MR Imaging of Meniscal Tears' Correlation with History of Trauma

PURPOSE: The medial meniscus is injured much more than the lateral meniscus. Because the medial meniscus is much larger in diameter, is thinner in its periphery and narrower in body than the lateral meniscus, and does not attach to either cruciate ligament. We evaluated correlations with sites of tear and history of trauma. METHODS AND MATERIALS: We reviewed retrospectively in 43 patients with meniscal tears on MRI(51 cases) and correlated them with history of trauma. RESULTS: The most common site of injury was the posterior horn of the medial meniscus(32/51), but high incidence of lateral meniscal tear compared with previous reports was seen. In the cases which had history of trauma, the posterior horn of medial meniscus was most commonly injured(26/34) and 5 meniscal tears were combined with meniscal tear in the other site. The tear in the anterior horn of the medial meniscus was seen only in a patient which had history of trauma and combined with meniscal tear in the other site. But in the meniscal tears without definite history of trauma, the incidence of meniscal tear was different from the meniscal tear with history of trauma. The incidence of lateral meniscal tear(11/17) was highter than medial meniscal tear and the posterior horn of lateral meniscus was commonly injured. CONCLUSION: We concluded that the medial meniscus was commonly injured, especially posterior horn, but in the cases which had no definite history of trauma, the lateral meniscus was commonly ipjured. An awareness of prevalent site of meniscal injuries may be helpful in the diagnostic interpretation of MR imaging of knee.

The changes of CT number in various organs according to hematocrite level

The computed tomography (CT) number is closely related to hematocrit level according to many of the previous reports. We measured the CT number in various organs, such as the frontal white matter, basal ganglia, occipital white matter, cerebrospinal fluid, liver, abdominal aorta, spleen, kidney, and psoas muscle. We correlated the CT numbers of the organs with hematocrit levels which were graded into 10% increments (20.0-29.9%, 30.0-39.9%, 40.0-49.9%). Thus the change of CT numbers in various organs according to the hematocrit level was analyzed. The increased CT numbers according to the 10% increment of hematocrit in the frontal white matter, basal ganglia, occipital white matter, liver, abdominal aorta, spleen, and psoas muscle were 1.3, 1.5, 1.6, 3.3, 5.3, 3.8, 2.4 respectively. Even though the CT numbers of the cerebrospinal fluid and kidney were not influenced by hematocrit level the CT numbers in most of the there organs postitively correlated with hematocrit level. Therefore, it was concluded that in the differential diagnosis using CT numbers, the hematocrit level of patient must be taken into consideration.