Objective: The purpose of this study was to compare three free-breathing T2-weighted MRI sequences in the evaluation of focal liver lesions.
Materials and methods: Forty-nine patients with 86 focal liver lesions (56 malignant, 30 benign) underwent liver MRI with free-breathing sequences: turbo spin-echo (TSE) with navigator-triggered prospective acquisition correction (PACE), respiration-triggered TSE, and HASTE with navigator-triggered PACE. The images were retrospectively reviewed by two independent observers. Diagnostic performance was evaluated with receiver operating characteristics and sensitivity. The images were assessed quantitatively by measurement of the liver signal-to-noise ratio (SNR) and the lesion-to-liver contrast-to-noise ratio (CNR).
Results: The PACE TSE sequence had better receiver operating characteristic curves for lesion detection and characterization than did the respiration-triggered TSE sequence, but the difference was not statistically significant (p > 0.05). The PACE TSE sequence had a significantly greater area under the curve for lesion detection (p < 0.01) and lesion characterization (p < 0.001) than did the PACE HASTE sequence. The composite sensitivity of the PACE TSE sequence for lesion detection was significantly higher than that of respiration-triggered TSE (p < 0.05) and PACE HASTE (p < 0.01). The mean signal-to-noise ratio for liver and the contrast-to-noise ratio for hepatic lesions were higher with the PACE HASTE than with the other sequences.
Conclusion: The navigator-triggered PACE technique is a valid method for T2-weighted MRI of the liver and may replace conventional respiration-triggered techniques.