Objective To explore the MR imaging of reverse and separation of meniscal articular capsule.Methods MR imaging of reverse and separation of meniscus articular capsule confirmed by surgery and arthroscope were analyzed retrospectively in 8 cases.Results The “Butterfly knot sign” disappeared and was replaced with fluid signal on the sagittal slice of meniscal body in 8 cases. Part of back angle remained in 3 cases. “Double anterior cruciate ligament sign” was showed on one side of middle sagittal slice in 7 cases. “Reverse meniscus sign” was revealed in intercondylar fossa on the coronary view in ~8 cases. Abnormal high signal was showed in the injured meniscus in 6 cases. Abnormal high signal was detected in the opposite meniscus in 5 cases.Conclusion The MR findings of reverse and separation of meniscus articular capsule include disappearance of “butterfly knot sign”, appearance of “reverse meniscus sign” and “double anterior cruciate ligament sign”. The diagnosis would be established if the former 2 signs were present or all the 3 signs were present simultaneously.

Objective To analyze the imaging features and its value in diagnosing primary malignant fibrous histiocytoma(MFH) of bone.Methods Imaging features(X-ray,CT,MRI) in 8 cases of MFH confirmed pathologically,and were retrospectively reviewed.Results The location of lesions in 6 cases was in upper femur,2 cases was in upper tibilar.Worm-eaten-like bone destruction withindistinct margin was presented on X-ray film,some lesions showed slightly marginal sclerosis.Tumors were soft tissue density on CT(CT value was 34~35 HU).The masses of soft tissue were showed much distinct.Conclusion The primary MFH of bone is not of characteristic imaging findings.It can improve obviously the diagnosis of the disease by the comprehensive analysis of the imaging data.

Objective To explore MRI findings of intervertebral suppurative spondylitis. Methods MRI findings of intervertebral suppurative spondylitis in 12 cases proved by surgery and 6 cases defined by clinical features were retrospectively analyzed. The MRI protocol included un-enhanced conventional scan in 18 cases and contrast-enhanced scan in 11 cases. Results Of the 18 cases, single focus was found in 16 cases, and multiple loci were seen in 2 cases. MRI findings included (1) Disappearance sign of nuclear crevice in 17 cases, accumulated fluid sign of intervertebral disc in 15 cases, intervertebral disc perforation in 4 cases, and intervertebral space narrowing in 7 cases. (2) Bone destruction under end plate and marrow oedema were shown in 18 cases, 17 cases had end plate destruction, 16 cases had covered sign of end plate.(3) Paraspinal soft tissue swelling was shown in 18 cases, in which thick wall microabscess was formed in 4 cases. (4) Vertebral canal was involved in 12 cases, vertebral canal abscess was formed in 5 cases.(5) Lump enhancement was demonstrated in 4 cases, nodular enhancement in 2, and ring-like enhancement in 2, respectively. No enhancement was seen in 3 cases. Dural sac linear enhancement was shown in 6 cases, and patchy enhancement in the anterior dural sac was shown in 10 cases. Conclusion Intervertebral suppurative spondytitis had characteristic MRI findings, and the key to correct diagnosis was to combine MRI finding with clinical characteristics.