Triple Rule Out Versus Coronary CT Angiography in Patients With Acute Chest Pain

CAR and CSTR Cardiac Computed Tomography (CT) Practice Guidelines: Part 2-Non-Coronary Imaging

The cardiac computed tomography (CT) practice guidelines provide an updated review of the technological improvements since the publication of the first Canadian Association of Radiologists (CAR) cardiac CT practice guidelines in 2009. An overview of the current evidence supporting the use of cardiac CT in the most common clinical scenarios, standards of practice to optimize patient preparation and safety as well as image quality are described. Coronary CT angiography (CCTA) is the focus of Part I. In Part II, an overview of cardiac CT for non-coronary indications that include valvular and pericardial imaging, tumour and mass evaluation, pulmonary vein imaging, and imaging of congenital heart disease for diagnosis and treatment monitoring are discussed. The guidelines are intended to be relevant for community hospitals and large academic centres with established cardiac CT imaging programs.

[Benefits and drawbacks of CT scan as a triple rule-out exam in acute chest pain to exclude acute coronary syndrome, pulmonary embolism and aortic dissection]

Chest pain is one of the major causes for admission in the Emergency Room in most countries and one of the principal reasons for urgent consultation with a cardiologist or a general practitioner. After clinical examination and initial biological measurements, substantial patients require further explorations. CT scan allows the search for pulmonary embolism in the early stage of pulmonary arteries iodine contrast exploration. During the same exam at the systemic arterial phase, the search for aortic dissection or coronary artery disease is possible while exploring the later contrast in the aortic artery. This triple rule-out exam allows correct diagnosis in case of acute chest pain with suspected pulmonary embolism, aortic dissection and other acute aortic syndromes or acute coronary syndrome. But X-rays are substantially increased as well as iodine contrast agent quantity while exam quality is globally decreased. Artificial intelligence may play an important role in the development of this protocol.

Artificial intelligence-based opportunistic detection of coronary artery stenosis on aortic computed tomography angiography in emergency department patients with acute chest pain

Aims

To evaluate a deep-learning model (DLM) for detecting coronary stenoses in emergency room patients with acute chest pain (ACP) explored with electrocardiogram-gated aortic computed tomography angiography (CTA) to rule out aortic dissection.

Methods and results

This retrospective study included 217 emergency room patients (41% female, mean age 67.2 years) presenting with ACP and evaluated by aortic CTA at our institution. Computed tomography angiography was assessed by two readers, who rated the coronary arteries as 1 (no stenosis), 2 (<50% stenosis), or 3 (≥50% stenosis). Computed tomography angiography was categorized as high quality (HQ), if all three main coronary arteries were analysable and low quality (LQ) otherwise. Curvilinear coronary images were rated by a DLM using the same system. Per-patient and per-vessel analyses were conducted. One hundred and twenty-one patients had HQ and 96 LQ CTA. Sensitivity, specificity, positive predictive value, negative predictive value (NPV), and accuracy of the DLM in patients with high-quality image for detecting ≥50% stenoses were 100, 62, 59, 100, and 75% at the patient level and 98, 79, 57, 99, and 84% at the vessel level, respectively. Sensitivity was lower (79%) for detecting ≥50% stenoses at the vessel level in patients with low-quality image. Diagnostic accuracy was 84% in both groups. All 12 patients with acute coronary syndrome (ACS) and stenoses by invasive coronary angiography (ICA) were rated 3 by the DLM.

Conclusion

A DLM demonstrated high NPV for significant coronary artery stenosis in patients with ACP. All patients with ACS and stenoses by ICA were identified by the DLM.

2022 use of coronary computed tomographic angiography for patients presenting with acute chest pain to the emergency department: An expert consensus document of the Society of cardiovascular computed tomography (SCCT): Endorsed by the American College of Radiology (ACR) and North American Society for cardiovascular Imaging (NASCI)

Coronary computed tomography angiography (CTA) improves the quality of care for patients presenting with acute chest pain (ACP) to the emergency department (ED), particularly in patients with low to intermediate likelihood of acute coronary syndrome (ACS). The Society of Cardiovascular Computed Tomography Guidelines Committee was formed to develop recommendations for acquiring, interpreting, and reporting of coronary CTA to ensure appropriate, safe, and efficient use of this modality. Because of the increasing use of coronary CTA testing for the evaluation of ACP patients, the Committee has been charged with the development of the present document to assist physicians and technologists. These recommendations were produced as an educational tool for practitioners evaluating acute chest pain patients in the ED, in the interest of developing systematic standards of practice for coronary CTA based on the best available data or broad expert consensus. Due to the highly variable nature of medical care, approaches to patient selection, preparation, protocol selection, interpretation or reporting that differs from these guidelines may represent an appropriate variation based on a legitimate assessment of an individual patient's needs.

