BRAF-MEK Inhibition in Newly Diagnosed Papillary Craniopharyngiomas.

BACKGROUND: Craniopharyngiomas, primary brain tumors of the pituitary-hypothalamic axis, can cause clinically significant sequelae. Treatment with the use of surgery, radiation, or both is often associated with substantial morbidity related to vision loss, neuroendocrine dysfunction, and memory loss. Genotyping has shown that more than 90% of papillary craniopharyngiomas carry BRAF V600E mutations, but data are lacking with regard to the safety and efficacy of BRAF-MEK inhibition in patients with papillary craniopharyngiomas who have not undergone previous radiation therapy. METHODS: Eligible patients who had papillary craniopharyngiomas that tested positive for BRAF mutations, had not undergone radiation therapy previously, and had measurable disease received the BRAF-MEK inhibitor combination vemurafenib-cobimetinib in 28-day cycles. The primary end point of this single-group, phase 2 study was objective response at 4 months as determined with the use of centrally determined volumetric data. RESULTS: Of the 16 patients in the study, 15 (94%; 95% confidence interval [CI], 70 to 100) had a durable objective partial response or better to therapy. The median reduction in the volume of the tumor was 91% (range, 68 to 99). The median follow-up was 22 months (95% CI, 19 to 30) and the median number of treatment cycles was 8. Progression-free survival was 87% (95% CI, 57 to 98) at 12 months and 58% (95% CI, 10 to 89) at 24 months. Three patients had disease progression during follow-up after therapy had been discontinued; none have died. The sole patient who did not have a response stopped treatment after 8 days owing to toxic effects. Grade 3 adverse events that were at least possibly related to treatment occurred in 12 patients, including rash in 6 patients. In 2 patients, grade 4 adverse events (hyperglycemia in 1 patient and increased creatine kinase levels in 1 patient) were reported; 3 patients discontinued treatment owing to adverse events. CONCLUSIONS: In this small, single-group study involving patients with papillary craniopharyngiomas, 15 of 16 patients had a partial response or better to the BRAF-MEK inhibitor combination vemurafenib-cobimetinib. (Funded by the National Cancer Institute and others; ClinicalTrials.gov number, NCT03224767.).

Advanced Imaging in the Diagnosis and Response Assessment of High-Grade Glioma: AJR Expert Panel Narrative Review.

This AJR Expert Panel Narrative explores the current status of advanced MRI and PET techniques for the post-therapeutic response assessment of high-grade adult-type gliomas, focusing on ongoing clinical controversies in current practice. Discussed techniques that complement conventional MRI and aid the differentiation of recurrent tumor from post-treatment effects include DWI and diffusion tensor imaging; perfusion MRI techniques including dynamic susceptibility contrast (DSC), dynamic contrast-enhanced MRI, and arterial spin labeling; MR spectroscopy including assessment of 2-hydroxyglutarate (2HG) concentration; glucose- and amino acid (AA)-based PET; and amide proton transfer imaging. Updated criteria for Response Assessment in Neuro-Oncology are presented. Given the abundant supporting clinical evidence, the panel supports a recommendation that routine response assessment after HGG treatment should include perfusion MRI, particularly given the development of a consensus recommended DSC-MRI protocol. Although published studies support 2HG MRS and AA PET, these techniques' widespread adoption will likely require increased availability (for 2HG MRS) or increased insurance funding in the United States (for AA PET). The article concludes with a series of consensus opinions from the author panel, centered on the clinical integration of the advanced imaging techniques into posttreatment surveillance protocols.

A Radiologist's Guide to the 2021 WHO Central Nervous System Tumor Classification: Part 2-Newly Described and Revised Tumor Types.

The fifth edition of the World Health Organization classification of tumors of the central nervous system (CNS), published in 2021, introduces major shifts in the classification of brain and spine tumors. These changes were necessitated by rapidly increasing knowledge of CNS tumor biology and therapies, much of which is based on molecular methods in tumor diagnosis. The growing complexity of CNS tumor genetics has required reorganization of tumor groups and acknowledgment of new tumor entities. For radiologists interpreting neuroimaging studies, proficiency with these updates is critical in providing excellent patient care. This review will focus on new or revised CNS tumor types and subtypes, beyond infiltrating glioma (described in part 1 of this series), with an emphasis on imaging features.

Preliminary Experience with a Four-Lead Implantable Pulse Generator for Deep Brain Stimulation.

