Purpose

To investigate the diagnostic value of whole-liver volume histogram analysis of diffusion kurtosis imaging (DKI) metrics in acute cellular rejection (ACR) after orthotopic liver transplantation (OLT).

Method

During 2014 to 2019, 109 patients underwent MR examination with DKI sequence following OLT. A total of 18 patients were diagnosed with ACR (reference standard: biopsy). The remaining 91 patients were as follows: 56 with biliary complications (reference standard: ERC or PTC), 11 with vascular complications (reference standard: surgery or DSA), 2 with drug induced liver injury (DILI), 13 normal (excluded), and 9 tumor recurrence (excluded). Finally 87 patients were included in this study. They were divided into the ACR group and non-ACR group. For each patient, DKI was performed with a 3.0T MRI system (MAGNETOM Trio 3.0T, Siemens Medical Solutions, Erlangen, Germany) with b values of 0, 200, 500, 1000, 1500, and 2000 sec/mm2. Corrected diffusion (D), Kurtosis (K), and apparent diffusion coefficient (ADC) values were measured using dedicated software (Body Diffusion Toolbox, Siemens) with whole-liver volume histogram analysis. Mean, median, skewness, kurtosis, the 25th and 75th percentiles were generated and compared. Student's t-test or Mann-Whitney U-test, and receiver operating characteristic (ROC) curves were used for statistical analysis.

Results

Mean, median, 25th, and 75th percentiles of D values were significantly lower in the ACR group than those in the non-ACR group (P = 0.012-0.027). Mean, median, skewness, 25th, and 75th percentiles of K values in the ACR group were significantly higher compared to those in the non-ACR group (P = 0.003-0.022). No significance were found in ADC parameters between the ACR and non-ACR group. Regarding the comparison of the diagnostic performance of all statistically significant histogram parameters, K75th showed the highest AUC value of 0.895, and the corresponding values for sensitivity and specificity were 0.947 and 0.789, respectively.

Conclusion

DKI metrics with whole-liver volume histogram analysis show a promising potential in diagnosing ACR after OLT compared to traditional imaging modalities.

Acknowledgements

We thank Prof. Bingsheng Huang and his team for providing help with data postprocessing.

References

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