Usefulness of 64-slice cardiac computed tomographic angiography for diagnosing acute coronary syndromes and predicting clinical outcome in emergency department patients with chest pain of uncertain origin

[Why Coronary CTA will affect the diagnosis and management of stable coronary artery disease?]

Until recently, the optimal work-up of patients with stable coronary artery disease (CAD) was based on non-invasive functional tests. Coronary CTA (CCTA) now challenges this standard work-up due to its efficacy to exclude significant coronary artery disease. Current indications for CCTA include symptomatic patients with intermediate pre-test probability of CAD with altered ECG (LBBB, repolarization abnormalities) rendering stress tests useless or patients unable to achieve sustained stress effort, and patients with indeterminate or uninterpretable results on ischemic work-up. A more agressive position is to consider CCTA as the cornerstone of patient management because the limitations and pitfalls of non-invasive techniques open the door to an alternative diagnostic imaging technique, either alone, or in combination with other Imaging techniques after reorganizing the sequence of imaging work-up. Without dismissing the dogma of initial détection of CAD along with prognostic stratification using functional tests, the recent availability of a minimally invasive anatomical test in the management of patients with stress angina, given the known limitations of traditional tests, changes the standard work-up algorithms. This suggests that the diagnostic work-up of patients with CAD is likely to be modified to increase the rôle of CCTA.

Radiation dose in a "triple rule-out" coronary CT angiography protocol of emergency department patients using 64-MDCT: the impact of ECG-based tube current modulation on age, sex, and body mass index

OBJECTIVE

"Triple rule-out" coronary CT angiography (CTA) using 64-MDCT technology is a new approach for evaluating emergency department patients presenting with symptoms suggestive of acute coronary syndrome (ACS). Our objective was to evaluate the reduction in effective radiation dose through the use of tube current modulation in patients who underwent a triple rule-out coronary CTA evaluation and to document how effective radiation dose was impacted by patient age, sex, and body mass index (BMI).

MATERIALS AND METHODS

A retrospective analysis of triple rule-out coronary CTA examinations performed on a 64-MDCT scanner was ordered on a prospective cohort of 267 consecutive low- to moderate-risk emergency department patients with suspected ACS from a single university hospital between October 2006 and March 2008. Tube current modulation was generally used in patients with heart rates below 65 beats per minute during the second half of the study period as a way to reduce radiation exposure. We calculated effective radiation exposure using actual patient coronary CTA scanning parameters by age, sex, and BMI.

RESULTS

Among the 172 patients evaluated without tube current modulation, effective dose averaged (+/- SD) 18.0 +/- 5.6 mSv (range, 9.9-31.3 mSv). Of the 95 patients who underwent CTA examination with tube current modulation, effective dose was significantly lower at 8.75 +/- 2.64 mSv (range, 5.4-16.6 mSv; p < 0.0001) and image quality was better (p < 0.0001) as compared with examinations without tube current modulation. There were no significant radiation differences by patient age, but tube current modulation decreased radiation exposure by at least half. Among the studies in which tube current modulation was not used, women received less radiation than men (17.0 vs 19.5 mSv, respectively; p < 0.001). For the studies with tube current modulation, there were no radiation differences by sex. Obese patients received significantly more radiation than overweight and normal-weight patients in the non-tube current modulation groups (20.9 mSv vs 15.0 and 14.9 mSv, respectively; p < 0.0001) and in the tube current modulation groups (10.3 mSv vs 7.6 and 7.1 mSv, p < 0.0001).

CONCLUSION

The overall effective radiation dose for triple rule-out coronary CTA was reduced by more than 50% with ECG-based tube current modulation without loss of image quality. Tube current modulation should be used for triple rule-out coronary CTA examinations whenever possible.

