Development of a Non-invasive Ultrasonic Measurement System for tissue elasticity

Transcription

1 J Biomed Eng Res : 이균정 1 최우혁 1 유재원 1 서종범 1 최서형 2 신태민 1 1 Development of a Non-invasive Ultrasonic Measurement System for tissue elasticity G J Lee 1 W H choi 1 J W Yu 1 J B Seo 1 S H Choi 2 T M Shin 1 1 Department of Biomedical Engineering Yonsei University 2 Hana traditional Oriental medicine hospital (Received January Accepted December 2 29) Diseases caused by indurate tissues of the internal organs are liver cirrhosis and abdominal sclerosis The cause of chronic gastro-intestinal disease is a digestive system disorder and a defecation disorder They impede peristaltic movement and digestive system with the symptom that indurate tissues The purpose of the present study was to determine the disease grade quantitatively by measuring an indurated standard of tissues and organs For the measurement of elasticity we designed the system that measure the displacement of the substance and approved pressure using ultrasound transducer For verification of developed system we compared elasticity as results of experiment between the developed system and public elasticity measurement machine at individual plastic phantoms made by plastic hardener and softener Elasticity of the plastic phantoms is averagely 7MPa lower measured by developed system than Micro-indenter and less than 1% errors Comparing with economical value and accuracy between developed system and Micro-indenter the system is significant of measurement for tissue elasticity Thus it is possible to measure a elasticity at human tissue and organ A chronic gastro-disease as well as grade could be decided objective validity using this system indurate tissues elasticity ultrasound echo pressure measurement Ⅰ 서론 Ki Tae Suk[1] Takaki[2] Min Leabu[3] (interstitial cells of Cajal) Corresponding Author : 신태민 (22-842) 강원도원주시흥업면매지리첨단의료기기테크노타워 22 호 Tel : / Fax : tmshin@yonseiackr 2 (cross-correlation) Ophir[4] Chen[5] TOF(time of flight) Vol 3 December

2 Development of a Non-invasive Ultrasonic Measurement System for tissue elasticity 1-3 (speckle) (speckle tracking) O'Donnell[6] Lubinski[7] 15 r2(n) r1(n) 1 Amplitude 5 (plastic phantom) Ⅱ 이론적배경 Sample number 그림 1 압력인가전 (r1(n)) 과후초음파신호 (r2(n)) 를나타냄 Fig 1 Appear befor and after the approved pressure echo-signal Zhang[8] (4) (4) ( (1)) phase sensitive cross-correlation [8] (υ) 5 Indentation - (4) k Wellman[9] (5) K (5) K [8] (2) 1 (2) τ T Lubinski [7] FHWM(full half width maximum) (autocorrelation) (2) (Maximum Cross Correlation Coefficient) (3) (τ) [7] (1) (1) (2) 47 J Biomed Eng Res

3 G J Lee W H choi J W Yu J B Seo S H Choi T M Shin (3) (4) PC 2 (( ) ) 5MHz 75mm (Load Cell Model34 Honeywell) (N) 5N 45N (PR573 Panametric-NDT USA) 59dB DAQ(PCI5122 NI:national instrument) LabVIEW92 A 시스템구성 Ⅲ 시스템설계 ( 2) (5) B 신호처리부 5MHz 1~4cm 2 LabVIEW (demodulation) (base band signal) (time gain compensation) n n-1 3 n n-1 peak hoping window) [6] (hanning Pre-AMP P&R 압력센서 Ⅳ 시스템검증을위한팬텀실험 초음파변환기 플라스틱팬텀 DAQ 5:5 PC 그림 2 초음파탄성도측정시스템의구성도 Fig 2 The blocks of the ultrasound elasticity measurement system [1] Micro-indenter Vol 3 December

4 Development of a Non-invasive Ultrasonic Measurement System for tissue elasticity A 플라스틱팬텀의제작 3 1:9 2:8 3:7 4:6 5:5 (Scatterer) Amberlite 5% 5mm 5mm 7mm 5% SNR [1] B 실험방법 그림 4 Micro Indenter 를이용한팬텀의탄성도측정 Fig 4 Elasticity measurement of the phantom with Micro Indenter Micro-indenter Indentation - 1) Micro Indenter Micro-Indenter(model 5848 Instron) 4 Micro Indenter (Bluehill) ~2 N ~2 N 1 1 2) ~2N 5 ~2N N 1 1 (a) (b) (c) (d) (e) 그림 3 제작된플라스틱팬텀 (1:9(a) 2:8(b) 3:7(c) 4:6(d) 5:5(e)) Fig 3 Designed plastic phantoms : plastic softener ratio 그림 5 설계된초음파탄성도측정시스템으로팬텀탄성도측정 Fig 5 Measurement of the elasticity on phantom with designed ultrasound elasticity measurement system 472 J Biomed Eng Res

