目前醫院醫療資訊電子化的過程中，醫療影像儲傳系統（PACS）的建立可以說是非常重要而且是關鍵性的一環。但因為傳統診斷影像檔案的儲存、擷取需要相當大的空間及人力成本；尤其目前醫院使用的診斷儀器大多仍是只提供類比輸出，必須經由類比/數位轉換才能在PACS上傳輸。超音波是目前臨床診斷儀器中僅次於x光儀為第二普普遍的診斷儀器，除了及少數新型的超音波儀器直接提供影像的數位檔案外，大都仍是類比影像輸出，因此DICOM Gateway系統提供了重要的轉換介面。

　　目前國人罹患心臟血管疾病有逐年增加的趨勢，而且已躍為國人十大死亡病因之第二位。頸動脈超音波是目前臨床診斷血管疾病的利器之一，B-mode頸動脈超音波動態影像是提供臨床醫師診斷參考依據。頸動脈超音波可以提供橫切面影像，從這些影像中我們利用影像處理的技術可以獲得血管面積，若能配合即時血壓量測便可以求得血管彈性。血管彈性參數已有很多研究報告指出，它是評估動脈硬化很好的方法之一。

　　本研究的目的乃經由DICOM Gateway介面系統，從傳統超音波儀類比之輸出取得影像後轉換為數位檔，一方面可以作為PACS系統的介面，同時開發影像處理系統程式進行血管參數的量測，可提供臨床醫師對心血管疾病診斷參考。系統分析結果顯示：
（1） 經由7位使用者對系統進行面積計算測試，其面積平均值為76.96mm²，標準差為1.23mm²。
（2）邊界搜尋線起始點選在血管腔中心點附近可獲得較佳搜尋結果。
（3）20張影像經由系統面積運算結果與手繪面積結果分析，其平均面積誤差為8.17％。
（4）系統最佳邊界搜尋角度為2度角。
（5）分別將血管內膜-中膜厚度大於和小於0.985mm的影像資料進行彈性分析，發現兩者有明顯差異性。

　The buildup of the PACS is an important issue on hospital for electronic medical record. The storage and acquisition of conventional diagnostic images needs more space and cost. Most of the diagnostic modality currently used in hospital only provide the analog outputs, which need the Analog/Digital conversion to interface with PACS system. The ultrasound is the second popular diagnostic to X-Ray in clinics. Most of ultrasound equipments provide the B-mode images which only can be accessed from the analog devices.

　Cardiac vascular disease has become the second mortality in Taiwan. Carotid artery ultrasound provides the dynamic B-mode images of common carotid artery (CCA), which is a good index for clinician to diagnose arteriosclerosis. Besides the cross-section images, we can use image processing to get vascular area. If the real-time blood pressure could be recorded integrally then the arterial compliance can be estimated. It is an useful tool for arteriosclerosis in clinic.

　The purpose of this study is to acquire the images from conventional ultrasound instruments through the DICOM Gateway system, then, the digital images converted from acquired images will be communicated with PACS system. In addition, the quantitative vascular parameters analysis software will also be developed in this system. Consequently, the developed system will be helpful to diagnose the vascular diseases in clinic. The results show:
（1） The system tested by 7 users, vascular area measurement mean value equal to 76.96mm2, S.D equal to 1.23mm²
（2） Origin of radial edge-detection line varying nearby center point of vessel gets optimal results.
（3） Average error between manual and automatic is 8.178%.
（4） The optimum radial edge-detection angle equal to 2°.
（5） The patients with IMT<0.985mm and IMT>0.985mm has significant difference in compliance.

