Measurement Of Stenosis Research Articles

Efficacy of fractional flow reserve measurement in the assessment of stenotic lesions of coronary artery

Context: The decision to perform an intervention on a narrowed coronary artery depends on the ischemia caused by the stenosis. The indication for intervention usually applies to cases with ≥70% stenosis of vascular diameter because of the risk of myocardial ischemia. Aims: To define the efficacy of fractional flow reserve (FFR) measurement in the evaluation of coronary artery stenosis. Methods: This prospective study was conducted on patients with intermediate coronary artery stenosis who underwent quantitative coronary angiography after coronary computed tomography angiography. Results: The study population consisted of 46 men and 26 women with a mean age of 66.0 ± 12.9 years. FFR was significantly correlated with the grade of angina pectoris (r = – 0.387; p<0.01) and showed a negative correlation with percentage diameter stenosis (r = – 0.241, p<0.05) and a positive correlation with the minimal lumen diameter (MLD; r = 0.377, p<0.05). The cut-off value to predict positive FFR was >55.62% diameter stenosis and MLD ≤ 1.08 mm. FFR ≤ 0.80 indicating intervention and FFR > 0.80 indicating medical therapy were observed in 56.9% and 43.1% of the cases, respectively. No major cardiac complications occurred during 12 months of follow-up in both groups. Conclusions: FFR measurements for intermediate stenosis of the coronary artery should be used to evaluate the possibility of myocardial ischaemia. If FFR is not available, a cut-off point of >55.62% diameter stenosis or MLD ≤ 1.08 mm can be used to predict the FFR results.

Mathematical Analysis of an Atherosclerotic Artery in Presence of Externally Applied Magnetic Field

In general Atherosclerosis is the narrowing of the arteries caused by formation of plaque (fat and calcium) in inner arterial wall. Hardening in inner wall of the arteries restricts the speed of flow in the arteries, which prevents the organs and tissues to get sufficient oxygenated blood for smooth functioning. The characteristics of blood and its flow can deliberate the fundamental understanding with respect to different rheological and haemodynamic properties of blood, which may help in detection and medication of several cardio-vascular, cerebro-vascular and arterial diseases. Many cardio-vascular diseases are caused due to abnormal flow of blood caused by stenosis (tapered segment in local lumen of the inner arterial wall). The arterial turbulence and flow variations are mainly caused by means of unpleasant arterial flow of blood and viscous head losses due to stenosis. The platelets of blood are generally activated by means of very high shear-stresses near stenosis-throat. The induced thrombosis may cause reduced flow velocity of blood flow to the brain and heart. The collective applications of analytical measures and numerical techniques may analyze the problem for more quantifiable investigation. It has been notified to different analytical study that the resistance of flow causes the increase of inner wall skin-friction with simultaneous increase of height of stenosis. Here the character of flow in artery is considered as axi-symmetric in nature. The measure of asymmetrical stenosis found from a mild stenosed artery in threedimensional structure, so that from physiological approach analysis would be more authentic under consideration with the different parameters of flow. According to the rheological parameters the flow model is considered to be Herschel-Bulkley fluid Model. The outcomes connected to Newtonian model of flow are represented as a distinct event of investigations by assuming the suitable values of fluid-index considered as “n”. Blood is characterized as a fluid having electrical conductance, the externally applied magneto hydrodynamic effects are also applied to reduce the flow acceleration of blood in arteries. The analysis is much efficient to explore the collective measures of data information related to phenomena of physiological problem in Atherosclerotic artery.

Abstract 9856: Associations of a Polygenic Risk Score (PGS) with High Risk Coronary Artery Disease (CAD) in PROMISE (Prospective Multicenter Imaging Study for Evaluation of Chest Pain)