5 G J Lee W H choi J W Yu J B Seo S H Choi T M Shin Stress(Pa) % (a) 2% (b) 3% (c) 4% (d) Displacement(mm) % (e) Strain Depth(cm) 그림 6 Micro Indenter 의응력 - 변형률선도 Fig 6 Stress-Strain Diagram of the Micro Indenter 그림 8 연화제비가 1:9 인팬텀에서깊이에따른평균변위와표준편차 Fig 8 Averaged displacement and standard deviation with depth of the phantom as softener ratio 1% Ⅳ 결과 Micro-Indenter Micro-Indenter - 1: cm 8 1:9 5cm 1 1 (4) (stress) - 9 Micro-Indenter Displacement(cm) Stress(Pa) % (a) 2% (b) 3% (c) 4% (d) -12 5% (e) Pressure(N) Strain 그림 7 인가압력값에대한평균변위 Fig 7 Average displacement with the input pressure 그림 9 설계된시스템의응력 - 변형률선도 Fig 9 Stress-Strain Diagram of the designed system Vol 3 December

6 Development of a Non-invasive Ultrasonic Measurement System for tissue elasticity 표 1 각팬텀에서깊이에따른평균변위 (μm) Table 1 Average displacement with depth of each phantom 1cm 15cm 2cm 25cm 3cm 35cm 4cm (a) (b) (c) (d) (e) Micro- Indenter 5% 16% (a) 7MPa [ 6] Ⅴ 고찰 Indentation 5 Wallman[9] K Micro Indenter 6 (a) (b) (c) (d) (e) 5% 9 1 (c) 4cm Micro Indenter 1 Young's modulus(pa) a b c d e Samples Indenter Ultrasound 그림 1 각팬텀에서 Indenter 와초음파탄성도측정시스템를이용한탄성도측정값 (Pa) Fig 1 Elasticity measurement value used Micro Indenter and designed system at each phantoms Ⅵ 결론 Pulser&Receiver Micro Indenter 7MPa 474 J Biomed Eng Res

7 G J Lee W H choi J W Yu J B Seo S H Choi T M Shin Micro Indenter LabView 참고문헌 [1] Ki Tae Suk Dae Wook Lim Moon Young Kim Dong Hun Park Kyu Hong Kim Jung Min Kim Jae Woo Kim Hyun Soo Kim Sang Ok Kwon Soon Koo Baik Sung Jin Park Thickening of the Gastric Wall on Transabdominal Sonography: A Sign of Gastric Cancer Journal of Clinical Ultrasound Vol 36 No 8 pp [2] Takaki M Gut pacemaker cells: The interstitial cells of Cajal (ICC) J Smooth Muscle Res J Smooth Muscle ResVol 39 No 5 pp [3] K W Min and M Leabu interstitial cells of cajal(icc) and gastrointestinal stromal tumor(gist): facts speculations and myths J Cell Mol Medvol 1pp [4] Ophir J CCspedcs I Ponnekanti H Yazdi Y et al Elastography: a quantitative method for imaging the elasticity of biological tissues Ultrasonic Imaging Vol 14 pp I [5] Chen EJ Novakofski J Jenkins WK O Brien WD Jr Young s modulus measurement of soft tissues with application to elasticity imaging IEEE trans Ultrasonics Ferroelectrics and Frequency control 1996;43(1): [6] M O'Donnell A RSkovoroda B M Shapo and S Y Emelianov Internal displacement and strain imaging using ultrasonic speckle tracking IEEE Trans Ultrason Ferroelect Freq Contr vol 41 pp May 1994 [7] Mark A Lubinski Speckle Tracking Methods for Ultrasonic Elasticity Imaging Using Short-Time Correlation IEEE Trans Ultrason Ferroelect Freq Contr vol 46 NO 1 January 1999 [8] Zhang M Zhang YP and Mak AFT Estimating the effective Young's modulus of soft tissues form indentation tests-nonlinear finite element analysis of effects of friction and large deformation Med Eng Phys Vol 19 No6 pp [9] P Wellman R Howe E Dalton and K A Kern Breast tissue stiffness in compression is correlated to histological diagnosis Tech Rep Harvard BioRobotics Laboratory Harvard University Cambridge Mass USA 1999 [1] Journal of Biomedical Engineering Research 29 4 pp Vol 3 December