Comparison of Triple-Rule-Out Prospectively ECG-triggered Systolic and Diastolic Acquisition Protocol in Patients With Acute Chest Pain

PURPOSE

The purpose of this study was to compare image quality and coronary interpretability of triple-rule-out systolic and diastolic protocols in patients with acute chest pain.

MATERIALS AND METHODS

From March 2016 to October 2017 the authors prospectively enrolled patients with undifferentiated acute chest pain, who were at low to intermediate cardiovascular risk. Those with heart rate >75 bpm underwent a systolic prospectively triggered acquisition (systolic triggering [ST]), and in those with ≤75 bpm, end-diastolic triggering (DT) was instead performed. Examinations were evaluated for coronary artery disease, aortic dissection, and pulmonary embolism. Image quality was assessed using a Likert scale. Coronary arteries interpretability was evaluated both on a per-vessel and a per segment basis. The occurrence of major adverse cardiovascular events was investigated.

RESULTS

The final study population was 189 patients. Fifty-two patients (27.5%) underwent systolic acquisition and 137 (72.5%) underwent diastolic acquisition. No significant differences in overall image quality were observed between DT and ST groups (median score 5 [interquartile ranges 4 to 5] vs. 4 [interquartile ranges 4 to 5], P =0.074). Although both DT and ST protocols showed low percentages of noninterpretable coronary arteries on a per-vessel (1.5% and 6.7%, respectively) and per-segment analysis (1% and 4.7%, respectively), these percentages resulted significantly higher for ST groups ( P <0.001). Obstructive coronary stenosis was observed in 18 patients. Only one case of pulmonary embolism was diagnosed and no cases of aortic dissection were found in our population. No death or major adverse cardiovascular events were observed during follow-up among the 2 groups.

CONCLUSIONS

Results showed that triple-rule-out computed tomography angiography is a reliable technique in patients with acute chest pain and that an ST acquisition protocol could be considered an alternative acquisition protocol in patients with higher heart rate, reaching a good image quality.

Dedicated CCTA Followed by High-Pitch Scanning versus TRO-CT for Contrast Media and Radiation Dose Reduction: A Retrospective Study

We aimed to compare dedicated coronary computed tomography angiography (CCTA) followed by high-pitch scanning and triple-rule-out computed tomography angiography (TRO-CTA) in terms of radiation dose, contrast media (CM) use, and image quality. Patients with acute chest pain were retrospectively enrolled and assigned to group A (n = 55; scanned with dedicated CCTA followed by high-pitch scanning) or group B (n = 45; with TRO-CTA). Patient characteristics, radiation dose, CM use, and quantitative parameters (CT value, image noise, signal-to-noise ratio, contrast-to-noise ratio, and image quality score) of pulmonary arteries (PAs), thoracic aortae (TAs), and coronary arteries (CAs) were compared. The total effective dose was significantly lower in group A (6.25 ± 2.94 mSv) than B (8.93 ± 4.08 mSv; p < 0.001). CM volume was significantly lower in group A (75.7 ± 8.9 mL) than B (95.0 ± 0 mL; p < 0.001). PA and TA image quality were significantly better in group B, whereas that of CA was significantly better in group A. Qualitative image scores of PA and TA scans rated by radiologists were similar, whereas that of CA scans was significantly higher in group A than B (p < 0.001). Dedicated CCTA followed by high-pitch scanning demonstrated lower radiation doses and CM volume without debasing qualities of PA, TA, and CA scans than did TRO-CTA.

Appropriateness criteria for the use of cardiac computed tomography, SIC-SIRM part 2: acute chest pain evaluation; stent and coronary artery bypass graft patency evaluation; planning of coronary revascularization and transcatheter valve procedures; cardiomyopathies, electrophysiological applications, cardiac masses, cardio-oncology and pericardial diseases evaluation

In the past 20 years, cardiac computed tomography (CCT) has become a pivotal technique for the noninvasive diagnostic workup of coronary and cardiac diseases. Continuous technical and methodological improvements, combined with fast growing scientific evidence, have progressively expanded the clinical role of CCT. Randomized clinical trials documented the value of CCT in increasing the cost-effectiveness of the management of patients with acute chest pain presenting in the emergency department, also during the pandemic. Beyond the evaluation of stents and surgical graft patency, the anatomical and functional coronary imaging have the potential to guide treatment decision-making and planning for complex left main and three-vessel coronary disease. Furthermore, there has been an increasing demand to use CCT for preinterventional planning in minimally invasive procedures, such as transcatheter valve implantation and mitral valve repair. Yet, the use of CCT as a roadmap for tailored electrophysiological procedures has gained increasing importance to assure maximum success. In the meantime, innovations and advanced postprocessing tools have generated new potential applications of CCT from the simple coronary anatomy to the complete assessment of structural, functional and pathophysiological biomarkers of cardiac disease. In this complex and revolutionary scenario, it is urgently needed to provide an updated guide for the appropriate use of CCT in different clinical settings. This manuscript, endorsed by the Italian Society of Cardiology (SIC) and the Italian Society of Medical and Interventional Radiology (SIRM), represents the second of two consensus documents collecting the expert opinion of cardiologists and radiologists about current appropriate use of CCT.

