Neuroradiology Fellow Research Articles

Multicenter Accuracy and Interobserver Agreement of Spot Sign Identification in Acute Intracerebral Hemorrhage

Rapid, accurate, and reliable identification of the computed tomography angiography spot sign is required to identify patients with intracerebral hemorrhage for trials of acute hemostatic therapy. We sought to assess the accuracy and interobserver agreement for spot sign identification. A total of 131 neurology, emergency medicine, and neuroradiology staff and fellows underwent imaging certification for spot sign identification before enrolling patients in 3 trials targeting spot-positive intracerebral hemorrhage for hemostatic intervention (STOP-IT, SPOTLIGHT, STOP-AUST). Ten intracerebral hemorrhage cases (spot-positive/negative ratio, 1:1) were presented for evaluation of spot sign presence, number, and mimics. True spot positivity was determined by consensus of 2 experienced neuroradiologists. Diagnostic performance, agreement, and differences by training level were analyzed. Mean accuracy, sensitivity, and specificity for spot sign identification were 87%, 78%, and 96%, respectively. Overall sensitivity was lower than specificity (P<0.001) because of true spot signs incorrectly perceived as spot mimics. Interobserver agreement for spot sign presence was moderate (k=0.60). When true spots were correctly identified, 81% correctly identified the presence of single or multiple spots. Median time needed to evaluate the presence of a spot sign was 1.9 minutes (interquartile range, 1.2-3.1 minutes). Diagnostic performance, interobserver agreement, and time needed for spot sign evaluation were similar among staff physicians and fellows. Accuracy for spot identification is high with opportunity for improvement in spot interpretation sensitivity and interobserver agreement particularly through greater reliance on computed tomography angiography source data and awareness of limitations of multiplanar images. Further prospective study is needed.

Intrarater and interrater reliability of the pediatric arteriovenous malformation compactness score in children

Cerebral arteriovenous malformations (AVMs) have a higher postresection recurrence rate in children than in adults. The authors' previous study demonstrated that a diffuse AVM (low compactness score) predicts postresection recurrence. The aims of this study were to evaluate the intra- and interrater reliability of the AVM compactness score. Angiograms of 24 patients assigned a preoperative compactness score (scale of 1-3; 1 = most diffuse, 3 = most compact) in the authors' previous study were rerated by the same pediatric neuroradiologist 9 months later. A pediatric neurosurgeon, pediatric neuroradiology fellow, and interventional radiologist blinded to each other's ratings, the original ratings, and AVM recurrence also rated each AVM's compactness. Intrarater and interrater reliability were calculated using the κ statistic. Of the 24 AVMs, scores by the original neuroradiologist were 1 in 6 patients, 2 in 16 patients, and 3 in 2 patients. Intrarater reliability was 1.0. The κ statistic among the 4 raters was 0.69 (95% CI 0.44-0.89), which indicates substantial reliability. The interrater reliability between the neuroradiologist and neuroradiology fellow was moderate (κ = 0.59 [95%CI 0.20-0.89]) and was substantial between the neuroradiologist and neurosurgeon (κ = 0.74 [95% CI 0.41-1.0]). The neuroradiologist and interventional radiologist had perfect agreement (κ = 1.0). Intrarater and interrater reliability of the AVM compactness score were excellent and substantial, respectively. These results demonstrate that the AVM compactness score is reproducible. However, the neuroradiologist and interventional radiologist had perfect agreement, which indicates that the compactness score is applied most accurately by those with extensive angiography experience.

Facet Joint Signal Change on MRI at Levels of Acute/Subacute Lumbar Compression Fractures

The prevalence of facet joint signal change in acute/subacute lumbar vertebral body compression fractures is unknown. We hypothesized that facet joint signal change on MR imaging is more common in facet joints associated with an acute/subacute lumbar compression fracture than those associated with normal vertebral bodies or ones that have a chronic compression fracture. Three neuroradiologists and a neuroradiology fellow retrospectively graded facet joint inflammatory change on MR imaging in 900 facet joints in 75 patients with at least 1 painful osteoporotic lumbar compression fracture. Facet joint signal change was assessed on T2-weighted images with chemical fat-saturation, STIR images, and/or gadolinium-enhanced T1-weighted images with chemical fat-saturation. Each facet joint from the T12/L1 to L5/S1 level was assessed individually. An overall facet joint signal-change score, which is a composite measure of the grade of signal change for all 4 facet joints associated with a given lumbar vertebral level, was devised, and statistical significance was assessed via Wilcoxon rank sum tests. The overall facet joint signal-change scores were significantly higher at vertebral body levels affected by an acute/subacute compression fracture compared with control levels, which were associated with either normal bodies or chronic compression fractures. Our findings suggest an association between facet joint signal change on MR imaging and acute/subacute lumbar vertebral body compression fractures.

