JNN ORIGINAL ARTICLE pissn X eissn 중대뇌동맥에서경두개색조이중도플러초음파와경두개도플러초음파검사의비교연구 박정아정근화김정미이우진고상배이승훈윤

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JNN ORIGINAL ARTICLE pissn 2635-425X eissn 2635-4357 https://doi.org/10.31728/jnn.2017.

1 JNN ORIGINAL ARTICLE pissn X eissn 중대뇌동맥에서경두개색조이중도플러초음파와경두개도플러초음파검사의비교연구 박정아정근화김정미이우진고상배이승훈윤병우 서울대학교의과대학서울대학교병원신경과 Comparative Study of Transcranial Color-Coded Doppler and Transcranial Doppler Sonography in Middle Cerebral Artery Jung-Ah Park, Keun-Hwa Jung, Jeong-Mi Kim, Woo-Jin Lee, Sang-Bae Ko, Seung-Hoon Lee, Byung-Woo Yoon Department of Neurology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea Background: Transcranial color-coded Doppler (TCCD) is a real-time scanning method which evaluates intracranial vessels at high resolution. Whereas transcranial Doppler (TCD) cannot adjust the insonation angle between the ultrasonic wave and blood flow, TCCD can directly view the flow direction so that more accurate flow velocity can be derived. Meanwhile, it is necessary to compare the reference value of the parameters in each test. Methods: Subjects with normal magnetic resonance angiography and TCD were enrolled in neurology clinics. Three test methods were applied for the measurement of middle cerebral arteries (MCAs): 1) Blind-TCD: Blind technique, 2) Image-TCCD: Image-based, and 3) AC-TCCD: angle corrected. Four sample points with depths of mm were evaluated with indices including mean flow velocity (MFV), peak systolic velocity (Vs), end diastolic velocity (Vd), and pulsatility index (PI). Results: Thirty patients with age of 61±17 years were enrolled. MFVs at four depths of MCA were 58±10 (Blind-TCD), 54±10 (Image-TCCD), and 59±12 cm/s (AC-TC- CD). There were no significant differences in the MFVs between Blind-TCD and AC-TCCD (p=0.212). The Vs were 87±17 (Blind-TCD), 90±17 (Image-TCCD) and 99±21 cm/sec (AC-TCCD) with significant differences (p<0.05). The Vs increased in 14% at AC-TCCD over Blind-TCD. PI over age 65 in AC-TCCD was 20% higher than Blind-TCD. Conclusion: Peak systolic velocity can be measured more accurately by AC-TCCD. Image-TCCD and AC-TCCD with small sample volumes are advantageous in that they reflect the change of depth-dependent blood flow more sensitively. Received: October 27, 2017 Revised: May 10, 2018 Accepted: May 10, 2018 Address for correspondence: Keun-Hwa Jung Department of Neurology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 03080, Korea Tel: Fax: jungkh@gmail.com Key Words: Transcranial color-coded Doppler; Transcranial Doppler; Angle correction; Middle cerebral artery Copyright 2018 The Korean Society of Neurosonology This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