Introduction: PGSs summarize the polygenic risk for CAD and may have clinical utility. We tested whether a previously validated PGS for CAD is associated with coronary CT angiography (CTA) findings predictive of future cardiovascular events in the PROMISE trial, which randomized individuals with stable outpatient chest pain to standard of care vs. CTA. Methods: This nested case-control study compared genotyped PROMISE participants with no CAD (0% stenosis), obstructive CAD (oCAD, ≥50% stenosis) or high-risk CAD defined as either oCAD ≥70% stenosis, CAC >400, Leaman Score > 5 (measure of stenosis and plaque burden), or any high-risk plaque feature (positive remodeling, low attenuation, napkin ring sign) on CTA. The Illumina Global Screening Array with imputation from the 1000 Genomes reference panel was used with LDpred to calculate ancestry-adjusted PGS. We calculated adjusted odds ratios (aORs) of oCAD and high-risk CAD for PGS quintiles 2-5 with quintile 1 as the referent using logistic regression and age, sex, and European Society of Cardiology pre-test probability (PTP) for obstructive CAD as covariates. Results: Among the 518 participants, 414=no CAD, 86=oCAD, and 103=high risk CAD (overlap of oCAD and high-risk CAD=85), the median age (±S.D.) was 58 (±7) years, 58% were female, and 13% were of non-white race or Hispanic ethnicity. Baseline characteristics, family history of premature CAD, PTP risk score and medications were similar across PGRS quintiles (all P>0.2). After multivariate adjustment, PGRS quintile 5 was associated with significantly increased odds of oCAD ≥50% (aOR 6.09) and high-risk CAD (aOR 6.13) as compared with quintile 1. Conclusions: In a population of stable symptomatic outpatients, higher PGS was associated with oCAD and high-risk CAD on CTA, even after adjustment for age, sex and pretest probability of CAD. The PGS may be useful for risk stratification of outpatients with suspected CAD.

Abstract 13330: Deep Learning Algorithm Predicts Angiographic Diameter Stenosis in Stable Patients Using Only a Standard 12-lead Electrocardiogram

Introduction: Current standard electrocardiogram analysis algorithms cannot predict the presence and extent of coronary artery disease (CAD), especially in stable patients. Hypothesis: A novel artificial intelligence algorithm (ECGio) is able to predict the presence, location, and severity of coronary artery lesions in a minimally selected stable patient population as verified by coronary angiography. Methods: A cohort of 1659 stable outpatients were randomly divided into training (86%) and validation (14%) subsets, maintaining population characteristics. ECGio was trained and then validated using electrocardiograms paired with angiograms collected from electronic medical records. Coronary artery lesions were evaluated by a continuous measure of stenosis ranging from 0% - 100%. The prediction was then compared to the angiogram result (worst diameter stenosis in each vessel) with the error calculated per patient and per vessel. Results: In the primary analysis of the validation cohort, 22 had no angiographic CAD and were grouped with 56 patients with mild CAD (DS ≤30%), 31 had moderate CAD (DS 30-70%), and 113 had severe CAD (DS ≥70%). On a vessel level ECGio was able to predict stenosis severity with an overall average error of 16% as well as vessel specific errors of 18% in the LAD, 19% in the LCX, 18% in the RCA, and 8% in the Left Main. Absolute Error and Left Main error can be seen in the Figure. Conclusion: This validation study strongly suggests that it is possible to utilize an artificial intelligence algorithm to determine the presence and severity of CAD in stable patients using data from a standard 12- lead electrocardiogram.

A New Doppler-Derived Parameter to Quantify Internal Carotid Artery Stenosis: Maximal Systolic Acceleration

Doppler ultrasonography (DUS) is used as initial measurement to diagnose and classify carotid artery stenosis. Local distorting factors such as vascular calcification can influence the ability to obtain DUS measurements. The DUS derived maximal systolic acceleration (ACCmax) provides a different way to determine the degree of stenosis. While conventional DUS parameters are measured at the stenosis itself, ACCmax is measured distal to the internal carotid artery (ICA) stenosis. The value of ACCmax in ICA stenosis was investigated in this study. All carotid artery DUS studies of a tertiary academic center were reviewed from October 2007 until December 2017. Every ICA was included once. The ACCmax was compared to conventional DUS parameters: ICA peak systolic velocity (PSV), and PSV ratio (ICA PSV/ CCA PSV). ROC-curve analysis was used to evaluate accuracy of ACCmax, ICA PSV and PSV ratio as compared to CT-angiography (CTA) derived stenosis measurement as reference test. The study population consisted of 947 carotid arteries and was divided into 3 groups: <50% (710/947), 50-69% (109/947), and ≥70% (128/947). Between these groups ACCmax was significantly different. Strong correlations between ACCmax and ICA PSV (R2 0.88) and PSV ratio (R2 0.87) were found. In ROC subanalysis, the ACCmax had a sensitivity of 90% and a specificity of 89% to diagnose a ≥70% ICA stenosis, and a sensitivity of 82% and a specificity of 88% to diagnose a ≥50% ICA stenosis. For diagnosing a ≥50% ICA stenosis the area under the curve (AUC) of ACCmax (0.88) was significantly lower than the AUC of PSV ratio (0.94) and ICA PSV (0.94). To diagnose a ≥70% ICA stenosis there were no significant differences in AUC between ACCmax (0.89), PSV ratio (0.93) and ICA PSV (0.94). ACCmax is an interesting additional DUS measurement in determining the degree of ICA stenosis. ACCmax is measured distal to the stenosis and is not hampered by local distorting factors at the site of the stenosis. ACCmax can accurately diagnose an ICA stenosis, but was somewhat inferior compared to ICA PSV and PSV ratio to diagnose a ≥50% ICA stenosis.

