Amy L. Kotsenas

Basal ganglia T1 hyperintensity in LGI1-autoantibody faciobrachial dystonic seizures.

Objective: To characterize the clinical features and MRI abnormalities of leucine-rich glioma-inactivated 1 (LGI1)-autoantibody (Ab) faciobrachial dystonic seizures (FBDS). Methods: Forty-eight patients with LGI1-Ab encephalopathy were retrospectively identified by searching our clinical and serologic database from January 1, 2002, to June 1, 2015. Of these, 26 met inclusion criteria for this case series: LGI1-Ab seropositivity and FBDS. In a separate analysis of all 48 patients initially identified, the MRIs of patients with (n = 26) and without (n = 22) FBDS were compared by 2 neuroradiologists blinded to the clinical details. Results: The median age of the 26 included patients was 62.5 years (range 37–78); 65% were men. FBDS involved arm (26), face (22), and leg (12). Ten were previously diagnosed as psychogenic. Ictal EEGs were normal in 20 of 23 assessed. Basal ganglia T1 and T2 signal abnormalities were detected in 11 patients (42%), with excellent agreement between neuroradiologists (κ scores of 0.86 and 0.93, respectively), and included T1 hyperintensity alone (2), T2 hyperintensity alone (1), or both (8). The T1 hyperintensities persisted longer than the T2 hyperintensities (median 11 weeks vs 1 week, p = 0.02). Improvement with immunotherapy (18/18) was more frequent than with antiepileptic medications (10/24). A separate analysis of all 48 patients initially identified with LGI1-Ab encephalopathy showed that basal ganglia MRI abnormalities were present in 11 of 26 with FBDS but not present in those without FBDS (0/22) (p < 0.001). In contrast, mesial temporal MRI abnormalities were less common among those with FBDS (42%) than those without (91%) (p < 0.001). Conclusions: Basal ganglia T1 hyperintensity is a clinically useful MRI biomarker of LGI1-Ab FBDS and suggests a basal ganglia localization.

The Role of Digital Subtraction Myelography in the Diagnosis and Localization of Spontaneous Spinal CSF Leaks

OBJECTIVE The objective of our study was to review the clinical utility of digital subtraction myelography for the diagnosis of spinal CSF leaks in patients with spontaneous intracranial hypotension (SIH) and those with superficial siderosis. MATERIALS AND METHODS Procedure logs from 2007 to 2011 were reviewed to identify cases in which digital subtraction myelography was performed to diagnose spinal CSF leaks. Electronic medical records were reviewed to obtain information regarding diagnosis and outcome. For patients to be included in the study, preprocedural spinal MRI had to show an extradural fluid collection spanning more than one vertebral level and postmyelographic CT had to confirm the presence of an active CSF leak. If digital subtraction myelography successfully showed the site of the CSF leak, the location was documented. RESULTS Eleven patients (seven men and four women; mean age, 49.0 years) underwent digital subtraction myelography during the study period. Six patients had SIH and five patients had superficial siderosis. The extradural fluid collection on spinal MRI averaged a length of 15.5 vertebral levels. Digital subtraction myelography successfully showed the site of the CSF leak in nine of the 11 patients, and all of the dural tears were located in the thoracic spine between T3 and T11. CONCLUSION Digital subtraction myelography is a valuable diagnostic tool for the localization of rapid spinal CSF leaks and should be considered in patients who are clinically suspected to have a dural tear that is accompanied by a longitudinally extensive extradural fluid collection on spinal MRI.

CT Metal Artifact Reduction in the Spine: Can an Iterative Reconstruction Technique Improve Visualization?

