ACR Appropriateness Criteria(®) acute nonspecific chest pain-low probability of coronary artery disease

Trends in Cardiovascular MRI and CT in the U.S. Medicare Population from 2012 to 2017

Purpose

To assess the characteristics and trends of cardiovascular MRI and CT practitioners and practice in the United States.

Materials and Methods

A retrospective cross-sectional analysis of 2012-2017 Medicare Part B physician payments from the Provider Utilization and Payment Data Physician and Other Supplier Public Use Files (POSPUF) was performed. Characteristics of cardiovascular MRI and CT, including the number of providers and examinations, provider sex and location, and physician reimbursement were analyzed. Variable means, standard deviations, and changes per year were reported and compared.

Results

In 2017, 582 physicians provided cardiovascular MRI services in 45 states, a 16.6% increase from 2016 and an 84.8% increase from 2012. A total of 1645 physicians provided cardiovascular CT services in 49 states, a 14.2% increase from 2016 and a 77.3% increase from 2012. Of the providers, 18.0% and 13.3% of cardiovascular MRI and CT providers were women, respectively, similar to providers' respective medical specialties. Only 1.0% of radiologists and 0.2% of cardiologists provided cardiovascular MRI services. A total of 3.2% of radiologists and 0.5% of cardiologists provided cardiovascular CT services. Both cardiovascular MRI use (+75.5%) and cardiovascular CT use (+97.4%) increased markedly over the 6-year study period.

Conclusion

Although the availability of cardiovascular MRI and CT is increasing, both are used less frequently in comparison with other cardiovascular imaging modalities.See also the commentary by Bierhals in this issue.Supplemental material is available for this article.© RSNA, 2021.

Comparing two methods for determining appropriateness of myocardial perfusion imaging: Criteria from the American College of Cardiology Foundation and the American College of Radiology

BACKGROUND

Appropriate use criteria (AUC) developed by the American College of Cardiology Foundation and the appropriateness criteria (AC) developed by the American College of Radiology (ACR) are two existing methods of rating appropriateness of myocardial perfusion imaging (MPI). One study found poor agreement of ratings between the two methods. However, using the most contemporary AUC from 2013, it is unknown if poor agreement still exists.

METHODS

Retrospective cohort investigation comparing patients undergoing nuclear MPI between June 2011 and September 2014. The appropriateness category was determined based on the 2013 AUC (Appropriate, may be appropriate, rarely appropriate) and the 2010 ACR AC (usually appropriate, maybe appropriate, usually not appropriate). The primary outcome was the degree of the agreement between the two methods.

RESULTS

The kappa coefficient between ACR AC and AUC was 0.32, P < 0.0001, indicating poor agreement; 40 (8%) patients were classified by the AUC but could not be classified by the ACR AC.

CONCLUSION

The two methods for rating the appropriateness of MPI have poor agreement; a potential for disagreement between providers and payers if only one method is used.

Cardiac CT in the Emergency Department: Contrasting Evidence from Registries and Randomized Controlled Trials

PURPOSE OF REVIEW

To compare outcomes between registries and randomized controlled trials of coronary computed tomographic angiography (CCTA)-based versus standard of care approaches to the initial evaluation of patients with acute chest pain.

RECENT FINDINGS

Randomized trials have demonstrated CCTA to be a safe and efficient tool for triage of low- to intermediate-risk patients presenting to the emergency department with chest pain. Recent studies demonstrate heterogeneous result using different standard of care approaches for evaluation of hard endpoints in comparison with standard evaluation. Also, there has been continued concern for increase in subsequent testing after coronary CTA. Although CCTA improves detection of coronary artery disease, it is uncertain if it will bring improvement of long-term health outcomes at this point of time. Careful analysis of the previous results and further investigation will be required to validate evaluation of hard endpoints.

Comparing two methods for determining appropriateness of myocardial perfusion imaging: Criteria from the American College of Cardiology Foundation and the American College of Radiology

BACKGROUND

Appropriate use criteria (AUC) developed by the American College of Cardiology Foundation and the appropriateness criteria (AC) developed by the American College of Radiology (ACR) are two existing methods of rating appropriateness of myocardial perfusion imaging (MPI). One study found poor agreement of ratings between the two methods. However, using the most contemporary AUC from 2013, it is unknown if poor agreement still exists.

METHODS

Retrospective cohort investigation comparing patients undergoing nuclear MPI between June 2011 and September 2014. The appropriateness category was determined based on the 2013 AUC (Appropriate, may be appropriate, rarely appropriate) and the 2010 ACR AC (usually appropriate, maybe appropriate, usually not appropriate). The primary outcome was the degree of the agreement between the two methods.

RESULTS

The kappa coefficient between ACR AC and AUC was 0.32, P < 0.0001, indicating poor agreement; 40 (8%) patients were classified by the AUC but could not be classified by the ACR AC.

