Measurement of intramuscular fat by muscle echo intensity

Abstract

Purpose To compare ultrasound echo intensity (EI) to high-resolution T1-weighted MRI and to establish calibration equations to estimate percent intramuscular fat from EI. Methods Thirty-one participants underwent both ultrasound and MRI testing of 4 muscles: rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), and medial gastrocnemius (MG). Results Strong correlations were found between MRI percent fat and muscle EI after correcting for subcutaneous fat thickness (r = 0.91 in RF, r = 0.80 in BF, r = 0.80 in TA, r = 0.76 in MG). Three types of calibration equations were established. Conclusion Muscle ultrasound is a practical and reproducible method that can be used as an imaging technique for examination of percent intramuscular fat. Future ultrasound studies are needed to establish equations for other muscle groups to enhance its use in both research and clinical settings.

Scanning plane comparison of ultrasound‐derived morphological characteristics of the vastus lateralis

“…In SLI, the length of the fascia or connective tissue can be visualized throughout the entire thickness of the muscle. Previous research has shown that EI differs between distal and proximal locations within an individual muscle and that EI is dependent on scanning location (Young et al, 2015). In contrast, PTI produced a US image with a speckled appearance (Pillen and van Alfen, 2011).…”

“…Subcutaneous adipose tissue thickness is defined as the distance between the inferior border of the epithelium and the superior border of the superficial aponeurosis (Young et al, 2015). Intraclass correlations using model (3,1), SEM, MD, and CV between MT PTI taken on two separate days were determined to be: ICC 3,1 5 0.914; SEM 5 0.083 cm; MD 5 0.230 cm; CV 5 2.905%.…”

“…Miljkovic and Zmuda (2010) suggested that an increased amount of SubQ may actually infiltrate the muscle and increase EI values. Some researchers have demonstrated that EI values are positively correlated with SubQ (Nijboer-Oosterveld et al, 2011;Watanabe et al, 2013;Caresio et al, 2015;Young et al, 2015), whereas other researchers found no such correlation (Scholten et al, 2002;Wu et al, 2011;Fukumoto et al, 2012;Melvin et al, 2014). However, examination of the relationship between SubQ and EI has exhibited conflicting results.…”

Early resistance training-induced increases in muscle cross-sectional area are concomitant with edema-induced muscle swelling

“…Both US echo and magnetic resonance imaging (MRI) (e.g., changes in T2 signal) can show alterations in muscle tissue such as muscle edema, fibrous or fatty infiltration and muscle damage (Pillen and van Alfen 2011;May et al 2000;Nosaka and Clarkson 1996;Nosaka and Sakamoto 2001;Young et al 2015). The low cost, versatility and accessibility of ultrasound equipment (compared with a more expensive and sophisticated imaging technologies, e.g., MRI) makes this methodology a valuable option for assessing skeletal muscle.…”

Multiorgan, Multimodality Imaging in Cardiometabolic Disease

“…Ectopic intramuscular fat can be quantified non-invasively by ultrasound, computed tomography (CT) or MR. Ultrasound techniques may also identify differences in echogenicity between fat and lean muscle tissue 15 . However, intramuscular fat and connective tissue have similar echogeneic properties, a significant limitation of this technique 16 .…”