Variability of automated carotid intima‐media thickness measurements by novice operators

Carotid intima‐media thickness (C‐IMT) measurements provide a non‐invasive assessment of subclinical atherosclerosis. The aim of the study was to assess the inter‐ and intra‐observer variability of automated C‐IMT measurements undertaken by two novice operators using the Panasonic CardioHealth Station. Participants were free from cardio‐metabolic disease, and each underwent serial bilateral C‐IMT ultrasound measurements. Immediate interoperator measurement variability was calculated by comparing initial measurements taken by two operators. Immediate retest variability was calculated from two consecutive measurements and longer term variability was assessed by conducting a further scan 1 week later. Fifty apparently healthy participants (n = 20 females), aged 26·2 ± 5·0 years, were recruited. Operator 1 recorded a median (interquartile range) right and left‐sided C‐IMT of 0·471 mm (0·072 mm) and 0·462 mm (0·047 mm). Female's right and left C‐IMT were 0·442 mm (0·049 mm) and 0·451 mm (0·063 mm), respectively. The limits of agreement (LoA) for immediate interoperator variability were ?0·063 to 0·056 mm (mean bias ?0·003 mm). Operator 1's immediate retest intra‐operator LoA were ?0·057 to 0·046 mm (mean bias was ?0·005 mm). One‐week LoA were ?0·057 to 0·050 mm (mean bias ?0·003 mm). Operator 2 recorded median right and left‐sided C‐IMT of 0·467 mm (0·089 mm) and 0·458 mm (0·046 mm) for males, respectively, whilst female measurements were 0·441 mm (0·052 mm) and 0·444 mm (0·054 mm), respectively. Operator 2's intra‐operator immediate retest LoA were ?0·056 to 0·056 (mean bias 相似文献   

超声检测颈动脉内-中膜厚度的重复性评价

目的 评价"十一五"国家科技支撑计划<冠心病早期诊断和综合治疗技术体系的研究>之动脉粥样硬化性疾病临床前病变队列研究中,超声检测颈动脉内-中膜厚度(intima-media thickness,IMT)的重复性,论证其作为主要研究指标的可靠性.方法 抽取10例受检者,分别使用不同超声仪各检查次,评价仪器间IMT检测重复性;2个中心各抽取2名超声医生,分别独立对共15例受检者进行重复检查,评价检查者自身及检查者间重复性;抽取20份图像,同一阅读者重复阅读2次,参考阅读者阅读1次,评价阅读者自身及阅读者间重复性.所有图像均行中心阅读测量.结果 平均IMT的测量均差(meandifference,MD)在仪器间、检查者自身间、不同检查者间、测量者自身间、不同测量者间分别为(0.028±0.017)mm、(0.048±0.052)mm、(0.035±0.022)mm、(0.030±0.032)mm、(0.081±0.043)mm;最大IMT的上述测值依次为(0.047±0.029)mm、(0.090±0.09)mm、(0.055±0.044)mm、(0.062±0.053)mm、(0.085±0.050)mm.结论 平均IMT测量重复性优于最大IMT,且测量点越多,重复性越佳.与国外资料相比,本课题颈动脉超声测量IMT重复性良好.     

The echogenicity of the intima–media complex in the common carotid artery is related to insulin resistance measured by the hyperinsulinemic clamp in elderly men

