대한내과학회지 : 제 76 권제 4 호 2009 64 열다중검출 CT 를이용한관상동맥스텐트재협착의평가 경상대학교의과대학 1 내과학교실, 2 영상의학교실, 3 경상건강연구원서명기 1 고진신 1 박소라 1 강영란 1 강민경 1 조정현 1 안연정 1 최봉룡 1,3 정영훈 1,3 곽충환 1,3 최호철 2,3 전경녀 2,3 황진용 1,3 Assessing stent restenosis using 64-multidetector computed tomography coronary angiography Myung-Ki Seo, M.D. 1, Jin-Shin Kho, M.D. 1, So-Ra Park, M.D. 1, Young-Ran Kwang, M.D. 1, Min-Kyeng Kang, M.D. 1, Jung-Hyun Cho, M.D. 1, Youn-Jung An, M.D. 1, Bong-Ryong Choi, M.D. 1,3, Young-Hoon Jeong, M.D. 1,3, Choong-Hwan Kwak, M.D. 1,3, Ho-Cheol Choi, M.D. 2,3, Kyung-Nyeo Jeon, M.D. 2,3 and Jin-Yong Hwang, M.D. 1,3 Departments of 1 Internal Medicine, 2 Radiology and 3 Gyeongsang Institute of Health, College of Medicine, Gyeongsang National University, Jinju, Korea Background/Aims: Multidetector computed tomography (MDCT) is considered to be a noninvasive, alternative method for evaluating stent restenosis. However, the diagnostic accuracy of 16-channel MDCT for stent stenosis is reported to have severe limitations because of high-attenuation stent-related artifacts. 64-channel MDCT, which recently became available in clinical practice, has better spatial and temporal resolution than 16-channel MDCT. The diagnostic accuracy of 64-channel MDCT for stent restenosis (in-segment and in-stent) was assessed by comparing it with conventional coronary angiography. Methods: In-segment and in-stent restenosis ( 50% in diameter) were evaluated in 96 stent segments in 68 patients [61±12 years, 51 (75%) male] using both 64-channel MDCT and conventional coronary angiography. The in-stent analysis was confined to the portion of the artery covered by the stent and the in-segment analysis included the stent and 5 mm proximal or distal to the stent edges. Results: The 64-channel MDCT could evaluate stent restenosis in 93 of 96 (97%) stent segments. Quantitative conventional coronary angiography found in-segment restenosis ( 50% in diameter) in 16 of 68 (23%) patients and 16 of 96 (17%) segments. For the patients with interpretable stent segments, the sensitivity, specificity, positive predictive value, and negative predictive value of 64-channel MDCT for in-segment restenosis per patient were 63, 96, 83, and 89%, respectively; per segment they were 63, 97, 83, and 93%, respectively; and for in-stent restenosis per stent they were 82, 98, 82, and 98%, respectively. Conclusions: The diagnostic accuracy of 64-channel MDCT for assessing stent restenosis had high specificity and negative pre- Received: 2008. 4. 15 Accepted: 2008. 10. 27 Correspondence to Jin-Yong Hwang, M.D. 1 and Kyung-Nyeo Jeon, M.D. 2, Department of 1 Internal Medicine and 2 Radiology, Gyeongsang National University, 90, Chilam-dong, Jinju-si, Gyeongsangnamdo 660-702, Korea E-mail: jyhwang@gnu.ac.kr and knjeon@gnu.ac.kr - 434 -
