Echo-tracking technology assessment of carotid artery stiffness in patients with coronary slow flow

Automated measurement of compression-decompression in arterial diameter and wall thickness by image-free ultrasound

BACKGROUND AND OBJECTIVE

The manual measurement of arterial diameter and wall thickness using imaging modalities demand expertise, and the state-of-art automated or semi-automated measurement features are seldom available in the entry-level systems. The advanced ultrasound modalities are expensive, non-scalable, and less favorable for field and resource-constrained settings. In this work, we present a novel method to measure arterial diameter (D), surrogate intima-media thickness (sIMT), and with them their intra-cardiac cycle changes by employing an affordable image-free ultrasound technology.

METHODS

The functionality of the method was systematically validated on a simulation testbed, phantoms and, 40 human subjects. The accuracy, agreement, inter-beat, and inter-operator variabilities were quantified. The in-vivo measurement performance of the method was compared against two reference B-mode tools - Carotid Studio and CAROLAB.

RESULTS

Simulations revealed that for the A-mode frames with SNR > 10 dB, the proposed method identifies the desired arterial wall interfaces with an RMSE < 20 μm. The RMSE for the diameter and wall thickness measurements from the static phantom were 111 μm and 14 μm, and for the dynamic phantom were 117 μm and 18 μm, respectively. Strong agreement was seen between the in-vivo measurements of the proposed method and the two reference tools. The mean absolute errors against the two references and the inter-beat variability were smaller than 0.18 mm for D and smaller than 36 μm for sIMT measurements. Likewise, the respective inter-observer variabilities were 0.16 ± 0.23 mm and 43 ± 25 μm.

CONCLUSION

Acceptable accuracy and repeatability were observed during the validation, that were on a par with the recently reported B-mode techniques in the literature. The technology being real-time, automated, and relatively inexpensive, is promising for field and low-resource settings.

ARTSENS® Pen-portable easy-to-use device for carotid stiffness measurement: technology validation and clinical-utility assessment

OBJECTIVE

The conventional medical imaging modalities used for arterial stiffness measurement are non-scalable and unviable for field-level vascular screening. The need for an affordable, easy-to-operate automated non-invasive technologies remains unmet. To address this need, we present a portable image-free ultrasound device-ARTSENS^® Pen, that uses a single-element ultrasound transducer for carotid stiffness evaluation.

APPROACH

The performance of the device was clinically validated on a cohort of 523 subjects. A clinical-grade B-mode ultrasound imaging system (ALOKA eTracking) was used as the reference. Carotid stiffness measurements were taken using the ARTSENS^® Pen in sitting posture emulating field scenarios.

MAIN RESULTS

A statistically significant correlation (r > 0.80, p < 0.0001) with a non-significant bias was observed between the measurements obtained from the two devices. The ARTSENS^® Pen device could perform highly repeatable measurements (with variation smaller than 10%) on a relatively larger percentage of the population when compared to the ALOKA system. The study results also revealed the sensitivity of ARTSENS^® Pen to detect changes in arterial stiffness with age.

SIGNIFICANCE

The easy-to-use technology and the automated algorithms of the ARTSENS^® Pen make it suitable for cardiovascular risk assessment in resource-constrained settings.

Evaluation of ultrasonography on carotid arteries and left ventricular function in patients with subclinical atherosclerosis

Ultrasonography in the evaluation and diagnosis of carotid arteries and left ventricular function in patients with subclinical atherosclerosis (SA) was explored. In total, 152 patients with no obvious clinical symptoms of atherosclerosis confirmed by carotid ultrasonography in Tengzhou Central People's Hospital from September 2015 to March 2016 were enrolled as the experimental group, and further 45 patients with normal physical examination at the same time were collected as the control group. Patients in the experimental group were divided into three groups according to Framingham risk assessment: low, middle and high risk. The carotid arteries and left ventricular function of all patients were detected by Doppler ultrasound. There were differences in the systolic pressure, TG and TC between the control group and the experimental group (P<0.05). The expression levels of β, cIMT, Ep and PWVβ increased with the risk degree in the low, middle and high risk groups (P<0.05). The expression levels of LVEDV, LVESV, and LVEF in the experimental group were significantly decreased compared with those in the control group (P<0.05), while the expression levels of LAV, E/e, GLS and GCS were significantly increased compared with those in the control group (P<0.05). There was a difference of left ventricular function parameters in the low, medium and high risk groups (P<0.05). The expression levels of LVEDV, LVESV, LAV and E/e increased with the risk degree in the low, middle and high risk groups (P<0.05). The detection rate of plaque was lower in the low risk group than those in the middle and high risk group (P<0.05). By observing the parameters of carotid arteries and left ventricular function, it was found that ultrasonography has important clinical value in the early diagnosis of SA, and can be promoted in clinic.

Carotid arterial wall stiffness correlates positively with impedance of the umbilical and uterine arteries in women with preeclampsia

PURPOSE

This study aimed to determine whether the stiffness of the arterial walls of women with preeclampsia (PE) differs from that of healthy controls and to evaluate its association with fetal and uterine artery Doppler variables and perinatal outcomes in PE.

METHODS

We enrolled 30 women with PE and 30 normotensive pregnant women. Carotid artery stiffness and Doppler variables of the uterine, umbilical, and fetal middle cerebral arteries and the ductus venosus were measured in both groups. Measurements of the common carotid artery were performed by the Aloka ultrasonic echo-tracking technique.

RESULTS

Stiffness of the carotid artery wall of women with PE was significantly higher than that of healthy controls. It was positively correlated with the pulsatility index of the uterine and umbilical arteries and negatively correlated with the cerebroplacental ratio in women with PE. In women with PE, the carotid artery augmentation index showed negative correlations with birth weight and Apgar score.

CONCLUSIONS

The stiffness of the carotid arteries of women with PE is increased, and this increase is positively correlated with the impedance of the umbilical and uterine arteries.

Comparison of arterial stiffness/compliance in the ascending aorta and common carotid artery in healthy subjects and its impact on left ventricular structure and function

Arterial stiffness and compliance parameters from two adjacent elastic arteries [aorta and common carotid artery (CCA)] were compared and their relationship with left ventricular (LV) structure and function and clinical parameters was assessed. 584 healthy subjects were prospectively enrolled [mean age 47.8 ± 18.4 years, range 16-94; 318 (54.4%) men]. They underwent comprehensive transthoracic echocardiography; M-mode diameters were measured at the level of the ascending aorta in systole and diastole and by echo-tracking at the level of the left CCA. The β-stiffness, pressure-strain elastic modulus, arterial compliance and one-point pulse wave velocity were derived. A significant correlation was observed between aortic and CCA stiffness and compliance parameters (p < 0.0001 for all). At multiple regression analysis, CCA stiffness parameters were constantly correlated with age and systolic blood pressure, and accounted for up to 56% of the variability (vs. only 29% in aortic stiffness and compliance). CCA stiffness parameters were found to better predict LV structure, diastolic function than aortic stiffness parameters. Aortic and CCA stiffness and compliance were found to correlate with each other and with age, with the correlation being higher for CCA stiffness. At multiple regression analysis, CCA stiffness parameters were better predictors of LV structure and function than aortic stiffness.