2 JNN Jung-Ah Park, et al. Comparative Study of TCCD and TCD in MCA 서론 Doppler 원리를이용한초음파진단법은의학의여러분야 에서적용되고있으며, 특히심장, 말초혈관, 경동맥등의혈류를평가하는중요한수단으로이용되어왔다. 그러나두개골에의하여둘러싸여있는뇌혈관은기존의초음파가투과될수없어진단에한계가있었다. 1982년 Aaslid에의하여처음도입된 Tanscranial Doppler sonography (TCD) 는 2 MHz의저주파 (low frequency, pulsed-waved mode) 를이용함으로써두개내혈관의혈류속도를측정할수있게되었으며, 1 현재는신경과에서뇌혈관질환의진단과연구를위한필수적장비로자리를잡고있다. 그러나두개내혈관의혈류속도는도플러방정식에의한혈관과초음파의입사각도 (0-30 이내 ) 가매우중요한데, 혈관의이미지를보지않고검사하기때문에환자의실제혈관구조와초음파입사각도를맞추는데에있어오차가발생할수있다. TCD의여러선행연구에서중대뇌동맥의주행에는개인차가존재하고, probe의위치나투사각도 (angle of insonation) 를정의할수없으므로혈류속도가불리하게낮게평가되거나측정에실패할우려도있다고하였다. 2,3 서구에서는이미수십년전에경동맥이중초음파장비에 2 MHz probe 장착을하여실시간으로고해상도 (real time scanning, dynamic scanning, B-스캔 ) 영상을이용하여뇌혈관을검사하고있다. 이것이경두개색조이중초음파검사 (transcranial color-coded duplex sonography, TCCD) 이다. TCCD는두개내혈관과뇌실질구조물을고해상으로이미지화시킨검사법이다. B-스캔으로혈관의해부학적정보를제공하므로두개내혈관의정확한동정이가능하다. 4 뇌혈관의혈류정보를다가오는혈관, 멀어지는혈관으로구분하여칼라도플러 (color doppler) 로확인하고, 비정상적측부순환과선천적혈관기형및저형성등도검출이가능하다. 또한, 혈관내에서원하는곳에도플러용적 (sample volume) 을위치시키기가가능하여협착으로인한혈류속도변화를정밀하게측정할수있으며, 혈관과초음파의투사각도를시각적으로정확하게확인할수있다. 5-7 기존의 TCD 검사는간접적으로얻은혈류속도를기준으로평가 (Blind-TCD) 를하였지만, 경두개색조이중초음파검사는직접혈관을보면서혈류속도와혈관구조를관찰 (Image-TC- CD) 하고, 초음파의투사각도를조절할수있어서보다정확한혈류속도를도출 (angle corrected-tccd, AC-TCCD) 할수있다. 현재임상진료에서가장많이사용중인 Blind-TCD와이의단점을보완할수있는 Image-TCCD, AC-TCCD는향후임상에서함께적용될가능성이높은도구로각검사수치의의미는다를수있으므로이에대한표준화가필요하다. 우리나라의현재 TCCD 검사는최근일부대학병원에서시행되기시작하였으나, 아직기준참고수치에대한연구및 TCD 검사결과와의비교연구는시행된바가없다. 따라서, 이번연구는서울 대학교병원의신경과환자를대상으로병력, 임상소견, 뇌자기공명혈관조영술 (magnetic resonance angiography, MRA) 과경두개도플러초음파기준에근거하여정상군을선정하여두개내뇌혈관의혈류속도에대한 TCD와 TCCD의정상참고치와검사에따른수치의변화를제시하고자한다. 대상및방법 본연구는경두개도플러초음파검사 (TCD) 와경두개색조이중초음파 (transcranial color-coded doppler, TCCD) 에서중간대뇌동맥 (middle cerebral artery) 의혈류속도차이를비교하는단면적연구로서울대학교생명윤리심의위원회 (Seoul National University Hospital Biomedical Research Institute) 의승인을받아수행하였다 (H ) 년 12월부터 2017년 5월까지서울대병원신경과외래진료를본환자중전문의에의하여서 TCD 시행이필요하다고판단된환자를대상으로하였다. TCD 검사후측정뇌혈관의혈류속도가정상이고 MRA를통하여뇌혈관의협착및변이가없는환자군을대상으로하였다. 연구측정방법은세가지검사방법으로 1) Blind- TCD: blind technique, 2) Image-TCCD: image-based, 3) AC-TCCD: ultrasound beam과 vessel course가맞지않는경우 angle correction 사용하여검사한다 (Fig. 1). 측정혈관은비교적일관성있게검사가가능한중대뇌동맥 (middle cerebral artery) 으로정하였다. 기존발표된해외논문은중대뇌동맥깊이 (65-48 mm) 1개의 sample을측정하여서평균혈류속도 (mean flow velocity) 를분석하였지만, 6 본연구에서는 Blind-TCD (0-30 ), Image-TCCD (0 ), AC-TCCD (0-50 ) 검사에서중대뇌동맥깊이 (65-48 mm) 4개의 sample을측정하여비교하였다. 모든검사는숙련된검사자한명이수행하였고, 결과의분석은두명의신경과전문의에게보고되어판독되었다. 혈류속도측정변수와인자는평균혈류속도 (mean flow velocity, MFV), 수축기혈류속도 (peak systolic velocity [PSV]; Vs), 이완기혈류속도 (end diastolic velocity [EDV]; Vd), 박동성지수 (pulsatility index, PI) 를포함하였다. 임상적으로중대뇌동맥의 50% 협착의진단기준은 TCD: MFV >100 cm/s 이상이며, TCCD: PSV >155 cm/s 이상, angle correction >50 미만을판독기준으로제시한다. 8 통계적분석은 SPSS (ver. 22.0; IBM, Seoul, Korea) 을이용하여모든매개변수간의차이는평균값과표준편차로기록하였다. Blind-TCD, Image-TCCD, AC-TCCD 방법에서얻은측정치들의평균치비교는 Paired t-test와 ANOVA를사용하였다. 결과의통계적검정은 p-value <0.05를유의하다고판단하였다. 26

