肺栓塞动物模型(猪)V/Q SPECT显像与平面显像的对比

目的应用201Tl标记栓子制作肺栓塞动物模型(猪),比较肺V/QSPECT显像和平面显像的灵敏度、特异性和准确性,探讨肺通气显像在肺栓塞诊断中的意义及V/Q显像在亚肺段肺动脉栓塞(PE)诊断中的作用。方法16头试验用小型猪,栓塞前应用不同技术参数行99Tcm窗肺灌注平面及断层显像,每头猪分别置入0～3个栓子,栓塞后行99Tcm窗及201Tl窗双窗肺通气平面、断层显像及99Tcm窗肺灌注平面、断层显像。最后行X线平片或CT显像并进行肺脏解剖确定栓子位置。结果共可见栓子28个,其中17个位于左肺,11个位于右肺。平面显像的敏感性、特异性和准确性分别为75%、75%和75%,而断层显像的敏感性、特异性、准确性分别为100%、75%和96.9%。结论肺通气/灌注断层显像的灵敏度及准确性均较平面显像高,而特异性两者相同。同时行V/Q显像可提高肺栓塞的诊断率。V/QSPECT断层显像可提高亚肺段性PE的诊断率。选用低能通用准直器、平面显像矩阵128×128、断层影像Zoom1.46可较好的满足临床诊断需要。

Comparison of Pulmonary V/Q SPECT and Planar V/Q Imaging in the Artificially Embolized Pig

Objective To compare the sensitivity,specificity and accuracy between pulmonary V/Q SPECT and planar V/Q imaging using pigs with artificially engendered lung emboli labeled with ²⁰¹Tl.To investigate the value of ventilation imaging in the diagnosis of pulmonary embolism(PE).To investigate the value of V/Q imaging in the diagnosis of subsegmental pulmonary embolism(PE).To understand how the different acquisition parameters of V/Q SPECT imaging,i.e.different matrix size(64×64 matrix,128×128 matrix),type of collimator(low energy general purpose collimator,high resolution collimator) and different enlargement factor used will affect the data gathering process.Methods Using different acquisition parameters in ⁹⁹Tc^m windows,SPECT and planar pulmonary perfusion imaging were done on the sixteen small experimental pigs before being embolized.Each pigs was subsequently injected with zero to 3 latex flat emboli and a planar and SPECT pulmonary ventilation imaging was performed in ⁹⁹Tc^m and ²⁰¹Tl windows,followed with planar and SPECT pulmonary perfusion imaging in ⁹⁹Tc^m windows.Lastly,X-ray、CT scan and lung autopsy were done to ascertain the definite embolus position.Results Of the 28 emboli,17 are lodged in the left lungs and 11 are located in the right lungs.The planar images of these pig,sensitivity,specificity and accuracy were 75%,75% and 75%,respectively,whereas V/Q SPECT yielded 100%,75% and 96.9%,respectively.Conclusion Pulmonary V/Q SPECT imaging is more sensitive and more accurate than planar imaging,but specificity is the same for both.A combination of pulmonary ventilation imaging and perfusion imaging may enhance the diagnostic power of PE.Pulmonary V/Q SPECT imaging may enhance the diagnostic power for the detection of lesions at the subsegmental level.Using low energy general purpose collimator,128×128 matrix for planar imaging and Zoom 1.46 for SPECT will satisfy the demand of diagnosis and clinic.