Intra- and Inter-rater Reliability of Peripheral Arterial Blood Flow Velocity by Means of Doppler Ultrasound

Turbo spin-echo-based enhanced acceleration-selective arterial spin labeling without electrocardiography or peripheral pulse unit triggering and contrast enhancement for lower extremity MRA

PURPOSE

Lower extremity magnetic resonance angiography (MRA) without electrocardiography (ECG) or peripheral pulse unit (PPU) triggering and contrast enhancement is beneficial for diagnosing peripheral arterial disease (PAD) while avoiding synchronization failure and nephrogenic systemic fibrosis. This study aimed to compare the diagnostic performance of turbo spin-echo-based enhanced acceleration-selective arterial spin labeling (eAccASL) (TSE-Acc) of the lower extremities with that of turbo field-echo-based eAccASL (TFE-Acc) and triggered angiography non-contrast enhanced (TRANCE).

METHODS

Nine healthy volunteers and a patient with PAD were examined on a 3.0 Tesla magnetic resonance imaging (MRI) system. The artery-to-muscle signal intensity ratio (SIR) and contrast-to-noise ratio (CNR) were calculated. The arterial visibility (1: poor, 4: excellent) and artifact contamination (1: severe, 4: no) were independently assessed by two radiologists. Phase-contrast MRI and digital subtraction angiography were referenced in a patient with PAD. Friedman's test and a post-hoc test according to the Bonferroni-adjusted Wilcoxon signed-rank test were used for the SIR, CNR, and visual assessment. p < 0.05 was considered statistically significant.

RESULTS

No significant differences in nearly all the SIRs were observed among the three MRA methods. Higher CNRs were observed with TSE-Acc than those with TFE-Acc (anterior tibial artery, p = 0.014; peroneal artery, p = 0.029; and posterior tibial artery, p = 0.014) in distal arterial segments; however, no significant differences were observed upon comparison with TRANCE (all p > 0.05). The arterial visibility scores exhibited similar trends as the CNRs. The artifact contamination scores with TSE-Acc were significantly lower (but within an acceptable level) compared to those with TFE-Acc. In the patient with PAD, the sluggish peripheral arteries were better visualized using TSE-Acc than those using TFE-Acc, and the collateral and stenosis arteries were better visualized using TSE-Acc than those using TRANCE.

CONCLUSION

Peripheral arterial visualization was better with TSE-Acc than that with TFE-Acc in lower extremity MRA without ECG or PPU triggering and contrast enhancement, which was comparable with TRANCE as the reference standard. Furthermore, TSE-Acc may propose satisfactory diagnostic performance for diagnosing PAD in patients with arrhythmia and chronic kidney disease.

Reliability of Ultrasound Imaging in Examining Integrity and Inflammation in the Dorsalis Pedis Artery

OBJECTIVE

Assessment of small vessel inflammatory diseases such as rheumatoid vasculitis is challenging. Small arteries such as the dorsalis pedis artery (DPA) are difficult to assess for changes in the arterial wall with medical imaging. Ultrasound imaging is a viable tool for examining the integrity and inflammatory changes in the arterial wall; however, no empirical data on its reliability have been described.

METHODS

We measured the intra- and inter-rater reliability of ultrasound measurements across five parameters evaluating arterial integrity of the proximal DPA in participants with and without small vessel disease. We recruited 10 participants with rheumatoid arthritis and 10 healthy controls. Two sonographers using ultrasound independently measured DPA lumen diameter, artery diameter, lumen-to-arterial diameter ratio, arterial Doppler velocity and inflammatory changes in the proximal wall of the DPA. The intraclass correlation coefficient (ICC) was used to evaluate 95% confidence intervals within and between raters. Bland-Altman analyses were used to assess limits of agreement and were compared with minimal clinically important differences (MCID).

RESULTS

Four of five selected parameters were found to have excellent intra- and inter-rater reliability within and between raters (ICC = 0.903-0.996). Acceptable reliability was found for measurement of arterial blood flow velocity within raters (ICC = 0.815-0.909), but not between raters (ICC = 0.634). Standard mean errors in all parameters were within minimal clinically important differences.

