Journal of Radiation Industry 1 (3) : 155~160 (2007) 상행대동맥의최대조영증강시간과각인자 ( 심박동수, 심박출계수, 체질량계수 ) 와의관계 장영일 정운관 1 동경래 * 광양보건대학방사선과, 1 조선대학교원자력공학과 The Relationships between the Parameters (Heart Rate, Ejection Fraction and BMI) and the Maximum Enhancement Time of Ascending Aorta Young-Ill Jang, Woon-Kwan Jung 1 and Kyeong-Rae Dong* Department of Radiological Technology, Kwangyang Health College 1 Department of Nuclear Energy Technology, Chosun University Abstract - In this study, Bolus Tracking method was used to investigate the parameters affecting the time when contrast media is reached at 100 HU (T 100) and studied the relationship between parameters and T 100 because the time which is reached at aorta through antecubital vein after injecting contrast media is different from person to person. Using 64 MDCT, Cadiac CT, the data were obtained from 100 patients (male: 50, female: 50, age distribution: 21~81, average age: 57.5) during July and September, 2007 by injecting the contrast media at 4 ml sec -1 through their antecubital vein except having difficulties in stopping their breath and having arrhythmia. Using Somatom Sensation Cardiac 64 Siemens, patients height and weight were measured to know their mean Heart rate and BMI. Ejection Fraction was measured using Argus Program at Wizard Workstation. Variances of each parameter were analyzed depending on T 100 s variation with multiple comparison and the correlation of Heart rate, Ejection Fraction and BMI were analyzed, as well. According to T 100 s variation caused by Heart rate, Ejection Fraction and BMI variations, the higher patients Heart Rate and Ejection Fraction were, the faster T 100 s variations caused by Heart Rate and Ejection Fraction were. The lower their Heart Rate and Ejection Fraction were, the slower T 100 s variations were, but T 100 s variations caused by BMI were not affected. In the correlation between T 100 and parameters, Heart Rate (p 0.01) and Ejection Fraction (p 0.05) were significant, but BMI was not significant (p 0.05). In the Heart Rate, Ejection Fraction and BMI depending on Fast (17 sec and less), Medium (18~21 sec), Slow (22 sec and over) Heart Rate was significant at Fast and Slow and Ejection Fraction was significant Fast and Slow as well as Medium and Slow (p 0.05). but BMI was not statistically significant. Of the parameters (Heart Rate, Ejection Fraction and BMI) which would affect T 100, Heart Rate was the most significant. The higher Heart Rate and Ejection Fraction were, the faster T 100 was. Key words : Heart Rate, Ejection Fraction, Body Mass Index * Corresponding author: Kyeong-Rae Dong, Tel. +82-61-760-1459, Fax. +82-61-763-9001, E-mail. krdong@hanmail.net 155
156 장영일 정운관 동경래 서론전산화단층촬영검사 (CT) 가보편적으로시행되고있는데, 최근다중영상컴퓨터촬영기 (multi-detector computed tomography: MDCT) 의발전은체적정보 (volume data) 를얻어일정간격, 또는임의방향으로영상을재구성할수도있고 3차원의영상으로도재구성도가능해졌다 ( 김등2002; 박등2002). 또한전보다짧은시간의검사가가능하기때문에호흡에의한화질저하도줄일수있다. 과거 Single-detector 나선식 CT는주입된조영제의 Bolus속도를 Scan속도가따라갈수없는단점으로인하여초당주입되는조영제량을늘려조영증강예측시간에검사하는방법을사용 (David et al. 1985; Gray 2001) 하였지만, 이제는 Bolus Tracking기법을이용하면조영제주입후원하는부위의농도가가장최적일때검사가가능하게되었다. Bolus Tracking 기법은조영제주입을시작하고선택된단일평면에대한짧은시간간격의모니터링스캔을시행하면서특정한해부학적구조물의조영증강이원하는조영증강정도즉, 역치 (threshold) 에도달했을때진단적스캔으로전환시키는방법이다. 초기 Bolus Tracking (Bae et al. 1998) 은모니터링스캔과진단적스캔사이의전환에필요한시간이상당히길었기때문에 Bolus Tracking 기법을영상획득에적용하기힘들었으나, 소프트웨어와하드웨어가발달되면서가능할수있게되었다. 이에본연구에서는전주정맥 (antecubital vein) 을통해조영제주입후대동맥에도달하는시간이사람마다각각다르게나타난다는점을착안 (Lim et al. 2007; Nobusada et al. 2007) 하여이에 Bolus Tracking기법을이용하여상행대동맥에조영제 가 100 HU에도달하는시간 ( 이하 T 100) 에영향을주는인자들에대해살펴보고그들의상관관계에대해연구해보았다. 연구및방법 1. 연구대상본연구는 2007년 7월부터 9월까지광주지역 C원을내원하여 64 MDCT로 Cardiac CT를검사한환자로부정맥환자, 호흡중지에문제가발생한환자는제외하고전주정맥으로조영제를초당 4ml로주입하여검사한 100명 ( 남자 50명, 여자 50명, 연령분포 21~83세, 평균연령 57.5세 ) 으로하였다. 2. 사용기기 1) 64slices MDCT: Somatom Sensation Cardiac 64 (Siemens Medical system, Erlangen, Germany) 2) Auto injector: EMPOWER CTA (E-Z-EM, New York, USA) 3) Contrast media: Ultravist 370 (Iopromide, Schering, USA) 4) Workstation: Wizard (Siemens Medical system, Erlangen, Germany), Argus Program 3. 검사방법검사전환자의평균심박동수 (Heart Rate: HR) 와체질량지수 (Body Mass Index: BMI) 를알기위해키, 몸무게를측정하였으며, 전주정맥에 20G catheter line을확보 Fig. 1. Bolus tracking of the ascending aorta.
