Current methods of clinical assessment of muscle coordination and function after stroke do not pr... more Current methods of clinical assessment of muscle coordination and function after stroke do not provide information on deep muscles. The objective of this study was to examine how stroke affects both superficial and deep muscles' coordination and whether muscle function improves after rehabilitation. Muscle function, coordination, and activity of quadriceps femoris (QF) and hamstrings were evaluated in 10 stroke patients with mild hemiparesis and in 6 controls using velocity-encoded cine phase-contrast magnetic resonance imaging (VE-PC MRI), surface electromyography (sEMG), and maximal voluntary isometric contraction torque (MVC). At baseline, the peak muscle velocity of the rectus femoris (RF) and the ratio between the peak velocities of the RF and vasti were lower in the affected limb (AL) of stroke patients than in controls. Co-contraction of agonists and antagonists was higher in the AL than in controls. Muscle activity measured by sEMG showed similar behavior. After rehabilitation, the activity ratio of hamstrings and adductors to QF decreased slightly toward normal so there were no significant differences between the AL and controls. Impaired biarticular RF muscle function in stroke patients is the limiting factor during knee extension-flexion movements. After rehabilitation, improved functional performance was partly explained by the fact that the activities of the RF and vasti became more synchronized. VE-PC MRI can provide quantitative in vivo measurements of both superficial and deep muscles, and the information acquired after stroke can be utilized to render therapy more efficient and individually tailored.
Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA, 2013
Summary Inphase and out-of-phase magnetic resonance imaging is a robust and fast method which can... more Summary Inphase and out-of-phase magnetic resonance imaging is a robust and fast method which can provide similar vertebral bone marrow fat estimation as 1H proton magnetic resonance spectroscopy, indicating that this technique is a potentially useful tool in both research and clinical practice. Introduction The importance of evaluating bone marrow fat lies in the fact that osteoporosis and obesity, two disorders of body composition, are growing in prevalence. Bone fat mass can be reliably assessed using proton magnetic resonance spectroscopy (1H MRS), but this method is technically demanding and needs advanced post-processing unlike inphase and out-of-phase magnetic resonance imaging (MRI), which is a robust and fast method. Methods We compared vertebral bone marrow fat (BMF) content assessed by inphase and out-of-phase MRI and 1H MRS using a 1.5-T MRI scanner in mothers (n = 34, aged 49.4 years), fathers (n = 31, aged 53.1 years) and their daughters (n = 40, aged 20.3 years) who participated in the CALEX family study. Signal intensity on the inphase and out-of-phase MRI was analyzed from the same location and size of the single-voxel 1H MRS measurement. Results Positive correlations were found between 1H MRS and inphase and out-of-phase MRI in the axial plane (r = 0.746, p < 0.001) and sagittal plane (r = 0.804, p < 0.001). The mean differences between 1H MRS and inphase and out-of-phase MRI in the axial and sagittal planes were relatively small, at 4.13 and 2.67 %, and the agreement between techniques was 89.4 and 93.2 %, respectively. Girls had a significantly lower vertebral BMF than mothers and fathers with both methods (for all, p < 0.001). Conclusions We conclude that inphase and out-of-phase MRI can provide similar vertebral BMF estimation as 1H MRS, indicating that this technique is a potentially useful tool in both research and clinical practice.
Current methods of clinical assessment of muscle coordination and function after stroke do not pr... more Current methods of clinical assessment of muscle coordination and function after stroke do not provide information on deep muscles. The objective of this study was to examine how stroke affects both superficial and deep muscles&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; coordination and whether muscle function improves after rehabilitation. Muscle function, coordination, and activity of quadriceps femoris (QF) and hamstrings were evaluated in 10 stroke patients with mild hemiparesis and in 6 controls using velocity-encoded cine phase-contrast magnetic resonance imaging (VE-PC MRI), surface electromyography (sEMG), and maximal voluntary isometric contraction torque (MVC). At baseline, the peak muscle velocity of the rectus femoris (RF) and the ratio between the peak velocities of the RF and vasti were lower in the affected limb (AL) of stroke patients than in controls. Co-contraction of agonists and antagonists was higher in the AL than in controls. Muscle activity measured by sEMG showed similar behavior. After rehabilitation, the activity ratio of hamstrings and adductors to QF decreased slightly toward normal so there were no significant differences between the AL and controls. Impaired biarticular RF muscle function in stroke patients is the limiting factor during knee extension-flexion movements. After rehabilitation, improved functional performance was partly explained by the fact that the activities of the RF and vasti became more synchronized. VE-PC MRI can provide quantitative in vivo measurements of both superficial and deep muscles, and the information acquired after stroke can be utilized to render therapy more efficient and individually tailored.
Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA, 2013
Summary Inphase and out-of-phase magnetic resonance imaging is a robust and fast method which can... more Summary Inphase and out-of-phase magnetic resonance imaging is a robust and fast method which can provide similar vertebral bone marrow fat estimation as 1H proton magnetic resonance spectroscopy, indicating that this technique is a potentially useful tool in both research and clinical practice. Introduction The importance of evaluating bone marrow fat lies in the fact that osteoporosis and obesity, two disorders of body composition, are growing in prevalence. Bone fat mass can be reliably assessed using proton magnetic resonance spectroscopy (1H MRS), but this method is technically demanding and needs advanced post-processing unlike inphase and out-of-phase magnetic resonance imaging (MRI), which is a robust and fast method. Methods We compared vertebral bone marrow fat (BMF) content assessed by inphase and out-of-phase MRI and 1H MRS using a 1.5-T MRI scanner in mothers (n = 34, aged 49.4 years), fathers (n = 31, aged 53.1 years) and their daughters (n = 40, aged 20.3 years) who participated in the CALEX family study. Signal intensity on the inphase and out-of-phase MRI was analyzed from the same location and size of the single-voxel 1H MRS measurement. Results Positive correlations were found between 1H MRS and inphase and out-of-phase MRI in the axial plane (r = 0.746, p < 0.001) and sagittal plane (r = 0.804, p < 0.001). The mean differences between 1H MRS and inphase and out-of-phase MRI in the axial and sagittal planes were relatively small, at 4.13 and 2.67 %, and the agreement between techniques was 89.4 and 93.2 %, respectively. Girls had a significantly lower vertebral BMF than mothers and fathers with both methods (for all, p < 0.001). Conclusions We conclude that inphase and out-of-phase MRI can provide similar vertebral BMF estimation as 1H MRS, indicating that this technique is a potentially useful tool in both research and clinical practice.
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