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Updated: May 13, 2026
Quantitative Magnetic Resonance Imaging of Skeletal Muscle Disease
Published on: December 18, 2016
Quantitative muscle ultrasound as a window into disease progression in infantile-onset Pompe disease
Neelam Makhijani1, Myriam Boueri1, Bijan Abar1
1Division of Medical Genetics, Department of Pediatrics, Duke University School of Medicine, Durham, NC, United States.
Insights
Quantitative muscle ultrasound (QMUS) shows promise for monitoring infantile-onset Pompe disease (IOPD) in patients undergoing enzyme replacement therapy (ERT). This noninvasive tool can track muscle health and treatment effectiveness.
Area of Science:
- Neurology
- Pediatrics
- Medical Imaging
Background:
- Infantile-onset Pompe disease (IOPD) results from acid alpha-glucosidase deficiency, leading to glycogen buildup and severe muscle weakness.
- Enzyme replacement therapy (ERT) has improved outcomes, but noninvasive monitoring tools are crucial.
- Quantitative muscle ultrasound (QMUS) offers a potential noninvasive method for assessing muscle involvement.
Purpose of the Study:
- To assess the effectiveness and feasibility of QMUS in monitoring muscle disease in IOPD patients on ERT.
- To correlate QMUS findings with clinical outcomes and disease severity.
Main Methods:
- Echo intensity (EI) was measured annually in seven muscle groups of eight IOPD patients receiving ERT.
- A composite EI Sum Score was calculated, with EI >50 units considered abnormal.
- QMUS data were compared with Gross Motor Function Measure (GMFM) scores.
Main Results:
- All patients exhibited abnormal EI in at least one muscle group.
- Upper extremity EI was significantly lower than lower extremity EI (p=0.002).
- Higher EI scores correlated with increased myopathy severity and wheelchair dependence, while lower scores indicated better motor function.
Conclusions:
- QMUS is a valuable noninvasive tool for evaluating muscle health in IOPD patients on ERT.
- This technique may assist in tracking disease progression and treatment efficacy.
- QMUS can complement existing monitoring methods for IOPD.
Background:
Infantile-onset Pompe disease (IOPD) is caused by a deficiency of the enzyme acid alfa glucosidase, resulting in glycogen accumulation in muscles and other tissues. Without treatment, affected infants typically die within two years. Enzyme replacement therapy (ERT) has significantly improved survival and functional outcomes, especially with early initiation, higher dosing, immune modulation, and newer therapeutic options. However, effective noninvasive tools to monitor disease progression and treatment response are still needed. Quantitative muscle ultrasound (QMUS) may serve as a useful alternative.
Objective:
To evaluate the effectiveness and feasibility of QMUS for monitoring muscle involvement in IOPD.
Methods:
This study assessed echo intensity (EI) measurements from QMUS in eight patients with IOPD receiving long-term ERT. EI was recorded annually in seven muscle groups. EI >50 units was considered abnormal, and a composite EI Sum Score was calculated. These values were compared with Gross Motor Function Measure (GMFM) scores using univariable regression.
Results:
Patients began ERT at a median age of 7 weeks. QMUS assessments were performed, with ages ranging from 7 months to 21 years (median age of 9.5 years) at first evaluation. All patients had at least one muscle group with abnormal EI. Upper extremity EI was significantly lower (mean 47.3) than lower extremity muscle groups (mean 64.1, p = 0.002). Higher EI scores correlated with more severe myopathy and wheelchair use, while lower scores reflected better motor outcomes.
Conclusions:
QMUS is a promising noninvasive tool for monitoring muscle health in patients with IOPD receiving ERT. It may aid in assessing disease progression and treatment efficacy.
