Alterations of the proton-T2 time in relaxed skeletal muscle induced by passive extremity flexions. Rump, J.; Braun, J.R.; Papazoglou, S.; Taupitz, M.; and Sack, I. J Magn Reson Imaging, 23(4):541--546, Apr, 2006.
Alterations of the proton-T2 time in relaxed skeletal muscle induced by passive extremity flexions. [link]Paper  doi  abstract   bibtex   
To demonstrate reciprocal changes of the apparent proton-T2 time in the biceps and triceps due to passive contraction and extension of the muscle fibers.The contraction state of the upper arm muscles of six healthy volunteers was passively changed by alternating the forearm position between the straight-arm position and an elbow flexion of 90 degrees. The relaxation of the muscle during passive contraction and extension was measured with the use of muscle electromyography (EMG) experiments. Spin-echo (SE) MRI with increasing echo times (TEs) of 12-90 msec was used to acquire the averaged signal decay of the segmented biceps and triceps. The apparent T2 was deduced using monoexponential least-square fitting.The median T2 alterations in biceps and triceps among all volunteers were found to be 1.2 and -1.3 msec in the straight and bent forearm positions, respectively. The confidence intervals (0.5 to 1.7 msec in biceps, and -2.6 to -1.1 msec in triceps) clearly indicate that proton-T2 in MR images is significantly (P < 0.05) prolonged with muscle contraction.The observed increase of the proton-T2 time was correlated with a passive contraction of skeletal muscle fibers. This passive effect can be attributed to changes in the intracellular water mobility corresponding to the well-known "active" T2 increase that occurs after stimulation of muscle.
@article{ Rump2006,
  author = {Rump, Jens and Braun, J�rgen and Papazoglou, Sebastian and Taupitz,
	Matthias and Sack, Ingolf},
  title = {Alterations of the proton-T2 time in relaxed skeletal muscle induced
	by passive extremity flexions.},
  journal = {J Magn Reson Imaging},
  year = {2006},
  volume = {23},
  pages = {541--546},
  number = {4},
  month = {Apr},
  abstract = {To demonstrate reciprocal changes of the apparent proton-T2 time in
	the biceps and triceps due to passive contraction and extension of
	the muscle fibers.The contraction state of the upper arm muscles
	of six healthy volunteers was passively changed by alternating the
	forearm position between the straight-arm position and an elbow flexion
	of 90 degrees. The relaxation of the muscle during passive contraction
	and extension was measured with the use of muscle electromyography
	(EMG) experiments. Spin-echo (SE) MRI with increasing echo times
	(TEs) of 12-90 msec was used to acquire the averaged signal decay
	of the segmented biceps and triceps. The apparent T2 was deduced
	using monoexponential least-square fitting.The median T2 alterations
	in biceps and triceps among all volunteers were found to be 1.2 and
	-1.3 msec in the straight and bent forearm positions, respectively.
	The confidence intervals (0.5 to 1.7 msec in biceps, and -2.6 to
	-1.1 msec in triceps) clearly indicate that proton-T2 in MR images
	is significantly (P < 0.05) prolonged with muscle contraction.The
	observed increase of the proton-T2 time was correlated with a passive
	contraction of skeletal muscle fibers. This passive effect can be
	attributed to changes in the intracellular water mobility corresponding
	to the well-known "active" T2 increase that occurs after stimulation
	of muscle.},
  doi = {10.1002/jmri.20534},
  institution = {Institute of Radiology, Charit�-University Medicine Berlin, Berlin,
	Germany.},
  keywords = {Humans; Image Processing, Computer-Assisted; Isometric Contraction;
	Magnetic Resonance Imaging, methods; Muscle Contraction, physiology;
	Muscle, Skeletal, physiology; Prone Position; Protons; Statistics,
	Nonparametric; Upper Extremity, physiology},
  language = {eng},
  medline-pst = {ppublish},
  owner = {Heiko},
  pmid = {16514596},
  timestamp = {2013.07.26},
  url = {http://dx.doi.org/10.1002/jmri.20534}
}
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