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
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