UNSELECTED BRAIN 0.5-T MR-IMAGING - COMPARISON OF LESION DETECTION AND CHARACTERIZATION WITH 3 T2-WEIGHTED SEQUENCES

PURPOSE: To compare the diagnostic values of three T2-weighted sequenc es in unselected brain 0.5-T magnetic resonance (MR) imaging examinati ons. MATERIALS AND METHODS: MR imaging was performed in 102 patients b ecause of neurologic symptoms or to follow up ''previously known disea se.'' The protocol comprised three T2-weighted sequences: turbo spin-e cho (SE), turbo fluid-attenuated inversion-recover (FLAIR), and gradie nt and SE (GRASE) sequences. In a prospective, blinded analysis, seque nces were compared quantitatively and qualitatively by three independe nt readers for lesion detection and characterization.RESULTS: Twenty-f our patients had normal findings, and 78 had abnormal findings, with 1 21 final diagnosis. Quantitatively, the ''white'' cerebrospinal fluid (CSF) sequences, turbo SE and GRASE, had higher contrast-to-noise rati os (CNRs) than the ''black,'' CSF sequence, FLAIR, with respect to the signal intensity of white matter, but lower CNRs than FLAIR with resp ect to the signal intensity of CSF. Qualitatively, for lesion detectio n, sensitivity and accuracy were significantly higher for FLAIR than f or turbo SE or GRASE (P < .05); there was no statistically significant difference between turbo SE and GRASE. For lesion characterization, F LAIR was significantly superior to GRASE and turbo SE for white matter disease (P < .05) superior to only turbo SE (P < .05) for vascular di sease, and not superior to GRASE or turbo SE for tumors. CONCLUSION: T he black CSF T2-weighted turbo FLAIR sequence is a useful adjunct to t he usual white CSF T2-weighted sequences in unselected brain 0.5-T MR imaging.