- Myung-Ki, Seo, et al. Assessment of stent restenosis by 64-MDCT - dictive value in the clinical setting. The 64-channel MDCT may be a promising, less-invasive imaging tool for stent restenosis, especially for the purpose of excluding stent restenosis. (Korean J Med 76:434-442, 2009) Key Words: Coronary restenosis; Computed tomography 서론관동맥풍선성형술과비교하여스텐트삽입술은재협착의빈도가현격히줄어들어관상동맥질환의치료에널리이용되고있다. 그러나스텐트삽입후재협착률은일반스텐트가 20~25%, 약물용출성스텐트가 5~10% 로보고되고있다 1). 현재관상동맥스텐트를삽입한환자에서스텐트삽입부위의협착여부와정도는관상동맥조영술로진단하고있다. 그러나고식적인관상동맥조영술은우수한공간및시간해상능과관상동맥전체를체계적으로검사할수있다는장점에도불구하고, 검사방법자체의침습성으로적은빈도지만심근경색이나뇌졸증, 심부정맥, 대동맥박리및천공등의심대한합병증의가능성이있고, 시술을위하여짧은기간이나마경과관찰을위한입원기간이필요하기때문에임상에서사용에제한이있다 2). 비침습적이고, 빠른시간에관상동맥스텐트의재협착을알수있는진단도구가필요하지만최근까지만족스럽게스텐트협착부위의관상동맥의형태를알수있는비침습적방법이제시되지못하였다. 그동안다중검출컴퓨터단층촬영기 (multidetector computed tomography, MDCT) 를사용한자연관상동맥협착의진단은많은발전이있어민감도와특이도가 90% 이상으로보고되고있으나 3-5), 스텐트협착에대한평가는스텐트의금속재질때문에일어나는고밀도인공물로스텐트의내강을판별하는데제한이있었다 6). 16열-MDCT 를이용한연구들이보고되었으나민감도와특이도는낮게보고되었다 7-12). 그러나최근에도입된 64열-MDCT 는이전의 16열-MDCT 에비하여영상획득속도의비약적인향상으로시간해상능이향상되고단위당영상획득수가증가됨에따라공간해상능이향상되어임상에서활용이많아지고있으며스텐트의협착의평가에서도 16열-MDCT 보다높은진단적정확도를보여줄것으로기대되고있다 13-16). 따라서저자들은고식적관상동맥조영과비교하여최근에도입된 64열-MDCT 가스텐트재협착평가의진단적정확성을연구분석하여보고하는바이다. 대상및방법 1. 연구대상연구대상기준은 2006년 1월에서 2007년 10월까지경상대학교병원에서기존에관상동맥질환이있어서스텐트삽입을한환자들로서재협착이의심되어서고식적관상동맥조영술및 64열-MDCT 를 7일이내에같이시행한환자의영상을후향적으로분석하였다. 검사가시행되기전모든환자에게사전동의서를작성하였고, 신기능장애가있는사람 (creatinine 1.5) 이나과거조영제에이상반응이있었던사람, 우회로에스텐트가삽입된경우는제외하도록하였다. 이런기준을만족한 72명의환자에서검사를시행하였고, 관상동맥조영술사진이분석대상스텐트를평가할수없었던 4명을배제하여최종적으로 68명의관상동맥조영술영상과 64열-MDCT 영상을분석하였다. 64열-MDCT 와고식적관상동맥혈관조영술시행간의간격은당일같이찍은경우와최대 5일로평균 1.25±3일이었다. 총삽입된스텐트수는 113개였으나그중 17개의분절은 2개를연속하여삽입하였는데, 이를 1분절로환산하여분석한스텐트분절수는 96개였다. 또한 2개연속삽입분절의스텐트크기는작은크기의것을기준으로하였다. 이는임상에서각스텐트보다는삽입분절전체의협착유무가더중요하기때문에스텐트가 2개이지만한개의분절로분석하였고, MDCT가작은크기의스텐트를평가하기가더어려울것이라는가정하에작은스텐트의크기를기준으로하였다. 2. 고식적관상동맥조영술관상동맥조영술은일반적인 Judkin s 방법으로시행하였고, 조영술영상은 Siemens 사의 Multistar Plus/T.O.P TM 를이용하여얻어진영상이었다. 계측평가는 Siemens사의 Polytron/ T.O.P TM 를이용한계측및거리측정으로정량적관상동맥조영 (quantitative coronary angiography) 을시행하여스텐트삽입분절의협착정도를평가하였다. 이때관상동맥스텐트협착은내경이가장짧게나타난영상에서참고내경과비교하 - 435 -
- 대한내과학회지 : 제 76 권제 4 호통권제 584 호 2009 - 여 50% 이상협착된것으로정의하였고, 그중에서도 스텐트내재협착 은스텐트로덮힌관상동맥부분에서의협착으로정의하였고, 분절내재협착 은스텐트가장자리의전후 5 mm을포함한전체부분에서의협착으로정의하였다. 동맥의분절위치기입은 Modified American Heart Association coronary artery model 17,18) 을기준으로분류하여기록하였다. 3. 64열다중검출컴퓨터단층촬영방법 CT는 Phillips사의 64다중검출기 (Brilliance, Philips Medical Systems, Cleveland, Ohio) 를사용하였으며검출기폭조절은 Pitch는 0.2, Collimation은 64 0.625, 회전시간은 0.4초였고, 두께는 0.67 mm로기관분지부부터횡격막까지영상을얻었다. 