ICYMI: July-August 2015 News Digest: Fetal Neuroimaging

Guest Editors

Thierry A.G.M Huisman and Andrea Poretti

Section of Pediatric Neuroradiology, Division of Pediatric Radiology, Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA

Summary

socialIn recent years, significant and continuous development of fetal MR imaging has revolutionized prenatal diagnosis of congenital and acquired brain abnormalities. Procedures that were once time-consuming and placed the mother and fetus at some risk have been made safer and more convenient thanks to developments such as ultrafast MR sequences, which are capable of producing high-resolution anatomic and functional images of the fetus. Furthermore, when ultrasonography (US) — still the primary imaging modality for studying the fetal brain — cannot provide a sufficiently detailed evaluation, fetal brain MRI has emerged as a crucial tool for confirming, correcting, and completing diagnoses made via US of complex pathologies in the fetal CNS. In this edition, 5 authors discuss their research.

Read the full introduction . . .

Commenting Authors

 … Continue reading >>

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AJNR Invites Readers to Share Art

The “Perspectives” section of AJNR will transition this summer to showcase the creative and artistic talents of our readers. The Journal invites you to submit your original drawings, illustrations, or photographs, along with appropriate explanatory information, for consideration of publication within this section.

Please forward electronic images via e-mail to: khalm@asnr.org or request a file transfer link. Accepted images will need to be a minimum resolution of 300 dpi at 6.5 inches wide. Smaller files can be sent for initial review.… Continue reading >>

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Neurosurgery Knowledge Update: A Comprehensive Review

Harbaugh RE, Shaffrey C, Couldwell WT, Berger MS, eds. Neurosurgery Knowledge Update: A Comprehensive Review. Thieme; 2015; 984 pp; 321 ill; $249.99

harbaugh-neurosurg-knowledge_coverIn 157 chapters, each dealing with a specific disease or set of similar diseases, the editors (Drs. Harbaugh, Shaffrey, Couldwell, and Berger) and contributors (289) have put together topics that we deal with nearly every day. They do that in an interesting and provocative manner so that a case is presented along with the images. The reader is then asked to answer a number of multiple choice questions (4 to 10). Following this, a couple of pages are devoted in general to a description of the abnormality, including clinical presentation imaging evaluation, surgical/non-surgical treatment, the answers to the questions, and a summary. While the book was clearly written with the American Board of Neurological Surgery (ABNS) and the MOC for the ABNS in mind, this publication has substantial material for the neuroradiologist. It is important that we gain as full appreciation as possible of the concepts neurological surgeons feel are important or critical. Often these do not coincide with what we as radiologists feel are important. This is brought to the forefront when one attempts to answer the questions put to the reader. A challenge to all neuroradiologists would be to go from chapter to chapter and determine their own proportion of correct answers. To be familiar with what exactly neurosurgeons are expected to know is helpful when presenting at or attending joint neurosurgical/imaging conferences.

There are a variable number of chapters within each section and subsection. The major sections are:

  • Cerebrovascular
  • Functional Neurosurgery
  • Epilepsy
  • Movement Disorder
  • Chronic Pain
  • Pediatrics
  • Spine Peripheral Nerves
  • Trauma and Critical Care
  • Tumors/Neuro-oncology

Clearly, this 984-page hardcover does not cover every issue that a neurosurgeon faces, and does not cover all the … Continue reading >>

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Acute Invasive Fungal Rhinosinusitis: A Comprehensive Update of CT Findings and Design of an Effective Diagnostic Imaging Model

Fellows’ Journal Club Editor’s Comment

Two blinded neuroradiologists retrospectively graded 23 prespecified imaging abnormalities in the craniofacial region on CT examinations from 42 patients with pathology-proven acute invasive fungal rhinosinusitis and 42 control patients. A 7-variable model (periantral fat, bone dehiscence, orbital invasion, septal ulceration, pterygopalatine fossa, nasolacrimal duct, and lacrimal sac) was synthesized on the basis of multivariate analysis. The presence of abnormality involving a single variable in the model had an 87% positive predictive value, 95% negative predictive value, 95% sensitivity, and 86% specificity.

