A comparison of multidetector CT versus radiography for ankle fracture detection demonstrated only 87% and 78% sensitivity, respectively, for calcaneal fracture and talar fractures by radiography as compared with CT [48]. Occult osteochondral fractures of the subtalar joint may only be visualized on CT, particularly in patients without Acute Trauma to the Ankle dislocation, with fractures involving the posterior facet, with associated massive swelling, or with failure to regain subtalar motion after a period of immobilization [49]. CT with IV contrast is not indicated in this scenario because soft-tissue abnormalities and fluid collections can be identified on noncontrast high-resolution CT studies. MRI Ankle MRI of the ankle without IV contrast is most sensitive for evaluation of occult fractures with associated bone marrow edema patterns, particularly in inversion injuries and persistent lateral ankle pain, as well as presence and extent of soft-tissue injuries [29]. Stress injuries of bone, including those of the weekend warrior, are best depicted by MRI [50]. MRI is the reference standard for ligamentous injury and assessment of stability, which is particularly important in athletes, in whom determination of grade (1, 2, or 3) of syndesmotic ligament, anterior tibiofibular ligament, and deltoid injuries is critical for treatment planning and return to sport assessment [51]. High-resolution evaluation of the tendons and ligaments allows distinction between tendinopathy, sprain, and partial or complete tears. Ligament and tendon injuries can occur without fracture on radiography. Grossterlinden et al [52] compared MRI and radiography and showed that 15% of ligamentous injuries (including sprains, partial tears, and complete tears) at the syndesmosis in acute ankle injuries on MRI demonstrated no fracture on radiography.
Acute Trauma to the Ankle. A comparison of multidetector CT versus radiography for ankle fracture detection demonstrated only 87% and 78% sensitivity, respectively, for calcaneal fracture and talar fractures by radiography as compared with CT [48]. Occult osteochondral fractures of the subtalar joint may only be visualized on CT, particularly in patients without Acute Trauma to the Ankle dislocation, with fractures involving the posterior facet, with associated massive swelling, or with failure to regain subtalar motion after a period of immobilization [49]. CT with IV contrast is not indicated in this scenario because soft-tissue abnormalities and fluid collections can be identified on noncontrast high-resolution CT studies. MRI Ankle MRI of the ankle without IV contrast is most sensitive for evaluation of occult fractures with associated bone marrow edema patterns, particularly in inversion injuries and persistent lateral ankle pain, as well as presence and extent of soft-tissue injuries [29]. Stress injuries of bone, including those of the weekend warrior, are best depicted by MRI [50]. MRI is the reference standard for ligamentous injury and assessment of stability, which is particularly important in athletes, in whom determination of grade (1, 2, or 3) of syndesmotic ligament, anterior tibiofibular ligament, and deltoid injuries is critical for treatment planning and return to sport assessment [51]. High-resolution evaluation of the tendons and ligaments allows distinction between tendinopathy, sprain, and partial or complete tears. Ligament and tendon injuries can occur without fracture on radiography. Grossterlinden et al [52] compared MRI and radiography and showed that 15% of ligamentous injuries (including sprains, partial tears, and complete tears) at the syndesmosis in acute ankle injuries on MRI demonstrated no fracture on radiography.