Musculoskeletal neoplasms: fast low-angle shot MR imaging with and without Gd-DTPA.

Abstract

In 121 patients, image contrast and contrast-to-noise ratios (C/Ns) obtained with gadolinium diethylene-triaminepentaacetic acid (DTPA)-enhanced and nonenhanced fast low-angle shot (FLASH) sequences were compared with those achieved with spin-echo (SE) sequences. Among FLASH sequences, contrast between neoplasms and muscle was sufficient with a flip angle of 90 degrees following administration of Gd-DTPA but was 61% lower than that with the T2-weighted SE sequence. High contrast levels were obtained between tumors and bone marrow or fat in sclerotic, calcified, and fibrotic lesions with the use of a flip angle of 90 degrees and in lytic lesions with a flip angle of 10 degrees, reaching 66% of the contrast level obtained with the T1-weighted SE sequence. C/N between tumor and surrounding tissue was always significantly lower with FLASH sequences than with the ideal SE sequences usually used for tumor delineation. Thus, a replacement of the T2-weighted SE sequences by FLASH sequences cannot be recommended. A replacement of the T1-weighted SE sequences by FLASH sequences seems possible but does not significantly reduce examination time.