Relationship Between Simulated Gadolinium-Based Contrast Agent Injection Profile and Achievable Resolution Metrics in Contrast-Enhanced Magnetic Resonance Angiography.

Contrast bolus variation during contrast-enhanced magnetic resonance angiography (CE-MRA) acquisition may lead to vessel blurring. To combine knowledge of how contrast signal intensity (SI) evolves for different injection strategies with anatomically familiar parametric computer models to measure and visually assess the effects of a wide range of variables on modeled CE-MRA, and in doing so develop contrast rate injection guidelines. Computer modeling. Digital three-dimensional phantom consisting of orthogonal "aorta," 7 mm diameter "renal arteries" (with 57% and 86% diameter stenoses), and 7 mm diameter "superior mesenteric artery" (with 57% diameter stenosis). One millimeter in-plane resolution arterial CE-MRA imaging at 3 T. "Background" (time invariant) and "vascular" (time varying) components of the phantom were each Fourier transformed into the spatial frequency domain, the latter modulated by the SI evolution of a contrast bolus of varying "plateau" lengths and "tail" heights. Data are presented as surface plots of stenosis measurement error and blurring vs. a reference-standard injection. Descriptive. Shorter plateau lengths and lower tail heights resulted in increased measured stenosis error and blurring vs. the reference standard. Under a 44-second acquisition, full width half maximum stenosis error of the 86% stenosis with 25% plateau length and 25% tail height is 24% as compared to that from the reference standard. As plateau length and tail height approach 100%, stenosis error and blurring approach a floor defined by the MR acquisition's limitations. We propose that to achieve minimal degradation with CE-MRA, one can create a contrast bolus with either 60% plateau and 50% tail height or 80% plateau with any tail. These considerations may well prove to be of practical importance, possibly via manipulating the tail by means of multiphasic contrast injections. 3 TECHNICAL EFFICACY: Stage 1.

Insights from intravascular pressure measurement of renal artery revascularization in patients with fibromuscular dysplasia: The DYSART study

ObjectiveThe indication of percutaneous renal transluminal angioplasty (PTRA) in fibromuscular dysplasia (FMD) is mainly based on renal artery stenosis (RAS) due to atherosclerosis criteria, which are not specific to FMD. Consequently, the selection of patients who could benefit from this treatment and its effectiveness remain uncertain. The aims of this study were to: (1) report the effects of PTRA guided by trans-stenotic pressure measurements on hypertension 7 months after treatment; (2) assess the impact of pressure measurement to guide treatment efficacy in comparison to visual angiographic parameters; and (3) evaluate the reproducibility and accuracy of the stenosis measurement using a 4F catheter in comparison to a pressure guidewire. MethodsThis prospective multi-centric study analyzed 24 patients with hypertension with RAS due to FMD that required PTRA. Clinical, duplex ultrasound, and angiographic indices were collected, and patients were followed up for 7 months (±1 month). Angiographic indices were measured twice both by a pressure guidewire and a 4F catheter. Assessment of procedural and clinical success of angioplasty was performed for all patients. ResultsTwenty-three patients (96%) had procedural success (considered as a post-PTRA translesional systolic gradient ≤10 mmHg or reduced by at least 80%) with a significant decrease in the systolic gradient after angioplasty (26.50 mmHg; [interquartile range, 16.75-38.75] vs 0.00 [interquartile range, 0.00-2.00]; P < .01). Three patients (12%) had complications, including two renal artery dissections and one partial renal infarction. Twenty-one patients (88%) were clinical responders to angioplasty at follow-up. Visual stenosis assessment showed a poor correlation with systolic gradient measurement before and after PTRA (R from −0.05 to 0.41; P = 0.06-0.82). High correlations were found between pressure measurements made by a 4F catheter and guidewire (R from 0.64 to 0.89; P ≤ .003). ConclusionsIn patients selected by clinical indicators and duplex ultrasound, reaching a translesional systolic gradient ≤10 mmHg or reduced by at least 80% after angioplasty, promotes a high success rate for PTRA in hypertension due to FMD RAS.

The Use of Pointwise Encoding Time Reduction With Radial Acquisition MRA to Assess Middle Cerebral Artery Stenosis Pre- and Post-stent Angioplasty: Comparison With 3D Time-of-Flight MRA and DSA.

