RAPIDLY ENHANCING HEPATIC HEMANGIOMAS AT MRI - DISTINCTION FROM MALIGNANCIES WITH T2-WEIGHTED IMAGES

The purpose of this study is to describe a subset of atypical hepatic hemangiomas that enhance rapidly and diffusely and to determine whethe r heavily T2-weighted images could distinguish between atypically enha ncing liver hemangiomas and hypervascular malignancies. A retrospectiv e search of MR records identified seven patients with liver hemangioma s that demonstrated diffuse early enhancement and 23 patients with bio psy-proven malignant liver lesions that were hypervascular on dynamic gadolinium-enhanced MR images. Quantitative analysis of signal intensi ty measurements was performed on the T2-weighted images, heavily T2-we ighted (TE > 140), and dynamic gadolinium-enhanced images. Blinded rea der comparison of the T2-weighted images and gadolinium-enhanced image s was performed, Hypervascular hemangiomas enhanced to a greater degre e than hypervascular malignant liver lesions on the early phase gadoli nium-enhanced images. Perilesional parenchymal enhancement was demonst rated in five cases of rapidly enhancing hemangiomas. Signal intensity and contrast-to-noise ratios on the heavily T2-weighted images of the hemangiomas were significantly greater than that of the hypervascular malignant lesions (p < .05), Hemangiomas were differentiated from the hypervascular malignant liver lesions with high accuracy (97-100%) by three blinded readers based on the T2-weighted images. A subset of he mangiomas have atypical rapid diffuse enhancement on dynamic gadoliniu m-enhanced images. These atypical hemangiomas can be distinguished fro m hypervascular malignant liver lesions on T2-weighted MR images.