Abstract

Examples of established findings in AIFR. A, Axial CT image shows unilateral mucosal thickening involving the right maxillary sinus (asterisk) with soft-tissue infiltration of the right anterior periantral fat (arrow) and the posterior periantral fat (arrowhead). B, Axial image in a different patient shows unilateral right nasal cavity (white asterisk) and maxillary sinus (black asterisk) mucosal thickening. Soft-tissue infiltration through the right sphenopalatine foramen and pterygopalatine fossa (arrowhead) is seen, as well as involvement of the right posterior periantral fat (arrow). C, Coronal CT in a third patient illustrates orbital involvement of AIFR with subtle infiltration of the right medial and inferior extraconal orbital fat (arrowheads), despite the absence of bone erosion. D, Axial CT shows a surgically proved subtle ulceration along the left side of the nasal septum (arrowhead) in a fourth patient.

Background and Purpose

Acute invasive fungal rhinosinusitis carries a high mortality rate. An easy-to-use and accurate predictive imaging model is currently lacking. We assessed the performance of various CT findings for the identification of acute invasive fungal rhinosinusitis and synthesized a simple and robust diagnostic model to serve as an easily applicable screening tool for at-risk patients.… Continue reading >>

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Improving Multiple Sclerosis Plaque Detection Using a Semiautomated Assistive Approach

Editor’s Choice Editor’s Comment

The authors evaluated and validated a semiautomated software platform to facilitate detection of new lesions and improved MS lesions. Two neuroradiologists retrospectively assessed 161 MR imaging comparison study pairs acquired between 2009 and 2011. More comparison study pairs with new lesions and improved lesions were recorded by using the software compared with original radiology reports.

Abstract
Annotated capture of the software reporting screen. A, Axial FLAIR with superimposed change map shows the new occipital white matter lesion in orange. Coregistered and resectioned FLAIR sequences comparing axial of new study (B) with axial of old study (C); and sagittal of new study (E) with sagittal old study (F)—thus confirming that the lesion is real and consistent with a new demyelinating plaque. D, Each lesion is marked with 3D coordinates.

Annotated capture of the software reporting screen. A, Axial FLAIR with superimposed change map shows the new occipital white matter lesion in orange. Coregistered and resectioned FLAIR sequences comparing axial of new study (B) with axial of old study (C); and sagittal of new study (E) with sagittal old study (F)—thus confirming that the lesion is real and consistent with a new demyelinating plaque. D, Each lesion is marked with 3D coordinates.

Background and Purpose

Treating MS with disease-modifying drugs relies on accurate MR imaging follow-up to determine the treatment effect. We aimed to develop and validate a semiautomated software platform to facilitate detection of new lesions and improved lesions.

Materials and Methods

We developed VisTarsier to assist manual comparison of volumetric FLAIR sequences by using interstudy registration, resectioning, and color-map overlays that highlight new lesions and improved lesions. Using the software, 2 neuroradiologists retrospectively assessed MR imaging MS comparison study pairs acquired between 2009 and 2011 (161 comparison study pairs met the study inclusion criteria). Lesion detection and reading times were recorded. We tested inter- and intraobserver agreement and comparison with original clinical reports. Feedback was obtained from referring neurologists to assess the potential clinical impact.

Results

More comparison study pairs with new lesions (reader 1, n = 60; reader 2, n= 62) and improved lesions (reader 1, n = 28; reader 2, n = 39) were recorded

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Top 3 Differentials in Neuroradiology: A Case Review

O’Brien Sr WT. Top 3 Differentials in Neuroradiology: A Case Review. Thieme; 2015; 624 pp; 697 ill; $129.99

obrien-differentials-coverWhile many great neuroradiology texts exist, Top 3 Differentials in Neuroradiology offers a unique and engaging approach to learning and reviewing neuroradiology. A total of 300 interesting cases are presented, organized into 3 sections: Brain, Head and Neck, and Spine. While, as the title suggests, most cases offer a differential diagnosis, each section concludes with approximately 30 “Aunt Minnies” for which no differential is offered or needed. For each case, one page has the images (without arrows), history, and, off to the side, a concise description of the key imaging findings. On the opposing page the “Key Imaging Finding” is clearly stated so that the reader knows what the discussion and differential will be referring to. This is followed by “Top 3 Differential Diagnoses”. After each diagnosis, there is a description, which is concise yet laced with imaging and clinical pearls. Most cases provide additional differentials (with descriptions), which are less likely but should also be considered. The final diagnosis is then given. Sometimes, this final diagnosis is somewhat of a surprise, underscoring the need for a differential diagnosis in most cases we see. The case is concluded with 3–4 bulletpoint ‘Pearls’.