CONCLUSION

Ultrasound imaging has been found to be a reliable method of assessment of arterial integrity and inflammation of the proximal DPA in people with small vessel disease. Evaluation of arterial blood flow velocity requires cautious interpretation.

Endoleak Detection after Endovascular Aortic Repair via Coded-Excitation Ultrasound-A Feasibility Study

Endoleaks are the most common complication after endovascular aortic repair (EVAR). Their correct identification is one of the main objectives of surveillance protocols after EVAR. So far, computed tomography angiography (CTA), contrast-enhanced (CEUS) and Duplex ultrasound (DUS), as well as magnetic resonance angiography, have been investigated for their ability to detect endoleaks. In general, all technologies have distinct benefits and disadvantages, with CTA and CEUS emerging as the reference standard for surveillance after EVAR. However, they are both contrast-enhancer-dependent, and CTA additionally exposes patients to ionizing radiation. In the present study, we investigated B-Flow, a type of coded-excitation ultrasound that was specifically designed to optimize the visualization of blood flow, for its ability to detect endoleaks, and compared its performance to CEUS, CTA, and DUS. In total, 34 patients were included in the analysis that accumulated in 43 distinct B-Flow investigations. They underwent a total of 132 imaging investigations. Agreement between B-Flow and other imaging modalities was high (>80.0%), while inter-method reliability can be interpreted as good. However, with B-Flow, six and one endoleaks would have been missed compared to CEUS and CTA, respectively. Regarding endoleak classification, all metrics were lower but retained an adequate level of comparison. In a subset of patients requiring intervention, B-Flow had 100% accuracy regarding both endoleak detection and classification. Ultrasonography enables endoleak detection and classification without the need for pharmaceutical contrast enhancement or radiation. Ultrasound coded-excitation imaging in the application of B-Flow could further simplify surveillance after EVAR by offering adequate accuracy without requiring intravenous contrast enhancement. Our findings may promote subsequent investigations of coded-excitation imaging for endoleak detection and classification in the surveillance after EVAR.

Intra- and inter-examiner reliability of digital images of skin donor areas in burns

OBJECTIVE

The main objective of this study was to evaluate intra- and inter-rater reliability in the analysis of digital images of donor areas for skin in burn patients using the CaPAS plugin in the ImageJ®.

METHODS

Donor sites were reviewed by two independent reviewers in duplicate. The capture of images was standardized on the same device and distance (with a millimeter ruler), without a flash. The evaluators were trained to capture the images and use the plugin.

RESULTS

We selected 70 images from donor areas, from men and women between 18 and 60 years old. In the analysis of intra-examiner reliability, eight of the nine variables exhibited excellent reliability (0.985-0.998) and one (entropy) exhibited good reliability (0.525). The same was true for the inter-examiner analysis: excellent reliability for eight variables (0.824-0.993) and good reliability for entropy (0.501).

CONCLUSIONS

The CaPAS plugin has proven to be a reliable tool for use in research in skin donor areas in burns, as demonstrated by its excellent intra- and inter-examiner reliability values. This is a pioneering study in the quantitative assessment of skin donor areas in burn patients using the CaPAS plugin.

Correlation between the range of motion of the tibiotarsal joint and blood circulation in the lower limbs in diabetic individuals

OBJECTIVE

The aim of this study was to evaluate the relationship between the range of motion and lower-limb hemodynamic indices in the tibiotarsal joint of individuals with diabetic neuropathy.

METHODS

Twenty volunteers of both sexes, with a mean age of 61.45±7.05 years, were diagnosed with type 2 diabetes mellitus and diabetic peripheral neuropathy. Arterial blood flow was assessed using Doppler ultrasound, and the variables such as average velocity, pulsatility index, and resistivity index were also evaluated. A range of dorsiflexion and plantar flexion joint movements were assessed using digital goniometry before and after exercise. Data distribution was assessed using the Shapiro-Wilk test, followed by Pearson's correlation for normal data and Spearman's correlation for non-normal data, in order to verify the association between variables.