Background and Purpose: 3D pointwise encoding time reduction magnetic resonance angiography (PETRA-MRA) is a promising non-contrast magnetic resonance angiography (MRA) technique for intracranial stenosis assessment but it has not been adequately validated against digital subtraction angiography (DSA) relative to 3D-time-of-flight (3D-TOF) MRA. The aim of this study was to compare PETRA-MRA and 3D-TOF-MRA using DSA as the reference standard for intracranial stenosis assessment before and after angioplasty and stenting in patients with middle cerebral artery (MCA) stenosis.Materials and Methods: Sixty-two patients with MCA stenosis (age 53 ± 12 years, 43 males) underwent MRA and DSA within a week for pre-intervention evaluation and 32 of them had intracranial angioplasty and stenting performed. The MRAs' image quality, flow visualization within the stents, and susceptibility artifact were graded on a 1–4 scale (1 = poor, 4 = excellent) independently by three radiologists. The degree of stenosis was measured by two radiologists independently on DSA and MRAs.Results: There was an excellent inter-observer agreement for stenosis assessment on PETRA-MRA, 3D-TOF-MRA, and DSA (ICCs > 0.90). For pre-intervention evaluation, PETRA-MRA had better image quality than 3D-TOF-MRA (3.87 ± 0.34 vs. 3.38 ± 0.65, P < 0.001), and PETRA-MRA had better agreement with DSA for stenosis measurements compared to 3D-TOF-MRA (r = 0.96 vs. r = 0.85). For post-intervention evaluation, PETRA-MRA had better image quality than 3D-TOF-MRA for in-stent flow visualization and susceptibility artifacts (3.34 ± 0.60 vs. 1.50 ± 0.76, P < 0.001; 3.31 ± 0.64 vs. 1.41 ± 0.61, P < 0.001, respectively), and better agreement with DSA for stenosis measurements than 3D-TOF-MRA (r = 0.90 vs. r = 0.26). 3D-TOF-MRA significantly overestimated the stenosis post-stenting compared to DSA (84.9 ± 19.7 vs. 39.3 ± 13.6%, p < 0.001) while PETRA-MRA didn't (40.6 ± 13.7 vs. 39.3 ± 13.6%, p = 0.18).Conclusions: PETRA-MRA is accurate and reproducible for quantifying MCA stenosis both pre- and post-stenting compared with DSA and performs better than 3D-TOF-MRA.

Carotid Plaque Imaging: Strategies beyond Stenosis.

Atherosclerosis at the carotid bifurcation in the neck is common and the result of turbulent hemodynamics in the bulb. Carotid bulb plaques cause disabling strokes. Carotid vessel wall imaging characterizes the atherosclerotic plaque, documents disease progression, and assesses lesion severity by plaque morphology in addition to the degree of stenosis. This in turn optimizes treatment selection for the individual patient. The aim of vessel wall imaging in patients of stroke is to distinguish stable plaques that may be conserved with best medical management from unstable or vulnerable plaques that require more aggressive medical treatment, carotid stenting, or carotid endarterectomy. Growing evidence suggests that depending on luminal stenosis measurements alone for management decisions will result in underestimating a number of plaques whose size may be small, but where the plaque morphology is unstable, there is a high likelihood of the patient developing a thromboembolic stroke in the near future. In today's context of aggressive management of even transient ischemic attacks and minor strokes, vessel wall imaging should be particularly performed in cryptogenic strokes without significant luminal narrowing on angiography to identify a subset of patients with nonstenotic but unstable atherosclerotic plaques that may be covert etiologies of stroke. If patients receiving the best medical management have recurrent strokes on the same side as a carotid plaque with “vulnerable” plaque features, they may deserve surgical or endovascular intervention even if they do not meet the conventional stenosis thresholds. Improved techniques for stroke imaging and consequent management have a remarkable effect in decreasing individual and public health burdens.

