64 slice cardiovascular CT in the emergency department: concepts and first experiences

Value of Machine Learning-based Coronary CT Fractional Flow Reserve Applied to Triple-Rule-Out CT Angiography in Acute Chest Pain

Purpose

To evaluate the additional value of noninvasive artificial intelligence (AI)-based CT-derived fractional flow reserve (CT FFR), derived from triple-rule-out coronary CT angiography for acute chest pain (ACP) in the emergency department (ED) setting.

Materials and Methods

AI-based CT FFR from triple-rule-out CT angiography data sets was retrospectively obtained in 159 of 271 eligible patients (102 men; mean age, 57.0 years ± 9.7 [standard deviation]) presenting to the ED with ACP. The agreement between CT FFR (≤ 0.80) and stenosis at triple-rule-out CT angiography (≥ 50%), as well as downstream cardiac diagnostic testing, was investigated. Furthermore, the predictive value of CT FFR for coronary revascularization and major adverse cardiac events (MACE) was assessed over a 1-year follow-up period.

Results

CT FFR and triple-rule-out CT angiography demonstrated agreement in severity of coronary artery disease (CAD) in 52% (82 of 159) of all cases. CT FFR of 0.80 and less served as a better predictor for coronary revascularization and MACE than stenosis of 50% and greater at triple-rule-out CT angiography (odds ratio, 3.4; 95% confidence interval: 1.4, 8.2 vs odds ratio, 2.2; 95% confidence interval: 0.9, 5.3) (P < .01). In the subgroup of patients with additional noninvasive cardiac testing (94 of 159), there was higher agreement as to the presence or absence of significant disease with CT FFR (55%) than with coronary triple-rule-out CT angiography (47%) (P = .23).

Conclusion

CT FFR derived from triple-rule-out CT angiography was a better predictor for coronary revascularization and MACE and showed better agreement with additional diagnostic testing than triple-rule-out CT angiography. Therefore, CT FFR may improve the specificity in identifying patients with ACP with significant CAD in the ED setting and reduce unnecessary downstream testing.© RSNA, 2020See also the commentary by Ihdayhid and Ben Zekry in this issue.

Computed Tomographic Angiography for Risk Stratification in Patients with Acute Chest Pain - The Triple Rule-out Concept in the Emergency Department

BACKGROUND

Acute chest pain is one of the most common reasons for Emergency Department (ED) visits and hospital admissions. As this could represent the first symptom of a lifethreatening condition, urgent identification of the etiology of chest pain is of utmost importance in emergency settings. Such high-risk conditions that can present with acute chest pain in the ED include Acute Coronary Syndromes (ACS), Pulmonary Embolisms (PE) and Acute Aortic Syndromes (AAS).

DISCUSSION

The concept of Triple Rule-out Computed Tomographic Angiography (TRO-CTA) for patients presenting with acute chest pain in the ED is based on the use of coronary computed tomographic angiography as a single imaging technique, able to diagnose or exclude three lifethreatening conditions in one single step: ACS, AAS and PE. TRO-CTA protocols have been proved to be efficient in the ED for diagnosis or exclusion of life-threatening conditions and for differentiation between various etiologies of chest pain, and application of the TRO-CTA protocol in the ED for acute chest pain of uncertain etiology has been shown to improve the further clinical evaluation and outcomes of these patients.

CONCLUSION

This review aims to summarize the main indications and techniques used in TRO protocols in EDs, and the role of TRO-CTA protocols in risk stratification of patients with acute chest pain.

Diagnostic Yield of Triple-Rule-Out CT in an Emergency Setting

OBJECTIVE

The objective of the present study is to quantify the diagnostic yield of triple-rule-out (TRO) CT for the evaluation of acute chest pain in emergency department patients.

MATERIALS AND METHODS

All TRO CT studies performed at our institution from 2006 to 2015 were reviewed. Scans were performed on a 256-MDCT scanner, with the use of ECG gating and a biphasic contrast injection. Radiology reports were reviewed to identify diagnoses that could explain chest pain, including coronary and noncoronary diagnoses, and significant incidental findings that did not account for the patient's presentation. The total numbers of coronary and noncoronary diagnoses and incidental findings were calculated.

RESULTS

Four of 1196 total cases that were identified were excluded from the study because of inadequate image quality. A total of 970 patients (81.4%) had a negative study result without a significant coronary or noncoronary diagnosis. A total of 139 patients (11.7%) had significant coronary artery disease (50% stenosis or greater). One hundred six patients (8.9%) had a noncoronary diagnosis that could explain chest pain (p < 0.02), most commonly pulmonary embolism (28 patients [2.3%]), aortic aneurysm (24 patients [2.0%]), or pneumonia (20 patients [1.7%]). Thirty cases (27.3%) of pulmonary embolism and aortic pathologic findings would not have been detected with coronary CT angiography because of unopacified right-side circulation or limited z-axis coverage. A total of 528 incidental findings not considered to explain chest pain were noted in 418 patients (35.1%).

CONCLUSION

In 8.9% of patients, TRO CT detected a significant noncoronary diagnosis that could explain acute chest pain, including pathologic findings that would not be identified on dedicated coronary CT angiography.