Role of Coronary CT Angiography in the Evaluation of Acute Chest Pain and Suspected or Confirmed Acute Coronary Syndrome

Advances in CT technology have resulted in improved imaging of the coronary anatomy in patients with stable coronary artery disease, using coronary CT angiography (CCTA). Recent data suggest that CCTA may play a role in higher risk patients, such as those evaluated in the emergency room with acute chest pain. Data thus far support the use of CCTA in low-risk patients with acute chest pain. Recent literature suggests that CCTA may play a role in the risk stratification of selected intermediate-risk patients. In this review, the authors discuss the emerging role of CCTA in higher risk patients, such as those with suspected or confirmed acute coronary syndrome (ACS). The excellent accuracy of CCTA in detecting obstructive coronary artery disease in patients with ACS is detailed, along with a highlighting of the safety of using CCTA in this setting. The authors also discuss the role for CCTA atheromatous plaque characterization, which is being increasingly recognized as an important predictor of clinical outcomes.

Clinical applications of cardiac computed tomography: a consensus paper of the European Association of Cardiovascular Imaging-part II

Cardiac computed tomography (CT) was initially developed as a non-invasive diagnostic tool to detect and quantify coronary stenosis. Thanks to the rapid technological development, cardiac CT has become a comprehensive imaging modality which offers anatomical and functional information to guide patient management. This is the second of two complementary documents endorsed by the European Association of Cardiovascular Imaging aiming to give updated indications on the appropriate use of cardiac CT in different clinical scenarios. In this article, emerging CT technologies and biomarkers, such as CT-derived fractional flow reserve, perfusion imaging, and pericoronary adipose tissue attenuation, are described. In addition, the role of cardiac CT in the evaluation of atherosclerotic plaque, cardiomyopathies, structural heart disease, and congenital heart disease is revised.

Double rule-out technique for evaluation of acute chest pain using 128-row multidetector CT

AIM

To evaluate the feasibility and image quality of the double rule-out (DRO) technique using 128-row multidetector computed tomography (CT) for simultaneous evaluation of the aorta and coronary arteries in patients with acute non-specific chest pain.

MATERIALS AND METHODS

Sixty-eight patients underwent electrocardiography (ECG)-gated coronary CT followed by non-ECG-gated abdominal CT. The contrast-to-noise ratio and signal-to-noise ratio between the vessels and adjacent perivascular fat tissue were calculated for both the aorta and coronary arteries. Dose-length products were recorded. Two blinded readers graded the image quality of the aorta and coronary arteries on a two-point and a four-point scale, respectively. In addition, the severity of coronary stenosis was independently analysed for each coronary vessel.

RESULTS

The average attenuation was more than 350 HU for the aorta and >330 HU for the coronary arteries. The average (±standard deviation) volume of contrast media was 69.5 ± 12.5 ml. Interobserver agreement on the image quality of aortic and coronary data sets was perfect and substantial, respectively. There was almost perfect interobserver agreement for the all observations of the severity of coronary stenosis.

CONCLUSION

The DRO technique with a standard volume (approximately 70 ml) of contrast media is useful for acute chest pain evaluation in patients suspected of having acute aortic syndrome or acute coronary syndrome. It is also accurate and safe while maintaining the average CT attenuation of the aorta and coronary arteries >330 HU.

Myocardial Late Contrast Enhancement CT in Troponin-Positive Acute Chest Pain Syndrome

