FIG 2.

Representative MRIs from 5 patients with PML demonstrating the essential features of the MR imaging shrimp sign. Each row represents images taken from 1 patient, numbered cases 1–5: T2 axial (A), T1 axial (B), and T1 sagittal images (C). White arrows identify the white matter lesion; black arrows, the dentate nucleus. FLAIR axial (D), T1 axial (E), T1 sagittal (F), FLAIR axial (G), T2 axial (H), T1 coronal (I), FLAIR axial (J), T2 axial (K), T1 sagittal (L), T2 axial (M), FLAIR axial (N), and T1 sagittal (O) views. In case 5, the bilaterally symmetric shrimp sign is somewhat atypical in this patient with PML in the setting of confirmed HIV positive for CSF-JCV.