Coronary computed tomographic angiography in the emergency room: state of the art

Chest pain is a common complaint in the emergency department often necessitating testing to exclude underlying obstructive coronary artery disease. While the traditional evaluation of patients with suspected acute coronary syndrome often consists of serial electrocardiograms and cardiac biomarkers, followed by selective use of stress testing for further risk stratification, this approach is costly and inefficient. Recently, coronary computed tomographic angiography (CTA) has offered an alternative approach with a high sensitivity and negative predictive value to exclude obstructive coronary artery disease that can rapidly identify patients with low rates of downstream major adverse cardiac events. In this review, the authors provide an overview of available data on the use of CTA for evaluating acute chest pain, while emphasizing its advantages and disadvantages compared to existing strategies. In addition, we provide a suggested algorithm to identify how CTA can be incorporated into the evaluation of acute chest pain and discuss tips for successful implementation of CTA in the emergency department.

Triple rule-out computed tomographic angiography for chest pain: a diagnostic systematic review and meta-analysis

OBJECTIVES

The objective was to compare the image quality, diagnostic accuracy, radiation exposure, and contrast volume of "triple rule-out" (TRO) computed tomography (CT) to other diagnostic modalities commonly used to evaluate patients with nontraumatic chest pain (dedicated coronary, pulmonary embolism [PE], and aortic dissection CT; invasive coronary angiography; and nuclear stress testing).

METHODS

Four electronic databases were searched, along with reference lists and contacted content experts, for relevant studies from inception until October 2012. Eligible studies enrolled patients with nontraumatic chest pain, shortness of breath, suspected acute coronary syndrome (ACS), PE, or aortic dissection; used at least 64-slice CT technology; and compared TRO CT to another diagnostic modality.

RESULTS

Eleven studies enrolling 3,539 patients (791 TRO and 2,748 non-TRO) were included (one randomized controlled trial and 10 observational). There was no significant difference in image quality between TRO and dedicated CT scans. TRO CT had the following pooled diagnostic accuracy estimates for coronary artery disease: sensitivity of 94.3% (95% confidence interval [CI] = 89.1% to 97.5%), specificity of 97.4% (95% CI = 96.1% to 98.4%), positive likelihood ratio (LR+) of 17.71 (95% CI = 3.92 to 79.96), and negative likelihood ratio (LR-) of 0.08 (95% CI = 0.02 to 0.27). There were insufficient numbers of patients with PE or aortic dissection to generate diagnostic accuracy estimates for these conditions. Use of TRO CT involved greater radiation exposure (mean difference [MD] = 4.84 mSv, 95% CI = 1.65 to 8.04 mSv) and contrast exposure (MD = 38.0 mL, 95% CI = 28.1 to 48.0 mL) compared to non-TRO CT patients.

CONCLUSIONS

Triple rule-out CT is highly accurate for detecting coronary artery disease. Given the low (<1%) prevalence of PE and aortic dissection in the included studies, and the increased radiation and contrast exposure, there are insufficient data to recommend use of TRO CT in the diagnosis of these conditions.

Diagnostic accuracy and clinical outcomes of ECG-gated, whole chest CT in the emergency department

PURPOSE

The purpose of this study was to assess the diagnostic accuracy and one year prognosis of whole chest, "multiple rule out" CT for coronary artery disease (CAD) in Emergency Department patients.

METHODS AND FINDINGS

One hundred and two Emergency Department patients at low to intermediate risk of acute coronary syndrome (ACS), pulmonary embolism and/or acute aortic syndrome underwent a research 64 channel ECG-gated, whole chest CT and a standard of care evaluation. Patients were classified with obstructive CAD with either a coronary CT stenosis greater than 50% or a non-evaluable coronary segment. SOC and 3 month follow up data were used to determine an adjudicated clinical diagnosis. The diagnostic ability of obstructive CAD on CT to identify clinical diagnoses was determined. Patients were followed up for 1 year for cardiac events. Seven (7%) patients were diagnosed with ACS. CT sensitivity to detect obstructive CAD in ACS patients was 100% (95% CI 65%, 100%), negative predictive value 100% (96%, 100%), specificity 88% (80%, 94%), and positive predictive value 39% (17%, 64%). Pulmonary embolism and acute aortic syndrome were not identified in any patients. No cardiac events occurred in patients without obstructive CAD over 1 year.

CONCLUSIONS

Whole chest CT has high sensitivity and negative predictive value for ACS with excellent one year prognosis in patients without obstructive CAD on CT. The frequency of pulmonary embolism or acute aortic syndrome and the higher radiation dose suggest whole chest CT should be limited to select patients. ClinicalTrials.org #: NCT00855231.

Acute aortic syndromes

Acute aortic syndrome is a term that describes one of a number of different pathologic entities. Each of these conditions requires urgent or emergent evaluation and may possibly require surgical intervention. However, both entities may be unfamiliar to the nonsurgical (and in some cases, surgical) practitioner and they may mimic more common diseases or be missed entirely. An understanding of the processes, nomenclature, and management options is critical in optimizing patient care.

