This 19-year-old was originally diagnosed with Kawasaki disease at age 7. He has been followed serially with echocardiography and thallium myocardial perfusion exams because of known bilateral coronary artery aneurysms. He has done well clinically and was referred for coronary CTA to evaluate the size of his aneurysms and to evaluate for possible coronary stenoses. His last prior coronary angiogram was 11 years ago at age 8.

Kawasaki disease affects the mucous membranes, lymph nodes, walls of the blood vessels, and the heart. It is an inflammatory vasculitis, and may be autoimmune in origin. This vasculitis can be especially dangerous when it damages the heart’s coronary arteries, causing an abnormal dilation or aneurysm formation in these vessels. In rare cases, arterial damage related to Kawasaki syndrome can significantly interfere with the heart’s blood supply, even to the point of causing heart failure, myocardial ischemia, and sudden death.

Clinical findings

The coronary CTA exam images helped the radiologist determine the following:

There is a focal aneurysm involving the distal left main coronary artery extending into the LAD. This aneurysm is 25 mm in length and is 11 mm in diameter (Figure 1).

There is some circumferential calcification which is relatively thin. The origin of the left main from the aorta is slightly prominent, measuring 7 mm.

There is mild narrowing at the origin of the LAD from the aneurysm itself, measuring 2.4 mm in diameter. Distal to this, the vessel becomes slightly prominent, measuring up to 6 mm in diameter before eventually tapering off.

The left circumflex also arises from the aneurismal sac, with mild to moderate relative narrowing at its origin. One of the proximal marginal branches also arises from the aneurysm sac and again there is mild narrowing of its origin identified.

A focal aneurysm of the RCA is identified, again involving the very proximal RCA. The origin is only minimally prominent at 4 mm, the maximal diameter of the aneurysm is 9 mm and it is approximately 11 mm in length (Figure 2).

Distal to the aneurysm, the RCA is unremarkable with the exception of a congenital anomaly of a split distribution (Figure 3). One portion continues in the A-V groove while a second portion branches off to feed the interventricular region.

The PDA arises from the right coronary artery. This vessel is patent.

Based on the findings, the patient has multiple focal aneurysms in the left main, LAD, and the proximal RCA. Also noted is a narrowing of the origin of the LAD from the aneurysm as well as the first diagonal, marginal and left circumflex coronary arteries.

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It is impressive that the LightSpeed VCT XT is able to pinpoint these aneurysms and measure them with detailed accuracy. The images are critical in helping to accurately determine the current status of the patient’s known heart disease and will be helpful in following the progression in the future. Because he remains asymptomatic and no obstructive disease was depicted, no intervention was required at this time.
br> The ability to accurately acquire a coronary angiogram in this case with approximately 2.3 mSv* of effective dose opens new possibilities for further evaluation. Previously, this patient has had yearly nuclear myocardial perfusion exams, which can each approach 50 mSv of effective dose, depending on the technique used.

In the future, with the advent of SnapShot Pulse on LightSpeed VCT XT, the referring cardiologist is considering performing CCTA every other year, alternating yearly with a nuclear myocardial perfusion exam.

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