Differences in bone histomorphometry between White postmenopausal women with and without atypical femoral fracture after long-term bisphosphonate therapy

Bone histomorphometric endpoints in transilial biopsies may be associated with an increased risk of atypical femoral fracture (AFF) in patients with osteoporosis who take antiresorptives, including bisphosphonates (BPs). One way to test this hypothesis is to evaluate bone histomorphometric endpoints in age-, gender-, and treatment time-matched patients who either had AFF or did not have AFF. In this study, we performed transiliac bone biopsies in 52 White postmenopausal women with (n = 20) and without (n = 32) AFFs, all of whom had been treated for osteoporosis continuously with alendronate for 4-17 yr. Despite the matched range of treatment duration (4-17 yr), AFF patients received alendronate for significantly longer time (10.7 yr) than non-AFF patients (8.0 yr) (P = .014). Bone histomorphometric endpoints reflecting microstructure and turnover were assessed in cancellous, intracortical, and endocortical envelopes from transilial biopsy specimens obtained from BP-treated patients 3-6 mo after AFF and from non-AFF patients with similar age-, gender-, and range of BP treatment duration. However, in both cancellous and intracortical envelopes, AFF patients had significantly lower wall thickness (W.Th) and higher osteoclast surface (Oc.S/BS) than non-AFF patients. In addition, AFF patients had significantly higher eroded surface (ES/BS) only in the intracortical envelope. None of the dynamic variables related to bone formation and turnover differed significantly between the groups. In conclusion, in the ilium of BP-treated patients with osteoporosis, AFF patients have lower thickness of superficial bone (lower W.Th) of the cancellous and cortical envelopes than non-AFF patients. AFF and non-AFF patients have a similar bone turnover rate in the ilium. Furthermore, in this population, as in previous work, AFF is more likely to occur in BP-treated patients with longer treatment duration.

Where is the gap after a 90 W/4 s very-high-power short-duration ablation of atrial fibrillation?: Association with the left atrial-pulmonary vein voltage and wall thickness

Background

Although pulmonary vein isolation (PVI) for atrial fibrillation (AF) utilizing radiofrequency (RF) applications with a very high-power and short-duration (vHPSD) has shortened the procedure time, the determinants of pulmonary vein (PV) gaps in the first-pass PVI and acute PV reconnections are unclear.

Methods

An extensive encircling PVI was performed with the QDOT MICRO catheter with a vHPSD (90 W-4 s) in 30 patients with AF (19 men, 64 ± 10 years). The association of the PV gap sites (first-pass PVI failure, acute PV reconnections [spontaneous reconnections or dormant conduction provoked by adenosine triphosphate] or both) with the left atrial (LA) wall thickness and LA bipolar voltage on the PVI line and ablation-related parameters were assessed.

Results

PV gaps were observed in 29 (6%) of 480 segments (16 segments per patient) in 17 patients (56%). The PV gaps were associated with the LA wall thickness, bipolar voltage, and the number of RF points (LA wall thickness, 2.5 ± 0.5 vs. 1.9 ± 0.4 mm, p < .001; bipolar voltage, 2.59 ± 1.62 vs. 1.34 ± 1.14 mV, p < .001; RF points, 6 ± 2 vs. 4 ± 2, p = .008) but were not with the other ablation-related parameters. Receiver operating characteristic curves yielded that an LA wall thickness ≥2.3 mm and bipolar voltage ≥2.40 mV were determinants of PV gaps with an area under the curve of 0.82 and 0.73, respectively.

Conclusions

The LA voltage and wall thickness on the PV-encircling ablation line were highly associated with PV gaps using the 90 W/4 s-vHPSD ablation.

A flexible modulated pesticide release platform through poly(urethane-urea) microcapsules: effect of different crosslinkers compositions

BACKGROUND

Polymeric microcapsules (MCs) have become an important issue and have attracted increasing attention because of their tunable physical and chemical properties. Diverse shell structures can confer multiple properties on MCs.