전체촬영시간은 9.187초로설정되었다. 사용된조영제는 Iomeprol (Iomeron 400, Bracco, Milan, Italy) 로, 초당 5 cc로조영제 80 ml를주입후같은속도로생리식염수 50 ml를정맥으로주입하였다. 심박수가 70회 / 분이초과하는경우 1시간전에 propranolol 40 mg을복용시킨후심박수가 70/ 분이하일때검사를시행하였다. 평균심박수는 63/ 분이었으며환자의평균방사선피폭량은 18.2 msv로측정되었다. 4. 64열다중검출컴퓨터단층촬영영상의분석과재건 MDCT 영상의분석은동일회사에서제공된 workstation (Philips Extended Brilliance Workspace, Cleveland, Ohio) 에서분석하였다. 후향적동조화기법 (retrospective gating technique) 을사용하여 75% RR간격에서영상을재구성하여평가한뒤, 최적의영상이아닐때는다른 RR간격에서재구성하여평가하였다. 재건된영상은여러개의형태로분석하였는데즉, 원래의장축방향의단면영상, 경사진여러층의단면을재형성한영상과그에따른혈관과수직인단면영상을종합하여평가하였다. 스텐트재협착평가는먼저육안적으로판단하였는데스텐트내강의밀도가전체적으로근위부혈관의밀도보다낮거나원위부에조영제흐름이단절되었을때완전폐색으로정의하고스텐트내부에비중심성의낮은밀도나주변부에환상으로낮은밀도가보일때부분협착으로판단하고협착정도를측정하였다. 육안적으로판단하기힘든경우스텐트부위의단면영상과근위부혈관의단면영상에서조영증강정도를 HU (Hounsfield Unit) 로측정, 비교하여재협착유무를판단하였다. 숙련된 2명의영상의학과전문의 ( 전경녀, 최호철 ) 에의하여고식적관상동 맥조영결과를알지못하는상태로후향적으로분석하였고, 의미있는분절내재협착과스텐트내재협착에대한관찰자간의일치도는우수하였고 (kappa=0.87, 0.90), 일치되지않은예는합의에의한결과를최종자료로이용하였다. 64열- MDCT 는일차적으로관상동맥영상의판독가능여부가조사되었고, 그후협착의유무와정도를파악하였다. 64열- MDCT 에서의관상동맥스텐트재협착은관상동맥조영술과같이내경협착이 50% 이상인경우로정의하였다. 관상동맥의분절위치는관상동맥조영의분석과같은것을사용하였다 17,18). 5. 통계적분석본연구에서획득한연속변수 (Continuous variables) 는평균 ± 표준편차로표시하였다. 64열-MDCT 를이용한관상동맥스텐트재협착의진단적정확도는환자별, 총스텐트별로구하였고, 평가가가능하지않은경우는 64열-MDCT 의진단능의실체를정확히평가하기위해재협착이있다고가정했을때와제외했을때를분석하였다. 각각의접근도, 민감도, 특이도, 양성예측도및음성예측도를구하여평가하였다. 또한스텐트크기 (3 mm 이상, 2.75 mm 이하 ) 와스텐트종류 (Taxus TM, Cypher TM ) 에따라구분하여분석하였다. 단, Bare metal stent (BMS) 와 Endeavour TM 스텐트는예수가작아스텐트종류의분석에서제외하였다. 신뢰구간은 efficient-score method 방법으로구하였다. 결과 1. 대상환자의특성분석대상환자 68명의성별분포는남성이 51명 (75%), 여성이 17명이었다. 연령분포는 37세에서 78세였으며평균 61±12세였다. 스텐트삽입당시의임상진단은안정형협십증이 19명 (28%), 급성관상동맥증후군이 49명 (72%) 을차지하였다. 위험인자로고혈압 28명 (43%), 당뇨 23명 (38%) 이었다 ( 표 1). 삽입스텐트의평균크기는 2.96±0.37 mm이었고, 3 mm 이상크기의스텐트분절이 58 (60%), 3.0 mm 이하의스텐트분절이 38 (40%) 이었다. 종류는 Cypher TM 68 (71%), Taxus TM 19 (20%), Endeavor TM 6 (6%) 로약물용출성스텐트가대부분이었고, 일반스텐트가 3 (3%) 을차지하였다. 스텐트분절의위치는우관상동맥 58 (60%), 좌주관상동맥을포함한좌전하행지관상동맥 29 (30%), 좌회선관상동맥 9 (10%) 이었 - 436 -
- 서명기외 12 인. 64-MDCT 를이용한관동맥재협착의진단 - Table 1. Baseline characteristics of the patients n=68 Age (years) 61±12 Male : Female 51:17 (75%:25%) Clinical diagnosis at implantation of stent Stable angina Acute coronary syndrome Risk factor Hypertension Diabetes Stent (n=96) Type Cypher TM Taxus TM Endeavor TM Bare metal stent Location RCA LAD(LM) LCX Size (mean) 3 mm 2.75 mm 2.5 19 (28%) 49 (72%) 28 (41%) 23 (34%) 68 (71%) 19 (20%) 6 ( 6%) 3 ( 3%) 58 (60%) 29 (30%) 9 (10%) 2.96±0.37 mm 58 (60%) 21 (22%) 17 (18%) RCA, right coronary artery; LAD, left anterior descending artery; LCX, left circumflex artery. A B 다 ( 표 1). 2. 고식적관상동맥조영의소견 전체환자중 16/68명 (24%) 에서전체분절중 16/96 (17%) 에서스텐트재협착이관찰되었다. 