Rationale, design, and goals of the Advanced Cardiovascular Imaging Consortium (ACIC): A Blue Cross Blue Shield of Michigan collaborative quality improvement project.

BACKGROUND: Coronary computed tomography angiography (CCTA) is an emerging noninvasive anatomical method for evaluation of patients with suspected coronary artery disease (CAD). Multicenter clinical registries are key to efforts to establish the role of CCTA in CAD diagnosis and management. The Advanced Cardiovascular Imaging Consortium (ACIC) is a statewide, multicenter collaborative quality initiative with the intent to establish quality and appropriate use of CCTA in Michigan. METHODS: The ACIC is sponsored by the Blue Cross Blue Shield of Michigan/Blue Care Network, and its 47 sites include imaging centers that offer CCTA and meet established structure and process standards for participation. Patients enrolled include those with suspected ischemia with or without known CAD, and individuals across the entire spectrum of CAD risk. Patient demographics, history, CCTA scan-related data and findings, and 90-day follow-up data are entered prospectively into a centralized database with strict validation tools and processes. Collaborative quality initiatives include radiation dose reduction and appropriate CCTA use by education and feedback to participating sites and referring physicians. CONCLUSIONS: Across a wide range of institutions, the ACIC permits evaluation of "real-world" utilization and effectiveness of CCTA and examines an alternative, nontraditional approach to utilization management wherein physicians and payers collaborate to address the growing problem of cardiac imaging overutilization.

Late endovascular aneurysm repair infection presenting with juxatrenal aortic rupture treated with in situ aortic replacement.

Infection of an endovascular abdominal aneurysm repair (EVAR) is rare but has become more prevalent with the standardization of EVAR for treating infrarenal abdominal aortic aneurysms. The understanding of this complex aortic condition has improved but still remains to evolve. We present a patient with an EVAR infection manifesting with juxtarenal aortic rupture as a result of a urinary tract infection. This report describes an unusual presentation of an EVAR infection treated with in situ aortic reconstruction and provides >1 year of follow-up.

Asymmetric septal hypertrophic cardiomyopathy: a case report.

We report the case of a 30-year-old female who presented to the emergency department with the chief complaint of syncope. She also described intermittent chest pain and exertional dyspnea over the past several weeks. Review of systems and laboratory findings including D: -dimer levels were noncontributory. EKG demonstrated right bundle branch block. Nongated chest CT with contrast was ordered to exclude the possibility of pulmonary embolism demonstrating markedly asymmetric septal thickening. Suspicion for hypertrophic cardiomyopathy was raised, which was subsequently confirmed on gated cardiac MRI.

Impact of a continuous quality improvement initiative on appropriate use of coronary computed tomography angiography. Results from a multicenter, statewide registry, the Advanced Cardiovascular Imaging Consortium.

OBJECTIVES: The purpose of the study was to determine the effectiveness of a collaborative educational, continuous quality improvement (CQI) initiative to increase appropriate use of coronary computed tomography angiography (CCTA). BACKGROUND: Potential overuse of CCTA has prompted multisociety appropriate use criteria (AUC) publications. METHODS: This prospective, observational study was conducted with pre-intervention (July 2007 to June 2008), intervention (July 2008 to June 2010), and follow-up (July 2010 to December 2010) periods during which patients were enrolled in the Advanced Cardiovascular Imaging Consortium (ACIC) at 47 Michigan hospitals. Continuous education was provided to referring physicians. The possibility of losing third-party payer coverage in the absence of a measurable change in AUC was emphasized. AUC was compared between the 3 periods. RESULTS: The study group included 25,387 patients. Compared with the pre-intervention period, there was a 23.4% increase in appropriate (61.3% to 80%, p < 0.0001), 60.3% decrease in inappropriate (14.6% to 5.8%, p < 0.0001), 40.8% decrease in uncertain (10.3% to 6.1%, p < 0.0001), and 41.7% decrease in unclassifiable (13.9% to 8.1%, p < 0.0001) scans during follow-up. Between pre-intervention and follow-up, change in CCTA referrals by provider specialty were cardiology (appropriate: 60.4% to 79.5%; inappropriate: 13% to 5.2%; p < 0.0001), internal medicine/family practice (appropriate: 51.1% to 70.4%; inappropriate: 20.2% to 12.5%; p < 0.0001), emergency medicine (appropriate: 83.6% to 91.6%; inappropriate: 9.1% to 0.6%; p < 0.0001), and other (appropriate: 61.1% to 83.2%; inappropriate: 18.6% to 5.9%; p < 0.0001). CONCLUSIONS: Application of a systematic CQI and emphasis on possible loss of coverage were associated with a significant improvement in the proportion of CCTA examinations meeting AUC across referring physician specialties.

Coronary computed tomography angiography in dialysis patients undergoing pre-renal transplantation cardiac risk stratification.