BACKGROUND: Implantable pulse generators (IPGs) store energy and deliver electrical impulses for deep brain stimulation (DBS) to treat neurological and psychiatric disorders. IPGs have evolved over time to meet the demands of expanding clinical indications and more nuanced therapeutic approaches. OBJECTIVES: The aim of this study was to examine the workflow of the first 4-lead IPG for DBS in patients with complex disease. METHOD: The engineering capabilities, clinical use cases, and surgical technique are described in a cohort of 12 patients with epilepsy, essential tremor, Parkinson's disease, mixed tremor, and Tourette's syndrome with comorbid obsessive-compulsive disorder between July 2021 and July 2022. RESULTS: This system is a rechargeable 32-channel, 4-port system with independent current control that can be connected to 8 contact linear or directionally segmented leads. The system is ideal for patients with mixed disease or those with multiple severe symptoms amenable to >2 lead implantations. A multidisciplinary team including neurologists, radiologists, and neurosurgeons is necessary to safely plan the procedure. There were no serious intraoperative or postoperative adverse events. One patient required revision surgery for bowstringing. CONCLUSIONS: This new 4-lead IPG represents an important new tool for DBS surgery with the ability to expand lead implantation paradigms for patients with complex disease.

A Radiologist's Guide to the 2021 WHO Central Nervous System Tumor Classification: Part I-Key Concepts and the Spectrum of Diffuse Gliomas.

The fifth edition of the World Health Organization (WHO) classification of tumors of the central nervous system, published in 2021, contains substantial updates in the classification of tumor types. Many of these changes are relevant to radiologists, including "big picture" changes to tumor diagnosis methods, nomenclature, and grading, which apply broadly to many or all central nervous system tumor types, as well as the addition, elimination, and renaming of multiple specific tumor types. Radiologists are integral in interpreting brain tumor imaging studies and have a considerable impact on patient care. Thus, radiologists must be aware of pertinent changes in the field. Staying updated with the most current guidelines allows radiologists to be informed and effective at multidisciplinary tumor boards and in interactions with colleagues in neuro-oncology, neurosurgery, radiation oncology, and neuropathology. This review represents the first of a two-installment review series on the most recent changes to the WHO brain tumor classification system. This first installment focuses on the changes to the classification of adult and pediatric gliomas of greatest relevance for radiologists.

Onset of progressive motor impairment in patients with critical central nervous system demyelinating lesions.

OBJECTIVE: To compare progressive motor impairment onset attributable to a "critical" central nervous system (CNS) demyelinating lesion in patients with highly restricted versus unlimited magnetic resonance imaging (MRI) lesion burden. METHODS: We identified 135 patients with progressive motor impairment for ⩾1 year attributable to a "critical" demyelinating lesion with: MRI burden of 1 lesion ("progressive solitary sclerosis"), 2-5 lesions ("progressive paucisclerosis"), or unrestricted (>5) lesions and "progressive unilateral hemiparesis." Neuroradiology review of brain and spinal cord MRI documented unequivocally demyelinating lesions. RESULTS: A total of 33 (24.4%) patients had progressive solitary sclerosis; 56 (41.5%) patients had progressive paucisclerosis; and 46 (34.1%) patients had progressive unilateral hemiparesis. Median age at onset of progressive motor impairment was younger in progressive solitary sclerosis (49 years; range 24-73) and progressive paucisclerosis (50 years; range 30-64) than in progressive unilateral hemiparesis (54 years; range 39-77; p = 0.02 and p = 0.003, respectively). Within progressive unilateral hemiparesis, motor-progression onset was similar between those with 4-10, 11-20, or >20 brain lesions (55, 54, 53 years of age, respectively; p = 0.44). CONCLUSION: Motor-progression age is similar, but paradoxically earlier, in cohorts with highly restricted CNS lesion burden than in those with unrestricted lesion burden with progressive unilateral hemiparetic MS. The "critical" demyelinating lesion rather than total brain MRI lesion burden is the major contributor to motor-progression onset in these cohorts.

Advanced MRI techniques for transcranial high intensity focused ultrasound targeting.

