Sensitive ultrasonic delineation of steroid treatment in living dystrophic mice with energy-based and entropy-based radio frequency signal processing

IEEE Trans Ultrason Ferroelectr Freq Control. 2007 Nov;54(11):2291-9. doi: 10.1109/tuffc.2007.533.


Duchenne muscular dystrophy is a severe wasting disease, involving replacement of necrotic muscle tissue by fibrous material and fatty infiltrates. One primary animal model of this human disease is the X chromosome-linked mdx strain of mice. The goals of the present work were to validate and quantify the capability of both energy and entropy metrics of radio-frequency ultrasonic backscatter to differentiate among normal, dystrophic, and steroid-treated skeletal muscle in the mdx model. Thirteen 12-month-old mice were blocked into three groups: 4 treated mdx-dystrophic that received daily subcutaneous steroid (prednisolone) treatment for 14 days, 4 positive-control mdx-dystrophic that received saline injections for 14 days, and 5 negative-control animals. Biceps muscle of each animal was imaged in vivo using a 40-MHz center frequency transducer in conjunction with a Vevo-660 ultrasound system. Radio-frequency data were acquired (1 GHz, 8 bits) corresponding to a sequence of transverse images, advancing the transducer from "shoulder" to "elbow" in 100-micron steps. Data were processed to generate both "integrated backscatter" (log energy), and "entropy" (information theoretic receiver, H(f)) representations. Analyses of the integrated-backscatter values delineated both treated-and untreated-mdx biceps from normal controls (p < 0.01). Complementary analyses of the entropy images differentiated the steroid-treated and positive-control mdx groups (p < 0.01). To our knowledge, this study represents the first reported use of quantitative ultrasonic characterization of skeletal muscle in mdx mice. Successful differentiation among dystrophic, steroid-treated, and normal tissues suggests the potential for local noninvasive monitoring of disease severity and therapeutic effects.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Algorithms
  • Animals
  • Anti-Inflammatory Agents / administration & dosage
  • Disease Models, Animal*
  • Image Enhancement / methods*
  • Image Interpretation, Computer-Assisted / methods
  • Mice
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Muscle, Skeletal / diagnostic imaging
  • Muscle, Skeletal / drug effects
  • Muscular Dystrophy, Duchenne / diagnostic imaging*
  • Muscular Dystrophy, Duchenne / drug therapy*
  • Prednisolone / administration & dosage*
  • Prognosis
  • Radio Waves
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Signal Processing, Computer-Assisted
  • Treatment Outcome
  • Ultrasonography / methods*


  • Anti-Inflammatory Agents
  • Prednisolone