DOI:10.2214/AJR.05.1586
AJR 2006; 187:W227-W228
© American Roentgen Ray Society
16-MDCT in the Evaluation of Coronary Cameral Fistula
Priya Jagia,
Kewal C. Goswami,
Sanjiv Sharma and
Gurpreet S. Gulati
All India Institute of Medical Sciences New Delhi, India
A 21-year-old nonsmoker, nondiabetic, normotensive man with no family
history of coronary artery disease presented with an 8-year history of
palpitation and progressive angina on exertion. There was no history of pain
while at rest. Clinical examination revealed normal systemic blood pressure
and bounding peripheral pulses. Systemic examination revealed a hyperdynamic
apex with a localized continuous murmur of grade 3/6 in left fourth and fifth
intercostal space near the left parasternal region. ECG revealed left
ventricular hypertrophy without significant ST-T wave changes.
A chest radiograph showed mild cardiomegaly, and 2D echocardiography
revealed a large tortuous right coronary artery communicating with the right
ventricle, with continuous flow on color Doppler, suggesting a left-to-right
shunt.
An ECG-gated 16-MDCT (Sensation 16, Siemens Medical Solutions, Germany)
scan was performed to define the coronary anatomy. Nonionic contrast material
(iohexol, 80 mL at 4 mL/s) was injected with bolus tracking over the ascending
aorta. Parameters for scanning included slice thickness, 0.75 mm; rotation
time, 0.42 second; scanning time, 18 seconds. The heart rate was 66 beats per
minute. Axial images were reconstructed at various time points along the R-R
interval and were reviewed along with the 3D reconstructions. There was a
dilated and tortuous right coronary artery arising from the right coronary
sinus (Fig. 1A) and draining
via a hypertrophied posterior descending artery into the right ventricle
(Fig. 1B). Curved
reconstruction images showed no significant stenosis along the course of the
fistula. Small outpouchings and irregularity were noted in the fistulous
structure just before its drainage into the right ventricle
(Fig. 1B). The left coronary
artery and its branches were normal in origin, course, and caliber.
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Fig. 1B —21-year-old man with angina. Oblique axial
maximum-intensity-projection image shows dilated distal right coronary artery
and hypertrophied posterior descending artery draining into right ventricle.
Small outpouchings and irregularity are seen in distal right coronary artery.
RV = right ventricle, LV = left ventricle.
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The patient underwent cardiac catheterization, which revealed significant
oxygen stepup at the right atrial level with a pulmonary-to-systemic flow
ratio of 2:1. A selective coronary angiogram showed a dilated tortuous right
coronary artery draining into the right ventricle. The patient subsequently
underwent surgery for closure of the fistula.
A coronary cameral fistula is a communication between a coronary artery and
a chamber of the heart. Symptoms associated with the lesion include those
caused by volume overloading of the heart or by coronary artery steal
secondary to the fistulous communication. Traditional imaging techniques to
diagnose a coronary cameral fistula include echocardiography and catheter
angiography [1]. However,
echocardiography is operator dependent and limited by availability of a good
acoustic window, and it may not show the entire course of the fistula.
Catheter angiography is invasive, and overlap between a tortuous fistula and
adjacent cardiovascular structures may hamper complete evaluation of the
lesion.
MDCT is an emerging noninvasive technique for the imaging of coronary
arteries because of its high contrast and spatial resolution
[2,
3]. Significant improvement of
temporal resolution can be achieved by controlling the heart rate and reducing
the gantry rotation time. We have reported an interesting case of a coronary
artery fistula in which complete anatomic delineation was achieved using this
technique. MDCT may be advantageous over catheter angiography because of its
ability to show the fistula separate from the surrounding cardiovascular
structures along with any aneurysm or obstruction along its course. Thus, it
may be preferred as the initial noninvasive imaging technique when a coronary
cameral fistula is suspected.
References
- Nair T, Joy MV, Subramanyan R, Venkitachalam CG, Balakrishnan KG.
Two-dimensional and Doppler echocardiographic study of coronary arteriovenous
fistulas. Indian Heart J 1990;42
: 149-152[Medline]
- Flohr TG, Schaller S, Stierstorfer K, Bruder H, Ohnesorge BM,
Schoepf UJ. Multi-detector row CT systems and image-reconstruction techniques.
Radiology 2005;235
: 756-773[Abstract/Free Full Text]
- Heuschmid M, Kuettner A, Schroeder S, et al. ECG-gated 16-MDCT of
the coronary arteries: assessment of image quality and accuracy in detecting
stenoses. AJR 2005;184
: 1413-1419[Abstract/Free Full Text]
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