Vol. 10 / No. 1 / June 2018 Journal of Neurosonology and Neuroimaging A B C D Fig. 1. Methods of Blind-TCD, Image-TCCD, and AC-TCCD. (A) Doppler spectral signal by Blind-TCD.

3 Vol. 10 / No. 1 / June 2018 Journal of Neurosonology and Neuroimaging A B C D Fig. 1. Methods of Blind-TCD, Image-TCCD, and AC-TCCD. (A) Doppler spectral signal by Blind-TCD. (B) 2D image by Image-TCCD, transtemporal approach, axial midbrain plane, middle cerebral artery (red), anterior cerebral artery (blue). (C, D) AC-TCCD, Upper: transcranial color duplex sonogram of the left middle cerebral artery (MCA). Lower: Doppler ultrasound waveform of the corresponding MCA toward flow pattern. The angle between the Doppler ultrasound beam (dotted line) and the course of the vessel (2 solid lines) is adjusted. Blind-TCD; blind-transcranial Doppler, Image-TCCD; image-based transcranial color-coded Doppler, AC-TCCD; angle corrected transcranial color-coded Doppler. 결과 본연구에포함된환자는총 30명 ( 남자 25명 [83.3%], 여자 5명 [16.7%], 평균연령 61.2±17.0세, 연령범위 세 ) 으로, 임상적특성은 Table 1과같다. 환자들의중대뇌동맥 (middle cerebral artery, MCA) 을 Blind-TCD, Image-TCCD, AC-TCCD에서동일조건으로 4개의깊이 (depth) 를측정하여각각깊이에따른각각의혈류속도차이를비교하였다. 1. AC-TCCD 혈류속도분석본연구는 30명연구대상자개개인별로 2개의뇌반구와 4개의깊이에서혈류속도를측정하여얻은총 240개측정자료를대상으로분석하였다. AC-TCCD 검사에서환자의중대뇌동맥의주행방향이 ultrasound beam과 vessel course가맞지않는경우 angle correction을시행하였다. Angle <30 미만에서는 MFV 55.57±14.52 cm/s이고, angle 에서는 MFV 75.00±15.25 cm/s, angle 에서는 MFV ±15.52 cm/s, angle >50 이상에서 MFV 91.15±21.67 cm/ s였다. Angle값이 30 이상으로증가될수록 MFV가점진적인 증가경향의결과를보여주고있으며, angle correction 방법중에서 angle >50 이상인경우는모두 20개였다. MCA 50% 이상협착 (stenosis) 의판독기준으로 MFV >100 cm/s 적용하였을때 angle >50 이상되는 20개의수치중 6개가 MCA stenosis로 false positive result로 30% 차지하였다 (Fig. 2). 2. Blind-TCD, Image-TCCD, AC-TCCD 방법에따른혈류속도 parameter 분석 Blind-TCD, Image-TCCD, AC-TCCD에서 MCA의혈류속도 MVF, Vs, Vd, PI들의평균과표준편차는 Table 2 와같다. Blind-TCD와 AC-TCCD의 MFV는유의한차이를보이지않았다 (p=0.212). 반면, Vs 경우에는 Blind-TCD, Image-TCCD, AC-TCCD에서유의한차이를보였는데, Blind-TCD < Image-TCCD < AC-TCCD 순으로증가하는경향을보였고, AC-TCCD에서 Blind-TCD보다약 14% 증가하였다 (Fig. 3). Vd에서는 Image-TCCD에서 Blind-TCD, AC-TCCD보다낮은수치를보였다. PI의경우에는 Blind- TCD에비하여 Image-TCCD, AC-TCCD에서유의하게증가하는경향을보였다. 27

Jung-Ah Park, et al. Comparative Study of TCCD and TCD in MCA Table 1. Study population characteristics Variable Value (n=30) Age, years 61.2±17.0 Male sex 25 (83.