RESULTS

Different polyols (1,4-butanediol and glycerin) and polyamines (triethylenetetramine and isophorondiamine) were selected as crosslinkers to obtain emamectin benzoate (EB)-loaded poly(urethane-urea) MCs (PU-MCs) by interfacial polymerization. The four obtained PU-MCs showed sphericity with different degrees of smoothness on their surfaces, and displayed a uniform size distribution ranging from 500 to 700 nm. Moreover, transmission electron microscopy showed that the shell thickness was roughly uniform, and was greatly influenced by the type and structure of the crosslinker. GI-MCs, prepared using glycerin and isophorondiamine, had the largest shell thickness. GT-MCs, obtained using glycerin and triethylenetetramine, had the highest encapsulation efficiency and drug-loading content, and BT-MCs, obtained using mixtures of 1,4-butanediol and triethylenetetramine, had the fastest release behavior. Thermogravimetric analysis revealed that the greater the degree of shell crosslinking, the higher decomposition temperature and the greater the thermal stability. A BT-MC suspension had the lowest viscosity and contact angle with the best wettability. Bioassay experiments showed that BT-MCs exhibited good insecticidal activity against Plutella xylostella larvae with a half-maximal lethal concentration of 4.19 mg/L. Furthermore, a BT-MC suspension showed good thermal and light stability, with potential applications in minimizing the toxicity of EB through sustained release.

CONCLUSION

Various properties of EB-loaded PU-MCs were modulated through simple selection of different polyols and polyamines during fabrication, which might have an important role in constructing the pesticide delivery system and improving pesticide utilization. © 2024 Society of Chemical Industry.

Unveiling the Inner Structure of Micrometric Hollow Polymeric Fibers Using Synchrotron X-Ray Nanotomography

In this study, a novel application of synchrotron X-ray nanotomography based on high-resolution full-field transmission X-ray microscopy for characterizing the structure and morphology of micrometric hollow polymeric fibers is presented. By employing postimage analysis using an open-source software such as Tomviz and ImageJ, various key parameters in fiber morphology, including diameter, wall thickness, wall thickness distribution, pore size, porosity, and surface roughness, were assessed. Electrospun polycaprolactone fibers with micrometric diameters and submicrometric features with induced porosity via gas dissolution foaming were used to this aim. The acquired synchrotron X-ray nanotomography data were analyzed using two approaches: 3D tomographic reconstruction and 2D radiographic projection-based analysis. The results of the combination of both approaches demonstrate unique capabilities of this technique, not achievable by other available techniques, allowing for a full characterization of the internal and external morphology and structure of the fibers as well as to obtain valuable qualitative insights into the overall fiber structure.

Early vascular damage in retinal microcirculation in arterial hypertension: the Czech post-MONICA study

Retinal microcirculation reflects retinal perfusion abnormalities and retinal arterial structural changes at relatively early stages of various cardiovascular diseases. Wall-to-lumen ratio (WLR) may represent the earliest step in hypertension-mediated organ damage.Our objective was to compare functional and structural parameters of retinal microcirculation in a randomly selected urban population sample, in hypertensive and normotensive individuals.

DESIGN AND METHOD

A total of 398 randomly selected individuals from an urban population aged 25-65 years, residing in Pilsen, Czech Republic, were screened for major cardiovascular risk factors. Retinal microcirculation was assessed using scanning laser Doppler flowmetry, with data evaluable in 343 patients. Complete data were available for 342 individuals divided into four groups based on blood pressure and control status of hypertension: normotensive individuals ( n  = 213), treated controlled hypertensive individuals ( n  = 30), treated uncontrolled hypertensive individuals ( n  = 26), and newly detected/untreated hypertensive individuals ( n  = 73).

RESULTS

There was a tendency to higher wall thickness in treated but uncontrolled hypertensive patients (compared to normotensive and treated controlled hypertensive individuals). WLR was significantly increased in treated but uncontrolled hypertensive patients as well as in individuals with newly detected thus untreated hypertension or in patients with known but untreated hypertension. There was no difference in WLR in treated, controlled hypertensive patients compared with normotensive individuals.

CONCLUSION

Our results show that an increased WLR, reflecting early vascular damage, was found in newly detected individuals with hypertension and in untreated hypertensive patients, reflecting early hypertension-mediated vascular damage. Early initiation of hypertension treatment may be warranted.

