Improved differentiation between hepatic hemangioma and metastases on diffusion-weighted MRI by measurement of standard deviation of apparent diffusion coefficient.

BACKGROUND: Diffusion-weighted magnetic resonance imaging (DW-MR) can be useful in the differentiation of hemangiomata from liver metastasis, but improved methods other than by mean apparent diffusion coefficient (mADC) are needed.

METHODS: A retrospective review identified 109 metastatic liver lesions and 86 hemangiomata in 128 patients who had undergone DW-MR. For each lesion, mADC and the standard deviation of the mean ADC (sdADC) were recorded and compared by receiver operating characteristic analysis.

RESULTS: Mean mADC was higher in benign hemangiomata (1.52±0.12 mm(2)/s) than in liver metastases (1.33±0.18 mm(2)/s), but there was significant overlap in values. The mean sdADC was lower in hemangiomata (101±17 mm(2)/s) than metastases (245±25 mm(2)/s) and demonstrated no overlap in values, which was significantly different (P<.0001).

CONCLUSIONS: Hemangiomata may be better able to be differentiated from liver metastases on the basis of sdADC than by mADC, although further studies are needed.