대한영상의학회지 2009;60: 관상동맥 CT 혈관촬영술에서죽상판특성 : 관상동맥협착에미치는영향 1 최연희 황윤미 백승연 김유경 목적 : 관상동맥 CT 혈관촬영술에서발견된동맥경화죽상판의 CT 소견을분석하여, 혈관협착정도에따른죽상판특성의차이를알아보고자하였다.

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1 관상동맥 CT 혈관촬영술에서죽상판특성 : 관상동맥협착에미치는영향 1 최연희 황윤미 백승연 김유경 목적 : 관상동맥 CT 혈관촬영술에서발견된동맥경화죽상판의 CT 소견을분석하여, 혈관협착정도에따른죽상판특성의차이를알아보고자하였다. 대상과방법 : 2005년 12월부터 2008년 5월까지관상동맥 CT 혈관촬영술에서동맥경화성관상동맥질환을보였던 239명에서죽상판의위치, 협착정도 ( 경증, < 75% 면적협착 ; 중증, > 75%), 죽상판의유형을기록하고, 협착정도에따른죽상판유형간의빈도와협착정도와석회수치간의관계를분석하였다. 결과 : 239명의환자에서 694개의죽상판이발견되었다. 151명의환자에서 ( 경증협착환자의 57.1%; 중증협착환자의 87.5%) 다발성병변을보였다. 죽상판의유형은비석회화형, 혼합형, 석회화형이각각경증협착환자에서 26.7%, 22.5%, 50.8%, 중증협착환자에서 22.9%, 56.3%, 20.8% 였다. 죽상판은좌전하행동맥근위부에가장자주생겼다. 죽상판에의한혈관협착정도와석회수치는유의한상관관계를보였다. 결론 : 죽상판유형은중증협착에서는혼합형이, 경증협착에서는석회화형이가장많았고, 중증협착을갖는환자대부분이다발성병변을보였다. 석회수치는중증협착을갖는환자에서유의하게높았다. 동맥경화성관상동맥질환은선진국에서성인사망률을높이상판특성을분석하였다. 는주요한원인이며, 우리나라에서도식습관의서구화와생활습관의변화로인한활동량의감소등으로말미암아이환율및대상과방법사망률이빠르게증가하고있다 (1). 죽상동맥경화증은혈관벽손상에대한일련의염증반응으대상로, 조직학적으로는혈관벽내에지방선조 (fatty streak) 로이연구는본원임상시험심사위원회승인하에시행되었다. 시작해서, 지질및괴사조직으로이루어진핵 (core of lipid 2005년 12월부터 2008년 5월까지 CCTA를시행한 692명의 and necrotic tissue) 과이를덮는섬유성모자 (fibrous cap) 환자에서관상동맥경화증을보였던 239명 (38-88세, 평균를갖는연성죽상판 (soft plaque) 을형성하고, 여기에석회화 62.1세 ; 남자 156명, 여자 83명 ) 을대상으로후향적연구를가일어나면서병변이안정화되는것으로알려져있다 (2). 하였다. CCTA를촬영한이유는흉통 (n=115), 흉부불쾌감최근급속한 CT 기술의발달로새롭게대두한관상동맥 CT (n=22), 호흡곤란 (n=13), 빈맥 (n=3), 관상동맥질환과거혈관촬영술 (coronary CT angiography, 이하 CCTA) 은고력 (n=3), 심전도이상 (n=3), 두통 (n=1) 이었고, 나머지 79 식적혈관조영술에비해비침습적방법으로관상동맥의협착명은무증상환자로선별검사목적으로시행하였다. 을진단할수있을뿐아니라, 죽상판내지질이나석회화와같은조직학적특성을알수있어그유용성이강조되고있다 (3- 관상동맥 CT 혈관촬영술프로토콜 5). 모든환자에서 CT를시행하기 1시간전에베타차단제인본연구에서는 CCTA에서발견된동맥경화죽상판의 CT propranolol(pranol, Daewoong, Korea) 20 mg을경구투소견을분석하여, 혈관협착정도에따른석회화와관련된죽여하였고, 1시간후심박동수가계속해서분당 65회이상으로 1 측정되면 20 mg을추가로투여한후시행하였다. 추가적투여이화대학교의과대학영상의학과이논문은 2008년 12 월 22일접수하여 2009년 3월 2일에채택되었음. 후에도심박동수가분당 70회이상으로높게측정되거나부정 411

최연희외 : 관상동맥 CT 혈관촬영술에서죽상판특성 맥을보이는환자에서는 CCTA를시행하지않았다. CT 촬영직전에 nitroglycerin(nitroglycerin, Myung Moon, Korea) 0.6 mg을설하투여하였다.

