Purpose: to compare diagnostic capabilities of an innovative ultra high frequency ultrasound (HFUS) system with conventional-US and Contrast Enhanced MR Angiography (CEMRA) in the evaluation of atherosclerotic carotid plaque in order to categorize stable vs unstable atheromas.
Methods and Materials: 16 carotid plaques (11 patients), causing at least a 30% luminal stenosis, were analyzed. Patients underwent to: Color-Doppler US, HF US and CEMRA. Parameters evaluated were: • Qualitative: Presence/absence hyperechoic spots and of hypoechoic core; fibrous cap (FC) delineation• Quantitative: main plaque and lipid core diameters; fibrous cap thickness
Results: HFUS was able to discriminate qualitative characteristics in all plaques. Quantitative values showed significant differences: using HFUS bigger dimensions were measured (mm 4.7-7.8, 6.7-8.7, 3.7-5.8 on three axes), as the lipid core (mm 0.8-2.1, 0.8-1.5, 1.2-2.4). FC thickness showed specific values on High Frequency US (0.10-1.5 upward; 0.45-1.7 downward) while it was clearly assessable only in 3 patients at conventional US. MRI showed always the FC but a precise dimension was never assesable.
Conclusion: HFUS is a reliable technique in defining qualitative and quantitative carotid plaque features, highlighting dimensions of the plaque, size of the lipid component, and thickness of the fibrous cap, known as most important predictors of atheroma vulnerability. Moreover this new technique has good reproducibility, fast speed of execution and good spatial resolution, in the absence of ionizing radiation.
Purpose: To investigate the correlation between contrast-enhanced ultrasound perfusion patterns of carotid artery vulnerable plaque and the degree of carotid stenosis, which provides the basis for early diagnosis of cerebral ischaemic stroke.
Methods and Materials: From March 2018 to June 2018, 202 patients with carotid plaque who underwent CEUS were enrolled in this study. The patients who did not undergo CTA or DSA examination within 1 weeks after CEUS examination were excluded. The stenosis of carotid artery was determined by CTA or DSA as gold standard. Finally, 80 patients were analysed (35 patients in the stenosis group and 45 patients in the non-stenosis group). The appearance of enhancement in plaques were observed and the enhancement level of the plaques was divided into I-IV grades according to enhanced ultrasound findings of carotid plaques. The patients were divided into plaque base entering mode and plaque surface entering mode by the CEUS perfusion pattern when the contrast agent enters the plaque. The correlation between the CEUS perfusion pattern and the degree of carotid stenosis was analysed.
Results: The enhanced level of carotid plaque between the stenosis group and the non-stenosis group showed statistically significant difference. The plaque of the stenosis group and the non-stenosis group entered the plaque with different patterns, and the difference was statistically significant.
Conclusion: There remains a significant correlation between the enhancement level of carotid plaque and the degree of carotid stenosis, and the different CEUS perfusion patterns are closely correlated with the degree of carotid stenosis.
Purpose: To compare semi-automatic plaque quantification on different energy levels of DECT to inform standardization efforts for single-energy protocols where difference is to be avoided, as well as to explore opportunities in multi-energy protocols where differences are intended.
Methods and Materials: Retrospective study enrolling 36 patients who underwent DECT of the carotids. Seven energy levels were reconstructed (keV: 40, 66, 70, 76, 86, 100, 120). Plaque subcomponent analysis was performed for each energy separately, without modifying lumen and wall segmentations using commercially available software (vascuCAP, Elucid Bioimaging).
Results: Normality of each energy was tested using the Kolmogorov-Smirnov Z test. Since most were not distributed normally, a Wilcoxon test was performed to check differences with a p value <0.05. Differences of component volumes were in the order of the reproducibility coefficient (RDC) at the closest energy levels (calcium 66keV vs 70keV : Z value:-2.1; p≤0.05; LRNC 66keV vs 70keV; Z value:-2.5, p≤0.05; Matrix 66keV vs 70keV:-2.3, p≤0.05), and documented that differences increased with difference in energy.
Conclusion: Plaque component analysis has been known to provide important prognostic information on plaque progression and adverse acute cardiovascular events. We established that standards efforts should specify differences of no greater than ±2 keV for single-energy protocols, and have established base data on which exploiting intended differences might be of value were they to be processed by algorithms designed to exploit these differences beyond what single energy may reasonably be expected to do, such as speculated vs. dense calcium, or differing stages of IPH, for example.