RESULTS

A moderate correlation was found between dorsiflexion and pulse rate on two occasions before (rs=0.497) and after initial evaluation (rs=0.511). A low correlation was found between plantar flexion and mean velocity (rs=-0.357), pulsatility index (rs=0.439), and resistivity index (rs=0.328); dorsiflexion and mean velocity (rs=0.374), pulse rate (rs=0.332), and resistance index (rs=0.327) before evaluation, and peak (rs=0.346) was observed after the evaluation of blood circulation.

CONCLUSION

There is a correlation between the range of motion of the tibiotarsal joint and the blood circulation of diabetics, ranging from moderate to poor for the different variables evaluated.

A comparison of variability between absolute and relative blood flow restriction pressures

Recommendations are that blood flow restriction (BFR) be applied relative to arterial occlusion pressure (AOP) to provide a similar stimulus.

PURPOSE

Compare variability of the change in blood flow, shear rate, and discomfort between recommended relative pressures and an absolute pressure.

METHODS

During one visit, brachial arterial blood flow was measured in 91 participants using pulse-wave Doppler ultrasonography. After 5-min seated rest, AOP was measured. Following another 5-min rest, blood flow and discomfort were assessed twice before cuff inflation as controls (C1 and C2), then again with a cuff inflated to each BFR pressure (all measures separated by 1-min). Change scores from C1 to all subsequent measures were calculated (i.e., C2-C1; 40%AOP-C1; 80%AOP-C1; 100mmHg-C1). Variability of the changes were compared via pairwise modified Pitman-Morgan tests (α=.008).

RESULTS

Variance (95%CI) of the change for blood flow (mL/min), shear rate (1/sec), and discomfort (AU) had similar trends. C2-C1 differed from all conditions (all p<.001), 40%AOP-C1 differed from 80%AOP-C1 and 100mmHg-C1 (all p<.001), which did not differ (both p≥.117). Blood flow: C2-C1=469.79 (357.90, 644.07), 40%AOP-C1=1263.18 (962.34, 1731.80), 80%AOP-C1=1752.90 (1335.42, 2403.18), 100mmHg-C1=1603.18 (1221.36, 2197.92); Shear rate: C2-C1=6248.24 (4760.10, 8566.15), 40%AOP-C1=14625.30 (11142.06, 20050.95), 80%AOP-C1=22064.02 (16809.13, 30249.27), 100mmHg-C1=20778.76 (15829.98, 28487.21); Discomfort: C2-C1=0.07 (0.05, 0.08), 40%AOP-C1=2.03 (1.55, 2.78), 80%AOP-C1=4.26 (3.25, 5.84), 100mmHg-C1=4.50 (3.43, 6.17).

CONCLUSION

Contrary to previous suggestions, applying relative pressures does not necessarily guarantee a similar stimulus. It seems that higher pressures produce more variable changes even if the external pressure applied is made relative to each individual. This article is protected by copyright. All rights reserved.

Intra-rater reliability of leg blood flow during dynamic exercise using Doppler ultrasound

Developing an exercise model that resembles a traditional form of aerobic exercise and facilitates a complete simultaneous assessment of multiple parameters within the oxygen cascade is critically for understanding exercise intolerances in diseased populations. Measurement of muscle blood flow is a crucial component of such a model and previous studies have used invasive procedures to determine blood flow kinetics; however, this may not be appropriate in certain populations. Furthermore, current models utilizing Doppler ultrasound use isolated limb exercise and while these studies have provided useful data, the exercise model does not mimic the whole-body physiological response to continuous dynamic exercise. Therefore, we aimed to measure common femoral artery blood flow using Doppler ultrasound during continuous dynamic stepping exercise performed at three independent workloads to assess the within day and between-day reliability for such an exercise modality. We report a within-session coefficient of variation of 5.8% from three combined workloads and a between-day coefficient of variation of 12.7%. These values demonstrate acceptable measurement accuracy and support our intention of utilizing this noninvasive exercise model for an integrative assessment of the whole-body physiological response to exercise in a range of populations.