스텐트전후 5 mm를포함한분절내재협착이 16 (17%) 이었고, 스텐트내재협착은 11 (11%) 이었다. 완전협착이 2/96 (2%) 이었고, 부분협착이 14 (15%) 이었다. 3. 관상동맥조영술과비교한 64열 -MDCT 의진단율 64열-MDCT 검사로 65/68명 (95%) 의환자에서스텐트분절중 93/96 (97%) 에서재협착의평가가가능하였다. 64열- MDCT 의환자별로분석한진단적정확도는다음과같다. 판독가능한환자에서환자별분절내재협착의민감도, 특이도, 양성예측도, 음성예측도는각각 63% (10/16), 96% (47/49), 83% (10/12), 89% (47/53) 였고, 환자별스텐트내재협착은각각 82% (9/11), 96% (55/57), 82% (9/11), 96% (52/54) 이었 C Figure 1. A 44-year-old male with no significant restenosis in the stent in the proximal left anterior descending artery. Volumerendered (A) and multiplanar reconstructed (B) 64-channel MDCT images showed no restenosis in the stent (Taxus 3.5 16 mm) in the proximal left anterior descending artery. Coronary angiography (C) also shows no restenosis. - 437 -
- The Korean Journal of Medicine: Vol. 76, No. 4, 2009 - Table 2. Diagnostic accuracy of 64-channel multidetector computerized tomography for stent restenosis compared with conventional coronary angiography n %(95% CI) Stent-based analysis Within Interpretable stent In-segment restenosis Sensitivity 10/16 63 (52.5-73.5) Specificity 75/77 97 (94.2-99.9) PPV 10/12 83 (71.8-93.1) NPV 75/81 93 (87.8-98.2) In-stent restenosis Sensitivity 9/11 82 (72.0-92.1) Specificity 80/82 98 (94.0-100) PPV 9/11 82 (72.0-92.0) NPV 80/82 98 (94.0-100) All (Including Not interpretable stent) In-segment restenosis Sensitivity 10/16 63 (50.0-76.1) Specificity 75/82 94 (90.1-98.3) PPV 10/15 67 (51.0-92.0) NPV 75/81 93 (89.5-97.3) Patient-based analysis Within Interpretable stent In-segment restenosis Sensitivity 10/16 63 (51.5-62.5) Specificity 47/49 96 (92.7-99.3) PPV 10/12 83 (71.8-93.1) NPV 47/53 89 (81.0-97.0) In-stent restenosis Sensitivity 9/11 82 (72.0-92.1) Specificity 55/57 96 (93.8-98.8) PPV 9/11 82 (72.0-92.1) NPV 52/54 96 (93.6-98.6) ALL (Including Not interpretable stent) In-segment segment Sensitivity 10/16 63 (51.5-62.5) Specificity 47/52 90 (86.7-93.3) PPV 10/15 67 (50.8-83.1) NPV 47/53 89 (81.0-97.0) CI, confidence interval; PPV, positive predictive value; NPV, negative predictive value. A B C Figure 2. A 59-year-old male with significant restenosis in the stent in the mid left anterior descending artery. Volume-rendered (A) and multiplanar reconstructed (B) 64-channel MDCT images showed focal restenosis in the stent (Endeaver 3.5 12 mm) in the mid left anterior descending artery. Coronary angiography (C) also showed focal restenosis in the mid portion of the stent in the same artery (arrow). - 438 -