7) Use of nitrates 1 (3.3) Values are presented as number of patients (%) or mean±standard deviation. Fig. 2. Corrected angle-dependent mean flow velocity changes measured by TCCD.

4 Jung-Ah Park, et al. Comparative Study of TCCD and TCD in MCA Table 1. Study population characteristics Variable Value (n=30) Age, years 61.2±17.0 Male sex 25 (83.3) Previous stroke history 15 (50) Hypertension 19 (63.3) Diabetes mellitus 4 (13.3) Smoking in past 5 years 5 (16.7) Coronary artery disease 6 (20) Use of calcium channel blocker 8 (26.7) Use of nitrates 1 (3.3) Values are presented as number of patients (%) or mean±standard deviation. Fig. 2. Corrected angle-dependent mean flow velocity changes measured by TCCD. TCCD; transcranial color-coded Doppler, MFV; mean flow velocity. Table 2. Comparisons of the blood flow parameters in middle cerebral artery across three methods Methods (n=60) MFV, cm/s Vs, cm/s Vd, cm/s PI Blind-TCD 58.03± ± ± ±0.146 Image-TCCD 54.08± ± ± ±0.302 AC-TCCD 59.37± ± ± ±0.192 p-value a < <0.001 <0.001 p-value b <0.001 <0.001 < p-value c < <0.001 Values are presented as mean±standard deviation. MFV; mean flow velocity, Vs; peak systolic velocity, Vd; end diastoli c velocity, PI; pulsatility index, Blind-TCD; blind-transcranial Doppler, Image-TCCD; image-based transcranial color-coded Doppler, AC-TCCD; angle corrected-transcranial color-coded Doppler. a p-values comparing Blind-TCD and Image-TCCD. b p-values comparing Image-TCCD and AC-TCCD. c p-values comparing AC-TCCD and Blind-TCD. 3. Blind-TCD, Image-TCCD, AC-TCCD 방법에서 depth 에따른혈류속도분석 Fig. 3. Differences of sonographic parameters between Blind-TCD, Image-TCCD, and AC-TCCD. Blind-TCD; blind-transcranial Doppler, Image-TCCD; image-based transcranial color-coded Doppler, AC-TCCD; angle corrected transcranial color-coded Doppler, MFV; mean flow velocity, Vs; peak systolic velocity, Vd; end diastolic velocity, PI; pulsatility index. Blind-TCD, Image-TCCD, AC-TCCD에서 MCA의 4개의깊이 60 mm, 56 mm, 50 mm, 48 mm에따른혈류속도 MFV, Vs, Vd, PI들의각각평균과표준편차는 Table 3 과같다. MFV와 Vd에서는모든 depth에서 Blind-TCD가 Image-TCCD보다높았고, AC-TCCD가 Image-TCCD보다높았다. 즉, Image-TCCD의경우모든 depth에서가장낮은것으로나타났다. Vs의경우에는모든 depth에서 Image-TCCD와 AC-TCCD의유의수준은 p<0.05로유의한관계를나타내었고, depth 56 mm과 50 mm에서는 Blind- TCD < Image-TCCD < AC-TCCD 순으로높아지는것으로나타났다. 특히, depth 56 mm에서 AC-TCCD가 Blind- TCD에비하여 20% 증가되어있다 (Fig. 4). PI의경우에는모 28

