Objective: To compare endorectal coil (ERC) and pelvic phased array (PPA) coil magnetic resonance imaging for delineation of the prostate gland and seminal vesicles. To compare ERC images at different inflation volumes of the ERC air balloon.
Materials and methods: Twenty-one patients underwent T2-weighted examinations using PPA and ERC. The ERC evaluations were performed at three balloon inflation volumes (60, 100 and 140 ml). All patients had proven prostate cancer. Images were analysed for visibility of anatomic structures, gland distortion, tumour visualization, artefacts (coil flare, coil-related artefact and rectal movement) and overall image quality. A grading system was used for each parameter.
Results: ERC assessments at increasing balloon inflations showed equivalent anatomical detail and overall image quality. However, increasing gland distortion and decreasing coil related flare was found with higher air inflations (P = 0.13 and P = 0.006, respectively). When compared with ERC images, visibility of the anterior gland and neurovascular bundles was better with the PPA coil (P = 0.0001 and 0.002, respectively). The overall image quality was superior with the PPA coil (P = 0.0001). However, no significant difference in visualization of tumour or delineation of tumour extent was observed between the two techniques.
Conclusions: PPA imaging of the prostate gland provides images of superior quality compared with the ERC. This is mainly due to fewer artefacts with the PPA coil and improved anterior gland visibility. When ERC is used, air inflation to at least 100 ml reduces coil flare artefact.