Purpose: There are several causes for cerebral ischaemia and if risk factors are diagnosed timely, the risk of stroke can be significantly reduced. One of the main risk factors for cerebral ischaemia is the unstable atherosclerotic plaque in the arteries. The purpose of the study was to analyse multi-parametric US techniques ability to confirm the plaque's instability more precisely than the baseline investigation of Duplex US.
Methods and Materials: In prospective research conducted in the period from 2017 to 2018, were included 22 patients with unstable plaque which were detected with duplex, every patient was analyzed with CEUS, SMI and CTA methods. The results were histologically proven in 8 cases.
Results: Unstable plaque was diagnosed in 22 patients using duplex and in 21 patients using CT. Comparing both methods statistically significant correlation was found (rs = 0,781; p = 0,0001), The neovascularization was diagnosed in 13 (59.1%) patients by CEUS - in 6 (46.2%) plaques showed neovascularization grade 1 and in 7 (53.8%) plaques were detected grade 2. Using SMI method neovascularization were found in 12 (54.5%) patients, with statistically significant correlation between CEUS and SMI (r s = 0,801; p = 0,0001). Histology showed vasa vasorum presence in all CEUS positive cases from 2-23 microvessels with positive tendency (p>0.05) within endarterectomy material and significant difference with positive correlation to stenosis grade (70-90%) (p=0.03)
Conclusion: New ultrasound methods such as CEUS and SMI provide additional information on detecting aterosclerotic plaque instability and vasa vasorum with positive correlation to stenosis grade.
Purpose: To evaluate the incidence of intra- and early post-procedural micro-embolism during Carotid Artery Stenting and the role of DW-MRI in the characterization of carotid plaque activity.
Methods and Materials: This prospective study included 50 patients who underwent CAS with two different mesh-covered stents. All patients had carotid plaque DW-MRI pre-procedure (except for patients with re-stenosis after endarterectomy, 13/50, 26%), brain DW-MRI pre-proc., at 1h, 24h and 30 days post-proc., clinical evaluation and Doppler US pre-proc., at 24h and 30 days post-proc. Imaging analysis (quantitative and qualitative) was performed in a double-blinded fashion by two radiologists.
Results: No statistically significant differences between the two type of stents both in the incidence at 1h (p=0.23), 24h (p=0.36) and in the volume of new brain lesions at 24h (p=0.27). A total of 34 new lesions in 19 patients (38%) were found: 4 (11.8%) at 1h, 30 (88.2%) at 24h post-proc. The 30-day DWI-MR showed complete resolution of all lesions and no evidence of new lesion. The incidence of new lesions at 24h resulted higher in patients with positive carotid plaque DW-MRI (12/16, 75%, vs. 0/21, 0%, with a LR+ of 6.25), results paralleled by the ADC value (0.83+/-0.21 vs 1.42+/-0.52).
Conclusion: The majority of early asymptomatic brain lesion did not occur during the procedure but in the ensuing 24h. A positive pre-proc. carotid DW-MRI was associated with an increased incidence of micro-embolizations after CAS.
Purpose: The aim of study was to estimate the frequency of ultrasound-assessed changes in carotid arteries in patients with hypertension after a stroke.
Methods and Materials: 111 patients were qualified for the study. They represented two study groups: patients with arterial hypertension after a stroke in their medical history (group A, n=59) and patients with arterial hypertension without stroke in the medical history (group B, n=52). In the studied group an ischemic stroke was observed in 88.1%, and a hemorrhagic stroke- in 11.9%. Ultrasound examination of carotid arteries was carried out in all patients.
Results: Significantly higher IMT (intima-media thickness) was observed in group A in comparison to group B (1.09±0.23 mm vs.0.87±0.31 mm; p<0.05). The remaining parameters of ultrasound examination of carotid arteries didn't differentiate group A from group B. The type of stroke, the time elapsed since the stroke and the number of ischemic events didn't determine statistically significant differences in ultrasonography of carotid arteries in contrast to the effectiveness of blood pressure control. In group A, patients with well-controlled hypertension were characterized by lower IMT than patients with non-controlled hypertension (0.95±0.24 mm vs. 1.24±0.21 mm; p<0.05). The regression analysis showed that higher BMI and higher blood glucose concentrations are independent risk factors for higher IMT, while the use of β-blockers is an independent protection factor against higher IMT.
