A noninvasive test for vesico-ureteric reflux in children

Objective To report the development and testing of a device for the noninva sive diagnosis of vesico-ureteric reflux (VUR) which avoids the need for ur ethral catheterization (currently required to reliably determine the presen ce of VUR). and which thus avoids the anxiety of parents and patients that causes many families to refuse such evaluation, Patients and methods Fifty-four children (49 girls and five boys, mean age 7.2 years, range 4-14) previously evaluated as having VUR volunteered to pa rticipate: no child was symptomatic at the time of the study. Refluxing uni ts were known to be present by voiding cysto-urethrography (within 1 year, mean 7 months) in 45 and absent in 16. The device developed acquires electr onically processed acoustic signals from the child during an observed urina tion. The signals are then analysed 'off-line' to determine the presence or absence of VUR. The initial preparation for the test included: (i) a full bladder [at least 0.80 x {(2 + age) x 30 mL}] measured by ultrasonography: and (ii) localization of the pelvi-ureteric junction by ultrasonography to accurately place the device's sensors on the child's back. The children wer e then positioned at a commode after placing the sensors: the recording was started and continued until voiding occurred. The children were tested wit h the recording and analysis team unaware of the presence and/or degree of VUR. The first 47 studies were single-kidney examinations and the remaining seven included simultaneous monitoring of both kidneys, Results Sixty-one renal units: were assessed and interpretable signals were obtained from 54 (89%). There were seven episodes of 'system failure' when no interpretable data were obtained. One unit with no VUR had a 'reflux' s ignal: in four kidneys, spontaneous (two) and postsurgical (two) resolution of reflux was predicted by the testing and subsequently verified by cyclic radionuclide cystography. Conclusions This noninvasive diagnostic technique detected VUR in 35 of 37 refluxing units and verified no reflux in 16 of 17 units without VUR. Furth er refinements may allow this technology to be used in all children with su spected VUR.