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Volumn 38, Issue 5, 2009, Pages 586-596

Dynamics of the Aorta Before and After Endovascular Aneurysm Repair: A Systematic Review

Author keywords

Abdominal aortic aneurysms; Dynamics; Stent graft; Thoracic aortic aneurysms

Indexed keywords

ABDOMINAL AORTA; ABDOMINAL AORTA ANEURYSM; ANEURYSM SURGERY; AORTA ANEURYSM; AORTA GRAFT; ARTERY COMPLIANCE; ARTERY DIAMETER; COMPUTED TOMOGRAPHIC ANGIOGRAPHY; DIAGNOSTIC IMAGING; ECHOGRAPHY; ENDOVASCULAR ANEURYSM REPAIR; ENDOVASCULAR SURGERY; HEART CYCLE; HUMAN; INTERMETHOD COMPARISON; INTRAVASCULAR ULTRASOUND; MAGNETIC RESONANCE ANGIOGRAPHY; PRIORITY JOURNAL; REVIEW; STENT; SYSTEMATIC REVIEW; THORACIC AORTA; THORACIC AORTA ANEURYSM; AORTOGRAPHY; BLOOD VESSEL PROSTHESIS; BLOOD VESSEL TRANSPLANTATION; COMPUTER ASSISTED TOMOGRAPHY; ENDOSCOPIC ECHOGRAPHY; HEMODYNAMICS; INSTRUMENTATION; METHODOLOGY; PATHOLOGY; PATHOPHYSIOLOGY; PREDICTION AND FORECASTING; PROSTHESIS; TIME; TREATMENT OUTCOME;

EID: 70449704436     PISSN: 10785884     EISSN: 15322165     Source Type: Journal    
DOI: 10.1016/j.ejvs.2009.06.018     Document Type: Review
Times cited : (60)

References (44)
  • 1
    • 5344261145 scopus 로고    scopus 로고
    • A randomized trial comparing conventional and endovascular repair of abdominal aortic aneurysms
    • Prinssen M., Verhoeven E.L., Buth J., Cuypers P.W., van Sambeek M.R., Balm R., et al. A randomized trial comparing conventional and endovascular repair of abdominal aortic aneurysms. N Engl J Med 351 (2004) 1607-1618
    • (2004) N Engl J Med , vol.351 , pp. 1607-1618
    • Prinssen, M.1    Verhoeven, E.L.2    Buth, J.3    Cuypers, P.W.4    van Sambeek, M.R.5    Balm, R.6
  • 2
    • 0028631110 scopus 로고
    • Transluminal placement of endovascular stent-grafts for the treatment of descending thoracic aortic aneurysms
    • Dake M.D., Miller D.C., Semba C.P., Mitchell R.S., Walker P.J., and Liddell R.P. Transluminal placement of endovascular stent-grafts for the treatment of descending thoracic aortic aneurysms. N Engl J Med 331 (1994) 1729-1734
    • (1994) N Engl J Med , vol.331 , pp. 1729-1734
    • Dake, M.D.1    Miller, D.C.2    Semba, C.P.3    Mitchell, R.S.4    Walker, P.J.5    Liddell, R.P.6
  • 3
    • 42749090012 scopus 로고    scopus 로고
    • Five-year results of endovascular treatment with the Gore TAG device compared with open repair of thoracic aortic aneurysms
    • Makaroun M.S., Dillavou E.D., Wheatley G.H., and Cambria R.P. Five-year results of endovascular treatment with the Gore TAG device compared with open repair of thoracic aortic aneurysms. J Vasc Surg 47 (2008) 912-918
    • (2008) J Vasc Surg , vol.47 , pp. 912-918
    • Makaroun, M.S.1    Dillavou, E.D.2    Wheatley, G.H.3    Cambria, R.P.4
  • 4
    • 0033782683 scopus 로고    scopus 로고
    • Incidence and risk factors of late rupture, conversion, and death after endovascular repair of infrarenal aortic aneurysms: the EUROSTAR experience. European collaborators on stent/graft techniques for aortic aneurysm repair
    • Harris P.L., Vallabhaneni S.R., Desgranges P., van Becquemin J.P., and MC Laheij R.J. Incidence and risk factors of late rupture, conversion, and death after endovascular repair of infrarenal aortic aneurysms: the EUROSTAR experience. European collaborators on stent/graft techniques for aortic aneurysm repair. J Vasc Surg 32 (2000) 739-749
    • (2000) J Vasc Surg , vol.32 , pp. 739-749
    • Harris, P.L.1    Vallabhaneni, S.R.2    Desgranges, P.3    van Becquemin, J.P.4    MC Laheij, R.J.5
  • 6
    • 0031044380 scopus 로고    scopus 로고
    • Morphometry and classification in abdominal aortic aneurysms: patient selection for endovascular and open surgery
    • Schumacher H., Eckstein H.H., Kallinowski F., and Allenberg J.R. Morphometry and classification in abdominal aortic aneurysms: patient selection for endovascular and open surgery. J Endovasc Surg 4 (1997) 39-44
    • (1997) J Endovasc Surg , vol.4 , pp. 39-44
    • Schumacher, H.1    Eckstein, H.H.2    Kallinowski, F.3    Allenberg, J.R.4
  • 10
    • 0036481080 scopus 로고    scopus 로고
    • Aortic aneurysm pulsatile wall motion imaged by cine MRI: a tool to evaluate efficacy of endovascular aneurysm repair?