6 mm, 겐트리회전시간 270 msec, feed 18 mm로석회화영상을촬영하였다. CCTA는후향적심전도동조화를사용하였고, 120 kv, 750 effective mas, 검출기폭조절 (collimation) 64 0.6 mm, 겐트리회전시간 370 msec, pitch 0.24로촬영하였다.

에서심장이횡격막과만나는부위까지포함하였다. 영상재구성은절편두께 0.5-0.6 mm로 60-70% RR 간격에서영상을재구성하여최적의영상을선택하였다.

2 최연희외 : 관상동맥 CT 혈관촬영술에서죽상판특성 맥을보이는환자에서는 CCTA를시행하지않았다. CT 촬영직전에 nitroglycerin(nitroglycerin, Myung Moon, Korea) 0.6 mg을설하투여하였다. CT 촬영은 64-절편다중검출나선형전산화단층촬영기 (Somatom Sensation 64, Siemens Medical Solutions, Germany) 를사용하여영상을얻었다. 조영제주입전에전향적심전도동기화를사용하여 120 kv, 40 mas, 검출기폭조절 (collimation) mm, 겐트리회전시간 270 msec, feed 18 mm로석회화영상을촬영하였다. CCTA는후향적심전도동조화를사용하였고, 120 kv, 750 effective mas, 검출기폭조절 (collimation) mm, 겐트리회전시간 370 msec, pitch 0.24로촬영하였다. 조영제주입은 18 게이지카테터를상완전주와정맥에삽입하여 ml 비이온성조영제 (iohexol, Omnipaque 300, Nycomed; iopamidol, Iopamiro 370, Bracco) 를초당 4-5 ml 속도로주입한후 ml의생리식염수를같은속도로주입하였고, 스캔범위는기관분기부 (carina) 에서심장이횡격막과만나는부위까지포함하였다. 영상재구성은절편두께 mm로 60-70% RR 간격에서영상을재구성하여최적의영상을선택하였다. 영상분석영상분석은 CT 검사당시워크스테이션 (workstation) (Leonardo, Siemens Medical Solutions) 에서최대강도투사 (maximum intensity projection, 이하 MIP), 다평면재구성 (multiplanar reconstruction, 이하 MPR), 곡선다평면재구성 (curved MPR) 기법을이용하여좌주관상동맥, 좌전하행동맥, 우측관상동맥, 좌회선동맥에각각평행및직각방향으로영상을분석하고판독하였다. 의료영상저장전송시스템 (Picture Archiving and Communication System, 이하 PACS) (Infinitt, Korea) 으로영상전송은병변부위를혈관과평행및수직으로확대하여촬영한영상과절편두께 3 mm, 간격 2 mm로구성한각각의관상동맥혈관의수직횡단면영상을 3차원 volume rendering 영상과함께전송하였다. 이번후향적연구에서는 PACS에저장된영상을검사당시판독지결과를참고로하여두명의흉부영상의학과전문의가협의로재분석하였다. 각각의환자에서분절별로죽상판의유무, 혈관협착정도, 죽상판의유형을기록하였다. 죽상판의위치는 1) 좌주관상동맥 (left main coronary artery, 이하 LM), 2) 좌전하행동맥의근위부 (proximal left anterior descending artery, 이하 p-lad), 3) 좌전하행동맥의중간부, 4) 좌전하행동맥의원위부, 5) 좌회선동맥의근위부 (proximal left circumflex artery, 이하 p-lcx), 6) 좌회선동맥의중간부, 7) 좌회선동맥의원위부, 8) 우관상동맥의근위부 (proximal right coronary artery, 이하 p-rca), 9) 우관상동맥의중간부, 10) 우관상동맥의원위부, 11) 기타분절로분류하였다. 죽상판에의한혈관협착정도는면적협착 (area stenosis) 이혈관단면적의 75% 미만이면경증, 75% 이상이면중증으로분류하였다. 면적협착은 PACS 모니터에서혈관협착부와협착직상및직하부의혈관강횡단면적을관심영역 (Region of interest, 이하 ROI) 을이용하여측정한후 (Fig. 1A), [1- 협착부혈관강단면적 2 / ( 협착직상부혈관강단면적 + 협착직하부혈관강단면적 )] 100% 로표시하였다. 협착직상및직하부의혈관이혈관분지등에의해단면적을정확히측정하기어려운경우에는둘중측정가능한부위만을측정하여 (1- 협착부혈관강단면적 / 협착직상혹은직하부혈관강단면적 ) 100% 로표시하였다. 죽상판의유형은석회화정도에따라세개의유형으로분류하였는데, 1) 석회화가전혀없는비석회화형, 2) 석회화와비석회화부분이혼재된혼합형, 3) 완전히석회화된석회화형으로분류하였다. 각각의환자에서가장심한협착을보이는병변을대표병변으로하여경증및중증협착에서죽상판유형별빈도를비교 A B C Fig. 1. A 47-year-old man with hypertension who underwent screening coronary CT angiography. A. Cross-sectional area of vascular lumen was measured by using a region of interest (ROI) on PACS monitor. B, C. Longitudinal (B) and cross-sectional (C) multiplanar reconstruction image of proximal left anterior descending coronary artery show mild stenosis due to noncalcified plaque (arrows). 412