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

This document outlines the usefulness of available diagnostic imaging for patients without known coronary artery disease and at low probability for having coronary artery disease who do not present with classic signs, symptoms, or electrocardiographic abnormalities indicating acute coronary syndrome but rather with nonspecific chest pain leading to a differential diagnosis, including pulmonary, gastrointestinal, or musculoskeletal pathologies. A number of imaging modalities are available to evaluate the broad spectrum of possible pathologies in these patients, such as chest radiography, multidetector CT, MRI, ventilation-perfusion scans, cardiac perfusion scintigraphy, transesophageal and transthoracic echocardiography, PET, spine and rib radiography, barium esophageal and upper gastrointestinal studies, and abdominal ultrasound. It is considered appropriate to start the assessment of these patients with a low-cost, low-risk diagnostic test such as a chest x-ray. Contrast-enhanced gated cardiac and ungated thoracic multidetector CT as well as transthoracic echocardiography are also usually considered as appropriate in the evaluation of these patients as a second step if necessary. A number of rest and stress single-photon emission CT myocardial perfusion imaging, ventilation-perfusion scanning, aortic and chest MR angiographic, and more specific x-ray and abdominal examinations may be appropriate as a third layer of testing, whereas MRI of the heart or coronary arteries and invasive testing such as transesophageal echocardiography or selective coronary angiography are not considered appropriate in these patients. Given the low risk of these patients, it is mandated to minimize radiation exposure as much as possible using advanced and appropriate testing protocols. The ACR Appropriateness Criteria® are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Unusual complications of endovascular repair of the thoracic aorta: MDCT findings

With the development of minimally invasive surgical techniques, endovascular stent-graft placement has become an accepted and widely used alternative to the traditional surgical repair of aortic disease and is gaining acceptance as the treatment of choice. Many studies show that endovascular stent-graft therapy is safe and effective, although complications related to this treatment are also recognised. Although the incidence of major complication is low, neurological sequelae remain the major concern of endovascular repair. With growing experience, however, the spectrum of mid- and long-term complications has broadened to include potentially disastrous events, other than paraplegia or stroke, that require diligent surveillance. Three-dimensional data sets acquired quickly by multidetector computed tomography (MDCT) allow multiplanar reformations and 3D viewing, as well as quantitative assessment of vessel lumens, walls and surroundings. Although a large portion of radiologists will not be involved in the actual endograft deployment, many will be involved in the interpretation of postprocedural surveillance studies. Accordingly, the goal of this report is to summarise our experience with the presentation, diagnostic approach, management and outcomes of these unusual, but potentially catastrophic, postendovascular aortic repair complications to highlight their significance and increase familiarity with them among the imaging community. Increasing awareness of these complications may facilitate rapid diagnosis and/or triage and treatment.

Coronary computed tomography angiography for the evaluation of patients with acute chest pain

Acute chest pain is a common presenting complaint of patients attending emergency room departments. Despite this, it can often be challenging to completely exclude a diagnosis of acute coronary syndrome following an initial standard clinical and biochemical evaluation. As a result of this, patients are often admitted to hospital until the treating clinician is satisfied that this diagnosis can be excluded. This process imparts a significant health economic burden by not only increasing hospital bed occupancy rates but also by the unnecessary layering of diagnostic investigations. With the rapid advances in coronary computed tomography angiography (CTA), there has been considerable interest in whether coronary CTA may be a viable alternative to this current standard care. We review the current literature and supporting evidence for utilising coronary CTA in the evaluation of patients presenting with acute chest pain in terms of its diagnostic accuracy, safety, cost-effectiveness and prognostic implications.

MDCT in diagnosing acute aortic syndromes: reviewing common and less common CT findings

Nontraumatic acute thoracic aortic syndromes (AAS) describe a spectrum of life-threatening aortic pathologies with significant implications on diagnosis, therapy and management. In this context, multidetector computed tomography (MDCT) is the gold standard due to its intrinsic diagnostic value; its performance approaches 100% sensitivity and specificity, and it is accepted as a first-line modality for suspected acute aortic disease. MDCT allows early recognition and characterisation of acute aortic syndromes as well as the presence of any associated complications - findings that are essential for optimising treatment and improving clinical outcomes. Although classic CT findings have long been known, other unusual signs are continually reported in the medical literature. We reviewed the classic and less common CT findings, correlating them with pathophysiology, timing and management options, to achieve a definite and timely diagnostic and therapeutic definition.

[Radiologists in the emergency department: when and how to use multislice CT]

Chest pain is a challenging clinical problem in the emergency department. Despite advances in clinical diagnosis, many patients with atypical chest pain are needlessly hospitalized and others are mistakenly discharged. Faced with the specific clinical situation in which a patient has chest pain, an initially normal or inconclusive electrocardiogram, and normal cardiac biomarkers, multislice CT has proven useful for ruling out the conditions that involve the greatest morbidity and mortality and for establishing the cause of pain. This article reviews the current usefulness of multislice CT in the diagnostic workup of patients presenting at the emergency department with chest pain. We review the technique, define the most appropriate population, describe the acquisition protocols, and discuss the advantages and disadvantages of each study protocol.

Cardiac CT in the emergency department: convincing evidence, but cautious implementation

In clinical practice, assessment of chest pain patients presenting to the emergency department is difficult and the work-up can be lengthy and costly. There is growing evidence supporting the use of coronary computed tomography angiography (CTA) in early assessment of patients presenting with acute chest pain to the emergency department. CTA appears to be a faster and more accurate way to diagnosis or rule out coronary stenosis, leading to reduced hospital admissions, decreased time in the ED and lower costs. The focus of this article is to review the current literature of the use of Coronary CTA and "triple rule out" protocols in the emergency department setting and to provide a chest pain algorithm, showing how Coronary CTA can be implemented effectively in clinical practice. Potential pitfalls and requirements for implementation will also be discussed.

