Congenital coronary artery anomalies in adults: non-invasive assessment with multidetector CT

Transcription

1 The British Journal of Radiology, 82 (2009), PICTORIAL REVIEW Congenital coronary artery anomalies in adults: non-invasive assessment with multidetector CT 1 A R ZEINA, MD, 2 J BLINDER, MD, 3 D SHARIF, MD, 3 U ROSENSCHEIN, MD and 1 E BARMEIR, MD 1 Department of Radiology and MAR Imaging Institute, Bnai Zion Medical Center, Faculty of Medicine, Technion, Haifa, 2 MAR Imaging Institute, Bikur Holim Hospital, Jerusalem and 3 Department of Cardiology, Bnai Zion Medical Center, Faculty of Medicine, Technion, Haifa, Israel ABSTRACT. Congenital coronary anomalies (CCAs) are uncommon but can cause sudden cardiac death or other symptoms of myocardial ischaemia, especially in young healthy subjects. Conventional coronary angiography (CA) is an invasive and expensive procedure, and cannot provide three-dimensional data on the anomalous vessel. Electrocardiographic gated multidetector CT (MDCT) has been reported to be useful for non-invasive evaluation of CCAs. The purpose of this pictorial review is to discuss and illustrate different CCAs in terms of clinical importance, type and manifestations using MDCT. Knowledge of the CT appearances and an understanding of the clinical significance of these anomalies are essential for making the correct diagnosis and planning patient treatment. Received 31 August 2006 Revised 8 February 2007 Accepted 6 March 2007 DOI: /bjr/ The British Institute of Radiology Congenital coronary anomalies (CCAs) are uncommon and the vast majority are diagnosed incidentally during coronary angiography (CA) or necropsy. They affect,1% of the population, with 87% of affected individuals having anomalies of origin and distribution and 13% having coronary artery fistulae (CAF) [1 2]. An isolated single coronary artery occurs only in,0.024% of the population [3]. The incidence does not appear to be related to gender. CCAs are usually asymptomatic; however, some may cause sudden cardiac death or other symptoms of myocardial ischaemia, especially in young adults [4]. To date, the main diagnostic method for the detection of coronary anomalies has been selective CA. Although CA is an effective diagnostic tool, it is clearly invasive and associated with procedural morbidity (1.5%) and mortality (0.15%) risks [5]. Recognition of important clues and specific angiographic views are required to delineate clearly various CCAs. Owing to its two-dimensional nature, CA cannot show reliably the relationship of aberrant vessels with the underlying cardiac structures. These limitations can be overcome by using a noninvasive diagnostic modality that acquires full threedimensional (3D) data from both the heart cavities and the coronary arteries. Potential techniques that have been reported to be useful for the evaluation of CCAs are MRI and mutidetector CT (MDCT) CA. However, the spatial resolution achievable with cardiac MRI ( mm) is currently inadequate for coronary artery imaging, particularly for meticulous analysis of the distal arterial course. In addition, the inherent temporal Address correspondence to: Abdel-Rauf Zeina, Department of Radiology and MAR Imaging Institute, Bnai Zion Medical Center, 47, Golomb St, P.O.B. 4940, Haifa 31048, Israel. raufzeina3@hotmail.com resolution of MRI is unsatisfactory, as the time required for MRI acquisition is reported to range from 25 min to 50 min per study. In comparison, MDCT allows rapid acquisition of the entire 3D cardiac volume of data in a single scan (within 10 s on a 64-row MDCT scanner). Owing to its high spatial resolution ( mm), it provides excellent distal coronary artery visualization, including the small side branches. This resolution is approaching, but remains inferior to, that of conventional CA, i.e mm. As mentioned above, the data using MDCT is acquired as a volume, and retrospective electrocardiographic (ECG) gating is performed to reconstruct the images. This technique allows for the selection of the optimal reconstruction position with minimal motion and thus minimal artefacts, resulting in high-quality images of the heart cavities and the coronary arteries, including their origin, course and termination. Radiation exposures are relatively high in MDCT CA, ranging from 5 10 msv. Overall, the effective dose can be reduced substantially by using the ECG tube current modulation (reduction of tube output during the systolic phases of each cardiac cycle) which, therefore, compares favourably with that of conventional CA [6]. The aim of this pictorial review is to illustrate the spectrum of MDCT findings that may be seen in subjects with CCAs, as familiarity with the CT appearances and an understanding of the clinical significance of these anomalies are essential in making a correct diagnosis and planning patient treatment. Normal origin and course of coronary arteries The coronary arteries are the first vessels that branch from the aorta, normally originating below the junction 254 The British Journal of Radiology, March 2009