Up-to-Date Diagnostic CT Standards for Acute Appendicitis: Wall Thickness and Intraluminal Fluid Thickness

Acute appendicitis is a prevalent condition that requires accurate and timely diagnosis and management to avoid potential complications. Classically, the diagnosis of appendicitis is made using the appendicular outer-to-outer wall diameter. In this study, we examined the sensitivity and specificity of computed tomography (CT) scans for diagnosing acute appendicitis using wall thickness and lumen thickness rather than diameter. This study included data from 350 patients who presented to the emergency department with clinically suspected acute appendicitis. All patients underwent a CT scan, and 62 radiologically positive patients underwent surgery. A radiological diagnosis was made using the conventional outer-to-outer wall diameter with a cut-off of 6 mm for a positive diagnosis. These 62 positive CT scans were reviewed and compared with surgical results. The study showed that a threshold of 2.25 mm for appendicular lumen thickness is an excellent diagnostic tool for acute appendicitis, demonstrating a high sensitivity of 96.4% and a lower specificity of 67%. In contrast, 1.6 mm wall thickness indicates acute appendicitis, with 81.8% sensitivity and 84% specificity. However, the wall thickness remains inferior to the conventionally used measurement of 6.75 mm for appendicular diameter, with a sensitivity of 87.5% and a specificity of 100%.

Role of Multidetector Computed Tomography in Differentiation of Benign and Malignant Cavitary Lung Lesions With a Histopathological Correlation: A Retrospective Cross-Sectional Study

Introduction Cavitary lung disease has a wide range of differential diagnoses, which include both benign and malignant lesions. Imaging differentiation of benign from malignant cavitary lesions has always been a challenge due to overlapping imaging findings. The present study describes the most accurate multidetector computed tomography (MDCT) findings that could help in differentiating benign from malignant conditions in correlation with the histopathological reports. Methods This retrospective study was carried out on diagnosed cases of cavitary lung lesions on MDCT from January 2022 to February 2023. We evaluated the number of cavitary lung lesions, their location with respect to lung segment/lobe, the maximum diameter of the largest lesion, the maximum wall thickness of the largest cavity, and additional findings associated with these lesions. Measurements of the maximum wall thickness were plotted on a graph. Statistical analysis was done, and a receiver operating characteristic curve (ROC) was calculated to find the accurate cut-off wall thickness for malignant and non-malignant lesions. These findings were then correlated with the histopathological report. Results A review of the MDCT scans of 47 patients was done; 30 (63.8%) of those were male with a mean age of 47.93±14.68 (SD) years while 17 (36.2%) were female with a mean age of 52.53 ±18.38 (SD) years. Out of 47 patients, 27 (57.4%) had benign lesions and 20 (42.5%) had malignant lesions. Significant differences (p<0.05) were found between benign and malignant lesions while comparing the averages of maximum wall thickness (8.1 mm and 14.5 mm, respectively) and the irregular inner margin of the largest cavitary lesions. The presence of consolidation and centrilobular nodules correlated significantly (p<0.05) with the benign nature of cavitary lung lesions. The maximum cut-off wall thickness was <6 mm and >17 mm for the differentiation of benign from malignant lung lesions, respectively. Conclusions The maximum wall thickness and irregular inner margin of cavitary lung lesions was a good indicator for the differentiation of benign and malignant etiologies on MDCT while consolidation and centrilobular nodules favoured the benign etiology more.

Effects of Processing Method and Parameters on the Wall Thickness of Gas-Projectile-Assisted Injection Molding Pipes

Gas-Projectile-Assisted Injection Molding (G-PAIM) is a new injection molding process derived from the Gas-Assisted Injection Molding (GAIM) process by introducing a projectile to it. In this study, the short-shot method and the overflow method of both the G-PAIM and GAIM processes were experimentally compared and investigated in terms of the wall thickness of the pipes and its uniformity. The results showed that the wall thickness of the G-PAIM molded pipe was thinner and more uniform than that of the GAIM molded pipe, and the wall thickness of the pipe molded by the Gas-Projectile-Assisted Injection Molding Overflow (G-PAIM-O) process was the most uniform. For the G-PAIM-O process, the influence of processing parameters, including melt temperature, gas injection delay time, gas injection pressure, melt injection pressure and mold temperature, on the wall thickness and uniformity of the G-PAIM-O pipes were studied via the single-factor experimental method. It was found that the effects of gas injection delay time and gas injection pressure on the wall thickness of the G-PAIM-O pipes were relatively significant. The wall thickness of the pipes increased with the increase in gas injection delay time and decreased with the increase in gas injection pressure. The melt temperature, melt injection pressure and mold temperature had little effect on the wall thickness of the G-PAIM-O pipes. In general, the wall thickness uniformity of the G-PAIM-O pipes was slightly affected by these processing parameters.