The diagnostic performance of multi-slice coronary computed tomographic angiography: a systematic review

BACKGROUND

The use of coronary computed tomographic angiography (CCTA) for evaluation of patients with suspected coronary artery disease (CAD) is growing rapidly, yet questions remain regarding its diagnostic accuracy and its impact on clinical decision-making and patient outcomes.

METHODS

A systematic literature review was conducted to identify studies examining (a) CCTA's diagnostic accuracy; and (b) the impact of CCTA on clinical decision-making and/or patient outcomes. Diagnostic accuracy estimates were limited to patient-based analyses of occlusion; outcome studies were eligible for inclusion if they involved patients at low-to-intermediate risk of CAD. Pooled accuracy estimates were derived using bivariate random effects models; non-diagnostic CCTA results were conservatively assumed to be false positives.

RESULTS

A total of 42 diagnostic accuracy studies and 11 patient outcome studies were identified. The pooled mean sensitivity for CCTA in primary analyses was 98% (95% CI: 96%, 99%); specificity was 85% (81%, 89%). A small number of outcome studies set primarily in the emergency department found triage of low-risk patients using CCTA produced no serious adverse outcomes and was time-saving relative to standard triage care. Outcome studies in the outpatient setting were limited to four case series that did not directly compare patient care or outcomes with those of contemporaneous patients evaluated without CCTA.

CONCLUSIONS

CCTA appears to have high diagnostic accuracy in patients with suspected CAD, but its potential impact on clinical decision-making and patient outcomes is less well-understood, particularly in non-emergent settings.

Usefulness of comprehensive cardiothoracic computed tomography in the evaluation of acute undifferentiated chest discomfort in the emergency department (CAPTURE)

Newer cardiac computed tomographic (CT) technology has permitted comprehensive cardiothoracic evaluations for coronary artery disease, pulmonary embolism, and aortic dissection within a single breath hold, independent of the heart rate. We conducted a randomized diagnostic trial to compare the efficiency of a comprehensive cardiothoracic CT examination in the evaluation of patients presenting to the emergency department with undifferentiated acute chest discomfort or dyspnea. We randomized the emergency department patients clinically scheduled to undergo a dedicated CT protocol to assess coronary artery disease, pulmonary embolism, or aortic dissection to either the planned dedicated CT protocol or a comprehensive cardiothoracic CT protocol. All CT examinations were performed using a 64-slice dual source CT scanner. The CT results were immediately communicated to the emergency department providers, who directed further management at their discretion. The subjects were then followed for the remainder of their hospitalization and for 30 days after hospitalization. Overall, 59 patients (mean age 51.2 ± 11.4 years, 72.9% men) were randomized to either dedicated (n = 30) or comprehensive (n = 29) CT scanning. No significant difference was found in the median length of stay (7.6 vs 8.2 hours, p = 0.79), rate of hospital discharge without additional imaging (70% vs 69%, p = 0.99), median interval to exclusion of an acute event (5.2 vs 6.5 hours, p = 0.64), costs of care (p = 0.16), or the number of revisits (p = 0.13) between the dedicated and comprehensive arms, respectively. In addition, radiation exposure (11.3 mSv vs 12.8 mSv, p = 0.16) and the frequency of incidental findings requiring follow-up (24.1% vs 33.3%, p = 0.57) were similar between the 2 arms. Comprehensive cardiothoracic CT scanning was feasible, with a similar diagnostic yield to dedicated protocols. However, it did not reduce the length of stay, rate of subsequent testing, or costs. In conclusion, although this "triple rule out" protocol might be helpful in the evaluation of select patients, these findings suggest that it should not be used routinely with the expectation that it will improve efficiency or reduce resource use.

Assessment of right ventricular function in acute pulmonary embolism using ECG-synchronized MDCT

OBJECTIVE

The purpose of this article is to determine the independent predictors of right ventricular (RV) dysfunction in patients with acute pulmonary embolism (PE) and to assess the relationship between RV ejection fraction (EF) and PE load.

SUBJECTS AND METHODS

Breath-hold CT of the chest was performed for 64 patients with PE (33 men and 31 women; mean [± SD] age, 58.6 ± 16.5 years). In addition, ECG-synchronized cardiac CT was performed to determine the RV and left ventricular (LV) EFs. PE load was determined using the Qanadli obstruction index. Multivariable regression analysis was performed to determine independent predictors of RV dysfunction (defined as EF < 35%). In addition, the relationship between RV EF and PE load was assessed by receiver operating characteristic (ROC) curves.

RESULTS

RV dysfunction was independently predicted by a PE load greater than 50% (odds ratio, 40.17; 95% CI, 4.22-382.67) and an LV EF less than 45% (odds ratio, 31.18; 95% CI, 2.00-487.09; p < 0.05 for both). Curve analysis revealed that a PE load greater than 50% had a sensitivity of 82% and a specificity of 85% to identify an RV EF less than 35%. Conversely, an RV EF less than 35% had a sensitivity of 93% and a specificity of 67% to predict a PE load greater than 50%.

