COMPARISON OF HASTE AND SEGMENTED-HASTE SEQUENCES WITH A T2-WEIGHTED FAST SPIN-ECHO SEQUENCE IN THE SCREENING EVALUATION OF THE BRAIN

OBJECTIVE, The purpose of this study was to evaluate the neuroradiolog ic application of half-Fourier acquisition single-shot turbo spin-echo (HASTE) and segmented-HASTE (s-HASTE) sequences in comparison with a T2-weighted fast spin-echo sequence. MATERIALS AND METHODS. First, HAS TE, s-HASTE, and fast spin-echo sequences were evaluated for blurring artifacts with a stationary phantom and for motion artifacts with a mo ving phantom, which repeated constant or intermittent to-and-fro motio ns at variable intervals. Second, 30 consecutive patients with various intracranial diseases were prospectively examined with the three sequ ences. Lesions were classified into four groups according to size and signal intensity on fast spin-echo MR images as follows: large hyperin tense, small hyperintense, small markedly hyperintense, and hypointens e lesions. Signal intensities of the lesion, putamen, and gray matter were compared with the signal intensity of white matter, and contrast- to-noise ratios were calculated. Overall image quality, conspicuity of lesions, delineation of the junction between gray matter and white ma tter, conspicuity of the putamen, and certain types of artifacts were evaluated qualitatively. RESULTS. Ln the phantom study, the HASTE sequ ence was least affected by motion artifacts and the fast spin-echo seq uence was most affected, although the images of the HASTE sequence wer e most degraded by blurring artifacts. In the clinical study, we found no significant differences among the three sequences for contrast-to- noise ratios or conspicuity of large hyperintense and small markedly h yperintense lesions. However, the contrast-to-noise ratios of hypointe nse lesions and gray matter, and the conspicuity of hypointense lesion s were significantly poorer for the HASTE sequence than for the fast s pin-echo sequence. The contrast-to-noise ratios of small hyperintense lesions and the putamen, conspicuity of small hyperintense lesions and putamen, and delineation of the junction between gray matter and whit e matter were significantly poorer for HASTE and s-HASTE sequences tha n for the fast spin-echo sequence. Ghost artifacts, which were observe d during the s-HASTE sequence, were sometimes superimposed on the imag e. CONCLUSION. The HASTE and s-HASTE sequences afford substantial time reduction and also decrease motion artifacts and thus have potential advantages for neuroradiologic application, especially in uncooperativ e or unsedated children. The s-HASTE sequence may be preferable to the HASTE sequence because of fewer blurring artifacts and higher T2 cont rast. However, small hyperintense and hypointense lesions may be overl ooked when HASTE and s-HASTE sequences are used.