하였고, 또모든죽상판병변의위치, 협착정도, 죽상판유형을분석하였다. 관상동맥석회화를갖는환자를두개의군 : 1) 석회화형죽상판만을갖는군 ; 2) 혼합형죽상판을갖거나비석회화형과석회화형죽상판을함께갖는군으로분류한후, 각군에서경증과중증협착을보이는환자들의평균석회수치를비교하였다.

1), 석회화형죽상판만을보인환자가 103명, 비석회화형과석회화형죽상판을함께갖고있었던환자가 21명이었고, 비석회화형이나석회화형죽상판의유무와상관없이혼합형죽상판을갖고있었던환자가 78명이었다 (Fig. 2). 각각의환자에서가장심한협착을보이는병변을협착정도에따라분류하면 Table 1과같다.

3 하였고, 또모든죽상판병변의위치, 협착정도, 죽상판유형을분석하였다. 관상동맥석회화를갖는환자를두개의군 : 1) 석회화형죽상판만을갖는군 ; 2) 혼합형죽상판을갖거나비석회화형과석회화형죽상판을함께갖는군으로분류한후, 각군에서경증과중증협착을보이는환자들의평균석회수치를비교하였다. 여기서석회화는 130 HU이상으로정의하였고, 석회수치를구하는방법은 Agatston scoring system을따랐다. 협착정도와석회수치간의관계는 two-way ANOVA와 Friedman 검정법을이용하여분석하였다. 결과 239명의환자에서비석회화형죽상판만을보인환자가 37 명 (Fig. 1), 석회화형죽상판만을보인환자가 103명, 비석회화형과석회화형죽상판을함께갖고있었던환자가 21명이었고, 비석회화형이나석회화형죽상판의유무와상관없이혼합형죽상판을갖고있었던환자가 78명이었다 (Fig. 2). 각각의환자에서가장심한협착을보이는병변을협착정도에따라분류하면 Table 1과같다. 151명의환자에서 2개이상의관상동맥분절에죽상판에의한협착을보였는데, 경증, 중증협착환자의각각 57.1%(109/191), 87.5%(42/48) 를차지해서중증협착이있는환자일수록다발성병변이있음을알수있었다 (Fig. 2). 환자가갖는죽상판중가장심한협착을보이는죽상판을협착정도와죽상판유형별로분류했을때, 비석회화형, 혼합형, 석회화형의빈도는경증협착을보이는환자에서는각각 51명 (26.7%), 43명 (22.5%), 97명 (50.8%), 중증협착을보이는환자에서는 11명 (22.9%)(Fig. 3), 27명 (56.3%), 10명 (20.8%) 으로, 경증협착환자일수록석회화형이나비석회화형죽상판의빈도가높았고, 중증협착환자에서는혼합형죽상판의빈도가가장높았다 (Fig. 4). 관상동맥분절별로보면, 죽상판은총 239명의환자의 694 개관상동맥분절에서발견되었다. 각각의죽상판의위치및유형은 Table 2와같다. 비석회화형, 혼합형, 석회화형죽상판이각각 91예 (13.1%), 150예 (21.6%), 453예 (65.3%) 였고, 경증및중증협착이각각 597예 (86.0%), 97예 (14.0%) 였다. 죽상판의가장흔한위치는 p-lad(27.7%) 였고 (Fig. 1), 다음으로 p-rca(13.4%) (Fig. 2, 3), p-lcx(11.0%) 에잘발생하였다. 협착정도와석회수치간의관계를보면, 석회화형죽상판만 Table 1. The Distribution of Each Plaque Type According to the Degree of Stenosis Plaque Type Degree of Stenosis* Mild Severe Total Noncalcified 33 (5) 4 (2) 37 (7)0 Mixed 48 (31) 30 (26) 78 (57) Calcified 95 (58) 8 (8) 103 (66)0 Noncalcified and Calcified 15 (15) 6 (6) 21 (21) Total 191 (109) 48 (42) 239 (151) Note. Noncalcified = patients who had only noncalcified plaques, Mixed = patients who had mixed plaques with or without other type plaques, Calcified = patients who had only calcified plaques, Noncalcified and Calcified = patients who had noncalcified and calcified plaques. * Degree of stenosis represents the most severe stenosis in a patient with multiple segment stenosis. Figures in parentheses are numbers of patients with multiple segment stenosis. A B Fig. 2. A 69-year-old man with chest pain and family history of coronary artery disease. A. Multiplanar reconstruction image of the right coronary artery shows multiple severe stenosis due to mixed (black arrows) or noncalcified plaque (white arrow). B. Coronary angiography reveals multiple severe stenoses through the right coronary artery (arrows), corresponding to the stenoses on CT angiography. 413

