Huge Coronary Artery Aneurysm Demonstrated by 64-slice MDCT Coronary Angiography: a case report

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1 中華放射醫誌 Chin J Radiol 2007; 32: Huge Coronary Artery Aneurysm Demonstrated by 64-slice MDCT Coronary Angiography: a case report I-Ha Lao Chia-Hui Chen Wen-Sheng Tzeng Yen-Jen Wang 2 Mei-Chun Chou Department of Radiology, Chi-Mei Medical Center, Yung-Kang Campus Department of Radiology 2, Chi-Mei Medical Center, Liou-Ying Campus Coronary artery aneurysm is an uncommon disease. We present a case of an unusual huge saccular coronary aneurysm of the left anterior descending coronary artery detected by 64-slice multi-detector computed tomography (MDCT) coronary angiography, which initially presented as a mediastinal mass on chest X-ray. The true size of the aneurysm would have been underestimated by coronary angiography because it contains substantial thrombus. In our case, the clinical role of MDCT coronary angiography is more superior than the traditional coronary angiography. Coronary artery aneurysm is defined as an abnormally dilated segment with a diameter.5 times greater than the normal adjacent artery segment; and it can be classified as fusiform or saccular []. Coronary artery aneurysms are typically diagnosed on coronary angiography. MDCT technology provides a noninvasive alternative to evaluate the abnormality of coronary artery. We present a case of an unusually huge saccular coronary aneurysm of the left anterior descending coronary artery which would have been underestimated by coronary angiography because it contains substantial thrombus. Case Report Reprint requests to: Dr. Mei-Chun Chou Department of Radiology, Chi-Mei Medical Center, Yung- Kang Campus. No. 90, Chung Hwa Road, Yung-Kang, Tainan 70, Taiwan, R.O.C. A 74-year-old man presented to our emergency room with dyspnea and cough for 2-3 days. He had a history of hepatitis B virus- and hepatitis C virusrelated chronic liver disease, chronic obstructive pulmonary disease (COPD) without regular management, hypertension and cigarette smoking for 40 years. He had no history of diabetes or congestive heart failure. Anteroposterior and lateral views of chest x-ray showed a well-defined mass-like lesion with ringshaped calcification, superimposed with the left heart border and lingual segment (Fig. a, b). A chest CT scan was performed to evaluate the mediastinal lesion. In precontrast CT survey, the lesion showed peripheral calcification and it was of close proximity to the left anterior descending coronary artery (LAD). Thus, computed tomography angiography (CTA) was then performed. Within a single breath-hold, CTA was performed on a 64-slice MDCT scanner (TSX-0A, Aquilion, 64, Toshiba medical systems corporation, Tokyo, Japan) with retrospective ECG gating. A total of 80 milliliters of non-iodinated contrast medium was injected through an antecubital vein at the rate of 4.5 ml/sec and flushed with 40 ml saline.

2 206 Huge LAD aneurysm demonstrated by 64-slice MDCT a b Figures. Anteroposterior supine chest radiograph (Fig. a) and left lateral chest radiograph (Fig. b) shows well-defined mass-like lesion (arrow in a. and b.) with ring-shaped calcification, superimposed at left heart border and lingular. 2a 2b Figure 2. Reconstructed images of threedimensional volume-rendered images show a large saccular LAD coronary aneurysm (arrow) with rim calcification, measuring 4.6X4.6cm in size. The distal LAD is not opacified. Severe artherosclerotic change of the left main coronary artery (asterisk) and LAD are found. The right coronary artery (arrow head in b) is shown. A = aorta, P = pulmonary artery, LA = left atrium. Scan parameters, including 0.5 mm section width, 400 msec gantry rotation time, a tube voltage of 20 kvp, and a tube current of 500 ma were set. The helical scan automatically began when the contrast density in the ascending aorta reached 60 HU. The patient s heart rate was between beats/ min during scanning. Beta-blocker was not used because he was suffering from COPD with acute exacerbation. Reconstructed images of the three-dimensional volume-rendered images and maximum-intensityprojection images at various phases of the cardiac cycle were performed on a workstation (Vitrea 2). These images revealed a huge saccular LAD coronary aneurysm with rim calcification, measuring 4.6 x 4.6cm in size (Fig. 2). The aneurysm contained substantial thrombus and it was only filled with small foci of contrast medium (Fig. 3). The distal LAD was not opacified. Severe artherosclerotic change of the LAD and near-total thrombosis of the aneurysm causing total obliteration of distal LAD was highly suspected. The patient did not received angiography and surgical intervention due to his advanced age, poor medial condition and the absence of symptoms attributed to this large aneurysm. Discussion Coronary artery aneurysms are defined as abnormally dilated segments with a diameter.5 times greater than the normal adjacent artery seg-

