Visualization of coronary artery anomalies by contrast-enhanced multi-detector row spiral computed tomography

Abstract

Background

We investigated the potential of 16-slice multi-detector row spiral CT (MDCT) with retrospective ECG-gating for evaluation of coronary artery anomalies.

Methods

A total of 35 patients (23 men, 12 women, 19–81 years) in whom anomalous coronary arteries had been detected by invasive coronary angiography underwent MDCT (Sensation 16, Siemens, Germany). During one breathhold, a contrast-enhanced (90 ml, 5 ml/s) volume data set of the heart was acquired (16 × 0.75mm collimation, gantry rotation 375 ms). Images were reconstructed with a slice thickness of 1.0 mm in 0.5-mm intervals using retrospective ECG-gated reconstruction. The 35 data sets and 80 data sets of patients with angiographically normal coronary anatomy were analysed in random order concerning the origin and course of the coronary arteries. The results were compared to invasive coronary angiography.

Results

All patients with coronary artery anomalies and all controls with normal coronary anatomy were identified by MDCT. In addition, the origins and course concerning their anatomical relationship to adjacent cardiac structures were visualized in all patients, including right-sided origin of the left main (n = 10), left anterior descending coronary artery (n = 4) or left circumflex coronary artery (n = 10); left-sided origin of the right coronary artery (n = 6); four coronary fistula to the pulmonary artery (two from the left anterior descending, one from the right coronary artery, one from the left main), and one fistula from the circumflex coronary artery to the left atrium

Conclusions

The study demonstrates that MDCT is a reliable noninvasive technique to identify and define anomalous coronary arteries and their course.

Introduction

Congenital coronary artery anomalies occur in only 0.6–1.3% of patients referred for coronary angiography [1], [2], [3], [4], [5], [6]. Although anomalous coronary arteries lack clinical significance in the majority of these patients, certain anomalies have been associated with sudden cardiac death and ischemic complications [2], [4], [6], [7], [8], [9], [10], [11], [12], [13], [14]. The exact anatomic definition of coronary artery anomalies and their course is therefore a prerequisite for every coronary artery imaging modality. Diagnosis of coronary artery anomalies is usually established during invasive coronary angiography. However, due to the projectional nature of conventional coronary angiography, which provides only a two-dimensional view of a vessel's complex three-dimensional path and fails to clearly visualize the relationship to surrounding structures, the identification of the course of the aberrant coronary artery can be difficult [15], [16], [17], [18] and misinterpretation is reported in up to 50% of patients [16]. Furthermore, the aberrant vessel may be overlooked or considered to be occluded if not selectively engaged [17]. Several recent reports have indicated the usefulness of noninvasive modalities, such as magnetic resonance imaging [19], [20], [21], electron beam tomography [22] and echocardiography [23], [24], [25] for detection and delineation of coronary artery anomalies. Contrast-enhanced multi-detector row spiral CT (MDCT) with retrospective ECG-gating has been shown to permit noninvasive visualization of the coronary arteries [26], [27] and the detection of coronary artery stenosis with high diagnostic accuracy [28], [29]. Moreover, some case reports and two studies with small patient numbers have indicated the potential of contrast-enhanced MDCT for the evaluation of congenital coronary anomalies [30], [31], [32], [33], [34].

In this study, we investigated the ability of 16-slice MDCT with a gantry rotation time of 375 ms for the non-invasive accurate identification of anomalous coronary arteries and definition of their anatomic course.