Tumor Contrast Enhancement and Whole-Body Elimination of the Manganese-Based Magnetic Resonance Imaging Contrast Agent Mn-PyC3A. Issue 11 (November 2019)

• Record Type: Journal Article
• Authors: Erstad, Derek J.; Ramsay, Ian A.; Jordan, Veronica Clavijo; Sojoodi, Mozhdeh; Fuchs, Bryan C.; Tanabe, Kenneth K.; Caravan, Peter; Gale, Eric M.
• Is Part Of: Investigative radiology. Volume 54:Issue 11(2019)
• Publication Date: 2019-11
• Subjects: MRI contrast agent -- manganese -- Mn-PyC3A -- gadolinium -- biodistribution; Diagnosis, Radioscopic -- Periodicals; Radiology, Medical -- Periodicals; 616.0757
• DOI: 10.1097/RLI.0000000000000593
• Languages: English
• ISSNs: 0020-9996

Abstract

Abstract : Objectives: The goals of this study were to compare the efficacy of the new manganese-based magnetic resonance imaging (MRI) contrast agent Mn-PyC3A to the commercial gadolinium-based agents Gd-DOTA and to Gd-EOB-DTPA to detect tumors in murine models of breast cancer and metastatic liver disease, respectively, and to quantify the fractional excretion and elimination of Mn-PyC3A in rats. Methods: T1-weighted contrast-enhanced MRI with 0.1 mmol/kg Mn-PyC3A was compared with 0.1 mmol/kg Gd-DOTA in a breast cancer mouse model (n = 8) and to 0.025 mmol/kg Gd-EOB-DTPA in a liver metastasis mouse model (n = 6). The fractional excretion, 1-day biodistribution, and 7-day biodistribution in rats after injection of 2.0 mmol/kg [ 52 Mn]Mn-PyC3A or Gd-DOTA were quantified by 52 Mn gamma counting or Gd elemental analysis. Imaging data were compared with a paired t test; biodistribution data were compared with an unpaired t test. Results: The postinjection-preinjection increases in tumor-to-muscle contrast-to-noise ratio (ΔCNR) 3 minutes after injection of Mn-PyC3A and Gd-DOTA (mean ± standard deviation) were 17 ± 3.8 and 20 ± 4.4, respectively ( P = 0.34). Liver-to-tumor ΔCNR values at 8 minutes postinjection of Mn-PyC3A and Gd-EOB-DTPA were 28 ± 9.0 and 48 ± 23, respectively ( P = 0.11). Mn-PyC3A is eliminated with 85% into the urine and 15% into the feces after administration to rats. The percentage of the injected doses (%ID) of Mn and Gd recovered in tissues after 1 day were 0.32 ± 0.12 and 0.57 ± 0.12, respectively ( P = 0.0030), and after 7 days were 0.058 ± 0.051 and 0.19 ± 0.052, respectively ( P < 0.0001). Conclusions: Mn-PyC3A provides comparable tumor contrast enhancement to Gd-DOTA in a mouse breast cancer model and is more completely eliminated than Gd-DOTA; partial hepatobiliary elimination of Mn-PyC3A enables conspicuous delayed phase visualization of liver metastases. Abstract : Supplemental digital content is available in the text.