Diagnostic performance of diffusion weighted imaging for early response assessment after Y-90 transarterial radioembolization of Hepatocellular Carcinoma (HCC) - A systematic review and meta-analysis.

[OBJECTIVE] To systematically determine the diagnostic performance of diffusion weighted imaging (DWI) in early imaging assessment following Y-90 transarterial radioembolization (TARE) of HCC.

[MATERIALS AND METHODS] Searches were conducted in PubMed and Cochrane library electronic databases up to July 2024 to identify original studies that reported the diagnostic performance of DWI/apparent diffusion coefficient (DWI/ADC) for assessing early treatment response following TARE. The summary measures of diagnostic accuracy were estimated using bivariate random effect meta-analysis.

[RESULTS] Our search identified 194 titles, of which 5 studies with data from 104 patients were included in the meta-analysis. The pooled sensitivity and specificity were 0.90 (95%-confidence interval [CI] 0.75,0.96) and 0.81 (95%-CI 0.58,0.92) with a diagnostic odds ratio (DOR) of 45.4 (95% CI 10.2, 132). The area under the summary receiver-operating characteristic curve was 0.919 (95%-CI 0.708,0.924). Exploratory analysis of predictive values projected DWI/ADC to have a NPV of 46.4% (95%-CI 26.8%,69.4%) and projected PPV of 97.6% (95%-CI 95.1%,99.0%), assuming a 90% treatment response rate. The diagnostic performance for early response assessment was comparable with that of traditional imaging criteria reported in literature.

[CONCLUSION] Restricted diffusion has high diagnostic accuracy in early response assessment after TARE. Our study validates the inclusion of restricted diffusion as an ancillary criterion in the LI-RADS TR 2024 algorithm for radiation-based treatment.