    • Vos A.W., Wisselink W., Marcus J.T., Manoliu R.A., and Rauwerda J.A. Aortic aneurysm pulsatile wall motion imaged by cine MRI: a tool to evaluate efficacy of endovascular aneurysm repair?. Eur J Vasc Endovasc Surg 23 (2002) 158-161
    • (2002) Eur J Vasc Endovasc Surg , vol.23 , pp. 158-161
    • Vos, A.W.1    Wisselink, W.2    Marcus, J.T.3    Manoliu, R.A.4    Rauwerda, J.A.5
  • 11
    • 33745638740 scopus 로고    scopus 로고
    • Dynamic magnetic resonance angiography of the aneurysm neck: conformational changes during the cardiac cycle with possible consequences for endograft sizing and future design
    • van Herwaarden J.A., Bartels L.W., Muhs B.E., Vincken K.L., Lindeboom M.Y.A., Teutelink A., et al. Dynamic magnetic resonance angiography of the aneurysm neck: conformational changes during the cardiac cycle with possible consequences for endograft sizing and future design. J Vasc Surg 44 (2006) 22-28
    • (2006) J Vasc Surg , vol.44 , pp. 22-28
    • van Herwaarden, J.A.1    Bartels, L.W.2    Muhs, B.E.3    Vincken, K.L.4    Lindeboom, M.Y.A.5    Teutelink, A.6
  • 12
    • 33751199363 scopus 로고    scopus 로고
    • Aortic compliance following EVAR and the influence of different endografts: determination using dynamic MRA
    • van Herwaarden J.A., Muhs B.E., Vincken K.L., Van Prehn J., Teutelink A., Bartels L.W., et al. Aortic compliance following EVAR and the influence of different endografts: determination using dynamic MRA. J Endovasc Ther 13 (2006) 406-414
    • (2006) J Endovasc Ther , vol.13 , pp. 406-414
    • van Herwaarden, J.A.1    Muhs, B.E.2    Vincken, K.L.3    Van Prehn, J.4    Teutelink, A.5    Bartels, L.W.6
  • 13
    • 33750101082 scopus 로고    scopus 로고
    • Pilot study of dynamic cine CT angiography for the evaluation of abdominal aortic aneurysms: implications for endograft treatment
    • Teutelink A., Rutten A., Muhs B.E., Olree M., van Herwaarden J.A., de Vos A.M., et al. Pilot study of dynamic cine CT angiography for the evaluation of abdominal aortic aneurysms: implications for endograft treatment. J Endovasc Ther 13 (2006) 139-144
    • (2006) J Endovasc Ther , vol.13 , pp. 139-144
    • Teutelink, A.1    Rutten, A.2    Muhs, B.E.3    Olree, M.4    van Herwaarden, J.A.5    de Vos, A.M.6
  • 14
    • 33847202921 scopus 로고    scopus 로고
    • Use of dynamic computed tomography to evaluate pre- and postoperative aortic changes in AAA patients undergoing endovascular aneurysm repair
    • Teutelink A., Muhs B.E., Vincken K.L., Bartels L.W., Cornelissen S.A., van Herwaarden J.A., et al. Use of dynamic computed tomography to evaluate pre- and postoperative aortic changes in AAA patients undergoing endovascular aneurysm repair. J Endovasc Ther 14 (2007) 44-49
    • (2007) J Endovasc Ther , vol.14 , pp. 44-49
    • Teutelink, A.1    Muhs, B.E.2    Vincken, K.L.3    Bartels, L.W.4    Cornelissen, S.A.5    van Herwaarden, J.A.6
  • 15
    • 4143105842 scopus 로고    scopus 로고
    • Measurement of aortic compliance in abdominal aortic aneurysms before and after open and endoluminal repair: preliminary results
    • Sekhri A.R., Lees W.R., and Adiseshiah M. Measurement of aortic compliance in abdominal aortic aneurysms before and after open and endoluminal repair: preliminary results. J Endovasc Ther 11 (2004) 472-482
