ABSTRACT
Objective To assess the relationship between plaque burden (PB) and area strain (AS) by intravascular ultrasonic elastography (IVUSE).Methods Forty purebred New Zealand rabbits were fed with a high-cholesterol diet.And the abdominal aorta endothelium was balloon-injured after 2 weeks.At the end of the 12th week,2 plaques with moderate echo from each rabbit were chosen for in situ imaging,and 2 consecutive frames near the end-diastole images in situ were used to construct an IVUS elastogram.Cross-sectional external elastic membrane area (EEMare),lumen area (Lumenarea),plaque area (PA),PB,external elastic membrane volume (EEMvolume),lumen volume (Lumenvolume),plaque volume (PV),plaque volume burden (PVB),maximal plaque thickness (Tmax) and minimal plaque thickness (Tmin),eccentric index (EI),remodeling index (RI) and AS were measured and calculated,respectively.According to the PB,the plaques were divided into low PB group (PB≤40 ％) and high PB group (PB＞ 40 ％).The differences of all above parameters between the two groups were compared,and the relationship between the plaque morphological and mechanical parameters were analyzed.Results PA,PV,PB,PVB,Tmin,Tmax,Lumenarea,Lumenvolume and EI were different between the 2 groups (all P＜0.01).On stepwise multiple regression analysis,the regression equation were built,(Y)=-6.921+10.430X1 +12.207X2((Y):AS,X1:EI,X2:PB,R2 =0.272,P＜0.001).After eliminating the effect of EI on the AS,the lower PB group had obviously smaller AS than higher PB group (P =0.010).Conclusion The PB has effect on plaque mechanical stability.The plaques with higher burden are more vulnerable than those with lower burden.
ABSTRACT
Objective To assess the relationship between plaque burden (PB) and area strain (AS) by intravascular ultrasonic elastography (IVUSE).Methods Forty purebred New Zealand rabbits were fed with a high-cholesterol diet.And the abdominal aorta endothelium was balloon-injured after 2 weeks.At the end of the 12th week,2 plaques with moderate echo from each rabbit were chosen for in situ imaging,and 2 consecutive frames near the end-diastole images in situ were used to construct an IVUS elastogram.Cross-sectional external elastic membrane area (EEMare),lumen area (Lumenarea),plaque area (PA),PB,external elastic membrane volume (EEMvolume),lumen volume (Lumenvolume),plaque volume (PV),plaque volume burden (PVB),maximal plaque thickness (Tmax) and minimal plaque thickness (Tmin),eccentric index (EI),remodeling index (RI) and AS were measured and calculated,respectively.According to the PB,the plaques were divided into low PB group (PB≤40 ％) and high PB group (PB＞ 40 ％).The differences of all above parameters between the two groups were compared,and the relationship between the plaque morphological and mechanical parameters were analyzed.Results PA,PV,PB,PVB,Tmin,Tmax,Lumenarea,Lumenvolume and EI were different between the 2 groups (all P＜0.01).On stepwise multiple regression analysis,the regression equation were built,(Y)=-6.921+10.430X1 +12.207X2((Y):AS,X1:EI,X2:PB,R2 =0.272,P＜0.001).After eliminating the effect of EI on the AS,the lower PB group had obviously smaller AS than higher PB group (P =0.010).Conclusion The PB has effect on plaque mechanical stability.The plaques with higher burden are more vulnerable than those with lower burden.
ABSTRACT
Objective To assess the relationships between area strain (AS) and eccentric index (EI) of atherosclerotic plaques as seen by intravascular ultrasonic elastography (IVUSE),and to reveal the effect of EI on the plaques stability.Methods Forty purebred New Zealand rabbits were fed with a high-cholesterol diet;the abdominal aorta endothelium was balloon-injured after 2 weeks;at the end of week 12,2 plaques with moderate echo from each rabbit were chosen for in situ imaging,and 2 consecutive frames near the end-diastole images in situ were used to construct an IVUS elastogram.Results The eccentric plaques showed significantly greater area stain (AS) than the centripetal plaques [4.77(2.92,8.01)% vs 3.27(2.15,4.82)%,P=0.029] with smaller plaque area and plaque burden (P<0.05).The plaque AS was positively correlated with EI (r=0.392,P=0.003).The eccentric plaques showed significantly greater AS in the shoulder than in body [4.98(3.17,8.48)% vs 4.64(2.51,5.92)%,P=0.008].Conclusions The EI is one of influential factors on plaque AS.Eccentric plaques may be more vulnerable than centripetal plaques,especially in the shoulder of eccentric plaques which have greater AS than their body.
ABSTRACT
Objective To evaluate left ventricular (LV) myocardial contraction patterns and function by analyzing the distribution of peak value of segmental area strain and time sequence to the peak value.Methods 31 healthy subjects were involved.Real-time three dimensional full volume images of LV were acquired and analyzed with EchoPAC.LV volume and function parameters,as well as segmental and global systolic area strain and time to peak value were measured.The distribution of peak segmental area strain and time sequence to the peak value,interobserver and intraobserver variability of area strain parameters,as well as the relationship between global area strain and ejection fraction were evaluated.Results The peak segmental area strain was lower in the basic inferior and apical segments,and the peak value was reached earlier in the basic inferior,anteroseptal,and septal segments.Intraobserver and interobserver reliability of area strain parameters were good.Furthermore,a negative correlation was observed between global area strain and ejection fraction (r =-0.688,P =0.000).Conclusions The area strain measured by 4D strain can be used to evaluate the LV myocardial motion pattern and function.