Table 2.

Majority of studies selected for review used a variant of one of the following three scoring systems

Score	Lamminen [79]	Mercuri et al. [59, 78]	Jungbluth et al. [62, 64]
0		Normal	Normal
1	Normal muscle signal intensity	Early moth-eaten appearance, with scattered small areas of increased density on T1 MRI	Mild with only traces of increased signal intensity
2	Slightly hyperintense, patchy intramuscular signal changes	A: Late moth-eaten appearance, with numerous discrete areas of increased density with beginning confluence, comprising less than 30% of the volume of the individual muscle B: Late moth-eaten appearance, with numerous discrete areas of increased density with beginning confluence, comprising 30–60% of the volume of the individual muscle	Moderate with increased signal in less than 50% of affected muscle
3	Markedly hyperintense, patchy but widespread intramuscular changes	Washed-out appearance, fuzzy appearance due to confluent areas of increased density with muscle still present at the periphery	Severe with increased signal intensity in more than 50% of affected muscle
4	Total, homogeneous hyperintense signal change in whole muscle, equaling the signal intensity of adjacent subcutaneous or paramuscular fat	End-stage appearance, muscle replaced by increased density connective tissue and fat with only rim of fascia and neurovascular structures distinguishable	Entire muscle replaced by abnormal signal