MR imaging assessment of experimental hepatic dysfunction with Mn-DPDP

Efficacy and safety of mangafodipir trisodium (MnDPDP) injection for hepatic MRI in adults: results of the U.S. Multicenter phase III clinical trials. Efficacy of early imaging

The efficacy of contrast-enhanced magnetic resonance imaging (MRI) for detecting and characterizing, or excluding, hepatic masses was assessed in 404 patients, following the intravenous administration of mangafodipir trisodium (MnDPDP) injection, a hepatic MRI contrast agent. An initial contrast-enhanced computed tomography (CT) examination was followed by unenhanced MRI, injection of MnDPDP (5 micromol/kg IV), and enhanced MRI at 15 minutes post injection. Agreement of the radiologic diagnoses with the patients' final diagnoses was higher for enhanced MRI and for the combined unenhanced and enhanced MRI evaluations than for unenhanced MRI alone or enhanced CT using the clinical diagnosis as the gold standard. Mangafodipir-enhanced MRI uniquely provided additional diagnostic information in 48% of the patients, and patient management was consequently altered in 6% of the patients. MnDPDP-enhanced MRI was comparable or superior to unenhanced MRI and enhanced CT for the detection, classification, and diagnosis of focal liver lesions in patients with known or suspected focal liver disease.

MnDPDP enhancement characteristics and differentiation between cirrhotic and noncirrhotic livers

RATIONALE AND OBJECTIVES

The objective was to analyze if liver enhancement with mangafodipir trisodium was influenced by liver cirrhosis.

METHODS

Eighty patients (49 with cirrhotic and 31 with noncirrhotic livers) were studied with spin-echo and spoiled gradient-echo T1-weighted images, before and after administration of mangafodipir trisodium. Hepatic insufficiency was assessed using the Child classification. Image analysis was performed both qualitatively and quantitatively.

RESULTS

Noncirrhotic livers enhanced homogeneously but 37% of cirrhotic livers did not; the difference was significant. Areas corresponding to collapsed fibrous zones enhanced less than the rest of the parenchyma; areas of regenerating nodular zones enhanced more. Signal-to-noise ratios were significantly less for cirrhotic livers on postcontrast spoiled gradient-echo images. Cirrhotic livers had significantly lower relative enhancement ratios than noncirrhotic ones. The Child index and aspartate aminotransferase values were statistically related to the enhancement ratio.

CONCLUSIONS

Mangafodipir trisodium enhancement in cirrhotic livers is related to necrosis and regeneration of the hepatocytes. Cirrhotic livers enhanced less than noncirrhotic ones.

Experimental hepatic dysfunction: evaluation by MRI with Gd-EOB-DTPA

To investigate the potential of gadolinium (Gd)-ethoxybenzyl (EOB)-diethylenetriamine-pentaacetic acid (DTPA) for evaluating liver function, chemically induced hepatitis animal models were studied. The rats in group 1 underwent intraperitoneal administration of 2.0 ml/kg and those in group 2 underwent intraperitoneal administration of .5 ml/kg of 50% (V/V) carbon tetrachloride (CCl4) solution. The rats in group 3 served as controls. For rats of each group, the signal intensity of the liver was measured on T1-weighted spin-echo MR images acquired before and until 60 minutes after an intravenous injection of Gd-EOB-DTPA. The remaining rats in each group underwent indocyanine green test, serologic examination, or measurement of prothrombin time. Liver enhancement was compared with results of the other examinations. The degree of liver enhancement with Gd-EOB-DTPA was decreased and the washout of contrast was prolonged in the CCl4-administered groups. In this animal model, both hepatic dysfunction and liver enhancement were dose-dependent. MRI with Gd-EOB-DTPA has the potential to evaluate hepatic function.

Evaluation of the hepatocyte-specific contrast agent gadobenate dimeglumine for MR imaging of acute hepatitis in a rat model

This work was conducted to test the hypothesis that contrast-enhanced MRI with hepatocyte-specific contrast agents facilitates quantitation and mapping of diffuse liver diseases such as hepatitis and cirrhosis. Gadobenate dimeglumine (Gd-BOPTA/Dimeg, Bracco SpA, Millano, Italy) is a new paramagnetic hepatocyte-specific contrast agent currently undergoing clinical trials. We have assessed the usefulness of gadobenate dimeglumine for the diagnosis of diffuse liver diseases in a rat model of chemically induced hepatitis. The study was based on the measurements of in vivo liver relaxation times as well as on the acquisition of standard SE images. Acute hepatitis considerably reduced the degree of T1 shortening of liver parenchyma caused by intravenous injection of .25 mmol/kg of gadobenate dimeglumine. Analogously, the enhancement of the MRI signal intensity of the liver of rats with hepatitis observed in T1-weighted spin-echo (SE) images was inferior, in terms of both strength and duration, to that recorded in control rats at doses of .25 mmol/kg and .075 mmol/kg of gadobenate dimeglumine. Our results show that gadobenate dimeglumine-enhanced MR imaging has the potential for visualization of hepatitis and for assessment of liver function. Our conclusions differ from those previously published on this subject by other authors. The reasons that led to differing conclusions are discussed.