최대조영증강시간과각인자와의관계 157 하고자동주입기를이용하여초당 4ml의속도로조영제를 70 ml 주입한후이어서초당 5ml의속도로생리식염수 60 ml를주입하였다. 상행대동맥에서 Bolus Tracking 실시하여 100 HU되는시점 (Fig. 1) 으로부터 6 초후영상을얻기시작하였으며, 호흡정지하에폐동맥간부터심저까지단면영상을얻었다. Scan parameter는 120 kv, 800~900 mas, 64 0.6 collimation, 0.2 pitch, 0.33 Bolus Tracking Resuslt YU, JUN BAE 16936335 10-Sep-2007 15:00:00 enh [HU] 120 100 80 60 40 20 0 0 5 10 15 20 time [s] Fig. 2. Bolus tracking result. sec rotation time, 0.75 slice thickness, 0.5 mm interval로검사하였으며, 영상재구성과 Bolus Tracking Result (Fig. 2) 는 Wizard workstation을이용하여분석하였다. 4. 연구방법 심박출계수 (Ejection Fraction : EF) 의측정은 Wizard workstation의 Argus Program을이용하여 short axis cine 영상을기준으로하여 5~95% 영상을 5% 간격으로 6 mm thickness와 interval로 8~9 slices를 reconstruction하였고, Argus Program을이용하여확장기말과수축기말을육안으로확인한후, 수작업에의하여관심영역을설정하였다. 또한다음과같은공식 1에의해서각각의심박출계수를측정 (Fig. 3) 하였고, 키와몸무게를이용하여지방의양을측정하는비만측정법인체질량지수 (BMI) 는다음과같은공식 2에의해서각각측정하였다. 통계학적분석은 SPSS (Ver 12.0) 를이용하여 T 100 변화에따른 HR과 EF, BMI에대한상관계수와 T 100 을 Fast (17초이하 ), Medium (18~21초), Slow (22초이상 ) 의구분하여각인자들 (HR, EF, BMI) 을분산분석을실시한후사후분석으로비교분석하였다. Stroke volume ( 심박출량 )=EDV (volume)-esv 식 (1) Stroke volume Ejection Fraction=mmmmmmmmmmmmmmm 100 ( 심박출계수 ) EDV 식 (2) Cardiac Output=Stroke volume 60 sec 식 (3) 체중 (kg) BMI ( 체질량지수 )=mmmmmmmmmmmmmmmmmmmmm 신장 (m) 신장 (m) 식 (4) Fig. 3. Measure method and values of the Ejection Fraction.