CONCLUSION

RV dysfunction (defined as RV EF < 35%) in patients with acute PE is highly sensitive to define a PE load greater than 50%. Furthermore, RV dysfunction is independently predicted by an obstruction index greater than 50% or an LV EF less than 45%. Assessment of RV function by ECG-synchronized CT may become useful for guiding therapy.

CT of coronary artery disease

Technical innovation is rapidly improving the clinical utility of cardiac computed tomography (CT) and will increasingly address current technical limitations, especially the association of this test with relatively high levels of radiation. Guidelines for appropriate indications are in place and are evolving, with an increasing evidence base to ensure the appropriate use of this modality. New technologies and new applications, such as myocardial perfusion imaging and dual-energy CT, are being explored and are widening the scope of coronary CT angiography from mere coronary artery assessment to the integrative analysis of cardiac morphology, function, perfusion, and viability. The scientific evaluation of coronary CT angiography has left the stage of feasibility testing and increasingly, evidence-based data are accumulating on outcomes, prognosis, and cost-effectiveness. In this review, these developments will be discussed in the context of current pivotal transitions in cardiovascular disease management and their potential influence on the current role and future fate of coronary CT angiography will be examined.

Comparison of image quality and arterial enhancement with a dedicated coronary CTA protocol versus a triple rule-out coronary CTA protocol

RATIONALE AND OBJECTIVES

To compare the image quality of dedicated coronary computed tomography angiography (cCTA) to that of triple rule-out (TRO) CTA designed to evaluate the coronary arteries, thoracic aorta, and pulmonary arteries.

MATERIALS AND METHODS

Consecutive cCTA examinations performed by a single radiologist over 1 year were reviewed. Biphasic injection protocols were employed: 70 mL of optiray-350 followed by 40 mL of saline injected at 5.5 mL/second for dedicated cCTA; 70 mL of optiray-350 followed by 25 mL of the contrast diluted with 25 mL of saline injected at 5.0 mL/second for TRO-CTA. Two independent cardiovascular radiologists reviewed the coronary vessels in each case and rated diagnostic image quality on a 5 point scale (1, suboptimal; 3, adequate; 5, excellent). Vascular enhancement was measured in the coronary arteries, aorta, and pulmonary arteries.

RESULTS

There was excellent interobserver agreement between the cardiovascular radiologists (kappa = 0.91). Coronary image quality score were similar among 260 dedicated cCTA studies and 168 TRO-CTA studies (mean: 3.8-3.9. P > .18). At least one coronary segment demonstrated suboptimal image quality in 8% of examinations, including 18 dedicated cCTA studies and 16 TRO studies (P = .94). Enhancement was greater in the distal thoracic aorta of TRO patients (336 vs. 311 Hounsfield units; P = .01); no other significant differences in enhancement were identified in the aorta and coronary arteries of dedicated cCTA and TRO studies. Vascular enhancement was adequate for diagnostic evaluation of the pulmonary arteries in all TRO studies.

CONCLUSIONS

A TRO-CTA protocol using 95 mL of contrast can provide comparable coronary image quality and coronary vascular enhancement as compared to dedicated cCTA with 70 mL of contrast.

Low-risk patients with chest pain in the emergency department: negative 64-MDCT coronary angiography may reduce length of stay and hospital charges

OBJECTIVE

The current standard-of-care workup of low-risk patients with chest pain in an emergency department takes 12-36 hours and is expensive. We hypothesized that negative 64-MDCT coronary angiography early in the workup of such patients may enable a shorter length of stay and reduce charges.

MATERIALS AND METHODS

The standard-of-care evaluation consisted of serial cardiac enzyme tests, ECGs, and stress testing. After informed consent, we added cardiac CT early in the standard-of-care workup of 53 consecutive patients. Fifty patients had negative CT findings and were included in this series. The length of stay and charges were analyzed using actual patient data for all patients in the standard-of-care workup and for two earlier discharge scenarios based on negative cardiac CT results: First, CT plus serial enzyme tests and ECGs during an observation period followed by discharge if all were negative; and second, CT plus one set of enzyme tests and one ECG followed by discharge if all were negative. Comparisons were made using paired Student's t tests.

RESULTS

For standard of care and the two CT-based earlier discharge analyses, the mean lengths of stay were 25.4, 14.3, and 5.0 hours; mean charges were $7,597, $6,153, and $4,251. Length of stay and charges were both significantly less (p < 0.001) for the two CT-based analyses.

CONCLUSION

In low-risk patients with chest pain, discharge from the emergency department based on negative cardiac CT, enzyme tests, and ECG may significantly decrease both length of stay and hospital charges compared with the standard of care.

Quick identification of acute chest pain patients study (QICS)

Background

Patients with acute chest pain are often referred to the emergency ward and extensively investigated. Investigations are costly and could induce unnecessary complications, especially with invasive diagnostics. Nevertheless, chest pain patients have high mortalities. Fast identification of high-risk patients is crucial. Therefore several strategies have been developed including specific symptoms, signs, laboratory measurements, and imaging.

