Coronary multidetector computed tomography in the assessment of patients with acute chest pain

Coronary angiography by computed tomography: coronary imaging evolves

Rapid technological advances have facilitated high-resolution noninvasive coronary angiography using multislice computed tomography. Appropriateness guidelines recently have been published in the Journal of the American College of Cardiology and endorsed by several imaging specialty societies. Clinical studies are now available supporting the use of this method in selected diagnostic situations, particularly when the exclusion of coronary artery disease is of paramount clinical concern.

Comprehensive cardiac CT study: evaluation of coronary arteries, left ventricular function, and myocardial perfusion--is it possible?

With advances in multidetector computed tomography (MDCT) technology, the new generation of 64-slice MDCT scanners with submillimeter collimation and a faster gantry rotation allows imaging of the entire heart in a single breath-hold with excellent temporal and spatial resolution. This potentially permits a comprehensive assessment of coronary anatomy, left ventricular function, and myocardial perfusion. As will be seen in this review of the current literature regarding 16- and 64-slice MDCT, there is great promise for a comprehensive cardiac computed tomography (CT) study. The available data support the notion that CT coronary angiography may be an alternative to invasive coronary angiography in symptomatic patients with a low to intermediate likelihood of having coronary artery disease. By use of the same data acquired for CT coronary angiography, evaluation of global and regional left ventricular function and myocardial perfusion can be added to the MDCT evaluation without additional exposure to contrast medium or radiation and may provide a more conclusive cardiac workup in these patients. The potential applications and limitations of coronary stenosis detection, global and regional left ventricular function, and myocardial perfusion assessment by MDCT will be reviewed. The full potential of cardiac MDCT is just beginning to be realized.

Evaluation of Acute Chest Pain in the Emergency Department: Utility of Multidetector Computed Tomography

Distinguishing insignificant from life-threatening causes of acute chest pain in patients who present to the emergency department remains a major challenge. Initial evaluation with history, electrocardiography, and biochemical markers is often unrevealing leading to additional workup. Radionuclide perfusion and echocardiography may be diagnostic but provide only indirect assessment of coronary status. The development of multidetector computed tomography (MDCT) and its increasingly frequent placement near the emergency suite has facilitated its use for the evaluation of serious noncardiac diagnoses such as pulmonary embolism and aortic dissection. Recent innovations in MDCT technology have facilitated the depiction of coronary arteries. These advances have led to the possibility of using CT to evaluate cardiac etiologies of chest pain, using either a comprehensive or triple rule out protocol to assess both cardiac and noncardiac causes or a dedicated coronary protocol. This article will review both options and describes our preliminary experience with the first of these protocols. The article also reviews the potential value of an acute chest pain CT protocol and the considerable challenges that remain prior to its implementation for routine clinical use.

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

BACKGROUND

Multidetector computed tomography (MDCT) has high diagnostic value for detecting or excluding coronary artery stenosis. We examined performance characteristics of MDCT for diagnosing or excluding an acute coronary syndrome in patients presenting to the emergency department (ED) with possible ischemic chest pain and examined relation to clinical outcome during a 15-month follow-up period.

METHODS AND RESULTS

We prospectively studied 58 patients (56+/-10 years of age, 36% female) with chest pain possibly ischemic in origin and no new ECG changes or elevated biomarkers. The patients underwent 64-slice contrast-enhanced MDCT, which showed normal coronary vessels (no or trivial atheroma) in 15 patients, nonobstructive plaque in 20 (MDCT-negative patients), and obstructive coronary disease (> or = 50% luminal narrowing) in 23 (MDCT-positive group). By further investigation (new elevation of cardiac biomarkers, abnormal myocardial perfusion scintigraphy and/or invasive angiography), acute coronary syndrome was diagnosed in 20 of the 23 MDCT-positive patients (ED MDCT sensitivity 100% [20/20], specificity 92% [35/38], positive predictive value 87% [20/23], negative predictive value 100% [35/35]). During a 15-month follow-up period, no deaths or myocardial infarctions occurred in the 35 patients discharged from the ED after initial triage and MDCT findings. One patient underwent late percutaneous coronary intervention (late major adverse cardiovascular events rate, 2.8%). Overall, ED MDCT sensitivity for predicting major adverse cardiovascular events (death, myocardial infarction, or revascularization) during hospitalization and follow-up was 92% (12/13), specificity was 76% (34/45), positive predictive value was 52% (12/23), and negative predictive value was 97% (34/35).

CONCLUSIONS

We found that 64-slice cardiac MDCT is a potentially valuable diagnostic tool in ED patients with chest pain of uncertain origin, providing early direct noninvasive visualization of coronary anatomy. ED MDCT had high positive predictive value for diagnosing acute coronary syndrome, whereas a negative MDCT study predicted a low rate of major adverse cardiovascular events and favorable outcome during follow-up.

Applications of multislice computed tomography in coronary artery disease

Multislice computed tomography (MSCT) provides high accuracy for noninvasive assessment of coronary artery disease (CAD). The introduction of the latest computed tomography (CT) technology allows comprehensive evaluation of various aspects of CAD, including the coronary calcium score, coronary artery stenoses, bypass patency, and myocardial function. Other applications, such as plaque characterization, first-pass perfusion imaging, and viability imaging using delayed contrast enhancement, are still under development and may demonstrate clinical utility in the future. Further improvements in CT hardware and imaging protocols are expected that may result in improved coronary artery imaging, new applications, and a significant reduction of radiation dose.

Multislice cardiac computed tomography in symptomatic middle-aged women

OBJECTIVE

To assess the accuracy of multislice cardiac computed tomography (MSCT) for detection of significant coronary artery disease (CAD) in middle-aged symptomatic women.

METHODS

We included 70 women (51+/-8 years) with complaints of chest pain or dyspnea, and an abnormal maximum exercise electrocardiogram (ECG) (8.6+/-1.4 metabolic equivalents). All had a MSCT using a 16 detector rows scanner, and coronary arteriography (CA). Blinded results of the two modalities were compared using a segment, vessel, and patient-based analysis.

RESULTS

On MSCT 36% had normal coronaries, 24% had significant CAD requiring revascularization, and the remainder had mild CAD. MSCT had reasonably high diagnostic accuracy at segment level (negative predictive value of 95%, positive predictive value 81%, specificity 99%, and sensitivity 50%), regarding single or multivessel CAD when both nonassessable and assessable segments were included in the analysis. The agreement between the segments comparing MSCT and CA for significant CAD was excellent at 98% (kappa value 0.89).

CONCLUSIONS

In this cohort of middle-aged symptomatic women with an abnormal stress test, 24% had significant CAD requiring intervention. MSCT was highly accurate in diagnosing significant CAD with an excellent negative predictive value.