The reader can and should approach each case as if it were a case they were reading or consulted on and try to formulate a differential based on the imaging findings and provided history. The provided cases are interesting, and the images are high-quality. Dr. O’Brien is able to near perfectly walk the line between too little and too much information/discussion for each case. All sections of the book are strong.

Overall, this book is highly recommended for senior radiology residents, neuroradiology fellows, practicing radiologists, and non-radiology clinicians who … Continue reading >>

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Fellows’ Journal Club Recap: Provocative Discography and Lumbar Injury

Review by: Dr. James Fernandez and Dr. Sepand Salehian

http://www.ajnr.org/site/Podcasts/August2015FJC.mp3

Click to listen to the accompanying podcast (discussion of this article begins at 19:15)

The Spine Journal, published June 29, 2015, entitled: Does provocative discography cause clinically important injury to the lumbar intervertebral disc? A ten-year matched cohort study

A group of 75 asymptomatic or minimally symptomatic for low back pain were enrolled in a study for provocative discography involving L3-S1 disc spaces.  The subjects were recruited from one of three patient pools: those having documented cervical disease, subjects with previous lumbar disc herniation with complete symptom resolution, and subjects with no history of cervical or lumbar disc illness but with a history of somatization disorder.  Another 75 matched subjects from the same subject pools who did not have discography performed were utilized as control subjects.

After the 75 subjects underwent discography, both groups were followed for up to 10 years. Primary outcomes measured were any reported imaging or surgical intervention; and secondary outcomes measured any low back pain events occurring 6 months prior to the interview, serious low back pain episodes, disability due to back pain, or medical visits for evaluation and treatment of back pain.

In terms of primary outcome measures, as defined by this study, the results were reported as follows:

By 10-years follow-up, there were 16 lumbar surgeries performed in 11 subjects in the discography group and 4 surgeries in 3 subjects in the control group; resulting in a number needed to harm value (NNH value) of 7.3.

At 10 years after enrollment, 21 discography subjects and 11 control subjects had new CT or MRI evaluations for the clinical evaluation of low back pain and/or lower extremity radiculopathy. Based on these data, the number needed to harm (NNH) for 12 provocative lumbar discography with … Continue reading >>

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Normal Pressure Hydrocephalus

Fritsch MJ, Kehler U, Meier U. Normal Pressure Hydrocephalus. 1st ed. Thieme; 2014; 204 pp; 435 ill; $149.99

Normal Pressure Hydrocephalus-FritschAs a reversible and underdiagnosed brain disorder, normal pressure hydrocephalous (NPH) deserves greater awareness and recognition among the various medical disciplines that care for elder patients. The book NPH Pathophysiology Diagnosis and Treatment by Fritsch, Kehler, and Meirer is a well-organized and easy-to-follow overview of NPH and, therefore, a useful resource for becoming informed and aware of the complexity associated with this condition. The 144 high-quality illustrations and figures well contribute to the overall outstanding clarity in which the material is presented. While this book started as a course for neurosurgeons, to address the underrepresentation of NPH in the neurosurgical literature, it covers a wide perspective and the different aspects associated with NPH, from the epidemiology and the pathophysiology through differential diagnosis, to treatment, including surgical techniques and a detailed in-depth review of the ever-evolving CSF shunt and valve technology.

This book is a valuable reference for clinicians of various disciplines that are involved in either identifying this challenging condition by making the correct differential diagnosis or those involved in treating and managing the care of NPH patients. This book provides a good starting point for those who are interested in a more in-depth knowledge of NPH. Three of the 17 chapters in this book are the more relevant for the neuroradiology audience. These are the chapters that cover noninvasive and invasive diagnostic work-up as well as imaging. The imaging chapter is relatively concise and it provides mainly basic information on the utilization of different imaging modalities in the diagnosis of NPH. Surprisingly, the past and current role of nuclear medicine in NPH has not been covered. Overall, the topic of imaging in NPH is challenging due to the lack of … Continue reading >>

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Challenges in Identifying the Foot Motor Region in Patients with Brain Tumor on Routine MRI: Advantages of fMRI

Fellows’ Journal Club Editor’s Comment

Thirty-five attending-level raters evaluated 14 brain tumors involving the frontoparietal convexity. Raters identified the location of the foot motor homunculus and determined whether the tumor involved the foot motor area and/or motor cortex by using anatomic MR imaging. Seventy-seven percent of the time raters correctly identified whether the tumor was in the foot motor cortex. Raters with fMRI experience were significantly better than raters without experience at foot motor fMRI centroid predictions.

