Comparison of acquired diffusion weighted imaging and computed diffusion weighted imaging for detection of hepatic metastases

ObjectiveTo compare the accuracy of acquired diffusion weighted imaging (DWI) (b = 1000 s/mm2) with that of computed DWI (b = 1000 s/mm2) for the detection of hepatic metastases.MethodsTwo hundred and sixty patients underwent abdominal magnetic resonance imaging (MRI) at 3.0 T for the evaluation of hepatic metastasis, including T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), heavily T2WI, DWI with b-values of 0, 500, 1000 s/mm2, and three-dimensional dynamic contrast-enhanced MRI with gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA), and 190 patients were included in the final study. Computed DWI (=1000 s/mm2) was synthesized from lower b-values (b = 0 and 500 s/mm2). Two groups were assigned and compared: group A (acquired DWI) and group B (computed DWI). Diagnostic performance using each imaging set was evaluated by receiver operating characteristic (ROC) curve analysis.ResultsA total of 76 hepatic metastases were confirmed. The area under the ROC curve (Az) of group A was larger than that of group B (Observer 1; 0.919–0.915, Observer 2; 0.926–0.901), but there were no significant differences (observer 1, P = 0.500; observer 2, P = 0.190). There were 5 metastases visualized in group A, but these were difficult to detect in group B. However, there were 2 metastases that were better visualized in group B than in group A.ConclusionThere were no significant differences between acquired DWI and computed DWI in the detection of hepatic metastasis.