Prostate cancer is the most common cancer in men with an estimate of 218,890 new cases in 2007 in the U.S. alone, according to the National Cancer Institute (NCI). Due to its prevalence in the male population, as well as its unpredictable clinical course, early detection and diagnosis have become a priority for many health care professionals. Screening tests for early detection of this disease are crucial in order to decrease morbidity and mortality; they include digital rectal examination (DRE), transrectal ultrasound (TRUS) and serum prostate specific antigen (PSA). Serum PSA is the most common screening test for prostate cancer, offering high sensitivity but low specificity for cancer detection. Other indices have been developed in an effort to improve the overall specificity. However, the benefit of these examinations remains controversial. An abnormal or suspicious screening test (PSA level > 4ng/ml, or abnormal DRE examination) is usually followed by an ultrasound-guided transrectal biopsy, which is considered the gold standard for presurgical diagnosis and classification of prostate cancer.

The initial aspect of prostate cancer staging is accomplished clinically using DRE, which is sensitive to tumors in the lateral and posterior aspects of the peripheral zone. Another method for staging prostate cancer is through imaging techniques, which include ultrasound, computed tomography (CT), and MRI with or without the help of dynamic contrast enhancement modeling (DCE-MR), diffusion-weighted imaging (DWI), and multidimensional MR Spectroscopy (MRS).

The proposed IDEA project includes a novel four-dimensional MRS technique using a state-of-the-art 3T MRI scanner. An external multi-coil array will be used for acquisition, thus eliminating the need for an endorectal coil. This novel acquisition will significantly minimize patient discomfort, which was unavoidable with earlier approaches using the endorectal coil.

Another major goal of this work is to quantify the tissue metabolites in prostate cancer in vivo using a novel quantitation method to process the acquired multi-dimensional MRS data. Recent reports using ex-vivo prostate tissue specimens have demonstrated the feasibility of detecting more than 20 chemicals or metabolites and lipids using a high field MRS spectrometer. These studies shed more light into the role of omega-3 and omega-6 fatty acids and the relationship between food intake and prostate cancer. For example, polyunsaturated fatty acids (PUFA) have been detected using these ex-vivo measurements. The proposed study, on the other hand, will be fully noninvasive, enabling quantitation of several metabolites including PUFA. A list of in vivo concentrations of different metabolites in prostate tissues will be produced out of every MRI/MRS examination that is similar to laboratory test results from the blood specimens and biological fluids. A major outcome of this project will be to enable an improved biochemical assay to discriminate malignant from benign prostate lesions. This opens a new avenue for identifying the metabolic profiles of prostate tumors with more exact anatomical localization using spectral data from the entire prostate that characterize tissue metabolism.

Successful completion of the proposed project will lead to better understanding and therapeutic management of prostate cancer and also serve as a basis for better biochemical characterization of cancers in other organs, namely brain, breast, pancreas, etc.