To investigate incidental extra-cardiac findings (ECF) at cardiac CT based on indication and impact on patient management. We retrospectively reviewed the reports of 1,764 patients who underwent a cardiac CT study between January 1, 2004 and December 31, 2006, including 463 calcium scorings (CS), 737 coronary CT angiograms (CTA), 341 pulmonary vein stenoses (PVS), and 223 bypass grafts (CABG). ECFs were categorized by type of examination, anatomical location and clinical significance. Comparisons were made between examination types to determine if incidental findings varied by indication. There were 507 ECFs with at least one ECF in 441 patients (25.0%). By examination, there was at least 1 ECF in 79/463 CS studies (17.1%), 196/737 CTAs (26.6%), 80/341 PVSs (23.4%) and 86/223 CABGs (38.6%). In 325 patients (18.4%), the findings were considered clinically important and occurred in 60/463 (12.9%) CSs, 149/737 (20.2%) CTAs, 56/341 (16.4%) PVSs and 60/223 (26.9%) CABGs. Differences between CABG and other indications and CTA vs. CS for incidental and clinically important findings were statistically significant (p < 0.05). Extra-cardiac findings requiring follow-up occur in 18% of patients and are significantly more frequent in coronary artery CTA and coronary artery bypass studies than in calcium scoring studies.

During the use of a single lot of custom breakpoint panels (Sensititre; Radiometer America Inc., Westlake, Ohio), imipenem susceptibility declined from 70 to 44% for clinical isolates of Pseudomonas aeruginosa. With a new lot, susceptibility increased to 73%. Subsequent evaluations with P. aeruginosa ATCC 27853 revealed a similar susceptibility pattern and an increase in the MIC of imipenem when determined in panels with increasing ages. Imipenem concentrations were determined by high-performance liquid chromatography by using 11 different lots of MIC and breakpoint panels (139 to 893 days of age). The amount of imipenem remaining declined from 94.4 to 13.8% (r = 0.9225) over the age range of the panels. These data suggest that imipenem in Sensititre MIC and breakpoint panels degrades over time and that the decrease in imipenem may be largely responsible for the decline in P. aeruginosa susceptibility.