Hepatic MR imaging: comparison of RARE derived sequences with conventional sequences for detection and characterization of focal liver lesions |
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Authors: | P Reimer E J Rummeny M Wissing G M Bongartz G Schuierer P E Peters |
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Institution: | 1. Institute of Clinical Radiology, Westfalian Wilhelms-University Muenster, Albert-Schweitzer Stra?e 33, D-48129, Münster, Germany
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Abstract: | Background: We compared two T2-weighted turbo spin echo (TSE) sequences with a T2-weighted conventional SE (CSE) sequence to determine
whether sequences derived from rapid acquisition with relaxation enhancement such as TSE could replace CSE for the detection
and subsequent characterization of focal liver lesions.
Methods: A total of 55 consecutive patients with 107 liver lesions underwent magnetic resonance imaging examinations at 1.5 Tesla,
with a constant imaging protocol. TSE pulse sequences were acquired with eight echo trains (repetition time TR], 4718 ms;
echo time TE], 90 ms; acquisition time TA], 4.03 min; and a symmetric k-space ordering scheme) and 11 echo trains (TR, 4200
ms; TE, 140 ms; TA, 4.40 min; and an asymmetric k-space ordering scheme) and compared with CSE (TR, 2300 ms; TE, 45/90 ms;
TA, 9.53 min). Images were analyzed qualitatively by scoring image quality and artifacts and counting focal liver lesions
by independent reading with consensus obtained for discrepancies. Quantitative analysis was performed by measuring signal-to-noise
(S/N), contrast-to-noise (C/N), and tumor–liver signal intensity (T/L) ratios.
Results: T2-weighted TSE sequences provided better subjective image quality and reduced artifacts as compared with the T2-weighted
CSE sequence. CSE and TSE sequences exhibited no statistically significant differences in liver S/N, lesion–liver C/N (CSE
TE, 90 ms: 18.6 ± 14.0; TSE TE, 90 ms: 16.5 ± 12.9) and the detectability of focal liver lesions. Heavily T2-weighted TSE
with a TE of 140 ms allowed correct characterization of focal liver lesions based on a T/L ratio of 3.0 in 84% of patients.
Conclusions: T2-weighted TSE sequences are as suited as CSE for the detection (TE, 90 ms), and appear to be superior for the characterization
(TE, 140 ms), of focal hepatic lesions. Whether a single sequence, such as a double-echo TSE or a single-echo TSE sequence
with a TE between 110 and 120 ms, might perform both functions as well or better than CSE is unknown. However, because of
time savings, TSE eventually may be preferred over CSE.
Received: 13 December 1994/Accepted after revision: 31 March 1995 |
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Keywords: | : MRI— Hepatic imaging— RARE— Detection— Characterization |
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