Use of Contrast Agents in the Detection and Differentiation of Focal Liver Lesions by Mr Imaging: Gd-DTPA, Mn-DPDP and Iron Oxide

Abstract

MR imaging has a higher sensitivity in the detection of focal liver lesions than CT1, 2, 3. Of particular interest is a paper published by Heiken and co-workers4, who compared the sensitivities of contrast-enhanced CT, CT during arterial portography (CTAP) and MR imaging, and correlated the results with histopathological findings. The highest sensitivity was found for CTAP (81%), followed by MR imaging (57%) and contrastenhanced CT (38%). The rather high error rates of MR imaging and contrast-enhanced CT were due to the poor visualization of small metastases with a diameter of less than 1 cm. Since, however, CTAP is a complex and invasive procedure, research in this area is aimed at improving the sensitivity of liver MR imaging by new technical developments and by the use of tissuespecific contrast agents. MR imaging has a remarkably high diagnostic accuracy in the differentiation of liver tumours, since the information displayed on MR images is far superior to that obtained by ultrasound or CT. In the clinical setting, this advantage of MR imaging is of particular importance in differentiating haemangiomas and metastases — the most frequent benign and malignant tumours of the liver5, 6, 7.