双层探测器光谱CT对肺动脉肉瘤的诊断及与肺栓塞的鉴别一例

Diagnosis of pulmonary artery sarcoma and differential diagnosis of pulmonary embolism with double-detector spectral CT:a case report

目的通过双层探测器光谱CT鉴别诊断肺动脉肉瘤(PAS)与肺栓塞(PE),为提高PAS的检出率,降低误诊率提供新思路。方法以回顾性研究的方式,在光谱CT平扫及增强中应用飞利浦星云工作站(ISP)重建1例PAS患者电子密度图、碘密度图及光谱曲线。在平扫图像中,选取升主动脉与右肺动脉干低密度区测量其电子密度值。在胸部增强图像中,选取PAS区与PE区分别测量其碘密度,并对PSA区与PE区光谱曲线进行对比。结果该PAS患者光谱CT平扫期升主动脉、右肺动脉干低密度区电子测值分别为104.4%EDW(相对于水的电子密度百分数)和102.2%EDW,较正常升主动脉区的电子密度偏低。混合能量与电子密度融合图清晰反映病灶范围。增强动脉期PAS区碘密度1.89 mg/ml,PE区碘密度0.03 mg/ml,PAS区摄碘明显高于PE区。PAS区斜率为2.08,PE区斜率为-1.86,二者光谱曲线斜率不一致。结论双层探测器光谱CT测得的电子密度、碘密度与光谱曲线或可为诊断PAS并与PE鉴别提供有力的影像学依据,有助于病灶的早期诊断,同时可为PAS与PE混合病灶的活检定位提供依据。

Objective The differential diagnosis of pulmonary artery sarcoma(PAS)and pulmonary embolism(PE)by double-detector spectral computerized tomography(CT)provides a new way to improve the detection rate of PAS and reduce the misdiagnosis rate.Methods In the way of retrospective study,the Philips Nebula Workstation(ISP)was used to reconstruct electron density map,iodine density map and spectral curve in the spectral CT plain scan and enhancement of the PAS patient.In the plain scan image,the low density areas of the ascending aorta and the right pulmonary trunk were selected to measure their electronic density values.In the chest enhancement image,the iodine density of PAS area and PE area were measured respectively,and the spectral curves of PSA area and PE area were compared.Results The electron density of the ascending aorta and the right pulmonary trunk in the low density area of the PAS patient during the plain scan of spectral CT were 104.4%EDW(relative to the percentage of the electron density of water)and 102.2%EDW,respectively,which were lower than those in the normal ascending aorta area.The fusion image of mixed energy and electron density clearly reflected the scope of the lesion.The iodine density in PAS area was 1.89 mg/ml,and the iodine density in PE area was 0.03 mg/ml during the enhancement phase.The iodine uptake in PAS area was significantly higher than that in PE area.The slope of PAS region was 2.08,and the slope of PE region was-1.86.The slopes of the two spectral curves were inconsistent.Conclusions The electronic density,iodine density and spectral curve measured by double-detector spectral CT may provide powerful imaging basis for the diagnosis of PAS and the differentiation of PAS from PE,which is helpful for the early diagnosis of the lesions,and also provide basis for the biopsy location of the mixed lesions of PAS and PE.