Transabdominal duplex ultrasound and intravascular ultrasound planimetry measures of common iliac vein stenosis are significantly correlated in a symptomatic population

ObjectiveThe objectives of the present study were to determine the validity of transabdominal duplex ultrasound (TAUS) against the reference standard of intravascular ultrasound (IVUS) examinations for the detection of iliac vein obstruction (IVO). MethodsWe analyzed the data from patients at a private vascular laboratory who had undergone IVUS investigation with an intention to treat because of symptoms of chronic venous insufficiency and a high suspicion of IVO. These patients had also previously undergone a TAUS examination at the same location. The TAUS and IVUS planimetry measures of the left common iliac vein (CIV) were correlated. These included the TAUS-measured minimum and maximum diameter and the percentage of stenosis with the IVUS-measured minimum and maximum diameter and area and the percentage of stenosis. ResultsThe TAUS and IVUS data from 47 patients (83% female; age, 49.3 ± 17.3 years; 64% obese) were included in the analyses. We found 89% agreement between the TAUS and IVUS findings regarding the identification of left CIV stenosis of ≥50%. The TAUS data had a positive predictive value of 95.5%. The TAUS measures of the minimum diameter and percentage of stenosis correlated significantly with the IVUS measures of the minimum diameter, minimum area, and cross-sectional area of the percentage of stenosis. The strongest correlations were between the TAUS-measured minimum diameter and IVUS-measured minimum area and percentage of the area of stenosis according to the literature-derived value. The TAUS-measured vein diameter of 8 mm equated to an IVUS cross-sectional area of 94.2 mm2 (53% stenosis), and an IVUS cross-sectional area of 50% of stenosis equated to a TAUS diameter of 8.56 mm. ConclusionsThe findings from the present study support the validity of TAUS evaluation as a workup diagnostic tool for the detection of IVO. Our findings also support the use of TAUS planimetry—in particular, the CIV diameter of ≤8 mm as a threshold value—to indicate clinically relevant stenosis and trigger an IVUS investigation with an intention to treat, because this correlated with a cross-sectional area stenosis of ≥50%, as determined by IVUS examination.

Defining Duplex Ultrasound Criteria for In-Stent Restenosis of the Superior Mesenteric Artery

This study sought to define duplex ultrasound (DUS) velocity criteria predicting ≥70% stenosis in superior mesenteric artery (SMA) stents by correlating in-stent peak systolic velocity (PSV) with computed tomographic angiography (CTA) measurements of percent stenosis. A retrospective review of 109 patients undergoing SMA stenting between 2003 and 2018 was conducted at a single institution. Thirty-seven surveillance duplex ultrasound studies were found to have a CTA performed within 30 days of study completion. Bare metal (n = 20) and covered stents (n = 17) were included. Velocities were paired to in-stent restenosis (ISR) measured by mean vessel diameter reduction on SMA centerline reconstructions from CTA. Receiver operating characteristic (ROC) curves was generated and logistic regression models for ≥70% ISR probability were used to define velocity criteria in the stented SMA. At a PSV of 300 cm/sec, the sensitivity is 100% and specificity 80% for a ≥70% in-stent SMA stenosis. At a PSV of 400 cm/sec, the sensitivity and positive predictive value (PPV) is 63% and the specificity and negative predictive value (NPV) is 90%. A PSV of 450 cm/sec was consistent with the highest specificity (100%) and PPV (100%) but lower sensitivity (50%) and NPV (87.9%). One patient with a PSV of 441 cm/sec on surveillance DUS died from complications of acute-on-chronic mesenteric ischemia. A PSV of 400 cm/sec on mesenteric DUS can predict ≥70% ISR with high sensitivity and should be considered as a diagnostic threshold for SMA in-stent restenosis.

Relationship between cognitive emotion regulation strategies and coronary heart disease: an empirical examination of heart rate variability and coronary stenosis

Objective Despite longstanding interest in emotion regulation and cardiovascular health, limited studies have investigated the relationship between cognitive emotion regulation (CER) strategies and coronary heart disease (CHD) using objective measures of heart rate variability (HRV) and coronary stenosis. This study aimed to objectively explore the associations between CER strategies and both HRV and coronary stenosis and provide empirical evidence for the relationship between emotion regulation and CHD. Methods Questionnaires on CER strategies were distributed to 251 CHD patients and 250 healthy persons. HRV and coronary stenosis were measured for CHD respondents using the 24-h dynamic electrocardiogram and coronary angiography, respectively. Results CHD patients with low HRV/severe stenosis used maladaptive emotion regulation more frequently and adaptive emotion regulation less frequently. Various maladaptive emotion regulation strategies (e.g. acceptance, rumination, putting into perspective) were positively associated with lower HRV and coronary stenosis severity, while adaptive emotion regulation strategies (e.g. positive refocusing, refocusing on planning) were negatively associated with lower HRV and coronary stenosis severity. Conclusions Patients with more serious diseases exhibited increased maladaptive emotion regulation, which was associated with lower HRV and severe coronary stenosis. Further, adaptive emotion regulation was associated with higher HRV and moderate coronary stenosis.

