Contrast specific imaging in the detection and localization of prostate cancer

Abstract

Prostate cancer (PCa) is the most common cancer in elderly men and is one of the most important causes of death from cancer in men. The diagnosis of PCa is based on a combination of digital rectal examination, PSA and transrectal ultrasound (TRUS). However, this combination does not reach the accuracy of detection and localization necessary for proper decisions on treatment methods. Therefore, biopsies are performed in all cases for which the suspicion of PCa is raised. Even with biopsies, staging and grading of PCa is far from optimal. More accurate imaging is necessary to improve the biopsy sampling, the goals being to replace systematic biopsies by a targeted approach and to improve staging and grading of PCa. Ultrasound imaging of the prostate remains the first choice of imaging to visualize the prostate, however, gray-scale ultrasound imaging has an accuracy of about 50-60% for the detection of PCa and TRUS used for local staging has an even lower accuracy. The development of PCa is associated with changes in the metabolism of tumor cells, and therefore with changes in the blood perfusion of the involved tissue. This paper focuses on contrast specific imaging techniques to visualize these changes in blood perfusion. Techniques such as color and power Doppler imaging, and contrast enhanced imaging techniques using color and power Doppler, harmonic imaging and intermittent imaging are discussed.

Optoacoustic characterization of prostate cancer in anin vivotransgenic murine model

“…4 However, the accuracy of this technique is reported to be less than 50% to 60% with respect to the detection of prostate cancer, due largely to the weak contrast at depth in soft tissues. [5][6][7] Conventional diagnosis is currently based solely on the detection of gross anatomic properties of tissues. Recent techniques have been developed that probe tissue microstructure based on the spectral analysis of radio frequency (RF) data; 8,9 however, these ultrasonic techniques do not provide any information on the oxygen saturation or hemoglobin concentration of the tissue, both of which are often altered with neoplasia.…”

Coherence-based contrast ultrasound diffusion imaging for prostate cancer detection

“…Several methods have aimed at detection of angiogenesis by quantitative transrectal ultrasound (TRUS) imaging of tissue perfusion, i.e., blood flow per tissue volume [3]. These methods use ultrasound contrast agents (UCAs) to detect microvascular flow [3], [6]. UCAs are dispersions of gas microbubbles that backscatter acoustic energy when invested by ultrasound waves [7].…”

“…Angiogenesis correlates to cancer aggressiveness and is required for cancer to grow beyond 1 mm 3 [5]. Several methods have aimed at detection of angiogenesis by quantitative transrectal ultrasound (TRUS) imaging of tissue perfusion, i.e., blood flow per tissue volume [3]. These methods use ultrasound contrast agents (UCAs) to detect microvascular flow [3], [6].…”

“…A biopsy investigation commonly involves taking 6 to 12 geometrically distributed tissue samples from the prostate with a hollow needle [3]. In retrospective, only 24% of the patients undergoing biopsy investigations are diagnosed with prostate cancer [4].…”

“…Currently, prostate cancer diagnosis is based on one or more systematic biopsy investigations, which are performed if the suspect of prostate cancer is raised by noninvasive methods such as the PSA blood test [3], [4]. A biopsy investigation commonly involves taking 6 to 12 geometrically distributed tissue samples from the prostate with a hollow needle [3].…”