Variables | Evaluation | Category | MRI findings |
---|---|---|---|
Connective tissue tear (tendon, raphe, septa and aponeurosis) | Orientation of the disruption respect to the longitudinal axis of the tendon | Absent Transversal Longitudinal Mixed | Hyperintense gap on T2-weighted images with clear loss of connective tissue continuity |
Loss of tendon tension (wavy sign) | Location of irregularity of the tendon | Absent Present | Loss of longitudinal alignment in the tendon in the form of an undulating (wavy) pattern |
Muscle fibres tear | Presence of a measurable gap | Absent Present | Hyperintense gap on T2 with clear loss of muscle fibres continuity Isolated (between fibres) or in the myoconnective interface, and at this last level associated with gaps of connective tissue |
Loss of pennation angle | Anchorage of muscle fibres | Absent Present | Loss of anchorage of the muscular fibres with the connective tissue |
Oedema Intramuscular | High signal intensity within the muscle on fluid sensitive sequences | Adaptive (cotton-like pattern) Feathery oedema (dissecting the Interstitial space between muscle fibres) | Muscle area of low to intermediate signal intensity on T1-weighted images and high signal intensity on fluid sensitive sequences Feathery pattern: oedema that dissects the interstitial space between muscle fibres Cotton-like pattern: more diffuse and poorly defined without architectural muscle distortion |
Oedema Intermuscular | Intermuscular fluid on fluid sensitive sequences | Absent Present | Presence of fluid in the intermuscular space |
Improvement in oedema | Total or partial radiological regression of intramuscular and/or intermuscular oedema | Yes No | Decrease in the extent of the both forms of oedema in control MRI prior to RTP as compared with baseline MRI |
Scar tissue | Morphology of scar tissue | Hypertrophic Elongated Round Fusiform | Thickness greater than myoconnective environment (hypertrophic) The morphology of the callus is given by its thickening in the longitudinal plane (fusiform), in the axial plane (rounded) or uniform with respect to the intact tendon (elongated) |
Maturation of scar tissue | Immature Mature | A T2 hyperintense centre surrounded by a very thin hypointense peripheral line (immature), progressive filling in and losing signal Formation of hard callus with low signal in both T1- and T2-weighted images (mature) | |
Callus gap (disruption) | Absent Present | Persistence or appearance of hyperintense gap on T2-weigthed images with clear transversal loss of its continuity |