Processing of Low-Density HGM-Filled Epoxy-Syntactic Foam Composites with High Specific Properties for Marine Applications

A solution casting approach is used to create hollow glass microsphere (HGM)-filled epoxy-syntactic foam composites (e-SFCs) by varying the concentrations of HGM in epoxy according to different particle sizes. Density analysis is used to investigate the impact of concentration and particle size regularity on the microstructure of e-SFCs. It was observed that e-SFCs filled with an HGM of uniform particle sizes exhibit a reduction in density with increasing HGM concentration, whereas e-SFCs filled with heterogeneous sizes of HGM exhibit closeness in density values regardless of HGM concentration. The variation in e-SFC density can be related to HGM packing efficiency within e-SFCs in terms of concentration and particle size regularity. The particle size with lowest true density of 0.5529 g/cm³, experimental density of 0.949 g/cm³ and tensile strength of 55.74 MPa resulted in e-SFCs with highest specific properties of 100.81 (MPa·g/cm³), with a 35.1% increase from the lowest value of 74.64 (MPa·g/cm³) at a true density of 0.7286 g/cm³, experimental density of 0.928 g/cm³ and tensile strength of 54.38 MPa. The e-SFCs' theoretical density values were obtained. The variance in theoretical and experimental density values provides a thorough grasp of packing efficiency and inter-particle features.

An Investigation of the Constructional Design Components Affecting the Mechanical Response and Cellular Activity of Electrospun Vascular Grafts

Cardiovascular disease is anticipated to remain the leading cause of death globally. Due to the current problems connected with using autologous arteries for bypass surgery, researchers are developing tissue-engineered vascular grafts (TEVGs). The major goal of vascular tissue engineering is to construct prostheses that closely resemble native blood vessels in terms of morphological, mechanical, and biological features so that these scaffolds can satisfy the functional requirements of the native tissue. In this setting, morphology and cellular investigation are usually prioritized, while mechanical qualities are generally addressed superficially. However, producing grafts with good mechanical properties similar to native vessels is crucial for enhancing the clinical performance of vascular grafts, exposing physiological forces, and preventing graft failure caused by intimal hyperplasia, thrombosis, aneurysm, blood leakage, and occlusion. The scaffold's design and composition play a significant role in determining its mechanical characteristics, including suturability, compliance, tensile strength, burst pressure, and blood permeability. Electrospun prostheses offer various models that can be customized to resemble the extracellular matrix. This review aims to provide a comprehensive and comparative review of recent studies on the mechanical properties of fibrous vascular grafts, emphasizing the influence of structural parameters on mechanical behavior. Additionally, this review provides an overview of permeability and cell growth in electrospun membranes for vascular grafts. This work intends to shed light on the design parameters required to maintain the mechanical stability of vascular grafts placed in the body to produce a temporary backbone and to be biodegraded when necessary, allowing an autologous vessel to take its place.

Influence of acetabular cup thickness on seating and primary stability in total hip arthroplasty

Insufficient primary stability of acetabular hip cups is a complication resulting in early cup loosening. Available cup designs vary in terms of wall thickness, potentially affecting implant fixation. This study investigated the influence of different wall thicknesses on the implantation process and the resulting primary stability using excised human acetabula. Implantations were performed using a powered impaction device providing consistent energy with each stroke. Two different wall thicknesses were compared in terms of seating progress, polar gap remaining after implantation, bone-to-implant contact area, cup deflection, and lever out moment. Thin-walled cups showed higher lever out resistance (p < 0.001) and smaller polar gaps (p < 0.001) with larger bone contact toward the dome of the cup (p < 0.001) compared to thick-walled cups. Small seating steps at the end of the impaction process were observed if a high number of strokes were needed to seat the cup (p = 0.045). A high number of strokes led to a strain release of the cup during the final strokes (p = 0.003). This strain release is indicative for over-impaction of the cup associated with bone damage and reduced primary stability. Adequate cup seating can be achieved with thin-walled cups with lower energy input in comparison to thicker ones. Thin-walled cups showed improved primary stability and enable implantation with lower energy input, reducing the risk of over-impaction and bone damage. Additional strokes should be avoided as soon as no further seating progress has been observed.

