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Muscle Perfusion (muscle + perfusion)
Selected AbstractsNon-invasive monitoring of muscle blood perfusion by photoplethysmography: evaluation of a new applicationACTA PHYSIOLOGICA, Issue 4 2005M. Sandberg Abstract Aim:, To evaluate a specially developed photoplethysmographic (PPG) technique, using green and near-infrared light sources, for simultaneous non-invasive monitoring of skin and muscle perfusion. Methods:, Evaluation was based on assessments of changes in blood perfusion to various provocations, such as post-exercise hyperaemia and hyperaemia following the application of liniment. The deep penetrating feature of PPG was investigated by measurement of optical radiation inside the muscle. Simultaneous measurements using ultrasound Doppler and the new PPG application were performed to elucidate differences between the two methods. Specific problems related to the influence of skin temperature on blood flow were highlightened, as well. Results:, Following static and dynamic contractions an immediate increase in muscle perfusion was shown, without increase in skin perfusion. Liniment application to the skin induced a rapid increase in skin perfusion, but not in muscle. Both similarities and differences in blood flow measured by Ultrasound Doppler and PPG were demonstrated. The radiant power measured inside the muscle, by use of an optical fibre, showed that the near-infrared light penetrates down to the vascular depth inside the muscle. Conclusions:, The results of this study indicate the potentiality of the method for non-invasive measurement of local muscle perfusion, although some considerations still have to be accounted for, such as influence of temperature on blood perfusion. [source] Improved survival of rat ischemic cutaneous and musculocutaneous flaps after VEGF gene transferMICROSURGERY, Issue 5 2007Andrea Antonini M.D. When harvesting microsurgical flaps, the main goals are to obtain as much tissue as possible based on a single vascular pedicle and a reliable vascularization of the entire flap. These aims being in contrast to each other, microsurgeons have been looking for an effective way to enhance skin and muscle perfusion in order to avoid partial flap loss in reconstructive surgery. In this study we demonstrate the efficacy of VEGF 165 delivered by an Adeno-Associated Virus (AAV) vector in two widely recognized rat flap models. In the rectus abdominis miocutaneous flap, intramuscular injection of AAV- VEGF reduced flap necrosis by 50%, while cutaneous delivery of the same amount of vector put down the epigastric flap's ischemia by >40%. Histological evidence of neoangiogenesis (enhanced presence of CD31-positive capillaries and ,-Smooth Muscle Actin-positive arteriolae) confirmed the therapeutic effect of AAV- VEGF on flap perfusion. © 2007 Wiley-Liss, Inc. Microsurgery, 2007. [source] Dynamic contrast-enhanced MRI of muscle perfusion combined with MR angiography of collateral artery growth in a femoral artery ligation modelNMR IN BIOMEDICINE, Issue 8 2007Quido G. de Lussanet Abstract To assess the use of MRI for evaluating changes in muscle blood flow and number of collateral arteries, serial dynamic contrast-enhanced MRI (DCE-MRI) was combined with high-spatial-resolution contrast-enhanced MR angiography (MRA) in a peripheral ischemia model. The combined MRI (DCE-MRI and MRA) protocol was performed serially in 15 male rabbits at 2,h (day 0+), 7 days, and 21 days after femoral artery ligation. In the anterior tibial and soleus muscle, changes in resting muscle blood flow determined as the endothelial transfer coefficient (Ktrans) and arterial inflow delay from DCE-MRI and changes in the number of sub-millimeter sized collateral arteries as scored with MRA were measured. Directly after ligation, Ktrans in the anterior tibial muscle was reduced to 23% of that in the control limb, then recovered to 81% on day 7, and to 85 % on day 21. Ktrans in the soleus muscle recovered from a reduction to 63% on day 0+, to 85% on day 7, and to 90% on day 21. The number of collaterals around the ligated femoral artery increased from 1.1 on day 0+ to 4.2 on day 7, and 6.0 on day 21 in the ligated limb only. Combined DCE-MRI and MRA allows non-invasive serial monitoring of changes in muscle blood flow and growth of sub-millimeter sized collateral arteries in a rabbit femoral artery ligation model. Copyright © 2007 John Wiley & Sons, Ltd. [source] Validation and advantages of FAWSETS perfusion measurements in skeletal muscleNMR IN BIOMEDICINE, Issue 4 2005Kenneth I. Marro Abstract This work discusses the strengths, limitations and validity of a novel arterial spin labeling technique when used specifically to measure perfusion in limb skeletal muscle. The technique, flow-driven arterial water stimulation with elimination of tissue signal (FAWSETS), offers several advantages over existing arterial spin labeling techniques. The