MRI-guided ultrasound more sensitive than TRUS for targeted prostate biopsy

A study presented at the
recent European Association of Urology 13th Central European meeting showed
that Magnetic Resonance Imaging-Ultrasound (MRIUS)- guided prostate biopsy has
high sensitivity to detect prostate abnormalities compared with transrectal
ultrasonography (TRUS biopsy) of MRI positive findings. 

“The systematic 12-core
transrectal ultrasound guided biopsy (TRUS biopsy) which is currently
considered the standard of care for the diagnosis of prostate cancer (PCa),
misses many small, non-palpable and ultrasound invisible lesions,” said
presenting author Anna Katarzyna Czech of the Dept. of Urology, Jagiellonian
University in Krakow, Poland. Although new imaging modalities, including MRI,
have improved the rate of tissue abnormality detection, Czech said these
procedures are time-consuming and uncomfortable for a patient, so limiting
their use. 

“However, by fusing MRI with TRUS images it became possible for the
urologist to perform the MRI-guided TRUS biopsies in the office setting,” she
added. In their study, Czech and colleagues used the real-time fusion of TRUS
images with previously recorded MR images (MRIUS), based on linear
interpolation of pixels. Eighty men, who had prostate lesions detected
exclusively in the transrectal prostate magnetic resonance imaging, were
included in the study. All men were randomized into two groups (40 patients
each) and underwent TRUS guided biopsy. 

In group I, TRUS biopsies of
MRI-identified lesions were performed, while in group II biopsies of the
lesions visualized in MRI were performed using MRIUS method which allowed for
the real-time fusion of TRUS images with the previously recorded MR images. The
researchers found that MRIUS guided prostate biopsy yielded respectively 22.5%,
10% and 7.5% more prostate cancer, atypical small acinar proliferation (ASAP)
and the high-grade prostatic intraepithelial neoplasia (HGPIN) and chronic
prostatitis cases, compared with TRUS biopsies of the MRI identified lesions.
The sensitivity to identify microscopically confirmed prostate abnormalities
was 40% with TRUS guided prostate biopsy of MRI-identified lesions and 80% with
MRIUS method. 

“Fusion technology guided biopsy yielded 42.5% more prostate
abnormalities than the TRUS biopsy of MRI-positive lesions. Moreover,
MRIUS-targeted biopsies were sufficient in all PCa cases to determine their
clinical significance, making the fusion technology a potential solution for
the patients with clinical suspicion of prostate cancer,” explained Czech. She
also noted that the use of 3Tesla MRI for fusion technology, which would
eliminate use of endorectal coil, needs to be investigated. Despite these
limitations the authors pointed out that MRIUS guided prostate biopsy has high
sensitivity to detect prostate abnormalities. “It markedly improved ability to
detect clinically significant lesions compared with TRUS biopsy of MRI positive
findings,” they said.