Anatomical Characteristics and Variation Mechanisms on the Thick-Walled and Dwarfed Culm of Shidu Bamboo (Phyllostachys nidularia f. farcta)

Stable culm variants are valuable and important material for the study of culm development in bamboo plants. However, to date, there are few reports on the mechanism of variation of these bamboo variants. Phyllostachys nidularia f. farcta (Shidu bamboo) is a bamboo variant with stable phenotypes such as a dwarf culm with a thickened wall. In this study, we systematically investigated the cytological characteristics and underlying mechanism of morphological variation in culms of this variant using anatomical, mathematical statistical, physiological, and genomic methods. The anatomical observation and statistical results showed that the lateral increase of ground tissue in the inner layer of culm wall and the enlargement of vascular bundles are the anatomical essence of the wall thickening of Shidu bamboo; the limited elongation of fiber cells and the decrease in the number of parenchyma cells longitudinally are probably the main causes of the shortening of its internodes. A number of genes involved in the gibberellin synthesis pathway and in the synthesis of cell wall components are differentially expressed between the variant and its prototype, Ph. nidularia, and may play an important role in determining the phenotype of internode shortening in Shidu bamboo. The decrease in gibberellin content and the content of the major chemical components of the cell wall of Shidu bamboo confirmed the results of the above transcriptome. In addition, the variation in culm morphology in Shidu bamboo had little effect on the volume of the culm wall of individual internodes, suggesting that the decrease in the total number of internodes and the decrease in dry matter content (lignin, cellulose, etc.) may be the main factor for the sharp decline in culm biomass of Shidu bamboo.

Maximal Wall Thickness Measurement in Hypertrophic Cardiomyopathy: Biomarker Variability and its Impact on Clinical Care

OBJECTIVES

The aim of this study was to define the variability of maximal wall thickness (MWT) measurements across modalities and predict its impact on care in patients with hypertrophic cardiomyopathy (HCM).

BACKGROUND

Left ventricular MWT measured by echocardiography or cardiovascular magnetic resonance (CMR) contributes to the diagnosis of HCM, stratifies risk, and guides key decisions, including whether to place an implantable cardioverter-defibrillator (ICD).

METHODS

A 20-center global network provided paired echocardiographic and CMR data sets from patients with HCM, from which 17 paired data sets of the highest quality were selected. These were presented as 7 randomly ordered pairs (at 6 cardiac conferences) to experienced readers who report HCM imaging in their daily practice, and their MWT caliper measurements were captured. The impact of measurement variability on ICD insertion decisions was estimated in 769 separately recruited multicenter patients with HCM using the European Society of Cardiology algorithm for 5-year risk for sudden cardiac death.

RESULTS

MWT analysis was completed by 70 readers (from 6 continents; 91% with >5 years' experience). Seventy-nine percent and 68% scored echocardiographic and CMR image quality as excellent. For both modalities (echocardiographic and then CMR results), intramodality inter-reader MWT percentage variability was large (range -59% to 117% [SD ±20%] and -61% to 52% [SD ±11%], respectively). Agreement between modalities was low (SE of measurement 4.8 mm; 95% CI 4.3 mm-5.2 mm; r = 0.56 [modest correlation]). In the multicenter HCM cohort, this estimated echocardiographic MWT percentage variability (±20%) applied to the European Society of Cardiology algorithm reclassified risk in 19.5% of patients, which would have led to inappropriate ICD decision making in 1 in 7 patients with HCM (8.7% would have had ICD placement recommended despite potential low risk, and 6.8% would not have had ICD placement recommended despite intermediate or high risk).

CONCLUSIONS

Using the best available images and experienced readers, MWT as a biomarker in HCM has a high degree of inter-reader variability and should be applied with caution as part of decision making for ICD insertion. Better standardization efforts in HCM recommendations by current governing societies are needed to improve clinical decision making in patients with HCM.

