Pediatric Imaging Original Research

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1 Pediatric Imaging Original Research rothers et al. MRI and CT of Left Coronary rtery in Children Pediatric Imaging Original Research Julie. rothers 1 Kevin K. Whitehead 1 Marc S. Keller 2 Mark. Fogel 1,2 Stephen M. Paridon 1 Paul M. Weinberg 1,2,3 Matthew. Harris 1,2 rothers J, Whitehead KK, Keller MS, et al. Keywords: anomalous aortic origin of the coronary artery (OC), anomalous coronary artery, congenital heart defects, CT, MRI, pediatrics DOI: /JR Received pril 3, 2014; accepted after revision May 12, Department of Pediatrics, Division of Cardiology, Children s Hospital of Philadelphia and Perelman School of Medicine at the University of Pennsylvania, 34th and Civic Center lvd, 8th Fl, Philadelphia, P ddress correspondence to J.. rothers (brothersj@ .chop.edu). 2 Department of Radiology, Children s Hospital of Philadelphia and Perelman School of Medicine at the University of Pennsylvania, Philadelphia, P. 3 Department of Pathology, Children s Hospital of Philadelphia and Perelman School of Medicine at the University of Pennsylvania, Philadelphia, P. WE This is a web exclusive article. JR 2015; 204:W104 W X/15/2041 W104 merican Roentgen Ray Society Cardiac MRI and CT: Differentiation of Normal Ostium and Intraseptal Course From Slitlike Ostium and Interarterial Course in nomalous Left Coronary rtery in Children OJECTIVE. nomalous left coronary artery from the inappropriate aortic sinus with intraseptal course is generally benign but can be confused on imaging studies with the potentially lethal interarterial, intramural anomalous left coronary artery. The purpose of this study was to assess normal ostial morphologic features and intraseptal course using cardiac MRI and CT in pediatric patients with intraseptal anomalous left coronary artery. MTERILS ND METHODS. retrospective review was conducted of the medical records of 14 children with the diagnosis of intraseptal anomalous left coronary artery between November 2009 and March Coronary artery origin and course were evaluated with cardiac MRI or CT, and 3D assessment of coronary ostial morphologic features was performed with virtual angioscopy. RESULTS. The patient ages ranged from 5 to 18 years at diagnosis; 10 (71.4%) were boys. The right and left coronary origins were the right sinus of Valsalva as a common origin (n = 9) or a single coronary artery (n = 5). nomalous intraseptal left main coronary was found in 13 patients, and one patient had anomalous left anterior descending with retroaortic circumflex coronary artery. nomalous coronary ostia were round and without stenosis in all studies. The anomalous vessel was identified with echocardiography, but the anomalous left coronary artery was not delineated, and a normal ostium was not adequately portrayed in any instance. CONCLUSION. y use of cardiac MRI and CT, the anomalous course of round coronary ostia was confirmed and visualized in a pediatric cohort with intraseptal anomalous left coronary artery. The data provide the basis for understanding the benign clinical course and showing that surgery is unnecessary for this coronary anomaly. T he population prevalence of anomalous aortic origin of the left coronary artery (LC) from the right sinus of Valsalva (left anomalous aortic origin of the coronary artery [OC]) ranges from 0.017% to 0.15% [1, 2]. The two left OC subtypes encountered most frequently in the absence of congenital heart disease are course between the ascending aorta and pulmonary trunk superior to the pulmonary valve (interarterial) and course within the ventricular septum caudal to the pulmonary valve (intraseptal, intraconal, or intramyocardial). The former is often associated with an intramural course and slitlike orifice representing ostial stenosis as well as increased risk of sudden death of the young [3 5]. The latter is generally benign [6, 7]. However, the two subtypes are often confused on imaging studies [8, 9]. The description of the ostium and course of the anomalous vessel must be accurate because the diagnosis of interarterial, intramural left OC can lead to life-altering treatment recommendations, including exercise restriction and surgery. The use of cardiac MRI and contrast-enhanced CT for delineating the sinus of origin and proximal course of anomalous coronary arteries is well documented [9 11]. However, no literature to date, to our knowledge, has described intraseptal left OC in children as assessed with MRI and CT. In our study, we used a novel technique, virtual angioscopy (V) of MR and CT images, to better image the anomalous coronary ostia. We sought to evaluate MRI and CT in a series of children with intraseptal left OC using V to visualize normal ostial morphologic findings and thereby to differentiate this benign condition from the potentially lethal interarterial, intramural left OC and avoid unnecessary intraoperative inspection to confirm normal ostia. W104 JR:204, January 2015

