A retrospective analysis of the results of ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI) of 24 cases (28 lesions) of proven focal nodular hyperplasia (FNH) is presented. While US exhibited nonspecific features, CT frequently showed characteristic features: hypodensity on precontrast scans (69%), transient immediate enhancement after bolus injection (96%), and homogeneity (85%). A scar was noted in 31% of the cases. The typical MR triad of isointensity on T1- and/or T2-weighted (T2-WI), homogeneity, and a scar which shows hyperintensity on T2-WI was seen in only 12% of our cases. The most common finding was homogeneity (94%). In two cases the scar was hypointense on T2-WI. To our knowledge, this finding has not been described before. We conclude that the features of FNH, although fairly constant, are at times indistinguishable from those of other hepatic tumors, such as hepatic adenoma (HA), fibrolamellar hepatocellular carcinoma (FLHCC), small hepatocellular carcinoma, and a hyperplastic nodule. Therefore, a multimodality approach is essential for the correct diagnosis in order to prevent unnecessary surgery.

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Since well-known grading parameters such as cellularity, mitotic rate, matrix and presence of necrosis all influence MRI signal intensity, the value of MRI in predicting malignancy is potentially high. To assess this value we studied retrospectively the findings in 141 soft tissue tumours (84 benign, 57 malignant) and evaluated a wide variety of MRI features (size, margins, signal homogeneity, shape, signal intensity, neurovascular and bone involvement, degree and pattern of enhancement and evidence of necrosis after injection of Gd-DTPA). Statistical analysis was carried out to determine accuracy of parameters individually and in combination, for predicting malignancy. Highest sensitivity was obtained for "absence of low signal intensity on T2" (100%), "mean diameter greater than 33 mm" (90%), and "inhomogeneous signal on T1" (88%). Highest specificity was obtained for "evidence of necrosis" (98%), "bone or neurovascular involvement or metastases" (94%), and "mean diameter greater than 66 mm" (87%). Association of best sensitivity and specificity was seen for "absence of low signal intensity on T2", "signal inhomogeneity on T1", and "mean diameter of the lesion greater than 33 mm" (81 and 81%).

The main difference between macrocyclic Gd-DOTA and linear Gd-DTPA complexes is the greater stability of the former which theoretically might reduce biological interactions in man. To evaluate the clinical relevance of this property, 300 unselected neurological patients were included in a randomised double-blind comparison involving five European centres, focused mainly on the tolerance of these two contrast media. Clinical tolerance was assessed immediately after the procedure and 24 h later. Adverse events were found with a similar frequency in the two groups (17.3% for Gd-DOTA and 19.3% for Gd-DTPA). Minor neurological symptoms were the most frequent (48.6%) headache being the most common (29.2% of adverse events). No difference in efficacy was found.