Study On Biomechanical Characteristics Of Carotid Isolated Plaques Using Intima-media Thickness Automatic Tracking Technique

Objective To assess the biomechanical characteristics of carotid isolated plaques us-ing intima-media thickness?IMT?automatic tracking technique along with acoustic densitometry?AD?,and to investigate the relationship between biomechanical charac-teristics and inflammatory activity of carotid isolated plaques evaluated by ¹⁸F-FDG PET/CT.Methods The study included 61 patients who had isolated plaques in carotid artery.IMT strain rate?SR?,IMT time strain rate?TR?and AIIc%were measured by IMT automatic tracking technique along with AD to assess the variation of the IMT and acoustic density in the upstream,fibrous cap top and downstream regions of the plaque and ipsilateral normal carotid.Select the normal intima of the adjacent plaque of the same carotid artery in the same patient as the control group.TBR was acquired by ¹⁸F-FDG PET/CT for evaluating the radioactive activity of corresponding isolated plaques.All participants were divided into inflammatory group with its TBR?1.25 and non-inflammatory group with its TBR<1.25 according to ¹⁸F-FDG PET/CT.The differences of SR,TR and Allc%in the two groups were compared,and the relationship between TBR value and various biomechanical characteristic param-eters was discussed.Results1.SR and TR were significantly reduced in plaques group when compared with con-trols.SR and TR at the cap top area?CTA?and downstream area?DA?of the plaques were lower than those in the control group?p<0.05?,while there was no statistical-ly significant difference in SR,TR between the upstream area?UA?and the control group.2.Compared with CTA and DA,The SR,TR of UA were significantly in-creased.Meanwhile,the SR,TR of CTA were significantly higher than DA.3.AIIc%in UA and CTA were significantly lower than DA.The SR,TR for the 3plaque regions were negatively correlated with AIIc%?r=-0.74,r=-0.75;p<0.05?.AIIc%in all three regions were significantly higher than that in control group.4.TR in inflammatory group were significantly lower than non-inflammatory group?p<0.05?,while SR,AIIc%showed no significant difference?p>0.05?.TR has a significant negative correlation with TBR?r=-0.83;p<0.05?.ROC curve analysis showed that the area under the curve?AUC?of TR was 0.87,and TR less than75.06‰had a sensitivity of 88.0%and a specifictively of 80.6%for the identification of inflammatory plaques.ConclusionIMT automatic tracking along with AD could be applied to identify the anisotropic biomechanical features in carotid isolated plaques,may be a new noninvasive way to early assess the biomechanical characteristics of carotid plaque.And the parameter TR was associated with plaque inflammation reaction,may provide a new indicator for the early identification of plaque vulnerability.