Background Acute chest pain with mild troponin rise and inconclusive diagnosis after clinical evaluation represents a diagnostic challenge. Triple-rule-out (TRO) CT may exclude coronary artery disease (CAD), as well as acute aortic syndrome and pulmonary embolism, but cannot help identify other causes of myocardial injury. Purpose To investigate the diagnostic value of a comprehensive CT protocol including both an angiographic and a late contrast enhancement (LCE) scan in participants with troponin-positive acute chest pain. Materials and Methods In this prospective study, consecutive patients with troponin-positive acute chest pain or anginal equivalent and inconclusive diagnosis after clinical evaluation (symptoms, markers, electrocardiography, and echocardiography) who underwent TRO CT between June 2018 and September 2020 were enrolled. TRO CT was performed to evaluate the presence of obstructive CAD (stenosis ≥50%), acute aortic syndrome, and pulmonary embolism. If the findings on the TRO CT scan were negative, an LCE CT scan was acquired after 10 minutes to assess the presence and pattern of scar and quantify the myocardial extracellular volume fraction. CT-based diagnoses were compared with diagnoses obtained with reference standard methods, including invasive coronary angiography, cardiac MRI, and endomyocardial biopsy. Results Eighty-four patients (median age, 69 years [interquartile range, 50-77 years]; 45 men) were enrolled. TRO CT helped identify obstructive CAD in 35 participants (42%), acute aortic syndrome in one (1.2%), and pulmonary embolism in six (7.1%). LCE CT scans were acquired in the remaining 42 participants. The following diagnoses were reached with use of LCE CT: myocarditis (22 of 42 participants [52%]), takotsubo cardiomyopathy (four of 42 [10%]), amyloidosis (three of 42 [7.1%]), myocardial infarction with nonobstructed coronary arteries (three of 42 [7.1%]), dilated cardiomyopathy (two of 42 [4.8%]), and negative or inconclusive findings (eight of 42 [19%]). The addition of LCE CT improved the diagnostic rate of TRO CT from 42 of 84 participants (50% [95% CI: 38.9, 61.1]) to 76 of 84 (90% [95% CI: 82.1, 95.8]) (P < .001). Conclusion A CT protocol including triple-rule-out and late contrast enhancement CT scans improved diagnostic rate in participants presenting with acute chest pain syndrome. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Nagpal and Bluemke in this issue.

Pulmonary embolism and computed tomography angiography: Characteristic findings and technical advices

Pulmonary embolism (PE) is a condition due to blood clots obstructing pulmonary arteries, often related to deep venous thrombosis (DVT). PE can be responsible for acute and even life-threatening clinical situations and it may also lead to chronic sequelae such as chronic thromboembolic pulmonary hypertension (CTEPH). Signs and symptoms associated to PE may overlap those of many other diseases (e.g. chest pain, dyspnea, etc.), therefore an accurate clinical evaluation is mandatory before referring the patient to the most appropriate imaging technique. Pulmonary angiography (PA) has been traditionally considered the gold standard regarding the diagnosis of PE and it is also useful regarding the treatment of said condition. However, PA is an invasive technique, implying all the known risks concerning endovascular procedures. Nowadays, computed tomography angiography (CTA) is considered the imaging technique of choice regarding the diagnosis of PE. This technique is readily-available in most centers and it is able to provide high resolution images, although it implies the administration of ionizing radiations and iodinated contrast medium. Conventional CTA has further been improved with the use of ECG-gated protocols, aimed to reduce motion artifacts due to heartbeat and to evaluate other causes of sudden onset chest pain. Moreover, another interesting technique is dual energy computed tomography (DECT), which allows to elaborate iodine maps, allowing to detect areas of hypoperfusion due to the presence of emboli in pulmonary arteries. This review is aimed to describe the main findings related to PE with an emphasis on CTA, also discussing technical aspects concerning image acquisition protocol.

Cardiac computed tomography in cardio-oncology: an update on recent clinical applications

Chemotherapy and radiotherapy have drastically improved cancer survival, but they can result in significant short- and long-term cardiovascular complications, most commonly heart failure from chemotherapy, whilst radiotherapy increases the risk of premature coronary artery disease (CAD), valve, and pericardial diseases. Cardiac computed tomography (CT) with calcium scoring has a role in screening asymptomatic patients for premature CAD, cardiac CT angiography (CTCA) allows the identification of significant CAD, also in the acute settings where concerns exist towards invasive angiography. CTCA integrates the diagnostic work-up and guides surgical/percutaneous management of valvular heart diseases and allows the assessment of pericardial conditions, including detection of effusion and pericardial calcification. It is a widely available and fast imaging modality that allows a one-step evaluation of CAD, myocardial, valvular, and pericardial disease. This review aims to provide an update on its current use and accompanying evidence-base for cardiac CT in the management of cardio-oncology patients.

