Other lesions, however, may be isointense on T2-weighted images but appear as slightly hypointense on T1-weighted images.
Radiology images of the diffuse lymphomatous form of non-Hodgkin’s lymphoma is isointense on the unenhanced T2-weighted image (a). Dilatation of the bile ducts can be seen without depiction of an underlying mass. Conversely, T1- weighted (b) and T1-weighted fat-suppressed (c) images reveal the presence of a distinct tumor that is hypointense compared to the normal liver parenchyma. The tumor shows homogeneous enhancement on dynamic T1-weighted fat-suppressed images (d, e) after the injection of Gd-BOPTA. Note that veins can be seen traversing the lesion without invasion or distortion (arrows in e). The tumor is markedly hypointense with a more nodular appearance on the T1-weighted image (f) acquired during the hepatobiliary phase after Gd-BOPTA administration. On a corresponding MRC image (g) dilatation of the bile ducts towards the liver hilum is visible.