The echogenicity of the intima–media complex (IM‐GSM) has recently been shown to be related to the echogenicity in carotid artery plaque and to predict cardiovascular (CV) mortality. The present study aims to evaluate the relationship between metabolic CV risk factors, with special emphasis on insulin resistance, and IM‐GSM in the carotid artery. Carotid artery ultrasound with grey‐scale median analysis of the intima–media complex, IM‐GSM, was performed in a population sample of 480 men aged 75 years. In these subjects, a euglycemic hyperinsulinemic clamp to investigate insulin resistance was performed together with measurements of conventional CV risk factors at the age of 70. The metabolic syndrome (MetS) was defined by the NCEP/ATPIII‐criteria. In univariate analysis, IM‐GSM in the common carotid artery was inversely correlated with the intima–media thickness (IMT), body mass index (BMI), waist/hip ratio, fasting glucose, serum triglycerides, low HDL cholesterol and insulin resistance at the clamp (r = ?0·24, P<0·001). In multiple regression analysis, only insulin resistance at the clamp and BMI were independently related to IM‐GSM. Subjects with the MetS (22%) showed a reduced IM‐GSM when compared to those without (64 ± 20 SD versus 68 ± 19, P<0·05). Because the echogenicity of the intima–media complex in the carotid artery is related to obesity and insulin resistance at clamp independently of IMT, this new vascular characteristic would serve as a marker of vascular alterations induced by insulin resistance and the MetS and has the advantage to be obtainable in almost all subjects.     

Brachial artery hyperemic blood flow velocities are related to carotid atherosclerosis

Objective: Cardiovascular (CV) risk relates to the blood flow velocity pattern in the brachial artery during hyperemia, especially to the hyperaemic systolic to diastolic mean blood flow velocity (SDFV) ratio. Here, we investigated the relations between SDFV in the brachial artery and different characteristics of carotid atherosclerosis. Material and methods: Data were collected from 1016 70‐year‐olds participating in the Prospective Investigation of Uppsala Seniors study. Doppler recordings of blood flow velocity during hyperemia were analysed in the brachial artery. In the carotid artery, intima‐media thickness (IMT) was recorded together with an assessment of echogenicity by the Grey scale median (GSM) method in both overt plaques and in the intima‐media complex (IM‐GSM). Results: The SDFV ratio was related to the number of carotid arteries affected by plaque (P = 0·018) and inversely to plaque echogenicity (P = 0·0003). The SDFV ratio was also related to IMT (P = 0·0022) and inversely to IM‐GSM (P = 0·0001). These relations were statistically significant also after adjusting for major CV risk factors, individually as well as summarised as the Framingham risk score. Conclusion: Our results indicate that the hyperemic systolic to diastolic blood flow velocity ratio in the brachial artery is related to atherosclerosis in the carotid artery.     

Conventional treatment after myocardial infarction in routine clinical practice results in regression of left common carotid intima‐media thickness

This study aimed to evaluate the effect of standard medical treatment on the progression of atherosclerosis after a myocardial infarction, in an ordinary clinical setting, by measuring the right and left common carotid intima‐media thickness (IMT). The first investigation took place 3–12 months after the index event; the second took place 3·3–8·2 years after the first. In both investigations, the right and left carotid arteries of 102 patients were examined with an ultrasound duplex scanner. Common carotid IMT and calculated cross‐sectional intima‐media area (cIMa) were measured on both sides. More than 90% of the patients were treated with aspirin, beta‐blockers and statins. In the first investigation, IMT and cIMa were significantly greater on the left side compared to the right (IMT: 0·83 ± 0·22 and 0·74 ± 0·18 mm, P<0·001; cIMa: 18·2 ± 5·2 and 16·3 ± 5·1 mm², P<0·001). In the second investigation, IMT on the left side was significantly reduced compared to the first investigation (0·79 ± 0·22 and 0·83 ± 0·22 mm, P<0·05) with a corresponding tendency towards a decrease in cIMa on the same side. In our study, conventional medical treatment after a myocardial infarction in ordinary clinical routines resulted in regression of the common carotid IMT on the left side. The significant side difference in IMT emphasizes the importance of where and how the carotid IMT is measured in studies using this surrogate end point.     