Optimized enhanced acceleration selective arterial spin labeling (eAccASL) for non-gated and non-enhanced MR angiography of the hands

PURPOSE

Enhanced acceleration selective arterial spin labeling (eAccASL) was introduced as non-enhanced and non-gated magnetic resonance angiography (MRA). This technique has not been applied to hand MRA. The objective of this study was to optimize the eAccASL for MRA of the hands and to investigate the factors for MRA visibility of the hands.

METHODS

Twenty healthy volunteers were examined on a 1.5 T MR system. To evaluate arterial visualization, we compared four different acceleration-encoding (AENC) values (i.e., 0.12, 0.29, 0.58, and 0.87 m/s²). Image quality score regarding the MRA depiction of the proximal artery (range, 0-10), the distal artery (0-5), and venous contamination (0-5) was evaluated by three radiologists. We measured the peak to peak arterial blood flow velocity (Vpp) measured by phase contrast cine MRI and hand temperature as the factors for arterial visualization. Qualitative scores were compared with Friedman's tests. Spearman's correlation of qualitative scores with Vpp and hand temperature was performed to analyze influencing factors.

RESULTS

For the distal arterial depiction, scores at AENC 0.12 (median, 9.0) and AENC 0.29 (8.0) were significantly better (both P < 0.0001) than those at AENC 0.87 (5.5). For the proximal arterial depiction, scores at AENC 0.12 (2.25) and AENC 0.29 (2.0) were significantly better (P < 0.001 and P < 0.01, respectively) than those at AENC 0.87 (1.5). Conversely, venous contamination scores at AENC 0.12 (3.0) and AENC 0.29 (3.0) were significantly worse (both P < 0.0001) than those at AENC 0.87 (4.0). There were significantly negative correlations between venous contamination and Vpp at AENC 0.12 (ρ = -0.56, P = 0.01), and 0.29 (ρ = -0.68, P = 0.001), whereas hand temperatures were not significantly correlated with scores (all P > 0.05).

CONCLUSION

eAccASL MRA of the hands was optimized by using low AENC values (0.12-0.29 m/s²). Venous contamination may increase with elevation of arterial blood flow.

Reliability and Accuracy of 2-Minute Step Test in Active and Sedentary Lean Adults

OBJECTIVE

The purpose of this study was to evaluate the intrarater and interrater reliability of the 2-minute step test (2MST) in active and sedentary lean adults and to identify the test cutoff point to differentiate active from sedentary individuals.

METHODS

This observational study involved 4 mixed-sex groups (each with 50 lean participants): group 1, sedentary and aged 18 to 24 years; group 2, active and aged 18 to 24 years; group 3, sedentary and aged 25 to 44 years; and group 4, active and aged 25 to 44 years. The 2MST was administered independently by 2 examiners (with 3 months' training) at 2 different times, with a 7-day interval. Habitual physical activity was evaluated by means of the Baecke Questionnaire (BQ). In statistical analysis, the Pearson correlation coefficient was used to verify the correlation between the 2MST and BQ; intraclass correlation coefficients (ICC_2,3) were used to determine the intrarater and interrater reliability of the 2MST; and the receiver operating characteristic curve was used to identify the accuracy of the 2MST.

RESULTS

Excellent intrarater and interrater reliability were found for all 4 groups (intraclass correlation coefficients ≥ 0.83). Correlating the 2MST score with the BQ score, a significant, positive, weak correlation was observed (r = 0.344, P < .001). For differentiating active from sedentary individuals, the 2MST showed low accuracy (area under the curve = 0.671), with 61% sensitivity and 67% specificity.

CONCLUSION

This study showed that the 2MST is a reliable test with a low amount of inherent error. There was a significant correlation between the 2MST and usual physical activity measured, and slight accuracy in differentiating active from sedentary individuals.