Value of multidetector computed tomography evaluation of myocardial perfusion in the assessment of ischemic heart disease: comparison with nuclear perfusion imaging

MDCT-derived myocardial perfusion has not yet been validated against accepted standards. We developed a technique for quantification of myocardial perfusion from MDCT images and studied its diagnostic value against SPECT myocardial perfusion imaging (MPI). Ninety-eight patients were studied. Abnormal perfusion was detected by comparing normalized segmental x-ray attenuation against values obtained in 20 control subjects. Disagreement with resting MPI was investigated in relationship to MDCT image quality, severity of MPI abnormalities, and stress MPI findings. Resting MPI detected mild or worse abnormalities in 20/78 patients. MDCT detected abnormalities in 15/20 patients (sensitivity of 0.75). Most abnormalities missed by MDCT analysis were graded as mild on MPI. Additional abnormalities found in 16/78 patients were not confirmed on resting MPI (specificity of 0.72). However, 8 of these 16 apparently false positive MDCT perfusion tests had abnormal stress MPI; of these 8 patients, 7 had optimal MDCT image quality, while in 6/8 remaining patients, image quality was suboptimal. When compared with resting MPI, MDCT detected perfusion abnormalities with high accuracy. Moreover, half of MDCT perfusion abnormalities not confirmed by resting MPI were associated with abnormal stress MPI. Importantly, this information can be obtained without additional radiation dose or contrast agent.

Limitations of risk score models in patients with acute chest pain

OBJECTIVES

Cardiac multidetector computed tomography (CMCT) has potential to be used as a screening test for patients with acute chest pain, but several tools are already used to risk-stratify this population. Risk models exist that stratify need for intensive care (Goldman), short-term prognosis (Thrombolysis in Myocardial Infarction, TIMI), and 1-year events (Sanchis). We applied these cardiovascular risk models to candidates for CMCT and assessed sensitivity for prediction of in-hospital acute coronary syndrome (ACS). We hypothesized that none of the models would achieve a sensitivity of 90% or greater, thereby justifying use of CMCT in patients with acute chest pain.

METHODS

We analyzed TIMI, Goldman, and Sanchis in 148 consecutive patients with chest pain, nondiagnostic electrocardiogram, and negative initial cardiac biomarkers who previously met inclusion and exclusion criteria for the Rule-Out Myocardial Infarction Using Coronary Artery Tomography Study. ACS was adjudicated, and risk scores were categorized based on established criteria. Risk score agreement was assessed with weighted kappa statistics.

RESULTS

Overall, 17 (11%) of 148 patients had ACS. For all risk models, sensitivity was poor (range, 35%-53%), and 95% confidence intervals did not cross above 77%. Agreement to risk-classify patients was poor to moderate (weighted kappa range, 0.18-0.43). Patients categorized as "low risk" had nonzero rates of ACS using all 3 scoring models (range, 8%-9%).

CONCLUSIONS

Available risk scores had poor sensitivity to detect ACS in patients with acute chest pain. Because of the small number of patients in this data set, these findings require confirmation in larger studies.

Cardiac multi-detector CT: its unique contribution to cardiology practice

Medical practice is moving fast towards non-invasive and non-surgical disease management. While significant progress has been made with coronary artery disease prevention, MDCT stands as an ideal non-invasive tool for its progression. It accurately assesses both arterial lumen and wall disease. Although the main concern of current cardiology practice is the coronary stenotic disease, arterial wall calcification itself may significantly contribute to patients' symptoms. Thus, in addition to the beneficial use of MDCT in patients with mild to moderate risk for coronary disease, the unique information it provides on wall disease may assist the management of symptomatic patients with no flow-limiting lesions.

Cardiovascular risk in women with non-specific chest pain (from the Women's Health Initiative Hormone Trials)

Women discharged with diagnoses of nonspecific chest pain (NSCP) may be at increased risk for subsequent coronary artery disease (CAD) events. The influence of hormone therapy on NSCP is unknown. The Women's Health Initiative (WHI) enrolled postmenopausal women aged 50 to 79 years. The duration of follow-up was 7.1 years in the WHI Estrogen-Alone trial (E-Alone) and 5.6 years in the WHI Estrogen Plus Progestin trial (E+P). After excluding women with previous cardiovascular disease, 9,427 women in E-Alone and 15,105 women in E+P were included in this analysis. NSCP, defined as having a primary hospital discharge diagnosis of NSCP by International Classification of Diseases, Ninth Revision, code, was reported in 322 women in E-Alone and 249 in E+P. Risks for subsequent CAD events were estimated using intent-to-treat Cox proportional-hazards models stratified by clinic and adjusted for age and other risk factors. In the fully adjusted models of the combined trials, women with NSCP had a twofold greater risk for subsequent nonfatal CAD events, including nonfatal myocardial infarction (2.3% vs 1.7%, hazard ratio [HR] 2.10, 95% confidence interval [CI] 1.11 to 3.98), revascularization (3.5% vs 2.6%, HR 1.99, 95% CI 1.20 to 3.30), and hospitalized angina (3.7% vs 2.3%, HR 2.39, 95% CI 1.46 to 3.92). Hormone therapy did not appear to have a significant effect on either the incidence of NSCP hospitalizations (E-Alone: HR 1.04, 95% CI 0.81 to 1.32; E+P: HR 0.78, 95% CI 0.59 to 1.02) or the risk for a subsequent CAD event. In conclusion, a hospitalization for NSCP doubles the risk for a subsequent CAD event in postmenopausal women over the next 5 to 7 years and identifies them as candidates for aggressive risk factor treatment.