Three-Phase Parathyroid 4-Dimensional Computed Tomography Initial Experience

Multiphase multidetector contrast-enhanced parathyroid CT (4-dimensional computed tomography [4D-CT]) is an emerging tool for evaluating patients with primary hyperparathyroidism. Our goal was to describe the initial performance of 2 inexperienced readers in interpretation of 4D-CT. Twenty-three subjects who received 4D-CT and successful surgical exploration were studied (14 initial and 9 repeat explorations; 15 single-gland disease and 8 multigland disease) A staff neuroradiologist prospectively interpreted all studies, and a neuroradiology fellow retrospectively interpreted all studies; their results were compared with the surgical findings for each side of the neck separately. The prospective readings were 78% accurate overall, 97% accurate in the subset of single-gland disease cases, and 89% accurate in re-exploration cases. There was 91% concordance in interpretation between observers, with κ of 0.83. Initial results after implementation of 4D-CT show high accuracy of interpretation for inexperienced observers, comparable to published data, and high interobserver agreement.

Assessment of an Introductory Cervicocerebral Catheter Angiography Learning Program: A Pilot Study

There is no standardized curriculum currently available at most institutions for establishing procedural competency in trainees performing cervicocerebral angiography. The purpose of this study was to evaluate a simple learning program to supplement the teaching of basic cervicocerebral angiography. An 11-session interactive curriculum was implemented covering anatomic, clinical, and radiographic topics for the novice cervicocerebral angiographer. The target learner was the neuroradiology fellow. Data were gathered regarding fellow comfort level on topics relating to cervicocerebral angiography by using a 5-point Likert scale. Improvement in scores on knowledge-based questions after completion of the curriculum was calculated (McNemar test). Trainee-perceived utility of the program was also recorded by using a 5-point Likert scale. Focus sessions were held at the completion of the curriculum to gather feedback regarding the strengths and weaknesses of the program from participants. Ten subjects were enrolled in this pilot study for 3 years. Topics where participants reported a poor initial comfort level (4 or higher) included selection of injection rates and volumes and reformation of reverse-curve catheters. Trainees demonstrated a statistically significant change in the distribution of scores of 29.3% (49.4%-78.7% correct response rate, P < .0001). The average perceived utility was 1.5 (1 = most useful, 5 = least useful). This simple learning program was a useful adjunct to the training of fellows in diagnostic cervicocerebral angiography, resulting in quantitative improvements in knowledge.

Interpretation Errors in CT Angiography of the Head and Neck and the Benefit of Double Reading

CTA provides high-resolution imaging of the head and neck vasculature but also of the soft tissues and bones. This results in a large volume of information to be interpreted. This study examines interpretation errors with head and neck CTAs and assesses whether double reading reduces miss rates. Consecutive CTAs of the neck and intracranial circulation were retrospectively identified and reviewed for vascular and nonvascular findings by a consensus of 2 neuroradiologists. The results were compared with the official report. Significant discrepancies were considered those that would have influenced follow-up or management. We reviewed 503 studies; 144 were originally reported by a staff neuroradiologist alone, 209 by staff and diagnostic radiology resident, and 150 by staff and neuroradiology fellow. Twenty-six significant discrepancies were discovered in 20 studies, corresponding to 4.0% of studies with at least 1 miss, and an overall miss rate per study of 5.2%. There was at least 1 miss in 6.3% of studies interpreted by a staff neuroradiologist alone, 3.3% by staff and resident, and 2.7% by staff and fellow. The miss rate differences were not statistically significant. The most common misses were small aneurysms (50% of misses). CTA neck and head datasets are now large, and there is a potential for missed findings. Significant discrepancies can occur with a low but not insignificant rate. Arterial pathology accounted for most discrepancies. This study emphasizes the need for careful systematic scrutiny for both vascular and nonvascular pathology regardless of indication. Double reading reduces error rates.

