A clinical comparison of rigid and inflatable endorectal-coil probes for MRI and 3D MR spectroscopic imaging (MRSI) of the prostate.
OBJECTIVE
To compare the data quality and ease of use of four endorectal-coil probe setups for prostate MRI.


METHODS
Four endorectal-coil probe setups were compared: 1) air-inflated probe; 2) perfluorocarbon (PFC)-inflated probe; 3) rigid, smaller prototype coil; and 4) rigid, smaller coil designed for biopsying the prostate. Signal-to-noise ratio (SNR), positioning, shimming, MRI motion artifact, and MR spectroscopic imaging (MRSI) spectral quality were assessed.


RESULTS
Rigid coils provided approximately 2.5-fold higher SNR than inflatable coils near the peripheral zone midline. The biopsy probe sensitivity decreased dramatically by the apex. The rigid probes, as compared to the inflatable probes, took longer to place (10 +/- 2 vs. 7 +/- 2 minutes, P < 0.0002), tended to be placed too superiorly, required repositioning more often (73% vs. 20%, P < 0.003), and had higher motion artifacts (P < 0.001). Shimming time was least for the PFC-inflated probe (2 +/- 0.5 minutes, P < 0.05). The air-inflated probe produced larger linewidths (P < 0.01) and tended to have longer shim times (7 +/- 4 minutes) and poorer spectral quality.


CONCLUSIONS
The inflatable coil is a good clinical choice due to ease of use, good coverage, and low motion artifacts. PFC-inflation is recommended as it provided higher quality data than air-inflation. The rigid, smaller probes have higher SNR and produce less tissue distortion and may be preferred for certain applications.
Noworolski
Susan M
SM
Department of Radiology, University of California, San Francisco, San Francisco, California 94107, USA. sue@radiology.ucsf.edu
Crane
Jason C
JC
Vigneron
Daniel B
DB
Kurhanewicz
John
J
D016477:Artifacts; D001706:Biopsy / Q000295:instrumentation; D016009:Chi-Square Distribution; D005466:Fluorocarbons; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D009682:Magnetic Resonance Spectroscopy / Q000295:instrumentation*; D008297:Male; D019047:Phantoms, Imaging; D011471:Prostatic Neoplasms / Q000473:pathology*; D012007:Rectum; D012680:Sensitivity and Specificity
D005466:Fluorocarbons