Objective To explore the MRI appearances of heterotopic gray matter. Methods The appearances of MRI of heterotopic gray matter(n=12) confirmed were analyzed retrospectively. Results In the 12 cases,3 lesions were nodular,9 lesions were lamellar. MRI can clearly show the lesions. On T1-WIs and T2-WIs,these lesions appeared isointense to the normal gray matter. 2 lesions associated with arachnoid cyst,2 lesions with schizencephaly and 1 lesion with dysgenesis of the corpus callosum and lipoma of midline. During contrast on MRI(n=5) ,all lesions show unenhancement. Conclusion The MRI have characteristics in diagnosis of heterotopic gray matter and is the best method.

Objective:To investigate the clinical efficacy of over-the-top reconstruction combined with the modified Lemaire technique in the treatment of anterior cruciate ligament (ACL) injuries with pivot-shift positive.Methods:From March 2020 to October 2021, a total of 46 patients with ACL injury and pivot-shift test grade II or above were admitted to Xinhua Hospital Affiliated to Dalian University. There were 28 males and 18 females, aged 28.0±10.5 years (range, 15-45 years). All cases were unilateral, including 17 cases of left knee and 29 cases of right knee. The pivot-shift test showed that 30 cases were grade II and 16 cases were grade III, and the cause of injury was sports injury. The semitendinosus muscle and gracilis muscle were harvested, and the ACL was reconstructed with the over-the-top combined modified Lemaire technique. The International Knee Documentation Committee (IKDC) score, Lysholm score and KT-2000 side-to-side difference before and after operation were compared.Results:All patients successfully completed the operation and were followed up for 26.6±2.3 months (range, 24-28 months). The Lysholm scores of the patients at 3 months and 24 months after operation were 73.6±4.3 and 91.6±2.8, which were higher than those before operation (58.5±4.6), and the difference was statistically significant ( F=18.351, P<0.001). The IKDC scores of patients at 3 months and 24 months after operation were 59.0±2.0 and 91.8±3.2, respectively, which were higher than those before operation 50.3±2.8, and the difference was statistically significant ( F=17.290, P<0.001). The side-to-side difference of KT-2000 was 1.7±0.8 mm and 1.5±0.4 mm at 3 and 24 months after operation, respectively, which was lower than that before operation (5.9±1.1 mm), and the difference was statistically significant ( F=14.192, P<0.001). At 24 months after operation, 3 patients had pivot shift test grade I and 4 patients had Lachman test grade I, but they complained of good knee stability and did not receive further treatment. At the last follow-up, there were no complications such as incision and intra-articular infection, deep vein thrombosis, knee stiffness, quadriceps musculus ossificans myositis, and reconstruction ligament rupture. All patients returned to sports with an average time of 15.7±2.6 months (range, 12-24 months). Conclusion:Over-the-top reconstruction combined with the modified Lemaire technique for the treatment of ACL injury with positive pivot shift test effectively improves knee function and promotes the patient's return to sports, with a low incidence of surgical complications.