    • (2004) J Endovasc Ther , vol.11 , pp. 472-482
    • Sekhri, A.R.1    Lees, W.R.2    Adiseshiah, M.3
  • 16
    • 0031894283 scopus 로고    scopus 로고
    • Reduced pulsatile wall motion of abdominal aortic aneurysms after endovascular repair
    • Malina M., Lanne T., Ivancev K., Lindblad B., and Brunkwall J. Reduced pulsatile wall motion of abdominal aortic aneurysms after endovascular repair. J Vasc Surg 27 (1998) 624-631
    • (1998) J Vasc Surg , vol.27 , pp. 624-631
    • Malina, M.1    Lanne, T.2    Ivancev, K.3    Lindblad, B.4    Brunkwall, J.5
  • 18
    • 10744220966 scopus 로고    scopus 로고
    • Use of cine magnetic resonance angiography in quantifying aneurysm pulsatility associated with endoleak
    • Faries P.L., Agarwal G., Lookstein R., Bernheim J.W., Cayne N.S., Cadot H., et al. Use of cine magnetic resonance angiography in quantifying aneurysm pulsatility associated with endoleak. J Vasc Surg 38 (2003) 652-656
    • (2003) J Vasc Surg , vol.38 , pp. 652-656
    • Faries, P.L.1    Agarwal, G.2    Lookstein, R.3    Bernheim, J.W.4    Cayne, N.S.5    Cadot, H.6
  • 19
    • 7744232846 scopus 로고    scopus 로고
    • Pulsatile wall motion (PWM) measurements after endovascular abdominal aortic aneurysm exclusion are not useful in the classification of endoleak
    • Lindblad B., Dias N., Malina M., Ivancev K., Resch T., Hansen F., et al. Pulsatile wall motion (PWM) measurements after endovascular abdominal aortic aneurysm exclusion are not useful in the classification of endoleak. Eur J Vasc Endovasc Surg 28 (2004) 623-628
    • (2004) Eur J Vasc Endovasc Surg , vol.28 , pp. 623-628
    • Lindblad, B.1    Dias, N.2    Malina, M.3    Ivancev, K.4    Resch, T.5    Hansen, F.6
  • 20
    • 0034685429 scopus 로고    scopus 로고
    • Meta-analysis of observational studies in epidemiology: a proposal for reporting. Meta-analysis Of Observational Studies in Epidemiology (MOOSE) group
    • Stroup D.F., Berlin J.A., Morton S.C., Olkin I., Williamson G.D., Rennie D., et al. Meta-analysis of observational studies in epidemiology: a proposal for reporting. Meta-analysis Of Observational Studies in Epidemiology (MOOSE) group. JAMA 283 (2000) 2008-2012
    • (2000) JAMA , vol.283 , pp. 2008-2012
    • Stroup, D.F.1    Berlin, J.A.2    Morton, S.C.3    Olkin, I.4    Williamson, G.D.5    Rennie, D.6
  • 21
    • 47549116838 scopus 로고    scopus 로고
    • Impact of aortic dimensions and pulse pressure on late aneurysm formation in operated type A aortic dissection. A magnetic resonance imaging study
    • Almeida A.G., Nobre A.L., Pereira R.A., Costa-Pereira A., Tavares C., Cravino J., et al. Impact of aortic dimensions and pulse pressure on late aneurysm formation in operated type A aortic dissection. A magnetic resonance imaging study. Int J Cardiovasc Imaging 24 (2008) 633-640
    • (2008) Int J Cardiovasc Imaging , vol.24 , pp. 633-640
    • Almeida, A.G.1    Nobre, A.L.2    Pereira, R.A.3    Costa-Pereira, A.4    Tavares, C.5    Cravino, J.6
  • 22
    • 0346964280 scopus 로고    scopus 로고
    • Time-resolved magnetic resonance angiography as a noninvasive method to characterize endoleaks: initial results compared with conventional angiography
    • Lookstein R.A., Goldman J., Pukin L., and Marin M.L. Time-resolved magnetic resonance angiography as a noninvasive method to characterize endoleaks: initial results compared with conventional angiography. J Vasc Surg 39 (2004) 27-33