5 Vol. 10 / No. 1 / June 2018 Journal of Neurosonology and Neuroimaging 든 depth에서 Blind-TCD와 Image-TCCD의유의수준은 p<0.01이고, Blind-TCD와 AC-TCCD의유의수준은 p<0.01 로유의한관계를나타내었다. Image-TCCD, AC-TCCD의모든 depth에서 Blind-TCD보다높은수치값을나타내었다. 그러나 Image-TCCD와 AC-TCCD 간에는유의한차이가관찰되지않았다. 4. Blind-TCD, Image-TCCD, AC-TCCD 방법에서 age 에따른혈류속도 parameter 분석 Blind-TCD, Image-TCCD, AC-TCCD에서환자의 age 에따른 MCA의 MFV와 PI의변화를분석한결과는 Table 4 에서기술한다. Age 65세이상군에서 65세미만군에비하여 Blind-TCD, Image-TCCD, AC-TCCD에서모두통계적으로유의하게 MFV가낮았고 PI가높았다. Age를중간값인 65세 Table 3. Comparisons of the blood flow parameters in several depths of middle cerebral artery across three methods Depth 60 mm Depth 56 mm Depth 50 mm Depth 48 mm MFV, cm/s Blind-TCD 59.75± ± ± ±10.66 Image-TCCD 56.25± ± ± ±10.66 AC-TCCD 58.75± ± ± ±15.48 p-value a <0.001 p-value b <0.001 < p-value c Vs, cm/s Blind-TCD 90.16± ± ± ±18.43 Image-TCCD 98.12± ± ± ±22.36 AC-TCCD 98.12± ± ± ±25.70 p-value a < p-value b <0.001 < p-value c <0.001 < Vd, cm/s Blind-TCD 41.05± ± ± ±08.02 Image-TCCD 37.34± ± ± ±09.89 AC-TCCD 38.98± ± ± ±12.03 p-value a < <0.001 p-value b < p-value c PI Blind-TCD 0.827± ± ± ±0.166 Image-TCCD 0.997± ± ± ±0.210 AC-TCCD 0.998± ± ± ±0.208 p-value a <0.001 <0.001 <0.001 <0.001 p-value b p-value c <0.001 <0.001 <0.001 <0.001 Values are presented as mean±standard deviation. MFV; mean flow velocity, Blind-TCD; blind-transcranial Doppler, Image-TCCD; image-based transcranial color-coded Doppler, AC-TC- CD; angle corrected transcranial color-coded Doppler, Vs; peak systolic velocity, Vd; end diastolic velocity, PI; pulsatility index. a p-values comparing Blind-TCD and Image-TCCD. b p-values comparing Image-TCCD and AC-TCCD. c p-values comparing AC-TCCD and Blind-TCD. 29

Jung-Ah Park, et al. Comparative Study of TCCD and TCD in MCA Fig. 4. Differences of sonographic parameters between Blind-TCD, Image-TCCD, and AC-TCCD according to sampling depth.

6 Jung-Ah Park, et al. Comparative Study of TCCD and TCD in MCA Fig. 4. Differences of sonographic parameters between Blind-TCD, Image-TCCD, and AC-TCCD according to sampling depth. Blind-TCD; blind-transcranial Doppler, Image-TCCD; image-based transcranial color-coded Doppler, AC-TCCD; angle corrected transcranial color-coded Doppler, MFV; mean flow velocity, Vs; peak systolic velocity, Vd; end diastolic velocity, PI; pulsatility index. Table 4. Differences of the blood flow parameters in middle cerebral artery according to age MFV PI Blind-TCD Image-TCCD AC-TCCD Blind-TCD Image-TCCD AC-TCCD Age, years <65 (n=30) 62.17± ± ± ± ± ± (n=30) 53.88± ± ± ± ± ±0.207 p-value <0.001 Values are presented as mean±standard deviation. MFV; mean flow velocity, PI; pulsatility index, Blind-TCD; blind-transcranial Doppler, Image-TCCD; image-based transcranial color-coded Doppler, AC-TCCD; angle corrected transcranial color-coded Doppler. 기준으로하여 65세이상 (n=30) 과 65세미만 (n=30) 에서각검사방법에따른측정결과를비교하였을때 PI의증가는 Blind-TCD에비하여 Image-TCCD와 AC-TCCD에서좀더뚜렷하였다 (Fig. 5). 고찰 건강인, 혈관연축 (vasospasm), 혈관협착환자에서 TCCD 의연관성은잘알려져왔고, angle correction에따라서혈 30

Vol. 10 / No. 1 / June 2018 Journal of Neurosonology and Neuroimaging Fig. 5. Differences of sonographic parameters between Blind-TCD, Image-TCCD, and AC-TCCD according to age.

