Acute and Chronic Tears of Anterior Cruciate Ligament: Role of Gadolinium-enhanced MR Imaging

ABSTRACT

PURPOSE: To evaluate the efficacy of fat-suppressed gadolinium-enhanced MR imaging in differentiating acutefrom chronic ligament tears of anterior cruciate ligament. MATERIALS AND METHODS: MR images of 22 patients witharthroscopically proven complete tear of the anterior cruciate ligament were retrospectively reviewed. Theinterval between injury and MR examination was one day to seven years. When ligament tear was detected on MR imagewithe three months of injury, the case was considered acute;if detected after three months had elapsed, it wasjudged to be chronic. The extent of contrast enhancement was graded as 1, 2 or 3; grade 1, enhancement wasconfined to the expected ligament region; grade 2, enhancement extended to the joint capsule; grade 3, enhancementextended beyond the joint capsule. The grades of contrast enhancement correlated with the acute and chronic stagesof ligament tears. Associated bone bruise and/or adjacent soft tissue edema were also evaluated. RESULT: Among15 patients with acute ligament tear, nine (60%) showed grade 3 enhancement; among seven in whom tearing waschronic, four (57%) showed grade 1 enhancement. Bone bruising was present in 100% of acute tears (15/15) and 29%of chronic tears (2/7). Soft tissue edema was associated in 87% of acute tears (13/15) and 29% of chronic tears(2/7). CONCLUSION: Fat-suppressed gadolinium-enhanced MR imaging could help differentiate acute from chronictears of anterior cruciate ligament, as well as bone bruising and tissue edema.