Inflammatory Infectious Diseases PDF

Conventional MRI Findings Axial T2 images and sagittal FLAIR image: Characteristic MS lesions (“plaques”) are oval or ovoid, often oriented with their long axis perpendicular to the ventricular surface. Contrast enhancing lesions Gadolinium enhancement can serve as a surrogate for disease activity....

Conventional MRI Findings Axial T2 images and sagittal FLAIR image: Characteristic MS lesions (“plaques”) are oval or ovoid, often oriented with their long axis perpendicular to the ventricular surface. Contrast enhancing lesions Gadolinium enhancement can serve as a surrogate for disease activity. Lesions which enhance on postgadolinium T1-weighted images correlate with acute or subacute demyelination. T1 hypointense lesions Some chronic MS plaques, also known as “black holes”, appear hypointense on pre- and post-contrast T1-weighted images. These “black holes” have been found to represent irreversible axonal loss. Some studies have shown a correlation between volume of these lesions and clinical disability (though this is not clearly established). Tumefactive MS Some MS lesions can appear atypical and demonstrate mass effect with incomplete peripheral enhancement. These “tumefactive” lesions can be difficult to differentiate from tumor or abscess. Post-contrast T1 images (axial, coronal) Images courtesy of Mario Cirillo, MD Optic nerve involvement MS is the most common cause of optic neuritis, and optic neuritis is one of the most common clinical syndromes in MS patients at initial presentation. 50% of patients with optic neuritis will develop MS. Most frequent finding: Leptomeningeal enhancement on CT or MRI. May identify complications: Hydrocephalus Abscess Cerebritis Thrombosis Infarcts Ventriculitis