Chao-Shiang Li MD, Presenter: Nothing to Disclose

Wen-Chiung Lin MD, Abstract Co-Author: Nothing to Disclose

Marta Braschi MD, Abstract Co-Author: Nothing to Disclose

Peter Florin Hahn MD, PhD, Abstract Co-Author: Nothing to Disclose

Peter Raff Mueller MD, Abstract Co-Author: Consultant, Cook Group Incorporated, Bloomington, IN

Mukesh Gobind Harisinghani MD, Abstract Co-Author: Nothing to Disclose

USPIO enhanced MR imaging has been shown to be an accurate technique for lymph node characterization in patients with various primary tumors. In addition to evaluation of lymph nodes, change of signal intensity was commonly noted in the prostate gland after administration of USPIO. The purpose of this study is to evaluate the signal intensity characteristics of prostate gland with USPIO-enhanced MR imaging.

69 patients (mean age: 62.8±7.6 years) with prostate cancer underwent USPIO-enhanced MR imaging for staging of lymph node metastasis, and were included in this study. The central zones (CZ) and peripheral zones (PZ) on each side of prostate gland were evaluated on fast spin-echo T2-weighted imaging (T2WI) and gradient-refocused echo T2*-weighted MR imaging (T2*WI) at l.5 T before and 24 hours after the intravenous administration of USPIO (2.6-mg Fe/kg body weight). Measurements of signal intensities were performed by use of operator-defined region-of-interest (ROI) cursors. The signal-to-noise ratio (SNR) was calculated by dividing signal intensity of interested zone by the noise of background. The change of SNR referred to percentage of SNR decrease after enhanced by USPIO.

On T2WI, mean change of SNR in right CZ was 9.40±43.3% (mean±standard deviation), and it was -2.92±53.1% in ipsilateral PZ. The mean change of SNR in left CZ was 7.86±43.8%, and it was -2.20±51.0% in ipsilateral PZ. On T2*WI, mean change of SNR in right CZ was -3.17±110%, and it was -20.9±154% in ipsilateral PZ. The mean change of SNR in left CZ was -2.53±96.8%, and it was -20.1±150% in ipsilateral PZ.

The current study demonstrates the trend that uptake of USPIO in the central zone of the prostate gland is greater than that of peripheral zone. Investigation is currently underway to assess the utility of this differential uptake and correlate this with pathologic grade of primary prostate cancer.

The preliminary results are helpful to following investigations of USPIO-enhanced MR imaging of prostate cancer.

Li, C, Lin, W, Braschi, M, Hahn, P, Mueller, P, Harisinghani, M, Ultra-small Superparamagnetic Iron Oxide (USPIO)-enhanced Magnetic Resonance Imaging of Prostate Gland: Preliminary Results.  Radiological Society of North America 2006 Scientific Assembly and Annual Meeting, November 26 - December 1, 2006 ,Chicago IL. http://archive.rsna.org/2006/4440719.html