Volume Flow and Peak Systolic Velocity of the Arteriovenous Circuit in Patients after Percutaneous Deep Venous Arterialization

Percutaneous deep venous arterialization (pDVA) is a developing technique for limb salvage in patients with chronic limb-threatening ischemia by creating an arteriovenous (AV) circuit. After pDVA, patency of the AV circuit is evaluated using duplex ultrasound (DUS) imaging. Peak systolic velocity (PSV) and volume flow (VF) values for maintaining a patent AV circuit are undefined; therefore, guidance about when a reintervention should be performed is lacking. The objective of this study was to interpret post-pDVA PSV and VF values in relation to AV circuit preservation. This was performed by analyzing DUS results of 22 post-pDVA patients. A total of 670 PSV and 623 VF measurements were collected. A PSV value of ≤55 cm/s and a VF value of ≤195 mL/min were found predictive for failure. The reliability of PSV and VF measurements in patent AV-circuits was good (intraclass correlation coefficient; PSV, 0.85; VF, 0.88). In conclusion, this study is the first to analyze DUS measurements in post-pDVA patients and showed that DUS can be used to anticipate for failure. The thresholds found can be used to help interpret DUS measurements in post-pDVA patients. More research in a larger patient population is needed to prospectively validate these thresholds.

Peripheral arterial disease screening and diagnostic practice: A scoping review

Early reliable, valid screening, diagnosis, and treatment improve peripheral arterial disease outcomes, yet screening and diagnostic practices vary across settings and specialties. A scoping literature review described reliability and validity of peripheral ischaemia diagnosis or screening tools. Clinical studies in the PUBMED database January 1, 1970, to August 13, 2018, were reviewed summarising ranges of reliability and validity of peripheral ischaemia diagnostic and screening tools for patients with non-neuropathic lower leg ischaemia. Peripheral ischaemia screening and diagnostic practices varied in parameters measured such as timing, frequency, setting, ordering clinicians, degree of invasiveness, costs, definitions, and cut-off points informing clinical and referral decisions. Traditional ankle/brachial systolic blood pressure index <0.9 was a reliable, valid lower leg ischaemia screening test to trigger specialist referral for detailed diagnosis. For patients with advanced peripheral ischaemia or calcified arteries, toe-brachial index, claudication, or invasive angiographic imaging techniques that can have complications were reliable, valid screening, and diagnostic tools to inform management decisions. Ankle/brachial index testing is sufficiently reliable and valid for use during routine examinations to improve timing and consistency of peripheral ischaemia screening, triggering prompt specialist referral for more reliable, accurate Doppler, or other diagnosis to inform treatment decisions.

Effects on the Profile of Circulating miRNAs after Single Bouts of Resistance Training with and without Blood Flow Restriction-A Three-Arm, Randomized Crossover Trial

BACKGROUND

The effects of blood flow restriction (training) may serve as a model of peripheral artery disease. In both conditions, circulating micro RNAs (miRNAs) are suggested to play a crucial role during exercise-induced arteriogenesis. We aimed to determine whether the profile of circulating miRNAs is altered after acute resistance training during blood flow restriction (BFR) as compared with unrestricted low- and high-volume training, and we hypothesized that miRNA that are relevant for arteriogenesis are affected after resistance training.

METHODS

Eighteen healthy volunteers (aged 25 ± 2 years) were enrolled in this three-arm, randomized-balanced crossover study. The arms were single bouts of leg flexion/extension resistance training at (1) 70% of the individual single-repetition maximum (1RM), (2) at 30% of the 1RM, and (3) at 30% of the 1RM with BFR (artificially applied by a cuff at 300 mm Hg). Before the first exercise intervention, the individual 1RM (N) and the blood flow velocity (m/s) used to validate the BFR application were determined. During each training intervention, load-associated outcomes (fatigue, heart rate, and exhaustion) were monitored. Acute effects (circulating miRNAs, lactate) were determined using pre-and post-intervention measurements.