7 Vol. 10 / No. 1 / June 2018 Journal of Neurosonology and Neuroimaging Fig. 5. Differences of sonographic parameters between Blind-TCD, Image-TCCD, and AC-TCCD according to age. Blind-TCD; blind-transcranial Doppler, Image-TCCD; image-based transcranial color-coded Doppler, AC-TCCD; angle corrected transcranial color-coded Doppler, MFV; mean flow velocity, PI; pulsatility index. 류가증가되는경향이보고된바있다. 8 대다수의선행연구들 에서 angle correction은 TCCD의하나의장점이지만, angle correction의사용의범위가매우제한적이다. 이는선천적혈관변이 (anatomic variation) 또는개인에따라혈관의굽어짐 (tortuosity) 또는동일인에서양쪽차이 (interhemispherically) 등으로그범위가매우가변적일수있다. 본연구에서도개인에따라넓은가변성 (angle 0-70 ) 이있음을확인할수있었다. Hoksbergen 등 9 은 angle correction >50 이상의큰각도에서는높은혈류속도를도출하여오류의원인이될수있기때문에, 굽어짐등에구불구불한혈관에서는 non angle correction을권장하였다. 이번연구에서도 angle correction >50 이상의큰각도에서는 MCA 협착에대한 false positive 도출할가능성이높음을알수있었다. Angle이 >50 연구대상자를분석하여보면대부분고령군에서 M1 혈관의굽어짐이심하고, M2에서는혈관굽어짐이더심하였다. 추후고령군의혈관영상검사와자세한비교연구가필요하다고생각된다. MCA에서 Blind-TCD, Image-TCCD, AC-TCCD의평균혈류속도 parameter 분석에서는 Vs가다른변수들에비하여높은평균값을보였다. Schöning 등의보고에의하면 MCA의 MFV는 Blind-TCD 61±13, Image-TCCD 58±12, AC-TCCD 67±12 (cm/s) 였다. Vs의 Blind-TCD 92±16, Image-TCCD 92±18, AC-TCCD 107±18 (cm/s) 였다. 즉, AC-TCCD 방법에의한 MFV, Vs가약 10-15% Blind-TCD 보다높았다. 10,11 본연구에서는 MCA의 MFV는 Blind-TCD 58±10, Image-TCCD 54±10, AC-TCCD 59±12 (cm/s) 로유사하였다. 그러나 Vs는 Blind-TCD 87±17, Image-TC- CD 90±17, AC-TCCD 99±21 (cm/s) 로 Blind-TCD와 Image-TCCD에비하여 AC-TCCD에서 Vs가높았다. 본연구에서도 AC-TCCD에서 Blind-TCD보다 Vs가 14% 증가를보였는데, 이것은 angle correction으로인한 peak systolic velocity의정확한측정이가능함 5 을보여주는것이라고사료된다. 그러나 MFV에서 Blind-TCD와 AC-TCCD의유의수준은 p=0.212로유의하지못하였다 (Table 1). 이는 TCCD 검사에서 Vd의저하및고령군에서혈관탄성도의변화가영향을주었을가능성이있다. 12 MCA에서 Blind-TCD, Image-TCCD, AC-TCCD의 4개의 depth에따른혈류속도를분석한결과, Blind-TCD와 AC-TCCD에서 depth에따른 MFV와 Vd의측정값은대체로비슷하나, Image-TCCD에서는 MFV와 Vd값이다른두측정방법에비하여상대적으로낮게관찰되었다. 이는소아겸상적혈구병환자의두개내혈관에대하여서각방법에따른 MFV 를비교한선행연구에서도관찰되는바이다. 13 해당연구에서 MFV의값은 Image-TCCD를통하여측정하였을때, Blind- TCD에의한측정에비하여평균 20% 낮게측정되었으며, 이러한차이는내경동맥 (internal carotid artery, ICA), 앞대뇌동맥 (anteriro cerebral artery, ACA), 후대뇌동맥 (posterior cerebral artery, PCA) 등 insonation angle이좋지않은혈관에서두드러졌고, Image-TCCD에 AC-TCCD을시행함으로써상쇄되었다. 해당연구에서 MFV를측정할때각검사방법별로 insonation depth가최대 20 mm까지차이가났지만본연구에서는 insonation depth를통제한점, 해당연구에서는다양한혈관에서 MFV를분석하였지만, 본연구에서는 MCA만을분석하였다는점에의하여해당연구의결과와본연구에서관찰된바를직접비교하기는무리가있다. 하지만해당연구와본연구에서공통적으로시사하는바는, 특히 insonation angle이좋지않은혈관에서다양한측정오류가발생할수있고, 이경우 angle correction에의하여측정의정확도가향상될수있다는점이다. 13 한편, Vs의경우 Blind-TCD < Image-TCCD < AC-TC- CD 순으로측정값이증가하는것으로나타났으며, depth별로 56 mm과 50 mm에서좀더차이가뚜렷하였다. Depth 56 mm에서의 Vs는통계적인분석에서도 Blind-TCD, Image-TCCD, AC-TCCD의세가지측정방법모두에서유의한결과를보였다. 특히, depth 56 mm에서 AC-TCCD 가 Blind-TCD에비하여 20% 증가되었는데, 이것은 sample volume의 focality와연관성이있다고사료된다. 이전보고된 depth에따른연구분석이없어서본연구와비교를할수없었다. 그러나수축기 (Vs) 지표의증가가 Image-TCCD와 AC-TCCD가 Blind-TCD보다더높은이유는 Image-TCCD 는 MCA 측정시샘플볼륨 3 mm 적용하여서검사하기때문이며, depth 간격을작은 segment로나눠서검사가가능하여 Blind-TCD처럼앞뒤속도값에영향이없음을확인하였다. 또한 Image-TCCD의속도는혈관을 B-스캔이미지와색도플러 (color doppler) 에서유동적인혈류흐름을관찰하고 ( 난혈류관찰가능 ), 샘플용적내도플러혈류속도를측정하여이중점검 (double check) 이가능하여 blind TCD보다정밀하게 31

