T2-weighted MR imaging of the abdomen: fast spin-echo vs conventional spin-echo sequences.

OBJECTIVE: The purpose of this study was to compare one optimized T2-weighted fast spin-echo sequence with one T2-weighted conventional spin-echo sequence to determine the impact of fast spin echo on image quality and diagnostic efficacy for evaluation of the abdomen. SUBJECTS AND METHODS: A total of 32 patients with 43 lesions involving various abdominal organs were examined. T2-weighted fast spin-echo (4000/119/4, echo train length = 16, matrix = 256 x 256) and T2-weighted conventional spin-echo (3400-3800/80/2, matrix = 128 x 256) images were compared qualitatively and quantitatively to determine whether the two types of images differed with respect to tissue contrast, conspicuousness of lesions, image quality, and artifacts. RESULTS: The signal intensity of all abdominal structures (except gallbladder and fat) was significantly lower on fast spin-echo images than on conventional spin-echo images. Qualitative liver-to-spleen contrast was significantly reduced on fast spin-echo images, whereas quantitative liver-to-spleen contrast was not significantly different. Blurring of anatomic structures, vascular pulsation, and chemical-shift misregistration artifacts were significantly reduced on fast spin-echo images. The qualitative conspicuousness and contrast-to-noise ratio for all lesions evaluated together were not significantly different (p = .5 and p = .069, respectively) on fast spin-echo vs conventional spin-echo images. However, qualitative conspicuousness and contrast-to-noise ratio of solid lesions were significantly reduced on fast spin-echo images (p = .022 and p = .01, respectively). The contrast-to-noise ratio of cystic lesions was significantly better (p = .002) on fast spin-echo images than on conventional spin-echo images. CONCLUSION: Although the fast spin-echo protocol used in this study provides better image quality and contrast-to-noise ratio for cystic abdominal lesions than does conventional spin echo, the qualitative conspicuousness and contrast-to-noise ratio of solid abdominal lesions are decreased. Fast spin echo provides high-quality images with fewer artifacts in significantly less time than is possible with conventional spin-echo images. Further evaluation is necessary to determine the optimal protocol for T2-weighted fast spin-echo MR imaging of the abdomen.