Klinische Wertigkeit von Mn-DPDP: Neues paramagnetisches hepatobiliäres Kontrastmittel für die Magnetresonanztomographie der Leber

Abstract

In an open prospective study the tolerance and diagnostic value of the new hepatobiliary contrast agent Mn-DPDP in MR imaging was evaluated in 20 patients suspected of having focal liver lesions. T1- and T2-weighted spin-echo sequences and T1-weighted gradient-echo sequences were obtained before and after intravenous application of Mn-DPDP. In all patients the signal to noise (S/N) values of normal liver tissue increased significantly after application of Mn-DPDP. All focal lesions could be better localized and differentiated due to increased contrast to noise ratios of lesion to liver. Pathological examination revealed in 14 patients malignant and in 5 patients benign liver lesions; one patient had no pathological findings. In metastatic disease of the liver 25-120% more lesions could be detected in MRI after Mn-DPDP-application, compared with the unenhanced images. In 5 patients the lesions showed significant enhancement of Mn-DPDP (2 cirrhotic nodules, 2 hepatocellular carcinomas, 1 focal nodular hyperplasia). Our preliminary results indicate that Mn-DPDP is a well-tolerated contrast agent useful for the detection and differentiation of liver lesions in MR imaging.

Metal-Based Complexes as Pharmaceuticals for Molecular Imaging of the Liver

“…Prior to the development of Gd-EOB-DTPA, the Mn(II) complex of DPDP [86]—mangafodipir (Figure 2)—was clinically approved in the 1990s as a hepatobiliary CA. Mangafodipir-enhanced MRI improved the identification of HCC [18,87,88] and more generally the detection, classification, and diagnosis of focal liver lesions (Figure 3) [24,89,90,91,92], including primary and metastatic liver tumors [93,94]. Excellent articles have been published comparing liver-specific Gd-EOB-DTPA, Gd-BOBPTA, and Mn-DPDP with detailed descriptions of detection rates, contrast enhancement on various types of lesions, and influence on the respective acquisition techniques [90].…”

“…Free Mn(II) has been associated with extensive production of reactive oxygen species (ROS) [104,105], reactive nitrogen species (RNS) [106], and also with mitochondrial manganese superoxide dismutase (MnSOD) mimetic activities [107]. Also, possible adverse cardiovascular responses such as negative inotropy and vasodilation were suspected to occur based on the fact that Mn(II)—particularly if released at high extracellular concentrations—may act as a clinically-relevant Ca(II) antagonist [88,108,109]. However, early studies focused on toxicity and cardiovascular effects have concluded that Mn-DPDP is generally safe in normal clinical use [90,110,111].…”