8 Jung-Ah Park, et al. Comparative Study of TCCD and TCD in MCA 측정할수있다. 즉, Image-TCCD, AC-TCCD는높은것은높게낮은것은낮게측정가능하여국소영역측정이가능하다. 이것은 Vs를높게잡을수있는민감도와연결지을수있다. 선행연구에따르면 PI는수축기, 이완기, 평균혈류속도사이의관계를나타내며혈관벽의탄성 (elasticity) 과관련이있다. 즉, PI 지표는협착, 혹은뇌압항진을의미하며연령이높아짐에따라증가하는경향이있으며 age가 60세이상에서 MFV는감소하고 PI는증가된다 14,15 고보고가있다. 본연구에서도 Blind-TCD < Image-TCCD < AC-TCCD에서 age 65세이상에서 65세미만에비하여 PI는증가하였고, MFV 는감소하는것으로관찰되었다. 특히, PI의경우 65세이상 AC-TCCD에서 Blind-TCD보다 20% 높게측정되었다. 이와같은결과도 angle correction을사용하여혈관의빠른유속흐름을반영한선행연구의결과를뒷받침하는것으로사료된다. 10 또한, 고령의나이에서 PI의증가는 Image-TCCD, AC-TCCD에서특히높음을보여주었는데, 이는 Vs 증가와 sample volume의 focality와연관성이있다고사료된다. 향후고령군대상으로 PI 비교를위한후속연구연구가필요할것으로생각된다. 본연구에서는몇가지제한점을가지고있다. 첫째, 30명의적은연구대상자수의한계로혈관위험인자및기타혈관질환들과의관련성을알아보는데는어려움이있었다. 둘째, 이번연구는 1명의검사자에의하여수행된결과로서 Blind- TCD, Image-TCCD, AC-TCCD에측정에있어다른검사자간에재현성 (reproducibility) 검증을하여측정치의정량적인관계를알아보는데는무리가있었다. 셋째, angle correction 으로 MFV가많이증가된환자에대하여서는 MRI/MRA와의비교도가능할것으로판단하나 sample 수가작고 image-tcd와 MRA 시행간격이다양한것이제한적이었다. 넷째, 검사자의기술적 (technical) 측면으로 angle correction은 MCA의주행방향에맞추어정확한속도반영함을위함인데, 혈관이구불구불한경우트랜스듀서를조작하여혈관동정하는것에매우어려움이있었다. 또한대뇌혈관의직경이 2-4 mm로작기때문에색도플러만보이고혈관벽은잘가시화되지않는다는점도제한점이었다. 따라서검사방법의신뢰성있는 angle with correction 방법의표준화는매우어려움이따를것으로판단된다. 또한 ACA, PCA 등혈관주행에굴곡이있는다른 intracranial artery에 angle correction 적용을획일적으로표준화할수없다는것또한제한점이었다. 이것은병원간, 검사자간동일검사를추적관찰시에이전검사의 angle 재현성에문제있다. 추후에이러한문제점을보안하여더욱객관화한다면뇌혈관질환자들의혈류역학적평가에추적검사및치료효과를판단하는데많은도움을줄수있을것으로기대된다. REFERENCES 1. Aaslid R, Markwalder TM, Nornes H. Noninvasive transcranial Doppler ultrasound recording of flow velocity in basal cerebral arteries. J Neurosurg. 1982;57: Aaslid R. The Doppler principle applied to measurement of blood flow velocity in cerebral arteries. In: Aaslid R. Transcranial doppler sonography. Vienna: Springer. 1986; Alexandrov AV, Sloan MA, Wong LK, Douville C, Razumovsky AY, Koroshetz WJ, et al. Practice standards for transcranial Doppler ultrasound: part I--test performance. J Neuroimaging. 2007;17: Martin PJ, Evans DH, Naylor AR. Measurement of blood flow velocity in the basal cerebral circulation: advantages of transcranial color-coded sonography over conventional transcranial Doppler. J Clin Ultrasound. 1995;23: Krejza J, Mariak Z, Walecki J, Szydlik P, Lewko J, Ustymowicz A. Transcranial color Doppler sonography of basal cerebral arteries in 182 healthy subjects: age and sex variability and normal reference values for blood flow parameters. AJR Am J Roentgenol. 