The X-ray and MRI diagnosis of osteochondritis dissecans in the knee joint / 中华放射学杂志

ABSTRACT

Objective To investigate the X-ray and MRI manifestations of osteochondritis dissecans (OCD) and to compare the sensitivity of detection among different sequences. Methods Thirty-six OCD cases (thirty-eight knees) with complete data were selected and analyzed. The sagittal and coronal images were acquired on T 1WI, T 2WI, PDWI, and FLASH T * 2WI. MRI manifestations were analyzed retrospectively with double blind contrast method. The radiographies were obtained on the same day. The sensitivity of detection among different sequences was also compared. Results (1) The medial femoral condyle was the most commonly affected location in the knee (63.2%). The proportion of classical type, expanded type, and inferocentral type was 55.3%, 15.8%, and 28.9%, respectively. (2) On radiographs, the lesions typically appeared as a well circumscribed area of sclerotic subchondral bone separated from the remainder of the epiphysis by a radiolucent line. (3) Subchondral bone lesion was displayed as small and crescent-shaped ( n =38) on the sagittal image and as wedge (14) or short bar (24) shape on coronal image. The signal of the lesion was hypointense or isointense on T 1WI,surrounded by a hypointense or hyperintense (FLASH T * 2WI, T 2WI) line. The subchondral plate disappeared or became thinner. Interruption or disappearance of the hyaline cartilage could be seen sometimes. (4) The detection rate on T 1WI was higher than that of PDWI, T 2WI, and FLASH T * 2WI. Conclusion (1) Osteochondritis dissecans has specific X-ray and MRI manifestations. The abnormality of the hyaline cartilage and the subchondral bone can be displayed by MRI. Thus a proper diagnosis can be made. (2) The detection rate on T 1WI is higher than that of PDWI, T 2WI, and FLASH T  2WI.