Noninvasive evaluation with multislice computed tomography in suspected acute coronary syndrome: plaque morphology on multislice computed tomography versus coronary calcium score

OBJECTIVES

Our aim was to evaluate the atherosclerotic plaque burden and morphology as determined by 64-slice multislice computed tomography (MSCT) coronary angiography in relation to the calcium score in patients presenting with suspected acute coronary syndrome (ACS).

BACKGROUND

The absence of coronary calcium during coronary calcium scoring has been proposed to rule out significant coronary artery disease (CAD). However, data in patients presenting with suspected ACS are scarce.

METHODS

In 40 patients (age 57 +/- 11 years, 26 men) presenting with suspected ACS, MSCT coronary angiography in combination with coronary calcium scoring was performed before conventional coronary angiography. MSCT angiograms were evaluated for the presence or absence of coronary atherosclerotic plaque and the presence or absence of obstructive (> or =50% luminal narrowing) CAD. In addition, plaque type was determined, and findings were related to the calcium score.

RESULTS

Coronary artery disease was observed in 38 patients, of whom 10 patients had nonobstructive and 28 patients had obstructive CAD, confirmed by conventional coronary angiography in all patients. In patients with CAD, plaques were distributed as follows: 39% noncalcified plaques, 47% mixed plaques, and 14% calcified plaques. Coronary calcium was detected in 27 patients, of whom 10 had a score >400. In 13 (33%) patients, no coronary calcium was observed, but in 11 (85%), atherosclerotic plaques were detected on MSCT angiography.

CONCLUSIONS

In patients presenting with suspected ACS, noncalcified plaques are highly prevalent and the absence of coronary calcium does not reliably exclude the presence of (significant) atherosclerosis. This information may be of value to improve our understanding of the potential role of MSCT in this patient population.

Emergency department imaging: current practice

PURPOSE

To provide a snapshot of the demographics of radiologists providing coverage for emergency departments (EDs) and current imaging practices in EDs in the United States.

METHODS

An online survey was created with Views Flash 3 software (Cogix, Monterey, California). Random e-mail addresses from a variety of databases were chosen. A total of 678 surveys were sent over a 9-month period.

RESULTS

One hundred ninety-two radiology groups (28%) responded to the survey. Forty-one groups (21%) had designated emergency radiology divisions. Sixty-three groups (33%) were using computed tomographic (CT) coronary angiography in the ED workup of chest-pain. Thirty-five groups (18%) were using "triple-rule-out scans" (ie, a single CT scan to rule out coronary artery disease, pulmonary embolism, and aortic dissection). Multiplanar reconstructions of chest, abdominal, and pelvic CT images were routinely performed by 95 groups (49%). Forty-four percent used reformatted CT images instead of conventional radiographs in the workup of cervical spine trauma, and 68 groups (35%) used reformations in thoracic and lumbar spine trauma. Ninety groups (47%) did not use oral contrast for blunt abdominal trauma CT scanning. Sixty-seven respondents (35%) preferred computed tomography to evaluate for acute appendicitis in the setting of pregnancy. Forty percent of imaging equipment located within the EDs was CT scanners. The majority of the groups still communicated unexpected findings via telephone (49%).

CONCLUSION

New imaging practices for the evaluation of entities such as chest pain, spine trauma, and abdominal pain and trauma are emerging in EDs. As one plans ED development, these trends should be considered.

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.

Cardiac magnetic resonance with T2-weighted imaging improves detection of patients with acute coronary syndrome in the emergency department

BACKGROUND

Cardiac magnetic resonance (CMR) imaging permits early triage of patients presenting to the emergency department with acute chest pain but has been limited by the inability to differentiate new from old myocardial infarction. Our objective was to evaluate a CMR protocol that includes T2-weighted imaging and assessment of left ventricular wall thickness in detecting patients with acute coronary syndrome in the emergency department.