Magnetic resonance guided high intensity focused ultrasound is a novel, non-invasive, image-guided procedure that is able to ablate intracranial tissue with submillimetre precision. It is currently FDA approved for essential tremor and tremor dominant Parkinson's disease. The aim of this update is to review the limitations of current landmark-based targeting techniques of the ventral intermediate nucleus and demonstrate the role of emerging imaging techniques that are relevant for both magnetic resonance guided high intensity focused ultrasound and deep brain stimulation. A significant limitation of standard MRI sequences is that the ventral intermediate nucleus, dentatorubrothalamic tract, and other deep brain nuclei cannot be clearly identified. This paper provides original, annotated images demarcating the ventral intermediate nucleus, dentatorubrothalamic tract, and other deep brain nuclei on advanced MRI sequences such as fast grey matter acquisition T1 inversion recovery, quantitative susceptibility mapping, susceptibility weighted imaging, and diffusion tensor imaging tractography. Additionally, the paper reviews clinical efficacy of targeting with these novel MRI techniques when compared to current established landmark-based targeting techniques. The paper has widespread applicability to both deep brain stimulation and magnetic resonance guided high intensity focused ultrasound.

Cerebrospinal fluid drainage complications during first stage and completion fenestrated-branched endovascular aortic repair.

OBJECTIVE: To determine the rates and risk factors of complications related to cerebrospinal fluid drainage (CSFD) during first stage and completion fenestrated-branched endovascular aortic repair (F-BEVAR) of pararenal and thoracoabdominal aortic aneurysms. METHODS: We reviewed the outcomes of 293 consecutive patients enrolled in a prospective, nonrandomized study to investigate outcomes of F-BEVAR between 2013 and 2018. Patients who received CSFD during first-stage thoracic endovascular aortic repair, index F-BEVAR, or completion of temporary aneurysm sac perfusion procedures were included in the analysis. CSFD complications were graded as severe or moderate if they were life threatening, escalated the level of care, or prolonged the hospital stay. Presence of substantial degenerative lumbar disease (DLD) was identified based on review of preoperative computed tomography. End points included technical difficulties during CSFD placement and CSFD-related complications. RESULTS: A total of 187 patients (mean age, 73 ± 8 years; 70% male) treated for 20 pararenal and 167 thoracoabdominal aortic aneurysms received CSFD in 240 procedures, including 51 first-stage thoracic endovascular aortic repairs, 184 index F-BEVARs, and 5 completion temporary aneurysm sac perfusion procedures. Nineteen patients (10%) had 22 CSFD-related complications after 21 aortic procedures (9%). Complications were graded as severe to moderate in 17 patients (9%). There were 12 patients (6%) with intracranial hypotension, including three (2%) who had intracranial hemorrhage and nine (5%) with post dural puncture headache requiring blood patches in six. Another six patients (3%) developed spinal hematomas resulting in paraplegia in two (1%) and transient paraparesis in two (1%). One patient had CSF leakage from the puncture site (no intervention required). Four patients had bleeding during attempted drain placement, which required postponement of F-BEVAR. Technical difficulties were experienced in 57 drain insertions (24%), more often in patients with DLD than in those without DLD (35/113 [31%] vs 22/121 [18%]; P = .03). Fluoroscopic guidance was used in 44 drain placements (18%) with a lower rate of technical difficulties compared with the blind approach (9% vs 28%; P = .01). There was a statistically nonsignificant trend toward more complications in patients with technical challenges (14% vs 7%; P = .10). Of 13 study patients who developed spinal cord injuries during aortic procedures, 4 (31%) were attributed to CSFD. CONCLUSIONS: Although CSFD is widely used to prevent ischemic spinal cord injury during complex aortic repair, the risk of major CSFD-related complications is not negligible and should be carefully weighed against its potential benefits. One-third of spinal cord injuries were caused by CSF drain placement. The use of fluoroscopic guidance may decrease the risk of CSFD-related complications.

Synovial Cysts Confounding Access to the Dorsal S1 Neural Foramen in Transforaminal Epidural Steroid Injections.