Abstract
Axial T1-weighted without (A) or with (B) coregistered functional MR images obtained during a bilateral finger-tapping and foot motor paradigm. The raters were asked to identify the foot motor homunculus solely on the basis of the anatomic images (A) without the benefit of fMRI (B). fMRI places the extra-axial lesion just posterior to the primary motor gyrus, including the foot motor portion of the motor homunculus. Edema extends to involve both the precentral and postcentral gyri. The average arrow placement from the foot motor center was 16 mm in those with fMRI experience and 23 mm in those without it. A higher percentage of raters with fMRI experience than those without it placed the arrow in the motor gyrus (65% versus 50%). Eighteen percent of raters with fMRI experience correctly identified the tumor as not being located in the foot motor cortex, while 33% of raters without fMRI experience did so. Last, 35% and 39% of raters with and without fMRI experience, respectively, correctly identified the tumor as not being located in the motor gyrus. Most of the incorrect arrow placements were due to the arrow being placed in a gyrus posterior to the motor gyrus.

Axial T1-weighted without (A) or with (B) coregistered functional MR images obtained during a bilateral finger-tapping and foot motor paradigm. The raters were asked to identify the foot motor homunculus solely on the basis of the anatomic images (A) without the benefit of fMRI (B). fMRI places the extra-axial lesion just posterior to the primary motor gyrus, including the foot motor portion of the motor homunculus. Edema extends to involve both the precentral and postcentral gyri. The average arrow placement from the foot motor center was 16 mm in those with fMRI experience and 23 mm in those without it. A higher percentage of raters with fMRI experience than those without it placed the arrow in the motor gyrus (65% versus 50%). Eighteen percent of raters with fMRI experience correctly identified the tumor as not being located in the foot motor cortex, while 33% of raters without fMRI experience did so. Last, 35% and 39% of raters with and without fMRI experience, respectively, correctly identified the tumor as not being located in the motor gyrus. Most of the incorrect arrow placements were due to the arrow being placed in a gyrus posterior to the motor gyrus.

Background and Purpose

Accurate localization of the foot/leg motor homunculus is essential because iatrogenic damage can render a … Continue reading >>

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Emergency Imaging: A Practical Guide

Baxter AB. Emergency Imaging: A Practical Guide. Thieme; 2015; 580 pp; 1727 ill; $99.99

Baxter_Emergency Imaging_4c.inddIntended for radiology residents who are about to cover the ER/Trauma area for the first time, and for those who are currently doing so, this 580-page book covers a large number of abnormalities that are likely to be encountered.

Like most books of this nature, the findings are obvious on the displayed images. As we all know, the issue is not often “what is the diagnosis?” but rather “is there an abnormality?” This book (along with virtually all others) does not test or challenge the reader to find/uncover the abnormality. An educational contribution along those lines would, in order to be effective, hhave to be an scrollable set of images online, in which the reader was challenged to find and make the diagnosis.

Those comments aside, this book displays images on the left-hand side and the diagnosis on the right-hand side so that the answer really is never withheld from the reader. Nonetheless, the images are proper and the accompanying text is adequate. The brain, head and neck, and spine are covered in nearly 200 pages (⅓ of the book).

After an introduction of 8 pages, the following are the sections covered: Brain, Head and Neck, Spine, Chest, Abdomen and Pelvis, Musculoskeletal, Pediatrics. As an exercise, it is valuable to go through each set of images and read the accompanying legend and text. As expected, the images are dominated by CT and plain film. Only of few scattered sonograms, and no MRIs, are shown.

This would be a worthwhile text to place in the ER radiology area so all those rotating through can refer to the book as needed.… Continue reading >>

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Hyperintense Vessels on FLAIR: Hemodynamic Correlates and Response to Thrombolysis

Editor’s Choice Editor’s Comment

The authors evaluated 62 consecutive patients with ischemic stroke with proven vessel occlusion with MRI before and within 24 hours of treatment and defined a hypoperfusion intensity ratio (volume with severe/mild hypoperfusion [time-to-maximum ≥ 8 seconds / time-to-maximum ≥ 2 seconds]). Patients with extensive hyperintense vessels on FLAIR (>4 sections) had higher NIHSS scores, larger baseline lesion volumes, higher rates of perfusion-diffusion mismatch, and more severe hypoperfusion intensity ratio.