METHODS AND RESULTS

In this prospective cohort observational study, we enrolled patients presenting to the emergency department with acute chest pain, negative cardiac biomarkers, and no ECG changes indicative of acute ischemia. The CMR protocol consisted of T2-weighted imaging, first-pass perfusion, cine function, delayed-enhancement magnetic resonance imaging, and assessment of left ventricular wall thickness. The clinical outcome (acute coronary syndrome) was defined by review of clinical charts by a consensus panel that used American Heart Association/American College of Cardiology guidelines. Among 62 patients, 13 developed acute coronary syndrome during the index hospitalization. The mean CMR time was 32+/-8 minutes. The new CMR protocol (with the addition of T2-weighted and left ventricular wall thickness) increased the specificity, positive predictive value, and overall accuracy from 84% to 96%, 55% to 85%, and 84% to 93%, respectively, compared with the conventional CMR protocol (cine, perfusion, and delayed-enhancement magnetic resonance imaging). Moreover, in a logistic regression analysis that contained information on clinical risk assessment (c-statistic=0.695) and traditional cardiac risk factors (c-statistic=0.771), the new CMR protocol significantly improved the c-statistic to 0.958 (P<0.0001).

CONCLUSIONS

The present study indicates that a new CMR protocol improves the detection of patients with acute coronary syndrome in the emergency department and adds significant value over clinical assessment and traditional cardiac risk factors.

Usefulness of 64-slice multidetector computed tomography as an initial diagnostic approach in patients with acute chest pain

BACKGROUND

Recently, multidetector computed tomography (MDCT) has been proposed as an accurate diagnostic tool to evaluate for coronary artery disease. However, the role of MDCT as part of the initial diagnostic for evaluating acute chest pain is less well established.

METHODS

We prospectively enrolled patients presenting with acute chest pain to the emergency department (ED) and risk stratified them based on the pretest probability for an acute coronary syndrome (ACS): (1) very low, (2) low, (3) intermediate, (4) high, and (5) very high or definite. After exclusion of very low and very high risk patients, 268 patients were randomized to either immediate 64-slice cardiac MDCT or a conventional diagnostic strategy. Number of admissions, ED and hospital length of stay (LOS), and major adverse cardiac events over 30 days of follow-up were compared between the strategies based on the pretest probability for ACS.

RESULTS

The number of patients ultimately diagnosed with an ACS did not differ between the 2 strategies. Emergency department LOS and total admissions were not different between strategies. Patients in the MDCT-based strategy had a decreased hospital LOS (P = .049) and fewer admissions deemed unnecessary (P = .007). Reductions in unnecessary admissions were more prominent in intermediate-risk patients (P = .015). None of the patients discharged from the ED in the MDCT-based strategy experienced major adverse cardiac events at follow-up.

CONCLUSION

Use of an MDCT-based strategy in the ED as part of the initial diagnostic approach for patients presenting with acute chest pain is safe and efficiently reduces avoidable admissions in patients with an intermediate pretest probability for ACS.

Actual financial comparison of four strategies to evaluate patients with potential acute coronary syndromes

OBJECTIVES

Small studies have shown that a negative computed tomography coronary angiogram (CTA) in low-risk chest pain patients predicts a low rate of 30-day adverse events. The authors hypothesized that an immediate CTA strategy would be as effective but less costly than alternative strategies for evaluation of patients with potential acute coronary syndrome (ACS).

METHODS

The authors retrospectively compared four strategies for evaluation of patients after initial physician determination that the patient required admission and testing to rule out ACS. Patients were frequency-matched by age, race, gender, thrombolysis in myocardial infarction (TIMI) score, and initial electrocardiogram (ECG). The four groups were immediate CTA in the emergency department (ED) without serial markers (n = 98); clinical decision unit/observation unit (CDU) with biomarkers and CTA (n = 102); CDU evaluation with serial cardiac biomarkers and stress testing (n = 154); and usual care, defined as admission with serial biomarkers and hospitalist-directed evaluation (n = 289). The main outcomes were actual cost of care (facility direct and indirect fixed, facility variable direct labor and supply costs), length of stay (LOS), diagnosis of coronary artery disease (CAD), and safety (30-day death or myocardial infarction [MII).