Association between Neonatal Intakes and Hyperglycemia, and Left Heart and Aortic Dimensions at 6.5 Years of Age in Children Born Extremely Preterm

Survivors of extremely preterm birth (gestational age < 27 weeks) have been reported to exhibit an altered cardiovascular phenotype in childhood. The mechanisms are unknown. We investigated associations between postnatal nutritional intakes and hyperglycemia, and left heart and aortic dimensions in children born extremely preterm. Postnatal nutritional data and echocardiographic dimensions at 6.5 years of age were extracted from a sub-cohort of the Extremely Preterm Infants in Sweden Study (EXPRESS; children born extremely preterm between 2004-2007, n = 171, mean (SD) birth weight = 784 (165) grams). Associations between macronutrient intakes or number of days with hyperglycemia (blood glucose > 8 mmol/L) in the neonatal period (exposure) and left heart and aortic dimensions at follow-up (outcome) were investigated. Neonatal protein intake was not associated with the outcomes, whereas higher lipid intake was significantly associated with larger aortic root diameter (B = 0.040, p = 0.009). Higher neonatal carbohydrate intake was associated with smaller aorta annulus diameter (B = -0.016, p = 0.008). Longer exposure to neonatal hyperglycemia was associated with increased thickness of the left ventricular posterior wall (B = 0.004, p = 0.008) and interventricular septum (B = 0.004, p = 0.010). The findings in this study indicate that postnatal nutrition and hyperglycemia may play a role in some but not all long-lasting developmental adaptations of the cardiovascular system in children born extremely preterm.

Deep learning based fully automatic segmentation of the left ventricular endocardium and epicardium from cardiac cine MRI

Background

The segmentation of cardiac medical images is a crucial step for calculating clinical indices such as wall thickness, ventricular volume, and ejection fraction.

Methods

In this study, we introduce a method named LsUnet that combines multi-channel, fully convolutional neural network, and annular shape level-set methods for efficiently segmenting cardiac cine magnetic resonance (MR) images. In this method, the multi-channel deep learning algorithm is applied to train the segmentation task to extract the left ventricle (LV) endocardial and epicardial contours. Next, the segmentation contours from the multi-channel deep learning method are incorporated into a level-set formulation, which is dedicated explicitly to detecting annular shapes to assure the segmentation's accuracy and robustness.

Results

The proposed automatic approach was evaluated on 95 volumes (total 1,076 slices, ~80% as for training datasets, ~20% 2D as for testing datasets). This combined multi-channel deep learning and annular shape level-set segmentation method achieved high accuracy with average Dice values reaching 92.15% and 95.42% for LV endocardium and epicardium delineation, respectively, in comparison to the reference standard (the manual segmentation).

Conclusions

A novel method for fully automatic segmentation of the LV endocardium and epicardium from different MRI datasets is presented. The proposed workflow is accurate and robust compared to the reference and other state-of-the-art methods.

Optimal choice of OSEM and SD reconstruction algorithms in CZT SPECT for hypertrophic cardiomyopathy patients

BACKGROUND

The spectrum dynamics (SD) algorithm is a cardiac reconstruction algorithm of D-SPECT, which improves spatial resolution compared with the ordered-subsets expectation maximization (OSEM) algorithm. We evaluated the wall thickness and left ventricular (LV) volume in patients with hypertrophic cardiomyopathy (HCM) using the SD algorithm.

METHODS

In a phantom study, the myocardial wall was scanned with varying wall thicknesses (10-40 mm). In the clinical study, 30 and 27 normal and HCM patients underwent myocardial perfusion imaging.

RESULTS

In a phantom study, LV volume using the SD algorithm was increased by thickening the wall of the phantom. In the clinical study, the wall thickness and LV volume of OSEM and SD algorithms showed a difference between HCM and normal groups. The wall thickness using OSEM and SD algorithms were 19.4 ± 2.0 and 16.7 ± 1.5 mm in patients with normal, and 27.9 ± 4.9 and 21.8 ± 2.6 mm in patients with HCM.

CONCLUSION

The SD algorithm in cases of HCM may not be able to correctly assess wall thickness and LV volume. Our study suggests that the OSEM is more suitable in cases of HCM than the SD algorithm.

Tailored ablation index for pulmonary vein isolation according to wall thickness within the ablation circle

BACKGROUND

Ablation index (AI), a novel lesion quality marker, includes contact force, time, and power of radiofrequency (RF) application, but not regional variation in wall thickness within the wide antral catheter ablation (WACA) circle. This study explored the relationships among AI target value, atrial wall thickness, and gap formation within the WACA circle in patients with paroxysmal atrial fibrillation (PAF).

