A new MRI technique has demonstrated potential for correcting distortion in prostate cancer imaging, offering a better look at tumor position that could improve treatment planning.
Results of a pilot study involving the technique, called restriction spectrum imaging MRI (RSI-MRI), were published online in Prostate Cancer and Prostatic Disease.
“Current imaging of prostate cancer is done with contrast-enhanced MRI,” senior author Anders Dale, PhD, professor of radiology at the University of California, San Diego, said in a press release. “Unfortunately, some tumors fail to show a marked difference from surrounding healthy tissue due to lack of uptake of the contrast agent.”
Current prostate MRI techniques have demonstrated variable sensitivity ranging from 49-88 percent. Standard diffusion-weighted imaging (DWI) can help, according to the authors, but it suffers from distortion due to magnetic field inhomogeneity and relatively high false-positive rates.
Dale and colleagues developed RSI-MRI to help improve prostate cancer MRI and limit magnetic field artifacts. “By collecting a broader, more extended spectrum of diffusion images, combined with sophisticated modeling of differential water compartments in tissue and correction of spatial distortion, RSI-MRI theoretically focuses on the signal emanating from the intracellular water compartment of tumor cells and thereby minimizes false-positive signals,” the authors wrote.
For the pilot study, Dale and colleagues evaluate 27 patients, nine of whom with histologically proven pT3 prostate cancer, or extraprostatic extension. RSI-MRI was able to identify extraprostatic extension in eight of those patients, compared with only two of nine patients being identified using standard MRI. RSI-MRI also correctly identified more confined pT2 disease in the remaining 18 patients.
Based on the initial findings, the authors called for further testing in a larger group of patients.
“Presurgical MRI results may provide additional information for clinicians and patients by informing surgical planning (that is, nerve sparing). Other potential applications for RSI-MRI meriting further study include lesion localization for targeting of image-guided biopsies, serial imaging in an active surveillance population and evaluation of posttreatment recurrence following primary radiotherapy,” wrote Dale and colleagues.
The study was funded by the National Institute of Biomedical Imaging and Bioengineering.