Volume of Neuroradiology Studies Read by Neurologists: Implications for Fellowship Training

The ACGME recognizes radiology's neuroradiology fellowship programs as the pathway to neuroradiology expertise. Members of the American Society of Neuroimaging have called for the expansion of neuroradiology fellowships for neurologists with informal accreditation through the United Council for Neurologic Subspecialties. The aim of this study was to investigate the number of neuroradiologic studies read by neurologists to assess their capacity to support fellowship positions at ACGME training criteria. The numbers of neuroradiologic studies interpreted by radiologists and neurologists in the inpatient and hospital outpatient settings were determined from the CMS Physician/Supplier Procedure Summary Master Files for 1996 to 2008. The ACGME requirements of 1,500 neuroradiologic CT and 1,500 neuroradiologic MR scans per fellow per year were used to calculate the number of fellowship positions that could be supported by each specialty. In 2008, in the inpatient and hospital outpatient setting, radiologists interpreted 9,287,768 (98.3% of the total) and neurologists interpreted 43,107 (0.5% of the total) neuroradiologic examinations on Medicare patients. Per ACGME requirements, on the basis of CT volumes, radiologists could potentially train 4,256 neuroradiology fellows, compared with neurologists' 12 fellows, assuming a single fellow was exposed to every Medicare case. On the basis of MR volumes, radiologists and neurologists could train 1,935 and 16 fellows, respectively. Radiologists are responsible for interpreting the vast majority (98.3%) of neuroradiologic studies. Neurologists have a limited exposure to neuroradiologic CT and MR and could support only 12 fellowship positions by ACGME criteria on the basis of reading available 1996 to 2008 Medicare cases.

Indeterminate Orbital Masses: Restricted Diffusion at MR Imaging with Echo-planar Diffusion-weighted Imaging Predicts Malignancy

To determine whether magnetic resonance (MR) imaging with diffusion-weighted (DW) imaging can help discriminate between radiologically indeterminate benign and malignant orbital masses and to identify optimal apparent diffusion coefficient (ADC) thresholds for such discrimination. Informed consent was waived for this HIPAA-compliant institutional review board-approved retrospective study. Forty-seven orbital masses imaged with echo-planar DW imaging were identified in 47 patients (25 female patients, 22 male patients; average age, 35 years). A fellowship-trained orbital surgeon determined reference-standard diagnoses on the basis of chart review, and a neuroradiology fellow and senior neuroradiologist who were blinded to the diagnoses selected a region of interest for each lesion by consensus. ADC was calculated from signal intensity on DW images obtained with b = 1000 and b = 0 sec/mm(2). Lesion ADC was also compared with that of normal-appearing white matter (ADC ratio). The Student t test was used to compare groups. Receiver operating characteristic analysis was performed. Intraobserver agreement was assessed with a repeat data collection. Malignant lesions had lower ADCs than benign lesions, irrespective of patient age (P < .02) and in adults specifically (P < .05). Lymphomas had lower ADCs than pseudotumors (P < .001). An ADC of less than 1.0 x 10(-3) mm(2)/sec and an ADC ratio of less than 1.2 were optimal for predicting malignancy (sensitivity, 63% for both; specificity, 84% and 90%, respectively; and accuracy, 77% and 81%, respectively). Lymphoma was differentiated from pseudotumor with 100% accuracy (in 16 of 16 cases) by using these values. Infiltrative lesions that were hypointense on T2-weighted images were better characterized with DW imaging than lesions that were hyperintense or well defined. Echo-planar DW MR imaging can help characterize indeterminate orbital masses.

Radiology Report Clarity: A Cohort Study of Structured Reporting Compared With Conventional Dictation

The aim of this study was to determine if radiology residents who use a structured reporting system (SRS) produce reports of greater clarity than residents who use free-text dictation to report cranial MR imaging in patients with clinical suspicion of stroke. This double-cohort study included residents creating reports for 25 cranial MR imaging studies using an SRS in the intervention group and free text in the control group (report n = 1,685). Attending physicians from multiple subspecialties were surveyed seeking clarity ratings of randomly selected reports. Two neuroradiology fellows rated the clarity of 180 of the reports. Clarity ratings were analyzed by using Wilcoxon's signed-rank test for paired data and the Mann-Whitney U test for unpaired data. Forty-three of 95 surveyed physicians returned completed surveys, with mean clarity ratings for SRS (4.9) and free-text (5.1) reports that did not differ significantly. Respondents' comments most often referred to confusing syntax, unfamiliar terms, or format preferences. Fellow raters rated the clarity of SRS reports lower than that of free-text reports (P < .001). The use of an SRS to create MRI reports did not seem to improve or worsen attending physicians' perceptions of report clarity. Experience level may affect clarity-related report preferences. Future SRS should probably include definitions of key terms and be formatted to minimize syntactical errors.