Deep Learning From Coronary Computed Tomography Angiography for Atherosclerotic Plaque and Stenosis Quantification and Cardiac Risk Prediction

Background: Atherosclerotic plaque quantification from coronary computed tomography angiography (CCTA) enables accurate assessment of coronary artery disease burden and prognosis. We sought to develop and externally validate a deep learning (DL) system for CCTA-derived measures of plaque volume and stenosis severity. Methods: This was an international multicenter study of patients undergoing CCTA at 11 sites. A novel DL convolutional neural network was trained to segment coronary plaque in 921 patients (5,045 lesions). The DL network was then applied to an independent test set, which included an external validation cohort of 175 patients (1,081 lesions) as well 50 patients (84 lesions) assessed by intravascular ultrasound (IVUS) within one month of CCTA. Thereafter, we evaluated the prognostic value of DL-based plaque measurements for fatal or nonfatal myocardial infarction (MI) in 1,611 patients from the prospective SCOT-HEART trial. Findings: In the overall test set, there was excellent agreement between DL and expert reader measurements of total plaque volume (intraclass correlation coefficient [ICC] 0·964) and percent diameter stenosis (ICC 0·879; both p<0.001). When compared with IVUS, there was excellent agreement for DL total plaque volume (ICC 0·949) and minimal luminal area (ICC 0·904). The average per-patient DL plaque analysis time was 5.7 seconds versus 25-30 minutes taken by experts. Over a median follow-up of 4·7 years, MI occurred in 41 patients (2·5%) from the SCOT-HEART trial. DL-based total plaque volume ≥238·5mm 3 was associated with an increased risk of MI (HR 5·36, 95% CI 1·70-16·86; p=0·004) after adjustment for the presence of DL-based obstructive stenosis (HR 2·49, 95% CI 1·07-5·50; p=0·009) and the cardiovascular risk score (HR 1·01, 95% CI 0·99-1·04; p=0·35). Interpretation: A novel externally validated DL system provides rapid measurements of plaque volume and stenosis severity from CCTA which agree closely with expert readers and IVUS and carry prognostic value for future MI. Funding: National Heart, Lung, and Blood Institute. Declaration of Interest: Outside of the current work, S.C., P.S., and D.D. received software royalties from Cedars-Sinai Medical Center. D.B, P.S., and D.D. hold a patent (US8885905B2 in USA and WO patent WO2011069120A1, Method and System for Plaque Characterization). All other authors have nothing to declare. Ethical Approval: This work was approved by the Institutional Review Boards and all patients provided written informed consent.

COMPARISON OF CAROTID STENOSIS GRADING BY CT ANGIOGRAPHY AND DOPPLER ULTRASONOGRAPHY: HOW THE STATISTICAL METHODS APPLIED INFLUENCE THE RESULTS.

SUMMARYIn this study, we compared the measurement of carotid stenosis by computed tomography angiography (CTA) based on the narrowest diameter versus cross sectional area (CSA) with the measurement by color Doppler ultrasonography (CDUS) as a reference standard, and analyzed how the application of different statistical methods affected the result. On 113 carotid arteries with ≥50% stenosis, we quantified the level of correlation among the three measurements, sensitivity, specificity, and differences in the estimated stenosis level. Correlation between both CTA measurements was good with Pearson’s ρ between 0.87 and 0.91 (p<0.001). Correlation between CDUS and CTA measurements was only modest with Pearson’s ρ between 0.2 (p=0.075) and 0.4 (p=0,007) for CDUS CTA (CSA), and between 0.23 (p=0.062) and 0.39 (p=0.008) for CDUS CTA (diameter). Differences in stenosis between CTA (CSA) and CDUS were centered around 0%, and between CTA (diameter) and CDUS around 20%. Sensitivity and specificity for CTA (CSA) method were 81% and 77%, and for CTA (diameter) 23% and 100%, respectively. A good correlation between CSA and diameter measurement just means that these are two related features of stenosis, it does not mean good agreement. CTA (CSA) method better detected surgical stenoses, whereas CTA (diameter) systematically underestimated stenosis level. The study of differences between the measurements indicated agreement better than the calculation of correlation coefficients.

