MR Imaging Diagnosis of Occult Bone and Cartilage Injuries

Objective To investigate MR imaging features of occult bone and cartilage injuries and to evaluate the relationship among bone contusion,occult fracture and joint cartilage injury.Methods 101 patients with occult bone and cartilage injuries were retrospectively analyzed,including 70 patients with bone contusion,13 with occult fracture and 18 with joint cartilage injury.MR imaging features,distribution of lesions and the sensitive series in the detection of bone contusion by MR imaging were evaluated.Results T1WI and STIR or PDWI(f/s) were more sensitive sequences in detecting the bone contusion(95.7% and 100% respectively).Bone contusion course of mainly distributed in the margin area of joint and in superior portion of vetebral body.The course of the occult fracture lines was irregular,the width of fracture lines was about 1.8 mm with bone contusion in nearby area.On MR imaging,joint cartilage injury appeared as the thicknees of articular cartilage decreased or defect,subcartilage contusion was seen in 100%.Conclusion The occult fracture and joint cartilage injuries are all associated with bone contusion.MR imaging is the sensitive method in determining the occult bone injuries.