Baseline CT Signs And Their Dynamic Evolution Of Coronary Plaque Progression

Objective: By comparing the fllow-up and baseline Coronary CT angiography(CCTA)with at least two changes in plaque.To investigate the baseline CT signs and their dynamic evolution in Cornary plaque progression.Objective basis is provided for early diagnosis and treatment and understanding of the progression of vulnerable plaque,and avoiding cardiovascular events.Materials and Methods: This study retrospectively analyzed patients who are suspected suffer from Coronary artery disease and has did multiple(at least twice)CCTA examinations between November 2011 and December 2018.Baseline CCTA plaque signs were recorded.Baseline and follow-up CCTA examination intervals were6.0–79.2 months.The two CCTA scan mode and the image analysis methods are the same.Plaque length and maximum cross-sectional area were used to assess lesion plaque progression.Plaque progression was defined as a ≥10% increase in follow-up CCTA plaque length(L)and / or plaque maximum cross-sectional area(S)compared to baseline CCTA.Grouping: plaque progression group and plaque non-progress group.The plaque evaluation parameters:(1)Positive Remodeling Index: On the image workstation,combination the cross-section and curved planar reformation,manually measure the diameter of the vessel in plaque(mm),the diameter of the vessel in the proximal segment of the plaque(mm),and the diameter of the normal vessel in the distal segment of the plaque(mm).Remodeling index : the diameter of the vessel in plaque(mm)/ [(the diameter of the normal vessel in the proximal segment of the plaque(mm)+ the diameter of the normal vessel in the distal segment of the plaque(mm))/ 2].The vessel positive remodeling is defined as index ≥1.1.(2)Plaque CT value(HU): plaque CT value was measured on non-calcified plaque,the region of interest > 1.0 mm2,the largest area of interest with the largest cross-sectional area.repeating the measurement three times and take the average value.Low attenuation plaques are defined as CT values <30HU.(3)Spotty calcification: Spotty calcification is defined as the maximum diater of calcification <3mm in any direction.(4)Napkin Ring Sign: the napkin ring sign is defined as a ring-shaped high-attenuation zone surrounding the the low attenuation plaque core,but the high-attenuation zone CT value ≤ 130 HU,to exclude calcium deposition.(5)Plaque length(mm): plaque length from the proximal to the distal of the plaque was measured on the curved planer reformation image.(6)Maximum cross-sectional area(mm2): the plaque area was measured on the largest cross-sectional image of the plaque,and the average of three measurements was taken.All patients used second and third generation dual-source CT(SOMATOM Definition Flash,force,Siemens Healthcare,Germany).Patient position: supine position and raised arms.At first,patients was scanned with a heart plain scan,and from the plane of the tracheal carina to the lower edge of the heart.CT scan direction: From head to foot direction.The tracking was used to scan the layer of region of interest in ascending aortal.After the contrast medium was injected for 6 s,for the auto-trigger funtion.And the concentration of contrast medium was observed to be close to 100 Hu in the region of interest.Other parameters of coronary CT scan:Ggantry rotation time: 280ms/r,250ms/r;the detector parts and the collimator: 2x64x0.6mm,2x96x0.6mm;Z-axis non-focus technology acquisition: 2x128x0.6mm,2x128x0.6mm;Tube voltage: 120 k V or 100 k V;Tube current: 330~420m As/r,330~420m As/r;Reconstruction time resolution:75ms,66ms;Layer thickness: 0.75 mm,0.75mm;Layer spacing: 0.7mm,0.7mm;Field of view: 250~270mm,250~300mm;The matrix: 512x512,512x512;Image reconstruction algorithm: filtering filtered back projection(FBP),convolution kernel value of image reconstruction: B26 F,Bv40.Results:(1)There were 95 plaques in 58 patients,49(51.6%)in the plaque progression group,and 46(48.4%)in the plaque non-progress group.Among the 95 plaques,29(30.5%,29/95)non-calcified plaques,66(69.5,66/95)mixed plaques,20non-calcified plaques in the progression group,accounting for 69.0% of all non-calcified plaques;29 mixed plaques,accounting for 59.2% of all mixed plaques;9non-calcified plaques in non-progressive group,accounting for 31.0% of all non-calcified plaques,37 mixed plaques,accounting for 80.4% of all mixed plaques.There were no significant differences in hypertension,diabetes,hyperlipidemia,smoking history,age and follow-up time between the progression and non-progression groups(p>0.05).Baseline CCTA Spotty calcification and napkin ring sign were statistically different between the two groups(p<0.05);Plaque CT value and positive remodeling index were significantly different(p<0.01);plaque length and maximal cross-sectional area statistically different between the two groups(p>0.05).(2)In the progression group,the follow-up CCTA plaque CT value was lower than the baseline CCTA(p<0.05).Among 20 plaques,15 decreased,accounting for 75.0%.,2 increased,accounting for 10.0%;In the non-progression group,the follow-up CCTA plaque CT value was slightly higher than baseline CCTA(p>0.05),Among 9 plaques,one decreased,accounting for 11.1%,6 increased,accounting for 66.7%.positive remodeling index of the follow-up CCTA plaque was larger than the baseline CCTA in the progression group(p<0.05).Among 49 plaques,35 increased,accounting for 71.4%,2 decreased,accounting for 4.1%;the follow-up CCTA plaque positive remodeling index decreased compared with baseline CCTA in non-progression group(p <0.05),Among 46 plaques,21 decreased,accounting for 45.7%,7 increased,accounting for15.2%.Positive remodeling index were statistically different between the progression group and the non-progression group(p<0.05).(3)There were 39(41.1%,39/95)plaques with “one risk sign”,28(71.8%,28/39)plaques in the progression group,and11(28.2%,11/39)plaques in the non-progression group.There was statistically different between the two groups(p<0.05).There were 9(9.5%,9/95)plaques with“two risk signs”,7(77.8%,7/9)plaques in the progression group,2(22.2%,2/9)plaques in the non-progression group,there were statistically different between the progression group and the non-progression group(p<0.05);There were 5(5.3%%,5/95)plaques with “three risk signs”,4(80.0%,4/5)plaques in the progression group,one(20.0%,1/5)plaque in the non-progression group,there were statistically significant between the progression group and the non-progression group(p<0.05)).The more increased the number of risk signs(number of risk signs,1、2、3),the more proportional plaque progression in the progression group(71.8%、77.8%、80.0%).Conclusion:(1)The baseline CCTA plaque CT value,positive remodeling index,Spotty calcification and napkin ring sign were different between the progression group and the non-progression group(p<0.05),especially plaque CT value and positive remodeling index were significantly different in two groups(p<0.01);As the degree of risk signs increased,the risk factor of plaque progression increased.(2)The dynamic evolution of plaque signs were different between the progression group and the non-progression group.Plaque CT value decreased and positive remodeling index increased in the progression group.Nevertheless,plaque CT value was a slight increase trend,positive remodeling index decreased and point calcified plaques are reduced in the non-progressive group.In conclusion,The baseline CCTA plaque CT value and positive remodeling index may have more higher predictive value for plaque progression,and the evolution of plaque risk signs is different or even opposite in the progression and non-pregression groups.Perhaps the dynamic changes of risk signs are more higher predictive than static signs for cardiovascular events.