Demonstration of the Anomalous Origin of the Left Coronary Artery

from the Pulmonary Artery in Children using a Multi-Detector CT

Quanli Shen and Xihong Hu

Department of Radiology, Children’s Hospital, Fudan University, 399 Wanyuan Street, Shanghai, China

Keywords: Congenital Anomaly of the Coronary Artery, Computed Tomography, Children.

Abstract: Objective: To explore the value of multi-detector CT coronary angiography (CTCA) in detecting anomalous

origin of the left coronary artery from the pulmonary artery (ALCAPA) in children. Materials and methods:

Seven children aged from 2 months to 4 years who had surgically confirmed ALCAPA were enrolled in this

study. Their CTCA images were retrospectively analyzed. Results: The left coronary arteries were detected

to originate from the left wall of the main pulmonary artery in 2 patients, from the posterior wall of the main

pulmonary artery in 3 patients, and from the left pulmonary sinuse in 2 patients. In a 4-year-old girl, CTCA

showed collateral circulation between the right and the left coronary arteries. Conclusion: CTCA is a

valuable non-invasive method to show the anomalous origin of the coronary artery in small children with

ALCAPA.

1 INTRODUCTION

Anomalous origin of the left coronary artery from

the pulmonary artery (ALCAPA) is a rare congenital

cardiac anomaly. It is important to demonstrate the

anomalous origin of the left coronary artery and its

course before surgery. In this paper, we try to

explore the value of multi-detector CT coronary

angiography (CTCA) in detecting ALCAPA in

children.

2 MATERIALS AND METHODS

Seven children aged from 2 months to 4 years

(median age, 13 months) who had surgically

confirmed ALCAPA were enrolled in this study.

CTCA was performed with a 64-slice multidetector

CT scanner for all patients. Images were

reconstructed from the diastolic phase (75% R-R

interval) for a 4-year-old girl with heart rate 80 beats

per minute. For other patients with heart rates >120

beats per minute, images were reconstructed from

the end-systolic phase (45%~50% of the R-R

interval).

Two pediatric radiologists independently

assessed the image quality according to Paul et al

(Paul, 2011) and the origin of the coronary artery.

3 RESULTS

The result of image quality was summarized in

Table 1. CTCA showed enlargement of the left heart

in all patients. The left coronary arteries were

detected to originate from the main pulmonary artery

(MPA) in all patients (Figs. 1 and 2). The sites of

origin were summarized in Table 2. In a 4-year-old

girl, CTCA showed collateral circulation between

the right and the left coronary arteries (Fig. 3).

Table 1: Result of image quality.

Coronary artery Image quality scale

LMT

4.29±0.95

LAD

4.43±0.53

LCX

3.43±1.81

RCA

4.43±0.79

LMT = left main trunk, LAD = left anterior descending

artery, LCX = left circumflex artery, RCA = right

coronary artery.

Table 2: The origin of the left coronary artery.

Origin Case number

Left wall of the MPA 2

Posterior wall of the MPA 3

Left pulmonary sinuse 2

MPA = main pulmonary artery.

Shen Q. and Hu X..

Demonstration of the Anomalous Origin of the Left Coronary Artery from the Pulmonary Artery in Children using a Multi-Detector CT.

 2014 SCITEPRESS (Science and Technology Publications, Lda.)

Figure 1: CTCA in a 21-month-old girl with ALCAPA.

Axial CT image demonstrates the left coronary artery

originates from the left pulmonary sinuse (arrow). AO =

aortic artery, PA = pulmonary artery, RCA = right

coronary artery, LAD = left anterior descending coronary

artery, LCX = left circumflex coronary artery.

Figure 2: CTCA in a 5-month-old girl with ALCAPA.

Axial CT image demonstrates the left coronary artery

originates from the left wall of the main pulmonary artery

(arrow). PA = pulmonary artery, LCA = left coronary

artery.

Figure 3: CTCA in a 4-year-old girl with ALCAPA. Axial

CT image (a) demonstrates the left coronary artery

originates from the posterior wall of the main pulmonary

artery (arrow). Volume rendering image (b) shows the

dilated right coronary artery and the tortuous collateral

vessel between the right and the left coronary artery

(arrow). AO = aortic artery, PA = pulmonary artery, LCA

= left coronary artery, RCA = right coronary artery.

4 DISCUSSION

CTCA can provide direct anatomic detail of the

coronary arteries and their origins as well as the

degree of collateralization (Cowles, 2007).

Depending on the acquired raw data, various phases

of the cardiac cycle may be available. In children

with low heart rate, images are usually reconstructed

from the diastolic phase (around 70% of the R-R

interval). But for children with heart rates >80/min,

it has been shown that the end-systolic phase

(between 35% and 45% of the R-R interval)

provides the best sharpness for the coronary arteries.

In case of cardiac motion artefacts, additional sets

may be reconstructed from other available phases of

the cardiac cycle (Lederlin, 2011).

One drawback of CTCA is the ionizing radiation.

Children have unequivocally higher radiosensitivity

and longer life expectancy than the older population

(Goo, 2012). In our study, we lowered the tube

voltage to 80-kV. The tube current was adapted to

the body weight. These settings do not impair image

quality too much and are considered sufficient for

diagnostic evaluation.

5 CONCLUSIONS

In conclusion, CTCA with a low-dose technique is a

valuable non-invasive method to show the

anomalous origin of the coronary artery in small

children with ALCAPA, especially for patients

whose origin of the left artery cannot be detected by

TTE. It is helpful to make a correct diagnosis before

surgery and lower the mortality.

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