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Muscle velocity and inertial force from phase contrast MRI
Author(s) -
Wentland Andrew L.,
McWalter Emily J.,
Pal Saikat,
Delp Scott L.,
Gold Garry E.
Publication year - 2015
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.25013
Subject(s) - forearm , magnetic resonance imaging , voxel , acceleration , inertial frame of reference , physics , fictitious force , contrast (vision) , phase contrast microscopy , inertial measurement unit , wrist , biomedical engineering , nuclear medicine , mathematics , medicine , nuclear magnetic resonance , mechanics , computer science , anatomy , radiology , classical mechanics , artificial intelligence , optics
Purpose To evaluate velocity waveforms in muscle and to create a tool and algorithm for computing and analyzing muscle inertial forces derived from 2D phase contrast (PC) magnetic resonance imaging (MRI). Materials and Methods PC MRI was performed in the forearm of four healthy volunteers during 1 Hz cycles of wrist flexion‐extension as well as in the lower leg of six healthy volunteers during 1 Hz cycles of plantarflexion‐dorsiflexion. Inertial forces (F) were derived via the equation F = ma. The mass, m, was derived by multiplying voxel volume by voxel‐by‐voxel estimates of density via fat‐water separation techniques. Acceleration, a, was obtained via the derivative of the PC MRI velocity waveform. Results Mean velocities in the flexors of the forearm and lower leg were 1.94 ± 0.97 cm/s and 5.57 ± 2.72 cm/s, respectively, as averaged across all subjects; the inertial forces in the flexors of the forearm and lower leg were 1.9 × 10 −3 ± 1.3 × 10 −3 N and 1.1 × 10 −2 ± 6.1 × 10 −3 N, respectively, as averaged across all subjects. Conclusion PC MRI provided a promising means of computing muscle velocities and inertial forces—providing the first method for quantifying inertial forces. J. Magn. Reson. Imaging 2015;42:526–532.