- Myung-Ki, Seo, et al. Assessment of stent restenosis by 64-MDCT - Table 3. Diagnostic accuracy of 64-channel multidetector computerized tomography for in-segment restenosis according to stent size and type among the interpretable stent segments Sensitivity (%, 95%CI) Specificity (%, 95%CI) PPV (%, 95%CI) NPV (%, 95%CI) Stent diameter 3.0 mm 5/8 (63%, 42.5-82.5%) 49/50 (98%, 96.3-100%) 5/6 (83%, 72.7-92.6%) 49/52 (94%, 88.8-99.3%) < 3.0 mm 5/8 (63%, 42.5-82.5%) 29/30 (97%, 94.5-99.9%) 5/6(83%, 72.7-92.6%) 29/32 (91%, 83.4-98.4%) Stent Type Cypher TM 4/10 (40%, 25,5-44.5%) 60/61 (98%, 76.8-99.2%) 4/5 (80%, 68.4-92.3%) 60/66 (91%, 79.6-100%) Taxus TM 1/2 (50%, 40.0-60.0%) 17/17 (100%) 1/1 (100%) 17/18 (94%, 89.5-99.5%) CI, confidence interval; PPV, positive predictive value; NPV, negative predictive value. A B C Figure 3. A 58-year-old male with total obstruction in the stent in the proximal left anterior descending artery. Volume-rendered (A) and curved multiplanar reconstruction (B) 64-channel MDCT images show no contrast flow below the stent (Cypher 2.5 33 mm) in the proximal left anterior descending artery. Coronary angiography (C) also shows total obstruction of the stent in the same artery. 다. 판독불가능한환자를분절내재협착이있다고판정하여분석한민감도, 특이도, 양성예측도, 음성예측도는각각 63% (10/16), 90% (47/52), 67% (10/15), 89% (47/53) 였다 ( 표 2). 64열-MDCT 의각분절별로분석한진단적정확도는다음과같다. 판독가능한분절내협착의민감도, 특이도, 양성예측도, 음성예측도는각각 63% (10/16), 97% (75/77), 83% (10/12), 93% (75/81) 였고, 스텐트내재협착 은각각 82% (9/11), 98% (80/82), 82% (9/11), 98% (80/82) 로나타났다 ( 표 2, 그림 2). 완전협착이있는경우 [2/96 (2%)] 는 64열-MDCT 로모두진단이가능하였다 ( 그림 3). 판독불가능한분절을재협착이있다고판정하고분석한분절내협착에대한민감도, 특이도, 양성예측도, 음성예측도는각각 63% (10/16), 94% (75/80), 67% (10/15), 93% (75/81) 였다 ( 표 2). - 439 -
- 대한내과학회지 : 제 76 권제 4 호통권제 584 호 2009 - Table 4. Summary of recent results regarding the diagnostic accuracy of 64-channel multidetector computerized tomography for stent restenosis among the interpretable stent segments Gaspar T et al. (2005) Rixe J et al. (2006) Cademartiri F. et al. (2007) Oncel D. et al. (2007) Author No. of CT channel 40 64 64 64 64 No. of patients 65 64 173 30 68 No. of stent 111 102 178 39 96 Interpretability (%) 74 59 92.7 100 97 In-stent restenosis prevalence (%) 20 12 11.2 49 11 sensitivity (%) 63.6 86 95 89 82 specificity (%) 87.6 98 93 95 98 PPV (%) 56.0 86 63.3 94 82 NPV (%) 90.7 98 99.3 90 98 In-segment restenosis prevalence (%) 24 17 sensitivity (%) 74.1 63 specificity (%) 83.3 97 PPV (%) 58.8 83 NPV (%) 90.9 93 PPV, positive predictive value; NPV, negative predictive value. 스텐트크기에따른결과는 3 mm 이상과미만에서각각의민감도와특이도, 양성예측도, 음성예측도는비슷하였으며 Cypher TM 와 Taxus TM 에따라서도비슷한진단율을보였다 ( 표 3). 고찰본연구는스텐트분절의재협착여부를알기위해내원한환자를대상으로최근임상에도입된 64열-MDCT 의진단율을평가한것으로총 96개스텐트분절의재협착에대한진단적특이도와음성예측도가 97% 와 93% 로 40열-MDCT 혹은 64열-MDCT 를이용한다른연구결과와유사한결과였다 ( 표 4) 13-16). 이는고식적인관상동맥조영술을시행하기전에스텐트재협착을배제하는목적으로비침습적인 64열- MDCT 의사용하는것이유용하다는최근의다른연구결과를뒷받침해주는것이다. 