158 장영일 정운관 동경래 Table 1. T 100 according to Heart Rate (unit: persons, %) Heart Rate (bpm) ~45 46~50 51~55 56~60 61~65 65~ Total ~14 2 1 2 2 7 (7) 15 1 1 2 (2) 16 2 3 6 1 12 (12) 17 4 8 3 4 1 20 (20) T 100 18 3 5 7 3 1 19 (19) (sec) 19 1 4 3 2 10 (10) 20 2 2 1 1 6 (6) 21 1 3 2 1 1 8 (8) 22 1 1 3 1 6 (6) 23 1 3 4 (4) 24~ 4 2 6 (6) Total 7 (7) 20 (20) 32 (32) 24 (24) 13 (13) 4 (4) 100 (100) Table 2. T 100 according to Ejection Fraction (unit: persons, %) Ejection Fraction ~40 41~50 51~60 61~70 71~ Total ~14 1 4 2 7 (7) 15 1 1 2 (2) 16 3 5 3 1 12 (12) 17 2 13 5 20 (20) T 100 18 1 2 10 6 19 (19) (sec) 19 1 6 2 1 10 (10) 20 6 6 (6) 21 5 3 8 (8) 22 2 2 2 6 (6) 23 2 2 4 (4) 24~ 1 2 2 1 6 (6) Total 4 (4) 15 (15) 54 (54) 25 (25) 2 (2) 100 (100) 70 80 60 70 60 HR 50 EF 50 40 40 30 10 15 20 25 30 35 Fig. 4. T 100 according to Heart Rate. T 100 30 10 15 20 25 30 35 T 100 Fig. 5. T 100 according to Ejection Fraction. 결과및고찰 1. T 100 변화에따른 Heart Rate, Ejection Fraction, BMI (Body Mass Index) 의분포 1) Heart Rate는 51~55 bpm에서가장많은 32명 (32%), T 100 은 17초에서가장많은 20명 (20%) 으로나타났으며, Heart Rate가높을수록 T 100 이빨라지고, Heart Rate가낮을수록 T 100 이늦어지는것으로나타났다 (Table 1, Fig. 4). 2) Ejection Fraction은 51~60에서가장많은 54명 (54%), T 100 은 17초에서가장많은 20명 (20%) 으로나타 났으며, Ejection Fraction이높을수록 T 100 이빨라지고, Ejection Fraction이낮을수록 T 100 이늦어지는것으로나타났다 (Table 2, Fig. 5). 3) BMI는 18.6~22.9에서가장많은 39명 (39%), T 100 은 17초에서가장많은 20명 (20%) 으로나타났으며, BMI에따른일정한 T 100 이나타나지않았다 (Table 3, Fig. 6). 2. Heart Rate, Ejection Fraction, T 100, BMI 에대한관계 T 100 과 Heart Rate, Ejection Fraction, BMI의상관관계는 Heart rate (r=-0.386) 에서뚜렷한음적상관관계 (p 0.01) 를, Ejection Fraction (r=-0.265) 에서약한음적
최대조영증강시간과각인자와의관계 159 Table 3. T 100 according to BMI (unit: persons, %) BMI ~18.5 18.6~22.9 23~24.9 25\29.9 30~ Total ~14 4 1 1 1 7 (7) 15 1 1 2 (2) 16 1 5 3 3 12 (12) 17 1 8 5 4 2 20 (20) T 100 18 2 9 5 2 1 19 (19) (sec) 19 3 2 4 1 10 (10) 20 2 2 2 6 (6) 21 1 4 3 8 (8) 22 4 2 6 (6) 23 1 3 4 (4) 24~ 1 1 4 6 (6) Total 4 (4) 39 (39) 24 (24) 28 (28) 5 (5) 100 (100) 30 Table 4. T 100, Heart Rate, Ejection Fraction, BMI to correlation coefficient T 100 Heart Rate Ejection Fraction BMI T 100 1.000-0.361** -0.236* 0.160 Heart Rate -0.361** 1.000-0.054 0.127 Ejection Fraction -0.236* -0.054 1.000-0.097 BMI 0.160 0.127-0.097 1.000 *p<0.05, **p<0.01 Table 5. T 100 according to Heart Rate, Ejection Fraction, BMI to correlation coefficient (unit: sec, Mean±SD) Fast (~17) Medium (18~21) Slow (22~) F P Heart Rate 55.59±6.14* 54.09±5.424 50.75±8.00* 3.529 0.033 Ejection Fraction 57.30±7.66 57.54±6.40 49.80±9.77 6.899 0.002 BMI 23.61±3.42 23.67±3.22 24.34±2.70 0.313 0.732 *,, 0.05 BMI 25 20 15 10 15 20 25 30 35 Fig. 6. T 100 according to BMI. T 100 상관관계 (p 0.05) 를보였다. 하지만 BMI (r=0.155) 에서는상관관계 (p 0.05) 가나타나지않았다 (Table 4). 3. T 100 구분에따른 Heart Rate, Ejection Fraction, BMI 의관계 Fast (17초이하), Medium (18~21초), Slow (22초이상) 의구분에따른 Heart Rate, Ejection Fraction, BMI에서각각 Heart Rate에서는 Fast와 Slow에서, Ejection Fraction은 Fast와 Slow, Medium과 Slow에서유의 (p 0.05) 하였다. 하지만, BMI (p 0.05) 에서는유의성이없는결과로나타났다 (Table 5). 실제 T 100 은환자의혈액순환속도, 심박동수, 심박출량, 성별, 나이, 체격그리고질병의유무등여러가지 요인에따라개인차가보인다. 