Neuroimaging Evaluation of Non-accidental Head Trauma with Correlation to Clinical Outcomes: A Review of 57 Cases

To review the clinical presentation and neuroimaging findings in patients with high clinical suspicion for non-accidental trauma (NAT) of the head, to investigate associations between imaging findings and long-term neurologic outcome in abused children. A retrospective review of 57 cases of NAT of the head from a single institution was performed. Neuroimaging studies (computed tomography [CT] and magnetic resonance imaging [MRI]) were reviewed by a senior neuroradiologist, a neuroradiology fellow, and a radiology resident. Clinical history and physical findings, including retinal examination, imaging, and follow-up assessment, were reviewed. The mean time between the patient's arrival at the hospital and CT and MRI imaging was 2.9 hours and 40.6 hours, respectively. The most common clinical presentation was mental status changes, seen in 47% of patients. The most common neuroimaging finding was subdural hematoma, seen in 86% of patients. In the 47 patients who underwent both MRI and CT, 1 case of suspected NAT was missed on head CT. CT detected signs of global ischemia in all 11 patients who died (mean time after arrival at the hospital until undergoing CT, 1.1 hours). MRI detected additional signs of injury in patients who developed mild to moderate developmental delay. CT was able to detect evidence of NAT of the head in 56 of 57 abused children included in our cohort and predicted severe neurologic injury and mortality. MRI was useful in detecting additional evidence of trauma, which can be helpful in risk stratification for neurologic outcomes as well in providing confirming evidence of repeated injury.

Neuroradiology Fellowship Match: Year 4 Applicants’ Perceptions

The selection of neuroradiology fellows who will start on July 1, 2005, marked the fourth year in which program directors in neuroradiology used the National Resident Matching Program (NRMP) as the selection modality. The aim of this study was to investigate fellowship candidates' views regarding the match process. A Web survey was distributed electronically to all candidates applying for neuroradiology fellowship positions offered for the July 1, 2005, start date, with questions about the match. One hundred thirteen neuroradiology fellowship candidates responded to the survey, representing 73.9% of the surveyed fellowship pool. Candidates were also allowed to enter their comments regarding the match process via the Web survey. Of the 113 neuroradiology fellowship candidates responding, 75.7% felt that the NRMP system was fair, 86.0% were satisfied with the outcome, 88.8% had matched with one of their top three choices, 54.5% recommended continuing the neuroradiology fellowship match, and 15.5% stated that they experienced violations of the match rules. The main perceived advantages of the match from the candidates' perspectives were the ability to see many programs and explore multiple options, the perception of fairness, and the efficiency of using the match program. The main disadvantages were the cost of applications and traveling, the number of days required to interview, and the perception that the match program favors internal candidates. The majority of fellowship candidates felt that the match system for selection is a fair process and were satisfied with the outcome. However, the perceived disadvantages produced tepid (54.5%) support for the continuation of the match. Program directors in neuroradiology and other radiologic subspecialties should consider the data provided in this article in deciding the future selection process.

Processing and Interpretation Times of CT Angiogram and CT Perfusion in Stroke

To determine the mean time for acquiring computed tomogram perfusion (CTP) and CT angiogram (CTA) images in acute stroke. To determine and compare processing and interpretation times amongst three groups of radiologists with varying degree of expertise: two radiology residents (Group I), two neuroradiology fellows (Group II) and four consultant neuroradiologists (Group III). The mean time of acquisition of CTA and CTP studies was calculated among ten patients presenting with acute stroke. All readers had to process the CTA and CTP images, interpret them (for presence or absence of thrombus and penumbra) and save them on the GE Advantage Windows workstation. The mean time for processing and interpreting these studies was calculated. The mean time for acquisition of CTA and CTP studies in the ten patients was 14.6 +/- 5.9 minutes. The time taken for CTA processing and interpretation in Groups I, II and III was 2.3 +/- 1.3 min, 1.6 +/- 0.4 min and 1.5 +/- 0.7 min respectively. The time required for CTP processing and interpretation by the same groups was 5.2 +/- 1.7 min, 4.5 +/- 1.5 min and 4.1 +/- 1.1 min respectively. There was a statistically significant difference of means between Groups I and III in the CTA and CTP processing and interpretation times (p=0.02, p=0.01 respectively) but no statistical difference between Groups I and II (p=0.15, p=0.22 respectively) or Groups II and III (p=0.31, p=0.30 respectively). The CTA and CTP studies can be performed, processed and interpreted quickly in acute stroke.