Methods/Design

The Quick Identification of acute Chest pain Study (QICS) will investigate whether a combined use of specific symptoms and signs, electrocardiography, routine and new laboratory measures, adjunctive imaging including electron beam (EBT) computed tomography (CT) and contrast multislice CT (MSCT) will have a high diagnostic yield for patients with acute chest pain. All patients will be investigated according a standardized protocol in the Emergency Department. Serum and plasma will be frozen for future analysis for a wide range of biomarkers at a later time point. The primary endpoint is the safe recognition of low-risk chest pain patients directly at presentation. Secondary endpoint is the identification of a wide range of sensitive predictive clinical markers, chemical biomarkers and radiological markers in acute chest pain patients. Chemical biomarkers will be compared to quantitative CT measurements of coronary atherosclerosis as a surrogate endpoint. Chemical biomarkers will also be compared in head to head comparison and for their additional value.

Discussion

This will be a very extensive investigation of a wide range of risk predictors in acute chest pain patients. New reliable fast and cheap diagnostic algorithm resulting from the test results might improve chest pain patients' prognosis, and reduce unnecessary costs and diagnostic complications.

Usefulness of routine use of multidetector coronary computed tomography in the "fast track" evaluation of patients with acute chest pain

Recently published American Heart Association/American College of Cardiology guidelines suggest that multidetector computed tomography (MDCT) may be appropriate for investigating acute chest pain (ACP). Only a few small studies have evaluated the use of MDCT in ACP, where it was not part of routine investigation. We sought to evaluate the routine use of MDCT in a large cohort of patients presenting with ACP in a real-world setting. We studied 785 consecutive patients with ACP who underwent evaluation by MDCT or myocardial perfusion scintigraphy after an observation period of > or = 12 hours. Patients with findings suggestive of significant coronary artery disease (CAD) were referred to coronary angiography. Forty-two patients were hospitalized due to evidence of myocardial ischemia and 44 patients were discharged after the observation period. Of the remaining 699 patients, 340 underwent MDCT and 359 myocardial perfusion scintigraphy. In 22 patients (7%) multidetector computed tomogram showed significant CAD and in 32 (9%) patients myocardial perfusion scintigram showed significant ischemia. Significant CAD was confirmed by coronary angiography in 65% and 60%, respectively. Multidetector computed tomogram was nondiagnostic in 31 patients (9%). Extracardiac findings that might be related to ACP and/or necessitated further investigation were demonstrated by multidetector computed tomogram in 71 patients (21%). During 3-month follow-up, 1 patient (0.3%) with negative multidetector computed tomographic and 9 (3%) with negative myocardial perfusion scintigraphic findings developed an acute coronary syndrome or died. Rehospitalization, due to recurrent chest pain, occurred in 9 patients (3.3%) and 21 patients (7.2%), respectively. In conclusion, MDCT could be an appropriate alternative to traditional noninvasive techniques for investigating ACP.

Significance of cardiac computed tomography incidental findings in acute chest pain

BACKGROUND

Coronary computed tomography angiography might improve the management of patients presenting to the emergency department with acute chest pain; however, noncoronary incidental findings are frequently detected. The prevalence and clinical significance of these findings have not been well described.

METHODS

Consecutive patients presenting to the emergency department with acute chest pain and inconclusive initial evaluation between May 2005 and May 2007 underwent 64-slice coronary computed tomography angiography before hospital admission with noncoronary incidental findings immediately reported. An expert panel adjudicated which incidental findings changed in-hospital patient management, and projections for additional testing were based on standard medical practice.

RESULTS

Among 395 patients (37.0% were female, mean age 53 +/- 12 years), incidental findings were detected in 44.8% (n = 177): noncalcified pulmonary nodules (n = 94, 23.8%), simple liver cysts (n = 26, 6.6%), calcified pulmonary nodules (n = 16, 4.1%), and contrast-enhancing liver lesions (n = 9, 2.3%). In-hospital management was changed because of incidental finding reporting in 5 patients (1.3%), and a potential alternative diagnosis was offered in another 16 patients (4.1%). Subsequent diagnostic imaging tests were recommended in 81 patients (20.5%), including 74 chest computed tomography scans. After 6 months, biopsy was performed in 3 patients, revealing cancer in 2 (0.5%) who underwent successful tumor resection.

CONCLUSION

Clinically important findings are detected in up to 5% of patients with a lead symptom of acute chest pain and low to intermediate likelihood of acute coronary syndrome, but only few directly change patient management; 21% are recommended for further imaging tests, resulting in invasive procedures and detection of cancer in few patients.

A comprehensive electrocardiogram-gated 64-slice multidetector computed tomography imaging protocol to visualize the coronary arteries, thoracic aorta, and pulmonary vasculature in a single breath hold

OBJECTIVES

Advances in computed tomography technology may permit the evaluation of coronary disease, aortic dissection, and pulmonary embolism with a single contrast bolus and breath hold. We sought to determine whether 64-slice computed tomography angiography (CTA) allows for simultaneous visualization of the coronary arteries, thoracic aorta, and pulmonary arteries (coronary, aorta, pulmonary [CAP]) with image quality comparable to routine CTA protocols.

MATERIALS AND METHODS

We prospectively enrolled 20 patients who underwent CAP CTA. Image quality of CAP CTA was assessed qualitatively and quantitatively and compared with dedicated coronary (n = 20) and pulmonary (n = 10) CTA data sets using matched controls.