METHODS

We evaluated 102 consecutive patients (mean age, 65 ± 9 years) with PAF who underwent AI-guided WACA for ipsilateral pulmonary vein isolation (PVI). Each WACA circle was subdivided into eight segments, and overall 7143 RF applications were delivered, including 125 gaps in PVI ablation lines. For each RF tag within the ablation circle, we collected data on ablation lesion depth surrogates (time of application, delivery power, impedance drop, average contact force, force-time integral [FTI], and AI) and left atrial wall thickness measured by multidetector computer tomography scanning.

RESULTS

The anterior and roof walls were the thickest segments of the ablation circle, in which 85.8% of gaps concentrated, while the posterior and inferior walls were the thinnest. Gap formation was significantly associated with FTI, AI, wall thickness, FTI/wall thickness, and AI/wall thickness. AI/wall thickness had the highest predictive value for gap formation, with a cutoff of 195.6 au/mm for effective ablation.

CONCLUSIONS

In AI-guided PVI of PAF, AI/wall thickness by normalizing myocardial thickness variation along the WACA circle was a strong predictor of gap formation, with a target of 195.6 au/mm appearing suitable for effective ablation.

A comparative study of the normal oesophageal wall thickness based on 3-dimensional, 4-dimensional, and cone beam computed tomography

BACKGROUND

The study aimed to compare normal oesophageal wall thickness based on 3-dimensional computed tomography (3DCT), 4-dimensional computed tomography (4DCT) and cone beam computed tomography (CBCT).

METHODS

Contrast-enhanced 3DCT, 4DCT, and CBCT scans were acquired from 50 patients with lung cancer or metastatic lung cancer. The outer oesophageal wall was manually contoured on each 3DCT, the maximum intensity projection of 4DCT (4DCTMIP) the end expiration phase of 4DCT (4DCT50) (the end expiration phase of 4DCT) and the CBCT data sets. The average wall thicknesses were measured (defined as R3DCT, R50, RMIP, and RCBCT).

RESULTS

Whether for thoracic or for intra-abdominal segments, there were no significant differences between R3DCT and R50, but significant differences between R3DCT and RMIP, R3DCT and RCBCT. For upper and middle oesophagus, RCBCT were larger than RMIP. There was no significant difference between upper and middle segments on 3DCT, 4DCT, and CBCT. Intra-abdominal oesophageal wall thickness was greater than that of thoracic oesophagus. There were no differences between upper and lower, and middle and lower oesophagus on CBCT.

CONCLUSION

Our findings indicate normal oesophageal wall thickness differed along the length of oesophagus whatever it was delineated on 3DCT, 4DCT (4DCT50 and 4DCTMIP) or CBCT. It is reasonable to use uniform criterion to identify normal esophageal wall thickness when delineating gross tumor volume on 3DCT and 4DCT50, the same is true of delineating internal gross tumor volume on 4DCTMIP or CBCT images for lower and intra-abdominal oesophagus. But, in spite of using contrast-enhanced scanning, relatively blurred boundary on the CBCT images is noteworthy, especially for upper and middle thoracic esophagus.

LOCALLY ADAPTIVE HALF-MAX METHODS FOR AIRWAY LUMEN-AREA AND WALL-THICKNESS AND THEIR REPEAT CT SCAN REPRODUCIBILITY

Quantitative computed tomography (CT)-based characterization of bronchial metrics is increasingly being used to investigate chronic obstructive pulmonary disease (COPD)-related phenotypes. Automated methods for airway measurements benefit large multi-site studies by reducing cost and subjectivity errors. Critical challenges for CT-based analysis of airway morphology are related to location of lumen and wall transitions in the presence of varying scales and intensity-contrasts from proximal to distal sites. This paper introduces locally adaptive half-max methods to locate airway lumen and wall transitions and compute cross-sectional lumen area and wall-thickness. Also, the method uses a consistency analysis of wall-thickness to avoid adjoining-structure-artifacts. Experimental results show that computed bronchial measures at individual anatomic airway tree locations are repeat CT scan reproducible with intra-class correlation coefficient (ICC) values exceeding 0.9 and 0.8 for lumen-area and wall-thickness, respectively. Observed ICC values for derived morphologic measures, e.g., lumen-area compactness (ICC>0.67) and tapering (ICC>0.47) are relatively lower.

