Faculty Bibliography

Congenital abnormalities of the pericardium are a rare group of disorders that include congenital absence of the pericardium, pericardial cysts, and diverticula. These congenital defects result from alterations in the embryologic formation and structure of the pericardium. Although many cases are incidentally found, they can present as symptomatic, life-threatening disease. Owing to their rarity, many cases are inappropriately diagnosed. Alterations in the embryologic formation and structure may result in the formation of these congenital abnormalities. We review the presentation, diagnosis, and management of congenital absence of the pericardium, pericardial cysts, and diverticula. A summary of multimodality imaging features is provided.

BACKGROUND: The presence of calcified plaque in coronary arteries can be quantified by using 0.5-mm isotropic reconstructions from 320-row CT without increased radiation dose. Little is known about reclassification of patients with non-zero Agatston scores and quantitative measures of calcified plaque using 0.5-mm reconstructions. OBJECTIVE: The aim was to compare proportions of zero vs. non-zero Agatston scores (subclinical atherosclerosis) in 0.5-mm isotropic reconstructions vs. standard 3.0-mm and CT angiography (CTA) scans on 320-row CT. METHODS: Prospectively, we quantified calcified plaque in coronary arteries in 104 patients by using non-contrast-enhanced scans with 0.5 and 3.0 mm. Coronary calcium assessment was determined by 2 observers. Clinically indicated CTA was also performed; coronary calcium assessment findings were compared with CTA. Ranked Wilcoxon test and chi2 test were performed for comparison. Reproducibility for proportion of zero vs non-zero was assessed by kappa statistics. RESULTS: Median Agatston score (41.9 [interquartile range (IQR), 3.7-213.6] vs. 5.2 [IQR, 0.0-128.5]), calcium volume (53.6 mm3 [IQR, 8.1-202.3] vs. 5.1 mm(3) [IQR, 0.0-96.8],), and lesion number (10.0 [IQR, 3.5-18.5] vs. 1.0 [IQR, 0.0-6.0]) were significantly higher on 0.5-mm reconstruction (P < .0001) than on 3.0-mm reconstruction. More patients with subclinical atherosclerosis were detected on 0.5 mm than on 3.0 mm and CTA scans (76.9% vs. 53.8% vs. 54.8%; P < .0001). The kappa values for inter-rater agreement were 0.94 and 0.52 on 3.0- and 0.5-mm data sets, respectively. However, when Agatston scores < 10 were excluded from analysis, the kappa value rose to 0.83. CONCLUSION: Isotropic 0.5-mm reconstruction detected 23.1% and 22.1% more patients with subclinical atherosclerosis than standard 3.0-mm scans and CTA, which may be more sensitive for the detection of subclinical atherosclerosis; its potential clinical utility needs to be validated in large, prospective studies.

OBJECTIVES: This study was designed to assess the effects on resource utilization of routine coronary computed tomographic angiography (CCTA) in triaging chest pain patients in the emergency department (ED). BACKGROUND: The routine use of CCTA for ED evaluation of chest pain is feasible and safe. METHODS: We conducted a retrospective multivariate analysis of data from two risk-matched cohorts of 894 ED patients presenting with chest pain to assess the impact of CCTA versus standard evaluation on admissions rate, length of stay, major adverse cardiovascular event rates, recidivism rates, and downstream resource utilization. RESULTS: The overall admission rate was lower with CCTA (14% vs. 40%; p < 0.001). Standard evaluation was associated with a 5.5-fold greater risk for admission (odds ratio [OR]: 5.53; p < 0.001). Expected ED length of stay with standard evaluation was about 1.6 times longer (OR: 1.55; p < 0.001). There were no differences in the rates of death and acute myocardial infarction within 30 days of the index visit between the two groups. The likelihood of returning to the ED within 30 days for recurrent chest pain was 5 times greater with standard evaluation (OR: 5.06; p = 0.022). Standard evaluation was associated with a 7-fold greater likelihood of invasive coronary angiography without revascularization (OR: 7.17; p < 0.001), while neither group was significantly more likely to receive revascularization (OR: 2.06; p = 0.193). The median radiation dose with CCTA was 5.88 mSv (n = 1039; confidence interval: 5.2 to 6.4). CONCLUSIONS: The routine use of CCTA in ED evaluation of chest pain reduces healthcare resource utilization.

Coronary computed tomography angiography (CCTA) is increasingly used for the assessment of coronary heart disease (CHD) in symptomatic patients. Software applications have recently been developed to facilitate efficient and accurate analysis of CCTA. This study aims to evaluate the clinical application of computer-aided diagnosis (CAD) software for the detection of significant coronary stenosis on CCTA in populations with low (8%), moderate (13%), and high (27%) CHD prevalence. A total of 341 consecutive patients underwent 64-slice CCTA at 3 clinical sites in the United States. CAD software performed automatic detection of significant coronary lesions (>50% stenosis). CAD results were then compared to the consensus manual interpretation of 2 imaging experts. Data analysis was conducted for each patient and segment. The CAD had 100% sensitivity per patient across all 3 clinical sites. Specificity in the low, moderate, and high CHD prevalence populations was 64%, 41%, and 38%, respectively. The negative predictive value at the 3 clinical sites was 100%. The positive predictive value was 22%, 21%, and 38% for the low, moderate, and high CHD prevalence populations, respectively. This study demonstrates the utility of CAD software in 3 distinct clinical settings. In a low-prevalence population, such as seen in the emergency department, CAD can be used as a Computer-Aided Simple Triage tool to assist in diagnostic delineation of acute chest pain. In a higher prevalence population, CAD software is useful as an adjunct for both the experienced and inexperienced reader.

OBJECTIVE: We describe our preliminary experience with coronary computed tomography angiography (CCTA) in emergency department (ED) patients with low- to intermediate-risk chest pain. METHODS: A convenience cohort of patients with low- to intermediate-risk acute chest pain presenting to a suburban ED in 2009 were prospectively enrolled if the attending physician ordered a CCTA for possible coronary artery disease. Demographic and clinician data were entered into structured data collection sheets required before any imaging. The results of CCTA were classified as normal, nonobstructive (1%-50% stenosis), and obstructive (>50% stenosis). Outcomes included hospital admission and death within a 6-month follow-up period. RESULTS: In 2009, 507 patients with ED chest pain had a CCTA while in the ED. The median (interquartile range) age was 54 (47-62) years; 51.5% were female. Thrombolysis in myocardial infarction risk scores were 0 (42.6%), 1 (42.2%), 2 (11.8%), 3 (2.4%), and 4 (1.0%). The results of CCTA were normal (n = 363), nonobstructive (n = 123), and obstructive (n = 21). Admission rates by CCTA results were obstructive (90.5%), nonobstructive (4.9%), and normal (3.0%). None of the patients with normal or nonobstructive CCTA died within the 6-month follow-up period (0%; 95% confidence interval, 0-0.9%). CONCLUSIONS: Many ED patients with low- to intermediate-risk chest pain have a normal or nonobstructive CCTA and may be safely discharged from the ED without any associated mortality within the following 6 months.