OBJECTIVES: The S1 dorsal foramen is the route for 30% of lumbar transforaminal epidural injections; it is therefore important to identify structures impeding S1 foraminal access. The study objective was to characterize the imaging findings, prevalence, and anatomic origin of synovial cysts presenting within the S1 neural foramen. METHODS: A case series (N = 14) established imaging characteristics of S1 synovial cysts. Imaging studies of 400 patients undergoing epidural injections were reviewed for lesions compromising S1 foraminal access. Cadaveric dissections defined the relationship of the inferior recess of the L5-S1 facet to the S1 dorsal foramen. RESULTS: Elderly patients (mean age = 76) exhibited S1 synovial cysts. Synovial cysts were typically 1-2 cm in diameter, hyperintense on sagittal T2 weighted magnetic resonance images (MRIs), fluid-density on computed tomography, and dorsal to the S1 spinal nerve. Sixty percent of cysts exhibited complex MRI signal characteristics (thick wall, internal structure). Tarlov cysts, in contrast, were larger, lobular, and exhibited pure fluid intensity. Lesions impeded access to the S1 dorsal foramina in 5% of reviewed imaging studies (16 Tarlov cysts, three synovial cysts, one conjoint S1-S2 nerve root). The multifidus muscle was interposed between the L5-S1 facet inferior recess and the S1 dorsal foramen on dissection specimens; severe atrophy of the ipsilateral multifidus was noted on imaging in 17/18 synovial cysts. CONCLUSIONS: The S1 neural foramina should be inspected on sagittal MRI, when available, for confounding lesions before performing S1 epidural injections. Tarlov cysts are more common than synovial cysts; the latter are seen in elderly patients with severe multifidus atrophy.

Does pituitary compression/empty sella syndrome contribute to MRI-negative Cushing's disease? A single-institution experience.

OBJECTIVE: Cushing's disease arises from functioning adrenocorticotropic hormone (ACTH)-secreting pituitary adenomas. These tumors can be very small and evade detection by MRI. Empty sella syndrome is a phenomenon by which an arachnoid outpouching of CSF into the sella leads to compression of the pituitary, likely due to intracranial hypertension (a common issue in Cushing's disease), further leading to difficulty in visualizing the pituitary gland that may contribute to difficulty in finding a tumor on MRI, so-called MRI-negative Cushing's disease. The authors sought to examine the association between empty sella syndrome and MRI-negative Cushing's disease. METHODS: A single-institution database of Cushing's disease cases from 2000 to 2017 was reviewed, and 197 cases were included in the analysis. One hundred eighty patients had a tissue diagnosis of Cushing's disease and 17 had remission with surgery, but no definitive tissue diagnosis was obtained. Macroadenomas (tumors > 1 cm) were excluded. The degree of empty sella syndrome was graded on the degree of CSF visualized in the sella on midline sagittal T1-weighted MRI. RESULTS: Of the 197 cases identified, 40 (20%) presented with MRI-negative disease, and empty sella syndrome was present in 49 cases (25%). MRI-negative disease was found in 18 (37%) of 49 empty sella cases versus 22 (15%) of 148 cases without empty sella syndrome present. Empty sella syndrome was significantly associated with MRI-negative disease (OR 3.32, 95% CI 1.61-6.74, p = 0.0018). Decreased thickness of the pituitary gland was also associated with MRI-negative disease (mean thickness 5.6 vs 6.8 mm, p = 0.0002). CONCLUSIONS: Empty sella syndrome is associated with an increased rate of MRI-negative Cushing's disease. Pituitary compression causing a relative reduction in the volume of the pituitary for imaging is a plausible cause for not detecting the tumor mass with MRI.

MRI and tractography techniques to localize the ventral intermediate nucleus and dentatorubrothalamic tract for deep brain stimulation and MR-guided focused ultrasound: a narrative review and update.

The thalamic ventral intermediate nucleus (VIM) can be targeted for treatment of tremor by several procedures, including deep brain stimulation (DBS) and, more recently, MR-guided focused ultrasound (MRgFUS). To date, such targeting has relied predominantly on coordinate-based or atlas-based techniques rather than directly targeting the VIM based on imaging features. While general regional differences of features within the thalamus and some related white matter tracts can be distinguished with conventional imaging techniques, internal nuclei such as the VIM are not discretely visualized. Advanced imaging methods such as quantitative susceptibility mapping (QSM) and fast gray matter acquisition T1 inversion recovery (FGATIR) MRI and high-field MRI pulse sequences that improve the ability to image the VIM region are emerging but have not yet been shown to have reliability and accuracy to serve as the primary method of VIM targeting. Currently, the most promising imaging approach to directly identify the VIM region for clinical purposes is MR diffusion tractography.In this review and update, the capabilities and limitations of conventional and emerging advanced methods for evaluation of internal thalamic anatomy are briefly reviewed. The basic principles of tractography most relevant to VIM targeting are provided for familiarization. Next, the key literature to date addressing applications of DTI and tractography for DBS and MRgFUS is summarized, emphasizing use of direct targeting. This literature includes 1-tract (dentatorubrothalamic tract [DRT]), 2-tract (pyramidal and somatosensory), and 3-tract (DRT, pyramidal, and somatosensory) approaches to VIM region localization through tractography.The authors introduce a 3-tract technique used at their institution, illustrating the oblique curved course of the DRT within the inferior thalamus as well as the orientation and relationship of the white matter tracts in the axial plane. The utility of this 3-tract tractography approach to facilitate VIM localization is illustrated with case examples of variable VIM location, targeting superior to the anterior commissure-posterior commissure plane, and treatment in the setting of pathologic derangement of thalamic anatomy. Finally, concepts demonstrated with these case examples and from the prior literature are synthesized to highlight several potential advantages of tractography for VIM region targeting.

