Synthetic MRI for Clinical Neuroimaging: Results of the Magnetic Resonance Image Compilation (MAGiC) Prospective, Multicenter, Multireader Trial

Editor’s Choice

The authors performed a prospective multireader, multicase noninferiority trial of 1526 images read by 7 blinded neuroradiologists with prospectively acquired synthetic and conventional brain MR imaging case-control pairs from 109 subjects with neuroimaging indications. Each case included conventional T1- and T2-weighted, T1 and T2 FLAIR, and STIR and/or proton density and synthetic reconstructions from multiple-dynamic multiple-echo imaging. Images were randomized and independently assessed. Overall synthetic MR imaging quality was similar to that of conventional proton-density, STIR, and T1- and T2-weighted contrast views across neurologic conditions. Artifacts were more common in synthetic T2 FLAIR, but were readily recognizable and did not mimic pathology.

Differentiation of Enhancing Glioma and Primary Central Nervous System Lymphoma by Texture-Based Machine Learning

Fellows’ Journal Club

The authors evaluated the diagnostic performance of a machine-learning algorithm by using texture analysis of contrast-enhanced T1-weighted images for differentiation of primary central nervous system lymphoma (n=35) and enhancing glioma (n=71). The mean areas under the receiver operating characteristic curve were 0.877 for the support vector machine classifier; 0.878 for reader 1; 0.899 for reader 2; and 0.845 for reader 3. They conclude that support vector machine classification based on textural features of contrast-enhanced T1WI is noninferior to expert human evaluation in the differentiation of primary central nervous system lymphoma and enhancing glioma.

Heterogeneity of Cortical Lesion Susceptibility Mapping in Multiple Sclerosis

Editor’s Choice

The authors characterized the susceptibility mapping of cortical lesions in patients with MS (n=36) and compared it with neuropathologic observations (n=16). Neuropathologic analysis revealed the presence of an intense band of microglia activation close to the pial membrane in subpial cortical lesions or to the WM border of leukocortical cortical lesions. The quantitative susceptibility mapping analysis revealed 131 cortical lesions classified as hyperintense; 33, as isointense; and 84, as hypointense. They conclude that cortical lesion susceptibility maps are highly heterogeneous, even at individual levels and that the quantitative susceptibility mapping hyperintensity edge found in proximity to the pial surface might be due to the subpial gradient of microglial activation.

Journal Scan – This Month in Other Journals, June 2017

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.

3

AOSpine Masters Series, Volume 8: Back Pain

Roberto Vialle L, ed. Wang JC, Lamartina C, guest eds. AOSpine Masters Series, Volume 8: Back Pain. Thieme; 2016; 230 pp; 133 ill; $119.99

Cover of Roberto Vialle

AOSpine Masters Series is a collection of 10 volumes covering various topics of the spine. This review will cover Volume 8: Back Pain. One of the most common chief complaints encountered by our family physicians and orthopedic surgeons is back pain. At times, treating back pain is very challenging to our healthcare providers and places a significant social and economic burden on our healthcare system. This book reports that the prevalence of back pain ranges from 70–85%.

This publication is organized into 16 chapters covering a broad range of topics that include social aspects, physical exam, imaging, and treatment. There are also specific chapters dedicated to specific pathology, including that of the sacroiliac joints, myopathies, neuromuscular disease, and infection. Additional chapters discuss back pain in pediatric and adult populations.  Within each chapter, the subtopics are clearly identified and tables are nicely labeled. One neat feature of each chapter is the “pearls and pitfalls,” which provides bolded teaching points.

The chapter on imaging provides a broad overview of indications, imaging techniques, and modalities available for back pain. The chapter provides a few pictorial examples of pathology affecting the spine.  The imaging discussed in this chapter would be useful for the general practitioner, as it explains the algorithm behind radiographic work-up of back pain.  This chapter also further explains the pros and cons of imaging modalities such as plain films and MRI.  The images are of good size and quality.

At the end of each chapter, the authors cite the references used, making it easy to correlate the chapter content. The majority of the references are from peer-reviewed journals. One good feature is the authors’ highlighted “5 …

Intraforaminal Location of Thoracolumbar Radicular Arteries Providing an Anterior Radiculomedullary Artery Using Flat Panel Catheter Angiotomography

Fellows’ Journal Club

Ninety-four flat panel catheter angiotomography acquisitions obtained during the selective injection of intersegmental arteries providing an anterior radiculomedullary artery were reviewed. The location of radicular arteries could be ascertained in 78/94 flat panel catheter angiotomography acquisitions. Fifty-three acquisitions (67.9%) were on the left side, and 25 (32.1%), on the right, between T2 and L3. The arteries were found in the anterosuperior quadrant in 75 cases (96.2%), in the posterosuperior quadrant in 2 (2.6%), and in the anteroinferior quadrant in 1(1.3%). Needle placement in the anterosuperior quadrant (subpedicular approach) should be avoided during transforaminal epidural steroid injection. The authors advocate the posterolateral approach that allows placing the needle tip away from the documented position of ARMA contributors within the neural foramen, reducing the risk of intra-arterial injection or injury to the spinal vascularization.

