in the general community, and assessed the presence, number, and location of microbleeds at baseline (August 2005 to December 2011) on brain MRI in 4841 participants 45 years or older. Trained research physicians, blinded to clinical data, reviewed the MRs. Cerebral microbleeds were defined as small, round to ovoid areas of focal signal loss on T2- weighted images. Participants underwent neuropsychological testing at 2 time points approximately 6 years apart, and were also followed up for incident dementia. 3257 participants underwent baseline and follow-up cognitive testing. Microbleed prevalence was 15.3%. The presence of more than 4 microbleeds was associated with cognitive decline. The presence of microbleeds was associated with an increased risk for dementia after adjustment for age, sex, and educational level, including Alzheimer dementia.
The strengths of this study, according to the authors, is the longitudinal population based design with a large sample size, the use of an extensive neuropsychological test battery, and the virtually complete screening for incident dementia. Limitations include multiple statistical tests, increasing the chance of type I errors. Second, selection bias may have influenced the results, because healthier people without subjective memory complaints were more likely to receive follow-up cognitive testing. Most importantly perhaps, the microbleed number may not reflect the true biological number because microbleed detection strongly depends on technical imaging methods used. T2W images were used, and as we know, SWI is far superior for the detection of these lesions.
Manoso MW, Moore TA, Agel J, Bellabarba C, Bransford RJ. Floating
Austein F, Riedel C, Kerby T, et al. Comparison of Perfusion CT Software to Predict the Final Infarct Volume After Thrombectomy. Stroke. 2016 doi:10.1161/STROKEAHA.116.013147.
The purpose of the study was to determine the accuracy of different commercial perfusion CT software packages to predict the final infarct volume (FIV) after mechanical thrombectomy. Packages evaluated included 1) Philips Brain CT Perfusion Package, Philips Healthcare, The Netherlands, 2) Siemens (Syngo Volume Perfusion CT Neuro, Siemens Healthcare, Erlangen, Germany, and 3) RAPID (iSchemaView Inc, Menlo Park, CA). CTP data from 147 mechanically recanalized acute ischemic stroke patients were postprocessed. Ischemic core and final infarct volume were compared about thrombolysis in cerebral infarction (TICI) score and time interval to reperfusion. Final infarct volume was measured at follow-up imaging between days 1 and 8 after stroke. Significant differences were found between the packages about over- and underestimation of the ischemic core, with RAPID best-predicting hypoperfusion volume in nonsuccessfully recanalized patients. They conclude that this software package overestimated the final infarct volume to a significantly lower degree and estimated a malignant mismatch profile less often than other software.
Tan BYQ, Wan-Yee K, Paliwal P, et al. Good Intracranial Collaterals Trump Poor Alberta Stroke Program Early CT Score for Intravenous Thrombolysis in Anterior Circulation Acute Ischemic Stroke. Stroke. 2016 doi:10.1161/STROKEAHA.116.013879.
As a nice background and reference to describe the various collateral scoring systems, see: Yeo et al, Assessment of Intracranial Collaterals on CT Angiography in Anterior Circulation Acute Ischemic Stroke, AJNR 2015.
The authors evaluated the prognostic effect of the collateral circulation in patients with thrombolysed acute ischemic stroke who have large early infarct sizes as indicated by low ASPECTS score. They stratified patients using ASPECTS into 2 groups: large volume infarcts (ASPECTS≤ 7 points) and small volume infarcts (ASPECTS 8–10). They also evaluated a third group …