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- Cinthio, Magnus, et al.
(författare)
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New improved and modified method for measurements of arterial wall movements in longitudinal and radial directions
- 2005
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Ingår i: Medical physics : proceedings of the jointly held congresses ICMP 2005, 14th International Conference of the Medical Physics of the International Organization for Medical Physics (IOMP), the European Federation of Organisations in Medical Physics (EFOMP) and the German Society of Medical Physics (DGMP) [and] BMT 2005, 39th annual congress of the German Society for Biomedical Engineering (DGBMT) ; 14th - 17th September 2005, Nuremberg, Germany. ; 50, s. 869-870
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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- Eriksson, Magnus G., et al.
(författare)
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Haptic Simulation of the Milling Process in Temporal Bone Operations
- 2005
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Ingår i: Medicine Meets Virtual Reality 13. - : IOS Press. - 9781586034986 ; , s. 133-136
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Konferensbidrag (refereegranskat)abstract
- A VR-simulation system for educating surgeons of the temporal bone milling processes is presented in this paper. E. g. the milling process that occurs during the removal of certain cancer tumors in the brain. The research project is recently started up and this paper is an introduction to the bone milling simulation topic. We present how the graphical rendering of the temporal bone is done. Acquired data are managed using the Marching cubes algorithm to perform a visual representation. A re-production of iso-surfaces will represent the material removal occurred during the milling process. Force models are discussed and will be implemented in the H3D API, which is used to control the virtual simulation and collision detection. Equipment, implementation and future work are also presented in the paper.
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- Govind, Satish C., et al.
(författare)
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Isolated Type 2 Diabetes mellitus Causes Myocardial Dysfunction That Becomes Worse in the Presence of Cardiovascular Diseases : Results of the Myocardial Doppler in Diabetes (MYDID): Study 1
- 2005
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Ingår i: Cardiology. - : S. Karger AG. - 0008-6312 .- 1421-9751. ; 103:4, s. 189-195
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Tidskriftsartikel (refereegranskat)abstract
- Aims: Patients with type 2 diabetes mellitus (DM) often suffer disproportionately and have a worse outcome when burdened with cardiovascular complications compared with those without DM. A specific heart muscle disease reportedly caused by DM per se may explain this. We sought to investigate whether an echo Doppler diagnosis of such a myocardial disease is clinically relevant in DM with or without coexistent coronary artery disease (CAD) and/or hypertension ( HTN). Subjects and Methods: Two hundred subjects (127 males, 73 females, 56 +/- 10 years) including controls (n=23), patients with HTN (n=20), CAD (n=35), uncomplicated DM (n=59), DM+HTN (n=27), DM+ CAD (n=16) and DM+CAD+HTN (n=20) underwent tissue Doppler-enhanced dobutamine stress echocardiography. Myocardial function was assessed by measuring left ventricular myocardial peak systolic velocity (PSV) and early diastolic velocity at rest and during peak stress, besides measurements of standard Doppler variables. Results: Average left ventricular PSV at rest was significantly lower in CAD (4.7 +/- 1.5) compared with controls (5.7 center dot +/- 1.2) and in DM+CAD+HTN (4.6 +/- 1.4) compared with DM (5.6 +/- 1.3; all p < 0.05). During peak stress, lower PSV persisted in CAD (9.5 +/- 3.1) and DM+CAD+HTN (8.1 +/- 2.7), while appearing de novo in DM (11.3 +/- 2.6) and HTN (11.0 +/- 2.3) unlike in the controls (12.5 +/- 2.5; all p < 0.001). When pooled together, DM subjects with CAD and/or HTN or both had significantly lower PSV (9.1 +/- 2.7) than those without (10.0 +/- 2.8; p < 0.001). Early diastolic velocity response was equally lower in both groups compared with the controls. Conclusion: The results suggest that dobutamine stress unmasks myocardial functional disturbances caused by uncomplicated DM. The discrete disturbances become quantitatively more pronounced in the presence of coexistent cardiovascular diseases.
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- Karlsson, Daniel M. G., et al.
