Document Detail


Detectability of urinary stones on virtual nonenhanced images generated at pyelographic-phase dual-energy CT.
MedLine Citation:
PMID:  20574095     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
PURPOSE: To evaluate the detectability of urinary stones on virtual nonenhanced images generated at pyelographic-phase dual-energy computed tomography (CT). MATERIALS AND METHODS: This retrospective HIPAA-compliant study was institutional review board approved. All included patients had previously consented to the use of their medical records for research. Sixty-two patients (38 men, 24 women; age range, 35-91 years) had undergone CT urography, which consisted of nonenhanced and pyelographic-phase dual-energy CT performed by using a dual-source scanner. Commercial software was used to create virtual nonenhanced images by suppressing the iodine signal from the pyelographic-phase dual-energy CT scans. Two radiologists, in consensus, evaluated the virtual nonenhanced images for the presence of stones. Sensitivity for detecting stones was calculated on a per-stone basis. Sensitivity, specificity, and accuracy were also calculated on a per-renal unit (defined as the intrarenal collecting system and ureter of one kidney) basis. The true nonenhanced scan was considered the reference standard. A jackknife method was used because any patient may have multiple stones. RESULTS: Of 62 patients with 122 renal units, 21 patients with 25 renal units had a total of 43 stones (maximal transverse diameter range, 1-24 mm; median, 3 mm). The overall sensitivity for detecting stones was 63% (27 of 43 stones) per stone. Sensitivities were 29% (four of 14 stones) for 1-2-mm stones, 64% (nine of 14 stones) for 3-4-mm stones, 83% (five of six stones) for 5-6-mm stones, and 100% (nine of nine stones) for 7-mm or larger (7, 7, 7, 8, 8, 9, 11, 15, and 24 mm) stones. All three ureteral stones (3, 4, and 8 mm) were correctly identified. The sensitivity, specificity, and accuracy for detecting stones on a per-renal unit basis were 65% (17 of 26 renal units), 92% (88 of 96 renal units), and 86% (105 of 122 renal units), respectively. CONCLUSION: Virtual nonenhanced images generated at pyelographic-phase dual-energy CT enabled the detection of urinary stones with moderate accuracy. The detection of small (1-2-mm) stones was limited.
Authors:
Naoki Takahashi; Terri J Vrtiska; Akira Kawashima; Robert P Hartman; Andrew N Primak; Joel G Fletcher; Cynthia H McCollough
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Radiology     Volume:  256     ISSN:  1527-1315     ISO Abbreviation:  Radiology     Publication Date:  2010 Jul 
Date Detail:
Created Date:  2010-06-24     Completed Date:  2010-07-16     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0401260     Medline TA:  Radiology     Country:  United States    
Other Details:
Languages:  eng     Pagination:  184-90     Citation Subset:  AIM; IM    
Affiliation:
Department of Radiology, Mayo Clinic, Rochester, MN 55905, USA.
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MeSH Terms
Descriptor/Qualifier:
Adult
Aged
Aged, 80 and over
Confidence Intervals
Contrast Media / diagnostic use
Female
Humans
Iohexol / diagnostic use
Male
Middle Aged
Radiographic Image Interpretation, Computer-Assisted
Radiography, Dual-Energy Scanned Projection / methods
Retrospective Studies
Sensitivity and Specificity
Software
Subtraction Technique
Tomography, X-Ray Computed / methods*
Urinary Calculi / radiography*
Urography
Chemical
Reg. No./Substance:
0/Contrast Media; 66108-95-0/Iohexol

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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