Screening of Potential Cardiac Involvement in Competitive Athletes Recovering From COVID-19: An Expert Consensus Statement

As our understanding of the complications of coronavirus disease-2019 (COVID-19) evolve, subclinical cardiac pathology such as myocarditis, pericarditis, and right ventricular dysfunction in the absence of significant clinical symptoms represents a concern. The potential implications of these findings in athletes are significant given the concern that exercise, during the acute phase of viral myocarditis, may exacerbate myocardial injury and precipitate malignant ventricular arrhythmias. Such concerns have led to the development and publication of expert consensus documents aimed at providing guidance for the evaluation of athletes after contracting COVID-19 in order to permit safe return to play. Cardiac imaging is at the center of these evaluations. This review seeks to evaluate the current evidence regarding COVID-19-associated cardiovascular disease and how multimodality imaging may be useful in the screening and clinical evaluation of athletes with suspected cardiovascular complications of infection. Guidance is provided with diagnostic "red flags" that raise the suspicion of pathology. Specific emphasis is placed on the unique challenges posed in distinguishing athletic cardiac remodeling from subclinical cardiac disease. The strengths and limitations of different imaging modalities are discussed and an approach to return to play decision making for athletes post-COVID-19, as informed by multimodality imaging, is provided.

ACR Appropriateness Criteria® Acute Nonspecific Chest Pain-Low Probability of Coronary Artery Disease

Patients with acute nonspecific chest pain and low probability for coronary disease remain an important clinical management dilemma. We focus on evidence for imaging, in an integrated decision-making setting. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Coronary computed tomography angiography (CCTA): effect of bolus-tracking ROI positioning on image quality

Objectives

The aim of the study was to evaluate the effect of bolus-tracking ROI positioning on coronary computed tomography angiography (CCTA) image quality.

Methods

In this retrospective monocentric study, all patients had undergone CCTA by step-and-shoot mode to rule out coronary artery disease within a cohort at intermediate risk. Two groups were formed, depending on ROI positioning (left atrium (LA) or ascending aorta (AA)). Each group contained 96 patients. To select pairs of patients, propensity score matching was used. Image quality with regard to coronary arteries as well as pulmonary arteries was evaluated using quantitative and qualitative scores.

Results

In terms of the coronary arteries, there was no significant difference between both groups using quantitative (SNR AA 14.92 vs. 15.46; p = 0.619 | SNR LM 19.80 vs. 20.30; p = 0.661 | SNR RCA 24.34 vs. 24.30; p = 0.767) or qualitative scores (4.25 vs. 4.29; p = 0.672), respectively. With regard to pulmonary arteries, we found significantly higher quantitative (SNR RPA 8.70 vs. 5.89; p < 0.001 | SNR LPA 9.06 vs. 6.25; p < 0.001) and qualitative scores (3.97 vs. 2.24; p < 0.001) for ROI positioning in the LA than for ROI positioning in the AA.

Conclusions

ROI positioning in the LA or the AA results in comparable image quality of CT coronary arteriography, while positioning in the LA leads to significantly higher image quality of the pulmonary arteries. These results support ROI positioning in the LA, which also facilitates triple-rule-out CT scanning.

Key Points

• ROI positioning in the left atrium or the ascending aorta leads to comparable image quality of the coronary arteries.

• ROI positioning in the left atrium results in significantly higher image quality of the pulmonary arteries.

• ROI positioning in the left atrium is feasible to perform triple-rule-out CTA.

Heart and Lung Multimodality Imaging in COVID-19

The severe acute respiratory syndrome-coronavirus-2 outbreak has rapidly reached pandemic proportions and has become a major threat to global health. Although the predominant clinical feature of coronavirus disease-2019 (COVID-19) is an acute respiratory syndrome of varying severity, ranging from mild symptomatic interstitial pneumonia to acute respiratory distress syndrome, the cardiovascular system can be involved in several ways. As many as 40% of patients hospitalized with COVID-19 have histories of cardiovascular disease, and current estimates report a proportion of myocardial injury in patients with COVID-19 of up to 12%. Multiple pathways have been suggested to explain this finding and the related clinical scenarios, encompassing local and systemic inflammatory responses and oxygen supply-demand imbalance. From a clinical point of view, cardiac involvement during COVID-19 may present a wide spectrum of severity, ranging from subclinical myocardial injury to well-defined clinical entities (myocarditis, myocardial infarction, pulmonary embolism, and heart failure), whose incidence and prognostic implications are currently largely unknown because of a significant lack of imaging data. Integrated heart and lung multimodality imaging plays a central role in different clinical settings and is essential in the diagnosis, risk stratification, and management of patients with COVID-19. The aims of this review are to summarize imaging-oriented pathophysiological mechanisms of lung and cardiac involvement in COVID-19 and to provide a guide for integrated imaging assessment in these patients.

Machine learning-based CT fractional flow reserve assessment in acute chest pain: first experience

Background

Computed tomography (CT)-derived fractional flow reserve (FFR_CT) enables the non-invasive functional assessment of coronary artery stenosis. We evaluated the feasibility and potential clinical role of FFR_CT in patients presenting to the emergency department with acute chest pain who underwent chest-pain CT (CPCT).

