Comparison of respiratory-triggered T2-weighted turbo spin-echo imaging versus breath-hold T2-weighted turbo spin-echo imaging: distinguishing benign from malignant liver lesions in patients with colorectal cancer.

T2-weighted turbo spin echo sequences are being used as a first sequence for abdominal magnetic resonance imaging in many cases. For oncological patients breath-hold imaging can be difficult. T2-weighted turbo spin echo sequences can be used during breath-hold or during respiratory-triggering. The purpose of our study is to compare a respiratory-triggered fat-suppressed and breath-hold T2-weighted Turbo Spin Echo (RT and BH FS T2w TSE) sequence for focal liver lesions. Prospectively, both T2w TSE sequences were acquired in 40 patients using 1.5T MRI. Qualitatively analysis was performed for image quality, lesion conspicuity, diagnostic confidence, artifacts using two-tailed Wilcoxon signed-ranks test. Quantitative analysis was performed for lesion-to-liver Contrast-to-Noise Ratio (CNR) using two-tailed Student's t-test. Qualitatively, RT FST2wTSE performed significantly (p < 0.05) better than BH FST2wTSE concerning image quality, lesion conspicuity, diagnostic confidence and artifacts. Seventy-eight metastases and 47 hemangiomas were detected on both FST2wTSE sequences. Seven liver metastases and 2 hemangiomas < 10 mm and 3 metastases between 10-20 mm detected on RT FS T2wTSE were only retrospectively detected on BH FS T2wTSE. Diagnostic confidence scores were best using RT FS T2w TSE compared with BH FS T2w TSE. Mean CNR of all lesions, mean CNR of all lesions < 10 mm and mean CNR between hemangiomas and metastases was significantly better using the RT sequence compared with the BH sequence. RT FST2wTSE might perform better than BH FST2wTSE for lesion detection and characterization in this study.