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

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.

Correlation between Osteoporosis and Skin Thickness on CT Scan

PURPOSE: The purpose of this study was to evaluate the relationship between osteoporosis and skin thicknessas shown by CT scanning. MATERIALS AND METHODS: Eighty- six women with osteoporosis (mean age, 52) and 51 normalcontrols (mean age, 50) participated in the study. For a quantitative CT examinations, a CT scanner(Somatom Plus,Siemens) was used. Osteoporosis was defined as present when spinal bone mineral density was more than 2.5 standarddeviations below young normal density, as determined by quantitative CT. Patients with endocrinologic, malignantor collagen disease and undergoing antimetabolite or steroid therapy were excluded. The thickness of back skin wasretrospectively measured at the third lumbar vertebra level, as seen on CT films, using a conventional magnifier.For statistical analysis, Students' t test and Spearman's rank correlation were used. RESULTS: On the basis of CTscans, the mean thickness of back skin in the osteoporotic group(0.50+/-0.20 mm) was significantly less than innormal control subjects(0.80+/-0.23 mm) (p<0.001). Significant correlation was observed between skin thickness andbone mineral density(r=0.523, p<0.0001). Sensitivity, specificity, accuracy, and positive and negative predictivevalues were measured as 76, 78, 76, 88, 62% with a cut-off value of 0.6 and 84, 61, 77, 81, 66% with a cut-offvalue of 0.7, respectively. CONCLUSION: The present study demonstrated that the thickness of back skin, asmeasured by CT scanning, is predictive of osteoporosis.