2 MRI and CT of Left Coronary rtery in Children TLE 1: Results of Evaluation of Patients With nomalous Left Coronary rtery With Intraseptal Course ge (y) Sex Reason for Presentation Echocardiography Materials and Methods Study approval was granted by our institutional review board, and a waiver of informed consent was obtained. Data were collected on 14 consecutively registered children with the diagnosis of intraseptal left OC who underwent MRI or CT between November 2009 and March Medical records were retrospectively reviewed for subject presentation and testing used to evaluate the coronary anomaly. Five subjects underwent MRI at our institution; the other studies were obtained at referring institutions and reviewed by the study authors for second opinion. ecause the study was retrospective, the decisions to use MRI versus CT and to use anesthesia were made by the primary cardiologist. MRI and coronary CT angiography were performed with 3D dataset acquisition. ll 3D datasets were adequate for interpretation. MRI studies were performed with 1.5-T systems. MRI was performed with ECG and diaphragmatic gating without administration of a contrast agent. CT angiography achieved coronary enhancement by use of an iodinated contrast agent with ionizing radiation. Each coronary artery sinus of origin and proximal course were reviewed by use of multiplanar reconstruction software, which allowed reformatting the 3D dataset to produce any 2D slice plane. Exercise Stress Test Stress Echocardiography, Myocardial Perfusion Scan V was used to directly evaluate the coronary ostia and determine their proximity to the intercoronary commissure. V has been previously described for coronary artery evaluation [12, 13] and used for visualizing coronary ostial shape and location in patients with interarterial, intramural left OC [14] (Fig. 1). The V software is commercially available and resident on a Leonardo satellite workstation (Siemens Healthcare) in our radiology department. In V, the 3D coronary imaging dataset simulates the perspective from which a surgeon or pathologist would observe the coronary artery origin from within the aortic sinuses. The V camera is positioned centrally in the aorta and focused perpendicular to the plane of the ostium to assess ostial shape (e.g., round or crescentic) and ostial position relative to the intercoronary commissure. Results The patient ages ranged from 5 to 18 years (mean, 11.7 years; median, 13 years) at the time of MRI or CT; 10 (71.4%) were boys. None had undergone surgery for the coronary anomaly. Table 1 details the reason for the initial echocardiographic examination, presumed origin of the anomalous coronary artery determined at echocardiography, and results of Ostial Shape nomalous LC, a Single RC, Common Origin 5 M Screening echocardiography LC from RSOV Round Single RC 7 M Screening echocardiography LD from RC Round Common 8 F Murmur LC from RSOV Normal Round Common 10 M Murmur LC from RSOV Normal Round Common 10 M Dizziness Single RC Round Single RC 10 M Hypertension LD from RSOV Round Single RC 11 M Kawasaki disease Single RC Normal Round Common 13 F radycardia Single RC Normal Stress echocardiography Round Single RC normal 13 F Palpitations, PVC Likely anomalous LC but images unclear enign PVC Stress echocardiography normal Round Common: LD intraseptal from RC, circumflex retroaortic from RC 14 M Screening echocardiography LD from RC Normal Round Single RC 14 M Screening echocardiography LC from RSOV Normal Round Common 15 F Exertional chest pain LC from RSOV Normal Stress echocardiography Round Common normal 16 M Exertional chest pain LC from RSOV or Round Common single RC 18 F Exertional chest pain LC from RSOV Normal Myocardial perfusion scan normal b Round Common Note Dash ( ) indicates data not available or study not performed. LC = left coronary artery, RC = right coronary artery, RSOV = right sinus of Valsalva, LD = left anterior descending coronary artery, PVC = premature ventricular contractions. a nomalous LC anatomy found at cardiac MRI or CT. b Fixed anterior perfusion defect, thought likely artifact due to breast tissue. No MRI evidence of myocardial scar, as would be expected if true perfusion defect were present. ischemia testing, when available. It