스텐트부위를 64열-MDCT 로판별하는데많은기술적발전이이루어졌음에도여전히가장중요한장애는금속망의고강도신호로인해스텐트내강이좁아보이거나거의보이지않는것으로특히관상동맥과같은작은혈관일경우부분용적효과 (partial volume effect) 로혈관내강을판별하기 가더욱어렵다는것이다 2,6,7,19). 16열-MDCT 를이용한한연구결과를 8) 보면내강을판별할수있는경우가 50/65 (77%) 에불과했다. 특히혈관의내경이가장중요해서 143명을대상으로한 16열-MDCT 의연구는스텐트내경이 3.0 mm 이하일경우판독가능률이 51% 였지만 3.0 mm를초과한큰스텐트의경우 81% 를판독할수있었다고한다 9). 이외에도스텐트금속의양, 스텐트망의굵기, 스텐트종류등에의해판독에영향을준다고한다 6-9). 그러나최근에 64열-MDCT 를이용한연구결과는혈관의크기에관계없이 95%, 92.7%, 95% 로높은판독가능률을보여주었다 ( 표 4). 본연구결과도 97% 로높은판독률을보여주었다. 이는 64열-MDCT 가 16열 -MDCT 에비해시간적공간적해상도가향상되었고, 최근에판독자의경험이축적되어영상의판독기술이향상되었기때문으로생각된다. 특히스텐트의크기가크면내강을잘판독할수있지만실제적으로진단에영향을미칠정도가아니었고, 본연구에서도스텐트의크기에따라진단정확도도차이를보이지않았다. 64열-MDCT를이용한 Rixe 등 14) 의연구결과가 59/102 (57%) 의낮은판독률을보였는데이는판독자가작은인공물만보여도판독불가라고연구의기준을엄격하게해서분 - 440 -
- 서명기외 12 인. 64-MDCT 를이용한관동맥재협착의진단 - 석하였기때문으로생각한다. 그러나본연구를포함한좋은판독률을보인연구들은임상에서진단을목적으로진행되어영상인공물이조금보이더라도판독자의판단에서판독이가능하면스텐트재협착을결정하였고, 아주심한영상의왜곡이있을때만판독불가로분석하였기때문이다. 특히본연구의대상자의대부분이약물용출성스텐트를삽입한환자로스텐트재협착이진행된환자를제외하고는비교적협착정도가적기때문에판독이용이했을것으로생각된다. 분절별분석에서분절내협착민감도가 63% 로 Gaspar 등 13) 의 74% 보다약간낮고, 스텐트내협착의민감도는 82% 로다른연구의 86%, 95%, 89% 14-16) 와비슷했고, Gaspar 등 13) 의 63% 에비해서는높았다. 민감도는대상환자의유병률과밀접한관련이있는데, 본연구의스텐트재협착의유병률은다른 Rixe 등 14) 과 Cademartiri 등연구 15) 의 12%, 11.2% 비해 17% 로 Gaspar 등 13) 의 20% 와비슷하다. 이는본연구에서는재협착이의심되는환자들을연구대상으로많이참여시켰기때문이다. 그럼에도본연구의스텐트재협착의민감도가 Gaspar 등 13) 의스텐트재협착의민감도보다우수한것은 Gaspar 등 13) 이사용한 40 channel-mdct 보다는본연구에서사용한 64 channel-mdct 의해상도가높아서진단능을호전시켰음을시사한다. 그러나분절내재협착의민감도가낮거나비슷한것은스텐트삽입부위와자연혈관의경계부위협착진단에는개선이뚜렷하지않음을시사한다. 최근의 64열 -MDCT 를이용한연구에서스텐트내협착의민감도가많이개선되었음을시사하는연구결과들이있지만임상적으로더중요한분절내협착의민감도는중간정도이므로해석에주의가필요하다. 특이도와음성예측률은본연구에서각각 98%, 98% 로높은특이도와음성예측률을보여주었는데이는다른연구들과일치된결과이다. 현재널리사용하는약물용출성스텐트는재협착의빈도가적기때문에불필요한고식적관상동맥조영촬영이 64열-MDCT 로많이감소할수있을것으로기대된다. 특히완전폐색의경우는본연구에서는 2예뿐이었지만정확한진단이되었고, Gaspar 등 13) 의연구에서는협착이심할수록진단율이높았고 Cardemartiri 등 15) 의연구에서도완전폐색 7예는정확히진단되었다. 이는완전폐색및아주심한협착의배제에는특이도가더욱더높을것으로생각된다. 또한특이도가낮은운동부하심전도검사와같은기능적인허혈검사와같이사용하면특이도를증대시킬수있어향후이에대한연구도필요하리라생각된다. 64열-MDCT 는때로는고식적관상동맥조영술보다 7~11 msv의과도한방사선에노출되기는하지만 20,21), SPECT (Single Positron Emission Computed Tomography) 나 PET (positron emission tomography) 과같은방사선동위원소를이용한심장영상검사와비교하면낮거나비슷하다. 그러나혈관의천자및지혈이필요없고빠른시간내에외래에서손쉽게검사할수있는장점을가지고있어향후스텐트삽입후분절내협착의배제에도움이되리라예상이된다. 본연구의한계점은대상환자가다른연구와비슷하지만단일센터의연구이므로환자선택에의한오차가많고연구자의경험과지식에의존적인결과이므로모든센터에서같은결과를기대할수없다는단점이있다. 그리고스텐트협착의유병률은환자별로 24% 스텐트병변별로 17% 로다른연구에비해높았지만전체적으로낮은유병률은진단율을결정하는데중요한제한점이다. 요약목적 : 관상동맥스텐트의재협착을진단하는데있어최근에도입된 64열-MDCT 는기존의 MDCT 과비교하여영상획득속도와공간해상도가향상되어스텐트삽입병변에대한진단에기대를모으고있으나이에대한연구는미미하다. 64 열-MDCT 를이용한 CT 관상동맥혈관조영술을이용하여스텐트재협착을평가하고그진단적정확성을고식적관상동맥조영과비교, 분석하고자한다. 방법 : 관상동맥스텐트를삽입한환자들중 64열-MDCT 와고식적관상동맥조영술을같이시행한 68명의환자의자료를분석하였다. 