Neuropathology and Neuroradiology a Review

The authors provide a brief and incomplete review of neuropathology and neuroradiology. The book is divided into 32 chapters: General Neuropathology, Glial Cell Response to Injury, Nervous System Development, Developmental Pathology, Perinatal Brain Injuries, Infectious Diseases, Infectious Pathogens, Oncology, Differential Diagnosis by Location, Phakomatoses, Intoxication and Drugs, Chemotherapy, Metal Toxicities, Vitamin Deficiencies, Acquired Metabolic Diseases, Congenital Metabolic Diseases, Degenerative Diseases, Demyelinating Diseases, Ischemia and Hypoxia, Vascular Diseases, CNS Trauma, Skull Diseases, Developmental Spinal Lesions, Spinal Tumors, Spinal Vascular Diseases, Spinal Infections, Spinal Inflammatory Diseases, Spinal Degenerative Diseases, Spinal Trauma, Peripheral Nerve Disorders, Neuromuscular Junction Diseases, and Muscle Diseases. The organization and presentation of the book involves the integration of the pathologic features and imaging, which is a positive feature of the text. Although separate neuropathology chapters are included, no such chapters exist for neuroradiology. This is a weakness of the book becuase it is supposed to be a review of neuroradiology and should, therefore, include a separate chapter that reviews the current status of neuroimaging techniques and the techniques that are useful in various clinical scenarios. The book is written with a bullet style in which a few important clinical and pathologic features of each entity are cited. It reads as a dictionary would, with lists of diseases and a few important clinical and pathologic features mentioned. Salient radiologic features are generally not discussed. The content of the book reflects the fact that none of the coauthors is a neuroradiologist or radiologist. Although the very basics of neuroradiology are occasionally discussed in certain diseases, recent technological advances in routine clinical use are not covered. For example, in the section dealing with cerebrovascular accidents, there is no mention of the usefulness of diffusion-weighted MR imaging. Likewise, the use of MR angiography in the evaluation of patients with atherosclerosis is not mentioned. There is a paucity of images, and the figure legends are not descriptive enough. The figure legends also contain numerous mistakes. For example, an axial fluid-attenuated inversion recovery (FLAIR) image of the brain is referred to as an “infused T1-weighted MR.” The quality of the images is adequate. The authors use nine texts as references for the entire book. These references are not directly cited in the text, and only two are radiology texts. The content appears to be fairly accurate. I am not aware of a similar book that reviews both neuropathology and neuroradiology. As far as it being a review of neuroradiology, this book is far from comprehensive, and it is not nearly as valuable the review text by Grossman and Yousem, Neuroradiology: The Requisites. Radiology residents, neuroradiology fellows, and, practicing radiologists are much better served by Grossman and Yousem’s text. The teaching value of the present book is limited to individuals who already have a substantial knowledge of the neurosciences and who are in need of a quick, brief review; however, no topic is covered to any great extent. Although this book is not comprehensive, it does provide material that medical students can use in their preparation for board examinations. The book can also be useful to pathologists, neurologists, and neurosurgeons who need a quick review before their board examinations. This book, however, is not well suited for a radiologist or neuroradiologist. Book Reviews

Book review

Book review

American Society of Neuroradiology Research Survey 2001

Rationale and Objectives Research is a critical component of the mission of academic radiology, and success in research is necessary for the future of neuroradiology. Thus, the authors set out to establish a baseline of research activities of American Society of Neuroradiology (ASNR) members. Materials and Methods The authors surveyed 100 fellowship program directors. The survey was Web based, with recruitment from the ASNR Fellowship Database survey site and with e-mail and fax solicitations to the Web site. Questions focused on neuroradiologist and neuroradiology fellow involvement in research. Results Forty-eight of the 100 program directors (48%) responded. Several key findings emerged: (a) About one-third of fellowship programs require all fellows to do some research, with most fellows receiving less than 1 day per week of academic time; (b) just over half of the programs expect fellows to publish a paper; (c) about two-thirds of academic neuroradiologists get at least 1 academic day per week; (d) most academic neuroradiologists perform research, but most of this research is unfunded; and (e) about nine of 10 academic sections have at least one neuroradiologist with some extramural funding. Conclusion The relative lack of extramural funding among academic neuroradiologists is a reality that is probably multifactorial; however, there may be a direct relationship between amount of academic time free from clinical duties and successful competition for funding. The time (and, thus, financial) support of research-oriented fellows and faculty should be increased.

The 1st year after residency: Personal reflections of a neuroradiology fellow

The 1st year after residency: Personal reflections of a neuroradiology fellow