创伤性膝关节脂血症和血症的影像诊断

Radiographical diagnosis of posttraumatic knee joints bemarthrosis and lipohemarthrosis

目的探讨膝关节脂血症和血症的X线平片、CT、MRI、超声的影像表现及其诊断价值。方法对经手术（27例）或穿刺（3例）证实的关节血症（12例）及脂血症（18例）的仰卧位水平摄影X线平片（16例）、CT（30例）、MRI（30例）、超声（24例）4种影像检查方法和结果进行研究。结果（1）X线平片：9例脂血症中8例见脂-液平面，1例脂血症和7例血症见髌上囊密度增高，与肌肉近似。正确诊断骨折13例。（2）CT：18例脂血症中双液-液平面11例，单液-液平面7例。12例血症中3例见单液-液平面。9例呈中等密度，4例见卵圆形稍高密度血凝块。30例均正确诊断骨折。（3）MRI：18例脂血症中12例呈双液-液平面，上层呈短T1、长T2高信号及压脂像低信号，中层呈长T1、长T2信号及压脂像高信号，下层呈中等T1、T2信号及压脂像较高信号；6例呈单液-液平面。12例关节血症仅见上述的中、下2层。4例见边缘光滑的血凝块，在T1WI呈中等信号或中等信号伴高信号环，压脂像呈高信号，T2WI及压脂像呈中等或稍高信号伴低信号环。30例均正确诊断骨折。（4）超声：14例脂血症中双液-液平面10例，上层呈中等回声，中层无回声，下层呈云雾状回声；单液-液平面4例。10例关节血症中3例见单液-液平面，即仅见上述的中、下2层；7例呈云雾状回声并见漂浮状物。3例血凝块呈低-等回声类实性团块。均未见骨折线。结论CT能很好地显示骨折线及关节脂血症和血症，可以替代X线平片。MRI是该病的最佳影像检查方法。超声可诊断关节脂血症和血症，但不能显示骨折。

Objective To explore the imaging findings and diagnostic values of X-ray, CT, MR, and ultrasonography in traumatic knee joints hemarthrosis and lipohemarthrosis. Methods Traumatic knee joints hemarthrosis （12 knees） and lipohemarthrosis （18 knees） proved by operation （27 knees） or puncturation （3 knees ） were included in the study. Horizontal-beam plain radiographs （16 knees ）, CT （30 knees）,MRI（30 knees） and uhrasonography（24 knees） in supine position were investigated. Results （1）supineposition horizontal-beam plain radiographs： Fat-liquid layer was found in 8 cases of lipohemarthrosis. Dense supragenual bursa was found in 1 case of lipohemarthrosis and 7 cases of hemarthrosis. Fracture （13 knees） was diagnosed correctly. （2） CT findings： double fluid-fluid layer was found in 11 of all 18 cases, and single fluid-fluid layer was found in 7 of 11 cases of lipohemarthrosis. Single fluid-fluid layer was found in 3 of 12 cases of hemarthrosis. Isodensity was detected in 9 cases, and high- density blood clot was found in 4 cases. Fracture （30 knees） was diagnosed correctly. （3） MRI findings： in 12 of 18 cases of lipohemarthrosis, double fluid-fluid layer was shown including supernatant layer as short T1, long T2 signal and low signal after fat-suppression, middle layer as long T1 , long T2 signal and high signal after fat-suppression, and dependent layer as iso-T1, iso-T2 and slight high signal after fat-suppression. Single fluid-fluid layer was seen in 6 cases, only had aforementioned upper and under layer. Only aforementioned supernatant layer and dependent layer were seen in 12 cases of hemarthrosis. 4 cases showed entire blood clot in fluid, T1WI showed middle signal or center iso-signal accompanied with peripheral high signal ring, and fat-suppression imaging showed high signal. T2WI and fat-suppression imaging showed middling or high signal accompanied with peripheral low signal ring. Fracture （30 knees） was diagnosed correctly. （4） Ultrasound findings： In 10 of 14 cases of lipohemarthrosis, double fluid-fluid level was shown, supematant layer as equal echo, middle layer as echoless, and dependent layer as cloudy echo. Four cases with single fluid-fluid level only showed aforementioned upper and under layer. Three of 10 cases of hemarthrosis showed single fluid-fluid level, only showing aforementioned upper and under layer, and 7 cases showed cloudy echo and float. In 3 cases the fluid blood clot showed irregular shape low- equal echo bolus. No fracture line was found. Condusions CT can clearly detect fracture line, hemarthrosis and lipohemarthrosis, and can substitute plain radiography. MRI is the best way to diagnose hemarthrosis and lipohemarthrosis. Uhrasonography can be used in diagnosing hemarthrosis and lipohemarthrosis but not helpful in the diagnosis of fracture.