2 Pictorial review: Assessment of coronary artery anomalies with MDCT between the bulbus and the ascending aorta, i.e. at the sinotubular junction. The coronary orifices are located in the centre of the corresponding aortic sinuses and slightly above the free margin of the cusp (Figure 1). Normally, an individual has two or, sometimes, three coronary ostia. Often, the conal branch of the right coronary artery (RCA) may arise separately from the right sinus [7] (Figure 2). The left coronary ostium is usually single, giving rise to the left main coronary artery (LMCA) that branches into the left anterior descending (LAD) and left circumflex (LCX) coronary arteries. The LAD courses in the interventricular groove, whereas the RCA and LCX artery course in the right and left atrioventricular grooves, respectively (Figure 1). The coronary arteries are vessels located in the epicardium, although they may penetrate into the myocardium for part of their route (myocardial bridging). The intramyocardial coronary artery segment is termed a tunnelled segment. This condition is better visualized on curved multiplanar reformatted images in diverse planes (Figure 3). Types and MDCT findings of CCAs Multiple coronary ostia The LAD and LCX arteries may arise separately from the left sinus of Valsalva (LSV) with an absence of the LMCA. Separate ostia of the LAD and LCX arteries occur in 0.41% of subjects with an otherwise normal anatomy [8] (Figure 4). Multiple ostia in both aortic sinuses have also been reported [7]. Multiple ostia usually present no major clinical problems, but they may cause difficulty in cannulating the vessels during CA. High take-off High take-off refers to an unusually high origin of either the RCA or the LAD artery from the ascending aorta at a point above the junctional zone between its sinus and the tubular part [9]. High take-off positions are without any haemodynamic significance, but they may lead to unexpected angiographic problems while localizing and engaging the orifices. High take-off is better represented on the angiographic view or volumerendered reformatted images (Figure 5). Single coronary artery In this condition, the LMCA and RCA arise with a common ostium from the right, left or non-coronary sinus. This is a very rare CCA that is seen in only % of the population [10]. The involved coronary artery may route interarterially between the aortic root and the pulmonary trunk before bifurcating into its branches (Figure 6). Subjects with such an anomaly are at increased risk for sudden death [9]. Origin from non-coronary or opposite sinus Left and right coronary arteries may also arise from the non-coronary sinus (Figure 7) or their opposite coronary sinuses [11]. When the LMCA originates from Figure 1. Normal electrocardiographic gated multidetector CT anatomy of the coronary arteries and branches. (a) Threedimensional volume-rendered image of the coronary tree shows a normal aortic root (A) and coronary artery anatomy: left main coronary artery (LMCA), left anterior descending (LAD), left circumflex (LCX), right coronary artery (RCA), posterior descending artery (arrowhead) and posterolateral branch (small arrow). Large arrows indicate the right (large white arrow) and left (large open arrow) sinus of Valsalva. (b) Cardiac transparency image showing the course of the coronary arteries and their anatomical relationship. A, aorta; D, first diagonal; LV, left ventricle; P, main pulmonary artery; RV, right ventricle. The British Journal of Radiology, March