    • (2004) J Vasc Surg , vol.39 , pp. 27-33
    • Lookstein, R.A.1    Goldman, J.2    Pukin, L.3    Marin, M.L.4
  • 23
    • 8544246410 scopus 로고    scopus 로고
    • Characterization of endoleaks by dynamic computed tomographic angiography
    • Rydberg J., Lalka S., Johnson M., Cikrit D., Dalsing M., Sawchuk A., et al. Characterization of endoleaks by dynamic computed tomographic angiography. Am J Surg 188 (2004) 538-543
    • (2004) Am J Surg , vol.188 , pp. 538-543
    • Rydberg, J.1    Lalka, S.2    Johnson, M.3    Cikrit, D.4    Dalsing, M.5    Sawchuk, A.6
  • 24
    • 49749135497 scopus 로고    scopus 로고
    • Simultaneous sizing and preoperative risk stratification for thoracic endovascular aneurysm repair: role of gated computed tomography
    • Schlosser F.J., Mojibian H.R., Dardik A., Verhagen H.J., Moll F.L., and Muhs B.E. Simultaneous sizing and preoperative risk stratification for thoracic endovascular aneurysm repair: role of gated computed tomography. J Vasc Surg (2008)
    • (2008) J Vasc Surg
    • Schlosser, F.J.1    Mojibian, H.R.2    Dardik, A.3    Verhagen, H.J.4    Moll, F.L.5    Muhs, B.E.6
  • 25
    • 0033785947 scopus 로고    scopus 로고
    • Pulsatile wall motion and blood pressure in aneurysms with open and thrombosed endoleaks - comparison of a wall track system and M-mode ultrasound scanning: an in vitro and animal study
    • Schurink G.W., Aarts N.J., Malina M., and van Bockel J.H. Pulsatile wall motion and blood pressure in aneurysms with open and thrombosed endoleaks - comparison of a wall track system and M-mode ultrasound scanning: an in vitro and animal study. J Vasc Surg 32 (2000) 795-803
    • (2000) J Vasc Surg , vol.32 , pp. 795-803
    • Schurink, G.W.1    Aarts, N.J.2    Malina, M.3    van Bockel, J.H.4
  • 26
    • 35948961627 scopus 로고    scopus 로고
    • Segment movement of abdominal aorta aneurysmal wall: observation by color kinesis and ICK(trademark) Quantitative Analysis System
    • Chen Q., Ye Y., Bao J.M., Jing Z.P., Mei Z.J., and Zhao B.Z. Segment movement of abdominal aorta aneurysmal wall: observation by color kinesis and ICK(trademark) Quantitative Analysis System. J Clin Rehabil Tissue Eng Res 11 (2007) 7024-7027
    • (2007) J Clin Rehabil Tissue Eng Res , vol.11 , pp. 7024-7027
    • Chen, Q.1    Ye, Y.2    Bao, J.M.3    Jing, Z.P.4    Mei, Z.J.5    Zhao, B.Z.6
  • 27
    • 34848875493 scopus 로고    scopus 로고
    • Increased anterior abdominal aortic wall motion: possible role in aneurysm pathogenesis and design of endovascular devices
    • Goergen C.J., Johnson B.L., Greve J.M., Taylor C.A., and Zarins C.K. Increased anterior abdominal aortic wall motion: possible role in aneurysm pathogenesis and design of endovascular devices. J Endovasc Ther 14 (2007) 574-584
    • (2007) J Endovasc Ther , vol.14 , pp. 574-584
    • Goergen, C.J.1    Johnson, B.L.2    Greve, J.M.3    Taylor, C.A.4    Zarins, C.K.5
  • 28
    • 0030203275 scopus 로고    scopus 로고
    • Cine magnetic resonance imaging study of blood flow and wall motion of the aortic arch
    • Yoshii S., Mohri N., Kamiya K., and Tada Y. Cine magnetic resonance imaging study of blood flow and wall motion of the aortic arch. Jpn Circ J 60 (1996) 553-559