CT images were reconstructed by using weighted filtered back-projection and iterative metal artifact reduction. Two neuroradiologists evaluated images in the region of spinal hardware and assigned a score for the visualization of critical anatomic structures by using soft-tissue and bone windows. Using bone windows, they measured the length of the most pronounced linear artifacts. Visualization of critical soft-tissue anatomic structures was significantly improved by using iterative metal artifact reduction, but there was not a significant improvement in visualization of critical osseous structures. Routine generation of these iterative reconstructed images in addition to routine weighted filtered back-projection is recommended. BACKGROUND AND PURPOSE: Metal-related artifacts from spine instrumentation can obscure relevant anatomy and pathology. We evaluated the ability of CT images reconstructed with and without iterative metal artifact reduction to visualize critical anatomic structures in postoperative spines and assessed the potential for implementation into clinical practice. MATERIALS AND METHODS: We archived CT projection data in patients with instrumented spinal fusion. CT images were reconstructed by using weighted filtered back-projection and iterative metal artifact reduction. Two neuroradiologists evaluated images in the region of spinal hardware and assigned a score for the visualization of critical anatomic structures by using soft-tissue and bone windows (critical structures totally obscured, n = 0; anatomic recognition with high diagnostic confidence, n = 5). Using bone windows, we measured the length of the most pronounced linear artifacts. For each patient, neuroradiologists made recommendations regarding the optimal use of iterative metal artifact reduction and its impact on diagnostic confidence. RESULTS: Sixty-eight patients met the inclusion criteria. Visualization of critical soft-tissue anatomic structures was significantly improved by using iterative metal artifact reduction compared with weighted filtered back-projection (median, 1 ± 1.5 versus 3 ± 1.3, P < .001), with improvement in the worst visualized anatomic structure in 88% (60/68) of patients. There was not significant improvement in visualization of critical osseous structures. Linear metal artifacts were reduced from 29 to 11 mm (P < .001). In 87% of patients, neuroradiologists recommended reconstructing iterative metal artifact reduction images instead of weighted filtered back-projection images, with definite improvement in diagnostic confidence in 32% (22/68). CONCLUSIONS: Iterative metal artifact reduction improves visualization of critical soft-tissue structures in patients with spinal hardware. Routine generation of these images in addition to routine weighted filtered back-projection is recommended.

Expanded phenotypes and outcomes among 256 LGI1/CASPR2-IgG–positive patients

To describe an expanded phenotypic spectrum and longitudinal outcome in 256 LGI1‐IgG–seropositive and/or CASPR2‐IgG–seropositive patients.

Cervical Spine MR Imaging Findings of Patients with Hirayama Disease in North America: A Multisite Study

The authors sought to determine if Hirayama disease in North America has the same imaging findings as it does in Asia. They assessed imaging studies in 21 patients and looked for loss of attachment of posterior dura, lower cord atrophy and high T2 signal, loss of cervical lordosis, and anterior dural shift in flexion. These 4 findings were able to discriminate patients from healthy controls. MR imaging findings in white North American patients with Hirayama disease include loss of attachment on neutral images and forward displacement of the dura with flexion. Findings are often present on neutral MR images and, in the appropriate clinical scenario, should prompt flexion MR imaging to evaluate anterior dural shift. BACKGROUND AND PURPOSE: Most studies of HD have been conducted in Asia, particularly Japan. To characterize the MR imaging findings of North American patients with HD, we reviewed neutral and flexion cervical MR imaging examinations performed for possible HD at 3 academic medical centers located in the Southeastern, Southwestern, and Midwestern regions of the United States. MATERIALS AND METHODS: Three neuroradiologists assessed the MR imaging examinations in a blinded fashion and reached a consensus rating for LOA of the posterior dura to the spine, lower spinal cord atrophy, spinal cord T2 hyperintensity, loss of cervical lordosis, anterior dural shift with flexion, and confidence of imaging diagnosis. Final reference diagnosis was established separately with a retrospective chart review by a neurologist. RESULTS: Twenty-one patients met the criteria for HD, all were North American males and all who reported their race were white. Seventeen patients did not meet the criteria and served as controls. Four imaging attributes, LOA, dural shift with flexion, consensus diagnosis of neutral images, and consensus diagnosis of combined neutral and flexion images were all able to discriminate the group with HD from the group without HD (P < .05 for each). Findings of HD were often present on neutral images, but the addition of flexion images increased diagnostic confidence. CONCLUSIONS: MR imaging findings in white North American patients with HD include LOA on neutral images and forward displacement of the dura with flexion. Findings are often present on neutral MR images and, in the appropriate clinical scenario, should prompt flexion MR imaging to evaluate anterior dural shift.

