Gauging the Effectiveness of 3T Multiparametric MRI — with and without an Endorectal Coil — in Prostate Cancer Detection

By Nick Klenske

Because prostate cancer is a complex condition encompassing a broad range of disease and numerous stages, using imaging to detect and manage the disease is extremely difficult.

Mirak

Multi-parametric MRI (mpMRI), an emerging form of functional imaging, has gained importance in the detection and characterization of prostate cancer, which remains the most common malignancy among American men.

While mpMRI has proven effective for detecting significant prostate cancer lesions, the imaging tool is limited in the detection of smaller cancer foci. One possible way to remedy this shortcoming is to pair an endorectal coil (ERC) with the mpMRI, according to presenters of a Tuesday session.

"Small lesions require improved images with even higher magnetic fields, which is where the use of an endorectal coil could apply," said presenter Sohrab Afshari Mirak, MD, with the UCLA Prostate Imaging Research Group, during a session on Tuesday.

Dr. Mirak presented the findings of a UCLA study comparing prostate cancer detection using mpMRI with and without ERC with whole mount histopathology (WMHP). Conducted from June 2009 to December 2016, the study comprised 429 prostate cancer patients who underwent 3T mpMRI prior to robotic prostatectomy.

In total, 871 consecutive WMHP localized lesions were included. The authors examined 260 patients with 529 lesions with ERC and 169 patients with 342 lesions without ERC. The two groups were then compared based on overall and index lesions, tumor location and size, Gleason Score (GS) and staging.

"What we found was that the overall and index tumor detection rates were slightly – but not significantly – higher for the ERC group," Dr. Mirak said.

The overall detection rate for the ERC study group was 50.3 percent, compared to 48.2 percent for the non-ERC group. No significant difference was found when considering tumor size, level, GS or staging.

"We did, however, achieve a significantly higher detection rate for posterior and peripheral prostate cancer lesions when using ERC," Dr. Mirak said. "But for anterior and transition prostate lesions, the opposite is true, with detection rates being significantly higher in the non-ERC group."

Dr. Mirak notes that there were limits to the study. For example, it was retrospective and utilized a single referral institute, excluded patients with treatments other than prostatectomy and did not pair the ERC and non-ERC groups.

Despite these limitations, Dr. Mirak believes the study's findings are of importance. "This study shows that when it comes to detecting prostate cancer lesions, there are particular advantages to using 3T mpMRI with and without an endorectal coil," he said. "For this reason, depending on the individual patient, we utilize both methods at UCLA."