also compares the echocardiographic findings with the coronary anatomy identified at MRI or CT as reviewed by the authors. Echocardiography definitively showed that the LC was anomalous in 13 cases (92.9%); however, ostial stenosis was not ruled out or the intraseptal course accurately delineated with echocardiography. t echocardiography among the five subjects with single right coronary artery (RC), this vessel was correctly identified as single in two (40%) patients. In contrast, MRI and CT clearly depicted the origin and intraseptal course in all cases, and V depicted the ostia as round and patent. Three subjects experienced chest pain with exertion, but the symptoms were considered musculoskeletal after further questioning and description of the symptoms. No subjects who underwent provocative exercise testing had evidence of ischemia. Imaging studies (seven MRI, seven CT) were considered adequate for interpretation. fter multiplanar reconstruction, the 2D images produced showed that the RC and LC originated from the right sinus of Valsalva in all subjects. The LC (n = 13) or the left anterior descending coronary artery JR:204, January 2015 W105

3 rothers et al. (LD) (n = 1) coursed within the intraseptal muscle posterior to the right ventricular outflow tract (RVOT). The subject with intraseptal LD had a retroaortic circumflex artery, which coursed posterior and rightward in the opposite direction to the LD. Using V, we noted a common origin (i.e., the carina that divides the RC from the anomalous LC did not reach the interior wall of the aorta) in nine subjects. In these subjects, the anomalous LC ostium originated directly from the right sinus in proximity to the RC. In the other five subjects, a single RC originated from the right sinus and divided into the right and left coronary branches. ll anomalous coronary ostia were round and patent (Figs. 2 and 3 and Video 1). The anomalous ostial locations were distinct and remote from the intercoronary commissure (i.e., not juxtacommisural). We also noted that in left OC with an intraseptal course, the LC does not branch C Fig year-old boy with anomalous aortic origin of left coronary artery (LC) from right sinus of Valsalva (left OC) with interarterial, intramural course., Off-axis transverse multiplanar reconstructed CT image displays aortic sinuses and coronary origins. Coronary ostia cannot be directly visualized, and intercoronary commissure is not well defined. RC = right coronary artery, o = aorta.. Virtual angioscopic image shows aortic sinuses from perspective of ascending aorta. nterior and rightward (yellow), posterior and leftward (green), and posterior and rightward (orange) coronary sinuses and intercoronary commissure (ICC) (purple) are clearly defined. Coronary ostial origins within anterior rightward sinus are marked, including conal branch (asterisk). Location of left OC is juxtacommissural and distant from RC origin. LVOT = left ventricular outflow tract. C, Virtual angioscopic image directly shows coronary ostia, widely patent RC, and crescentic, slitlike origin of left OC. until it traverses the length of the RVOT and reemerges onto the epicardial surface, making the LC appear elongated along the intraseptal course. In contrast, in patients with interarterial, intramural left OC, the LC branching occurs adjacent to the aorta (Fig. 4). Discussion Case reports in the literature describing children and adolescents with intraseptal left OC are limited [3, 15, 16]. None de- Fig year-old girl with anomalous aortic origin of left coronary artery from right sinus of Valsalva with intraseptal left anterior descending artery (LD). and, Transverse () and coronal () off-axis steady-state free precession MR images show origins of right coronary artery (RC) and LD. Retroaortic circumflex and conal branches, which also originate from anterior rightward sinus, are not profiled. shows common origin of RC and LD from right sinus. LD has intraseptal course with path posterior () and inferior () to right ventricular outflow tract (RVOT). VS = ventricular septum, ov = aortic valve, LV = left ventricle, L = left atrium. RV = right ventricle. (Fig. 3 continues on next page) W106 JR:204, January 2015