RESULTS

All training interventions increased lactate concentration and heart rate (p < 0.001). The high-intensity intervention (HI) resulted in a higher lactate concentration than both lower-intensity training protocols with BFR (LI-BFR) and without (LI) (LI, p = 0.003; 30% LI-BFR, p = 0.008). The level of miR-143-3p was down-regulated by LI-BFR, and miR-139-5p, miR-143-3p, miR-195-5p, miR-197-3p, miR-30a-5p, and miR-10b-5p were up-regulated after HI. The lactate concentration and miR-143-3p expression showed a significant positive linear correlation (p = 0.009, r = 0.52). A partial correlation (intervention partialized) showed a systematic impact of the type of training (LI-BFR vs. HI) on the association (r = 0.35 remaining after partialization of training type).

CONCLUSIONS

The strong effects of LI-BFR and HI on lactate- and arteriogenesis-associated miRNA-143-3p in young and healthy athletes are consistent with an important role of this particular miRNA in metabolic processes during (here) artificial blood flow restriction. BFR may be able to mimic the occlusion of a larger artery which leads to increased collateral flow, and it may therefore serve as an external stimulus of arteriogenesis.

A cooling cuff compared to a moist ice pack on radial artery blood flow and lumen diameter in healthy participants

BACKGROUND

Cryotherapy is a favourable treatment for post-traumatic injuries in the acute stage because of its effect on inflammation and pain. A novel cooling cuff, which can be easily used and can be wrapped around the injured area that does not require freezing, has been developed. Its efficacy compared to traditional ice therapy has not been established.

AIM

To establish the effect of a cooling cuff on radial artery blood flow and lumen diameter compared to moist ice.

SETTING

Chiropractic clinic and radiographic laboratory.

METHOD

A controlled laboratory pre-test post-test investigation assessed asymptomatic participants who were randomly allocated into a moist ice pack (n = 22) or the cooling cuff (n = 21) group. The intervention was placed on the participants forearm over the radial artery for 15 min. Data was collected by a qualified diagnostic radiographer using Doppler ultrasound. Data was analysed, using repeated measures analysis of variance to assess changes in blood flow and lumen diameter pre- and post-intervention. A p-value of less than 0.05 was considered significant.

RESULTS

Both groups showed a significant decrease in radial artery blood flow (p < 0.001) after 15 min with no significant changes being observed in diameter size. No significant differences were observed between the groups for radial artery blood flow or diameter.

CONCLUSION

The cooling cuff resulted in a similar effect on radial artery blood flow and lumen diameter as moist ice, indicating that patients and practitioners may utilise the cooling cuff in the acute phases of an injury to alter blood flow.

Reliability of skin impedance in subjects with chronic neck pain

BACKGROUND

Skin impedance is a biological signal that has been employed in the measurement of pain. However, there are few scientific data on skin impedance, with a great variety of assessment methods and controversial results.

OBJECTIVE

To examine the intra- and inter-rater reliability of skin impedance measurement in individuals with chronic neck pain.

METHODS

This is a blind cross-sectional study. Thirty individuals of both genders, aged between 18 and 45 years and with chronic neck pain were included in the study. Two examiners assessed skin impedance of the upper and lower limbs and torso at two intervals separated by one week. For statistical analysis, we used the intraclass correlation coefficient (ICC2,3) to determine the intra- and inter-rater reliability of skin impedance, with its respective confidence interval of 95%, standard error of measurement (SEM) and minimum detectable change (MDC).

RESULTS

The intra-rater reliability was considered substantial to excellent, with ICC values ranging between 0.843 and 0.978, SEM between 0.58 and 15.26 Ω, and MDC between 1.61 and 42.31 Ω. The inter-rater reliability was moderate to excellent, with ICC values ranging between 0.761 and 0.997, SEM ranging between 0.22 and 16.72 Ω, and MDC ranging between 0.63 and 46.35 Ω.

CONCLUSION

The measurement of skin impedance of the upper and lower limbs and torso in individuals with chronic neck pain has acceptable reliability values when considered at different times and by different examiners.