RESULTS

Patients in each group were of similar age (mean +/- standard deviation [SD] 46 +/- 9 years), race (62% African American), and gender (57% female) and had similar TIMI scores (100% between 0-2). Comparing immediate CTA versus CDU CTA versus CDU stress versus usual care, median costs were less ($1,240 vs. 2,318 vs. 4,024 vs. 2,913; p < 0.01), and LOS was shorter (8.1 hr vs. 20.9 hr vs. 26.2 hr vs. 30.2 hr; p < 0.01). Diagnosis of CAD was similar (5.1% vs. 5.9% vs. 5.8% vs. 6.6%; p = 0.95), but fewer patients had 30-day death/MI (0% vs. 0% vs. 0.7% vs. 3.1%; p = 0.04) or 30-day readmission (0% vs. 3.2% vs. 2.3% vs. 12.2%; p < 0.01).

CONCLUSIONS

Compared to the other strategies, immediate CTA was as safe, identified as many patients with CAD, had the lowest cost, had the shortest LOS, and allowed discharge for the majority of patients. Larger prospective studies should confirm safety before immediate CTA replaces other strategies to rule out possible ACS.

Coronary computed tomography angiography---a promising imaging modality in diagnosing coronary artery disease

BACKGROUND

Traditionally, information on coronary artery lesions is obtained from invasive coronary angiography (CAG). The clinical applicability and diagnostic performance of the newly developed 64-slice multislice computed tomography (MSCT) scanner in coronary angiographic evaluation is not well evaluated.

METHODS

Coronary computed tomography angiography (CCTA) was performed in 345 patients (119 women, 226 men; mean age, 59.64 +/- 11.67 years). Concomitant CAG was performed in 53 patients. The diagnostic performance of CCTA for detecting significant lesions was compared with that of CAG by 3 independent cardiologists.

RESULTS

All CCTA was performed without complication. Comparison between CCTA and CAG was made in the 53 patients who underwent both studies. Sensitivity, specificity and the positive and negative predictive values for the 53 patients were: 81%, 99%, 87% and 99%, respectively.

CONCLUSION

The 64-slice MSCT, developed in recent years, allows reliable noninvasive evaluation of coronary artery morphology, including plaque, stenosis and congenital anomaly. The diagnostic accuracy of MSCT scans for detecting lesions makes it a good imaging substitute for CAG in the evaluation of these coronary segments.

CT and MRI of acute thoracic cardiovascular emergencies

A wide spectrum of acute cardiovascular disorders is seen in patients who are hospitalized in a critical care setting. Imaging plays a central role in the diagnosis and management of these conditions. The most frequently used imaging remains chest radiography; however, more advanced modalities, including coronary angiography, echocardiography, and radioisotope scintigraphy, have well established roles in the assessment of patients in the critical care setting. More recently, multidetector row CT (MDCT) and MRI are being used increasingly for evaluation of coronary artery disease, cardiac structure and function, coronary artery anomalies, cardiac masses, pericardial disease, valvular disease, postoperative cardiovascular abnormalities, venous thromboembolism and acute aortic syndromes, often with other ancillary findings that can provide important clinical information. The three most common life-threatening cardiovascular processes in which advanced imaging plays a role, particularly CT, are discussed, including pulmonary embolism, aortic dissection, and coronary artery disease.

Detection of non-ST-elevation myocardial infarction and unstable angina in the acute setting: meta-analysis of diagnostic performance of multi-detector computed tomographic angiography

Background

Multi-detector computed tomography angiography (MDCTA) has been increasingly used in the evaluation of the coronary arteries. The purpose of this study was to review the literature on the diagnostic performance of MDCTA in the acute setting, for the detection of non-ST-elevation myocardial infarction (NSTEMI) and unstable angina pectoris (UAP).

Methods

A Pubmed and manual search of the literature published between January 2000 and June 2007 was performed. Studies were included that compared MDCTA with clinical outcome and/or CA in patients with acute chest pain, presenting at the emergency department. More specifically, studies that only included patients with initially negative cardiac enzymes suspected of having NSTEMI or UAP were included. Summary estimates of diagnostic odds ratio (DOR), sensitivity and specificity, negative (NLR) and positive likelihood ratio (PLR) were calculated on a patient basis. Random-effects models and summary receiver operating curve (SROC) analysis were used to assess the diagnostic performance of MDCTA with 4 detectors or more. The proportion of non assessable scans (NAP) on MDCTA was also evaluated. In addition, the influence of study characteristics of each study on diagnostic performance and NAP was investigated with multivariable logistic regression.