primary goal of this study was to determine the perfusion signal response to changes in net hind limb flow that were independently verifiable. The range of perfusate flow was relevant to skeletal muscle during mild to moderate exercise. Localized, single voxel measurements were acquired from a 5,mm-thick slice in the isolated perfused rat hind limb at variable net flow rates. The results show that the perfusion signal is linearly proportional to net hind limb flow with a correlation coefficient of 0.974 (p,=,0.0013). FAWSETS is especially well suited for studies of skeletal muscle perfusion, where it eliminates the need to compensate for magnetization transfer and arterial transit time effects. A conceptual discussion of the basic principles underlying these advantages is presented. Copyright © 2005 John Wiley & Sons, Ltd. [source] Haemodynamic responses to exercise, ATP infusion and thigh compression in humans: insight into the role of muscle mechanisms on cardiovascular functionTHE JOURNAL OF PHYSIOLOGY, Issue 9 2008José González-Alonso The muscle pump and muscle vasodilatory mechanims are thought to play important roles in increasing and maintaining muscle perfusion and cardiac output during exercise, but their actual contributions remain uncertain. To evaluate the role of the skeletal muscle pump and vasodilatation on cardiovascular function during exercise, we determined leg and systemic haemodynamic responses in healthy men during (1) incremental one-legged knee-extensor exercise, (2) step-wise femoral artery ATP infusion at rest, (3) passive exercise (n= 10), (4) femoral vein or artery ATP infusion (n= 6), and (5) cyclic thigh compressions at rest and during passive and voluntary exercise (n= 7). Incremental exercise resulted in progressive increases in leg blood flow (,LBF 7.4 ± 0.7 l min,1), cardiac output ( 8.7 ± 0.7 l min,1), mean arterial pressure (,MAP 51 ± 5 mmHg), and leg and systemic oxygen delivery and . Arterial ATP infusion resulted in similar increases in , LBF, and systemic and leg oxygen delivery, but central venous pressure and muscle metabolism remained unchanged and MAP was reduced. In contrast, femoral vein ATP infusion did not alter LBF, or MAP. Passive exercise also increased blood flow (,LBF 0.7 ± 0.1 l min,1), yet the increase in muscle and systemic perfusion, unrelated to elevations in aerobic metabolism, accounted only for ,5% of peak exercise hyperaemia. Likewise, thigh compressions alone or in combination with passive exercise increased blood flow (,LBF 0.5,0.7 l min,1) without altering , MAP or . These findings suggest that the skeletal muscle pump is not obligatory for sustaining venous return, central venous pressure, stroke volume and or maintaining muscle blood flow during one-legged exercise in humans. Further, its contribution to muscle and systemic peak exercise hyperaemia appears to be minimal in comparison to the effects of muscle vasodilatation. [source] Muscle fractal vascular branching pattern and microvascular perfusion heterogeneity in endurance-trained and untrained menTHE JOURNAL OF PHYSIOLOGY, Issue 2 2003Kari K. Kalliokoski Less heterogeneous skeletal muscle perfusion has recently been reported in endurance-trained compared to untrained men at macrovascular level. The causes of this difference in perfusion heterogeneity are unknown as is whether the same difference is observed in microvasculature. We hypothesised that the difference could be caused by changes in muscle vascular branching pattern. Perfusion was measured in resting and exercising muscle in 14 endurance-trained and seven untrained men using [15O]water and positron emission tomography. Fractal dimension (D) of perfusion distribution was calculated as a measure of fractal characteristics of muscle vascular branching pattern. Perfusion heterogeneity in microvascular units (1 mm3 samples) was estimated using the measured heterogeneity in voxels of positron emission tomography (PET) images (relative dispersion, RD =s.d./mean) and corresponding D values. D was similar between the groups (exercising muscle 1.11 ± 0.07 and 1.14 ± 0.06, resting muscle 1.12 ± 0.06 and 1.14 ± 0.03, trained and untrained, respectively). Trained men had lower perfusion (151 ± 44 vs. 218 ± 87 ml min,1 kg,1, P < 0.05) and macrovascular perfusion heterogeneity (relative dispersion 21 ± 5 vs. 25 ± 5 %, P < 0.05) in exercising muscle than untrained men. Furthermore, estimated perfusion heterogeneity in microvascular units in exercising muscle was also lower in trained men (33 ± 7 vs.48 ± 19 %, P < 0.05). These results show that fractal vascular branching pattern is similar in endurance-trained and untrained men but perfusion is less heterogeneous at both the macro- and the microvascular level in endurance-trained men. Thus, changes in fractal branching pattern do not explain the differences in perfusion heterogeneity between endurance-trained and untrained men. [source] | |||||||||||||