Simultaneous multi-slice diffusion weighted imaging of hepatocellular carcinoma at 3.0 T: Comparison of breath-hold, free-breathing, and respiratory-triggered techniques.

PURPOSE: This study aimed to evaluate the performance of simultaneous multi-slice diffusion weighted imaging (SMS-DWI) using breath-hold (BH), free-breathing (FB), and respiratory-triggered (RT) breathing schemes in patients with hepatocellular carcinoma (HCC), focusing on image quality and apparent diffusion coefficient (ADC) repeatability.

METHODS

This prospective study consecutively enrolled HCC patients between October 2020 and March 2023, based on specific inclusion and exclusion criteria. The patients underwent BH-SMS-DWI, FB-SMS-DWI and RT-SMS-DWI at b-values of 50, 400, and 800 s/mm2. Image quality was assessed qualitatively using a 5-point Likert scale. Besides, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and ADC values were quantitatively measured. To evaluate the ADC repeatability, SMS-DWI scans were performed twice for each breathing scheme. The intraclass correlation coefficient (ICC) and test-retest variability (TRV) were used for assessment.

RESULTS

A total of 172 HCC patients with 189 HCC lesions were included for analysis. BH-SMS-DWI showed the shortest scan time but reduced image quality at high b-values (b = 800 s/mm2) compared to RT-SMS-DWI and FB-SMS-DWI. At b = 800 s/mm2, BH-SMS-DWI exhibited significantly lower overall image quality (3.37 ± 0.67, P < 0.001) compared to both RT-SMS-DWI (3.65 ± 0.69) and FB-SMS-DWI (3.63 ± 0.65), with no significant difference between them (P > 0.990). In addition, it also demonstrated inferior SNRs for both liver and tumor compared to RT-SMS-DWI (liver: 118.36 vs. 183.08, P < 0.001; tumor: 247.41 vs. 389.23, P < 0.001) and FB-SMS-DWI (liver: 118.36 vs. 161.52, P < 0.001; tumor: 247.41 vs. 323.48, P < 0.001). There were no significant differences in tumor ADC values across three breathing schemes. BH-SMS-DWI demonstrated the highest ADC repeatability (ICC: 0.86, 95% CI: 0.84-0.91; TRV: 9.17, 95% CI: 7.21-16.23), followed by FB-SMS-DWI (ICC: 0.83, 95% CI: 0.76-0.87; TRV: 14.27, 95% CI: 11.34-21.17), and RT-SMS-DWI (ICC: 0.80, 95% CI: 0.75-0.86; TRV: 14.36, 95% CI: 12.57-23.31).

CONCLUSION

FB-SMS-DWI is recommended as the most reliable and efficient option for clinical HCC imaging. BH-SMS-DWI, with superior ADC repeatability, is preferred for treatment monitoring and longitudinal follow-up in patients with sufficient breath-holding capability.