Leptomeningeal Enhancement on 3D-FLAIR MRI in Multiple Sclerosis: Systematic Observations in Clinical Practice.

BACKGROUND AND PURPOSE: Meningeal inflammation is implicated in cortical demyelination and disability progression in multiple sclerosis (MS). Gadolinium (Gd)-enhanced 3-dimensional (3D) FLAIR (fluid-attenuated inversion recovery) magnetic resonance imaging (MRI) can identify leptomeningeal enhancement (LME) in MS. Further characterization is needed to determine if LME is an imaging biomarker for meningeal inflammation. We sought to characterize the natural history of LME in the community setting, including persistence/resolution, effect of disease-modifying therapy, scanner variability, timing of acquisition, and imaging pitfalls that may lead to misinterpretation. METHODS: A total of 341 MRI exams with Gd-enhanced 3D-FLAIR were reviewed in MS and non-MS patients to determine frequency of enhancement by MS subtype and association with therapy. A phantom was used to assess scanner variability. Two MS patients with seven LME were imaged at four postinjection time points to generate time-intensity curves. Imaging pitfalls were compiled. RESULTS: A total of 16.6% (40/241) of MS patients revealed LME compared to 8% (8/100) in non-MS patients (P = .04). There was no association with MS subtype, therapy, or disease activity. Detection using General Electric's version of 3D-FLAIR (29%) was greater than with Siemen's 3D-FLAIR (12%) at 1.5T (Tesla) (P < .001). Lesions were generally stable but resolved in 2 patients following high-dose steroids. LME kinetics were heterogeneous, even within patients, without uniform optimal time for acquisition. Enhancement curves exhibited three different variations, similar to the two-compartment model. Imaging pitfalls included enhancements of uncertain biologic significance, cortical veins and anatomic structures, and imaging artifacts. CONCLUSIONS: Awareness of LME characteristics, variability with imaging parameters, and imaging pitfalls will facilitate determining the potential role as an imaging biomarker for meningeal inflammation.

Nontraumatic Spinal Cord Compression: MRI Primer for Emergency Department Radiologists.

The occurrence of acute myelopathy in a nontrauma setting constitutes a medical emergency for which spinal MRI is frequently ordered as the first step in the patient's workup. The emergency department radiologist should be familiar with the common differential diagnoses of acute myelopathy and be able to differentiate compressive from noncompressive causes. The degree of spinal cord compression and presence of an intramedullary T2-hyperintense signal suggestive of an acute cord edema are critical findings for subsequent urgent care such as surgical decompression. Importantly, a delay in diagnosis may lead to permanent disability. In the spinal canal, compressive myelopathy can be localized to the epidural, intradural extramedullary, or intramedullary anatomic spaces. Effacement of the epidural fat and the lesion's relation to the thecal sac help to distinguish an epidural lesion from an intradural lesion. Noncompressive myelopathy manifests as an intramedullary T2-hyperintense signal without an underlying mass and has a wide range of vascular, metabolic, inflammatory, infectious, and demyelinating causes with seemingly overlapping imaging appearances. The differential diagnosis can be refined by considering the location of the abnormal signal intensity within the cord, the longitudinal extent of the disease, and the clinical history and laboratory findings. Use of a compartmental spinal MRI approach in patients with suspected nontraumatic spinal cord injury helps to localize the abnormality to an epidural, intradural extramedullary, or intramedullary space, and when combined with clinical and laboratory findings, aids in refining the diagnosis and determining the appropriate surgical or nonsurgical management.Online supplemental material is available for this article.©RSNA, 2019.

Subtle Imaging Findings Aid the Diagnosis of Adolescent Hereditary Spastic Paraplegia and Ataxia.