How can the variability in ultrasound measurement of intima-media thickness be reduced? Studies of interobserver variability in carotid and femoral arteries

A critical component in scientific studies of most biological variables is the variation or error in measurements which leads to non-identical results of repeated measurements from the same subject. The aim of this study was to investigate whether the interobserver error (s) in measurement of intima-media thickness (IMT) in carotid and femoral arteries could be decreased if the mean value obtained using two ultrasound images from each of the right and left arteries was used in the analyses instead of the mean value obtained using images from only the right artery. In addition, we wished to evaluate two different reading procedures, one based on manual tracing of echo interfaces and the other on automated edge detection. In a methodological study, 50 subjects were examined with ultrasound twice in the same day by two independent laboratory technologists. The ultrasound images were analysed in two ways: using a computerized manual tracing analysing system and an automated analysing system. When both right and left carotid arteries were examined (manual reading), the interobserver error was smaller than that determined for the examination of only the right artery, for IMT_mean in both the common carotid artery (P = 0·06) and the carotid artery bulb (P<0·05). The interobserver error was also significantly smaller for double-sided vs. one-sided examination with automated reading of IMT_mean in the common carotid artery (P<0·01) and in the carotid artery bulb (P<0·01). The coefficient of variation (CV) for measurement in the common carotid artery decreased from 8·6% (one-sided, manual reading) to 5·3% (double-sided, automated reading). The interobserver error in measurement of IMT in the common femoral artery did not improve by examination of both right and left arteries. The results from this study show that the interobserver errors in measurement of IMT can be decreased by using ultrasound images from both the right and the left carotid arteries, and that the use of an automated analysing system greatly simplifies the reading of ultrasound images with sustained low variability.     

Evaluation of intima-media thickness and vascular elasticity of the common carotid artery in patients with isolated systolic hypertension using ultrasound radiofrequency-data technology

Background: Radiofrequency (RF) data technology is a newly developed method to evaluate vascular disease, especially subclinical atherosclerotic change. Data regarding predictors of intima‐media thickness (IMT) and vascular elasticity of the common carotid artery (CCA) in subjects with isolated systolic hypertension (ISH) using ultrasound RF‐data technology are scarce. Aims: We evaluated the change in IMT and vascular elasticity of the CCA in patients with ISH at an early phase using US RF‐data technology. Methods: Thirty‐nine patients with ISH and 41 age‐matched control subjects were the study population. The common carotid arterial systolic diameter (Ds), diastolic diameter (Dd), IMT, carotid distensibility (CD), local pulse wave velocity (PWVβ) and stiffness (β) were compared between the two groups, as were correlations between pulse pressure (PP) and parameters of vascular stiffness. Results: Common carotid arterial Ds, Dd, IMT, PWVβ and β increased whereas CD decreased more significantly in the ISH group than in age‐matched controls. The level of PP in the ISH group had significant positive correlations with PWVβ (r = 0·298, P<0·05) and β (r = 0·291, P<0·05), whereas significant correlations with CD were not observed. Conclusions: US RF‐data technology could be used to accurately and quantitatively evaluate increased IMT and decreased arterial elasticity of the CCA in patients with ISH compared with normal subjects.     

Is there an underestimation of intima‐media thickness based on M‐mode ultrasound technique in the abdominal aorta?

Measuring intima-media thickness (IMT) in the common carotid artery (CCA) is a valuable resource for the evaluation of subclinical atherosclerosis. The main objective of this study was to explore whether a B-mode ultrasound technique, Philips ATL, and an M-mode ultrasound technique, Wall Track System (WTS), show interchangeable results when measured in CCA and the abdominal aorta (AA). A total of 24 healthy, young subjects were examined. IMT and lumen diameter (LD) of the AA and the CCA were measured twice by two skilled ultrasonographers with two different ultrasound equipment B-mode: (Philips, ATL and M-mode: WTS).The intra-observer variability of IMT in CCA and AA using B-mode showed a coefficient of variation 8% and 9%, and with M-mode 11% and 15%, respectively. Interobserver variability of IMT in CCA and AA using B-mode was 6% and 12%, and with M-mode 11% and 18%, respectively. CCA IMT was 0·53 ± 0·07 and 0·53 ± 0·09 mm using B-mode and M-mode, respectively. However, in AA, IMT was 0·61 ± 0·05 and 0·54 ± 0·10 mm using B-mode and M-mode, respectively. Thus, AA IMT was 11·5% thicker using B-mode (P < 0·01). We received adequate IMT readings from the carotid artery as well as the AA using two commonly used B-mode and M-mode techniques. B-mode technique seems to show less variability, especially in the AA. More importantly, the two techniques measured different IMT thickness in the aorta, emphasizing the importance of using similar technique when comparing the impact of absolute values of IMT on cardiovascular disease.     