Abstract
MR imaging (left-to-right: acute FLAIR, acute DWI, acute Tmax, dichotomized Tmax, follow-up DWI) of patients with middle cerebral artery occlusions (M1). Patient A (82 years of age; baseline NIHSS score, 13; baseline lesion volume, 1.4 mL; HIR, 0.031; recanalization to Thrombolysis in Myocardial Infarction 2 following treatment; absolute infarct growth, 3.3 mL) had FLAIR hyperintense vessels on 3 sections (FHV ≤ 4; not visible on the depicted section) and patient B (76 years of age; baseline NIHSS score, 23; baseline lesion volume, 63.8 mL; HIR, 0.53; no recanalization following treatment [Thrombolysis in Myocardial Infarction, 0]; absolute infarct growth, 80.2 mL) had FHV on 8 sections (arrows; FHV > 4).

MR imaging (left-to-right: acute FLAIR, acute DWI, acute Tmax, dichotomized Tmax, follow-up DWI) of patients with middle cerebral artery occlusions (M1). Patient A (82 years of age; baseline NIHSS score, 13; baseline lesion volume, 1.4 mL; HIR, 0.031; recanalization to Thrombolysis in Myocardial Infarction 2 following treatment; absolute infarct growth, 3.3 mL) had FLAIR hyperintense vessels on 3 sections (FHV ≤ 4; not visible on the depicted section) and patient B (76 years of age; baseline NIHSS score, 23; baseline lesion volume, 63.8 mL; HIR, 0.53; no recanalization following treatment [Thrombolysis in Myocardial Infarction, 0]; absolute infarct growth, 80.2 mL) had FHV on 8 sections (arrows; FHV > 4).

Background and Purpose

Hyperintense vessels on baseline FLAIR MR imaging of patients with ischemic stroke have been linked to leptomeningeal collateralization, yet the ability of these to maintain viable ischemic tissue remains unclear. We investigated whether hyperintense vessels on FLAIR are associated with the severity of hypoperfusion and response to thrombolysis in patients treated with intravenous tissue-plasminogen activator.

Materials and Methods

Consecutive patients with ischemic stroke with an MR imaging before and within 24 hours of treatment, with proved vessel occlusion and available time-to-maximum maps were included (n = 62). The severity of hypoperfusion was characterized on the basis of the hypoperfusion intensity ratio (volume with severe/mild hypoperfusion [time-to-maximum ≥ 8 seconds / time-to-maximum ≥ 2

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Dynamic Reconstruction of the Spine

Kim DH, Sengupta DK, Cammis Jr FP, Yoon DH, Fessler RG, eds. Dynamic Reconstruction of the Spine. 2nd ed. Thieme; 2015; 480 pp; 661 ill; $249.99

Dynamic Reconstruction of the Spine-KimFor those radiologists who are part of a large spine surgery center where significant spine reconstructive surgery is performed, this 450-page hardcover book edited by Drs. Kim, Sengupta, Cammisa, Yoon, and Fessler could serve as an occasional reference in understanding the rationale of instrumented spine procedures.

Over 100 authors contribute to this authoritative text and allows one to see in imaging and in drawings what actually is being done and the reasoning behind the surgery. As we all know, how patients with spine disorders are treated varies from surgeon to surgeon, from geographic area to geographic area, and, as skeptics may say, from reimbursement to reimbursement. Those many factors, be as they may, still require that neuroradiologists have some basic understanding of the biomechanics, material, and surgical approach used. Aside from sporadic papers in the radiology literature, information on topics as seen here is difficult to find in our literature. Nonetheless, we are faced with imaging showing the varying types of instrumentation on nearly a daily basis. Like many other topics in medicine, once a subject is appreciated in some depth, interpretation of the associated images become more interesting and of greater value to the surgeon.

The book is structured along the following lines or parts:

  • Motion Preservation of the Spine (3 chapters)
  • Clinical Biomechanics of the Spine (8 chapters)
  • Restoration of the Cervical Movement Segment (11 chapters)
  • Restoration of the Lumbar Movement Segment (34 chapters)
  • Advancements in Lumbar Motion Preservation (6 chapters)

While many chapters are not particularly germane to radiology, such as those which delve deeply into biomechanics, others are, such as those on complications; indications for disc arthroplasty; nomenclature and … Continue reading >>

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