Grading of reflux by radionuclide cystography

: Over a three-year period, radionuclide cystography (RC) was performed on 145 patients. Of these, 31 nephroureteral units in 25 patients demonstrated vesicoureteral reflux by RC and also by radiographic cystography (XC). The RC and XC studies were performed within three months of one another. The grading of reflux was determined by RC and then compared with that of XC using the criteria for grading as established by the International Reflux Study Committee (IRSC). Of 18 nephroureteral units in 14 patients with grade II reflux by XC, 14 were similarly graded by RC (78%). Of five nephroureteral units in five patients with grade III reflux by XC, the correlation by RC was 100%. However, when grades II and III were combined into a single category of low-grade reflux, the correlation achieved between the two cystographic techniques was 100%. Of five nephroureteral units in four patients with grade IV reflux by XC, the correlation was 60%, and in three units in two patients with grade V reflux the correlation was 100%. When grades IV and V are combined into a category of high-grade reflux, a correlation of 100% is achieved. When the reflux is graded into the five IRSC categories, the overall unequivocal correlation between the two studies is 80%. However, when only two categories are used (low grade = grades II and III, and high grade = grades IV and V), a correlation of 100% is obtained.