Abstract
It is generally held that computed tomography (CT) is useful in diagnosing acquired renal cyst in long-term dialysis patients, as well as renal cancer, which very often follows as a complication. Few cases in which ultrasonography (US) works for that purpose have been reported. But we believe that US is highly useful in diagnosing renal cancer and renal cyst and have been using the technique as the first alternative to conventional X-ray examination.
We performed US on 94 long-term dialysis patients for the screening of renal cancer and renal cyst and compared the results with those from CT. Our findings are as follows.
With US, most kidneys (96.8%; with the exception of very contracted kidneys) were successfully pictured. Renal cysts were better diagnosed by US than by CT. With US and CT together, multiple cysts were diagnosed in 44.2% of all patients and solitary cyst was noted as a complication in 11.6%. The longer dialysis had been performed, the higher the cyst complication rate was: 41.4% when dialysis was performed for less than 2 years; 48.1% for 2-4 years; 66.6% for 4-6 years; 83.4% for 6 years and longer. With US, two cases of renal cancer were diagnosed, but one of them could not be diagnosed with CT. CT provided a better diagnosis of calcification, most of which could not be diagnosed by US. Three cases of intracystic hemorrhage diagnosed by US and US-guided puncture.
Besides renal lesions, US also provided successful diagnosis of 11 cases of cholelithiasis and 4 cases of liver cysts, hepatomegaly and splenomegaly, 2 cases of pleural effusion and 1 case of ascites, some cases of dilatation of the hepatic vein and inferior vena cava.
Considering the above results and the ease, noninvasiveness, economy of US, we believe that US should come first in diagnosing abdominal disease, including renal cyst and cancer in dialysis patients. We also believe that regular abdominal ultrasonography preformed on patients with chronic renal disease even before dialysis is started will be effective in gaining an overall understanding of chronic renal failure.
