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Noble J.J.,Kings College London | Noble J.J.,One Small Step Gait Laboratory | Keevil S.F.,Kings College London | Keevil S.F.,Rayne Institute | And 3 more authors.
British Journal of Radiology | Year: 2014

Objective: To compare Dixon-based MRI techniques for intramuscular fat quantification at 3 T with MR spectroscopy (MRS) in vitro and in vivo.Methods: In vitro, two- three- and four-point mDixon (Philips Medical Systems, Best, Netherlands) sequences with 10°, 20° and 30° flip angles were acquired fromseven test phantoms with sunflower oil-water percentages of 0-60% sunflower oil and calculated fat-water ratios compared with MRS. In vivo, two- three- and four-pointmDixon sequences with 10° flip angle were acquired and compared with MRS in the vastus medialis of nine healthy volunteers (aged 30.6±5.3 years; body mass index 22.2±2.6).Results: In vitro, all mDixon sequences correlated significantly with MRS (r>0.97, p<0.002). The measured phantom percentage fat depended significantly on the flip angle (p≤0.001) and mDixon sequence (p=0.005). Flip angle was the dominant factor influencing agreement with MRS. Increasing the flip angle significantly increased the overestimation of the mDixon sequences compared with MRS. In vivo, a significant difference was observed between sequences (p<0.001), with all mDixon sequences overestimating the intramuscular fat content of the vastus medialis muscle compared with MRS. Two-point mDixon agreed best with MRS and had comparable variability with the other mDixon sequences.Conclusion: This study demonstrates that mDixon techniques have good linearity and low variability for use in intramuscular fat quantification. To avoid significant fat overestimation with short repetition time, a low flip angle should be used to reduce T1 effects.Advances in knowledge: This is the first study investigating the optimal mDixon parameters for intramuscular fat quantification compared with MRS in vivo and in vitro. © 2014 The Authors.

Noble J.J.,Kings College London | Fry N.R.,One Small Step Gait Laboratory | Lewis A.P.,Kings College London | Keevil S.F.,The Rayne Institute | And 2 more authors.
Brain and Development | Year: 2014

Aim: Muscle weakness is a feature of individuals with spastic cerebral palsy (SCP) but there are few reports in the literature of muscle volume in this group. This study compares muscle volumes in adolescents and young adults with SCP with those of their typically developing (TD) peers. Design: Measurements of the volumes of nine major lower limb muscles in 19 independently ambulant subjects with SCP (mean age 14.2. years (sd 2.7), 11 male, GMFCS I (n= 5); GMFCS II (n= 14)), 19 TD subjects (mean age 16.5. years (sd 3.0), 11 male) were made using magnetic resonance imaging. Results: Lower limb muscles were smaller in the SCP group (p≤. 0.023 in all muscles) than the TD group with the exception of the vastii (lateralis. +. intermedius; p= 0.868) and gluteus maximus (p= 0.056). Average muscle volume deficit was 27.9%. Muscle volume deficits were significantly greater for distal muscles than proximal muscles (p<. 0.001). Conclusions: Reduced muscle size in adolescence and the natural history of sarcopenia in adulthood may contribute to the early loss of mobility of adults with SCP. © 2013 The Japanese Society of Child Neurology.

Noble J.J.,Kings College London | Noble J.J.,One Small Step Gait Laboratory | Charles-Edwards G.D.,Rayne Institute | Keevil S.F.,Rayne Institute | And 4 more authors.
BMC Musculoskeletal Disorders | Year: 2014

Background: It is known that individuals with bilateral spastic cerebral palsy (BSCP) have small and weak muscles. However, no studies to date have investigated intramuscular fat infiltration in this group. The objective of this study is to determine whether adults with BSCP have greater adiposity in and around their skeletal muscles than their typically developing (TD) peers as this may have significant functional and cardio-metabolic implications for this patient group. Methods. 10 young adults with BSCP (7 male, mean age 22.5 years, Gross Motor Function Classification System (GMFCS) levels I-III), and 10 TD young adults (6 male, mean age 22.8 years) took part in this study. 11 cm sections of the left leg of all subjects were imaged using multi-echo gradient echo chemical shift imaging (mDixon). Percentage intermuscular fat (IMAT), intramuscular fat (IntraMF) and a subcutaneous fat to muscle volume ratio (SF/M) were calculated. Results: IntraMF was higher with BSCP for all muscles (p = 0.001-0.013) and was significantly different between GMFCS levels (p < 0.001), with GMFCS level III having the highest IntraMF content. IMAT was also higher with BSCP p < 0.001). No significant difference was observed in SF/M between groups. Conclusion: Young adults with BSCP have increased intermuscular and intramuscular fat compared to their TD peers. The relationship between these findings and potential cardio-metabolic and functional sequelae are yet to be investigated. © 2014 Noble et al.; licensee BioMed Central Ltd.

Noble J.J.,Kings College London | Noble J.J.,One Small Step Gait Laboratory | Fry N.,One Small Step Gait Laboratory | Lewis A.P.,Kings College London | And 5 more authors.
Bone | Year: 2014

Objective: The aim of this study is to investigate how bone strength in the distal femur and proximal tibia are related to local muscle volume in ambulant individuals with bilateral spastic cerebral palsy (CP). Methods: Twenty-seven participants with CP (mean age: 14.6 ± 2.9. years; Gross Motor Function Classification System (GMFCS) levels I-III) and twenty-two typically developing (TD) peers (mean age: 16.7 ± 3.3. years) took part in this study. Periosteal and medullary diameter in the distal femur and cortical bone cross-sectional area (CSA) and thickness (CT) in the distal femur and proximal tibia were measured along with nine lower limb muscle volumes using MRI. Additionally, the polar section modulus (Zp) and buckling ratio (BR) were calculated to estimate bone bending strength and compressional bone stability respectively in the distal femur. The relationships of all measured parameters with muscle volume, height, age, body mass, gender, and subject group were investigated using a generalized linear model (GZLM). Results: In the distal femur, Zp was significantly positively related to thigh muscle volume (p= 0.007), and height (p= 0.026) but not significantly related to subject group (p= 0.076) or body mass (p= 0.098). BR was not significantly different between groups and was not related to any of the variables tested. Cortical bone CSA was significantly lower in the CP group at both the distal femur (p= 0.002) and proximal tibia (p= 0.009). It was also positively associated with thigh muscle volume (p<. 0.001) at the distal femur, and with subject height (p= 0.005) at the proximal tibia. Conclusions: Bending and compressional strength of the femur, estimated from Zp and cortical bone CSA respectively, is associated with reduced thigh muscle volume. Increasing muscle volume by strength training may have a positive effect on bone mechanics in individuals with CP. © 2014 Elsevier Inc.

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