Frequency domain laser ultrasound for inertial confinement fusion target wall thickness measurements

The clinical practice of measurement of wall thickness does not accurately predict the presence or absence of left ventricular hypertrophy: a prospective echocardiographic study

A 48-year-old man, with only a history of mild systemic hypertension, was initially evaluated after presenting with symptoms of exertional dyspnea occurring predominantly with inclines. At that time, an abnormal 12-lead ECG was obtained demonstrating left ventricular hypertrophy by conventional voltage criteria, prompting additional testing with a 2-dimensional echocardiogram that showed normal systolic function (ejection fraction=65%), with 14-mm ventricular septal thickness and 12 mm in the posterolateral wall, and mild systolic anterior motion (SAM) of the mitral valve (bend of anterior leaflet into outflow tract without septal contact). A stress nuclear stress test showed no myocardial ischemia at rest or at peak exercise with a normal blood pressure response and no arrhythmias or ST-T changes during exercise or in recovery. The patient was prescribed a β-blocker for treatment of systemic hypertension. During the next 2 years, the patient developed more limiting exertional symptoms with routine activities. β-Blocker dosage was increased, and a repeat echocardiogram demonstrated similar findings to the initial study, borderline left ventricular (LV) wall thickness despite well-controlled blood pressure. The abnormal ECG, and mild SAM at rest, raised consideration for a diagnosis of hypertrophic cardiomyopathy (HCM) and management for limiting heart failure symptoms. HCM is often suspected in a patient based on the presence of cardiovascular symptoms, detection of abnormal ECG, systolic ejection murmur on routine examination, or as part of pedigree screening.1,2 Abnormalities on ECG are present in >90% of patients with HCM, although no specific ECG pattern is pathognomonic.1 Clinical diagnosis of HCM can reliably be made in the majority of patients with 2-dimensional transthoracic echocardiography by imaging increased LV wall thickness (≥15 mm) with a nondilated cavity in the absence of any disease known to cause LV hypertrophy of that magnitude (ie, systemic hypertension or aortic stenosis).1–5 In …

Visualization of Clear Echocardiographic Images with Near Field Noise Reduction Technique: Experimental Study and Clinical Experience

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Endothelial dysfunction, believed to underlie the structural changes of atherosclerosis, is a systemic phenomenon. Despite this, the radial artery has been considered as devoid of atherosclerosis and is commonly used as a conduit in coronary artery bypass grafting (CABG). Recently, histological study has shown intimal hyperplasia and other structural changes consistent with early atherosclerosis in the radial artery. The objective of the present study was to determine if structural changes in the radial artery could be detected in vivo in patients with coronary atherosclerosis. Using high resolution echo-tracking, measurements of radial artery internal diameter, wall thickness and wall cross-sectional area were made in 25 patients awaiting CABG and in 20 controls. Digital and brachial blood pressures were also recorded. Mean arterial pressures did not differ between the patient and control groups. All measures of wall thickness were greater in the patient than the control group. Neither current arterial pressures nor past history of hypertension correlated with wall thickness. Using a model of analysis of covariance, coronary artery disease was the best single predictor of intima-media thickness, R(2)=48%, n=44, P<0.0005. We concluded that increased radial artery wall thickness can be demonstrated in vivo in patients with coronary atherosclerosis. This is a novel observation which seems to be independent of blood pressure, and is consistent both with the hypothesis of systemic endothelial dysfunction leading to systemic structural changes and also to the recent histological evidence for atherosclerotic changes in this vessel.