參考文獻

[1] 行政院衛生署2003年衛生統計指標
[2] D. H. O’Leary, J. F. Polak, and S. K. Wolfson Jr., “Use of sonography to evaluate carotid atherosclerosis in elderly the cardiovascular health study,” Stroke, vol. 22, pp. 1155-1163, 1997
[3] E. Grobbee and M. L. Bots, “Carotid artery intima-media thickness as indicator of generalized atherosclerosis,” Journal of internal Medicine vol. 236, pp. 341-360, 1994.
[4] M. F. O’Rourke and G. Mancia, “Arterial stiffness,” Journal of Hypertension, vol. 17, no 1, pp.1-4, 1999.
[5] E. Shalman, and S. Einav, “A method for estimating the physiological significance of each of serial vascular lesions,” Proceeding of the 23rd annual EMBS International Conference, pp. 25-28, 2001.
[6] H. Schmidt, R. Schmidt, A. Gradert and K. Niederkorn, “Paraoxonase PON1 polymorphism Leu-Met54 is associated with
carotid atherosclerosis: results of the Austrian stroke prevention
Study,” Stroke, vol. 29, pp. 2043-2048, 1998.
[7] 阮耀鋒，『利用超音波影像評估血管的彈性特性』，國立成功大學醫學工程研究所，碩士論文，2001.6
[8] M. Mischi, A. Kaller, and H. Korsetn, “Cardiac image segmentation for contrast agent videodensitometry,” IEEE Transaction on Biomedical Engineering, vol. 52, no.2, 2005.
[9] O. Frank, O. Die “Grundform desarteriellen pulse erste Abhandlung: mathematische Analyse,” Z. Biol. vol. 37, pp, 483-526, 1899.
[10] T. Imura, K. Yamamoto, K. Kanamori, T. Mikami and H. Yasuda,
“Non-invasive ultrasonic measurement of the elastic properties of
the human abdominal aorta,” Cardiovasc. Res. vol. 20, pp. 208-
214, 1986.
[11] F. Hansen, P. Mangell, B. Sonesson and T. Lanne, “Diameter and
compliance in the human common carotid artery-variations with
age and sex,” Ultrasound Med. Biol., vol. 21, no. 1, pp. 1-9, 1995.
[12] R. W. Stadler, W. C. Karl, and R. S. Lees, “The application of echo- tracking method to endothelium-dependent vasoreactivity and arterial compliance measurements,” Ultrasound in Med. Biol., vol. 22, no. 1, pp. 35-42, 1996.
[13] G. Woods, Digital Image Processing, 2nd, Prentice Hall, United State of America, 2002.
[14] H. Maeda, N. Handa, M. Matsumoto, Hi. Hougaku, S. Ogawa, N. Oku, T. Itoh, H. Moriwaki, S. Yoneda, K. Kimura and T. Kamada, “Carotid lesions detected by B-mode ultrasonography in takayasu’s arteritis : Macaroni sign as an indicator of the disease,’’ ultrasound in Med. & Biol., vol. 17, no. 7, pp. 695-701, 1991.
[15] H. Marieb and R. Mallatt, Human Anatomy, Benjamin, New York, pp. 480-485, 1997.
[16] G. Vander, Human Physiology, McGRAW-HILL, United States of
America, pp. 430-431, 1994.
[17] D. M. Herrington, T. Johnson and P. Santago, “Semi-automated
boundary detection for intravascular ultrasound,” Computers in
Cardiology, pp. 103-106, 1992.
[18] W. A. Riley, R. W. Barnes, W. B. Applegate and R. Dempsey, “Reproducibility of noninvasive ultrasonic measurement of carotid atherosclerosis,” Stroke, vol. 23, pp. 1062-1068, 1992.
[19] DICOM V3.0
[20] http://www.gehealthcare.com
[21] www.vghtpe.gov.tw/~rad/staff/rsna98.htm
[22] 台北榮總放射線部，孫英洲，參加「北美放射醫學年會」暨參觀「哥倫比亞大學醫療資訊研究所」等地－出國心得報告
[23] H. Safar, J.-J. Mourad, M. Safar and J. Blacher，“Aortic Pulse Wave Velocity, an Independent Marker of Cardiovascular Risk, ” ARCHIVES DES MALADIES DU COEUR ET DES VAISSEAUX, vol. 95, no. 11, 2002.
[24] 潘慧本，『超音波的無片環境---高雄榮總的經驗』，http://www.sumroc.org.tw/book/e007-3.htm
[25] 楊宗龍，『從DICOM TAG看數位醫學影像』，http://61.62.116.208/webhd/adams/2004.html
[26] H. Tomiyama, A. Yamashina, T. Arai, K. Hirose, Y. Koji, T. Chikamori, S. Hori, Y. Yamamoto, N. Doba, and S. Hinohara, ”Influence of age and gender on results of noninvasive brachial-ankle pulse wave measurement—a survey of 12517 subjects,” Atherosclerosis, vol.166, pp.303–309,2003.
[27] K. R. Waters, S. L. Bridal, C. C. Bacrie, C. Levrier, P. Fornes, and P. Laugier, “Parametric analysis of carotid plaque using a clinical ultrasound imaging system,” Ultrasound in Med. Biol., vol. 29, no. 11, pp. 1521-1530, 2003.
[28] G. Pok, J. C. Liu, A. S. Nair, “Selective removal of impulse noise based on homogeneity level information,” IEEE Transactions on Image Processing, vol. 12, no. 1, January 2003.
[29] W. Yao, J. Tian, B. Zhao, N. Chen, and G. Qian, “Star algorithm: detecting the ultrasound endocardial boundary automatically,”Ultrasound in Med. Biol., vol. 30, no. 7, pp. 943-951, 2004.
[30] T. Nagakura, K. Masuda. Y. Ooe, S. Kosuge, and Y. Hase, “The non-invasive functional tissue characterization for arteriosclerosis by artery wall motion analysis wiht time series hight-speed echo images and continuous Spygmo-manometer,” Proceedings of the 23rd Annual EMBS International Conference, pp. 25-28, 2001.
[31] R. H. Selzer, W. J. Mack, P. L. Lee, H. Kwong-Fu, H. N. Hodis, “Improved common carotid elasticity and intima-media thickness measurements from computer analysis of sequential ultrasound frames,” Atherosclerosis, vol. 154, pp. 185-193, 2001.
[32] T. Kawasaki, S. Sasayama, S. Yagi, T. Asakawa and T. Hirai, “Non- invasive assessment of the age related changes in stiffness of major branches of the human arteries,” Cardiovascular Research, vol. 21, pp. 678-687, 1987.
[33] S. Y. Chuang, C. H. Chen, C. M. Cheng, P. Chou, “Combined use of brachial-ankle pulse wave velocity and ankle-brachial index for fast assessment of arteriosclerosis and atherosclerosis in a community,” International Journal of Cardiology, vol. 98, pp.99– 105, 2005.