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Updated: Sep 4, 2025
Quantitative Magnetic Resonance Imaging of Skeletal Muscle Disease
Published on: December 18, 2016
Reference values for MRI-derived psoas and paraspinal muscles and macroscopic fat infiltrations in paraspinal muscles
Kacper Marunowski1, Dominik Świętoń1, Włodzimierz Bzyl2
1Department of Radiology, Medical University of Gdansk, Gdansk, Poland.
Insights
This study introduces MRI-derived reference values for pediatric muscle mass and fat infiltration, crucial for diagnosing sarcopenia (muscle loss) in children. These findings provide essential data for assessing muscle health and adverse outcomes in pediatric populations.
Area of Science:
- Pediatric Radiology
- Musculoskeletal Imaging
- Body Composition Analysis
Background:
- Sarcopenia, or skeletal muscle mass loss, is increasingly recognized as a significant factor impacting children's health outcomes.
- Magnetic Resonance Imaging (MRI) offers a safe and accurate method for measuring tissue compartments, commonly used in pediatric imaging.
- A critical gap exists in MRI-derived normative data for assessing pediatric sarcopenia.
Purpose of the Study:
- To establish reference values for total psoas muscle area (tPMA), total paraspinal muscle area (tPSMA), and total macroscopic fat infiltration of the paraspinal muscles (tMFI) in children.
- To provide crucial data for the clinical assessment of sarcopenia in pediatric patients.
- To develop age- and sex-specific percentile charts for muscle and fat measurements.
Main Methods:
- Retrospective analysis of abdominal and pelvic MRI scans from 465 healthy children aged 1-18 years (2010-2021).
- Exclusion of children with chronic diseases or surgical history.
- Measurement of tPMA, tPSMA, and tMFI at the L4/L5 disc level; construction of LMS percentile charts; assessment of inter-observer and intra-observer reproducibility.
Main Results:
- Continuous increases in tPMA and tPSMA observed across all age groups, with significant sex differences by age 18.
- Median tPMA at 18 years: 26.37 cm² (girls) and 40.43 cm² (boys); median tPSMA: 40.76 cm² (girls) and 56.66 cm² (boys).
- Mean tMFI was 5.0% (girls) and 3.5% (boys); excellent reproducibility for all measurements.
Conclusions:
- Novel, highly reproducible, sex-specific MRI reference values for tPMS, tPSMA, and tMFI in children (1-18 years) have been established.
- These reference values at the L4/L5 level can aid clinicians in diagnosing sarcopenia in pediatric populations.
- The data supports the use of MRI-derived measurements for assessing sarcopenia as a prognostic marker in children.
Background:
Sarcopenia, defined as loss of skeletal muscle mass, is a novel term associated with adverse outcomes in children. Magnetic Resonance Imaging (MRI) is a safe and precise technique for measuring tissue compartments and is commonly used in most routine paediatric imaging protocols. Currently, there is a lack of MRI-derived normative data which can help in determining the level of sarcopenia. This study aimed to introduce reference values of total psoas muscle area (tPMA), total paraspinal muscle area (tPSMA), and total macroscopic fat infiltrations of the PSMA (tMFI).
Methods:
In this retrospective study, the local database was searched for abdominal and pelvic region MRI studies of children aged from 1 to 18 years (mean age (standard deviation (SD)) of 9.8 (5.5) years) performed in the years 2010-2021. Children with chronic diseases and a history of surgical interventions were excluded from the analysis. Finally, a total of 465 healthy children (n = 233 girls, n = 232 boys) were enrolled in the study. The values of the tPMA, tPMSA, and tMFI were measured in square centimetres (cm2 ) at the level of the L4/L5 intervertebral disc as the sum of the left and right regions. Age-specific and sex-specific muscle, fat, and body mass index percentile charts were constructed using the LMS method. Inter-observer agreement and intra-observer reproducibility were assessed using the Bland-Altman plots.
Results:
Both tPMA and tPSMA showed continuous increases in size (in cm2 ) throughout all age groups. At the age of 18, the median tPMA areas reached 26.37 cm2 in girls and 40.43 cm2 in boys. Corresponding tPSMA values were higher, reaching the level of 40.76 cm2 in girls and 56.66 cm2 in boys. The mean value of tMFI within the paraspinal muscles was 5.0% (SD 3.65%) of their total area in girls and 3.5% (SD 2.25%) in boys with the actual difference between sexes up to 0.96 cm2 . Excellent intra-observer reproducibility and inter-observer agreement were noted. Actual mean differences for tPMA were at the level of 0.43 and 0.39 cm2 , respectively. Mean bias for tPSMA was 0.1 cm2 for inter-observer and 0.05 cm2 for intra-observer measurements.
Conclusions:
Our findings demonstrate novel and highly reproducible sex-specific MRI-derived reference values of tPMS, tPSMA, and tMFI at the level of the L4/L5 intervertebral disc for children from 1 to 18 years old, which may guide a clinician in the assessment of sarcopenia, a prognostic outcome marker in children.
