History
A 70-year-old female patient, suffering from hypertension, came to the hospital complaining of increasing chest discomfort suspicious of angina. Laboratory and electrocardiographic (ECG) tests as well as bicycle ergometry showed no evidence of myocardial ischemia. Echocardiography revealed severe sclerosis of the tricuspid valve, and minimal aortic valve insufficiency. The patient was slim and a non-smoker. Coronary CT angiography (CCTA) was requested and performed on a dual source CT, a SOMATOM Pro.Pulse, to rule out obstructive coronary disease.
Diagnosis
CCTA images revealed two anomalous origins of the left coronary arteries. The left anterior descending coronary artery (LAD) and the left circumflex coronary artery (Cx) originated separately off the left coronary sinus, with normal courses, without a common left main coronary artery (LM). All coronary arteries were free of plaque and stenosis (CAD-RADS 0). A small atrial septal defect (ASD) with a left-to-right shunt was seen. The coronary system was RCA dominant. There was no evidence of any structural cardiac abnormalities. The patient’s symptoms were presumably triggered by a hypertensive crisis.
Fig. 1: Cinematic VRT images (Fig. 1a and 1c) and a MPR image (Fig. 1b) show that the LAD and the Cx originate separately off the left coronary sinus, with normal courses, without a common LM. The tricuspid aortic valve appeared normal, as well as the origin and the course of the RCA.
Fig. 2: MPR images (Fig. 2a and 2c) and a cinematic VRT image (Fig. 2b) show a small ASD (arrows) with left-to-right shunt.
Comments
Most anomalous coronary origins are incidentally discovered in adults. The anomaly in this case is benign, causing no hemodynamic impairment or ischemic consequences. However, its identification is important as it may complicate coronary catheterization and cardiac surgery. A small ASD, often found later in life, usually doesn’t require any treatment. Regular health checkups may be needed for observation. In the ESC-guidelines, non-invasive functional imaging for myocardial ischemia or CCTA has been recommended as a first-line test for symptomatic patients without prior history of coronary artery disease. [1] Technically, CCTA requires a high temporal resolution and ECG synchronization to overcome the challenge of imaging a beating heart without motion artifacts. With the SOMATOM Pro.Pulse, a high temporal resolution of 86 ms is enabled through the dual source CT principle. Optimal image quality is achieved, even though the patient’s heart rate varied between 35 to 50 bpm during the acquisition, using a Prospectively ECG triggered sequential scan mode. This mode, as well as the 70 kV setting, contributes to the reduction of the radiation dose (4.1 mGy). The contrast-to-noise ratio is improved, despite the low radiation dose, as the iodine contrast enhancement benefits from lower kV settings. It is also worth noting that, patient preparation prior to scanning, such as practicing the breathing command, is also important. In this case, the CCTA performed aided the physician to confidently rule out the suspected obstructive coronary disease.
Examination Protocol
