质子脂肪抑制序列在四肢隐性骨折中的诊断价值

目的探讨质子脂肪抑制序列(PDFASAT)在四肢隐性骨折中的诊断价值。方法31例四肢关节外伤患者在伤后45d内均行X线平片及多序列高场强(1．5T)MR检查，检查序列包括快速SE T1WI、T2WI，PDF ASAT等。受伤部位为膝关节21例，髋关节6例，肘关节1例，肩关节2例，踝关节1例。结果31例X线平片均未见明显骨折征象。MR检查发现：21例(21／31)膝关节受伤病例中腓骨近端隐性骨折10例，胫骨近端4例，股骨髁7例；6例(6／31)髋关节受伤病例中粗隆问隐性骨折2例，股骨颈隐性骨折2例，髋臼隐性骨折2例；1例(1／31)肘关节受伤病例显示肱骨远端隐性骨折；2例(2／31)肩关节受伤病例显示肱骨近端隐性骨折；1例(1／31)踝关节受伤病例显示腓骨远端隐性骨折；MR信号主要表现为T1WI、T1WI呈细线状、条带状低信号影，PDFASAT呈更清晰锐利的细线状、条带状高信号影，PDFASAT序列更易认识辨别。结论MRI能发现早期至慢性期隐性骨折的存在，如临床强烈提示骨折可能而X线检查阴性者，MR检查的PDFASAT序列是明确诊断的最佳序列。

The value of MR imaging of PDFASAT sequence in the diagnosis of extremities occult fractures

Objective To investigate the value of MR imaging of proton density weighted fat saturated (PDFASAT) sequence in detecting the occult fracture of extremities Methods Thirty one patients with acute trauma were studied using radiography and MR imaging within 45 days MR sequences included FSE T 1WI, T 2WI, and PDFASAT 21 occult fractures occurred in the knee joint, 6 in the hip joint, 1 in the elbow joint, 2 in the shoulder, and 1 in the ankle Results All 31 cases had normal radiographic results 10 cases with proximal fibula, 4 with proximal tibia and 7 with femur condyle occult fractures were found in 21 knee joint acute trauma cases 2 cases with intertrochanteric, 2 with femoral neck and 2 with cotyle occult fractures were found in 6 hip joint trauma cases 2 proximal humerus occult fractures were found in 2 shoulder cases 1 distal humerus and 1 distal fibula occult fracture was found in elbow and ankle cases MR imaging demonstrated irregular linear low signal in the subcortical region on both T 1WI and T 2WI, and high signal changes around low signal were seen on T 2WI in some cases The high signal in PDFASAT sequence was more remarkable and wider than that on both T 1WI and T 2WI Conclusion MR imaging could determine the diagnosis of acute and chronic occult fractures MRI should be the next choice when plain films fail to reveal suspected fractures in setting of suggestive symptoms and positive physical examination PDFASAT would be the best effective sequence among the T 1WI, T 2WI, and PDFASAT