Methods

For this retrospective IRB-approved study, we included 56 patients (median age: 62 years, 14 females) with acute chest pain who underwent CPCT and who had at least a mild (≥25% diameter) coronary artery stenosis. CPCT was evaluated for the presence of acute plaque rupture and vulnerable plaque features. FFR_CT measurements were performed using a machine learning-based software. We assessed the agreement between the results from FFR_CT and patient outcome (including results from invasive catheter angiography and from any non-invasive cardiac imaging test, final clinical diagnosis and revascularization) for a follow-up of 3 months.

Results

FFR_CT was technically feasible in 38/56 patients (68%). Eleven of the 38 patients (29%) showed acute plaque rupture in CPCT; all of them underwent immediate coronary revascularization. Of the remaining 27 patients (71%), 16 patients showed vulnerable plaque features (59%), of whom 11 (69%) were diagnosed with acute coronary syndrome (ACS) and 10 (63%) underwent coronary revascularization. In patients with vulnerable plaque features in CPCT, FFRCT had an agreement with outcome in 12/16 patients (75%). In patients without vulnerable plaque features (n=11), one patient showed myocardial ischemia (9%). In these patients, FFR_CT and patient outcome showed an agreement in 10/11 patients (91%).

Conclusions

Our preliminary data show that FFR_CT is feasible in patients with acute chest pain who undergo CPCT provided that image quality is sufficient. FFR_CT has the potential to improve patient triage by reducing further downstream testing but appears of limited value in patients with CT signs of acute plaque rupture.

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.

In-Hospital Cost Comparison of Triple-Rule-Out Computed Tomography Angiography Versus Standard of Care in Patients With Acute Chest Pain

PURPOSE

The purpose of this study was to evaluate the utilization of invasive and noninvasive tests and compare cost in patients presenting with chest pain to the emergency department (ED) who underwent either triple-rule-out computed tomography angiography (TRO-CTA) or standard of care.

MATERIALS AND METHODS

We performed a retrospective single-center analysis of 2156 ED patients who presented with acute chest pain with a negative initial troponin and electrocardiogram for myocardial injury. Patient cohorts matched by patient characteristics who had undergone TRO-CTA as a primary imaging test (n=1139) or standard of care without initial CTA imaging (n=1017) were included in the study. ED visits, utilization of tests, and costs during the initial episode of hospital care were compared.

RESULTS

No significant differences in the diagnosis of coronary artery disease, pulmonary embolism, or aortic dissection were observed. Median ED waiting time (4.5 vs. 7.0 h, P<0.001), median total length of hospital stay (5.0 vs. 32.0 h, P<0.001), hospital admission rate (12.6% vs. 54.2%, P<0.001), and ED return rate to our hospital within 30 days (3.5% vs. 14.6%, P<0.001) were significantly lower in the TRO-CTA group. Moreover, reduced rates of additional testing and invasive coronary angiography (4.9% vs. 22.7%, P<0.001), and ultimately lower total cost per patient (11,783$ vs. 19,073$, P<0.001) were observed in the TRO-CTA group.

CONCLUSIONS

TRO-CTA as an initial imaging test in ED patients presenting with acute chest pain was associated with shorter ED and hospital length of stay, fewer return visits within 30 days, and ultimately lower ED and hospitalization costs.

CAD-RADS: Pushing the Limits

Coronary CT angiography is now established as the first-line diagnostic imaging test to exclude coronary artery disease (CAD) in the population at low to intermediate risk. Wide variability exists in both the reporting of coronary CT angiography and the interpretation of these reports by referring physicians. The CAD Reporting and Data System (CAD-RADS) is sponsored by multiple societies and is a collaborative effort to provide standard classification of CAD, which is then integrated into patient clinical care. The main goals of the CAD-RADS are to decrease variability among readers; enhance communication between interpreting and referring clinicians, allowing collaborative determination of the best course of patient care; and generate consistent data for auditing, data mining, quality improvement, research, and education. There are several scenarios in which the CAD-RADS guidelines are ambiguous or do not provide definite recommendations for further management of CAD. The authors discuss the CAD-RADS categories and modifiers, highlight a variety of complex or ambiguous scenarios, and provide recommendations for managing these scenarios. Online supplemental material is available for this article. ^©RSNA, 2020 See discussion on this article by Aviram and Wolak.

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.

Diagnosis and risk stratification of chest pain patients in the emergency department: focus on acute coronary syndromes. A position paper of the Acute Cardiovascular Care Association

This paper provides an update on the European Society of Cardiology task force report on the management of chest pain. Its main purpose is to provide an update on the decision algorithms and diagnostic pathways to be used in the emergency department for the assessment and triage of patients with chest pain symptoms suggestive of acute coronary syndromes.

