TY - JOUR
T1 - Detectability of urinary stones on virtual nonenhanced images generated at pyelographic-phase dual-energy CT
AU - Takahashi, Naoki
AU - Vrtiska, Terri J.
AU - Kawashima, Akira
AU - Hartman, Robert P.
AU - Primak, Andrew N.
AU - Fletcher, Joel G.
AU - McCollough, Cynthia H.
PY - 2010/7
Y1 - 2010/7
N2 - 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 non-enhanced 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 pyelographicphase dual-energy CT enabled the detection of urinary stones with moderate accuracy. The detection of small (1-2-mm) stones was limited.
AB - 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 non-enhanced 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 pyelographicphase dual-energy CT enabled the detection of urinary stones with moderate accuracy. The detection of small (1-2-mm) stones was limited.
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U2 - 10.1148/radiol.10091411
DO - 10.1148/radiol.10091411
M3 - Article
C2 - 20574095
AN - SCOPUS:77953950382
SN - 0033-8419
VL - 256
SP - 184
EP - 190
JO - Radiology
JF - Radiology
IS - 1
ER -