Conclusion: In the studied group of patients with hypertension after a stroke, the IMT value in ultrasound examination of carotid arteries may constitute an indicator of high prognostic significance.
Purpose: Combining 2D ultrasound High-frame rate Vector Flow (HiFR-VF) and 3D Computational Fluid Dynamics (CFD) on the carotid bifurcation (CB) may allow the clinical validation of a new approach to obtain a comprehensive assessment of the blood flow field. This initial study aimed at ensuring the effectiveness of a protocol designed for a future multicentric prospective study.
Methods and Materials: A CB with severe stenosis at B-mode and Doppler US was enrolled. HiFR-VF provided the 2D velocity vectors from multidirectional plane waves and allowed the quantification of the complex flows and wall shear stress (WSS) measurements at different locations. The 3D model of the diseased vessel was reconstructed starting from a 3D FFE MRI multi-chunk sequence that makes use of the inflow effects of blood to visualize vessels. Subsequently, CFD simulation of the CB was performed and the flow field was characterized using velocity streamlines, while reciprocating disturbed flow was described using the oscillatory shear index. HiFR-VF and CFD findings were compared to analyze the ability of HiFR-VF in identifying areas of vascular wall exposed to oscillatory WSS.
Results: WSS findings with HiFR-VF showed good agreement with the CFD simulation results. In particular, the areas of abnormal WSS obtained with the two modalities, matched.
Conclusion: Although WSS can only be estimated in a 2D plane with HiFR-VF, nonetheless oscillating WSS can be detected and correlate with the CFD results. Preliminary findings show that the study protocol was correctly designed and can be used for prospective clinical investigation.
Purpose: To establish the correlation between CIMT and TIA and the correlation between the quantitative and qualitative characteristics of the plaque in the wall of the carotid arteries and the occurrence and type of TIA.
Methods and Materials: 120 patients with TIA were tested by duplex ultrasonography and compared to the control group (n=25) compatible in age and gender. Among the ultrasonic parameters, the following ones were examined: CIMT, the presence and size of the plaque, and the presence of ulceration on the free surface of the plaque. Group of patients with TIA was divided into subgroups based on aetiopathological mechanism (emboligenic, haemodynamic and coagulopathy). The Student's t test and Pearson χ2 test were used for statistical analysis.
Results: Statistically, CIMT was significantly higher (p<0.05) among the patients with haemodynamic and emboligenic TIA in comparison with the control group. The frequency of the plaque larger than 70% was statistically significantly higher (p<0.01) among the patients with emboligenic and haemodynamic TIA in comparison with the control group. Regarding the frequency of ulceration, the difference between the group of patients with emboligenic TIA and the control group was highly statistically significant (p<0.01).
Conclusion: CIMT and the size of the plaque (larger than 70%) correlate with the occurrence of haemodynamic and emboligenic TIA. The presence of ulceration on the free surface of the plaque correlates with the occurrence of emboligenic TIA. Early diagnosis of carotid artery disease is of paramount importance from the aspect of stroke prevention, and ultrasound plays a pivotal role therein.
Purpose: To evaluate and compare manual and semiautomatic carotid intima-media thickness (CIMT) assessment.
Methods and Materials: Ultrasound B-mode images of 200 consecutive patients who underwent color-Doppler of supra-aortic trunks with RS80A Prestige, Samsung Healthcare from 5/2017 to 12/2017 were retrospectively evaluated. For each patient, CIMT was measured on the same image of the right common carotid artery, selected by an experienced (≥5 years) radiologist. Two different readers performed all measurements using both the manual and the semiautomatic method, randomly ordered sessions, separated by at least one week, the least experienced reader (2 years) repeating all measurements 4 weeks apart. Images were graded for quality by considering the quality index (QI), ranging from 0.00 to 1.00 automatically provided by the software.