CONCLUSION

The two methods for rating the appropriateness of MPI have poor agreement; a potential for disagreement between providers and payers if only one method is used.

Dissecting Costs of CT Study: Application of TDABC (Time-driven Activity-based Costing) in a Tertiary Academic Center

RATIONALE AND OBJECTIVES

The lack of understanding of the real costs (not charge) of delivering healthcare services poses tremendous challenges in the containment of healthcare costs. In this study, we applied an established cost accounting method, the time-driven activity-based costing (TDABC), to assess the costs of performing an abdomen and pelvis computed tomography (AP CT) in an academic radiology department and identified opportunities for improved efficiency in the delivery of this service.

MATERIALS AND METHODS

The study was exempt from an institutional review board approval. TDABC utilizes process mapping tools from industrial engineering and activity-based costing. The process map outlines every step of discrete activity and duration of use of clinical resources, personnel, and equipment. By multiplying the cost per unit of capacity by the required task time for each step, and summing each component cost, the overall costs of AP CT is determined for patients in three settings, inpatient (IP), outpatient (OP), and emergency departments (ED).

RESULTS

The component costs to deliver an AP CT study were as follows: radiologist interpretation: 40.1%; other personnel (scheduler, technologist, nurse, pharmacist, and transporter): 39.6%; materials: 13.9%; and space and equipment: 6.4%. The cost of performing CT was 13% higher for ED patients and 31% higher for inpatients (IP), as compared to that for OP. The difference in cost was mostly due to non-radiologist personnel costs.

CONCLUSIONS

Approximately 80% of the direct costs of AP CT to the academic medical center are related to labor. Potential opportunities to reduce the costs include increasing the efficiency of utilization of CT, substituting lower cost resources when appropriate, and streamlining the ordering system to clarify medical necessity and clinical indications.

Evaluation of appropriateness of second-generation 320-row computed tomography for coronary artery disease

The influence of newer-generation CT on the clinical indications and appropriateness of cardiac CT has not been adequately surveyed. We aimed to evaluate the distribution of appropriateness ratings and test the outcomes of cardiac CT using second-generation 320-row CT. The 2010 appropriate use criteria (AUC) were applied at the point of service to a consecutive series of patients (N = 309) who were referred for cardiac CT. The CT indication was determined based on interviews and medical records. The proportions of patients within the categories of appropriate (A), uncertain (U), inappropriate (I), and not covered were described. The prevalence of significant coronary artery disease (CAD) was also compared among the categories. The proportions were 49.2%, 25.9%, and 20.7% for appropriate, uncertain, and inappropriate indication, respectively. The indication that was not covered was only 4.2%. Significant CAD was more frequently observed for uncertain- than appropriate indication (42.5% vs 27.6%; P = 0.03), although the number of significant stenosed segments was not different (P = 0.13). The recent advancement of cardiac CT increased the proportion of uncertain scans, which were associated with a high prevalence of significant CAD.

Management of acute chest pain: A major role for coronary CT angiography

Most patients presenting with acute chest pain (ACP) at the emergency unit do not have any marked electrocardiogram abnormalities or known history of heart disease. Identifying the few patients who have, or will actually develop acute coronary syndrome in this group that is considered to be at low risk, is an actual clinical challenge for emergency department physicians. In these patients, the goal of complementary non-invasive morphological or functional imaging tests is to exclude heart disease. The diagnostic values of coronary CT angiography include a sensitivity of 96% and a negative likelihood ratio of 0.09, which are highly contributory to the diagnosis, and the integration of this imaging test into a decision tree algorithm appears to be the least expensive strategy with the best cost/effective ratio. Coronary CT angiography is indicated in the presence of ACP associated with an inconclusive electrocardiogram, in the absence of any other obvious diagnoses, when the ultrasensitive troponin assay is negative or the dynamic changes are modest, slow and/or inconclusive. Ideally, coronary CT angiography should be performed within 3 to 48hours after the initial consultation.

Applicability of the Appropriate use Criteria for Myocardial Perfusion Scintigraphy

Background

Appropriateness Criteria for nuclear imaging exams were created by American College of Cardiology (ACC) e American Society of Nuclear Cardiology (ASNC) to allow the rational use of tests. Little is known whether these criteria have been followed in clinical practice.

Objective

To evaluate whether the medical applications of myocardial perfusion scintigraphy (MPS) in a private nuclear medicine service of a tertiary cardiology hospital were suitable to the criteria of indications proposed by the American medical societies in 2005 and 2009 and compare the level of indication of both.

Methods

We included records of 383 patients that underwent MPS, November 2008 up to February 2009. Demographic characteristics, patient's origin, coronary risk factors, time of medical graduation and appropriateness criteria of medical applications were studied. The criteria were evaluated by two independent physicians and, in doubtful cases, defined by a medical expert in MPS.