B-PO03-096 DIELECTRIC IMAGING ACCURATELY MEASURES REGIONAL CARDIAC CHAMBER WALL THICKNESS - AN IN VIVO STUDY

Two-stage artificial intelligence model for jointly measurement of atherosclerotic wall thickness and plaque burden in carotid ultrasound: A screening tool for cardiovascular/stroke risk assessment

Short-axis magnetic resonance images of the cardiac left ventricle, acquired in multiple slices and phases, may be used for the quantitative assessment of regional wall parameters. Conventional two-dimensional (2-D) methods for wall thickness measurement rely on information within one imaging plane, which may result in overestimation of the true thickness depending on the local direction of myocardial wall with respect to the imaging plane. To perform wall thickness measurements truly perpendicular to the myocardial wall, a three-dimensional (3-D) wall thickness calculation algorithm has been developed based on the 2-D improved centerline method. An evaluation was performed on left ventricular-shaped software phantoms, and on the magnetic resonance (MR) imaging data obtained from 20 healthy individuals. The 3-D method applied to software phantoms with an angulation within 20 degrees of the true short-axis orientation demonstrated only a 1.6% overestimation of wall thickness at the mid to low slices, and a 10.6% error at the apex (2-D measurements: 8.1% and 28.6%, respectively). Three-dimensionally calculated wall thickness in the healthy individuals was systematically and significantly smaller than corresponding 2-D wall thickness (by 11.2%, 8.7%, and 2.6% at the apical, low, and mid slices, respectively). Cardiac wall thickness measurements from short-axis MR studies can be obtained with a higher accuracy by the newly developed 3-D approach than with the conventional 2-D approach.

Geometric accuracy of intravascular ultrasound imaging.

Ultrasound Estimated Bladder Weight and Measurement of Bladder Wall Thickness—Useful Noninvasive Methods for Assessing the Lower Urinary Tract?

Carotid intima–media and adventitial thickening: Comparison of new and established ultrasound and magnetic resonance imaging techniques

The inclusion of Full Solution Rejuvenation (FSR®) in repairs of flight and aero-derivative gas turbine blades has shifted the primary cause for blade retirement from creep life consumption which is a function of service hours to primarily geometric limitations that are more governed by the cumulative number of repair cycles. For internally cooled components, one of the most significant causes for rejection is the remaining wall thickness of the airfoil. Operating blades with under-sized wall thickness can reduce the load-bearing capability and can increase the stresses that develop under transient thermal conditions found in operation. Typically, ultrasonic wall thickness measurement techniques are used during repair processing for determining remaining wall thickness on components but a number of limitations to obtaining accurate results with this process have been identified. Computed Tomography (CT) wall thickness inspection has addressed these limitations and become an important tool for extending the life of components beyond the typical OEM limits during repair. Entirely from the CT equipment user’s perspective, this paper explores a number of technical findings in the development of a highly accurate CT wall thickness inspection process for flight and aero-derivative gas turbine blades for utilization during repair after one or more service intervals. The importance of the accuracy of these wall thickness measurements is to ensure undersized blades are rejected and blades above the minimum wall thickness are accepted. Reducing uncertainty in the wall thickness measurements allows reconsideration of the acceptance limit and can result in more repairable blades returned for full service intervals. The target accuracy for measurements process was .002”. The findings described include aspects of equipment configuration, process parameters for the initial CT scanning, post-processing and interpretation, results validation specific to the component being measured and process limitations encountered.

Purpose To compare common carotid artery (CCA) wall thickness measured manually by using US and semiautomatically by using MRI, and to examine their associations with incident coronary heart disease and stroke. Materials and Methods This prospective study enrolled 698 participants without a history of clinical cardiovascular disease (CVD) from the Multi-Ethnic Study of Atherosclerosis (MESA) from July 2000 to December 2013 (mean age, 63 years; range, 45 to 84 years; same for men and women). All participants provided written informed consent. CCA wall thickness was measured with US as well as both noncontrast proton-density-weighted and intravenous gadolinium-enhanced MRI. Cox proportional hazards models were used to assess the associations between wall thickness measurements by using US and MRI with CVD outcomes. Results The adjusted hazard ratios for coronary heart disease, stroke, and CVD associated with per standard deviation increase in intima-media thickness were 1.10, 1.08, and 1.14, respectively. The corresponding associations for mean wall thickness measured with proton-density-weighted MRI were 1.32, 1.48, and 1.37, and for mean wall thickness measured with gadolinium-enhanced MRI were 1.27, 1.58, and 1.38. When included simultaneously in the same model, MRI wall thickness, but not intima-media thickness, remained associated with outcomes. Conclusion For individuals without known cardiovascular disease at baseline, wall thickness measurements by using MRI were more consistently associated with incident cardiovascular disease, particularly stroke, than were intima-media thickness by using US. © RSNA, 2018 Online supplemental material is available for this article.

