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Influence of tissue movement on laser Doppler perfusion imaging
Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Tekniska högskolan.
Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Tekniska högskolan.ORCID-id: 0000-0001-6385-6760
Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Tekniska högskolan.
Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Tekniska högskolan.ORCID-id: 0000-0002-0012-7867
2002 (engelsk)Inngår i: Proc. SPIE 4624, Optical Diagnostics and Sensing of Biological Fluids and Glucose and Cholesterol Monitoring II, 106 (May 24, 2002), Vol. 4624 / [ed] Alexander V. Priezzhev and Gerard L. Cote, SPIE , 2002, s. 106-114Konferansepaper, Publicerat paper (Fagfellevurdert)
Abstract [en]

The microvascular perfusion can be measured using laser Doppler blood flowmetry (LDF), a technique sensitive to the concentration of moving blood cells and their velocity. However, movements of the tissue itself can cause artifacts in the perfusion readings. In a clinical situation, these movement induced artifacts may arise from patient movements or from movements of internal organs e.g. the intestines or the beating heart. Therefore, we have studied how a well-controlled tissue movement affects the LDF signals during different flow conditions and for different surface structures. Tissue perfusion was recorded non-touch in one point using a laser Doppler perfusion imager. During the measurements the object was placed on a shaker that generated the movement (both horizontal and vertical). Measurements were carried out both on DELRIN® (polyacetal plastic) and the fingertip, for a wide range of velocities (0-3 cm/s). The influence of the microvascular perfusion was evaluated by occluding the brachial artery as well as blood emptying the finger and by using a flow model. The LDF signals were correlated to the movement. In vivo measurements showed that velocities above 0.8 cm/s gave a significant contribution to the perfusion signal. Corresponding velocities for the DELRIN® piece were higher (1.4 – 2.6 cm/s), and dependent on the surface structures and reflecting properties. By reducing the amount of specular reflection the movement influence was substantially lowered.

sted, utgiver, år, opplag, sider
SPIE , 2002. s. 106-114
HSV kategori
Identifikatorer
URN: urn:nbn:se:liu:diva-31098DOI: 10.1117/12.468313Lokal ID: 16829OAI: oai:DiVA.org:liu-31098DiVA, id: diva2:251921
Konferanse
Optical Diagnostics and Sensing of Biological Fluids and Glucose and Cholesterol Monitoring II, San Jose, CA, USA, January 19, 2002
Tilgjengelig fra: 2009-10-09 Laget: 2009-10-09 Sist oppdatert: 2016-08-31bibliografisk kontrollert
Inngår i avhandling
1. Movement artifact reduction in laser Doppler blood flowmetry: myocardial perfusion applications
Åpne denne publikasjonen i ny fane eller vindu >>Movement artifact reduction in laser Doppler blood flowmetry: myocardial perfusion applications
2005 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
Abstract [en]

Laser Doppler perfusion monitoring (LDPM) and imaging (LDPI) enable assessment of tissue microvascular perfusion. The techniques are based on the Doppler broadening of the optical spectrum occurring when coherent laser light is scattered by moving red blood cells (RBC). However, if tissue motion not related to moving RBCs is present, artifacts arise in the derived perfusion estimate. The aim of this thesis was to develop and evaluate methods to reduce tissue motion influence on the perfusion estimate in general and for the specific purpose of enabling myocardial perfusion monitoring in the beating heart.

An LDPM system, based on digital signal processing, was developed for myocardial perfusion assessment. To achieve an accurate estimate of the local microvascular perfusion, the varying myocardial tissue motion during the cardiac cycle is taken into account. By means of ECG-triggering, periods of minimum myocardial tissue motion can be pinpointed. The system and proposed methods were successfully evaluated both in an animal model (3 calves) and during coronary artery bypass grafting (CABG) on 13 humans. Animal studies showed the importance of processing during minimum tissue motion, at late diastole and/or late systole, to reduce movement artifacts. The human evaluation confirmed earlier animal findings and revealed low flow situations in the intraoperative phase. Influence of mechanical ventilation on the myocardial blood flow was found. The results justify investigation postoperative of CABG, where myocardial perfusion monitoring may give a rapid response to potential ischemia.

The influence of tissue motion on LDPI was studied in model measurements and on the skin. A relatively large tissue velocity, compared to microvascular flow velocities, was needed to significantly influence the perfusion signal. Movement artifact magnitude depended on the movement direction and the surface structure. An LDPI system utilizing a polarization technique that blocks specularly reflected light is proposed. The method was evaluated in a flow model and on the skin of 12 subjects and was found to significantly reduce influence from tissue motion. Finally, a theoretical explanation of the origin of LDPI movement artifacts is proposed. Reduction of movement artifacts makes measurements more reliable and increases the potential of LDPI as a clinical tool.

sted, utgiver, år, opplag, sider
Linköping: Linköpings universitet, 2005. s. 84
Serie
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 935
HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-28804 (URN)13992 (Lokal ID)91-85297-73-9 (ISBN)13992 (Arkivnummer)13992 (OAI)
Disputas
2005-04-29, Linden, ingång 65, Campus US, Linköpings universitet, Linköping, 09:15 (engelsk)
Opponent
Veileder
Tilgjengelig fra: 2009-10-09 Laget: 2009-10-09 Sist oppdatert: 2018-01-08bibliografisk kontrollert

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