MR-guided biopsies at 3T are showing great promise in prostate cancer because of their speed and high tumor detection rate in patients with rising PSA levels and previous negative biopsies, according to a leading research team from the Netherlands. They also do well in patients who have had previous radiotherapy sessions.
In an electronic poster presentation, Dr. Thomas Hambrock and his fellow radiologists from the St. Radboud University Medical Center in Nijmegen, explained why these procedures are viable and easy to perform. They use a 32-channel phased-array coil and prototype biopsy device, and are claiming impressive results.
With the patient in the prone position, the practitioner inserts a gadolinium needle guider endorectally, along with a 3D positioning device, and takes axial and sagittal T2-weighted TSE images. The 35-minute examination is well tolerated, the investigators noted.
Conversely, there is an increasing rationale for performing prostate interventions in the supine position, Dr. Gregory Bootsma and colleagues from Princess Margaret Hospital in Toronto wrote in another electronic poster. Conventional systems have good biopsy-needle targeting accuracy, but require that the patient lie in a prone or left lateral decubitus position, which compromises stability, comfort, and safety. The Canadian group favors a dedicated table that docks to the diagnostic MR unit, integrates imaging coils, and creates perineal access. Their custom-built interventional table comes from Sentinelle Medical in Toronto, and they have adapted the company's Aegis software.
"Recent studies have shown that prostate motion is reduced when patients are placed in the supine position," they stated.
Overall, MR-guided prostate interventions provide excellent soft tissue contrast and resolution, and enable assessment of adjacent tissues at risk of injury, the burden of disease within the gland, and the biological profile of the disease, Bootsma said. They provide the ability to characterize pathology and biology through dynamic contrast-enhanced, MR spectroscopic, and diffusion-weighted imaging.
