|Low dose CT protocal for kidney stones|
| Posted: Tue Apr 24th, 2012 01:06 pm
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What is your CT protocal for f/u kidney stones using a low dose technique??? Thank you for your time.
| Posted: Wed Apr 25th, 2012 02:16 am
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|depending on the scanner you can scan with 80 or 100kVp and this will drop dose but still see stones. here is a recent reference
J Urol. 2011 Mar;185(3):910-4. Epub 2011 Jan 15.
Low dose computerized tomography for detection of urolithiasis--its effectiveness in the setting of the urology clinic.
Zilberman DE, Tsivian M, Lipkin ME, Ferrandino MN, Frush DP, Paulson EK, Preminger GM.
Comprehensive Kidney Stone Center, Division of Urologic Surgery, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27710, USA. firstname.lastname@example.org
Low dose noncontrast computerized tomography is becoming a common imaging tool to diagnose urolithiasis. We investigated its usefulness as a diagnostic tool in the outpatient setting.
MATERIALS AND METHODS:
A total of 62 patients with suspected urolithiasis underwent standard renal stone protocol computerized tomography with a tube current of 160 mA. Images were modified by adding image noise to simulate tube currents of 70, 100 and 130 mA. Three urologists independently interpreted the original and simulated dose scans for stone number, location and associated signs of obstruction. In addition, the investigators rated the ease of interpreting the scans and their overall level of confidence.
There were no statistically significant differences in interobserver and intra-observer variability for stone detection or obstruction signs except significant interobserver variability in hydronephrosis and intra-observer variability in stranding categories. Each 1 mm increase in stone size increased the likelihood of a concordant response 3.55, 2.7 and 2-fold when reducing the tube current level by 19%, 38% and 56%, respectively (p=0.001, 0.008 and 0.021, respectively). Multiple stones or index stone location were not associated with agreement. The overall level of confidence decreased with lower simulated doses, particularly in the bony pelvis (p<0.02).
Low dose computerized tomography may serve as an effective tool in the setting of the urology clinic in patients with urolithiasis. This imaging tool can better assess urolithiasis and associated obstruction than plain abdominal radiographs, but it may be problematic with small stones (less than 2 mm) and evidence of distal ureteral obstruction. Its effectiveness as a long-term followup tool requires further prospective trials.
Copyright Â© 2011 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.
| Posted: Wed Apr 25th, 2012 02:26 am
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