(författare)
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Myocardial perfusion monitoring during coronary artery bypass using an electrocardiogram-triggered laser Doppler technique
- 2005
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Ingår i: Medical and Biological Engineering and Computing. - : Springer. - 0140-0118 .- 1741-0444. ; 43:5, s. 582-588
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Tidskriftsartikel (refereegranskat)abstract
- Electrocardiogram (ECG)—triggered laser Doppler perfusion monitoring (LDPM) was used to assess myocardial perfusion, with minimum myocardial tissue motion influence, during coronary artery bypass grafting (CABG). Thirteen subjects were investigated at six phases: pre- and post-CABG; post aorta cross-clamping; pre and post left internal mammary artery (LIMA) graft declamping; and post aorta declamping. The perfusion signal was calculated in late systole and late diastole, with expected minimum tissue motion, and compared with arrested heart measurements. Patient conditions or artifacts caused by surgical activity made it impossible to perform and analyse data in all six phases for some patients. No significant (n=5) difference between perfusion signals pre- and post-CABG was found. Diastolic perfusion signal levels were significantly (p<0.02) lower compared with systolic levels. After aorta cross-clamping, the signal level was almost zero. A distinct perfusion signal increase after LIMA and aorta declamping, compared with pre-LIMA declamping, was found in ten cases out of 13. A significantly (p<0.04) lower perfusion signal in the arrested heart compared with in the beating heart was registered. Influence from mechanical ventilation was observed in 14 measurements out of 17. In conclusion, ECG-triggered LDPM can be used to assess myocardial perfusion during CABG. Perfusion signals were lower in the arrested heart compared with in the beating heart and in late diastole compared with late systole. No significant difference between pre- and post-CABG was found.
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- Karlsson, Daniel M G, 1974-, et al.
(författare)
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Polarized laser Doppler perfusion imaging—reduction of movement-induced artifacts
- 2005
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Ingår i: Journal of Biomedical Optics. - : SPIE - International Society for Optical Engineering. - 1083-3668 .- 1560-2281. ; 10:6
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Tidskriftsartikel (refereegranskat)abstract
- Laser Doppler perfusion imaging (LDPI) enables superficial tissue perfusion assessment, but is sensitive to tissue motion not related to blood cells. The aim was to investigate if a polarization technique could reduce movement-induced artifacts. A linearly polarized laser and a cross-polarized filter, placed in front of the detectors, were used to block specular reflection. Measurements were performed with, and without, the polarization filter, at a single site during horizontal and vertical movement of skin tissue (index finger, twelve subjects, n=112) and of a flow model (n=432), with varying surface structures. Measurements were repeated during different flow conditions and at increased skin specular reflection. Statistical analysis was performed using ANOVA models. The perfusion signal was lower (p<0.001, skin and p<0.05, flow model) using the polarization filter, due to movement artifact reduction. No significant influence from surface structure was found when using the polarization filter. Movement artifacts were lower (p<0.05) in the vertical movement direction, however, depending on flow conditions for skin measurements. Increased skin specular reflection gave rise to large movement artifacts without the polarization filter. In conclusion, the polarized LDPI technique reduces movement artifacts and is particularly appropriate when assessing, e.g., ulcers and burns, where specular reflection is high.
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- Kronander, Håkan, et al.
(författare)
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Improved capacity of exercise electrocardiography in the detection of coronary artery disease by focusing on diagnostic variables during the early recovery phase
- 2005
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Ingår i: Journal of Electrocardiology. - : Elsevier BV. - 0022-0736 .- 1532-8430. ; 38:2, s. 130-138
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Tidskriftsartikel (refereegranskat)abstract
- The temporal distribution of the diagnostic information for the detection of coronary artery disease (CAD) provided by exercise-induced electrocardiographic (ECG) ST-segment amplitude changes in different ECG leads in men and women has not been fully investigated. To shed further light in this area, 1877 electrocardiograms selected from 8322 patients undergoing a routine exercise test on a bicycle ergometer were evaluated. ST-segment amplitude and the difference between heart rate-matched recovery and exercise ST-segment amplitudes (ST/HR difference) were measured. Coronary artery disease was verified angiographically in 669 patients and excluded in 1208 patients by angiography (n = 119), by myocardial scintigraphy (n = 250), or on clinical grounds (n = 839). The diagnostic performance of the 2 ECG methods used was assessed by constructing receiver operating characteristic curves for each sampling point every 12 seconds during 10 minutes of recovery as well as the last 4 minutes of exercise for the ST-segment amplitude. ST-segment amplitude performed better after exercise than during exercise and best within the first 2 minutes of recovery. Its diagnostic ability did not differ from the ST-amplitude hysteresis assessed by the difference between recovery ST-segment amplitude and exercise ST-segment amplitude at matched heart rate. Both methods performed better in men and the diagnostic information appeared mainly in leads I, -aVR, II, V-4, V-5, and V-6. The best discrimination of CAD is provided by analysis of ST-segment amplitude changes in 6 specific leads early during the recovery phase. This information should be targeted by exercise ECG diagnostic methods.
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