RESULTS

The mean amount of contrast and radiation dose was 132 +/- 10 mL and 17.8 +/- 1.8 mSv, 78 +/- 9 mL and 13.7 +/- 3.4 mSv, and 135 mL and 11.9 +/- 1.5 mSv for CAP CTA, coronary CTA, and pulmonary CTA, respectively (P = 0.001). There was no difference in overall image quality (P = 0.88), presence of motion artifacts (P = 0.40), or enhancement of the proximal coronary arteries (median [interquartile range for contrast-noise ratio was 12.5 9.9-15.2 vs 13.1 10.3-16.9; P = 0.17]) or thoracic aorta (264 [113-326] vs 245 [107-295]; P = 0.34) between CAP CTA and the dedicated coronary CTA, respectively. However, contrast attenuation was higher in the pulmonary arteries with CAP CTA (363 [253-424]) versus the standard pulmonary CTA protocol (235 [182-269]; P = 0.0001).

CONCLUSIONS

: Using an individually tailored single contrast injection, CAP CTA permits simultaneous visualization of the coronary arteries, thoracic aorta, and pulmonary arteries with excellent image quality. Further research is necessary to determine whether this protocol may enhance triage of patients with undifferentiated acute chest pain.

Evaluation of a "triple rule-out" coronary CT angiography protocol: use of 64-Section CT in low-to-moderate risk emergency department patients suspected of having acute coronary syndrome

PURPOSE

To determine whether coronary computed tomographic (CT) angiography "triple rule-out" evaluation of emergency department (ED) patients presenting with symptoms suggestive of acute coronary syndrome (ACS) can help identify a subset of patients who can be discharged without adverse clinical outcomes within 30 days.

MATERIALS AND METHODS

This protocol was approved by the university institutional review board. Each patient provided written informed consent prior to inclusion. Coronary CT angiography was performed in 201 consecutive low-to-moderate risk ACS patients. A triple rule-out protocol was used to evaluate for coronary disease, pulmonary embolism, aortic dissection, and other thoracic disease. Four patients were excluded because of technical problems. The remaining subjects underwent a 30-day follow-up.

RESULTS

A disease process other than coronary atherosclerosis that explained the presenting symptoms was diagnosed in 22 (11%) of 197 patients. Clinically important noncoronary diagnoses that did not explain patient symptoms were identified in 27 (14%) of 197 additional patients. With respect to coronary artery disease, 10 patients had severe disease (>70% stenosis), 12 had moderate disease (50%-70% stenosis), 46 had mild disease (up to 50% stenosis), and 129 had no disease. No further diagnostic testing was performed in 133 (76%) of 175 of patients with no to mild coronary disease. At 30-day follow-up, the negative predictive value of coronary CT angiography with no more than mild disease was 99.4%. There were no adverse outcomes at 30 days.

CONCLUSION

Triple rule-out coronary CT angiography evaluation of low-to-moderate risk ACS patients presenting to the ED provided a noncoronary diagnosis that explained the presenting complaint in 11% of patients, suggested the presence of significant moderate-to-severe coronary disease in 11% (22 of 197) of patients, and precluded additional diagnostic cardiac testing in the majority of patients with no adverse outcomes at 30-day follow-up.

Temporally targeted imaging method applied to ECG-gated computed tomography: preliminary phantom and in vivo experience

RATIONALE AND OBJECTIVES

Existing cardiac imaging methods do not allow for improved temporal resolution when considering a targeted region of interest (ROI). The imaging method presented here enables improved temporal resolution for ROI imaging (namely, a reconstruction volume smaller than the complete field of view). Clinically, temporally targeted reconstruction would not change the primary means of reconstructing and evaluating images, but rather would enable the adjunct technique of ROI imaging, with improved temporal resolution compared with standard reconstruction ( approximately 20% smaller temporal scan window). In gated cardiac computed tomography (CT) scans improved temporal resolution directly translates into a reduction in motion artifacts for rapidly moving objects such as the coronary arteries.

MATERIALS AND METHODS

Retrospectively electrocardiogram gated coronary angiography data from a 64-slice CT system were used. A motion phantom simulating the motion profile of a coronary artery was constructed and scanned. Additionally, an in vivo study was performed using a porcine model. Comparisons between the new reconstruction technique and the standard reconstruction are given for an ROI centered on the right coronary artery, and a pulmonary ROI.

RESULTS

In both a well-controlled motion model and a porcine model results show a decrease in motion induced artifacts including motion blur and streak artifacts from contrast enhanced vessels within the targeted ROIs, as assessed through both qualitative and quantitative observations.

CONCLUSION

Temporally targeted reconstruction techniques demonstrate the potential to reduce motion artifacts in coronary CT. Further study is warranted to demonstrate the conditions under which this technique will offer direct clinical utility. Improvement in temporal resolution for gated cardiac scans has implications for improving: contrast enhanced CT angiography, calcium scoring, and assessment of the pulmonary anatomy.