PURPOSE: Hereditary spastic paraplegia (HSP) and hereditary spastic ataxia (HSA) are a heterogeneous group of genetic disorders characterized by progressive lower limb spasticity resulting from pyramidal tract dysfunction. By identifying critical imaging findings within the clinical context of spasticity, radiologists are uniquely positioned to recommend specific genetic testing, and thus facilitate diagnosis. METHODS: We present two examples of HSP and HSA that had gone clinically unrecognized for years, and in which magnetic resonance imaging played a critical role in the diagnosis. RESULTS: Radiologists' awareness of HSP and HSA, combined with a critical review of the clinical history and characteristic imaging findings led to specific genetic testing and a definitive diagnosis. CONCLUSION: Awareness of HSP and HSA among radiologists will expedite more accurate diagnosis, explanation of patient symptoms, recommendation for syndrome-specific treatment, and family planning considerations.

Susac's syndrome: Leptomeningeal enhancement on 3D FLAIR MRI.

BACKGROUND: Contrast-enhanced (ce) fluid-attenuated inversion recovery magnetic resonance imaging (FLAIR MRI) has recently been shown to identify leptomeningeal pathology in multiple sclerosis. OBJECTIVE: To demonstrate leptomeningeal enhancement on three-dimensional (3D) FLAIR in a case of Susac's syndrome. METHODS: Leptomeningeal enhancement was correlated with clinical activity over 20 months and compared to retinal fluorescein angiography. RESULTS: The size, number, and location of leptomeningeal enhancement varied over time and generally correlated with symptom severity. The appearance was remarkably similar to that of retinal vasculopathy. CONCLUSION: Ce 3D FLAIR may aid in diagnosis and understanding of pathophysiology in Susac's syndrome and may serve as a biomarker for disease activity.

Transient hemiglossal denervation during acute internal capsule infarct in the setting of dysarthria-clumsy hand syndrome.

A case of MR imaging-documented transient unilateral tongue denervation presenting during acute internal capsule infarction is described. Understanding the corticolingual pathway innervation of the hypoglossal nucleus is essential for explaining these findings. Awareness of the findings in this case will facilitate appropriate diagnosis, provide neuroanatomic explanation, and prevent misdiagnosis.

Anti-tumor necrosis factor alpha-associated multiple sclerosis.

A case of multiple sclerosis presenting during anti-tumor necrosis factor treatment for rheumatoid arthritis is discussed. This association has been reported in the nonradiological literature, but is an important association for radiologists to be aware of, as they may be in a position to first suggest the diagnosis.

Quantifying the impact of seminal vesicle invasion identified using endorectal magnetic resonance imaging on PSA outcome after radiation therapy for patients with clinically localized prostate cancer.

PURPOSE: This study examined the impact that seminal vesicle invasion (SVI), observed on endorectal magnetic resonance imaging (erMRI), had on prostate-specific antigen (PSA) outcome after external beam radiation therapy (EBRT) for patients with clinically localized prostate cancer. METHODS AND MATERIALS: The study cohort was comprised of 250 patients who received 3D conformal radiation therapy without hormones for clinically localized prostate cancer between 1992 and 2001. The primary end point was PSA failure, defined using the American Society for Therapeutic Radiology and Oncology consensus definition. Cox regression multivariable analysis was used to determine the ability of the pretreatment risk group and erMRI SVI to predict for time to PSA failure after EBRT. RESULTS: Both risk group (p(Cox) = 0.001) and erMRI SVI (p(Cox) = 0.003) were independent and significant predictors of time to PSA failure. For patients beyond low risk, 4-year estimates of PSA failure-free survival for erMRI SVI-negative vs. erMRI SVI-positive patients were 68% vs. 33% (p(log-rank) = 0.0014), respectively. CONCLUSION: Patients with clinically localized disease and PSA >10 or biopsy Gleason score >or=7 or clinical T category T2b or T2c who also have erMRI evidence of SVI have PSA outcomes similar to patients with locally advanced prostate cancer after EBRT monotherapy. Consideration should be given to combining EBRT with hormonal therapy in these patients.