Intravascular ultrasonography provides more sensitive detection of subclavian vein stenosis than venography in patients presenting with Paget-Schroetter syndrome

ObjectiveSpontaneous subclavian vein (SCV) thrombosis (Paget-Schroetter syndrome [PSS]) has been attributed to venous compression at the thoracic outlet and traditionally diagnosed using venography. Intravascular ultrasonography (IVUS) allows for a multidimensional view of vascular structures and might be more accurate in revealing venous compression. The goal of the present study was to compare venography and IVUS in patients presenting with PSS to assess the relative accuracy of each modality. MethodsPatients presenting for evaluation of PSS from 2013 to 2019 were evaluated for SCV compression using venography and IVUS. Venography and IVUS measurements of stenosis were performed of the index and contralateral limbs in both neutral and stress (arm overhead) positions. The IVUS data included the SCV diameters in the anteroposterior (AP) plane, craniocaudal (CC) plane, and cross-sectional area (CSA). Stenosis was reported as the percentage of reduction from a reference point (lateral margin of the first rib) for the venography and IVUS data. ResultsFor the 35 subjects, the average age was 35 years, 57% were women, 20% had presented with a documented pulmonary embolus, and 70% had initially been treated with thrombolysis. Venography demonstrated SCV occlusion in 3 patients (16%) with the index limb in the neutral position and in 18 patients (54%) with the limb in the stress position. The average stenosis in the index limbs was 41.5% (venography), and the average IVUS stenosis was 41.9% (CC), 61.8% (AP), and 74.5% (CSA; P < .05). A subset analysis revealed that in 10 of 35 patients (28%) in whom venography had identified no significant stenosis (average, 10%), IVUS had identified significant stenosis (33.5% CC, 54.3% AP, 68.7% CSA; P < .05). ConclusionsIVUS proved more sensitive than venography in detecting significant stenosis leading to SCV thrombosis. A reduction in the CSA was the most sensitive measure of stenosis. IVUS identified significant stenosis in patients in whom venography failed to do so. The greatest utility of IVUS is in the evaluation of patients with PSS in whom venography shows no evident compression.

Single rotation CTA of extracranial carotids integrated with cerebral CTP provides sufficient quality for decision making in patients with ischaemic stroke.

Large volume computed tomography scanners with 16 cm Z-axis single rotation coverage enable joggle-mode scanning of cerebral computed tomography perfusion and single rotation computed tomography angiography of cervical arteries. Our study aims to evaluate the feasibility of scanning cervical arteries, acquired with single rotation computed tomography angiography during computed tomography perfusion in ischaemic stroke patients. A total of 143 patients were scanned with a single contrast medium injection of 60 ml. Hounsfield units of the cervical arteries and veins were objectively measured and carotid bifurcations were subjectively reviewed. The incidence of artefacts and supra-aortic vessel coverage was recorded. Single rotation computed tomography angiography of the neck demonstrated supra-aortic vessels to their origins in 58 (40.6%) patients. Ninety-nine per cent (1140/1152) of arterial segments were adequately opacified (≥150 Hounsfield units). Arteries were adequately contrasted compared to veins in 81.3% (915/1126) of segments. However, the opacification was reversed in 14.0% (158/1126) of segments, indicating a delayed timing of acquisition; 95.5% (273/286) of carotid bifurcations were of good image quality. Measurement of internal carotid artery stenosis in single rotation computed tomography angiography according to the North American Symptomatic Carotid Endarterectomy Trial correlated well with digital subtraction angiography (R=0.87, P<0.05). Significant artefacts resulted from metal/dental implants (10.5%), contrast in central veins (7.7%) and the shoulder region (4.9%). Single rotation computed tomography angiography of the neck incorporated into cerebral computed tomography perfusion with single contrast medium administration revealed adequate image quality for further decision-making in our patient sample. The main drawbacks were inadequate coverage of supra-aortic arteries and possible delay in timing of the joggle.

Real World Accuracy of Carotid Artery Stenosis Measurements

Real World Accuracy of Carotid Artery Stenosis Measurements

Overcoming calcium blooming and improving the quantification accuracy of percent area luminal stenosis by material decomposition of multi-energy computed tomography datasets.