3 A R Zeina, J Blinder, D Sharif et al Figure 2. A 53-year-old man with multiple ostia and separate origins of the right coronary artery (RCA) and conus branch (CB). (a) Maximum intensity projection multidetector CT image shows separate ostia of the RCA and CB from the right sinus of Valsalva (RSV). A, aorta. (b) Three-dimensional volume-rendered image of the aortic root (A) shows the separate origin of the conus branch (arrow) from the RSV. the opposite or non-coronary sinus, or vice versa, the anomalous artery takes one of four aberrant pathways to reach its proper vascular territory: (i) anterior to the right ventricular outflow tract (Type A); (ii) interarterial (between the aorta and pulmonary trunk; Type B); (iii) through the crista supraventricularis portion of the septum (Type C); and (iv) dorsal to the aorta (Type D). The RCA arises from the LSV as a separate vessel or as a branch of a single coronary artery in % of patients who undergo angiography (Figure 8) [2]. The LMCA arises from the right sinus of Valsalva (RSV) in % of patients who undergo angiography [12]. The LCX artery may arise anomalously from the RSV (approximately % of the population), usually passing behind the aortic root (Figure 9) [2]. Coronary artery fistulae CAF are rare, being detected in approximately % of coronary angiograms [13]. Most originate from the RCA and almost always drain into low-pressure chambers of the heart (i.e. right ventricle, right atrium and pulmonary artery). Their aetiology is most frequently congenital; however, acquired forms have been described after cardiac operations or biopsies, chest irradiation or as a complication of percutaneous coronary intervention. Patients with small CAF remain asymptomatic, whereas those with high-flow fistulae and enlarged vessels may develop myocardial ischaemia and congestive heart failure. The presence of symptoms, complications and significant left-to-right shunt are currently the main indications for CAF closure. CAF are better represented on 3D volume-rendered images, although one needs to view the axial images for complete evaluation (Figures 10 and 11). When complex anatomy or intervention is contemplated, conventional CA may not be sufficient. Figure 3. A 56-year-old man with myocardial bridging. Curved multiplanar reformatted multidetector CT image showing a band of myocardial muscle overlying the mid left anterior descending (LAD) artery segment, corresponding to myocardial bridging (arrows). Inset: cross-sectional reformatted image showing the tunnelled segment completely surrounded by muscle fibres (arrow). LCX, left circumflex; LMCA, left main coronary artery; LV, left ventricle. Conclusion ECG-gated MDCT is a non-invasive 3D imaging technique that provides an excellent overview of the cardiac and complex vascular anatomy, and could be helpful for planning future cardiovascular therapeutic approaches, either interventional or surgical. The identification and assessment of CCAs seem to constitute an 256 The British Journal of Radiology, March 2009

4 Pictorial review: Assessment of coronary artery anomalies with MDCT Figure 4. A 37-year-old man with multiple ostia and separate origins of the left anterior descending (LAD) and left circumflex (LCX) arteries. (a) Thick slab maximum intensity projection multidetector CT image shows the absence of the left main coronary artery, with separate ostia of the LAD and LCX arteries from the left sinus of Valsalva (LSV). A, aorta. (b) Virtual angioscopy demonstrating the LAD and LCX orifices. Figure 5. A 45-year-old man with high take-off of the right coronary artery (RCA). Angiographic view reformatted multidetector CT image shows the high take-off (arrow) of the RCA above the sinotubular junction (dashed line). A, aorta; LM, left main coronary artery; CS, coronary sinus. The British Journal of Radiology, March

5 A R Zeina, J Blinder, D Sharif et al Figure 6. A 58-year-old man with a single coronary artery. (a) Axial thick slab maximum intensity projection image shows the malignant course (interarterial) of the left main artery (LM) between the aorta (A) and right ventricle outflow tract (RVOT). LA, left atrium; LAD, left anterior descending artery; LCX, left circumflex; RCA, right coronary artery. (b) Cardiac transparency image shows the anomalous origin of the LM, its course and the detailed anatomic relationship. RA, right atrium; RV, right ventricle. (c) Three-dimensional volume-rendered multidetector CT image of the aortic root (A) and coronary tree shows only one coronary artery arising from the right coronary sinus (arrow). Note the high take-off of the single coronary artery above the sinotubular junction. 258 The British Journal of Radiology, March 2009

6 Pictorial review: Assessment of coronary artery anomalies with MDCT Figure 7. A 58-year-old man with a left main artery arising from the non-coronary sinus (NCS). Axial thick slab maximum intensity projection multidetector CT shows an anomalous left main artery (arrow) originating from the NCS and coursing between the aorta (A) and the left atrium (LA). Note that the right coronary artery (RCA) arises normally from the right coronary sinus (RCS). No coronary artery is arising from the left coronary sinus (LCS). LAD, left anterior descending artery; LCX, left circumflex; RA, right atrium; RVOT, right ventricle outflow tract. Figure 9. A 59-year-old man with a left circumflex artery (LCX) anomalous origin. Cardiac transparency multidetector CT image shows the LCX arising separately close to the origin of the right coronary artery (RCA) from the right coronary sinus (arrow) and coursing below and behind the aortic root. Figure 8. A 54-year-old man with an anomalous origin and course of the right coronary artery (RCA). Thin slab maximum intensity projection multidetector CT image shows an interarterial RCA (arrows) originating directly from the left sinus of Valsalva and coursing between the aorta (A) and the right ventricle outflow tract (RVOT). The RCA take-off is at an acute angle. LM, left main coronary artery. The British Journal of Radiology, March

