Prostate imaging: evaluation of a reusable two-channel endorectal receiver coil for MR imaging at 1.5 T.
OBJECTIVE
To prospectively compare image quality with use of a two-channel solid reusable phased-array endorectal receiver coil (SPAC) with that of the single-channel inflatable endorectal balloon coil currently in widespread use for 1.5-T magnetic resonance (MR) imaging of the prostate.


METHODS
Institutional review board approval and informed consent were obtained. Multiparametric prostate MR imaging at 1.5 T was performed in patients who were suspected of having cancer. Thirty consecutive patients were included (mean age, 66.1 years; range, 49-76 years). The first 15 patients were imaged by using a balloon coil and an eight-channel external array, and the remaining 15 were imaged with a SPAC alone. One patient was imaged with both techniques. Axial T2-weighted images acquired at both standard and high spatial resolution were used to compare image quality between coils. Qualitative assessments of image quality were made separately by three radiologists. Signal-to-noise ratio (SNR) profiles were determined on a pixel-by-pixel basis in a 1-cm central band in the prostate by using T1-weighted axial images at the apex, midgland, and base. Interrater reliability was determined by using a two-way intraclass correlation coefficient, qualitative scores were compared by using the Student t test for independent samples, and SNR profiles were plotted by using a Biot-Savart curve approximation.


RESULTS
SNR of the SPAC was significantly better compared with that of the balloon coil at distances up to 3.0 cm at the apex and 3.5 cm at the base and midgland (P < .001). There was a 7% improvement in SNR at the mean maximal anteroposterior prostate dimension in this cohort and a 96% improvement at half this distance. At both standard and high spatial resolution, significant improvements in overall image quality (P = .015 and P < .001, respectively), visibility of the anterior gland (P = .009 and P < .001, respectively), and noise (P < .001 and P < .001, respectively) were seen when the SPAC was used. Interrater reliability was 0.536 (95% confidence interval: 0.461, 0.603).


CONCLUSIONS
Both SNR and image quality were significantly improved with use of the SPAC at 1.5 T compared with use of the single-channel inflatable endorectal balloon coil.
From the Department of Medical Imaging, Sunnybrook Health Sciences Centre, University of Toronto, 2075 Bayview Ave, Toronto, ON, Canada M4N 3M5 (M.A.H., M.R.D.R., L.M.); Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Medical Center, Washington, DC (A.K.); and Hologic, Toronto, Ontario, Canada (C.E.).
Masoom A
MA
Haider
Axel
A
Krieger
Christine
C
Elliott
Michael R
MR
Da Rosa
Laurent
L
Milot
D000368:Aged; D004867:Equipment Design; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011471:Prostatic Neoplasms / Q000175:diagnosis*; D015203:Reproducibility of Results; D059629:Signal-To-Noise Ratio