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The "free" routine postcatheterization urogram: a cost/benefit analysis
Insights
Routine postangiography urography in children provides low clinical yield and significant radiation exposure. Modifying the procedure reduces average abdominal radiation dose by over 87%.
Area of Science:
- Pediatric Cardiology
- Diagnostic Imaging
- Radiation Oncology
Background:
- Postangiography urography is a common procedure following cardiac catheterization in pediatric patients.
- Concerns exist regarding the diagnostic yield and radiation exposure associated with this routine practice.
Purpose of the Study:
- To analyze the x-radiation dosage and clinical significance of routine postangiography urography in children.
- To evaluate the necessity of routine postangiography cine-urography in pediatric cardiac patients.
Main Methods:
- Radiation exposure to the abdomen and gonads was measured using lithium fluoride thermoluminescent dosimeters in 35 children.
- Clinical significance of 334 consecutive routine postangiography cine-urograms was retrospectively evaluated.
- Radiation doses from cine-urography, fluoroscopy, and abdominal roentgenograms were quantified.
Main Results:
- Average abdominal radiation dose was 241 mR from cine-urography, 16 mR from fluoroscopy, and 107 mR from a single roentgenogram.
- Gonadal dosage averaged 8 mR, consistently below 27 mR.
- Only 3% of routine cine-urograms revealed clinically significant urologic conditions; 9% were technically inadequate.
Conclusions:
- Routine postangiography cine-urography in children offers a low yield of clinically significant findings and contributes substantial radiation exposure.
- A revised protocol involving fluoroscopic examination of renal collecting systems, with selective abdominal roentgenograms, significantly reduces radiation dose.
- This modified approach lowers the mean average absorbed abdominal radiation dose from 241 mR to 30.5 mR.
Abstract:
Postangiography urography has become routine procedure in most centers performing cardiac catheterization in children. We analyzed the x-radiation dosage and clinical yield of this procedure. Using lithium fluoride thermoluminescent dosimeters, radiation exposure to the abdomen and gonads was measured in 35 children during postangiography urography. Results of 334 consecutive routine postangiography cine-urograms were evaluated based on clinical significance and compared to previous reports on this subject. Average absorbed abdominal radiation dosage was 241 mR +/- 240 from cine-urography, 16 mR +/- 13 from fluoroscopy, and 107 mR +/- 111 from a single abdominal roentgenogram. Gonadal dosage averaged 8 mR and was uniformly less than 27 mR. Of 334 routine postangiography cineurograms, 282 (84%) were normal, 30 (9%) were technically inadequate, 12 (3%) had abnormalities that were clinically insignificant or were falsely "positive" and in 10 (3%), clinically significant urologic conditions were confirmed. Because of the low yield of clinically significant anomalies and the added radiation exposure, we no longer perform routine postangiography cine-urography in children. Following cardiac angiography, the upper renal collecting systems are examined fluoroscopically. If abnormalities are suspected or fluoroscopy is equivocal, a single abdominal roentgenogram is performed. Using this procedure, mean average absorbed abdominal radiation dose can be reduced from 241 mR to 30.5 mR.