7 A R Zeina, J Blinder, D Sharif et al Figure 10. A 26-year-old woman with total correction of the Tetralogy of fallot and a congenital left anterior descending artery (LAD) right ventricle fistula. (a) Oblique thick slab maximum intensity projection multidetector CT view shows a dilated and tortuous proximal LAD draining directly into the right ventricle (RV) (arrow). A, aorta; LMCA, left main coronary artery. (b) Left coronary angiogram shows a coronary artery fistula arising from the proximal LAD artery and emptying into the RV (arrow). appropriate clinical use for this technology, and the examples illustrated provide persuasive evidence in support of this. Acknowledgments The authors are very grateful to Mrs Hilary Movsowitz for her invaluable competence and assistance in the preparation of this work. Figure 11. A 58-year-old man with a complex coronary pulmonary artery fistula. A three-dimensional volume-rendered multidetector CT image shows a plexus of fine tortuous vessels arising from the dilated proximal left anterior descending artery (LAD) to form a network of vessels (open arrows) that eventually coalesce to a major dilated draining vein (arrowhead), crossing the anteroinferior aspect of the pulmonary trunk (PT) before draining into the right ventricle outflow tract. A feeding vessel (arrow) originating separately from the right coronary sinus is noted. Multiple calcified plaques are also noted along the proximal segment of the LAD. A, aorta; LV, left ventricle; RCA, right coronary artery; RV, right ventricle. References 1. Click RL, Holmes DR, Jr, Vlietstra RE, Kosinski AS, Kronmal RA. Anomalous coronary arteries: location, degree of atherosclerosis and effect on survival a report from the Coronary Artery Surgery Study. J Am Coll Cardiol 1989;13: Yamanaka O, Hobbs RE. Coronary artery anomalies in 126,595 patients undergoing coronary arteriography. Cathet Cardiovasc Diagn 1990;21: Sevrukov A, Aker N, Sullivan C, Jelnin V, Candipan RC. Identifying the course of an anomalous left coronary artery using contrast-enhanced electron beam tomography and three-dimensional reconstruction. Catheter Cardiovasc Interv 2002;57: Albert CM, Mittleman MA, Chae CU, Lee IM, Hennekens CH, Manson JE. Triggering of sudden death from cardiac causes by vigorous exertion. N Engl J Med 2000;343: Scanlon PJ, Faxon DP, Audet AM, Carabello B, Dehmer GJ, Eagle KA, et al. ACC/AHA guidelines for coronary angiography. A report of the American College of Cardiology/American Heart Association Task Force on practice guidelines (Committee on Coronary Angiography). Developed in collaboration with the Society for Cardiac Angiography and Interventions. J Am Coll Cardiol 1999;33: Jakobs T, Becker C, Ohnesorge B, Flohr T, Suess C, Schoepf UJ, et al. Multislice helical CT of the heart with retrospective ECG 260 The British Journal of Radiology, March 2009

8 Pictorial review: Assessment of coronary artery anomalies with MDCT gating: reduction of radiation exposure by ECG-controlled tube current modulation. Eur Radiol 2002;12: Vilallonga JR. Anatomical variations of the coronary arteries: the most frequent variations. Eur J Anat. 2003;1: Danias PG, Stuber M, McConnell MV, Manning WJ. The diagnosis of congenital coronary anomalies with magnetic resonance imaging. Coron Artery Dis 2001;12: Kim SY, Seo JB, Do KH, Heo JN, Lee JS, Song JW, et al. Coronary artery anomalies: classification and ecg-gated multi detector row CT findings with angiographic correlation. Radiographics 2006;26: Desmet W, Vanhaecke J, Vrolix M, Van de Werf F, Piessens J, Willems J, et al. Isolated single coronary artery: a review of 50,000 consecutive coronary angiographies. Eur Heart J 1992;13: Manghat NE, Morgan-Hughes GJ, Marshall AJ, Roobottom CA. Multidetector row computed tomography: imaging congenital coronary artery anomalies in adults. Heart 2005;91: Chaitman BR, Lesperance J, Saltiel J, Bourassa MG. Clinical, angiographic, and hemodynamic findings in patients with anomalous origin of the coronary arteries. Circulation 1976;53: Said SA, el Gamal MI, van der Werf T. Coronary arteriovenous fistulas: collective review and management of six new cases changing etiology, presentation, and treatment strategy. Clin Cardiol 1997;20: The British Journal of Radiology, March