The Preliminary Research Of Low Field Magnetic Resonance Imaging To Normal Posterolateral Corner Of The Knee

objective:To use low field magnetic resonance preliminary study scanning localization way about three main structures(fibular collateral ligament,popliteus tendon and popliteofibular ligament)of posterolateral corner(PLC)of the knee,by comparing the complete display rate under different localization way about the three structures,and selecting idealer MRI display mode,make conditions for imaging diagnostic and clinical treatment of PLC injury of the knee.Methods:Selecting randomly 52 clients without knee injury history,a total of 104 knees,male 27 cases,female 25 cases,aged 10-61 years old,an average of 34.2 years,four of 104 cases have joint effusion history but no clear injury history,the rest of the volunteers don't have significantly knee discomfort,physical examination did not find the obvious exception.Using XGY0.3T open magnetic resonance imaging system and knee special orthogonal coil.Scanning parameters:fast spin echo(FSE)sequence,TR3000ms,TE 105ms,FOV200mm,matrix 256×175,slice thickness 3 mm,gap 1 mm.Making conventional sagittal,conventional coronary and oblique coronary scanning respectively,and analysing the display effect of fibular collateral ligament,transitional part of popliteus tendon and popliteofibular ligament.Results:Fibular collateral ligament of 104 knees display completely on conventional sagittal,conventional coronary and oblique coronary 10,72,98 cases,the display rate is about 9.62%,69.23%,94.23%.Transitional part of popliteus tendon of 104 knees display completely on conventional sagittal,conventional coronary and oblique coronary 0,12,60 cases,the display rate is 0,11.54%,57.69%.Popliteofibular ligament of 104 knees display completely on conventional sagittal,conventional coronary and oblique coronary 6,14,56 cases,the display rate is about 5.77%,13.46%,53.85%.The complete display rate of oblique coronary scanning to the fibular collateral ligament,transitional part of popliteus tendon,popliteofibular ligament is higher,especially to fibular collateral ligament the oblique coronary scanning shows the highest rate.The oblique coronal scanning can completely show fibular collateral ligament in continuous two levels.The complete display rate of conventional coronary scanning to fibular collateral ligament is also higher.Conventional sagittal scanning can't show the transitional part of popliteus tendon on one level completely,but it can show the popliteus tendon section on several continuous levels.The popliteus muscle,muscle tendon junction,transitional part of tendon and part of femur can be shown in several continuous levels.When there is some liquid in popliteus capsule,it will be more beneficial to display the popliteus tendon.The oblique coronal scanning can greatly improve the complete display rate of transitional part of popliteus tendon.The oblique coronal scanning obviously improved the complete display rate of popliteofibular ligament,especially when the transitional part of popliteus tendon is shown completely in one level,the popliteofibular ligament is more likely to be shown at the same time.When the popliteofibular ligament is shown in a conventional coronary image,in the oblique coronary image most of them will not be displayed.The oblique coronal scanning can also shows the fibular collateral ligament,transitional part of popliteus tendon,popliteofibular ligament completely at the same time.Conclusions:there is obvious advantage on low field magnetic resonance machine do oblique coronary scanning to display three main structures of the knee PLC,and the method is simple and easy to operate,it can be used as important display mode to the knee PLC structure,and complement with the conventional coronary scanning and conventional sagittal scanning to improve the display rate and diagnostic accuracy.