Performance of simultaneous multislice diffusion-weighted imaging using monoexponential, intravoxel incoherent motion, and diffusion kurtosis models: assessment of microvascular invasion and histologic grade in hepatocellular carcinoma.

Objectives: This study aimed to evaluate the diagnostic performance of simultaneous multislice (SMS) acquisition combined with monoexponential, intravoxel incoherent motion (IVIM), and diffusion kurtosis imaging (DKI) models for predicting microvascular invasion (MVI) and histologic grade in hepatocellular carcinoma (HCC).

Materials and methods: A prospective study was conducted with 77 HCC patients. Diffusion-weighted imaging (DWI), IVIM, and DKI were performed on a 3T MRI using both SMS and conventional sequences. The values of diffusion parameters (ADC, D, D*, f, MD, and MK) were compared among SMS and conventional sequences, between MVI-positive and MVI-negative groups, and between high-grade and low-grade HCC groups. Receiver operating characteristic (ROC) curves were used to assess the diagnostic performance of diffusion parameters in predicting MVI and histologic grade. Inter-reader consistency was evaluated using intraclass correlation coefficients (ICC).

Results: Among the 77 patients, 29.9% were MVI-positive and 35.1% had high-grade HCC. SMS reduced scanning time by up to 44.44%. Most diffusion parameters were similar between SMS and conventional sequences, except for slightly lower ADC and f in SMS. MVI-positive and high-grade HCC cases showed lower ADC, D, D*, and MD values and higher MK values. The ICC ranged from 0.702 to 0.879. SMS-MK demonstrated the highest diagnostic performance with an AUC of 0.92 for MVI and 0.86 for histologic grade.

Conclusions: SMS acquisition, integrated with IVIM and DKI, is a feasible imaging method for preoperative evaluation of MVI and histologic grade in HCC, offering a faster alternative to conventional methods without compromising diagnostic performance.