PURPOSE: To compare ADC values measured from diffusion-weighted MR (DW-MR) images of the prostate obtained with both endorectal and phased-array coils (ERC+PAC) to those from DW-MRI images obtained with an eight-channel torso phased-array coil (PAC) at 3.0T.
METHODS: The institutional review board issued a waiver of informed consent for this HIPAA-compliant study. Twenty-five patients with biopsy-proven prostate cancer underwent standard 3-T MRI using 2 different coil arrangements (ERC+PAC and PAC only) in the same session. DW-MRI at five b-values (0, 600, 1000, 1200, and 1500s/mm2) were acquired using both coil arrangements. On b=0 images, signal-to-noise ratios (SNRs) were measured as the ratio of the mean signal from PZ and TZ ROIs to the standard deviation from the mean signal in an artifact-free ROI in the rectum. Matching regions-of-interest (ROIs) were identified in the peripheral zone and transition zone on ERC-MRI and PAC-MRI. For each ROI, mean ADC values for all zero and non-zero b-value combinations were computed.
RESULTS: Mean SNR with ERC-MRI at PZ (66.33±27.07) and TZ (32.69±12.52) was 9.27 and 5.52 times higher than with PAC-MRI ((7.32±2.30) and (6.13±1.56), respectively) (P< 0.0001 for both). ADCs from DW-MR images obtained with all b-values in the PZ and TZ were significantly lower with PAC-MRI than with ERC-MRI (P< 0.001 for all).
CONCLUSION: Lower SNR of DW-MR images of the prostate obtained with a PAC can significantly decrease ADC values at higher b-values compared to similar measurements obtained using the ERC. To address these requirements, clinical MR systems should have image processing capabilities which incorporate the noise distribution.
Written by:
Mazaheri Y, Vargas HA, Nyman G, Shukla-Dave A, Akin O, Hricak H. Are you the author?
Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY, United States; Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY, United States.
Reference: Eur J Radiol. 2013 Jun 27. pii: S0720-048X(13)00265-9.
doi: 10.1016/j.ejrad.2013.04.041
PubMed Abstract
PMID: 23810189
UroToday.com Prostate Cancer Section