최연희외 : 관상동맥 CT 혈관촬영술에서죽상판특성 을갖는환자군에서경증및중증협착을보이는환자들의평균석회수치는각각 322.9+315.9(mean+SD), 2582+1025.1로, 협착정도가높은환자일수록유의하게높은수치를보였다 (p-value < 0.0001).

흡연, 고혈압, 당뇨병, 저밀도지단백의증가와같은여러가지원인으로혈관에손상이일어나면내피세포에기능장애가일어나면서염증반응이일어나게되는데, 초기에는혈중지단백이혈관내피세포에침착하면서지방선조를만들고, 염증반응이진행되면서평활근의이주와증식으로죽상판 의외벽을형성하면서지질과괴사조직으로이루어진핵과이를덮는섬유성모자로구성된연성죽상판을형성한다.

4 최연희외 : 관상동맥 CT 혈관촬영술에서죽상판특성 을갖는환자군에서경증및중증협착을보이는환자들의평균석회수치는각각 (mean+SD), 로, 협착정도가높은환자일수록유의하게높은수치를보였다 (p-value < ). 혼합형죽상판을갖거나비석회화형과석회화형죽상판을함께갖는환자군에서도경증및중증협착을보이는환자들의평균석회수치는각각 , 로중증협착환자에서유의하게높았다 (p-value < ) (Fig. 5). 고찰죽상동맥경화증의병태생리가아직명확히밝혀진것은아니지만, 현재로는혈관손상에대한일련의염증반응으로설명되고있다. 흡연, 고혈압, 당뇨병, 저밀도지단백의증가와같은여러가지원인으로혈관에손상이일어나면내피세포에기능장애가일어나면서염증반응이일어나게되는데, 초기에는혈중지단백이혈관내피세포에침착하면서지방선조를만들고, 염증반응이진행되면서평활근의이주와증식으로죽상판 의외벽을형성하면서지질과괴사조직으로이루어진핵과이를덮는섬유성모자로구성된연성죽상판을형성한다. 죽상판이점차진행되면서평활근세포에의한골기질형성으로석회화가이루어지게되는데, 이는진행의마지막단계로지질이풍부해불안정했던부위에혈전형성에의한상처치유반응으로석회화되면서죽상판은안정성만성병변이된다 (2). 본연구에서비석회화형과혼합형죽상판의빈도를비교하였을때경증협착을보이는환자에서는비석회화형죽상판이높게나타나고, 중증협착환자에서는혼합형죽상판이높게나타나는것은이러한죽상판진행에따른석회화증가를반영한다고할수있겠다. 저자들의연구에서경증협착을갖는환자들에서석회화형죽상판의빈도가다른유형에비해가장높게나타났는데, 여기에속한대부분의환자는크기가작은석회화형죽상판을갖고있어아마도죽상판의크기가중증협착을일으킬정도로커지기전에석회화를통하여안정화된것으로생각된다. 또중증협착환자의 8.3% 는비석회화형죽상판에의한협착이었다는점을고려할때, 죽상판내석회화가일어나는시점이 Table 2. The Location and Plaque Type in Patients with Coronary Artery Disease on Coronary CT Angiography Coronary Artery Segments LM plad mlad dlad plcx mlcx dlcx prca mrca drca Others Total Plaques type Noncalcified Mixed Calcified Total Note. LM = left main coronary artery, plad = proximal segment of left anterior descending artery, mlad = middle segment of left anterior descending artery, dlad = distal segment of left anterior descending artery, plcx = proximal segment of left circumflex artery, mlcx = middle segment of left circumflex artery, dlcx = distal segment of left circumflex artery, prca = proximal segment of right coronary artery, mrca = middle segment of right coronary artery, drca = distal segment of right coronary artery, Others = Other segment A B Fig. 3. A 63-year-old woman with hypertension and diabetes mellitus who underwent coronary CT angiography for screening. A, B. Longitudinal (A) and cross-sectional (B) multiplanar reconstruction image of the middle right coronary artery show severe stenosis due to noncalcified plaque (arrows). 414