본연구는 T 100 에영향을줄수있는인자중심장이혈액을혈관으로내보내기위해수축할때나타나는심장박동으로이에따라일정한영향을예측할수있는심박동수, 일정한주기로수축과팽창을되풀이하며혈액을동맥으로박출하는펌프기능을표현하는심박출계수로수축기말에있어서심장의기능을평가하는가장흔히사용되는변수로서주요인자를선별하였다. 또한, 체내지방량에따라당뇨병, 성인심장병, 담석증, 고혈압등에다양한질병에영향을주는체질량지수 (BMI) 는잠재적질병으로인한영향인자로선별하였고, 그구분은대한비만학회의기준인저체중, 정상, 과체중, 비만, 고도비만으로나누었다 (Josef et al. 1993; Lee et al. 2005; Matthew et al. 2007). 연구전 T 100 에가장큰영향을주는인자로심장의기능적요소인 Ejection Fraction으로예상했지만, 이연구결과에서는 Ejection Fraction은약한상관관계를나타낸반면, Heart Rate는뚜렷한상관관계로나타났다. 이것은혈액을박출하는펌프기능보다심장박동수에더큰영향을받는것으로나타났다. 결론 64 MDCT로 Cardiac CT를시행시조영제를투여에따라 T 100 변화는 Heart Rate와 Ejection Fraction의경우높을수록빨라지고낮을수록늦어졌다. 그러나 BMI에
160 장영일 정운관 동경래 따른 T 100 의영향은나타나지않았다. T 100 과 Heart Rate, Ejection Fraction, Body Mass Index의상관관계는 Heart Rate (p 0.01) 와 Ejection Fraction (p 0.05) 에서유의하였고, BMI (p 0.05) 에서는유의하지않았다. 이연구에서는대상환자의수가 100명으로비교적적은집단이었고, 베타차단제의사용, 전주정맥을통해상행대동맥까지가는과정중상대정맥이나폐동맥, 폐정맥의혈관의문제점이있을경우에대해서는제한점이있었다. 차후더많은대상환자와영향인자들에대한후향적연구가시행된다면 Heart Rate를측정함에따라정상동율동의심박동수와정상범위군의심박출계수의예측이가능할것으로사료된다. 참고문헌 김윤식, 윤인규, 이경숙. 2002. Bolus Triggering 기법을이용한 Delay Time 의적정화. 대한전산화단층기술학회. 4(1): 113-117. 박장흠, 김기홍, 서동수. 2002. SDCT 와 MDCT 를이용한삼차원재구성영상의질의비교. 대한전산화단층기술학회. 4(1):63-71. Awai K, Hiraishi K and Hori S. 2004. Effect of contrast material injection duration and fate on aortic peak time and peak enhancement at dynamic CT involving injection protocol with dose tailored to patient weight. Radiology. 230: 142. Bae KT, Heiken JP and Brink JA. 1998. Aortic and hepatic peak enhancement at CT: effect of contrast medium injection rate-pharmacokinetic analysis and experimental porcine model. Radiology. 206:455. Booth DC, Nissen S and DeMaria AN. 1985. Assessment of the severity of valvular regurgitation by digital subtraction angiography compared to cineangiography. Am. Heart J. 110(2) :409-416. Funabashi N, Suzuki K, Terao M, Maeda F, Nakamura K, Mita Y, Asano M, Kudo M, Suzuki K, Kurokawa M and Ko-muro I. 2007. New acquisition method to exclusively enh-ance the left side of the heart by a small amount of contrast material achieved by multislice computed tomography with 64 data acquisition system. Int. J. Cardiol. 114(2):265-269. Grohs JG, Huber S and Raberger G. 1993. Simultaneous assessment of cardiac output with pulsed Doppler and electromagnetic flowmeters during cardiac stimulation. J. Pharmacol. Toxicol. Methods 30(1):33-38. Lee HS, Kim JB,Kim TH, Wi SM, Kim JY and Choi NG. 2005. Ejection fraction on 3 tesla cardiac MR imaging: evaluation of difference with variable number of slices. J. Kor. Soc. Magnet. Resonance Technol. 15(1):201-208. Lim SJ and Choo KS. 2007. Multi-Detector Computed Tomography for Assessing the Left Ventricular Function, Perfusion and Viability. Korea Circulation J 37(5):191-195. Lofland GK. 2001. The enhancement of hemodynamic performance in Fontan circulation using pain free spontaneous ventilation. Eur. J. Cardio-Thoracic Surg. 20(1):114-119. Matthew A, Tiffanie R, Paul M and Mark A. 2007. Delayedenhancement cardiovascular magnetic resonance identifies fibrous tissue in children after surgery for congenital heart disease. Thoracic Cardiovasc. Surg. J. 133(3):676-681. Manuscript Received: November 9, 2007 Revision Accepted: December 9, 2007