PET/MRI: a one-stop imaging test for detecting prostate cancer

PET/MRI prostate cancer
The figure shows a Gleason 3+4 prostate cancer (arrows) as identified on T2-weighted (A) and diffusion-weighted (B) MRI, F-18-choline PET (C), as well as PET/MRI (D).

In a study newly conducted by the University of Michigan, researchers find that the addition of molecular imaging based on positron emission tomography (PET) can improves the detection of prostate cancer.

The finding is published in The Journal of Nuclear Medicine.

Currently, MRI-guided biopsies already outperform standard, non-targeted biopsies. This study shows that the addition of PET promises to improve targeted biopsies even further.

According to the National Cancer Institute, about 14% of men will be diagnosed with prostate cancer during their lifetime. More than 2.5 million men are estimated to be living with prostate cancer in the U.S.

Since prostate cancer is often multi-focal and presents with multiple lesions of varying risk, it is important to identify the lesions that harbour the greatest malignant potential.

Accurate detection of clinically significant cancer and avoidance of clinically insignificant cancer are the core of modern prostate cancer diagnosis.

In the study, researchers studied 36 men with rising prostate-specific antigen to assess the value PET/MRI for image-guided prostate biopsies to detect significant prostate cancer.

The result showed that 15 subjects were ultimately identified with significant prostate cancer, of which PET/MRI image-guided biopsy identified 12, while standard biopsy identified only 5.

Researchers suggest that PET/MRI may become a one-stop imaging test for men with suspected but undetected prostate cancer or for patients undergoing surveillance for known low-risk prostate cancer.

The use of advanced imaging to inform placement of biopsy can greatly minimize the uncertainty associated with prostate cancer care.

Imaging may one day be performed prior to biopsy and, if negative, no biopsy would be needed.

To reach that future state, advanced imaging will need to have a superior negative predictive value that may not be obtainable with multi-parametric MRI alone.

Although researchers used F-18-choline PET in this study, it is likely that other radiotracers that are more specific for prostate cancer may hold even greater promise.

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Citation: Piert M, et al. (2016). 18F-Choline PET/MRI: The Additional Value of PET for MRI-Guided Transrectal Prostate Biopsies. The Journal of Nuclear Medicine, 57: 1065-1070. DOI: 10.2967/jnumed.115.170878.
Figure legend: This image is credited to University of Michigan.