AJR:174, June 2000 1575 Initial Experience with Contrast-Enhanced Sonography of the Prostate OBJECTIVE. We investigated the usefulness of contrast-enhanced sonography to depict vascularity in the prostate and improve the detection of prostatic cancer. SUBJECTS AND METHODS. Twenty-six patients with an elevated prostate-specific antigen level (≥ 4 ng/ml) or an abnormal digital rectal examination were enrolled in a phase II study of an IV injected sonographic contrast agent. Continuous gray-scale, intermittent gray- scale, phase inversion gray-scale, and power Doppler sonography of the prostate were per- formed. Sonographic findings were correlated with sextant biopsy results. RESULTS. After the administration of contrast material, gray-scale and Doppler images revealed visible enhancement ( p < 0.05). Using intermittent imaging, we found focal en- hancement in two isoechoic tumors that were not visible on baseline images. No definite focal area of enhancement was identified in any patient without cancer. Contrast-enhanced images revealed transient hemorrhage in the biopsy tracts of three patients. CONCLUSION. Enhancement of the prostate can be seen on gray-scale and Doppler sonographic images after the administration of an IV contrast agent. Contrast-enhanced intermittent sonography of the prostate may be useful for the selective enhancement of malignant prostatic tissue. n 1999, approximately 179,300 American men developed pros- tatic cancer [1]. Because approxi- mately one third of patients sent for biopsy have cancer, we estimate that over 500,000 prostate biopsies are performed annually in the United States. Although most clinicians use sonography to guide needle placement for prostate biopsy, a recent review of the prostate sonography literature suggests that imaging has little advantage for the detection of malignant lesions [2]. Our own evaluation of gray-scale, color, and power Doppler sonography reveals that these techniques are minimally superior to chance in the detection of prostatic cancer [3]. An accurate noninva- sive imaging study of prostatic cancer would allow limited targeted biopsy of suspicious sites and might reduce the number of pa- tients subjected to biopsy of the prostate. Increased microvessel density in prostatic cancer is reported to correlate with the pres- ence of metastases [4], the stage of disease [5– 7], and disease-specific survival [8, 9]. In other words, microvessel density in prostatic cancer is predictive of clinically significant disease. Microbubble-based sonographic contrast agents may reveal prostatic cancer based on in- creased microvascularity. Although color Dop- pler enhancement of the prostate has been reported with contrast agents [10, 11], no pub- lished study has revealed gray-scale parenchy- mal enhancement of the prostate. We used intermittent gray-scale imaging to evaluate contrast-enhanced imaging of the prostate and to selectively enhance the neovasculature asso- ciated with prostatic cancer. Subjects and Methods Twenty-six patients with prior abnormal digital rectal exams or elevated (≥4 ng/ml) prostate-specific antigen levels were recruited for a phase II study of the contrast agent Imagent (AF0150; Alliance Phar- maceutical, San Diego, CA). Eligible patients were 18–80 years old and scheduled for transrectal sonog- raphy of the prostate with biopsy. Patient age ranged from 38 to 81 years (mean age, 64 years). The study included 18 Caucasians, six African-Americans, one Hispanic, and one Indian. The institutional review board approved this study, and written informed consent was obtained from each patient. Study participants were prepared according to standard operating procedure for patients undergoing Ethan J. Halpern 1 Lev Verkh 2 Flemming Forsberg 1 Leonard G. Gomella 3 Robert F. Mattrey 4 Barry B. Goldberg 1 Received August 18, 1999; accepted after revision November 3, 1999. Supported in part by Alliance Pharmaceutical Corporation. 1 Department of Radiology, Jefferson Prostate Center, Thomas Jefferson University, 132 S. 10th St., Philadelphia, PA 19107-5244. Address correspondence to E. J. Halpern. 2 Alliance Pharmaceutical Corp., 3040 Science Park Rd., San Diego, CA 92121. 3 Department of Urology, Jefferson Prostate Center, Thomas Jefferson University, Philadelphia, PA 19107-5244. 4 Department of Radiology, University of California at San Diego, 200 N. Arbor Dr., San Diego, CA 92103. AJR 2000;174:1575–1580 0361–803X/00/1746–1575 © American Roentgen Ray Society I Downloaded from www.ajronline.org by 52.73.204.196 on 05/16/22 from IP address 52.73.204.196. Copyright ARRS. For personal use only; all rights reserved