Editor’s Choices
Apolipoprotein E ε4 Does Not Modulate Amyloid-β–Associated Neurodegeneration in Preclinical Alzheimer Disease • R.S. Desikan, L.K. McEvoy, D. Holland, W.K. Thompson, J.B. Brewer, P.S. Aisen, O.A. Andreassen, B.T. Hyman, R.A. Sperling, A.M. Dale, and for the Alzheimer’s Disease Neuroimaging Initiative
These authors investigated the relationship between amyloid-β, phosphorylated tau, and apolipoprotein E in preclinical Alzheimer disease in 170 patients and controls who had serial imaging up to 3.5 years after the initial study. Global volumes as well as volumes in brain regions known to be involved in the chronic stages of the disease were assessed. Their results led them to propose that atrophy rates are primarily influenced by apolipoprotein E via amyloid-β mechanisms and that amyloid-β -associated neurodegeneration occurs only in the presence of phosphorylated tau.
Blood-Brain Barrier Disruption after Cardiac Surgery • J.G. Merino, L.L. Latour, A. Tso, K.Y. Lee, D.W. Kang, L.A. Davis, R.M. Lazar, K.A. Horvath, P.J. Corso, and S. Warach
To shed light on brain complications occurring after heart surgery, the authors assessed BBB disruption and DWI findings in half of their patients by imaging at 24 hours after surgery and 24–48 hours later. Additionally, postcontrast T1 images were obtained postoperatively at 2–4 days in the other half of the patients. Almost half the patients undergoing cardiac surgery had evidence of BBB abnormalities and three-quarters showed acute lesions on DWI after surgery. BBB disruption is more prevalent in the first 24 hours after surgery. These findings suggest that MR can be used as an imaging biomarker to assess therapies that may protect the BBB in patients undergoing heart surgery.
Probabilistic Radiographic Atlas of Glioblastoma Phenotypes • B.M. Ellingson, A. Lai, R.J. Harris, J.M. Selfridge, W.H. Yong, K. Das, W.B. Pope, P.L. Nghiemphu, H.V. Vinters, L.M. Liau, P.S. Mischel, and T.F. Cloughesy
Images from over 500 patients with glioblastoma were used to build location atlases corresponding to genetic and biologic abnormalities as well as prognosis based on age. Most glioblastomas grew into the periventricular regions adjacent to the subventricular zone. MGMT promoter methylated tumors occurred more frequently in the left temporal lobe in young patients, in IDH1 mutant tumors, in those having the proneural gene expression subtype, and in tumors lacking loss of PTEN that occurred most frequently in the frontal lobe. MGMT methylated tumors with IDH1 mutation tended to occur in the left frontal lobe. EGFR amplified and EGFR variant 3-expressing tumors were found most frequently in the left temporal lobe. Tumors in the left temporal lobe were associated with favorable response to radiochemotherapy and increased survival.
Fellows’ Journal Club
Impaired Default Mode Network on Resting-State fMRI in Children with Medically Refractory Epilepsy • E. Widjaja, M. Zamyadi, C. Raybaud, O.C. Snead, and M.L. Smith
This article explores the possibility that the default mode network as seen on resting state fMRI is abnormal in children with medically refractory epilepsy as it is in adults. Studies in 11 patients showed abnormal default mode networks with decreased connectivity but no correlations with age of seizure onset, duration of epilepsy, number of medications, seizure frequency, or IQ.
Evaluation of an Intravenous-Endovascular Strategy in Patients with Acute Proximal Middle Cerebral Artery Occlusion • J.-F. Vendrell, R. Mernes, N. Nagot, D. Milhaud, K. Lobotesis, V. Costalat, P. Machi, I.L. Maldonado, C. Riquelme, C. Arquizan, and A. Bonafe
Here, the safety and efficacy of mechanical thrombectomy after intravenous therapy failure were assessed in 123 patients with acute MCA occlusions. All patients imaged were within 4.5 hours of onset, had DWI ASPECTS greater than 5, and variable NIHSS scores (8–25). The authors found that mechanical thrombectomy after failure of intravenous thrombolysis improves clinical outcomes at 3 months and could represent an alternative in the management of patients with acute MCA occlusion. Additionally, no symptomatic intracranial hemorrhages were detected in patients treated this way, suggesting this protocol is safe.
Comparison of MR Imaging Findings between Extraligamentous and Subligamentous Disk Herniations in the Lumbar Spine • K.-J. Oh, J.W. Lee, B.L. Yun, S.T. Kwon, K.-W. Park, J.S. Yeom, and H.S. Kang
Extra- and subligamentous lumbar disk herniations are treated differently. These authors utilized 10 criteria in an attempt to establish the exact location of disk herniations with respect to the posterior longitudinal ligament. Extraligamentous herniations showed: 1) spinal canal compromise of more than half its diameter, 2) internal signal difference in the disk, 3) ill-defined disk margins, 4) disruption of the continuous low-signal-intensity line covering the disk, and 5) presence of an internal dark line in the herniated disk. When combined these 5 yield sensitivity, specificity, accuracy, and an odds ratio of 77.3%, 74.5%, 76.1%, and 9.93, respectively.
