Objective: To evaluate simplified intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) for liver lesion characterisation at 3.0 T and to compare it with 1.5 T.
Methods: 3.0-T DWI data from a respiratory-gated MRI sequence with b = 0, 50, 250, and 800 s/mm2 were analysed in 116 lesions (78 patients) and 27 healthy livers. Apparent diffusion coefficient ADC = ADC(0,800) and IVIM-based parameters D1' = ADC(50,800), D2' = ADC(250,800), f1' = f(0,50,800), f2' = f(0,250,800), D*' = D*(0,50,250,800), ADClow = ADC(0,50), and ADCdiff = ADClow-D2' were calculated voxel-wise and analysed on per-patient basis. Results were compared with those of 173 lesions (110 patients) and 40 healthy livers at 1.5 T.
Results: Focal nodular hyperplasias were best discriminated from all other lesions by f1' and haemangiomas by D1' with an area under the curve (AUC) of 0.993 and 1.000, respectively. For discrimination between malignant and benign lesions, ADC was best suited (AUC of 0.968). The combination of D1' and f1' correctly identified more lesions as malignant or benign than the ADC (99.1% vs 88.8%). Discriminatory power for differentiating malignant from benign lesions tended to be higher at 3.0 T than at 1.5 T.
Conclusion: Simplified IVIM is suitable for lesion characterisation at 3.0 T with a trend of superior diagnostic accuracy for discriminating malignant from benign lesions compared with 1.5 T.
Key points: • Simplified IVIM is also suitable for liver lesion characterisation at 3.0 T. • Excellent accuracy was reached for discriminating malignant from benign lesions. • The acquisition of only three b-values (0, 50, 800 s/mm 2 ) is required.
Keywords: Carcinoma, hepatocellular; Diffusion magnetic resonance imaging; Focal nodular hyperplasia; Haemangioma; Liver neoplasms.