Hindbrain Herniation in Chiari II Malformation on Fetal and Postnatal MRI

Editor’s Choice

The authors examined the neuroimaging findings with a focus on hindbrain herniation and ventricular size in fetuses with open spinal dysraphism and compared them with postnatal imaging features in groups undergoing prenatal-versus-postnatal repair. Thirty-two of 102 (31.3%) fetuses underwent in utero repair of open spinal dysraphism; 68.6% (70/102) underwent postnatal repair. Of those who underwent prenatal repair 81.3% (26/32) had resolved cerebellar ectopia postnatally. Of those who had severe cerebellar ectopia (grade 3) that underwent postnatal repair, 65.5% (36/55) remained grade 3, while 34.5% (19/55) improved to grade 2. They conclude that most fetuses who undergo in utero repair have resolved cerebellar ectopia postnatally.

Clinical and Imaging Characteristics of Diffuse Intracranial Dolichoectasia

Fellows’ Journal Club

The authors retrospectively reviewed a consecutive series of patients with diffuse intracranial dolichoectasia and compared demographics, vascular risk factors, additional aneurysm prevalence, and clinical outcomes with a group of patients with vertebrobasilar dolichoectasia. Twenty-five patients had diffuse intracranial dolichoectasia, and 139 had vertebrobasilar dolichoectasia. Patients with diffuse intracranial dolichoectasia were older than those with vertebrobasilar dolichoectasia and had a higher prevalence of abdominal aortic aneurysms, other visceral aneurysms, and smoking history. Patients with diffuse intracranial dolichoectasia were more likely to have aneurysm growth. They conclude that the natural history of patients with diffuse intracranial dolichoectasia is significantly worse than that in those with isolated vertebrobasilar dolichoectasia.

Risk of Thrombus Fragmentation during Endovascular Stroke Treatment

Editor’s Choice

The authors evaluated the potential relationship between thrombus histology and clot stability in 85 patients with anterior circulation stroke treated with thrombectomy. The number and location of emboli after retrieving the primary thrombus, the number of maneuvers, and TICI scores were evaluated. H&E and neutrophil elastase staining of retrieved clots was performed. An inverse correlation between maneuvers required for thrombus retrieval and the number of distal and intermediate emboli was observed. Younger patients were at higher risk for periprocedural thrombus fragmentation. Bridging thrombolysis tended to be associated with fewer maneuvers but more emboli. They conclude that younger age, easy-to-retrieve thrombi, and bridging thrombolysis may be risk factors for periprocedural thrombus fragmentation. Higher neutrophil levels in the thrombus tissue were related to an increased risk of periprocedural thrombus fragmentation.

Fundamentals of Neurology: An Illustrated Guide, 2nd Edition

Mattle H, Mumenthaler M. Fundamentals of Neurology: An Illustrated Guide. 2nd ed. Thieme; 2017; 456 pp; 567 ill; $79.99

Cover of Mattle and Mumenthaler

Fundamentals of Neurology: An Illustrated Guide is an introductory textbook of clinical neurology. It provides a comprehensive overview of common neurologic and muscular disorders, with numerous supporting illustrations that serve to further clarify the content of this book. The intended audiences are medical students, residents, and practicing clinicians. Indeed, the textbook’s format, concise language, and straightforward illustrations will appeal to physicians of all training levels.

The textbook’s organization is easy to follow, starting from the first page where each chapter is listed and assigned a color that is used for the remainder of the book to designate the corresponding pages of the chapter. Furthermore, the material of each chapter is divided in a way that is easy to digest through the use of sections, which begin by summarizing the key points, and subsections, which have the important ideas highlighted. This approach allows the reader to use the textbook either for detailed studying or for a quick reference. Moreover, the tables, diagrams, and radiologic images are of high quality and are well annotated. In fact, if time is a limiting factor, the reader can still gain a strong understanding of the most important information by just reviewing the provided illustrations.

The textbook’s content primarily provides a clinical approach to understanding various neurologic disorders, with only a superficial focus on diagnostic radiology, especially when compared with more well-known textbooks written for the field of neuroradiology. While the initial chapters concentrate on techniques for obtaining a good patient history and physical exam, as well as ordering appropriate ancillary tests, the second half of the book discusses symptoms and common neurologic disorders in a way that neuroradiologists will also find relevant. For example, there …