5 Fig. 4. The distribution of each plaque type according to the stenosis degree. In patients with mild degree stenosis, noncalcified or calcified plaques are much more common than mixed plaque, but in patients with severe stenosis mixed plaque is the most common type. Noncalcified = patients with a maximum stenosis due to noncalcified plaque, Mixed = patients with a maximum stenosis due to mixed plaque, Calcified = patients with a maximum stenosis due to calcified plaque Fig. 5. The relationship between calcium score and degree of coronary artery stenosis in patients with atherosclerotic coronary disease. The mean calcium score in each group of stenosis shows significant correlation with degree of stenosis in both calcified and mixed group (p < ). Mixed = the group of patients with mixed plaques or with noncalcified and calcified plaques, Calcified = the group of patients who had only calcified plaques 40% 정도에이를때까지도혈관내경이감소되지않다가, 후꼭병변의크기와관계가있는것은아닐것으로생각된다. 기로가면동맥이더이상확장에의해보상하지못하고죽상중증협착에서는병변의진행에따른석회화증가를고려할판이내강내로함입되어혈관이좁아지는것으로알려져있다때석회화형죽상판의빈도가가장높을것으로예상함에도불 (9). 그러나죽상판이만성석회화병변으로진행되면서혈관구하고, 본연구에서는오히려석회화형죽상판의빈도가내경에어떤변화가오는지는아직알려진바가없고, 이를증 20.8% 로다른유형에비해가장낮고혼합형의빈도가명하려면혼합형혹은비석회화죽상판을갖는환자들에서 56.3% 로가장높게나타났다. Feuchtner 등 (6) 의관상동맥 CCTA 혹은혈관초음파 (intravascular ultrasound) 를이용질환이의심되는다양한임상증상을보이는환자들 ( 무증상, 비한오랜기간의추적검사가필요할것으로보인다. 전형적흉통, 안정성및불안정성협심증, 급성관상동맥증후 Choi 등 (10) 은관상동맥질환위험인자를갖는무증상환자군 ) 을대상으로한 CCTA 연구에서도 77.5% 가중증협착인의 4% 에서, Hausleiter 등 (11) 은비전형적증상을보이는관전체죽상판에서비석회화형이 24%, 석회화형이 31%, 혼합상동맥질환이의심되는환자의 6.2% 에서비석회화형죽상판형이 45% 으로나타나중증협착에서혼합형의빈도가가장이있었다고보고하였다. 본연구에서도 CCTA를시행한주로높고, 석회화형의빈도는낮은저자들의연구와유사한결과를무증상고위험군혹은비전형적증상을보인환자의 5.3% 에보였다. 서비석회화형죽상판을가지고있었고, 이중소수에서는중이러한분포를보이는이유로는대상환자의구성을생각해증협착을보였다. 비석회화형죽상판은그크기와관계없이볼수있다. 안정성협심증 (stable angina pectoris) 환자가파열과혈전형성에의해급성관상동맥증후군을일으킬수있불안정성협심증이나급성관상동맥증후군환자들에비해죽으므로경증협착을갖는무증상환자일지라도그진단이중상판내석회화양이많고 (7, 8) 주로만성석회화형죽상판에요하다 (6). 이러한점들을고려할때현재사용되고있는관상의한다는점등을고려할때 (6), 연구대상에안정성협심증동맥석회수치는선별검사로서제한점이있고, 앞으로 CCTA 환자들이많이포함될수록석회화형죽상판의빈도도늘어날가선별검사로유용할것으로생각한다. 것으로예상한다. 또반대로저자와 Feuchtner 등 (6) 의연구관상동맥석회수치는그환자가가진죽상판전체양과밀접결과를고려할때중증협착성관상동맥질환을갖는전체환자한상관관계를보이고, 관상동맥협착의정도와도관련이있는에서만성석회화병변에의한안정성협심증이차지하는비율것으로알려져있다 (12-14). 본연구에서도석회화형군및혼이높지않고, 중증협착을일으킬정도의큰혼합형이나비석합형군모두에서석회수치는경증협착보다중증협착에서유회화형죽상판이완전히석회화되기까지는매우오랜기간이의한차이를보이며증가하는것을볼수있었다. 그러나주로필요하다는것을의미할수도있다. 또다른이유로는죽상판석회화형죽상판을갖는환자는경증혈관협착이있더라도높의석회화가진행됨에따라죽상판크기가줄어들어협착의정은석회수치를보일수있고, 반대로주로비석회화형혹은혼도가감소하였을가능성도생각해볼수있다. 죽상판을형성합형죽상판을갖는환자는중증협착이있더라도상대적으로하는과정에서초기에는보상적인혈관확장 (positive 낮은석회수치를보일수있으므로, 모든환자에서석회수치가 remodeling) 이일어나죽상판에의한혈관면적협착이약꼭죽상판양이나혈관협착과비례하는것은아니다. 415