Dual-source CT for chest pain assessment

Comprehensive CT angiography protocols offering a simultaneous evaluation of pulmonary embolism, coronary stenoses and aortic disease are gaining attractiveness with recent CT technology. The aim of this study was to assess the diagnostic accuracy of a specific dual-source CT protocol for chest pain assessment. One hundred nine patients suffering from acute chest pain were examined on a dual-source CT scanner with ECG gating at a temporal resolution of 83 ms using a body-weight-adapted contrast material injection regimen. The images were evaluated for the cause of chest pain, and the coronary findings were correlated to invasive coronary angiography in 29 patients (27%). The files of patients with negative CT examinations were reviewed for further diagnoses. Technical limitations were insufficient contrast opacification in six and artifacts from respiration in three patients. The most frequent diagnoses were coronary stenoses, valvular and myocardial disease, pulmonary embolism, aortic aneurysm and dissection. Overall sensitivity for the identification of the cause of chest pain was 98%. Correlation to invasive coronary angiography showed 100% sensitivity and negative predictive value for coronary stenoses. Dual-source CT offers a comprehensive, robust and fast chest pain assessment.

Noninvasive cardiac imaging with computed tomography

Despite major improvements in the treatment of heart disease, it remains a major source of morbidity and mortality on a global scale. Currently, invasive coronary angiography remains the gold standard for identification of obstructive coronary artery disease. However, recent advances in computerized tomographic (CT) techniques of the heart allow for accurate, noninvasive characterization of atherosclerotic coronary disease and other cardiac abnormalities. The calculation of coronary artery calcium scores with electron beam CT has largely been supplanted by high-resolution CT angiography using multislice detectors (MSCT) which can provide detailed multidimensional visualization of cardiac structures. Although evaluation of obstructive coronary disease is the primary use of MSCT, its use in identifying congenital defects, planning thoracic procedures and characterizing cardiac function continues to grow. Accordingly, appropriate incorporation of MSCT/CT angiography into clinical practice continues to be defined. Several limitations to MSCT remain which reduce its accuracy, such as in patients with arrhythmia and in patients with either coronary stents or heavily calcified coronaries. Despite its current limitations, MSCT remains a rapidly advancing field and an increasingly valuable tool for the noninvasive evaluation of cardiac pathology.

Litigation in Nontraumatic Aortic Diseases – A Tempest in the Malpractice Maelstrom

OBJECTIVES

Physicians are vulnerable to highly litigated thoracic aortic diseases. On the basis of a review of litigated cases, we aim to determine legally protective strategies for physicians and methods to improve treatment.

METHODS

Thirty-three nontraumatic, thoracic aorta-related legal cases were analyzed.

RESULTS

Twenty-three patients (69.7%) had dissections (21 ascending, 2 descending), 8 (24.2%) had aneurysms and 2 had miscellaneous other phenomena (1 coarctation and 1 iatrogenic descending aortic rupture). The adverse event was death in 30 (90.9%) patients and paraplegia or stroke in 3 (9.1%). Allegations included: failure/delay in diagnosis (19), delay in surgery (4), error in surgical technique (5), failure to prevent paraplegia (2) and miscellaneous (3). Medical treatment was retrospectively judged suboptimal in 22 cases (66.6%) for reasons consonant with allegations.

CONCLUSIONS

Aortic disease can be diagnostically elusive, as 'the great masquerader'. Emergency physicians must maintain a high index of suspicion for aneurysm and dissection. The D-dimer test can effectively rule out aortic dissection. 'Triple rule-out' CT scans should be performed liberally. CT scan readers must remember to evaluate the aorta. Operating room administrators must be aware that postponing a scheduled thoracic aortic case may result in interim rupture and consequent litigation. With virulent thoracic aortic diseases, adverse outcome itself does not imply substandard care.

Comprehensive cardiovascular ECG-gated MDCT as a standard diagnostic tool in patients with acute chest pain

Acute myocardial infarction, pulmonary embolism, and aortic dissection are diseases associated with acute chest pain and may lead to severe morbidity and mortality. These diseases may not be trivial to diagnose in the settings of emergency room. ECG-gated multi-detector computed tomography (MDCT), already established for the assessment of pulmonary embolism and aortic dissection, provides reliable information regarding the triage of patients with acute coronary syndrome in the emergency room. MDCT recently appeared to be logistically feasible and a promising comprehensive method for the evaluation of cardiac and non-cardiac chest pain in emergency department patients. The possibility to scan the entire thorax visualizing the thoracic aorta, the pulmonary arteries, and the coronary arteries could provide a new approach to the triage of acute chest pain. The inherent advantage of MDCT with cardiac state-of-the-art capabilities is the rapid investigation of the main sources of acute chest pain with a high negative predictive value. Recent studies also reports an advantage in terms of costs. With current evidence, the selection of patients with acute chest pain candidates to MDCT should remain restricted to avoid unjustified risk of ionizing radiation.

Can ECG-gated MDCT be considered an obligatory step to plan and manage a new chest-pain unit?

The recent improvements in multi-detector computed tomography technology and its application in cardiac field allow to consider this non-invasive imaging technique as a promising comprehensive method for detecting significant coronary stenoses in a chest-pain unit. The possibility to use the ECG-synchronisation acquisition protocol, normally limited to the cardiac volume, for the entire thoracic vascular system should have the remarkable potential to reduce invasive and non-invasive procedures actually used to investigate acute chest pain and the number of unnecessary hospital admissions without reducing appropriate admissions in patients with chest pain.