Table 1.

Key MRI findings for the diagnosis of localized disorders of the fasciae

Diagnosis	Key MRI findings
Morel-Lavallée lesion	• Fusiform or ovoid fluid collection • Located at the interface between the hypodermic fat and the deep peripheral fascia
Myofascial and myotendinous injuries	• Loss of the normal organization of the muscles and fasciae with abnormal heterogenous intermediate signal intensity • Inconstant collections of fluid and/or blood • Located at the interface between the muscle and the epimysium (myofascial injuries) and the interface between the muscle and the tendon (myotendinous injuries)
Muscle hernia	• Focal bulging of the muscle tissue out of the muscle compartment into the hypodermic fat • Interruption of the deep peripheral fascia is inconstantly observed
Non-necrotizing and necrotizing cellulitis	• Infiltration of the hypodermis with fluid-signal intensity and enhancement after contrast material injection • May be associated with collections and lack of enhancement of the hypodermis due to poor vascularization and/or necrosis (necrotizing cellulitis)
Necrotizing fasciitis	• Thickening of the deep fasciae with high signal intensity on fluid-sensitive sequences and heterogeneous enhancement after contrast material injection • Low signal intensity areas visible on all sequences suggestive of gas (highly specific but not sensitive) • Extensive thickening of the intermuscular fasciae with an appearance suggesting incomplete vascularization supports the diagnosis
Palmar fibromatosis	• Nodules in continuity with the palmar aponeurosis • Diagnosis is usually clinical
Plantar fibromatosis	• Nodule in continuity with the plantar aponeurosis • May be multiple and bilateral