6 최연희외 : 관상동맥 CT 혈관촬영술에서죽상판특성 본연구의제한점은첫째, 본연구의대상이전형적인증상을보이는관상동맥질환환자가아니고주로 CCTA의적응증인무증상고위험군환자및비전형적흉통을보이는환자들이어서협착정도나죽상판의유형별분포가전형적인증상을보이는관상동맥질환환자들과는차이가있을수있다. 둘째, CCTA에서석회화형죽상판에의한협착은과대평가될수있으므로 (15) 본연구결과에서중증협착으로분류된석회화죽상판의일부는경증협착일가능성이있다. 그러나석회화형죽상판의빈도가경증협착에서가장높고, 중증협착에서가장낮다는저자들의연구결과에는변화가없을것으로생각된다. 결론적으로, CCTA를시행한환자들에서경증협착에서는석회화형죽상판의빈도가가장높았고, 비석회화형이혼합형에비해많았으며, 중증협착에서는혼합형죽상판의빈도가가장높았다. 중증협착을갖는환자대부분이다발성병변을보였고, 석회수치는같은협착정도에서는혼합형에비해석회화형죽상판환자들에서높았지만, 혼합형및석회화형모두에서경증협착에비해중증협착에서높은수치를보였다. 참고문헌 1. Beaglehole R. Global cardiovascular disease prevention: time to get serious. Lancet 2001;358: Falk E, Shah P, Fuster V. Coronary plaque disruption. Circulation 1995;92: Achenbach S, Moselewski F, Ropers D, Ferencik M, Hoffmann U, MacNeill B, et al. Detection of calcified and noncalcified coronary atherosclerotic plaque by contrast-enhanced, submillimeter multidetector spiral computed tomography: a segment-based comparison with intravascular ultrasound. Circulation 2004;109: Leber A, Knez A, Becker A, Becker C, von Ziegler F, Nikolaou K, et al. Accuracy of multidetector spiral computed tomography in identifying and differentiating the composition of coronary atherosclerotic plaques: a comparative study with intracoronary ultrasound. J Am Coll Cardiol 2004;43: Myerburg RJ, Interian A Jr, Mitrani RM, Kessler KM, Castellanos A. Frequency of sudden cardiac death and profiles of risk. Am J Cardiol 1997;80:10F-19F 6. Feuchtner G, Postel T, Weidinger F, Frick M, Alber H, Dichtl W, et al. Is there a relation between non-calcifying coronary plaques and acute coronary syndromes? A retrospective study using multislice computed tomography. Cardiology 2008;110: Motoyama S, Kondo T, Sarai M, Sugiura A, Harigaya H, Sato T et al. Multislice computed tomographic characteristics of coronary lesions in acute coronary syndromes. J Am Coll Cardiol 2007;50: Shemesh J, Stroh C, Tenenbaum A, Hod H, Boyko V, Fisman EZ. Comparison of coronary calcium in stable angina pectoris and in first acute myocardial infarction utilizing double helical computerized tomography. Am J Cardiol 1998;81: Glagov S, Weisenberg E, Zarins CK, Stankunavicius R, Kolettis GJ. Compensatory enlargement of human atherosclerotic coronary arteries. N Engl J Med 1987;316: Choi EK, Choi SI, Rivera JJ, Nasir K, Chang SA, Chun EJ, et al. Coronary computed tomography angiography as a screening tool for the detection of occult coronary artery disease in asymptomatic individuals. J Am Coll Cardiol 2008;52: Hausleiter J, Meyer T, Hadamitzky M, Kastrati A, Martinoff S, Schömig A. Prevalence of noncalcified coronary plaques by 64- slice computed tomography in patients with an intermediate risk for significant coronary artery disease. J Am Coll Cardiol 2006;48: Rumberger J, Simons D, Fitzpatrick L, Sheedy P, Schwartz R. Coronary artery calcium area by electron-beam computed tomography and coronary atherosclerotic plaque area. A histopathologic correlative study. Circulation 1995;92: Sangiorgi G, Rumberger J, Severson A, Edwards WD, Gregoire J, Fitzpatrick LA, et al. Arterial calcification and not lumen stenosis is highly correlated with atherosclerotic plaque burden in humans: a histologic study of 723 coronary artery segments using nondecalcifying methodology. J Am Coll Cardiol 1998;31: Detrano R, Hsiai T, Wang S, Puentes G, Fallavollita J, Shields P, et al. Prognostic value of coronary calcification and angiographic stenoses in patients undergoing coronary angiography. J Am Coll Cardiol 1996;27: Zhang S, Levin DC, Halpern EJ, Fischman D, Savage M, Walinsky P. Accuracy of MDCT in assesing the degree of stenosis caused by calcified coronary artery palques. AJR Am J Roentgenol 2008;191:

