Cardiac Computed Tomography: Assessment of Coronary Inflammation and Other Plaque Features.

Unstable coronary plaques that are prone to erosion and rupture are the major cause of acute coronary syndromes. Our expanding understanding of the biological mechanisms of coronary atherosclerosis and rapid technological advances in the field of medical imaging has established cardiac computed tomography as a first-line diagnostic test in the assessment of suspected coronary artery disease, and as a powerful method of detecting the vulnerable plaque and patient. Cardiac computed tomography can provide a noninvasive, yet comprehensive, qualitative and quantitative assessment of coronary plaque burden, detect distinct high-risk morphological plaque features, assess the hemodynamic significance of coronary lesions and quantify the coronary inflammatory burden by tracking the effects of arterial inflammation on the composition of the adjacent perivascular fat. Furthermore, advances in machine learning, computational fluid dynamic modeling, and the development of targeted contrast agents continue to expand the capabilities of cardiac computed tomography imaging. In our Review, we discuss the current role of cardiac computed tomography in the assessment of coronary atherosclerosis, highlighting its dual function as a clinical and research tool that provides a wealth of structural and functional information, with far-reaching diagnostic and prognostic implications.

Noncontrast MR angiography: An update.

Both computed tomography (CT) angiography (CTA) and contrast-enhanced MR angiography (CEMRA) have proven to be useful and accurate cross-sectional imaging modalities over a wide range of vascular territories and vascular disorders. A key advantage of MRA is that, unlike CTA, it can be performed without the administration of a contrast agent. In this review article we consider the motivations for using noncontrast MRA, potential contrast mechanisms, imaging techniques, advantages, and drawbacks with respect to CTA and CEMRA, and the level of evidence for using the various MRA techniques. In addition, we explore new developments that promise to expand the reliability and range of clinical applications for noncontrast MRA, along with functional MRA capabilities not available with CTA or CEMRA. Level of Evidence: 1 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;49:355-373.

Infectious intracranial aneurysms: a systematic review of epidemiology, management, and outcomes.

Infectious intracranial aneurysms (IIAs) are a rare cerebrovascular complication of systemic infections induced by microbial infiltration and degradation of the arterial vessel wall. Studies on the epidemiology and management of IIAs are limited to case reports and retrospective single-center studies, and report a large variability in epidemiological features, management, and outcomes due to the limited sample size. We conducted a systematic review of all published papers on IIAs in the English literature using MEDLINE and SCOPUS database from January 1950 to June 2017. A total of 288 publications describing 1191 patients with IIA (1398 aneurysms) were included and reviewed for epidemiological features, disease features, treatment and outcome. All patients were merged into a single cohort and summary data are presented. The majority of reported IIAs are distally located, relatively small (<5 mm), involve the anterior circulation, are associated with a relatively high rate of rupture, and demonstrate a propensity to multiplicity of aneurysms. Sensitive diagnosis of IIAs requires digital subtraction angiography and not CT angiography or MR angiography. Treatment of ruptured, symptomatic, or enlarging IIAs has evolved over the last 50 years. Endovascular therapy is associated with a high success rate and low morbidity compared with microsurgical and medical management. A treatment algorithm for the management of patients with IIA in various contexts is proposed and the need for prospective multicenter studies is emphasized.

Underuse of risk assessment and overuse of computed tomography pulmonary angiography in patients with suspected pulmonary thromboembolism.

BACKGROUND: Evidence suggests the potential overuse of computed tomography pulmonary angiography (CTPA) in patients with suspected pulmonary thromboembolism (PTE) in the absence of consistent use of pre-test clinical prediction rules and D-dimer assays. AIM: To evaluate use and diagnostic utility of clinical prediction rules and D-dimer assay in patients with suspected PTE and quantify potentially avoidable overuse of CTPA in low risk patients. METHODS: A total of 344 consecutive patients undergoing CTPA at a tertiary hospital was studied with regards to the use of D-dimer assays and clinical prediction rules for PTE. For each patient, a modified Wells score (mWS), revised Geneva score and PISA model were calculated retrospectively; performance characteristics for each rule for PTE were determined with reference to results of CTPA. Results for the mWS and D-dimer assays (when performed) were used to estimate the overuse of CTPA according to risk category. RESULTS: Use of a clinical prediction rule was documented in only 5.0% of cases. Of 269 low-risk patients who had a calculated mWS ≤4, only 64 (23.8%) had a D-dimer assay performed, with 30 (11.1%) having a PTE on CTPA. Among 75 patients with an mWS >4, 23 (30.7%) had a PTE on CTPA (P < 0.001). Compared to other prediction rules, an mWS>4 had the highest positive predictive value (31.0%) for PTE; all rules demonstrated similar negative predictive values for low-risk scores (87-89%). After adjusting for an 11% false negative rate for PTE in patients with low-risk mWS, overuse of CTPA was reported in up to 190 (55.2%) patients. CONCLUSION: More than 50% of patients with suspected PTE may be subject to unwarranted use of CTPA in the absence of pre-test clinical prediction rules coupled with D-dimer assays.

Medicare Utilization of CT Angiography from 2001 through 2014: Continued Growth by Radiologists.