    • (1996) Jpn Circ J , vol.60 , pp. 553-559
    • Yoshii, S.1    Mohri, N.2    Kamiya, K.3    Tada, Y.4
  • 29
    • 0031871736 scopus 로고    scopus 로고
    • Relationship between abdominal aortic aneurysm wall compliance and clinical outcome: a preliminary analysis
    • Wilson K., Bradbury A., Whyman M., Hoskins P., Lee A., Fowkes G., et al. Relationship between abdominal aortic aneurysm wall compliance and clinical outcome: a preliminary analysis. Eur J Vasc Endovasc Surg 15 (1998) 472-477
    • (1998) Eur J Vasc Endovasc Surg , vol.15 , pp. 472-477
    • Wilson, K.1    Bradbury, A.2    Whyman, M.3    Hoskins, P.4    Lee, A.5    Fowkes, G.6
  • 30
    • 35548969296 scopus 로고    scopus 로고
    • Dynamic geometry and wall thickness of the aortic neck of abdominal aortic aneurysms with intravascular ultrasonography
    • Arko F.R., Murphy E.H., vis III C.M., Johnson E.D., Smith S.T., and Zarins C.K. Dynamic geometry and wall thickness of the aortic neck of abdominal aortic aneurysms with intravascular ultrasonography. J Vasc Surg 46 (2007) 891-897
    • (2007) J Vasc Surg , vol.46 , pp. 891-897
    • Arko, F.R.1    Murphy, E.H.2    vis III, C.M.3    Johnson, E.D.4    Smith, S.T.5    Zarins, C.K.6
  • 31
    • 52049112759 scopus 로고    scopus 로고
    • Quantification of aortic distensibility in abdominal aortic aneurysm using ECG-gated multi-detector computed tomography
    • Ganten M.K., Krautter U., von Tengg-Kobligk H., Bockler D., Schumacher H., Stiller W., et al. Quantification of aortic distensibility in abdominal aortic aneurysm using ECG-gated multi-detector computed tomography. Eur Radiol 18 (2008) 966-973
    • (2008) Eur Radiol , vol.18 , pp. 966-973
    • Ganten, M.K.1    Krautter, U.2    von Tengg-Kobligk, H.3    Bockler, D.4    Schumacher, H.5    Stiller, W.6
  • 34
    • 0032955376 scopus 로고    scopus 로고
    • The relationship between abdominal aortic aneurysm wall compliance, maximum diameter and growth rate
    • Wilson K., Whyman M., Hoskins P., Lee A.J., Bradbury A.W., Fowkes F.G., et al. The relationship between abdominal aortic aneurysm wall compliance, maximum diameter and growth rate. Cardiovasc Surg 7 (1999) 208-213
    • (1999) Cardiovasc Surg , vol.7 , pp. 208-213
    • Wilson, K.1    Whyman, M.2    Hoskins, P.3    Lee, A.J.4    Bradbury, A.W.5    Fowkes, F.G.6
  • 36
    • 0034809371 scopus 로고    scopus 로고
    • Comparison of brachial artery pressure and derived central pressure in the measurement of abdominal aortic aneurysm distensibility
    • Wilson K., MacCallum H., Wilkinson I.B., Hoskins P.R., Lee A.J., and Bradbury A.W. Comparison of brachial artery pressure and derived central pressure in the measurement of abdominal aortic aneurysm distensibility. Eur J Vasc Endovasc Surg 22 (2001) 355-360
    • (2001) Eur J Vasc Endovasc Surg , vol.22 , pp. 355-360
    • Wilson, K.1    MacCallum, H.2    Wilkinson, I.B.3    Hoskins, P.R.4    Lee, A.J.5    Bradbury, A.W.6
  • 37
    • 33749330405 scopus 로고    scopus 로고
    • Dynamic cine-CT angiography for the evaluation of the thoracic aorta; insight in dynamic changes with implications for thoracic endograft treatment
    • Muhs B.E., Vincken K.L., Van Prehn J., Stone M.K.C., Bartels L.W., Prokop M., et al. Dynamic cine-CT angiography for the evaluation of the thoracic aorta; insight in dynamic changes with implications for thoracic endograft treatment. Eur J Vasc Endovasc Surg 32 (2006) 532-536
