Endoluminal Sonography of the Genitourinary and Gastrointestinal Tracts

Objectives Endoluminal sonography with high‐frequency catheter‐based transducers is a technique well suited to imaging structures beyond the lumen of the hollow viscus. The purpose of this article was to review some aspects of endoluminal sonography, including instrumentation, clinical applications in the gastrointestinal and genitourinary tracts, and its three‐dimensional reconstruction. Methods The development of 6F to 10F catheter‐based ultrasonic probes has made this technique available for use within a variety of lumina. Endoluminal sonography with frequencies of 9 to 20 MHz has been used for evaluation of a wide range of abnormalities in both the genitourinary and gastrointestinal tracts. Results Uses in the gastrointestinal tract include quantification of esophageal varices, distinguishing between various submucosal lesions, and measuring the degree of fibrosis in scleroderma. In the genitourinary system, endoluminal sonography has been used to guide collagen injection, to diagnose urethral diverticula and upper tract neoplasms, to locate crossing vessels and septa for guiding endopyelotomy, and to identify submucosal calculi. Conclusions High‐resolution endoluminal sonography is a new sonographic approach for evaluation of the genitourinary and gastrointestinal tracts. This should lead to the expansion of the diagnostic capabilities of sonography, providing important information for decision making relative to patient care and minimally invasive interventional procedures. Reconstructed three‐dimensional endoluminal sonography has the potential to become a valuable tool in both the research and clinical areas.