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Triggered intravoxel incoherent motion MRI for the assessment of calf muscle perfusion during isometric intermittent exercise
Author(s) -
Mastropietro Alfonso,
Porcelli Simone,
Cadioli Marcello,
Rasica Letizia,
Scalco Elisa,
Gerevini Simonetta,
Marzorati Mauro,
Rizzo Giovanna
Publication year - 2018
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/nbm.3922
Subject(s) - intravoxel incoherent motion , isometric exercise , perfusion , plantar flexion , diffusion mri , medicine , nuclear medicine , magnetic resonance imaging , anatomy , cardiology , radiology , ankle
The main aim of this paper was to propose triggered intravoxel incoherent motion (IVIM) imaging sequences for the evaluation of perfusion changes in calf muscles before, during and after isometric intermittent exercise. Twelve healthy volunteers were involved in the study. The subjects were asked to perform intermittent isometric plantar flexions inside the MRI bore. MRI of the calf muscles was performed on a 3.0 T scanner and diffusion‐weighted (DW) images were obtained using eight different b values (0 to 500 s/mm 2 ). Acquisitions were performed at rest, during exercise and in the subsequent recovery phase. A motion‐triggered echo‐planar imaging DW sequence was implemented to avoid movement artifacts. Image quality was evaluated using the average edge strength (AES) as a quantitative metric to assess the motion artifact effect. IVIM parameters (diffusion D , perfusion fraction f and pseudo‐diffusion D *) were estimated using a segmented fitting approach and evaluated in gastrocnemius and soleus muscles. No differences were observed in quality of IVIM images between resting state and triggered exercise, whereas the non‐triggered images acquired during exercise had a significantly lower value of AES (reduction of more than 20%). The isometric intermittent plantar‐flexion exercise induced an increase of all IVIM parameters ( D by 10%; f by 90%; D * by 124%; fD * by 260%), in agreement with the increased muscle perfusion occurring during exercise. Finally, IVIM parameters reverted to the resting values within 3 min during the recovery phase. In conclusion, the IVIM approach, if properly adapted using motion‐triggered sequences, seems to be a promising method to investigate muscle perfusion during isometric exercise.