Cardiovascular magnetic resonance and computed tomography in the evaluation of aneurysmal coronary-cameral fistula

Abstract

Coronary artery fistulas represent abnormal communications between a coronary artery and a major vessel like venae cavae, pulmonary arteries or veins, the coronary sinus, or a cardiac chamber. The latter is called coronary cameral fistula is a rare condition and is most of the times congenital but can be also post traumatic or post surgical, especially after cardiovascular interventional procedures. Most patients are asymptomatic and coronary-cameral fistulae are discovered incidentally during angiographic evaluation for coronary vascular disorders, while other patients have a clinical presentation ranging from angina pectoris to heart failure. In this article, we report a rare case of an aneurysmal right coronary cameral fistula draining into the left ventricle. Echocardiography usually represents the first diagnostic imaging approach, but often due to a poor acoustic window may not show the entire course of the fistula which is crucial for the final diagnosis. ECG-gated cardiovascular CT may play an important role in the evaluation of the origin, course, termination and morphology of the fistula, its relation to the adjacent anatomical structures as well as the morphology and contractility of the heart. Cardiac MRI instead plays an additional crucial role regarding not only the above mentioned factors but also in estimating the blood flow within the fistula, providing more detailed information about the cardiac function but also about myocardial wall viability.

Keywords: Coronary artery fistula; Coronary-cameral fistula; cardiovascular CT; cardiovascular MR; image reformats; late gadolinium enhancement.

Figure 1

42 year old male with aneurysmal coronary-cameral fistula. Findings: Transesophageal echocardiogram in a midesophageal aortic valve short-axis view (A) revealing a large pulsatile structure (yellow ovoid sign) originating from the right coronary sinus (empty arrow) probably corresponding to the RCA. Transesophageal color Doppler image in aortic valve long axis view (B) showing simultaneously the aortic valve regurgitation jet (vertical arrow) and the draining jet of coronary fistula into left ventricle at the base of posterior wall (horizontal arrow). Transthoracic color Doppler image in a modified apical view (C) indicating the possible tortuous course of the vascular structure along the atrio-ventricular groove (small black arrows) and consecutively the draining site into the left ventricle (big black arrow). Pulse wave-Doppler in a transthoracic long axis view (D) with sample volume at the entry site of coronary fistula in right coronary sinus, recording the predominantly diastolic flow (empty arrow). NCC= non coronary cusp, LCC= left coronary cusp, RCC= right coronary cusp, LA= left atrium, LV= left ventricle, Ao= aorta Technique: The ultrasound study was performed using a Philips iE 33 Matrix (Royal Philips Electronics, Eindhoven, Netherlands) with a transthoracic S5-1 sector array transducer (1–5MHz) and a transesophageal multiplane S7-2t omni sector array transduser (2–7MHz).

Figure 2

42 year old male with aneurysmal coronary-cameral fistula. Findings: Scout view from ECG-gated cardiovascular CT, shows obliteration of the right cardiophrenic angle which seems slightly more radiopaque than the common radiopacity of the pericardial fat pad (yellow arrow) corresponding to the anatomic location of the vascular structure figured at the echocardiographic study. Technique: ECG-gated 64-MDCT, (LightSpeed VCT 64-slice CT scanner, GE Healthcare, USA, 100 mAs, 120 kV, slice thickness, 0.625 mm, rotation time 0.40 second).

Figure 3

42 year old male with aneurysmal coronary-cameral fistula. Findings: ECG-gated cardiovascular CT, mediastinal window, width/level of 350/30 HU, in axial plane showing in (A) the origin of the CCF from the right coronary sinus (black round sign) and in (B) the giant aneurysmal dilatation of its proximal portion (black asterisk). Multiplanar reconstruction image in (C) shows the course and tortuosity of the fistula until its termination at the level of the LV base (yellow arrow). Maximum intensity projection image in (D) showing calcified atherosclerotic lesions along the fistula’s wall and thin collateral branches originating from the distal part of the fistula draining the adjacent epicardium (thin white arrows). Technique: ECG-gated 64-MDCT, (LightSpeed VCT 64-slice CT scanner, GE Healthcare, USA, 100 mAs, 120 kV, slice thickness, 0.625 mm, rotation time 0.40 second, scanning time 10 seconds, 1.15 pitch, heart rate of 55 bpm) after i.v administration of contrast material (Ultravist 370, 80mL at 4.5 mL/s).