7 J Korean Soc Radiol 2009;60: Plaque Characteristics on Coronary CT Angiography: Effects on the Degree of Coronary Artery Stenosis 1 Yeon Hee Choi, M.D., Yunmi Hwang, M.D., Seung Yon Baek, M.D., Yookyung Kim, M.D. 1 Department of Radiology, School of Medicine, Ewha Womans University Purpose: We evaluated the CT characteristics of atherosclerotic coronary plaques in relation to the degree of stenosis. Materials and Methods: We analyzed coronary CT angiography of 239 patients showing plaques obtained from December 2005 to May 2008, in terms of degree of stenosis (mild < 75% area stenosis; severe >75%), location of plaque, plaque types, and calcium score. Results: Total 694 segments were found to have plaque in 239 patients. Multiple lesions were found in 151 patients (57.1% of patients with mild stenosis; 87.5% with severe stenosis). The type of plaque was classified into noncalcified, mixed, and calcified in 26.7%, 22.5%, 50.8% of patients with mild stenosis and 22.9%, 56.3%, 20.8% with severe stenosis, respectively. The most common plaque location was the proximal left anterior descending artery. In patients with calcified or mixed plaques, there was a significant correlation between degree of stenosis and calcium score. Conclusion: Mixed plaque was the most common type in severe stenosis, while calcified plaque was the most common in mild stenosis. Multiple lesions were found in most patients with severe stenosis. The calcium score was significantly higher in patients with severe stenosis. Index words : Coronary artery diseases Tomography, X-ray computed Address reprint requests to : Yookyung Kim, M.D., Department of Radiology, Ewha Womans University Mokdong Hospital 911-1, Mokdong, Yancheon-gu, Seoul , Korea. Tel Fax yookkim@ewha.ac.kr 417

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