Tumor enhancement using Mn-metalloporphyrin in mice: magnetic resonance imaging and histopathologic correlation.

Abstract

To determine the signal enhancement characteristics of tumors after administration of a metalloporphyrin derivative, HOP-9P (13, 17-bis (1-carboxypropionyl) carbamoylethyl-3, 8-bis (1-phenylpropyloxyethyl)-2, 7, 12, 18-tetramethyl-porphyrinato manganese (III)) and to determine whether HOP-9P is tumor-necrosis specific. Ten C3H/He mice bearing a SCC VII tumor in the right flank were examined using T1-weighted conventional spin echo magnetic resonance (MR) imaging before contrast injection, and five minutes, one hour, and 24 hours after intravenous administration of 0.1 mmol/kg of HOP-9P. Following the imaging schedule, the mice were sacrificed, and sectioned in the same axial planes as the MR images. Based on an MR imaging-histopathologic correlation, mean signal intensities were measured, and signal-to-noise ratios (SNR) were calculated for both pure viable component and admixture of necrotic and viable component of the tumor. Mean SNR of the pure viable component peaked at one hour (35.0 +/- 3.8) and maintained that level until 24 hours (34.6 +/- 3.6). Mean SNR of the admixture of necrotic and viable component peaked at 24 hours (44.3 +/- 12.1). Although different enhancement patterns were seen between the pure viable component and the admixture of necrotic and viable component, HOP-9P enhanced both of the two components.