Results

Mean age was 65 ± 12 years. Of the 367 records reviewed, 236 (64.3%) studies were performed in men and 75 (20.4%) were internee. To ACC 2005, 255 (69.5%) were considered appropriate indication and 13 (3.5%) inappropriate. With ACC 2009, 249 (67.8%) were considered appropriate indications and 13 (5.2%) inappropriate.

Conclusions

We observed a high rate of adequacy of medical indications for MPS. Compared to the 2005 version, 2009 did not change the results.

Influence of trigger type, tube voltage and heart rate on calcified plaque imaging in dual source cardiac computed tomography: phantom study

Background

To investigate the impact of high pitch cardiac CT vs. retrospective ECG gated CT on the quantification of calcified vessel stenoses, with assessment of the influence of tube voltage, reconstruction kernel and heart rate.

Methods

A 4D cardiac movement phantom equipped with three different plaque phantoms (12.5%, 25% and 50% stenosis at different calcification levels), was scanned with a 128-row dual source CT scanner, applying different trigger types (gated vs. prospectively triggered high pitch), tube voltages (100-120 kV) and heart rates (50–90 beats per minute, bpm). Images were reconstructed using different standard (B26f, B46f, B70f) and iterative (I26f, I70f) convolution kernels. Absolute and relative plaque sizes were measured and statistically compared. Radiation dose associated with the different methods (gated vs. high pitch, 100 kV vs. 120 kV) were compared.

Results

Compared to the known diameters of the phantom plaques and vessels both CT-examination techniques overestimated the degrees of stenoses. Using the high pitch CT-protocol plaques appeared larger (0.09 ± 0.31 mm, 2 ± 8 percent points, PP) in comparison to the ECG-gated CT-scans. Reducing tube voltage had a similar effect, resulting in higher grading of the same stenoses by 3 ± 8 PP. In turn, sharper convolution kernels lead to a lower grading of stenoses (differences of up to 5%). Pairwise comparison of B26f and I26f, B46f and B70f, and B70f and I70f showed differences of 0–1 ± 6–8 PP of the plaque depiction. Motion artifacts were present only at 90 bpm high pitch experiments. High-pitch protocols were associated with significantly lower radiation doses compared with the ECG-gated protocols (258.0 mGy vs. 2829.8 mGy CTDI_vol, p ≤ 0.0001).

Conclusion

Prospectively triggered high-pitch cardiac CT led to an overestimation of plaque diameter and degree of stenoses in a coronary phantom. This overestimation is only slight and probably negligible in a clinical situation. Even at higher heart rates high pitch CT-scanning allowed reliable measurements of plaque and vessel diameters with only slight differences compared ECG-gated protocols, although motion artifacts were present at 90 bpm using the high pitch protocols.

Impact of coronary CT angiography on surgical decision-making for coronary artery bypass graft surgery

RATIONALE AND OBJECTIVES

To determine the impact of coronary computed tomography angiography (CCTA) on treatment decisions made by cardiac surgeons and to explore barriers to implementation of CCTA as first-line imaging workup before coronary artery bypass.

MATERIALS AND METHODS

Tertiary academic medical center retrospective cohort study. Questionnaires administered to three cardiac surgeons regarding diagnosis and treatment decisions with level of confidence in decision making for 30 chest pain patients, after reviewing deidentified catheter coronary angiogram (CCA) and CCTA images on the same patients, several weeks apart.

RESULTS

All surgeons tended to report more severe disease with CCTA than CCA (P < .05). Treatment decisions differed in 12 (40%), 14 (47%), and 18 (60%) patients within each individual surgeon based on CCTA images compared to CCA images (P = .11, .01, and .02, respectively). Confidence levels were significantly higher with CCA for the diagnosis and treatment of coronary artery disease for all three surgeons (P < .05). There was a tendency toward more invasive treatment choices (angioplasty, stent insertion, or coronary artery bypass graft) when making treatment decisions based upon CCTA images.

CONCLUSIONS

Severity of disease may be overestimated by cardiac surgeons when using CCTA as a decision-making test, tending toward more invasive treatment choices compared to CCA. Additionally, cardiac surgeons may be more confident with their diagnosis and treatment based on CCA. These may be important limitations in the application of CCTA in clinical practice and may reflect the maturation of CCTA use in practice, diffusion of the technology and/or a reflection of the technology itself.

MRI for acute chest pain: current state of the art

This article reviews the magnetic resonance imaging (MRI) and angiography (MRA) techniques, imaging findings, and evidence for evaluating patients with acute chest pain due to acute pulmonary embolus (PE), aortic dissection (AD), and myocardial infarction (MI). When computed tomographic angiography (CTA) is contraindicated, MRI and MRA are important alternative imaging modalities for diagnosis and management of patients with acute PE, AD, and MI. Familiarity with the techniques, imaging findings, and evidence is critical to safely and appropriately managing patients presenting with acute chest pain.