Prostate Cancer Diagnosis Improves with MRI Technology

“Oncologists at UC San Diego Moores Cancer Center are the first in San Diego to meld magnetic resonance imaging (MRI) technology with a traditional ultrasound prostate exam to create a three-dimensional map of the prostate that allows physicians to view growths that were previously undetectable.

“An ultrasound machine provides an imperfect view of the prostate, resulting in an under-diagnosis of cancer, said J. Kellogg Parsons, MD, MHS, the UC San Diego Health System urologic oncologist who, along with Christopher Kane, MD, chair of the Department of Urology and Karim Kader, MD, PhD, urologic oncologist, is pioneering the new technology at Moores Cancer Center.

“ ‘With an ultrasound exam, we are typically unable to see the most suspicious areas of the prostate so we end up sampling different parts of the prostate that statistically speaking are more likely to have cancer,’ said Parsons, who is also an associate professor in the Department of Urology at UC San Diego School of Medicine. ‘The MRI is a game-changer. It allows us to target the biopsy needles exactly where we think the cancer is located. It’s more precise.’ ”


MRI Helps Diagnose Prostate Cancer More Accurately

“In a world first, an Australian clinical trial has shown that biopsy guided by MRI can significantly improve the diagnosis of life-threatening prostate cancer and reduce the over-diagnosis of non-life-threatening cases, thus avoiding the side effects of unnecessary treatment.

“At present, to find out if he has prostate cancer – following a test that shows he has raised prostate-specific antigen (PSA) levels – a man has to undergo a painful procedure called transrectal ultrasound guided biopsy (TRUSGB) that involves taking up to 30 random needle biopsies of his prostate through the rectum.”


Metabolic Imaging of Patients with Prostate Cancer Using Hyperpolarized [1-13C]Pyruvate

“This first-in-man imaging study evaluated the safety and feasibility of hyperpolarized [1-13C]pyruvate as an agent for noninvasively characterizing alterations in tumor metabolism for patients with prostate cancer. Imaging living systems with hyperpolarized agents can result in more than 10,000-fold enhancement in signal relative to conventional magnetic resonance (MR) imaging. When combined with the rapid acquisition of in vivo 13C MR data, it is possible to evaluate the distribution of agents such as [1-13C]pyruvate and its metabolic products lactate, alanine, and bicarbonate in a matter of seconds. Preclinical studies in cancer models have detected elevated levels of hyperpolarized [1-13C]lactate in tumor, with the ratio of [1-13C]lactate/[1-13C]pyruvate being increased in high-grade tumors and decreased after successful treatment. Translation of this technology into humans was achieved by modifying the instrument that generates the hyperpolarized agent, constructing specialized radio frequency coils to detect 13C nuclei, and developing new pulse sequences to efficiently capture the signal.”


MRI-Guided Cryoablation Viable for Recurrent Prostate Cancer

“In men with recurrent prostate cancer following radiation therapy, magnetic resonance imaging (MRI)-guided focal cryoablation is feasible and seems safe, according to a study published in the August issue of Radiology. Joyce G.R. Bomers, from Radboud University Nijmegen Medical Centre in the Netherlands, and colleagues, studied 10 consecutive patients with histopathologically proved recurrent prostate cancer after radiation therapy, without evidence of distant metastases. While patients were under general anesthesia, a urethral warmer was inserted, followed by transperineal insertion of cryoneedles during real-time MRI (magnetic resonance imaging) and insertion of a rectal warmer. MRI guidance was used to continuously monitor ice ball growth. Two cycles of freezing and thawing were conducted. Follow-up included a urologist visit, prostate-specific antigen level measurement, and multiparametric MRI at 3, 6, and 12 months.”


Imaging With PET/MR Is More Accurate Than PET/CT For Detecting Recurrent Prostate Cancer

The standard imaging practice for detecting prostate cancer that returns after treatment, called recurrent prostate cancer, combines positron emission tomography (PET) with computed tomography (CT), known as PET/CT. In a recent clinical study researchers from the Technical University Munich in Germany, compared PET/CT to PET combined with magnetic resonance (MR), known as PET/MR. The study involved 31 patients with recurrent prostate cancer and found that PET/MR detected more areas of metastatic tumors, and allowed for more precise mapping of tumors, than PET/CT. The researchers say PET/MR can be considered an alternative to PET/CT, particularly when small tumors are involved. The US FDA approved the first PET/MR device in 2011.


Study Evaluates MRI Versus CT for Detecting Prostate Cancer Recurrence

A recent clinical study compared two different imaging methods for detecting prostate cancer in 31 patients who had disease that returned despite treatment. The imaging systems both use positron emission tomography (PET) combined with either magnetic resonance imaging (MRI) or computed tomography (CT) to detect prostate cancer cells that have spread to different parts of the body. PET combined with MRI (PET/MRI) found more areas of metastatic prostate cancer tumors than PET combined with CT (PET/CT). The lead scientist involved in the study says PET/MRI has higher detection rates and more precisely locates recurrent tumors, which could help doctors tailor specific treatments for patients.