Triggered intravoxel incoherent motion MRI for the assessment of calf muscle perfusion during isometric intermittent exercise

Abstract

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 ). 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.

A novel bayesian approach with conditional autoregressive specification for intravoxel incoherent motion diffusion‐weighted MRI

“…The maps of fD * (i.e., the product f × D * ) are also represented in these figures, as such parameter shows a linear correlation with blood flow. 36,37 The estimated D maps were qualitatively acceptable for each method, except for the LSQ approaches at low SNR, which showed noisy images. The three Bayesian methods presented more homogeneous f maps with respect to the LSQ, even at low SNR.…”

Demonstration of asymmetric muscle perfusion of the back after exercise in patients with adolescent idiopathic scoliosis using intravoxel incoherent motion (IVIM) MRI

“…An increase in f following exercise compared with baseline could be observed for up to 10 min in the masticator muscle and even up to 20 min in the forearm and the thigh . In another study, IVIM parameters reverted to resting values within 3 min in the calf . These differences might be due to different exercise intensities.…”

“…Of the eight patients with AIS (all females; mean ± standard deviation [range] 32 ± 12 [17‐47] years old), seven exhibited a standard thoracic right, lumbar left convex scoliosis with a thoracic Cobb angle of 35° ± 10° [25°‐47°] and a lumbar Cobb angle of 28° ± 10° [15°‐41°], and one exhibited an atypical right convex lumbar scoliosis with a Cobb angle of 30° (Table ). The control group was made up of nine healthy volunteers (seven females and two males; 25 ± 1 years old). All patients and volunteers successfully performed the Roman chair exercise, and exhaustion was reached after 1 min 15 s ± 21 s [48 s‐1 min 40 s] in the AIS patients, and after 1 min 37 s ± 22 s [1 min 5 s‐2 min 3 s] in the healthy volunteers ( p < 0.05).…”

“…26 In another study, IVIM parameters reverted to resting values within 3 min in the calf. 27 These differences might be due to different exercise intensities. Further, and interestingly, Nguyen et al 21 found similar fD* values after Jobe and lift-off tests independently of the order in which these tests were consecutively performed, suggesting that local muscle reperfusion might readjust dynamically to the current conditions.…”

“…[14][15][16][17] Perfusion imaging is thought to be the best technique for accurately assessing muscle energy consumption, 18 and could therefore be used to study non-invasively muscular activation patterns. Intravoxel incoherent motion (IVIM) is a magnetic resonance perfusion imaging technique that extracts local perfusion information from a multi-b-value diffusion-weighted sequence, 19 and can be used for quantitative muscular perfusion imaging, [20][21][22][23][24][25][26][27][28] with a high resolution and large field of view compared with methods such as electromyography or ultrasound, permitting a detailed analysis of the muscular perfusion pattern. A Roman chair is a piece of equipment to exercise back flexion and extension and induces suitably well localized muscle activation.…”