Quantification of vessel wall thickness is important in longitudinal monitoring of atherosclerosis. Black-blood MRI has been useful in measuring vessel wall thickness. Studies using two-dimensional (2D) imaging protocols measured wall thickness by matching the arterial wall and lumen boundaries on an acquisition plane. If the acquisition plane is oblique to the artery, the wall thickness would be overestimated by a factor that is dependent on the obliqueness angle. This problem can be understood as a three-dimensional (3D) surface mismatch problem, and we evaluated the effect of this problem by comparing the thickness measurements obtained using a 2D contour matching method and a 3D surface matching method. In addition to the surface mismatch problem, two other parameters may affect the wall thickness estimation: reslicing angle and slice thickness. We measured the wall thickness using images resliced perpendicular to the centerline of the vessel and quantified the difference between the thickness measurements obtained from parallel and centerline-based resliced images. Images obtained from a 2D MRI protocol typically have a slice thickness of 2mm, while the 3D MRI technique applied in this study produced images with sub-millimeter isotropic voxel size. To investigate the effect of slice thickness, we simulated 2mm-thick images by averaging the 3D black-blood image. Our results show that the wall thickness measured from 2mm-thick images was overestimated, especially in the carotid artery, which is associated with a larger obliqueness angle. This result underscores the advantage of the 3D isotropic acquisition technique in wall thickness measurement, especially in more tortuous vessels.

ABSTRACTObjective:Bladder wall thickness (BWTh) measurements and Nerve Growth Factor (NGF) /creatinine (Cr) values, as noninvasive tools, were found to predict daytime voiding problems in children with overactive bladder (OAB). The goal of this research was to examine if bladder wall thickness together with urine NGF/Cr could be a clinical utility in treatment outcome of OAB in children.Patients and Methods:A total of 60 children with OAB, (Group 1; n=40) and healthy normal controls (Group 2; n=20), aged 6-14 years old were involved in this prospective study. Children were evaluated with detailed history and physical examination, including neurologic examination, and were asked to complete a self-reported questionnaire and a 3-day bladder diary with the aid of their parents. Uroflowmetry was performed in all cases. Urinary nerve growth factor levels were measured by the ELISA and BWTh was measured trans-abdominally by one uro-radiologist specialized in pediatric ultrasonography. Urinary NGF levels were normalized by urinary creatinine levels and compared among all subgroups. Children with OAB received urotherapy as first line treatment at least for three months. 18 children refractory to urotherapy received anticholinergic therapy defined as group 3.Results:The median age of the study group was 10 (range 6 to 16). After urotherapy, 22 children had similar BWTh and NGF/Cr values compared to controls. (2.75 ± 1.15; 2.40 ± 1.00 mm; p=0.86 and 1.02 ± 0.10; 0.78 ± 0.15; p=0.12, respectively). After anticholinergic treatment, BWTh levels (2.25 ± 0.90; 2.40 ± 1.00 mm; p=0.94) and NGF/Cr values (0.95 ± 0.10; 0.78 ± 0.15; p=0.42, respectively) had no significantly difference compared to controls (Group 2).In receiver operating characteristic analysis, bladder wall thickness was found to have sensitivity of 85% and specificity of 84.2% (3,20 AUC, 913; 95 %) and NGF/Cr had sensitivity of 90% and specificity of 92.1% (1,595; AUC, 947; 95 %) in predicting treatment outcome in children with OAB.Conclusions:Bladder wall thickness measurements and NGF/Cr values, as noninvasive tools, could guide outcomes in the treatment of children with overactive bladder.