Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
Muscle Denervation
KEY FACTS
Terminology
-
Secondary muscle injury resulting from denervation following nerve injury
Imaging
-
Acute denervation
-
Muscle appears normal on T1WI
-
Diffusely increased signal intensity on T2WI, STIR
-
Mild, homogeneous enhancement with gadolinium
-
-
Chronic denervation
-
Fatty atrophy evident on T1WI
-
Muscle volume decreased
-
Denervation edema often persists for prolonged period
-
Top Differential Diagnoses
-
Disuse atrophy
-
Muscle trauma
-
Muscle inflammation or infection
-
Radiation myopathy
Pathology
-
Nerve tumor, infection, autoimmune neuritis, peripheral neuropathy or injury
Clinical Issues
-
Weakness, muscle volume loss in distribution of injured nerve
-
May be painful
-
-
Acute denervation may partially or totally recover depending on nerve injury severity
-
Chronic denervation changes permanent
Diagnostic Checklist
-
Distribution of muscle signal abnormalities indicates location of nerve lesion
-
Obtain fluid-sensitive sequence that shows muscle of concern in cross section
Coronal STIR MR shows denervation edema
of the trapezius, which is innervated by the spinal accessory nerve. This nerve can be traumatized by carrying heavy loads on the shoulder.
of the trapezius, which is innervated by the spinal accessory nerve. This nerve can be traumatized by carrying heavy loads on the shoulder.
Coronal T1WI C+ FS MR in the same patient shows uniform enhancement
of the affected muscle. Muscle tears, in contrast, had a heterogeneous appearance.
of the affected muscle. Muscle tears, in contrast, had a heterogeneous appearance.
Axial T2WI FS MR shows a free muscle flap
to the leg. The muscle shows severe, diffuse edema with a few streaks of fat interspersed. This is an expected finding and should not be confused with infection.
to the leg. The muscle shows severe, diffuse edema with a few streaks of fat interspersed. This is an expected finding and should not be confused with infection.
Coronal T2WI FS MR shows denervation edema
throughout the intrinsic muscles of the foot. Denervation edema due to diabetes primarily involves the feet. It tends to be streakier and less homogeneous than denervation from other causes.
throughout the intrinsic muscles of the foot. Denervation edema due to diabetes primarily involves the feet. It tends to be streakier and less homogeneous than denervation from other causes.
TERMINOLOGY
Definitions
-
Secondary muscle injury resulting from denervation following nerve injury
IMAGING
You're Reading a Preview
Become a Clinical Tree membership for Full access and enjoy Unlimited articles
If you are a member. Log in here