A phase 1 and randomized, placebo-controlled phase 2 trial of bevacizumab plus dasatinib in patients with recurrent glioblastoma: Alliance/North Central Cancer Treatment Group N0872.

BACKGROUND: Src signaling is markedly upregulated in patients with invasive glioblastoma (GBM) after the administration of bevacizumab. The Src family kinase inhibitor dasatinib has been found to effectively block bevacizumab-induced glioma invasion in preclinical models, which led to the hypothesis that combining bevacizumab with dasatinib could increase bevacizumab efficacy in patients with recurrent GBM. METHODS: After the completion of the phase 1 component, the phase 2 trial (ClinicalTrials.gov identifier NCT00892177) randomized patients with recurrent GBM 2:1 to receive 100 mg of oral dasatinib twice daily (arm A) or placebo (arm B) on days 1 to 14 of each 14-day cycle combined with 10 mg/kg of intravenous bevacizumab on day 1 of each 14-day cycle. The primary endpoint was 6-month progression-free survival (PFS6). RESULTS: In the 121 evaluable patients, the PFS6 rate was numerically, but not statistically, higher in arm A versus arm B (28.9% [95% CI, 19.5%-40.0%] vs 18.4% [95% CI, 7.7%-34.4%]; P = .22). Similarly, there was no significant difference in the median overall survival noted between the treatment arms (7.3 months and 7.7 months, respectively; P = .93). The objective response rate was 15.7% in arm A and 26.3% in arm B (P = .52), but with a significantly longer duration in patients treated on arm A (16.3 months vs 2 months). The incidence of grade ≥3 toxicity was comparable between treatment arms, with hematologic toxicities occurring more frequently in arm A versus arm B (15.7% vs 7.9%) (adverse events were assessed as per the National Cancer Institute Common Terminology Criteria for Adverse Events [version 4.0]). Correlative tissue analysis demonstrated an association between pSRC/LYN signaling in patient tumors and outcome. CONCLUSIONS: Despite upregulation of Src signaling in patients with GBM, the combination of bevacizumab with dasatinib did not appear to significantly improve the outcomes of patients with recurrent GBM compared with bevacizumab alone.

Demographics and clinical characteristics of episodic hypothermia in multiple sclerosis.

BACKGROUND: Episodic hypothermia (EH) can occur in multiple sclerosis (MS). The putative mechanism is impairment of thermoregulation due to a presumed demyelinating hypothalamic lesion. OBJECTIVE: To describe a cohort of patients with MS, who developed EH. METHODS: Patients were identified through review of the Mayo Clinic electronic medical record (1996 to July 2015). Search terms were [multiple sclerosis] or [MS] within the diagnoses field and [hypothermia] within any field. We reviewed records for accuracy of diagnoses and abstracted relevant data. Magnetic resonance imaging (MRI) was reviewed for presence of hypothalamic lesions. RESULTS: Of 156 patients, 34 had concurrent MS and hypothermia. Thirty-two (94%) had progressive disease at EH onset. Median MS duration was 19.9 years, and median expanded disability status scale (EDSS) was 8.0. Most patients presented with alterations in consciousness. Infection was suspected as the precipitating factor in 19 (56%), but clinically/laboratory supported in only 9 (28%). MRI lesions were evident within the hypothalamus in only 4 (14%). CONCLUSION: EH occurs predominantly in patients with advanced secondary progressive MS. The major manifestation is altered consciousness. Infection is often suspected as causal, but infrequently confirmed. Although commonly implicated, hypothalamic lesions were rarely evident on MRI and were absent in two post-mortem evaluations.

Plenty of calcification: imaging characterization of polymorphous low-grade neuroepithelial tumor of the young.