Results: When all 200 cases were included, inter-reader reproducibility was significantly higher (p=0.010) for manual CIMT (bias=81%,-0.017 mm, coefficient of reproducibility(CoR)=0.143 mm) than semiautomatic CIMT (bias=75%,-0.001 mm,CoR 0.170=mm), while intra-reader reproducibility did not differ significantly(p=0.847). When only cases with IQ ≥0.75 were considered (n=158), inter-reader reproducibility was significantly higher (p=0.006 for semiautomatic CIMT (bias=86%,0.001 mm,CoR=0.092 mm) than manual CIMT, while intra-reader reproducibility was not significantly different (p=0.772). Concordance between semiautomatic and manual CIMT was fair (κ=0.341) with an agreement of 80% on the whole sample, and fair (κ=0.341) with an agreement of 80% in cases with IQ ≥0.75.
Conclusion: To achieve the best accuracy of semiautomatic CIMT, high quality index should be sought. Nevertheless, semiautomatic CIMT assessment with AutoIMT cannot yet substitute manual calculations in the attribution of cardiovascular risk.
Purpose: Intima media thickness (IMT) is a measure of atherosclerotic burden in diabetes mellitus (DM), and measurement of carotid IMT has been used as a surrogate for atherosclerosis in less accessible coronary and cerebral arterial systems. We aimed to compare carotid intima-media thickness (CIMT) in type 2 diabetics with controls and correlate CIMT with age, sex, BMI and duration of disease.
Methods and Materials: This was a cross-sectional study of 350 Type 2 diabetics and 350 controls recruited by systematic sampling between February 2015 to June 2016 in Port-Harcourt, Nigeria. CIMT was measured by ultrasound 1cm proximal to the carotid bulb and data was analyzed using statistical package for social sciences (SPSS) version 20, at significance level of p<0.05.
Results: Type 2 diabetics had significantly higher CIMT than non-diabetics (1.09±0.25mm vs 0.94±0.24mm, p =0.001). There was significant correlation between CIMT and age in type 2 diabetics (r=0.53, p=0.001), controls (r=0.76, p=0.001), and with duration of DM (r=0.194, p=0.001). Negative correlation between CIMT and BMI in the type 2 diabetic participants (r= -0.913, p=0.001) was observed. CIMT was significantly higher in male compared to female diabetics (p=0.001). There was no significant difference in the prevalence of carotid plaques between type 2 diabetics and non-diabetics (22.8% vs 19.4%; p=0.32) or between left and right carotid arteries.
Conclusion: CIMT was greater in diabetics compared with controls, and correlated with age in both groups. CIMT may be used as a measure of atherosclerotic disease in our environment.
Purpose: Obesity increases the burden of atherosclerosis and, therefore, represents a risk factor for clinical cardiovascular disease. Intima media thickness (IMT) is a noninvasive marker of subclinical atherosclerosis. It remains unclear whether weight loss in obese subjects is accompanied by a reduction in consistent with a lowering of risk of cardiovascular events. We evaluated the effects of bariatric surgery and of a conservative approach (diet and exercise) on carotid IMT and cardiovascular risk factors in obese subjects.
Methods and Materials: We studied 163 individuals [a control group of 75 healthy participants (40 women, age 42 years (31-51), body mass index (BMI) 24.33 (22.23-27.2)) and 88 obese subjects (52 women, age 46 (38-52), BMI 43.37 (40.18-47))]; 22 (25%) obese subjects underwent bariatric surgery. We recorded weight, BMI, blood pressure, cholesterol, triglycerides, fasting glucose, insulin, and insulin resistance index and calculated Framingham Risk Scores (FRS). Carotid IMT was evaluated by ultrasound. The impact of weight loss on carotid IMT at 2-year follow-up was evaluated with regression models.
Results: At 2-year follow-up after bariatric surgery, BMI had decreased from 45.45 to 27.75 kg/m2 (p<0.001) and FRS decreased from 15 (10-16) to 13 (8-15) (p=0.035). Mean carotid IMT decreased from 0.85 ± 0.13 mm to 0.65 ± 0.05 mm (p<0.001), a reduction of 0.005 mm per kg of weight lost. Conservative approach did not impact cardiovascular risk markers.
Conclusion: Weight loss after bariatric surgery substantially reduces carotid IMT values consistent with a lowering in risk of cardiovascular events.