Associations of Carotid Artery Intima‐Media Thickness (IMT) With Risk Factors and Prevalent Cardiovascular Disease

Objective. The goal of this study was to compare internal carotid artery (ICA) intima‐media thickness (IMT) with common carotid artery (CCA) IMT as global markers of cardiovascular disease (CVD). Methods. Cross‐sectional measurements of the mean CCA IMT and maximum ICA IMT were made on ultrasound images acquired from the Framingham Offspring cohort (n = 3316; mean age, 58 years; 52.7% women). Linear regression models were used to study the associations of the Framingham risk factors with CCA and ICA IMT. Multivariate logistic regression models and receiver operating characteristic (ROC) curve analysis were used to compare the associations of prevalent CVD with CCA and ICA IMT and determine sensitivity and specificity. Results. The association between age and the mean CCA IMT corresponded to an increase of 0.007 mm/y; the increase was 0.037 mm/y for the ICA IMT. Framingham risk factors accounted for 28.6% and 27.5% of the variability in the CCA and ICA IMT, respectively. Age and gender contributed 23.5% to the variability of the CCA IMT and 22.5% to that of the ICA IMT, with the next most important factor being systolic blood pressure (1.9%) for the CCA IMT and smoking (1.6%) for the ICA IMT. The CCA IMT and ICA IMT were statistically significant predictors of prevalent CVD, with the ICA IMT having a larger area under the ROC curve (0.756 versus 0.695). Conclusions. Associations of risk factors with CCA and ICA IMT are slightly different, and both are independently associated with prevalent CVD. Their value for predicting incident cardiovascular events needs to be compared in outcome studies.     

Long‐term changes in dynamic cerebral autoregulation: a 10 years follow up study

This study takes a novel approach to describing time‐related changes in dynamic cerebral autoregulation (dCA). It is well‐recognized that dCA exhibits both intra‐ and inter‐ subject variability, and this study seeks to characterize the extent to which intra‐subject variability occurs after a significant period of time by studying the same subjects 10 years apart, thus eliminating inter‐subject variability as a source of error. Ten healthy subjects were identified in 1998 and followed up in 2008. On each visit they underwent simultaneous recordings of right middle cerebral artery cerebral blood flow velocity (RMCA CBFV), blood pressure and heart rate. Data were analysed in the frequency domain using transfer function analysis and in the time domain using CBFV step response, from which the autoregulatory index (ARI) was calculated. Ten subjects of mean age 35·5 (range 24–51) years in 1998 (seven male) were studied. There was a significant fall in ARI from 1998–2008 (ΔARI = 1·1, P = 0·021), along with a significant rise in coherence in 2008 (at 0·05 Hz, P = 0·018). Difference in mean step response between 1998 and 2008 was also significant (P = 0·045). This is the first study to assess dCA in the same subjects 10 years apart, providing a novel opportunity to assess intra‐subject variation in dCA after a long time period has elapsed. A fall in frequency and time domain parameters was observed. This is important, and needs to be considered in future studies assessing long‐term changes in dCA, particularly given the body evidence which suggests that dCA is unaffected by ageing.     

