CHICAGO--Although ultrasound has been the primary imaging technique used in the assessment of the prostate gland for potential malignancy, it has been secondary to PSA assays and the digital rectal examination as a screening technique because "the cost-benefit ratio is too low to warrant its use," Matthew D. Rifkin, MD, said at the annual meeting of the Radiological Society of North America. New technological refinements of sonographic equipment, however, may allow a bigger role for ultrasound in prostate cancer in the future, said Dr. Rifkin, chair of the Department of Radiology, Albany Medical College, NY.
With 3D ultrasound, radiologists can manipulate images in order to obtain greater visualization of a prostate lesion and its relationship to the seminal vessels, neurovascular bundle, and other important regional structures, information that may guide the treatment approach.
"Three-dimensional ultrasound can have major implications with our urologic colleagues on how they may treat patients," Dr. Rifkin said, "because it allows us to look at where the lesion is, how much nerve-sparing can be done or how much of the prostate has to be taken out, how the apex or potentially the base is involved, and where the seminal vesicle is located."
Prostate cancer, like many other malignancies, grows faster than normal tissue and benign hyperplasia. It therefore has an increased supply of nutrients and blood flow, he said. Color Doppler, by revealing increased flow to a region within the prostate, can identify lesions that are not palpable and are otherwise invisible so they may be subjected to ultrasound-guided biopsy.
Contrast agents currently in clinical trials can enhance the conspicuity of blood flow, particularly abnormal flow, and likewise identify a lesion that is not palpable in an isoechoic area.
Dr. Rifkin believes these developments have enormous potential not only for increasing the accuracy of detecting prostate cancer but also for helping urologists and surgeons find the most appropriate avenue of care.
"With contrast agents, 3D, and color Doppler, we may have much better visualization--better than magnetic resonance imaging and computed tomog-raphy--of the vascular supply to the prostate and any infiltration by tumor," he said, "which may change the plan for surgical or nonsurgical intervention."