4 MRI and CT of Left Coronary rtery in Children scribes in great detail the evaluation of the coronary ostial morphologic features in live patients. Using V analysis of MRI and CT, we found, for the first time to our knowledge, that intraseptal left OC has a round orifice, in contradistinction to interarterial left OC, which is associated with a slitlike orifice [3, 4]. Visualizing normal round ostia without stenosis is important for providing support that this anomaly is not a risk factor for sudden death and therefore that intervention is not warranted. Furthermore, MRI and CT clearly delineate the intraseptal course, which is also important in differentiating this anatomic subtype from interarterial, intramural left OC. In our study, transthoracic echocardiography neither defined the coronary ostia nor delineated the course of the anomalous vessel. This modality can be limited by acoustic windows, making accurate diagnosis of anomalous coronary arteries challenging [17]. ecause of their invasive nature, transesophageal echocardiography and cardiac catheterization are not readily used in young patients with anomalous coronary arteries. In addition, catheter C angiography and CT expose children to ionizing radiation [10]. Whenever possible, we recommend assessing coronary anomalies with MRI in accordance with the most recent merican Heart ssociation guidelines [18]. Risk of Sudden Death lthough both left OC with an intraseptal course and left OC with an interarterial course are rare, reports of ischemia in and sudden death of the young generally note only the interarterial, intramural type [3 5]. Though the mechanism of myocardial ischemia in interarterial left OC is unknown, the cases of sudden death are associated with the presence of a slitlike ostium and intramural course [3, 4]. Review of the literature reveals the generally benign nature of intraseptal left OC. We found only three case reports of ischemia or sudden death potentially attributed to this coronary anomaly. Two of the patients were men, and the third was a male infant who experienced myocardial infarction during IV line placement. The infant died of bypass surgery complications D Fig. 2 (continued) 13-year-old girl with anomalous aortic origin of left coronary artery from right sinus of Valsalva with intraseptal left anterior descending artery (LD). C, Virtual angioscopic image from perspective of ascending aorta downward toward aortic sinuses shows right and left noncoronary commissures (black arrows). Large and patent single right coronary ostium (outlined) has distinct and remote location from intercoronary commissure (white arrow). D, Close-up virtual angioscopic image of ostium shows four branch origins of single RC. With virtual angioscopy, each coronary branch was confirmed as patent without stenosis. Circ = circumflex coronary artery. when he was 4 years old. There were no pathology data to review to note the size and shape of the left OC ostium [15]. The 36-year-old man had a history of ventricular tachycardia but no exertional symptoms. He died after falling in a river while clutching his chest, but no arrhythmia was documented [5]. The 42-year-old man experienced resistant ventricular tachycardia and exertional symptoms. He presented with chronic cardiomyopathy and a diminished left ventricular ejection fraction of 35% with global hypokinesia. The authors suggested that the anomalous coronary artery was the cause, but after coronary artery bypass, the patient continued to take medication and had a diminished ejection fraction [19]. Numerous studies have shown the benign nature of intraseptal left OC, including a 2013 case report by Nascimento et al. [20] that described a 57-year-old man with the incidental finding of intraseptal anomalous LD. complete workup revealed no signs of ischemia or hypoperfusion in the LD territory, and the patient did not undergo surgical intervention. Furthermore, autopsy studies specifically fo- Fig year-old boy with anomalous aortic origin of left coronary artery (LC) from right sinus of Valsalva with intraseptal LC., Coronal off-axis multiplanar reconstructed contrast-enhanced CT image shows common origin of right coronary artery (RC) and LC branches and intraseptal LC course. o = aorta, P = pulmonary artery, RV = right ventricle, LV = left ventricle., Virtual angioscopic image directly focuses on right ostium, which appears to be common ostium. Coronary artery branch origins are slightly set back from sinus and are patent without stenosis. JR:204, January 2015 W107