Results

Nine studies totalling 566 patients, were included in the meta-analysis: one randomised trial and eight prospective cohort studies. Five studies on 64-detector MDCTA and 4 studies on MDCTA with less than 64 detectors were included (32 detectors n = 1, 16 detectors n = 2, 16 and 4 detectors n = 1). Pooled DOR was 131.81 (95%CI, 50.90–341.31). The pooled sensitivity and specificity were 0.95 (95%CI, 0.90–0.98) and 0.90 (95%CI, 0.87–0.93). The pooled NLR and PLR were 0.12 (95%CI, 0.06–0.21) and 8,60 (95%CI, 5.03–14,69).

The results of the logistic regressions showed that none of the investigated variables had influence on the diagnostic performance or NAP

Conclusion

MDCTA of the coronary arteries performs good to excellent in the diagnosis of coronary artery disease in the acute setting and it can be used for early exclusion of NSTEMI or UAP in patients in the emergency department.

Impact of 64-slice cardiac computed tomographic angiography on clinical decision-making in emergency department patients with chest pain of possible myocardial ischemic origin

To examine the impact of contrast enhanced multidetector computed tomography (MDCT) on clinical decision-making in patients who present to the emergency department (ED) with chest pain of possible ischemic origin, we studied 58 consecutive patients (age 56 +/- 10 years, 36% female) with chest pain, intermediate risk, and no ischemic electrocardiographic changes or increased biomarker measurements. After standard ED patient assessment including cardiology consultation, a diagnosis of acute coronary syndrome was made in 41 patients (71%), hospitalization was recommended in 47 (81%), and 32 (55%) were scheduled for an early invasive strategy. Patients underwent 64-slice contrast agent-enhanced MDCT with image reconstruction in multiple formats using retrospective electrocardiographic gating, which revealed normal (no or trivial atheroma) coronary vasculature in 15 patients, nonobstructive atheroma in 20 patients, and obstructive coronary disease (> or =1 luminal narrowing of > or =50%) in 23 patients. After MDCT, the diagnosis of acute coronary syndrome was revised in 18 of 41 patients (44%; 16 normal MDCT/widely patent stents, 2 alternative diagnoses), planned hospitalization canceled in 21 of 47 patients (45%; 13 normal MDCT/patent stent, 8 minor branch vessel disease), and planned early invasive strategy altered in 25 of 58 patients (43%; unnecessary in 20 of 32, advisable in 5 of 26 others). Effect of MDCT on clinical decisions was greater in the 36 patients without known preceding coronary disease. In 32 patients discharged from the ED (11 after initial triage, 21 patients after MDCT), there were no major adverse cardiac events (e.g., death, myocardial infarction, unplanned revascularization) during a 12-month follow-up period. In conclusion, contrast agent-enhanced 64-slice cardiac MDCT was a valuable diagnostic tool in the ED triage of patients with chest pain of possible ischemic origin and decreased the need for hospitalization by almost half in this patient cohort.

CT angiography: front line for acute coronary syndromes now?

See article on page 1386

Emerging cardiovascular imaging techniques to non-invasively detect coronary artery disease

The current reference standard for the non-invasive detection of coronary artery disease (CAD) in patients who present with symptoms suggestive of CAD is either an exercise or pharmacologic stress radionuclide examination. Although useful, this test is limited by its relatively poor spatial resolution, high cost and need for ionizing radiation. Alternative non-invasive tests that are now clinically available include rest or pharmacologic stress echocardiography, pharmacologic stress during magnetic resonance perfusion imaging and multislice computed tomographic coronary angiography. This paper will present the advantages and disadvantages of stress techniques, and new developments that will further improve the accuracy of these tests.

Role of cardiac computed tomography and magnetic resonance imaging in the evaluation of acute chest pain in the emergency department

Evaluation of patients presenting with chest pain to the emergency department remains a challenging task because of a variety of etiologies that range from benign to potentially fatal. Although majority of patients do not have myocardial ischemia as the cause of their presentation, the clinical work up can be time consuming, costly and inconclusive. Recent technical advances in cardiac computed tomography and magnetic resonance imaging have led to better diagnostic accuracy in evaluating patients with chest pain. In this paper, we review the role of cardiac computed tomography and magnetic resonance imaging in evaluating patients with chest pain in the emergency department.