Predictors of the intima‐media thickness of carotid artery in asymptomatic newly detected severe hypercholesterolemic patients

Background: Data about predictors of intima‐media thickness (IMT) of common carotid artery (CCA) in asymptomatic subjects with newly detected severe hypercholesterolemia is scarce. Aim: This research is aimed at studying the predictors of the IMT of CCA among basic atherogenic risk biomarkers – lipid [total cholesterol (TC), triglycerides, high‐density lipoprotein cholesterol, low‐density lipoprotein (LDL) cholesterol, Apolipoprotein‐B, Apolipoprotein‐Ai, Apolipoprotein‐B/A₁ index] and non‐lipid, [asymmetric dimethylarginine (ADMA), total homocysteine, cell adhesion molecules] in asymptomatic subjects with newly detected severe hypercholesterolemia. Methods: Two hundred and fifty asymptomatic patients with severe, newly hypercholesterolemia and 200 controls were evaluated. Hypercholesterolemia was defined as TC > 7·5 mm and LDL cholesterol > 4·9 mm . The ADMA and cell adhesion molecules were determined by ELISA and total homocysteine by high‐performance liquid chromatography. Results: There was significant difference between the two groups in respect to all lipid biomarkers (P<0·001). Hypercholesterolemic patients had significantly higher level of ADMA, sVCAM‐1, sICAM‐1, IMT (P<0·001), whereas no significant difference was found between two groups with respect to total homocysteine, P‐selectin and E‐selectin (P>0·05). A strong positive correlation between IMT mean and age (r_xy = 0·714; P<0·001), Apolipoprotein‐B (r_xy = 0·706; r_xy < 0·001), Apolipoprotein‐B/A₁ (r_xy = 0·324; P<0·001), ADMA (r_xy = 0·603; P<0·001) was found. The subsequent linear and multiple regression analysis selected age and Apolipoprotein‐B as most significant factors in relation to IMT mean. Apolipoprotein‐B is a better factor for assessment of risk, as LDL cholesterol underestimates the risk in asymptomatic subjects with newly detected severe hypercholesterolemia, until more rapid and feasible methods for measurement of small and dense LDL are available.     

Ultrasound measurements of carotid intima–media thickness by two semi‐automated analysis systems

Increased carotid intima–media thickness (cIMT) is associated with an increased risk of cardiac events and stroke. Several semi‐automated edge‐detection techniques for measuring cIMT are used for research and in clinical practice. Our aim was to compare two currently available semi‐automated techniques for the measurement of cIMT. Carotid ultrasound recordings were obtained from 99 subjects (mean age 54·4 ± 8·9 years, range 33–69) without known cardiovascular diseases using a General Electric (GE) Vivid 7 ultrasound scanner, 8‐MHz transducer. The far‐wall cIMT was evaluated 1–2 cm proximal to the carotid bulb. Three diastolic images (ECG R‐wave) from the left and three images from the right common carotid arteries were analysed using GE and Artery Measurement System (AMS) semi‐automated softwares. Mean systolic and diastolic blood pressures were 120 ± 13 and 76 ± 8 mmHg, respectively. The cIMT_mean (left + right)/2 by GE and cIMT_mean (left + right)/2 AMS were highly correlated (r = 0·92, P<0·001). Higher values were measured by GE (0·72 ± 0·12 mm) compared with AMS (0·69 ± 0·12 mm), and this was significant (P<0·001). The coefficients of variation for the intra‐observer variability of cIMT_mean (left + right)/2 were 1·0% (GE) and 2·2% (AMS). cIMT_mean measured by GE's semi‐automated edge‐detection method correlated well with that measured by AMS. However, there were small but significant systematic differences between the cIMT_mean values measured by the two techniques. Thus, the use of only one type of measurement program seems favourable in follow‐up studies and when evaluating treatment effects.     

Common carotid artery intima-media thickness determinants in a population study.