5 rothers et al. cusing on sudden death of the young due to coronary anomalies have not shown death of intraseptal left OC [3 6, 21]. In our study, the subjects who presented with chest pain with exertion did not have evidence of current or past ischemia. The description of chest pain was consistent with musculoskeletal chest pain. Unlike the pain in adults, exertional chest pain in children can be musculoskeletal in nature, is rarely cardiac, and is commonly seen [22]. In our series, all cases of left OC with an intraseptal course had a round, patent ostium without an intramural course. In addition, the location of the anomalous ostium within the right coronary sinus of Valsalva was not juxtacommissural, in contradistinction to what has been described in many cases of interarterial left OC [14]. Management s physicians, we often believe that we need to fix a coronary anomaly, with the assumption that this will lower the risk of sudden death. However, morbidity and mortality are associated with any invasive procedure [23, 24]. On the basis of literature findings and our findings of round ostia and no intramural course, we would not predict exercise-induced ischemia with intraseptal left OC. With no evidence to suggest that a young person with intraseptal left OC is at increased risk of ischemia, we would not recommend surgical intervention or exercise restriction. We expect that by collecting data on larger numbers of children and young adults, as in the multiinstitutional nomalous Coronary rtery Registry of the Congenital Heart Surgeons Society [25], we will improve our understanding of the natural history and management of intraseptal left OC and other anomalous coronary artery subtypes. Study Limitations Our study was limited in that it was retrospective and the images were obtained from different institutions. prospective study using the same imaging modality would give closer to uniform data. However, the images we evaluated were sufficient for obtaining the C Fig. 4 Contrast-enhanced CT coronary angiographic images show differences in branching patterns. and, 11-year-old boy with anomalous aortic origin of left coronary artery (LC) from right sinus of Valsalva (OC) with benign intraseptal course. Coronal off-axis images show proximal LC (black arrowhead) () and, with image slightly angulated anteriorly to show midportion of elongated LC (), its posterior course to right ventricular outflow tract (RVOT) and its reemergence on epicardial surface, branching into left anterior descending (white arrowhead), intermedius (yellow arrowhead), and circumflex (orange arrowhead) arteries. LC branches remotely from aorta (O). P = pulmonary artery. C, 18-year-old man with interarterial, intramural OC. Transverse off-axis image shows captures of contrast material in pulmonary venous and systemic arterial phases. Contrast medium has cleared pulmonary arterial phase, and RVOT is unopacified. Proximal left OC and its interarterial, intramural segment are evident. LC trifurcates close to aorta (O) into LD, intermedius, and circumflex arteries. L = left atrium. data needed. In addition, use of V analysis requires a high-quality 3D dataset to achieve adequate spatial resolution of the coronary ostia with this volume-rendering technique. lthough this dataset can generally be obtained in pediatric patients, we recommend performing these studies in centers that specialize in MRI and CT of the young. third limitation was the small sample size; however, for a rare coronary anomaly, ours is a relatively large series that was made possible because of our institution s generous referral network. Conclusion We report the first, to our knowledge, anatomic analysis of intraseptal left OC in pediatric patients. We found round ostia and confirmed the vessel course and characteristics that differentiate the intraseptal anomaly from the potentially lethal interarterial, intramural left OC, which has a slitlike orifice. Echocardiography was useful in suggesting the presence of an anomalous coronary artery but could not be used to evaluate the ostial structure and exact vessel course. W108 JR:204, January 2015

6 MRI and CT of Left Coronary rtery in Children Our findings highlight the importance of further imaging with MRI or CT to obtain a correct anatomic diagnosis to avoid unnecessary exercise restriction or surgical exploration when the anatomic features do not suggest the need for intervention. References 1. Davis J, Cecchin F, Jones TK, Portman M. Major coronary artery anomalies in a pediatric population: incidence and clinical importance. J m Coll Cardiol 2001; 37: Yamanaka O, Hobbs RE. Coronary artery anomalies in 126,595 patients undergoing coronary arteriography. Cathet Cardiovasc Diagn 1990; 21: Taylor J, Rogan KM, Virmani R. Sudden cardiac death associated with isolated congenital coronary artery anomalies. J m Coll Cardiol 1992; 20: asso C, Maron J, Corrado D, Thiene G. Clinical profile of congenital coronary artery anomalies with origin from the wrong aortic sinus leading to sudden death in young competitive athletes. 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