Table 2.

Radiologic findings in Achilles tendon disorders

Term/Imaging	Plain radiography	Ultrasound	CT	MRI
Mid-portion Achilles tendinopathy	Deviation of soft tissue contours is usually present. In rare cases calcifications can be found	Tendon larger than normal in both cross-sectional area and antero-posterior diameter. Hypoechoic areas within the tendon, disruption of fibrillar pattern, increase in tendon vascularity (Echo-Doppler) mainly in ventral peritendinous area	In case (massive) calcification are seen on plain radiography. CT imaging can be helpful in pre-operative planning, showing the exact size and location of the calcifications.	Fat- saturated T1 or T2 images: fusiform expansion,central enhancement consistent with intratendinous neovascularization
Paratendinopathy
Acute	–	A normal Achilles tendon with circumferential hypoechogenic halo	–	Peripheral enhancement on fat-saturated T1 or on T2 images
Chronic		A thickened hypoechoic paratenon with poorly defined borders may show as a sign of peritendinous adhesions; increase in tendon vascularity (Echo-Doppler) mainly in ventral peritendinous area
Insertional Achilles tendinopathy	May show ossification or a bone spur at the tendon’s insertion; possibly deviation of soft tissue contours	Calcaneal bony abnormalities	Bone formation at insertion. CT scan is indicated mainly for pre-operative planning. It shows the exact location and size of the calcifications and spurs	Bone formation and/or on STIR (short tau inversion recovery) hyperintense signal at tendon insertion
Retrocalcaneal bursitis	A postero-superior calcaneal prominence can be identified; radio-opacity of the retrocalcaneal recess; possibly deviation of soft tissue contours	Fluid in the retrocalcaneal area/bursa (hyperechoic)	–	Hyperintense signal in retrocalcaneal recess on T2 weighed images
Superficial calcaneal bursitis	Possibly deviation of soft tissue contours	Fluid between skin and Achilles tendon	–	Hyperintense signal between Achilles tendon and subcutaneous tissue on T2 weighed images