Detection of urolithiasis: comparison of 100% tube exposure images reconstructed with filtered back projection and 50% tube exposure images reconstructed with sinogram-affirmed iterative reconstruction.

PURPOSE: To compare images acquired with 50% tube exposure with a dual-source computed tomographic (CT) scanner and reconstructed with sinogram-affirmed iterative reconstruction (SAFIRE) with 100% exposure images reconstructed with filtered back projection (FBP) for reader ability to detect stones, reader confidence, and findings outside the urinary tract. MATERIALS AND METHODS: In this HIPAA-compliant, institutional review board-approved study, imaging examinations in 99 patients with urolithiasis were assessed. Data from both tubes were reconstructed with FBP; data from the primary tube only were reconstructed with SAFIRE. Seven readers evaluated randomized studies for calculi in nine regions. Reader confidence was scored by using a five-point scale. Ancillary findings were noted. Nonparametric methods for clustered data were used to estimate the area under the receiver operating characteristic curves with 95% confidence intervals to test for noninferiority of 50% exposure with SAFIRE. RESULTS: Calculi were found in 113 locations (pyelocalyceal ureter, 86; proximal ureter, seven; midureter, four; distal ureter, 15; bladder, one) and not found in 752 locations. Mean area under the receiver operating characteristic curve for FBP was 0.879 (range, 0.607-0.967) and for SAFIRE, 0.883 (range, 0.646-0.971; 95% confidence interval: -0.025, 0.031). The SAFIRE images were not significantly inferior to FBP images (P = .001). Reader confidence levels for images with stones were similar with FBP and SAFIRE (P = .963). For the 52 patients who had extraurinary findings, readers reported them correctly in 74.4% (271 of 364) and 72.0% (262 of 364) of cases (P = .215) for FBP and SAFIRE, respectively. For the nine patients with potentially important findings per the reference standard, the detection rates were 44% (28 of 63) and 33% (21 of 63, P = .024), respectively. For the 43 patients with unimportant or likely unimportant findings, the false detection rates were 15% (44 of 301) and 14% (43 of 301, P = .756), respectively. CONCLUSION: The 50% tube exposure CT images reconstructed with SAFIRE were not inferior to 100% exposure images reconstructed with FBP for diagnosis of urolithiasis, without decreases in reader confidence.

Imaging evaluation of laparoscopic greater curvature plication: preliminary observations.

OBJECTIVE: The purpose of this article is to assess normal imaging findings and complications after laparoscopic greater curvature plication on luminal upper gastrointestinal studies and CT. MATERIALS AND METHODS: This was a retrospective chart review of 24 adults who underwent laparoscopic greater curvature plication between 2008 and 2011. Seventeen patients (70.8%) underwent postoperative luminal upper gastrointestinal studies, and four (16.7%) underwent postoperative CT. Normal imaging features and complications were recorded. The percentage of intraluminal gastric diameter occupied by the plicated segment and the percentage of greater curvature involved on postoperative upper gastrointestinal luminal studies were determined. RESULTS: A multilobular intraluminal filling defect reflecting the surgical plication occupied the proximal third of the greater curvature in 16 of 17 patients (94%), extending to the mid portion in 10 of 17 patients (59%) and to the distal third in one of 17 patients (6%). There was luminal narrowing of 50-75% in 14 of 17 patients (82%) and narrowing of 25-50% in two patients (12%). In 14 of 17 patients (82%), the plication involved 50-75% of the greater curvature length and 25-50% in the remaining three patients (18%). In four patients who underwent CT, a central low-attenuation stripe accompanied the plication. Five of 24 patients (21%) had complications, including extraluminal gastric leak (n = 1), gastric outlet obstruction (n = 2), and plication suture failure (n = 2). CONCLUSION: Laparoscopic greater curvature plication is seen as multilobular filling defects most commonly along the proximal greater curvature with 50-75% narrowing of the gastric lumen. A linear low-attenuation stripe accompanies the filling defect on CT.