Objective    To study the significance of MRI and to evaluate the effectiveness of X-ray film

CT

and MRI in the diagnosis of bone contusion.      Methods    Fifty-six cases of abnormal marrow signal in MRI but without fracture in knee in X-ray plain film were respectively analyzed.     Results    No obvious bone fracture sign was observed in X-ray film in all cases but bone contusion was found in MRI

which showed as high signal intensity on T

2

WI Short TI Inversion Recovery(STIR) and slightly low signal on T

1

WI.  Anterior and posterior cruciate ligament

medial and lateral collateral ligament

medial and lateral meniscus and synovium injuries were also fo

und in some cases of knee contusion.     Conclusion    Bone contusion could be detected in MRI in early stage. So if bone fracture was not found in X-ray plain film or CT

but ache and swelling in traumatic area is persistent

it is recommended to perform MRI examination.  STIR and Chem-sat series are sensitive in displaying slight bone marrow swelling

congestion

slender fracture of bone trabecula and are of great importance in diagnosing injuries in bone trauma.