Figure 4

42 year old male with aneurysmal coronary-cameral fistula. Findings: ECG-gated cardiovascular CT, Volume rendering technique image reconstruction showing an overview of the coronary-cameral fistula from its origin at the level of the right coronary sinus (yellow arrow) (A), the giant aneurysmal dilatation of its proximal portion with atherosclerotic wall lesions giving a coarse appearance of its wall (multiple thin white arrows) (B), and the tortuous course followed along the posterior atrio-ventricular groove before draining into the left ventricle (short yellow arrow) (C). Isolated image of the CCF showing thin collateral branches at its distal portion, directed to the epicardium (D). Technique: ECG-gated 64-MDCT, (LightSpeed VCT 64-slice CT scanner, GE Healthcare, USA, 100 mAs, 120 kV, slice thickness, 0.625 mm, rotation time 0.40 second, scanning time 10 seconds, 1.15 pitch, heart rate of 55 bpm) after i.v administration of contrast material (Ultravist 370, 80mL at 4.5 mL/s).

Figure 5

42 year old male with aneurysmal coronary-cameral fistula. Findings: (A) ECG-gated cardiovascular CT, mediastinal window, width/level of 350/30 HU, in axial plane showing the course of the fistula and the calcified atherosclerotic lesions on its wall (yellow arrows). Technique: ECG-gated 64-MDCT, (LightSpeed VCT 64-slice CT scanner, GE Healthcare, USA, 100 mAs, 120 kV, slice thickness, 0.625 mm, rotation time 0.40 second, scanning time 10 seconds, 1.15 pitch, heart rate of 55 bpm) after i.v administration of contrast media (Ultravist 370, 80mL at 4.5 mL/s). Findings: (B) In comparison with (A), ECG-gated cardiovascular MRI, T1- weighted turbo fast spin echo “black blood” sequence, almost at the same plane with (A), shows the fistula course and its relation with the adjacent anatomic structures. Technique: ECG-gated CMR, 1.5 T system Signa CV/i, GE Medical Systems, USA, with a 5-element cardiac phased- array coil, FOV: 340–400 mm; TR/TE: 6.0/3.8ms, matrix: 256×192; ST: 8 mm

Figure 6

42 year old male with aneurysmal coronary-cameral fistula. Findings: ECG-gated cardiovascular MRI. Cine SSFP sequences on axial oblique view showing (A) the turbulent jet flow at its origin at the level of the right coronary sinus and (B) at the proximal aneurysmal portion as well (yellow arrows). End-diastole image (C) showing the course of the fistula and the turbulent flow within its lumen (yellow arrow). End-systole image at the same level (D) indicating the draining of the fistula into the left ventricle base with a flow jet (yellow arrow). Technique: ECG-gated CMR, 1.5 T system Signa CV/i, GE Medical Systems, USA, with a 5-element cardiac phased- array coil, TR 3.5 ms, TE 1.7 ms, FA 55º, slice thickness 8 mm, in-plane resolution 1.2×1.8 mm.

Figure 7

42 year old male with aneurysmal coronary-cameral fistula. Findings: ECG-gated cardiovascular MRI. Contrast enhanced T1-weighted inversion recovery gradient echo (IR-GRE) sequences were acquired for late gadolinium enhancement. Data acquisition started 10min after Gadobutrol administration in short axis view (A and B), 3-chamber view (C) as well as 4-chamber view (D) showing no late gadolinium enhancement areas, excluding the presence of myocardial lesions that could be attributed to ischemia or volume overload related to the coronary-cameral fistula. Technique: ECG-gated CMR, 1.5 T system Signa CV/i, GE Medical Systems, USA, with a 5-element cardiac phased- array coil. Contrast enhanced T1-weighted inversion recovery gradient echo (IR-GRE) sequences FOV: 340–400 mm; TR/TE: 6.0/3.8ms, ?: 25º; matrix: 256×192; ST: 8 mm, i.v administration of Gadobutrol (Gadovist®, Bayer) at a dose of 0.1mmol/kg. Nulling of the myocardium signal was achieved using a time to invert (TI) range between 220 and 300 ms.

Figure 8

42 year old male with aneurysmal coronary-cameral fistula. Findings: Left anterior oblique projection (A): Aortography of the ascending aorta with a Pigtail catheter in the aortic root. The giant right coronary artery aneurysm is seen (white arrows). Left anterior oblique projection (B): Angiogram of the right coronary artery with a Pigtail catheter inside the aneurysm of the right coronary artery. The whole course of the giant right coronary artery fistula is seen (empty arrows). Technique: Angiographic system Philips, Integris Allura FD system, 66KV, 535mA