BACKGROUND: This study addresses the safety, feasibility, and interpretability of coronary computed tomography angiography (CCTA) in excluding significant coronary artery disease in end-stage renal disease patients on dialysis undergoing pre-renal transplant cardiac risk evaluation. METHODS: Twenty nine patients (55.5 +/- 10.2 years) undergoing cardiac risk assessment prior to renal transplantation, underwent research CCTA with calcium scoring and formed the study group. All CCTAs were performed using retrospective acquisition, with beta-blockade provided one hour prior to scanning. RESULTS: No major complications occurred in this group up to 30 days after CCTA. Of the total of 374 segments interpreted by both readers, only 36 (10%) were uninterpretable by both readers. Of these, 31 (86%) were from distal segments or branches. On a segmental level, there was 95% concordance between both readers for < 50% stenosis detection. Only three out of 28 (11%) CCTAs were deemed uninterpretable. Ten patients (36%) had zero calcium score, despite being on dialysis with no evidence of obstructive coronary artery disease by CCTA. CONCLUSIONS: CCTA is feasible and safe in end-stage renal disease dialysis patients with the advent of 64-slice CCTA. Despite significant calcium burden, there was excellent inter-observer agreement at segment level for the left main and all three proximal-mid coronary arteries in excluding obstructive coronary artery disease (> 50% stenosis).

Computer-aided diagnosis of lung nodules on CT scans: ROC study of its effect on radiologists' performance.

RATIONALE AND OBJECTIVES: The aim of this study was to evaluate the effect of computer-aided diagnosis (CAD) on radiologists' estimates of the likelihood of malignancy of lung nodules on computed tomographic (CT) imaging. METHODS AND MATERIALS: A total of 256 lung nodules (124 malignant, 132 benign) were retrospectively collected from the thoracic CT scans of 152 patients. An automated CAD system was developed to characterize and provide malignancy ratings for lung nodules on CT volumetric images. An observer study was conducted using receiver-operating characteristic analysis to evaluate the effect of CAD on radiologists' characterization of lung nodules. Six fellowship-trained thoracic radiologists served as readers. The readers rated the likelihood of malignancy on a scale of 0% to 100% and recommended appropriate action first without CAD and then with CAD. The observer ratings were analyzed using the Dorfman-Berbaum-Metz multireader, multicase method. RESULTS: The CAD system achieved a test area under the receiver-operating characteristic curve (A(z)) of 0.857 +/- 0.023 using the perimeter, two nodule radii measures, two texture features, and two gradient field features. All six radiologists obtained improved performance with CAD. The average A(z) of the radiologists improved significantly (P < .01) from 0.833 (range, 0.817-0.847) to 0.853 (range, 0.834-0.887). CONCLUSION: CAD has the potential to increase radiologists' accuracy in assessing the likelihood of malignancy of lung nodules on CT imaging.

Effect of CAD on radiologists' detection of lung nodules on thoracic CT scans: analysis of an observer performance study by nodule size.

RATIONALE AND OBJECTIVES: To retrospectively investigate the effect of a computer-aided detection (CAD) system on radiologists' performance for detecting small pulmonary nodules in computed tomography (CT) examinations, with a panel of expert radiologists serving as the reference standard. MATERIALS AND METHODS: Institutional review board approval was obtained. Our dataset contained 52 CT examinations collected by the Lung Image Database Consortium, and 33 from our institution. All CTs were read by multiple expert thoracic radiologists to identify the reference standard for detection. Six other thoracic radiologists read the CT examinations first without and then with CAD. Performance was evaluated using free-response receiver operating characteristics (FROC) and the jackknife FROC analysis methods (JAFROC) for nodules above different diameter thresholds. RESULTS: A total of 241 nodules, ranging in size from 3.0 to 18.6 mm (mean, 5.3 mm) were identified as the reference standard. At diameter thresholds of 3, 4, 5, and 6 mm, the CAD system had a sensitivity of 54%, 64%, 68%, and 76%, respectively, with an average of 5.6 false positives (FPs) per scan. Without CAD, the average figures of merit (FOMs) for the six radiologists, obtained from JAFROC analysis, were 0.661, 0.729, 0.793, and 0.838 for the same nodule diameter thresholds, respectively. With CAD, the corresponding average FOMs improved to 0.705, 0.763, 0.810, and 0.862, respectively. The improvement achieved statistical significance for nodules at the 3 and 4 mm thresholds (P = .002 and .020, respectively), and did not achieve significance at 5 and 6 mm (P = .18 and .13, respectively). At a nodule diameter threshold of 3 mm, the radiologists' average sensitivity and FP rate were 0.56 and 0.67, respectively, without CAD, and 0.67 and 0.78 with CAD. CONCLUSION: CAD improves thoracic radiologists' performance for detecting pulmonary nodules smaller than 5 mm on CT examinations, which are often overlooked by visual inspection alone.