OBJECTIVE: Common carotid artery (CCA) intima-media thickness (IMT) is considered an atherosclerosis risk marker. Thickening of the intima-media complex is accelerated by vascular risk factors, in particular, by age and elevated blood pressure. Nonetheless, it also reflects intimal hyperplasia and intimal fibrocellular hypertrophy provoked by nonatherosclerotic mechanisms such as tensile wall stress. The aims of our study were to investigate the relationship between CCA IMT and the presence of vascular risk factors and to correlate CCA IMT with the degree of distal internal carotid artery (ICA) stenosis and the proximal CCA resistive index (RI), representative of wall stress. METHODS: We assessed CCA IMT, the CCA RI, and the presence of carotid plaques in 1655 consecutive patients. Demographic features and vascular risk factors were collected. RESULTS: A positive linear relationship between mean IMT and age was observed (R(2) = 0.27; P < .001). In the multiple stepwise regression model, the presence of ICA plaques and vascular risk factors were all independently associated with higher IMT. When considering IMT values for left and right sides separately, there was an independent relationship between CCA IMT and the lateralized percentage of ICA stenosis (right IMT-right ICA percentage, R(2) = 0.10; P < .0001; left IMT-left ICA percentage, R(2) = 0.16; P < .0001) and the CCA RI, even after correcting for age and vascular risk factors. CONCLUSIONS: Risk factors for atherosclerosis and the percentage of ICA stenosis were independently associated with higher IMT values and an increase in the RI. The synergic action of risk factors may cause further deterioration of mechanical forces independent of carotid atherosclerosis.     

Reduced common carotid artery longitudinal wall motion and intramural shear strain in individuals with elevated cardiovascular disease risk using speckle tracking

Longitudinal motion of the intima–media and adventitia layers of the common carotid artery (CCA) wall were assessed with ultrasound speckle tracking in seven individuals with spinal cord injury (SCI), who are considered at increased risk of cardiovascular disease, and in seven able-bodied participants. CCA longitudinal wall displacement and intramural shear strain were compared to traditional markers of arterial health, including CCA stiffness and intima–media thickness (IMT). For each cardiac cycle, longitudinal CCA wall motion was characterized by bidirectional movement patterns containing motion retrograde to blood flow during systole, followed by antegrade motion during diastole. Relative displacement of the intima–media versus the adventitia was used to calculate longitudinal intramural shear strain and provided insight to local arterial wall properties. The retrograde intramural shear strain was smaller in individuals with SCI by 60·2% (P<0·05) compared to able-bodied participants, showing smaller peak displacements in both the intima–media (P<0·05) and adventitia (P<0·05). In the antegrade direction, there were no group differences in either longitudinal displacements or shear strain. The group differences observed in the retrograde wall motion phase were greater than those observed for CCA stiffness or IMT and were found to be independent of both indices, indicating indices of the retrograde phase intramural shear strain may be a novel and sensitive marker of vascular health. Our findings demonstrate that assessment of longitudinal arterial wall shear strain may provide valuable insight into vascular structure and function and may hold potential for the early detection of cardiovascular disease.     

Influence of arterial wave reflection on carotid blood pressure and intima‐media thickness in older endurance trained men and women with pre‐hypertension

Increased carotid intima‐media thickness (IMT) with aging is a significant predictor of mortality. Older endurance trained (ET) individuals have lower carotid artery stiffness but similar carotid IMT when compared to sedentary (SED) age‐matched peers. The purpose of this study was to examine the contribution of arterial wave reflections to carotid hemodynamics and IMT in older ET and SED with pre‐hypertension. Subjects consisted of endurance‐trained master athletes and age‐matched sedentary controls (mean age 67 years). Carotid artery Beta‐stiffness index and IMT was assessed with ultrasonography. Carotid pressure and augmented pressure from wave reflections (obtained from pulse contour analysis) was measured with applanation tonometry. Carotid systolic blood pressure (SBP) and IMT were not different between groups (P>0·05). Carotid stiffness was significantly lower in ET versus SED (7·3 ± 0·8 versus 9·9 ± 0·6, P<0·05). Augmented pressure was significantly greater in ET versus SED (17·7 ± 1·6 versus 13·3 ± 1·5 mmHg, P<0·05). When adjusting for differences in resting heart rate, there were no group differences in augmented pressure. In conclusion, older ET persons with pre‐hypertension have reduced carotid artery stiffness, but similar carotid SBP and carotid IMT when compared to SED. The lack of change in carotid SBP and IMT in older ET may be related to the inability of chronic exercise training to reduce bradycardia‐related augmented pressure from wave reflections with aging.     