PURPOSE: Polymorphous low-grade neuroepithelial tumor of the young (PLNTY) is a recently described epileptogenic neoplasm. As the name implies, PLNTYs are indolent tumors most often encountered in the pediatric or young adult population. The imaging features of PLNTY are not well characterized in the existing literature. METHODS: We performed a retrospective review, identifying nine patients with pathologically proven PLNTY and available preoperative imaging in order to identify common features which may facilitate confident imaging diagnosis of this entity. RESULTS: Patients were ages 5 to 34 years (median 16 years), and seven (78%) were female. Most tumors had a highly characteristic appearance, with temporal lobe location (6/9; 67%), calcification (8/9; 89%), cortical/subcortical origin (8/9; 89%), cystic components (8/9; 89%), and relatively infrequent contrast enhancement (3/9; 33%). CONCLUSION: PLNTYs demonstrate characteristic calcification, subcortical location, and frequent temporal lobe localization, features that may allow radiologists to prospectively suggest the diagnosis in the proper clinical setting.

There is an exception to every rule-T2-FLAIR mismatch sign in gliomas.

The T2-FLAIR mismatch sign, in which a low-grade glioma is hyperintense on T2-weighted MR and centrally hypointense on T2-weighted FLAIR MR, has been reported as 100% specific for IDH-mutant astrocytomas in several series. We report several cases of "false positive" T2-FLAIR mismatch sign occurring outside the context of IDH-mutant astrocytomas, predominantly in children or young adults with pediatric-type gliomas. These results suggest caution in the interpretation of the T2-FLAIR mismatch sign in the pediatric glioma population.

Progressive motor impairment from a critically located lesion in highly restricted CNS-demyelinating disease.

OBJECTIVE: To report progressive motor impairment from a critically located central nervous system (CNS) demyelinating lesion in patients with restricted magnetic resonance imaging (MRI)-lesion burden. METHODS: We identified 38 patients with progressive upper motor-neuron impairment for >1 year, 2-5 MRI CNS-demyelinating lesions, with one seemingly anatomically responsible for progressive motor impairment. Patients with any alternative etiology for progressive motor impairment were excluded. A neuroradiologist blinded to clinical evaluation reviewed multiple brain and spinal-cord MRI, selecting a candidate critically located demyelinating lesion. Lesion characteristics were determined and subsequently compared with clinical course. RESULTS: Median onset age was 47.5 years (24-64); 23 (61%) women. Median follow-up was 94 months (18-442); median Expanded Disability Status Scale Score (EDSS) at last follow-up was 4.5 (2-10). Clinical presentations were progressive: hemiparesis/monoparesis 31; quadriparesis 5; and paraparesis 2; 27 patients had progression from onset; 11 progression post-relapse. Total MRI lesions were 2 ( n = 8), 3 ( n = 12), 4 ( n = 12), and 5 ( n = 6). Critical lesions were located on corticospinal tracts, chronically atrophic in 26/38 (68%) and involved cervical spinal cord in 27, cervicomedullary/brainstem region in 6, thoracic spinal cord in 4, and subcortical white matter in 1. CONCLUSION: Progressive motor impairment may ascribe to a critically located CNS-demyelinating lesion in patients with highly restricted MRI burden. Motor progression from a specific demyelinating lesion has implications for understanding multiple sclerosis (MS) progression.

Fast gray matter acquisition T1 inversion recovery MRI to delineate the mammillothalamic tract for preoperative direct targeting of the anterior nucleus of the thalamus for deep brain stimulation in epilepsy.

When medically intractable epilepsy is multifocal or focal but poorly localized, neuromodulation can be useful therapy. One such technique is deep brain stimulation (DBS) targeting the anterior nucleus of the thalamus (ANT). Unfortunately, the ANT is difficult to visualize in standard MRI sequences and its indirect targeting is difficult because of thalamic variability and atrophy in patients with epilepsy. The following study describes the novel use of the fast gray matter acquisition T1 inversion recovery (FGATIR) MRI sequence to delineate the mammillothalamic tract for direct targeting of the ANT through visualizing the termination of the mammillothalamic tract in the ANT. The day prior to surgery in a 19-year-old, right-handed woman with a 5-year history of epilepsy, MRI was performed on a 3-T Siemens Prisma scanner (Siemens AG, Healthcare Sector) using a 64-channel head and neck coil. As part of the imaging protocol, noncontrast magnetization-prepared rapid gradient echo (MP-RAGE) and diffusion tensor imaging (DTI) sequences were obtained for targeting purposes. The ANT was directly targeted using the FGATIR sequence, and bilateral Medtronic 3389 leads were placed. At the last follow-up (2 months), the patient reported an approximate 75% decrease in seizure frequency, as well as a decrease in seizure severity.

