Fig 4

Follow-up MR images of a 20-year-old professional football player with a history of partial tear of the proximal third of the musculotendinous junction of the rectus femoris muscle 3 weeks prior. The patient presented with a re-injury after resuming competitive activity. a Sagittal and (b) axial FS T2-w images and (c) axial T1-w image. Extending distally from the proximal musculotendinous junction, a multisegmental intratendinous partial tear of the rectus femoris is demonstrated with significant peritendinous muscle oedema (arrows). c Epifascial intramuscular hyperintensity on T1-w image in the anterior rectus femoris represents acute haemorrhage (arrow). At 5-month follow-up, (d) sagittal and (e) axial FS T2-w images show focal, full-thickness tendon disruption involving the deep tendon of the rectus femoris muscle (arrows). There is a musculotendinous gap, filled with fluid (arrow), at the level of the mid-thigh measuring 3.4 cm in length. The fluid collection represents liquefied residual haematoma with hyperintensity on the (e, arrow) FS T2-w TSE image and isointensity to hypointensity on the (f, arrow) T1-w image. Some of the fibres of the intramuscular tendon remain intact. g Axial FS T2-w image at 6.5-month follow-up demonstrates only very discrete peritendinous oedema adjacent to the tendon (arrow)