Direct comparison of radiology and nuclear medicine cystograms in young infants with vesico-ureteric reflux.

OBJECTIVE

To determine the sensitivity of the direct radionuclide cystogram (DRC) in detecting vesico-ureteric reflux compared with the micturating cysto-urethrogram (MCU) in the same initial setting, in infants younger than one year.

PATIENTS AND METHODS

The results from the dual cystograms of 62 refluxing infants < 1 year old (mean 0.58) were compared. Results from same-day renal scintigraphy with dimercaptosuccinic acid (DMSA) in 60 of the 62 infants were also compared with the reflux grades.

RESULTS

Reflux was detected in 105 units, 96 detected on the DRC and 47 on the MCU, representing a sensitivity of 91% and 45%, respectively. The DRC missed half of grade 1, 20% of grade 2 and 6% of grade 3 reflux. Reflux at low bladder filling rates (DRC) represented 40% of all reflux units, and a half (52%) of scarred renal units detected by DMSA scintigraphy.

CONCLUSIONS

In young infants the MCU may fail to detect significant reflux and the DRC may fail to detect the lesser grades. The combination of both cystograms in the initial investigation of reflux provides more comprehensive information.