Comparing lesion detection of infratentorial multiple sclerosis lesions between T2-weighted spin-echo, 2D-FLAIR, and 3D-FLAIR sequences.

PURPOSE: Infratentorial lesions in patients with multiple sclerosis are associated with long-term disability. Two-dimensional fluid-attenuated inversion recovery demonstrates poor infratentorial lesion detection when compared to T2-weighted spin echo. Evidence of improved detection with 3D fluid-attenuated inversion recovery has been conflicting. This study compares the infratentorial lesion detection performance, observer performance, and signal and contrast properties between T2-weighted spin echo, 2D, and 3D fluid-attenuated inversion recovery. METHODS: Two board-certified radiologists independently reviewed and counted infratentorial lesions from 85 brain MRIs in patients with clinically definite multiple sclerosis and concurrent 3D, 2D fluid-attenuated inversion recovery, and T2-weighted spin echo sequences. Contrast-to-noise and signal-to-noise ratios were measured for 25 MRIs. Wilcoxon signed-rank test was used for pairwise comparisons of the combined average infratentorial lesion count, contrast-to-noise, and signal-to-noise ratios, and was adjusted for three pairwise comparisons using Bonferroni correction. A corrected p value < 0.05 was considered statistically significant. RESULTS: The number of lesions on 3D fluid-attenuated inversion recovery was significantly higher than those on 2D (p < 0.001) and T2-weighted spin echo (p < 0.001). Results of contrast-to-noise and signal-to-noise ratios were overall mixed and predominantly not concordant with lesion count findings, with T2-weighted spin echo demonstrating the highest signal-to-noise ratios and contrast-to-noise ratio of lesion compared with white matter but the lowest contrast-to-noise ratio of lesion compared with gray matter. CONCLUSION: The 3D fluid-attenuated inversion recovery sequence addresses the disadvantage of poor infratentorial lesion detection on 2D, while still maintaining the advantage over T2-weighted spin echo in the detection of lesions adjacent to the cerebrospinal fluid.

Spectrum of MRI brain lesion patterns in neuromyelitis optica spectrum disorder: a pictorial review.

Neuromyelitis optica is a neurotropic autoimmune inflammatory disease of the central nervous system traditionally thought to exclusively involve the optic nerves and spinal cord. With the discovery of the disease-specific aquaporin-4 antibody and the increasing recognition of clinical and characteristic imaging patterns of brain involvement in what is now termed neuromyelitis optica spectrum disorder (NMOSD), MRI now plays a greater role in diagnosis of NMOSD based on the 2015 consensus criteria and in distinguishing it from other inflammatory disorders, particularly multiple sclerosis (MS). Several brain lesion patterns are highly suggestive of NMOSD, whereas others may serve as red flags. Specifically, long corticospinal lesions, hemispheric cerebral white matter lesions and periependymal lesions in the diencephalon, dorsal brainstem and white matter adjacent to lateral ventricles are typical of NMOSD. In contrast, juxtacortical, cortical, or lesions perpendicularly oriented to the surface of the lateral ventricle suggests MS as the diagnosis. Ultimately, a strong recognition of the spectrum of MRI brain findings in NMOSD is essential for accurate diagnosis, and particularly in differentiating from MS. This pictorial review highlights the spectrum of characteristic brain lesion patterns that may be seen in NMOSD and further delineates findings that may help distinguish it from MS.

Imaging spectrum of immunomodulating, chemotherapeutic and radiation therapy-related intracranial effects.

OBJECTIVE: A wide range of treatment-related side effects result in specific neurologic symptoms and signs and neuroimaging features. Even to the most seasoned neuroradiologist, elucidating therapy-related side effects from other common mimics can be challenging. We provide a pictorial survey of some common and uncommon medication-induced and therapy-related neuroimaging manifestations, discuss pathophysiology and common pitfalls in imaging and diagnosis. METHODS: A case-based review is utilized to depict scenarios on a routine basis in a general radiology or neuroradiology practice such as medication-induced posterior reversible encephalopathy syndrome to the more challenging cases of pseudoprogression and pseudoregression in temozolmide and bevacizumab therapy in gliobastoma treatment protocols. CONCLUSION: Knowledge of the treatment-induced imaging abnormalities is essential in the accurate interpretation and diagnosis from the most routine to most challenging of clinical situations. We provide a pictorial review for the radiologist to employ in order to be an invaluable provider to our clinical colleagues and patients.