Haesun Choi MD, Presenter: Nothing to Disclose

X J Zhou PhD, Abstract Co-Author: Nothing to Disclose

Jingfei Ma PhD, Abstract Co-Author: Nothing to Disclose

Use of endorectal coil for MRS allows us to detect important microscopic metabolites, such as choline and citrate, of prostate tissue. A major limitation of this technique is the suboptimal linewidth due to the magnetic susceptibility difference between the prostate and air in the rectum or endorectal coil. This can degrade the quality of spectra significantly. The purpose of this study is to evaluate PFC, a compound of carbon and fluorine without hydrogen atoms, to reduce the magnetic susceptibility difference between the air and prostate tissue.

Eight patients with biopsy proven prostate carcinomas were selected. In 3, two MRS examinations were performed once with air and once with PFC in the endorectal coil within 1-16 days. In 5, MRS was performed only with PFC. At the end of MRS, the PFC was removed from the coil and the coil was re-inflated with the air. Linewidth (FWHM) was then re-measured. Approximately 100cc of air and 90cc of PFC were used to fill the coil. The linewidths with air and PFC were compared in all patients. In 3, who had both studies, the MRS results were compared with each other. The spectra were also correlated with biopsy results.

1)The linewidth with PFC (range: 5-10Hz, mean:7.3Hz) was significantly lower (P=0.0001, t-test) than that with air (range: 11-20Hz, mean:16.4Hz). 2)In patients with PFC, the polyamine peak in addition to choline, creatine, and citrate peaks, was resolved clearly in most of normal peripheral zone. 3)Despite significant fat contamination, the spectra with PFC were able to identify each metabolite clearly and tumors more accurately (e.g. choline+creatine/citrate ratio: 0.8-0.9 with air and 1.1–1.2 with PFC in an apical tumor) without losing prostatic tissue within the MRS field.

PFC reduced the spectral linewidth by an average of 9Hz. In all patients whose MR spectra were borderline (>15Hz and/or fat contamination) or unusable for confident interpretation, use of PFC resulted in good to excellent spectral quality (≤10Hz). Filling the endorectal balloon coil with PFC is a highly effective method to improve prostate MRS acquisition.

Choi, H, Zhou, X, Ma, J, Use of Perfluorocarbon (PFC) in Magnetic Resonance Spectroscopy (MRS) of Prostate: A Method to Improve the Linewidth and Quality of Spectra.  Radiological Society of North America 2004 Scientific Assembly and Annual Meeting, November 28 - December 3, 2004 ,Chicago IL. http://archive.rsna.org/2004/4407696.html