Purpose: Conventional stenosis quantification from single-energy computed tomography (SECT) images relies on segmentation of lumen boundaries, which suffers from partial volume averaging and calcium blooming effects. We present and evaluate a method for quantifying percent area stenosis using multienergy CT (MECT) images. Approach: We utilize material decomposition of MECT images to measure stenosis based on the ratio of iodine mass between vessel locations with and without a stenosis, thereby eliminating the requirement for segmentation of iodinated lumen. The method was first assessed using simulated MECT images created with different spatial resolutions. To experimentally assess this method, four phantoms with different stenosis severity (30% to 51%), vessel diameters (5.5 to 14mm), and calcification densities (700 to ) were fabricated. Conventional SECT images were acquired using a commercial CT system and were analyzed with commercial software. MECT images were acquired using a commercial dual-energy CT (DECT) system and also from a research photon-counting detector CT (PCD-CT) system. Three-material-decomposition was performed on MECT data, and iodine density maps were used to quantify stenosis. Clinical radiation doses were used for all data acquisitions. Results: Computer simulation verified that this method reduced partial volume and blooming effects, resulting in consistent stenosis measurements. Phantom experiments showed accurate and reproducible stenosis measurements from MECT images. For DECT and two-threshold PCD-CT images, the estimation errors were 4.0% to 7.0%, 2.0% to 9.0%, 10.0% to 18.0%, and to (ground truth: 51%, 51%, 51%, and 30%). For four-threshold PCD-CT images, the errors were 1.0% to 3.0%, 4.0% to 6.0%, to 9.0%, and 0.0% to 6.0%. Errors using SECT were much larger, ranging from 4.4% to 46%, and were especially worse in the presence of dense calcifications. Conclusions: The proposed approach was shown to be insensitive to acquisition parameters, demonstrating the potential to improve the accuracy and precision of stenosis measurements in clinical practice.

Instantaneous Wave-Free Ratio Measurement During Intracranial Submaximal Angioplasty: Case Series and 2-Dimensional Operative Video.

Instantaneous wave-free ratios (iFRs) are functional measures of arterial stenosis that have become essential to interventional cardiology procedures. Their use for intracranial submaximal angioplasty (angioplasty with an undersized balloon) has not been studied extensively. To describe the feasibility and technique of iFR measurement for stenosis assessment during intracranial angioplasty. We present a series of consecutive patients treated between January 1, 2017 and June 30, 2018 with submaximal intracranial angioplasty in whom pre- and postprocedure iFR measurements were obtained with a Verrata-Volcano pressure wire (Philips, Amsterdam, The Netherlands). We collected patient data on age, sex, comorbid conditions, presenting complaints, modified Rankin scale (mRS) score at admission, neurological findings, procedure duration, fluoroscopy time, intraprocedural complications, length of hospital stay, and mRS score at last clinical follow-up (favorable outcome, 0-2). Angiographic stenosis severity and iFR values were recorded before and after angioplasty. A total of 12 patients underwent iFR-guided angioplasty during the study period. The median patient age was 69.5 yr (range 48-81 yr). All patients had symptomatic intracranial arterial stenosis (3-basilar, 2-vertebral, 6-middle cerebral, 1-internal carotid). Preangioplasty stenosis ranged from 55% to 90%. The median postangioplasty reduction in stenosis was 17% (range 9%-30%). Preangioplasty values ranged from 0.30 to 0.40 (n=4). Postangioplasty values ranged from 0.6 to 0.9 (n=5). iFR values improved considerably in all patients. No procedure-related complications occurred. The median follow-up was 8.9 mo (range 3-25 mo). Follow-up outcomes were favorable in 10 patients. iFR measurement before and after intracranial angioplasty is feasible. It may be used to assess the adequacy of intracranial angioplasty.

Validation of computed tomography angiography using mean arterial pressure gradient as a reference in stented superior mesenteric artery

PurposeThe aim of this prospective study was to validate the diagnostic performance of computed tomography angiography (CTA) in endoprosthesis stenosis in the superior mesenteric artery (SMA) using mean arterial pressure (MAP) gradients during angiography as a reference method.MethodsTwenty-nine patients with mesenteric atherosclerotic disease underwent 45 paired measurements of endoprosthesis stenosis in the SMA with CTA and MAP gradients between March 2009 and July 2015. The grade of endoprosthesis stenosis in the SMA at CTA using the TeraRecon Aquarius workstation was correlated with MAP gradients.ResultsGrade of endoprosthesis stenosis in the SMA (r = 0.37, p = 0.013) correlated with MAP gradients. The intraclass correlations between the first and second CTA rater was 0.76 (95% CI 0.56–0.87) for estimation of grade of endoprosthesis stenosis in the SMA. The area under the receiver operating characteristics curve was 0.79 for diagnosis of significant endoprosthesis stenosis in the SMA at CTA for different threshold values using MAP gradient of ≥ 10 mmHg as reference. Sensitivity, specificity and positive predictive value for endoprosthesis stenosis in the SMA ≥ 50% at CTA were 52.4% (95% CI 31.0–73.7), 87.5% (95% CI 74.3–100.0) and 78.6 (95% CI 57.1–1.00), respectively.ConclusionGrading endoprosthesis stenosis in the SMA with CTA performed fair when using trans-stenotic MAP gradient as reference. Software development towards reduction of endoprosthesis artefacts may result in more accurate CTA assessment of the narrowest part.