Study Of Energy Spectrum CT In Carotid Body Tumor

Objective:To explore the value of single energy image of CT energy spectrum in optimizing the image quality of carotid body tumor and the value of quantitative parameters of CT energy spectrum in evaluating the differentiation of carotid body tumor.Methods: The patients with carotid body tumor who underwent CT energy spectrum examination of head and neck and confirmed by operation in the Affiliated Hospital of Qinghai University from October 2020 to February 2022 were collected.The correlation between preoperative imaging features of carotid body tumor and surgical complications was recorded and analyzed.The single energy images of 40 ke V,50 ke V,60 ke V and 70 ke V in arterial phase and venous phase were reconstructed by GSI viewer.CT values,subcutaneous adipose tissue noise(SD),contrast noise ratio(CNR)and signal to noise ratio(SNR)of carotid body tumor in arterial phase,feeding artery and venous phase were measured and calculated.The subjective score was evaluated by two doctors with double-blind 5-point method.The correlation between energy spectrum CT parameters and the grading system for adrenal phaeochromocytoma and paraganglioma(GAPP)was analyzed.Statistical analysis of the data showed that the difference was statistically significant(P < 0.05).Results:1.The transverse and longitudinal diameter of carotid body tumor,the extent of tumor surrounding the internal carotid artery and Shamblin classification were strongly correlated with the amount of intraoperative bleeding(r1=0.788,0.669,0.663,0.672,P1<0.001),and the number of feeding arteries was moderately correlated with the amount of intraoperative bleeding(r1=0.583,P1=0.001).The transverse and longitudinal diameter of carotid body tumor,the degree of tumor surrounding the internal carotid artery and Shamblin classification were moderately correlated with cranial nerve injury(r2=0.476,0.550,0.527,0.529,P2<0.01),and the number of feeding arteries was strongly correlated with cranial nerve injury(r2=0.629,P2<0.001).2.The subjective and objective scores of carotid body tumor in arterial phase,feeding artery and venous phase were 40 ke V,50 ke V,60 ke V,70 ke V and 120 k Vp like groups from high to low.There were significant differences in subjective scores,CT values,SD values and CNR values,but there was no significant difference in SNR values.There was no significant difference in CNR values between70 ke V and 120 k Vp like groups,adjacent single energy groups,but there was significant difference in CNR values among other groups.There was significant difference in SNR between 40 ke V and 120 k Vp like,70 ke V groups,but there was no significant difference in SNR between other groups.The subjective score,CT value,CNR value and SNR value of 40 ke V single energy image in arterial phase were significantly higher than those in venous phase,and there was no significant difference in SD value between them.3.There was no correlation between GAPP score and iodine concentration,energy spectrum curve slope and effective atomic number in arterial and venous phase of carotid body tumor(P>0.05).Conclusion: The best single energy level of carotid body tumor in arterial phase and venous phase is 40 ke V,and the image quality is significantly better than 120 k Vp like image,among which the image quality of arterial phase is higher than that of venous phase.The transverse and longitudinal diameter of carotid body tumor,the number of feeding arteries,the extent of tumor surrounding the internal carotid artery and Shamblin classification are positively correlated with the amount of intraoperative bleeding and cranial nerve injury.The number of feeding arteries is one of the important parameters to evaluate the complications of carotid body tumor surgery.40 ke V single energy image can effectively improve the display of feeding arteries of carotid body tumor and optimize the poor display of small vessels by conventional CTA.There was no correlation between energy spectrum CT parameters of carotid body tumor in arterial phase and venous phase and the degree of differentiation of carotid body tumor.