Incidental Non-cardiac Findings in Cardiovascular Imaging

Improvements in imaging techniques have led to an expansion in the number of cross-sectional cardiac studies being performed. This means that incidental non-cardiac findings (INCF) identified on cardiac imaging have become an important clinical concern. The majority of INCF are not clinically significant. However, some INCF will require follow-up or changes in management. Differentiating clinically significant from non-significant INCF can be challenging, particularly given the breadth of potential findings and the range of organ systems involved. Following up INCF also has economic implications. Recent changes to the lung nodule follow-up guidelines will reduce the cost of following up incidental lung nodules. In this manuscript, we discuss the common and important INCF which may be identified in cardiovascular imaging and explore potential implications of these findings.

Diagnostic Accuracy of Electrocardiogram-Gated Thoracic Computed Tomography Angiography without Heart Rate Control for Detection of Significant Coronary Artery Stenosis in Patients with Acute Ischemic Stroke: A Comparative Study

Objective

To compare the diagnostic performance of electrocardiogram (ECG)-gated thoracic computed tomography angiography (TCTA) without heart rate (HR) control in ischemic stroke patients with coronary CTA (CCTA) in non-stroke patients for detection of significant coronary artery stenosis.

Materials and Methods

From September 2009 through August 2014, we retrospectively enrolled 138 consecutive patients diagnosed with acute ischemic stroke who had undergone ECG-gated TCTA and conventional coronary angiography (CCA). Over the same period, we selected 167 non-stroke patients with suspected or known coronary artery disease who had undergone CCTA and CCA. With CCA as the reference standard, the diagnostic performance of TCTA and CCTA for identification of significant coronary stenosis (diameter reduction ≥ 50%) was calculated.

Results

There was no significant difference in baseline characteristics between TCTA (n = 132) and CCTA (n = 164), except for the higher prevalence of atrial fibrillation in the stroke group. There was significant difference (p < 0.001) between TCTA and CCTA in average HR (68 ± 12 vs. 61 ± 10 beats per minute) and image quality score (1.3 ± 0.6 vs. 1.2 ± 0.6). Significant coronary stenosis was identified in 101 (77%) patients, 179 (45%) vessels, and 293 (15%) segments of stroke patients, and in 136 (83%) patients, 259 (53%) vessels, and 404 (16%) segments of non-stroke patients. Diagnostic performance on a per-vessel and per-patient basis was similar in both TCTA and CCTA groups. There was only significant difference in area under receiver-operating characteristic curve between TCTA and CCTA groups (0.79 vs. 0.87, p < 0.001) on per-segment basis.

Conclusion

Electrocardiogram-gated TCTA without HR control facilitates the identification of significant coronary stenosis in patients with ischemic stroke.

Lex parsimoniae

We present a noteworthy case of dual pathology in a 62-year-old female with recurrent chest pains and extensive cardiac risk factors. From computed tomography coronary angiography, a left anterior descending artery lesion was identified and successfully revascularized with a drug-eluting stent. Due to persistent chest pain, further investigation revealed a descending aortic dissection, which was conservatively managed. This case highlights the potential challenges of diagnosis in dual pathologies and emphasizes initiating appropriate investigations. <Learning objectives: It is important to consider all differential diagnoses in atypical presentations of possible acute coronary syndrome. As clinical presentations and risk factors may be similar, initiating appropriate diagnostic and management pathways are crucial to avoid misdiagnosis.>.

The role of MRI and CT for diagnosis and work-up in suspected ACS

This article describes the role of cardiovascular magnetic resonance (CMR) and cardiac computed tomography (CCT) in the diagnostic work-up of patients with suspected acute coronary syndrome (ACS). Recent studies on the principles, diagnostic targets, clinical utility, accuracy, prognostic relevance and implications for clinical decision-making are discussed and current state-of-the-art and novel approaches are presented. The authors recognize that in ACS, time is of the essence and therefore put a special emphasis on the feasibility of tomographic cardiac imaging in realistic clinical settings.

The role of cardiac CT in women

Due to the discrepancy between higher symptom burden and lower disease prevalence, the diagnosis of coronary artery disease (CAD) in women is challenging. Cardiac CT can be particularly useful in CAD diagnosis and risk stratification in women. In this review, we explore cardiac CT in women with and without symptoms and for adjudication of functional tests. Novel CT technologies such as fractional flow reserve and stress perfusion imaging and their potential for usefulness in women are also examined.

