ULTRASONIC DIAGNOSIS FOR URINARY TRACT

Mainly For Determination of Staging of Bladder Tumor

Abstract

Assessment of infiltration in bladder tumors is important in both deciding management of the particular case and developing its prognosis. Various techniques have been attempted to determine the extent of infiltration, most highly regarded being pelvic arteriography which is 80-90% accurate according to literatures.
In 1975, McLaughlin et al., measured the degree of bladder tumor infiltration by means of ultrasound tomography scanning via the abdominal wall and reported that the findings were comparable to those of pelvic arteriography. The present authors used ultrasound via the abdominal wall in the diagnosis of 48 patients with bladder tumor. The findings were related to the excised bladder and new criteria for estimation of the extent of infiltration were derived. The results were then compared with those of other methods.
Method and Criteria: A multi-purpose ultrasonic diagnostic apparatus, ALOKA SSD 60B with a concave transducer of 13φ-80mm of curvature diameter was used in this experiment. The bladder was filled with 200-300ml of physiological saline solution and the recording made through the abdominal wall by sector scanning.
Criteria for the estimation of extent of bladder tumor infiltration by ultrasound: U-I: Echoes from the tumor are detectable, but disappear at different gain, while echoes from the bladder wall are well recorded. U-II: Echoes from the tumor are detectable. When gain is changed, however, echoes from the tumor disappear and echoes from the bladder wall partly vanish. U-III: Echoes from the tumor are detectable. When gain is changed, however, echoes both from the tumor and the bladder wall completely vanish at the same time.
U-I therefore corresponds to T₁, U-II to T₂, and U-III to T₃ or T₄. The above-mentioned criteria were established on the basis of the findings in 8 cases of total cystectomy in which all of the specimens were examined by the dipping method, and related to the histopathologic findings.
Results: T₁: 31 cases (3 failed cases; 3 cases diagnosed as U-II) Accuracy is 90%. T₂: 5 cases (1 case diagnosed as U-III) Accuracy is 80%. T_3-4: 9 cases (1 case diagnosed as U-II) Accuracy is 89%
Diagnosis impossible: 3 cases. Two of the three patients with T₁ had tumor spreading from the anterior wall to the apex and a clear echo image was not obtained due to interference from the pubic bone. The other, although it was of noninfiltrating type, was erroneously diagnosed as U-II because of surface calcification which resulted in a loss of part of the bladder wall echo because the muscle layer was invaded by tumor. In one patient with T₂, over-diagnosis as U-III was made because the tumor was so large that echoes from the bladder wall could not be recorded. All other 40 cases showed good correlation between TNM classification and ultrasonic assessment.
Examination of the excised bladder by the dipping method showed that echoes from bladder tumor are weaker and disappear sooner than echoes from bladder wall. Namely, when the tumor does not infiltrate into the muscle layer, echoes from the tumor are lost while ultrasonic beams emmited at different gains are still well echoed from the bladder wall. When the muscle layer is damaged by infiltration of tumor, however, echoes from both the tumor and the bladder wall are lost at the same time. Irregularity and deformation of the bladder wall, which are taken into account for diagnosis by McLaughlin et al., were different from individual to individual, without correlation to infiltration of tumor in our study.