3 Huge LAD aneurysm demonstrated by 64-slice MDCT 207 Figure 3. Reconstructed images of maximum-intensityprojection images show a coronary aneurysm (arrow) with rim calcification, communicating with LAD. The aneurysm contained substantial thrombus and it was only filled with small foci of contrast medium. ment, and can be classified as fusiform or saccular according to the morphology []. The Coronary Artery Surgery Study Registry (CASS) showed an angiographic incidence of 4.9% among a group of 20,087 patients []. The CASS study also found that the proximal and middle segments of the right coronary artery were most frequently involved by aneurysmal disease. The next most frequently involved segments were the proximal left anterior descending and circumflex coronary arteries []. Nevertheless, according to Tunick et al, discrete (saccular) aneurysms are more common in the LAD, while ectatic (fusiform) aneurysms are more common in the right coronary artery [2]. Aneurysms of the coronary arteries can be congenital or secondary to arteriosclerosis, inflammatory or infectious diseases (Kawasaki disease, Takayasu disease, systemic lupus erythematosis, or polyarteritis nodosa, endocarditis, syphilis), connective tissue diseases (Marfan s syndrome or Ehlers-Danlos syndrome), metastatic tumors, and blunt trauma to the chest [3, 4, 5]. Coronary aneurysms also have been described after angioplasty [6]. Although giant coronary aneurysms are usually congenital in origin, the relatively advanced age of our patient and his multiple cardiovascular risk factors suggested artherosclerosis as the most probable cause of his aneurysm. According to chest X-ray findings, differential diagnoses of a coronary artery aneurysm include aneurysm of the cardiac chamber, post-traumatic pseudoaneurysms of the ascending aorta or the pulmonary trunk, tumor of the heart or pericardium, and, less likely, thymoma [7]. Most descriptions of large coronary artery aneurysms consist of isolated case reports using coronary angiography, low-detector spiral technology and magnetic resonance imaging (MRI). Coronary angiography remains the standard reference technique for diagnosing coronary aneurysms, but it is invasive. Moreover, coronary angiography may be false negative if the native vessel is occluded [8] and it may underestimate the true size of an aneurysm if the aneurysm contains substantial thrombus. MRI has been shown to be useful in the diagnosis of giant coronary aneurysm [9], with the advantage over computed tomography (CT) of not using ionizing radiation. Nevertheless, the spatial resolution of MRI is inferior in relation to that of 64-slice MDCT, and MRI is not usually available for critical patients. MRI cannot show the typical linear peripheral calcifications of an aneurysm either, which is important for a correct diagnosis. Additionally, MDCT is faster, cheaper, and more available in many medical centers compared to MR imaging. 64-slice MDCT allows a rapid, noninvasive scan, with better spatial resolution and more accurate delineation of the size and shape of an aneurysm. Thin-section or thin-slab axial images provide the primary diagnostic information. 64-slice MDCT also enables high-quality 2D and 3D reformations such as three-dimensional volume-rendered images and maximum-intensity-projection images. These reconstructed images may be valuable in showing spatial relations among the aneurysm, great vessels, and the heart. These images are also useful in providing an estimate of the aneurysm s volume. The extent of thrombus in relation to luminal flow can also be depicted with confidence. Coronary artery aneurysm can be complicated by thrombosis or embolization, with subsequent ischemia and rupture. Congenital aneurysms have been reported to rupture into the pericardial space, causing cardiac tamponade [0], or into the right atrium []. The management varies f rom medical management to stent insertion and surgical ligation. In symptomatic patients, surgical excision and ligation is the procedure of choice [2]. The prognosis for coronary artery aneurysm is controversial. Some

