Prostate MRI: Access to and Current Practice of Prostate MRI in the United States

Abstract

Purpose-Magnetic resonance imaging (MRI) of the prostate has increasingly become more important in clinical medicine due to the risk of over-detection of low-grade, low-volume prostate cancer as well as due to the poor sampling of transrectal ultrasound-guided prostate biopsy in high-risk patients. We sought to determine the access, imaging protocols, and indications for MRI imaging of the prostate in the United States. Materials and Methods-A brief survey was sent through mailing lists to members of the Society of Abdominal Radiology and Texas Radiological Society.Results-Thirty-six academic centers responded to the survey, 88.9% of which routinely perform prostate MRI. Nine centers routinely performed imaging at 1.5T with an endorectal coil (25%), 11 performed at 3.0T without an endorectal coil (31%), and 10 performed at 3.0T with an endorectal coil (28%). All institutions used T1-weighted axial and orthogonal T2-weighted sequences. Most groups used diffusion weighted imaging (94.7%) and dynamic contrast enhancement (81.6%). Only 21.1% of groups performing prostate MRI routinely performed magnetic resonance spectroscopy as part of their protocol.Conclusions-Prostate MRI is becoming a commonly performed examination at academic institutions, with most locations performing prostate MRI at minimum standards. There is a need to educate non-academic practices regarding the addition of functional MRI techniques to anatomic techniques, increase the number of institutions that regularly perform prostate MRI, and increase access to direct MRI-guided biopsy in institutions that perform prostate MRI on a regular basis.

MRI of the Prostate in Germany: Online Survey among Radiologists

“…One recent mono-institutional prospective randomized controlled trial demonstrates that combined T2WI, MRS, and DCE with subsequent targeted and systematic randomized biopsies under transrectal ultrasonography (TRUS) guidance significantly improves prostate cancer detection when compared with TRUS-guided, systematic randomized biopsies alone in patients with one previous negative prostate biopsy and PSA serum levels of 4.0 -10.0 ng/ml [16]. DCE-MRI was the second most frequently applied functional MR method in prostate imaging both at 1.5 T and 3.0 T in this survey, similar to a recent survey among US-American academic centers [11]. Although being equally applied at 1.5 T between HDs and PPs and between participants performing more or less than 50 prostate MR examinations in 2011, DCE at 3.0 T was more often applied in HDs than in PPs.…”

“…Among participants of this survey who performed MR examinations of the prostate in 2011, all applied T2WI. A recent survey among members of the Society of Abdominal Radiology and Texas Radiological Society affiliated with academic centers came to the same result [11]. All of the functional MR imaging methods, including MRS, DWI, and DCE, were applied at both 1.5 T and 3.0 T among the participants of this survey, if at different proportions.…”

“…MRS, as the oldest and bestvalidated functional MR method for prostate examinations at the time of the survey, also was the one least frequently used among participants of this survey. However, it was more frequently applied in Germany, at both 1.5 T and 3.0 T, than in a recent survey among academic centers in the US [11]. MRS was applied more often at 3.0 T than at 1.5 T, and in HDs rather than in PPs.…”

“…DWI, in turn, was the most frequently applied functional MR method in prostate examinations performed at both 1.5 T and 3.0 T, with no significant differences between HDs and PPs, and between participants with higher and lower workloads than 50 cases in 2011, and showed the smallest difference between users of 1.5 T and 3.0 T technology. Similarly, a recent survey among academic centers in the US showed that 95 % applied DWI in MR examinations of the prostate [11]. Reasons may include that DWI provides images that are immediately available, without additional post-processing, that the scientific concept of demonstrating the decrease in free motion of water molecules within tissue that is due to increased cellular volume and decreased inter-cellular interstitial space has been known for a long time from MRI of the brain, that required software is essentially available on most modern MR scanners, and that DWI takes little additional scan time and no additional patient preparation.…”

“…More than 90 % of the participants of this survey applied 1.5 T MR scanners for prostate imaging, either exclusively or alternately to 3.0 T platforms. In turn, less than 30 % of participants offered MR examinations of the prostate at 3.0 T. Thus, in contrast to trends in current original research on MR examinations of the prostate and patterns of use among members of the Society of Abdominal Radiology and Texas Radiological Society affiliated with academic centers [11], 1.5 T technology still represented the mainstay of prostate MR imaging in Germany in 2011. However, in contrast to current German guideline recommendations [4], more than 75 % of those participants who performed MR examinations of the prostate at 1.5 T used surface coils, but no ERCs.…”