目的 探讨低剂量单源双能量CT 在跟腱撕裂诊断中的应用价值。方法 对 42例怀疑跟腱撕裂患者行双能量CT和MRI 检查，经查跟腱撕裂36例、正常6例。36 例跟腱撕裂患者中，25例跟腱完全撕裂均 经手术确诊；11例不完全性撕裂中，7例 经MRI随访确诊，4例经手术及MRI确诊。 6例跟腱正常患者，经查为跟骨粉碎性骨 折，骨折线累及跟腱附着处，手术明确及 MRI未见跟腱撕裂。行多平面重组(MPR)、 肌腱3D容积再现(VR)等二维及三维图像后 处理，用以显示跟腱；双能CT虚拟去钙质 成像诊断踝关节骨质水肿；计算撕裂及正 常跟腱80KeV图像与135 KeV图像上的CT 差，CT差=CT均值135-CT均值80。结果 99KeV 软组织图像窗上横断面结合MPR均能诊断 跟腱完全撕裂患者，诊断跟腱完全撕裂灵 敏性100%、特异性100%，诊断跟腱部分撕 裂的灵敏性81.8%、特异性100%；VR图像 上，诊断跟腱完全撕裂的灵敏性100%、 特异性100%，诊断跟腱部分撕裂的灵敏 性63.6%、特异性100%；虚拟去钙图上， 诊断骨质水肿患者灵敏性77.5%、特异性 80%。MRI诊断完全及部分跟腱断裂和骨质 肿患者的灵敏性100%、特异性100%，诊断 骨折的灵敏性40%、特异性100%。结论 双 能CT成像能有效诊断跟腱完全撕裂和部分 撕裂，发现骨折优于MRI、发现骨质水肿 差于MRI。

Objective To investigate the application value of low-dose single-source dual-energy CT and MRI in diagnosis of Achilles tendon rupture. Methods A total of 42 patients with suspected Achilles tendon rupture underwent dual-energy CT and MRI scanning.36 cases of Achilles tendon rupture and 6 cases of normal patients were tested. In 36 cases of Achilles tendon rupture patients, 25 patients with complete Achilles tendon rupture were diagnosed by MRI. 11 patients with partial rupture, 7 patients were diagnosed by follow-up MRI, 4 patients were diagnosed by operation and MRI. 6 patients with normal tendons were diagnosed as calcaneal fracture, the fracture line involved the attachment of the Achilles tendon. The operation was clear and no rupture of Achilles tendon was observed in operation. Two-dimensional and three-dimensional image post processing, such as multiplanar reconstruction(MPR), tendon 3D volume rendering(VR), to show Achilles tendon, dual-energy CT virtual decalcification imaging for diagnosis of ankle bone edema, calculation of tear and normal tendon CTD, CTD=CTmean135-CTmean80. Results 99KeV soft tissue image window combined with MPR can diagnose the complete rupture of Achilles tendon. The sensitivity and specificity of diagnosis of complete rupture of Achilles tendon were 100% and 100%, respectively.The sensitivity and specificity of diagnosis of partial rupture of Achilles tendon were 81.8% and 100%, respectively, on VR imaging, the sensitivity and specificity of diagnosis of complete rupture of Achilles tendon were 100% and 100%, respectively. The sensitivity and specificity of diagnosis of complete rupture of Achilles tendon were 63.6% and 100%, respectively, on virtual calcium removal imaging, the sensitivity and specificity of diagnosis of bone edema were 77.5% and 80% respectively. The sensitivity and specificity of MRI diagnosis of complete and partial Achilles tendon rupture and bone edema patients were 100% and 100%, respectively. The sensitivity and specificity of bone fracture patients were 40% and 100%, respectively. Conclusion Dual-energy CT imaging can effectively diagnose complete Achilles tear and partial Achilles rupture, and its performance of finding fracture was better than MRI, while finding bone edema was worse than MRI.