Fully Automated Dual‐Snake Formulation for Carotid Intima‐Media Thickness Measurement

Automated computer‐aided detection systems for measurement of the carotid intima‐media thickness (IMT) are becoming popular. These systems yield lumen‐intima (LI) and media‐adventitia (MA) borders. In this work, we developed and validated a novel and patented completely automated IMT measurement system called carotid measurement using dual snakes (CMUDS): a class of AtheroEdge system (Global Biomedical Technologies, Inc, Roseville, CA). CMUDS is modeled as a dual parametric system corresponding to LI and MA borders with initialization from the far adventitia layer. The novelty of CMUDS is the first‐order absolute moment–based external energy, which provides stable deformation. The dual snakes evolve simultaneously and are forced to maintain a regularized distance to prevent collapsing or bleeding. Two independent readers manually traced the LI/MA boundaries of a multi‐institutional, multi‐ethnic, and multi‐scanner database of 665 longitudinal images for performance evaluation. CMUDS was also benchmarked against a previously developed automated technique. CMUDS correctly processed 660 images (99.2% success). The differences between the CMUDS and two manual IMT measurements (mean ± SD) were 0.013 ± 0.216 and ?0.021 ± 0.197 mm, respectively. The corresponding figures of merit for CMUDS compared to reader tracings were 98.4% and 97.5%. Compared to the previous technique (IMT differences, 0.022 ± 0.276 and ?0.012 ± 0.266 mm), CMUDS improved accuracy (Wilcoxon P < 0.009) and variability (Fisher P < 10^?8). Among different resolution images from original equipment manufacturer ultrasound scanners, CMUDS performed best with high‐resolution images corresponding to 0.0789 mm/pixel. Accuracy in IMT measurement with the proposed automated CMUDS technique makes this system adaptable to large multi‐center studies, in which such an IMT measurement system would be very useful tool.     

A methodological study of arterial wall function using ultrasound technique

We aimed to establish reference values for three important properties of the arterial wall using a conventional ultrasound scanner. We measured: (1) intima–media thickness (IMT) of the carotid arteries with the internal trace function of the ultrasound system; (2) wall stiffness by pulsatile diameter changes in the right common carotid artery assessed by M-mode; and (3) endothelial function expressed as flow-mediated dilatation (FMD) of the brachial artery. IMT and wall stiffness measurements and reproducibility were compared with those obtained by external analysing systems. All variables were obtained in healthy subjects (n = 20), 29–53 years old. IMT increased with age (P<0·01). There was no difference in IMT between men and women. The inter-operator variability for measuring IMT was 6–9%. The same order of reproducibility was obtained with an external PC-based analysing system. Regarding wall stiffness, no correlation was found with age, nor any difference between men and women. A low intra-operator variability (CV < 10%) was found for measurements of wall stiffness with both M-mode and an external wall tracking system. FMD of the brachial artery diminished with age (P<0·01). There was a relation between FMD and brachial artery size (P<0·01) and, therefore, as men have larger arterial diameters (P<0·01), smaller FMD in men. We conclude that it is possible to characterize arterial wall function non-invasively in an adequately reproducible manner using a conventional ultrasound system in healthy middle-aged men and women.     

Carotid artery intima-media thickness and plaque score for the risk assessment of stroke subtypes

As measures for the severity of carotid atherosclerosis, we compared common carotid artery (CCA) intima-media thickness (IMT) and plaque score (PS) for risk assessment of respective stroke subtypes. The subjects comprised 792 nonstroke and 311 stroke patients, including 72 with atherothrombotic infarction (AI), 113 with lacunar infarction (LI), 54 with cardioembolic infarction and 29 with cerebral hemorrhage. IMT was bilaterally measured on CCA far walls, and averaged. PS was obtained by summing up the maximum thickness of all plaques in bilateral carotid arteries. Both IMT and PS were greater in AI and LI patients than in nonstroke patients (all p < 0.05), but similar between other subtype and nonstroke patients. By receiver operating characteristic (ROC) curve analyses, both measures discriminated the likelihood for AI and LI (all p < 0.05), but not for other subtypes. When discriminating AI, ROC area defined by PS (0.80) was greater than that defined by IMT (0.68) (p < 0.05). Thus, although both CCA IMT and PS appear to help for risk assessment of AI and LI, risk of AI may be more effectively assessed by PS.     