4 208 Huge LAD aneurysm demonstrated by 64-slice MDCT believe that the presence of coronary artery aneurysm has an independent adverse effect on longterm mortality rate [3], while some mention that the prognosis is based on the coronary arthrosclerosis [8]. It has been estimated that coronary artery aneurysm as an independent predictor of mortality has an overall 5-year survival of only 7% [3]. However, the prognosis for large coronary artery aneurysm is still unclear. In our case, the true size of the aneurysm may be underestimated by coronary angiography because it contains substantial thrombus. 64-slice MDCT not only displayed the delineation of the size and shape of the aneurysm but also showed the extent of thrombus and the luminal flow, and gave a better spatial resolution. The patient did not received angiography and surgical intervention due to his advanced age, poor medial condition and the absence of symptoms attributed to this large aneurysm. We are following this patient up conservatively and are planning to repeat CTA in six months. In conclusion, large coronary artery aneurysm is an uncommon lesion that is sometimes associated with obstructive coronary artery disease or sudden death. Coronar y ar ter y aneur ysms are typically diagnosed on coronary angiography. But, MDCT technology provides a noninvasive alternative to evaluate the abnormality of coronary artery. MDCT also appears to be an easy, rapid and reliable technique to confirm the diagnosis and plan treatment. In our case, the clinical role of MDCT coronary angiography is superior to the traditional coronary angiography. References. Swaye PS, Fisher LD, Litwin P, et al. Aneurysmal coronary artery disease. Circulation 983; 67: Tunick PA, Slater J, Kronzon I, Glassman E. Discrete atherosclerotic coronary artery aneurysm: a study of 20 patients. J Am Coll Cardiol 990; 5: M a e h a r a A, M i nt z G S, C a s t a g n a M T, e t a l. Intravascular ultrasound assessment of spontaneous coronary dissection. Am J Cardiol 2002; 89: Kato H, Sugimura T, Akagi T, et al. Long-term consequences of Kawasaki disease. A 0- to 2-year follow-up study of 594 patients. Circulation 996; 94: Sumino H, Kanda T, Sasaki T, et al. Myocardial infarction secondary to coronary aneurysm in systemic lupus erythematosus. An autopsy case. Angiology 995; 46: Rodriguez O, Baim DS. Coronary aneurysms after catheter interventions: an exception to bigger is better. Catheter Cardiovasc Interv 997; 4: Hinterauer L, Roelli H, Goebel N, Steinbrunn W, Senning A. Huge left coronary artery aneurysm associated with multiple arterial aneurysms. Cardiovasc Intervent Radiol 985; 8: Anfinsen OG, Aaberge L, Geiran O, Smith HJ, Aakhaus S: Coronary artery aneurysms mimicking cardiac tumor. Eur J Echocardiogr 2004; 5: Channon KM, Wadsworth S, Bashir Y. Giant coronary artery aneurysm presenting as a mediastinal mass. Am J Cardiol 998; 82: Wan S, LeClerc JL, Vachiery JL, Vincent JL. Cardiac tamponade due to spontaneous rupture of right coronary artery aneurysm. Ann Thorac Surg 996; 62: Abou Eid G, Lang-Lazdunski L, Hvass U, et al. Management of giant coronary artery aneurysm with fistulization into the right atrium. Ann Thorac Surg 993; 56: Pahlavan PS, Niroomand F: Coronary artery aneurysm: a review. Clin Cardiol 2006; 29: Baman TS, Cole JH, Devireddy CM, Sperling LS: Risk factors and outcomes in patients with coronary artery aneurysms. Am J Cardiol 2004; 93:

5 Huge LAD aneurysm demonstrated by 64-slice MDCT 209 以 64 張多切層電腦斷層掃描儀之冠狀動脈血管攝影診斷巨大的冠狀動脈血管瘤 : 病例報告 劉綺霞 陳佳慧 曾文盛 王彥人 2 周美君 奇美醫學中心永康院區放射線部奇美醫學中心柳營院區放射線部 2 冠狀動脈血管瘤是少見的疾病 我們提出一例位於冠狀動脈左前降支的巨大囊狀血管瘤 此病例是以 64 張多切層電腦斷層掃描儀之冠狀動脈血管攝影作診斷 此血管瘤初期在胸部 X 光片呈現出縱膈腔腫塊 這血管瘤含有大量的血栓, 因此其實際大小在傳統的冠狀動脈血管攝影必然會被低估 因此在這案例中, 多切層電腦斷層掃描儀之冠狀動脈血管攝影在臨床上之價值是高於傳統的冠狀動脈血管攝影