Assessment of myocardial enhancement during coronary CT angiography in critically ill patients

There are still challenges and unmet needs for the imaging techniques, such as conditions of uncertain origin in patients with clinically serious, life-threatening conditions with unknown cause that are not associated with dominant chest pain, ECG changes or other symptoms indicating a possible primarily cardiac or coronary cause. The contribution of the myocardial enhancement evaluation of urgent cardiac CTA scans significantly improves to determining the diagnosis of acute myocardial injury and choosing appropriate treatment. When incorporating the myocardial enhancement assessment into the imaging algorithm of an emergency department, emphasis is placed on a uniform imaging procedure and a uniform evaluation approach. The color coded images of the myocardial enhancement in emergency situations helps identify the most serious pathologies and shorten the time to adequate targeted therapy in patients.

Acute chest pain in the high-sensitivity cardiac troponin era: A changing role for noninvasive imaging?

Management of patients with acute chest pain remains challenging. Cardiac biomarker testing reduces the likelihood of erroneously discharging patients with acute myocardial infarction (AMI). Despite normal contemporary troponins, physicians have still been reluctant to discharge patients without additional testing. Nowadays, the extremely high negative predictive value of current high-sensitivity cardiac troponin (hs-cTn) assays challenges this need. However, the decreased specificity of hs-cTn assays to diagnose AMI poses a new problem as noncoronary diseases (eg, pulmonary embolism, myocarditis, cardiomyopathies, hypertension, renal failure, etc) may also cause elevated hs-cTn levels. Subjecting patients with noncoronary diseases to unnecessary pharmacological therapy or invasive procedures must be prevented. Attempts to improve the positive predictive value to diagnose AMI by defining higher initial cutoff values or dynamic changes over time inherently lower the sensitivity of troponin assays. In this review, we anticipate a potential changing role of noninvasive imaging from ruling out myocardial disease when troponin values are normal toward characterizing myocardial disease when hs-cTn values are (mildly) abnormal.

Triple rule-out computed tomography for risk stratification of patients with acute chest pain

AIMS

Clinical evidence supporting triple rule-out computed tomography (TRO-CT) for rapid screening of cardiovascular disease is limited. We investigated the clinical value of TRO-CT in patients with acute chest pain.

METHODS

We retrospectively enrolled 1024 patients who visited the emergency department (ED) with acute chest pain and underwent TRO-CT using a 128-slice CT system. TRO-CT was classified as "positive" if it revealed clinically significant cardiovascular disease including obstructive coronary artery disease, pulmonary thromboembolism, or acute aortic syndrome. The clinical endpoint was occurrence of a major adverse cardiovascular event (MACE) within 30 days, defined by a composite of all cause death, myocardial infarction, revascularization, major cardiovascular surgery, or thrombolytic therapy. Clinical risk scores for acute chest pain including TIMI, GRACE, Diamond-Forrester, and HEART were determined and compared to the TRO-CT findings.

RESULTS

TRO-CT revealed clinically significant cardiovascular disease in 239 patients (23.3%). MACE occurred in 119 patients (49.8%) with positive TRO-CT and in 7 patients (0.9%) with negative TRO-CT (p < 0.001). Sensitivity, specificity, positive predictive value, and negative predictive value of TRO-CT was 95%, 88%, 54%, and 99%, respectively. TRO-CT was a better discriminator between patients with vs. without events as compared to clinical risk scores (c-statistics = 0.91 versus 0.64 to 0.71; integrated discrimination improvement = 0.31 to 0.37; p < 0.001 for all comparisons). Patients with a negative TRO-CT showed shorter ED stay times and admission rates compared to patients with positive TRO-CT, irrespective of clinical risk scores (p < 0.001 for all comparisons).

CONCLUSION

Triple rule-out CT has high predictive performance for 30-day MACE and permits rapid triage and low admission rates irrespective of clinical risk scores.

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.

Chest pain: coronary CT in the ER

Cardiac CT has developed into a robust clinical tool during the past 15 years. Of the fields in which the potential of cardiac CT has raised more interest is chest pain in acute settings. In fact, the possibility to exclude with high reliability obstructive coronary artery disease (CAD) in patients at low-to-intermediate risk is of great interest both from the clinical standpoint and from the management standpoint. Several other modalities, with or without imaging, have been used during the past decades in the settings of new onset chest pain or in acute chest pain for both diagnostic and prognostic assessment of CAD. Each one has advantages and disadvantages. Most imaging modalities also focus on inducible ischaemia to guide referral to invasive coronary angiography. The advent of cardiac CT has introduced a new practice diagnostic paradigm, being the most accurate non-invasive method for identification and exclusion of CAD. Furthermore, the detection of subclinical CAD and plaque imaging offer the opportunity to improve risk stratification. Moreover, recent advances of the latest generation CT scanners allow combining both anatomical and functional imaging by stress myocardial perfusion. The role of cardiac CT in acute settings is already important and will become progressively more important in the coming years.