Discriminating long myelitis of neuromyelitis optica from sarcoidosis.

OBJECTIVE: To compare longitudinally extensive myelitis in neuromyelitis optica spectrum disorders (NMOSD) and spinal cord sarcoidosis (SCS). METHODS: We identified adult patients evaluated between 1996 and 2015 with SCS or NMOSD whose first myelitis episode was accompanied by a spinal cord lesion spanning ≥3 vertebral segments. All NMOSD patients were positive for aquaporin-4-immunoglobulin G, and all sarcoidosis cases were pathologically confirmed. Clinical characteristics were evaluated. Spine magnetic resonance imaging was reviewed by 2 neuroradiologists. RESULTS: We studied 71 patients (NMOSD, 37; SCS, 34). Sixteen (47%) SCS cases were initially diagnosed as NMOSD or idiopathic transverse myelitis. Median delay to diagnosis was longer for SCS than NMOSD (5 vs 1.5 months, p < 0.01). NMOSD myelitis patients were more commonly women, had concurrent or prior optic neuritis or intractable vomiting episodes more frequently, had shorter time to maximum deficit, and had systemic autoimmunity more often than SCS (p < 0.05). SCS patients had constitutional symptoms, cerebrospinal fluid (CSF) pleocytosis, and hilar adenopathy more frequently than NMOSD (p < 0.05); CSF hypoglycorrhachia (11%, p = 0.25) and elevated angiotensin-converting enzyme (18%, p = 0.30) were exclusive to SCS. Dorsal cord subpial gadolinium enhancement extending ≥2 vertebral segments and persistent enhancement >2 months favored SCS, and ringlike enhancement favored NMOSD (p < 0.05). Maximum disability was similar in both disorders. INTERPRETATION: SCS is an under-recognized cause of longitudinally extensive myelitis that commonly mimics NMOSD. We identified clinical, laboratory, systemic, and radiologic features that, taken together, help discriminate SCS from NMOSD.

Ring-enhancing spinal cord lesions in neuromyelitis optica spectrum disorders.

OBJECTIVE: We assessed the frequency and characteristics of ring-enhancing spinal cord lesions in neuromyelitis optica spectrum disorder (NMOSD) myelitis and myelitis of other cause. METHODS: We reviewed spinal cord MRIs for ring-enhancing lesions from 284 aquaporin-4 (AQP4)-IgG seropositive patients at Mayo Clinic from 1996 to 2014. Inclusion criteria were as follows: (1) AQP4-IgG seropositivity, (2) myelitis attack and (3) MRI spinal cord demonstrating ring-enhancement. We identified two groups of control patients with: (1) longitudinally extensive myelopathy of other cause (n=66) and (2) myelitis in the context of a concurrent or subsequent diagnosis of multiple sclerosis (MS) from a population-based cohort (n=30). RESULTS: Ring-enhancement was detected in 50 of 156 (32%) myelitis episodes in 41 patients (83% single; 17% multiple attacks). Ring-enhancement was noted on sagittal and axial images in 36 of 43 (84%) ring enhancing myelitis episodes and extended a median of two vertebral segments (range, 1-12); in 21 of 48 (44%) ring enhancing myelitis episodes, the ring extended greater than or equal to three vertebrae. Ring-enhancement was accompanied by longitudinally extensive (greater than or equal to three vertebral segments) T2-hyperintensity in 44 of 50 (88%) ring enhancing myelitis episodes. One case of a spinal cord biopsy during ring-enhancing myelitis revealed tissue vacuolation and loss of AQP4 immunoreactivity with preserved axons. The clinical characteristics of ring-enhancing myelitis episodes did not differ from non-ring-enhancing episodes. Ring-enhancing spinal cord lesions were more common in NMOSD than other causes of longitudinally extensive myelopathy (50/156 (32%) vs 0/66 (0%); p≤0.001) but did not differ between NMOSD and MS (50/156 (32%) vs 6/30 (20%); p=0.20). CONCLUSIONS: Spinal cord ring-enhancement accompanies one-third of NMOSD myelitis episodes and distinguishes NMOSD from other causes of longitudinally extensive myelopathies but not from MS.