1999;172: Bogdahn U, Becker G, Winkler J, Greiner K, Perez J, Meurers B. Transcranial color-coded real-time sonography in adults. Stroke. 1990;21: Brouwers PJ, Vriens EM, Musbach M, Wieneke GH, van Huffelen AC. Transcranial pulsed Doppler measurements of blood flow velocity in the middle cerebral artery: reference values at rest and during hyperventilation in healthy children and adolescents in relation to age and sex. Ultrasound Med Biol. 1990;16: Baumgartner RW, Mattle HP, Schroth G. Assessment of 50% and <50% intracranial stenoses by transcranial color-coded duplex sonography. Stroke. 1999;30: Hoksbergen AW, Legemate DA, Ubbink DT, Jacobs MJ. Success rate of transcranial color-coded duplex ultrasonography in visualizing the basal cerebral arteries in vascular patients over 60 years of age. Stroke. 1999;30: Krejza J, Mariak Z, Babikian VL. Importance of angle correction in the measurement of blood flow velocity with transcranial Doppler sonography. AJNR Am J Neuroradiol. 2001;22: Schöning M, Buchholz R, Walter J. Comparative study of transcranial color duplex sonography and transcranial Doppler sonography in adults. J Neurosurg. 1993;78: Ackerstaff RG, Keunen RW, van Pelt W, Montauban van Swijndregt AD, Stijnen T. Influence of biological factors on 32

9 Vol. 10 / No. 1 / June 2018 Journal of Neurosonology and Neuroimaging changes in mean cerebral blood flow velocity in normal ageing: a transcranial Doppler study. Neurol Res. 1990;12: Krejza J, Rudzinski W, Pawlak MA, Tomaszewski M, Ichord R, Kwiatkowski J, et al. Angle-corrected imaging transcranial Doppler sonography versus imaging and nonimaging transcranial doppler sonography in children with sickle cell disease. AJNR Am J Neuroradiol. 2007;28: Grolimund P, Seiler RW. Age dependence of the flow velocity in the basal cerebral arteries--a transcranial Doppler ultrasound study. Ultrasound Med Biol. 1988;14: de Riva N, Budohoski KP, Smielewski P, Kasprowicz M, Zweifel C, Steiner LA, et al. Transcranial Doppler pulsatility index: what it is and what it isn t. Neurocrit Care. 2012;17:

서론 34 2

서론 34 2 34 2 Journal of the Korean Society of Health Information and Health Statistics Volume 34, Number 2, 2009, pp. 165 176 165 진은희 A Study on Health related Action Rates of Dietary Guidelines and Pattern of