Purpose: US is usually considered of little help in studying the ureters because it only shows proximal and distal tracts. The distal ureter is also difficult to study with most of the other imaging methods. Transrectal probes improve depiction of the intramural and pelvic tracts of the ureter, as well as image quality, dramatically providing good results in a short time. The first and, to our knowledge, the only report on this procedure has been Holm's (1994), where the author reported good results though in a small series. For years we have used transrectal US, performed for prostate studies, also to examine intramural ureters and have obtained good results in a short time. Thus we decided to compare the transrectal with the transabdominal approach.
Material and methods: We examined 92 randomly selected male patients with various urologic conditions but no ureter involvement using 3.5 MHz convex and 5.0 MHz biplane transrectal probes. Image quality was rated on an arbitrary scale (0-4) and then submitted to statistical analysis.
Results: Transrectal images were clearly superior to transabdominal ones (p = 0.012) and particularly, ureters were depicted in 93% versus 60% of cases, respectively. The amount of urine in the bladder appears to play a major role (the greater the amount the worse the image quality), while ureter depiction is independent of body habit and bladder squeezing.
Conclusions: Our results are clearly superior to Holm's. Also, considering that the transrectal examination requires a short time, is cost-effective and little invasive, we believe that this method can play an extremely important role in lower ureter studies.