    • (2006) Eur J Vasc Endovasc Surg , vol.32 , pp. 532-536
    • Muhs, B.E.1    Vincken, K.L.2    Van Prehn, J.3    Stone, M.K.C.4    Bartels, L.W.5    Prokop, M.6
  • 39
    • 67349127334 scopus 로고    scopus 로고
    • Dynamic aortic changes in patients with thoracic aortic aneurysms evaluated with electrocardiography-triggered computed tomographic angiography before and after thoracic endovascular aneurysm repair: preliminary results
    • van Prehn J., Bartels L.W., Mestres G., Vincken K.L., Prokop M., Verhagen H.J., et al. Dynamic aortic changes in patients with thoracic aortic aneurysms evaluated with electrocardiography-triggered computed tomographic angiography before and after thoracic endovascular aneurysm repair: preliminary results. Ann Vasc Surg (2008)
    • (2008) Ann Vasc Surg
    • van Prehn, J.1    Bartels, L.W.2    Mestres, G.3    Vincken, K.L.4    Prokop, M.5    Verhagen, H.J.6
  • 40
    • 0034754030 scopus 로고    scopus 로고
    • Micromovements at the aortic aneurysm neck measured during open surgery with close-range photogrammetry: implications for aortic endografts
    • Flora H.S., Woodhouse N., Robson S., and Adiseshiah M. Micromovements at the aortic aneurysm neck measured during open surgery with close-range photogrammetry: implications for aortic endografts. J Endovasc Ther 8 (2001) 511-520
    • (2001) J Endovasc Ther , vol.8 , pp. 511-520
    • Flora, H.S.1    Woodhouse, N.2    Robson, S.3    Adiseshiah, M.4
  • 41
    • 33748847758 scopus 로고    scopus 로고
    • Endovascular aneurysm repair alters renal artery movement: a preliminary evaluation using dynamic CTA
    • Muhs B.E., Teutelink A., Prokop M., Vincken K.L., Moll F.L., and Verhagen H.J.M. Endovascular aneurysm repair alters renal artery movement: a preliminary evaluation using dynamic CTA. J Endovasc Ther 13 (2006) 476-480
    • (2006) J Endovasc Ther , vol.13 , pp. 476-480
    • Muhs, B.E.1    Teutelink, A.2    Prokop, M.3    Vincken, K.L.4    Moll, F.L.5    Verhagen, H.J.M.6
  • 42
    • 38649114986 scopus 로고    scopus 로고
    • Dynamic cine-computed tomography angiography imaging of standard and fenestrated endografts: differing effects on renal artery motion
    • Muhs B.E., Vincken K.L., Teutelink A., Verhoeven E.L.G., Prokop M., and Moll F.L. Dynamic cine-computed tomography angiography imaging of standard and fenestrated endografts: differing effects on renal artery motion. J Vasc Endovasc Surg 42 (2008) 25-31
    • (2008) J Vasc Endovasc Surg , vol.42 , pp. 25-31
    • Muhs, B.E.1    Vincken, K.L.2    Teutelink, A.3    Verhoeven, E.L.G.4    Prokop, M.5    Moll, F.L.6
  • 43
    • 0034016773 scopus 로고    scopus 로고
    • Ultrasonic measurement of abdominal aortic aneurysm wall compliance: a reproducibility study
    • Wilson K.A., Hoskins P.R., Lee A.J., Fowkes F.G., Ruckley C.V., and Bradbury A.W. Ultrasonic measurement of abdominal aortic aneurysm wall compliance: a reproducibility study. J Vasc Surg 31 (2000) 507-513
    • (2000) J Vasc Surg , vol.31 , pp. 507-513
    • Wilson, K.A.1    Hoskins, P.R.2    Lee, A.J.3    Fowkes, F.G.4    Ruckley, C.V.5    Bradbury, A.W.6


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.