PURPOSE: To examine changes in utilization of computed tomography (CT) angiography nationally and changing relative specialty roles in examination interpretation. MATERIALS AND METHODS: Service-specific claims data for region-specific CT angiography examinations were identified using Medicare Physician Supplier Procedure Summary Master Files from 2001 through 2014. Longitudinal national utilization rates were calculated using annual Medicare enrollment data for 2001-2013. Procedure volumes by specialty group and site of service were analyzed. RESULTS: Total annual claims for CT angiography for Medicare fee for service beneficiaries increased from 64,846 to 1,709,088 (compound annual growth rate [CAGR] 29%) between 2001 and 2014. Per 1,000 beneficiaries, overall CT angiography utilization increased annually from 2.1 in 2001 to 47.6 in 2013. Overall interpretation market share increased 4% (91%-95%) for radiology. Cardiology increased from 1% in 2001 to 6% in 2007 but decreased annually to 2% in 2014. Vascular surgery market share remained < 1% throughout the study period. Growth of CT angiography in the emergency department (ED) outpaced all other sites of service, increasing from 11% to 28% (CAGR 38%). The chest was the dominant body region imaged with CT angiography, increasing from 36,984 to 914,086 (CAGR 28%). CONCLUSIONS: Utilization of CT angiography in the Medicare population increased markedly for 2001-2014, particularly in the ED, with radiologists remaining dominant providers. The chest is the most common body region imaged with CT angiography.

Trends in the Diagnosis and Outcomes of Traumatic Carotid and Vertebral Artery Dissections among Medicare Beneficiaries.

BACKGROUND: Early identification of carotid and vertebral artery dissections has been advocated to reduce stroke among trauma patients. We sought to characterize trends in the diagnosis of traumatic carotid and vertebral artery dissections and association changes in stroke rate among Medicare beneficiaries. METHODS: Using Medicare claims, we created a cohort of 5,961 beneficiaries admitted with a new traumatic carotid or vertebral artery dissection from 2001 to 2012. We calculated rates of stroke during hospitalization and 90 days of discharge. We calculated rates of carotid imaging using computed tomography-angiography, carotid duplex, and plain angiography index hospitalization. To study concurrent secular trends, we created a secondary cohort of patients admitted after any traumatic injury from 2001 to 2012 and determined rates of stroke and carotid imaging within this cohort. RESULTS: From 2001 to 2012, incidence of traumatic carotid dissection increased 72% among Medicare beneficiaries (1.1-1.76 per 100,000 patients; rate ratio [RR], 1.72; 95% CI, 1.6-1.9, P < 0.001). Among patients diagnosed with traumatic carotid or vertebral artery dissections, the combined in-hospital and 90-day stroke rate did not change significantly (4.9% in 2001; 5.2% in 2012; RR, 1.06; 95% CI, 0.93-1.20; P = 0.094). Likewise, there was little change in mortality (10.3%; RR, 1.01; 95% CI, 0.95-1.06; P = 0.88). Among all trauma patients, the use of computed tomography angiography has increased 16-fold (2-35 per 100,000 patients; RR, 16.7; 95% CI, 13-19; P < 0.0001). CONCLUSIONS: Despite increased diagnosis of carotid or vertebral artery dissection, there has been little change in stroke risk among trauma patients. Efforts to more effectively target imaging and treatment for these patients are necessary.

Comparative Trends and Downstream Outcomes of Coronary Computed Tomography Angiography and Cardiac Stress Testing in Emergency Department Patients With Chest Pain: An Administrative Claims Analysis.

OBJECTIVES: Coronary computerized tomography angiography (CCTA) is a rapidly emerging technology for the evaluation of chest pain in the emergency department (ED). We assessed trends in CCTA use and compared downstream healthcare utilization between CCTA and cardiac stress testing modalities. METHODS: Using administrative claims data (Optum Labs Data Warehouse) from over 100 million geographically diverse privately insured and Medicare Advantage enrollees across the United States, we identified 2,047,799 ED patients from January 2006 to December 2013 who presented with chest pain and had a CCTA or cardiac stress test within 72 hours. Cohorts were established based on CCTA or functional stress testing (myocardial perfusion scintigraphy [MPS], stress echocardiogram [SE], or treadmill exercise electrocardiogram [TMET]) performed within 72 hours of the ED visit. We tracked subsequent invasive cardiac procedures (invasive coronary angiography [ICA], percutaneous coronary intervention [PCI], and coronary artery bypass grafting [CABG]), repeat noninvasive testing, return ED visits, hospitalization, and the rate of acute myocardial infarction (AMI) within 30 days. We used propensity-score matching to adjust for coronary artery disease (CAD) risk factors, Charlson-Deyo comorbidity index, and baseline differences between patients selected for CCTA or cardiac stress testing. Logistic regression was used to measure adjusted associations between testing modality and outcomes. RESULTS: During the study period, CCTA use increased from 0.8% to 4.5% of all cardiac testing within 72 hours, a change of 434% (p-value for trend < 0.001), while rates of other cardiac stress testing modalities decreased (-22% for TMET [p < 0.001]; -11% for SE [p = 0.11]; -6% for MPS [p = 0.04]. After matching, there was no difference in the 30-day rate of AMI between testing modalities. Compared to MPS, CCTA was associated with higher rates of PCI (odds ratio [OR] = 1.25, 95% confidence interval [CI] = 1.04 to 1.51), and CABG (OR = 1.47; 95% CI = 1.03 to 2.13). Compared to SE and treadmill stress testing, CCTA was associated with more invasive procedures, hospitalizations, return ED visits, and repeat noninvasive testing. CONCLUSIONS: CCTA use increased fourfold during the study period and was associated with higher rates of PCI, CABG, repeat noninvasive testing, hospitalization, and return ED visits. The authors have no relevant financial information or potential conflicts to disclose.