Combined magnetic resonance urography and targeted helical CT in patients with renal colic: A new approach to reduce delivered dose
✍ Scribed by Alfredo Blandino; Fabio Minutoli; Emanuele Scribano; Sergio Vinci; Carlo Magno; Stefano Pergolizzi; Nicola Settineri; Ignazio Pandolfo; Michele Gaeta
- Publisher
- John Wiley and Sons
- Year
- 2004
- Tongue
- English
- Weight
- 522 KB
- Volume
- 20
- Category
- Article
- ISSN
- 1053-1807
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✦ Synopsis
Purpose:
To determine whether magnetic resonance urography (mru), obtained before helical computed tomography (ct) in patients with acute renal colic, can help delimit the obstructed area to be subsequently examined by a targeted ct scan, thus reducing the dose of radiation.
Materials and methods:
Patients (51) with symptoms of acute renal colic underwent mru and a total urinary tract helical ct. ct images from the 5 cm below the level of ureteral obstruction as demonstrated by mru were selected out. combined interpretation of mru and selected ct images constituted protocol a. protocol b consisted of the entire unenhanced helical ct of the urinary tract. the two protocols were compared regarding the following points: 1) sensitivity in diagnosing the presence of obstructing urinary stones, and 2) the delivered radiation dose.
Results:
Protocol a and protocol b had, respectively, 98% and 100% sensitivity in demonstrating ureteral stone as a cause of renal colic. estimated average dose calculated from phantom study was 0.52 msv for protocol a and 2.83 msv for protocol b. therefore, the effective radiation dose was 5.4 times lower in protocol a compared to protocol b.
Conclusion:
Combined mru and short helical ct has a high sensitivity in detecting ureteral calculi with a reduced radiation dose.