Diagnostic value of different related contrast material in dual-energy CT virtual noncalcium for detecting traumatic bone marrow edema in knee joint

Objective To evaluate the diagnostic value of related contrast material (Rel.CM) of the dual-energy CT (DECT) virtual noncalcium (VNCa) for detecting acute traumatic bone marrow edema in knee joint. Methods A total of 17 patients (18 knees) with definite trauma history and knee joint disorders were prospectively enrolled. Conventional CT, VNCa and MRI images were obtained by MRI and DECT scan. Each knee was divided into 12 regions, respectively, to observe the performance of MRI and VNCa images. The diagnostic efficacy of different Rel. CM values (1.25, 1.45, 1.75) was analyzed for the knee traumatic bone marrow edema, select the best Rel. CM value. And the CT values of bone marrow and bone marrow damage were measured on VNCa of the optimal Rel. CM parameters. Using ROC to evaluate the efficacy of VNCa in different Rel. CM values for diagnosing traumatic bone marrow edema, the difference of CT value between bone marrow lesion and bone marrow in normal region of bone marrow was obtained by using rank sum test. Results DECT and MRI were performed in 17 patients (18 knees). Eighteen knees were divided into 216 areas. MRI showed 94 areas of bone marrow edema, including 35 in distal portion of femur, 59 in proximal tibia. Rel.CM values of 1.25, 1.45, 1.75 of the VNCa map were used to diagnose traumatic bone marrow edema in the knee with the area under the ROC curve of 0.643, 0.871, 0.656, respectively. Rel.CM with 1.45 VNCa diagram was the most accurate. The CT values of the bone marrow edema region and the normal region were-64.3 (-20.6 to-90.8) HU,-93.4 (-70.5 to-120.7) HU, respectively, on the VNCa graph with the optimal Rel.CM parameters (1.45) (Z=-8.270, P<0.05). Conclusions The VNCa image with a Rel.CM value of 1.45 has a better diagnostic performance for traumatic bone marrow edema in knee joint. CT value measurement in VNCa image can be used for quantitative analysis of traumatic bone marrow edema. Key words: Tomography, X-ray computed; Knee joint; Bone marrow edema; Related contrast material