50% 이상의관상동맥스텐트재협착을진단하는 64열-MDCT 를이용한진단적정확도는환자별, 스텐트분절별로분절내재협착 ( 스텐트근위부와원위부의 5 mm를포함 ) 과스텐트내재협착에대한민감도, 특이도, 양성예측도및음성예측도를각각구하여평가하였다. 결과 : 고식적관상동맥조영술로 16/96 (17%) 개의스텐트분절에서 16/68 (23%) 명의환자에서스텐트분절내재협착 ( 50%) 이발견되었다. 64열-MDCT 로 93/96 (97%) 개의스텐트분절에서재협착의평가가가능하였다. 평가가가능한예에서환자별분석에서 64열-MDCT 의스텐트분절내재협착의민감도, 특이도, 양성예측도, 음성예측도는각각 63% (10/16), 96% (47/49), 83% (10/12), 89% (47/53) 였고, 분절별분석에서스텐트분절내재협착에대한진단적정확도는각각 63% (10/16), 97% (75/77), 83% (10/12), 93% (75/81), 스텐트내재협착에대한진단적정확도는각각 82% (9/11), 98% (80/82), 82 (9/11), 98 (80/82) 이었다. - 441 -
- The Korean Journal of Medicine: Vol. 76, No. 4, 2009 - 결론 : 64열-MDCT 는높은특이도와음성예측도를보이므로스텐트재협착의배제를위해사용할수있는유망한비침습적진단도구가될것이다. 중심단어 : 관상동맥재협착 ; 다중검출컴퓨터단층촬영 REFERENCES 1) Kastrati A, Mehilli J, von Beckerath N, Dibra A, Hausleiter J, Pache J, Schuhlen H, Schmitt C, Dirschinger J, Schomig A. Sirolimus-eluting stent or paclitaxel-eluting stent vs balloon angioplasty for prevention of recurrences in patients with coronary in-stent restenosis: a randomized controlled trial. JAMA 293:165-171, 2005 2) Aruny JE. Complications of coronary arteriography. In: Baum S, eds. Abrams angiography: interventional radiology. 4th ed. p. 572-582, Boston, Little Brown, 1997 3) Schoenhagen P, Halliburton SS, Stillman AE, Kuzmiak SA, Nissen SE, Tuzcu EM, White RD. Noninvasive imaging of coronary arteries: current and future role of multi-detector row CT. Radiology 232:7-17, 2004 4) Nieman K, Cademartiri F, Lemos PA, Raaijmakers R, Pattynama PM, de Feyter PJ. Reliable noninvasive coronary angiography with fast submillimeter multislice spiral computed tomography. Circulation 106:2051-2054, 2002 5) Ropers D, Baum U, Pohle K, Anders K, Ulzheimer S, Ohnesorge B, Schlundt C, Bautz W, Danel WG, Achenbach S. Detection of coronary artery stenoses with thin-slice multi-detector row spiral computed tomography and multiplanar reconstruction. Circulation 107:664-666, 2003 6) Maintz D, Juergens KU, Wichter T, Grude M, Heindel W, Fischbach R. Imaging of coronary artery stents using multislice computed tomography: in vitro evaluation. Eur Radiol 13: 830-835, 2003 7) Nieman K, Oudkerk M, Rensing BJ, van Ooijen P, Munne A, van Geuns RJ, de Feyter PJ. Coronary angiography with multi-slice computed tomography. Lancet 357:599-603, 2001 8) Gilard M, Cornily JC, Rioufol G, Finet G, Pennec PY, Mansourati J, Blanc JJ, Boschat J. Noninvasive assessment of left main coronary stent patency with 16-slice computed tomography. Am J Cardiol 95:110-112, 2005 9) Mollet NR, Cademartiri F, van Mieghem CA, Runza G, McFadden EP, Baks T, Serruys PW, Krestin GP, de Feyter PJ. High-resolution spiral computed tomography coronary angiography in patients referred for diagnostic