Enhancement of the normal pancreas: comparison of manganese-DPDP and gadolinium chelate

Abstract

The purpose of this paper was to compare manganese-DPDP (Mn-DPDP) and gadolinium chelate (Gd-DTPA) contrast agents for enhancement of the normal pancreas. A total of 14 patients with focal liver disease underwent Mn-DPDP and Gd-DTPA-enhanced 1.5T MR examinations using spoiled gradient-echo (FLASH) technique at tw separate times. Contrast agents were injected according to the currently recommended practices: GD-DTPA was injected as a rapid bolus injection in a dosage of 0.1 mmol/kg, and Mn-DPDP was injected as a slow IV injection in a dosage of 5 μmol/kg. Quantitative region of interest measurements were made in 11 patients, and percent contrast enhancement of the pancreas and pancreas-fat signal-to noise ratios (SNR) were determined for each agent. Images were also evaluated qualitatively by consensus reading of two investigators and overall scan quality was rated on a scale from 1 (poor) to 4 (very good). Enhancement of the pancreas immediately post Gd-DTPA was significantly higher than 15 min post Mn-DPDP (73.3 vs 36.3%;p = 0.003). On postcontrast images the pancreas-fat SNR measurements were 7.7 (i.e., pancreas higher in signal than fat) and 6.1 for Gd-DTPA and Mn-DPDP, respectively, which was significantly different (p < 0.001). Imagine quality was rated as 3.1 and 2.5 for Gd-DTPA- and Mn-DPDP-enhanced images respectively. The normal pancreas enhances significantly more with Gd-DTPA than with Mn-DPDP administered under the conditions of this study. Overall image quality is also greater on the Gd-DTPA-enhanced images.