Guang Jia PhD, Presenter: Nothing to Disclose

Ronney Abaza MD, Abstract Co-Author: Nothing to Disclose

Joanna Williams MD, Abstract Co-Author: Nothing to Disclose

Debra Zynger MD, Abstract Co-Author: Nothing to Disclose

Jinyuan Zhou PhD, Abstract Co-Author: Nothing to Disclose

Michael Vinzenz Knopp MD, PhD, Abstract Co-Author: Nothing to Disclose

Wenbo Wei, Abstract Co-Author: Nothing to Disclose

Christina Louise Tosti PhD, Abstract Co-Author: Nothing to Disclose

Zarine Ketul Shah MD, Abstract Co-Author: Nothing to Disclose

Sungkyu Lee MD, Abstract Co-Author: Nothing to Disclose

Steffen Sammet MD, PhD, Abstract Co-Author: Nothing to Disclose

Robert Bahnson MD, Abstract Co-Author: Nothing to Disclose

Prostate cancer typically shows a high tumor cell proliferation rate and cellular density that lead to overall elevated mobile protein and peptide levels, which can be measured by a new molecular imaging technique: Amide-proton-transfer (APT) MRI. This study is to evaluate the capability of APT-MRI for detection and characterization of prostate cancer via mobile protein level mapping.

Twelve patients with biopsy-proven prostate cancer were imaged in a 3 Tesla MRI system (Achieva, Philips Healthcare) using a 32-channel phased array surface coil prior to prostectomy. APT-MRI was based on single-slice single-shot TSE with the following parameters: TR/TE = 6100/56 ms; TSE factor = 47; FOV = 140×140 mm2; Matrix = 80×64; Slice thickness = 6 mm; NSA = 1; acquisition time = 10 minutes. The pre-saturation pulse was composed of a train of sixteen 1800º block pulses with a pulse length of 31 ms. APT ratio (APTR) based on the asymmetric signal at 3.5 ppm of magnetization transfer spectra was defined as the detectable mobile protein levels. Tumor borders were delineated by a pathologist using whole mount pathology slides after prostatectomy.

The mobile protein and peptide levels measured by APTR in the malignant regions were 5.8% ± 3.2%, significantly higher than those in the peripheral zone (PZ) benign regions (0.3% ± 3.2%, P = 0.002). APTR of cancerous ROIs were 4.5% ± 2.1% in T2 stage tumors (N = 7), and 7.7% ± 3.6% in T3 stage tumors (N = 5). Although the difference in mobile protein levels was not significant (P = 0.06), there was a trend of higher mobile protein levels in higher tumor stages. There was also a trend of higher APTR in the PZ tumors (6.5% ± 3.4%, N = 9) than transition zone (TZ) tumors (3.7% ± 1.1%, N = 3; P = 0.06).

APT-MRI can identify an increased level of mobile proteins in regions of the prostate involved with prostate cancer on pathology. The tumor characterization can be revealed by APT-MRI, such as a correlation of the APTR with tumor stages and differentiation between the PZ and TZ tumors.

Amide-proton-transfer MRI has the potential to be a quantitative marker to better delineate and detect malignant regions of the prostate.

Jia, G, Abaza, R, Williams, J, Zynger, D, Zhou, J, Knopp, M, Wei, W, Tosti, C, Shah, Z, Lee, S, Sammet, S, Bahnson, R, Amide Proton Transfer MRI of the Prostate: A Potential Quantitative Method of Mobile Protein and Peptide Levels for Cancer Detection.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9002319.html