conventional coronary angiography. Circulation 112:2318-2323, 2005 10) Ohno M, Yoshida A, Miki S, Mizoguchi T, Kohno Y, Matsumae H. Evaluation of in-stent restenosis (ISR) with 16-row multi-detector computed tomography (MDCT). Circ J 68(Suppl 1):404, 2004 11) Seifarth H, Raupach R, Schaller S, Fallenberg EM, Flohr T, Heindel W, Fischbach R, Maintz D. Assessment of coronary artery stents using 16-slice MDCT angiography: evaluation of a dedicated reconstruction kernel and a noise reduction filter. Eur Radiol 15:721-726, 2005 12) Hoffmann U, Hadvar J, Dunn E. Is CT angiography ready for prime time?: a meta-analysis. J Am Coll Cardiol 43(Suppl A):312A, 2004 13) Gaspar T, Halon DA, Lewis BS, Adawi S, Schliamser JE, Rubinshtein R, Flugelman MY, Peled N. Diagnosis of coronary in-stent restenosis with multidetector row spiral computed tomography. J Am Coll Cardiol 46:1573-1579, 2005 14) Rixe J, Achenbach S, Ropers D, Baum U, Kuettner A, Ropers U, Bautz W, Daniel WG, Anders K. Assessment of coronary artery stent restenosis by 64-slice multi-detector computed tomography. Eur Heart J 27:2567-2572, 2006 15) Cademartiri F, Schuijf JD, Pugliese F, Mollet NR, Jukema JW, Maffei E, Kroft LJ, Palumbo A, Ardissino D, Serruys PW, Krestin Sp, van der Wall EE, de Feyter PJ, Bax JJ. Usefulness of 64-slice multislice computed tomography coronary angiography to assess in-stent restenosis. J Am Coll Cardiol 49:2204-2210, 2007 16) Oncel D, Oncel G, Karaca M. Coronary stent patency and in-stent restenosis: determination with 64-section multidetector CT coronary angiography: initial experience. Radiology 242:403-409, 2007 17) American Heart Association Grading Committee. Coronary artery disease reporting system. Circulation 51:31-33, 1975 18) Serruys PW, Unger F, van Hout BA, van den Brand MJ, van Herwerden LA, van Es GA, Bonnier JJ, Simon R, Cremer J, Colombo A, Santoli C, Vandermael M, Marshall PR, Madonna O, Firth BG, Breenan A, Morel MA, Hugenholtz PG. The ARTS study (Arterial Revascularization Therapies Study). Semin Interv Cardiol 4:209-219, 1999 19) Achenbach S, Giesler T, Ropers D, Ulzheimer S, Derlien H, Schulte C, Wenkel E, Moshage W, Bautz W, Daniel WG, Kalender WA, Baum U. Detection of coronary artery stenoses by contrast-enhanced, retrospectively electrocardiographically- gated, multislice spiral computed tomography. Circulation 103: 2535-2538, 2001 20) Siemens A. SOMATOM sensation cardiac 64: application guide. Forchheim, Siemens AG Medical Solutions, 2004 21) Hundt W, Rust F, Stabler A, Wolff H, Suess C, Reiser M. Dose reduction in multislice computed tomography. J Comput Assist Tomogr 29:140-147, 2005-442 -