Imaging of Posterior Element Axial Pain Generators : Facet Joints, Pedicles, Spinous Processes, Sacroiliac Joints, and Transitional Segments

The role of the posterior elements in generating axial back and neck pain is well established; the imaging detection of posterior element pain generators remains problematic. Morphologic imaging findings have proved to be nonspecific and are frequently present in asymptomatic patients. Edema, inflammation, and hypervascularity are more specific for sites of pain generation, but are often overlooked by imagers if physiologic imaging techniques such as fat-suppressed T2 or contrast-enhanced T1-weighted magnetic resonance imaging, radionuclide bone scanning with single-photon emission computed tomography (CT), or (18)F-fluorodeoxyglucose positron emission tomography combined with CT are not used.

Position-related variability of CSF opening pressure measurements.

BACKGROUND AND PURPOSE: Normative data for CSF OP have previously been established with patients in the LD position. During fluoroscopically guided LP procedures, radiologists frequently obtain these OP measurements with patients prone. In this prospective study, our goal was to determine the variability of OP measurements as a function of patient positioning and to assess whether there is a relationship with patient BMI. MATERIALS AND METHODS: Consecutive patients reporting for fluoroscopically guided LP or myelography were enrolled. OP was measured with the patient in 3 positions, with the order of the technique randomized: prone with table flat, prone with table tilted until the hub of the needle was at the level of the right atrium, and LD with the needle hub at the level of the spinal canal. The BMI of each patient was calculated. The Wilcoxon signed-rank test and linear regression analysis with bivariate fit of difference were used for analysis. RESULTS: OP measurements with the patient in the prone position were significantly elevated compared with those in the LD position, with mean differences of 2.7 (P < .001) and 1.6 cm H2O, (P = .017) for prone flat and prone tilted, respectively. There was no significant difference in OP measurements for the prone flat versus prone tilted positions (P = .20). There was no correlation between BMI and observed differences (LD-flat: R2 = 0.00028; LD-tilt: R2 = 0.00038; prone-tilt: R2 = 0.00000020). CONCLUSIONS: Measuring OP with the patient in the prone position may result in overestimation of CSF pressure. Table tilt did not significantly impact mean prone OP. Radiologists should specify exact patient positioning when reporting OP measurements.

MRI Findings in Nonlesional Hypertrophic Olivary Degeneration.

Investigate the relative frequency of nonlesional versus lesional hypertrophic olivary degeneration (HOD) and potential explanations for nonlesional HOD.

Frequency of bilateral hypertrophic olivary degeneration in a large retrospective cohort.

Hypertrophic olivary degeneration (HOD) is an uncommon type of transneuronal degeneration. Case reports and case series described in the literature provide a foundation of our current knowledge of HOD. These reports have described HOD most frequently to be unilateral and occurring in association with lesions in the dentato‐rubro‐olivary pathway. Our purpose was to evaluate the rate of bilateral versus unilateral HOD in a large case series.

Tumefactive Cerebral Amyloid Angiopathy Mimicking CNS Neoplasm

OBJECTIVE The tumefactive variant of cerebral amyloid angiopathy (CAA) is rare. In this article we describe imaging findings associated with this entity and evaluate the role of susceptibility MRI sequences in its diagnosis. CONCLUSION Our findings suggest that in elderly patients, susceptibility sequences should be part of prebiopsy MRI for tumefactive lesions. Identification of characteristic diffuse microhemorrhages should prompt inclusion of CAA in the differential diagnosis, targeted biopsy of the cortex and leptomeninges, and pathologic staining for CAA.