Reliability of Vertical Jump Performance evaluated with contact mat in elderly women

The aim of this study was to evaluate the reliability of the vertical jump (VJ) using a contact mat in elderly women. Thirty‐one physically active women aged 69·5 ± 5·6 years participated in this study. Jump performance was evaluated with a contact mat. The first testing session (s1) consisted of four countermovement jumps interspersed with 40 s rest intervals. After a period of 5–7 days, volunteers performed the second session (s2) utilizing the same procedures. The intersession statistical analysis was calculated considering the two highest jumps, one obtained in each section. The intra‐session analysis utilized all eight jumps, all four from each section, and the differences between means were calculated by repeated measures ANOVA. Reliability was tested using the intra‐class correlation coefficient (ICC) and agreement by the Bland–Altman method. The intra‐ and inter‐subject variation percentage was calculated by the coefficient of variation (CV). Results: The intersession results displayed a high ICC (0·91; P<0·001) and a good agreement verified by the Bland–Altman method. There was a significant difference in the intra‐session analysis only in s2 between the jumps 2 and 4. Both in s1 and s2, the ICC was high (0·96; P<0·001; 0·95; P<0·001), and the within session reliability CV was low (10·14% and 9·07%). Conclusion: In physically active elderly women, VJ evaluation using a contact mat is a reliable method and could be used to estimate jump height. Additionally, the results of this study could serve as reference values in similar samples evaluated with the same procedures.     

Glucose turnover and intima media thickness of internal carotid artery in type 2 diabetes offspring

Background First‐degree offspring (OFF) of type 2 diabetic (T2DM) patients bear a ~40% lifetime risk of developing T2DM. They are insulin resistant and carry a risk of premature atherosclerosis, the extent of which can be estimated by intima media thickness (IMT) of the carotid artery (CA). Thus, this study examines parameters of glucose and lipid metabolism, insulin sensitivity, beta cell function (BCF) and IMT with their interrelationships in middle‐aged OFF. Materials and methods T2DM‐OFF (n = 18, 14f/4m, 45·6 ± 2·1 years, BMI: 26 ± 1 kg m^?2) were compared with 18 matching humans without a family history of diabetes (CON; 14f/4m, 44·5 ± 2·1 years, BMI: 24 ± 1 kg m^?2; each P > 0·30), all with normal glucose tolerance as tested by three‐hour (75 g) oral glucose tolerance tests (OGTT). Two‐hour hyperinsulinaemic (40 mU min^?1·m^?2)isoglycaemic clamp tests were performed with simultaneous measurement of endogenous glucose (D‐[6,6‐²H₂]glucose) production (EGP). IMT [internal (ICA), common CA, and bulb] were measured sonographically. BCF was assessed by Adaptation Index (AI). Results Before and during OGTT, both groups were similar in plasma glucose, insulin, C‐peptide and free fatty acids (FFA), whereas OFF showed ~30% lower (P < 0·03) fasting plasma triglycerides before OGTT. During hyperinsulinaemic clamps, insulin sensitivity was ~38% lower (P < 0·03) in OFF who showed higher plasma FFA (44 ± 9 µmol L^?1) than CON (26 ± 3 µmol L^?1, P < 0·05) after 90 min. EGP was similar in both groups. OFF had 38% (P < 0·007) reduced AI. ICA‐IMT was ~18% higher in OFF (P < 0·002), but did not correlate with insulin sensitivity. Conclusion The data obtained show middle‐aged T2DM‐OFF with normal glucose tolerance displaying reduced total insulin sensitivity and impaired beta cell function, which relates to impaired insulin‐dependent suppression of plasma FFA and increased ICA‐IMT.