3T MR of the prostate: Reducing susceptibility gradients by inflating the endorectal coil with a barium sulfate suspension

Abstract

Most prostate MRI/MRS examinations are performed with an endorectal coil inflated with air, leading to an air-tissue interface that induces magnetic susceptibility gradients within the gland. Inflation of the coil with a barium sulfate suspension is described and compared to inflation with air or liquid perfluorocarbon (PFC). The B 0 field in the prostate gland was mapped for five healthy volunteers when the endorectal coil was inflated with each of the three agents. A marked decrease in the posterior-anterior (P-A) field gradient and a significant improvement in field homogeneity were evident in the presence of a barium suspension and PFC relative to air. MRS data acquired from the prostate gland in the presence of air, PFC, and a barium suspension in the endorectal coil showed similar trends, demonstrating improvement in line-widths and spectral resolution when the barium suspension or the PFC were inflating the endorectal coil. On this basis we conclude that a barium suspension provides an available, cheap, and safe alternative to PFC, and we suggest that inflating the endorectal coil with a barium suspension should be considered for prostate MR studies, especially at high field strengths (such as 3T). Magn Reson Med 57:898 -904, 2007.

Automated Computer-derived Prostate Volumes from MR Imaging Data: Comparison with Radiologist-derived MR Imaging and Pathologic Specimen Volumes

“…Ninety-one prostates were analyzed with MR images acquired with a 3-T wholebody imager (GE Healthcare Technologies, Waukesha, Wis) and an endorectal coil (Medrad, Pittsburgh, Pa) infl ated with 60 mL of a 100% weight per volume barium sulfate suspension for improved spatial resolution (27)(28)(29) …”

Local staging of prostate cancer with MRI

“…Filling the endorectal coil with a perfluorocarbon (PFC) compound has been shown to improve the diagnostic quality of MRS (15). Inflating the endorectal coil with a barium suspension may be an alternative to inflation with PFC in prostate MR studies, especially at high field strengths (such as 3 T) (16).…”

Practical aspects of prostate MRI: hardware and software considerations, protocols, and patient preparation

“…After insertion into the rectum, the balloon is inflated, with 40-80 ml of either an inert fluid that matches the susceptibility of the prostatic tissues, e.g., perfluorocarbon (PFC) or barium sulfate [31], or alternatively with air or water. Using an inert fluid instead of air or water improves the homogeneity of the magnetic field and decreases susceptibility artifacts between the rectum and the prostate [32,33]. These inflatable ERCs provide better coverage, are associated with fewer motion artifacts, and are faster to position when compared to rigid coils [31].…”