Effect of Wall Thickness on Stress-Strain Response and Buckling Behavior of Hollow-Cylinder Rubber Fenders

In this study, the effect of wall thickness (15–25 mm) on the stress–strain response of hollow-cylinder rubber fenders were investigated by conducting monotonic compression tests. It was found that a progressive increase in lateral bending deformation was observed during monotonic compression. Simultaneously, the extent of the lateral deflection decreased notably with an increasing wall thickness. From the experimental results, the fact is accepted that buckling occurred in the tested fender due to the fact that the ratio of the height to the wall thickness was higher than four in all of the considered cases. Moreover, an s-shape profile appeared in the stress–strain curves, which became clearer as the wall thickness was reduced from 25 to 15 mm. To assess the performance of fenders objectively, an energy-effectiveness index, CER, was introduced to quantify the energy absorption capacity of the fender. From the experimental observations, it was inferred that the contact area of the folded inner surface of the fender produced under compression generated an additional reaction force and affected the shape of the stress–strain curve since the measured load consisted of two reaction forces: one caused by the self-contact area, and the other resulted from the compression-bending deformation that occurred in the side wall of the fender. To examine this assertion, a finite element analysis (FEA) was conducted and confirmed the effect of the reaction force on the sensitivity of the s-shape characteristic of the stress–strain curve. Finally, a polynomial regression was conducted and the calculated results based on the fourth-degree stress polynomial function correlated very well with the measured stress–strain curves.

Multiparametric Echocardiography Scores for the Diagnosis of Cardiac Amyloidosis

OBJECTIVES

This study aimed to investigate the accuracy of a broad range of echocardiographic variables to develop multiparametric scores to diagnose CA in patients with proven light chain (AL) amyloidosis or those with increased heart wall thickness who had amyloid was suspected. We also aimed to further characterize the structural and functional changes associated with amyloid infiltration.

BACKGROUND

Cardiac amyloidosis (CA) is a serious but increasingly treatable cause of heart failure. Diagnosis is challenging and frequently unclear at echocardiography, which remains the most often used imaging tool.

METHODS

We studied 1,187 consecutive patients evaluated at 3 referral centers for CA and analyzed morphological, functional, and strain-derived echocardiogram parameters with the aim of developing a score-based diagnostic algorithm. Cardiac amyloid burden was quantified by using extracellular volume measurements at cardiac magnetic resonance.

RESULTS

A total of 332 patients were diagnosed with AL amyloidosis and 339 patients with transthyretin CA. Concentric remodeling and strain-derived parameters displayed the best diagnostic performance. A multivariable logistic regression model incorporating relative wall thickness, E wave/e' wave ratio, longitudinal strain, and tricuspid annular plane systolic excursion had the greatest diagnostic performance in AL amyloidosis (area under the curve: 0.90; 95% confidence interval: 0.87 to 0.92), whereas the addition of septal apical-to-base ratio yielded the best diagnostic accuracy in the increased heart wall thickness group (area under the curve: 0.80; 95% confidence interval: 0.85 to 0.90).

CONCLUSIONS

Specific functional and structural parameters characterize different burdens of CA deposition with different diagnostic performances and enable the definition of 2 scores that are sensitive and specific tools with which diagnose or exclude CA.

Wall thickness and mucous cell distribution in the rabbit large intestine

To achieve a better understanding of rabbit large intestinal functions, such as production of hard and soft feces and cecal fermentation, knowledge of the intestinal wall structure is essential. However, such knowledge is far from complete. Therefore, the aims of this study were to measure the thickness of the wall and its constituent layers and describe distribution of mucous cells in each segment of the large intestine in New Zealand White rabbits. Results showed that the cecum had the thinnest entire wall throughout the large intestine, and the fusus coli and rectum had a thicker entire wall in comparison to the cecum, the first segment of the proximal colon, the second segment of the proximal colon, and the distal colon. Moreover, the thickness of the mucosa in the fusus coli and that of the inner and outer layers of the tunica muscularis in the rectum were greater than that of the other segments. Mucous cells in the mucosa were the fewest in the cecum and most numerous in the fusus coli. This study provides detailed knowledge of the wall thickness and distribution of mucous cells in the large intestine of the rabbit. These findings are important for improving our understanding of rabbit intestinal physiology and pathology.

Detailed comparison between the wall thickness and voltages in chronic myocardial infarction

BACKGROUND

The relationship between the local electrograms (EGMs) and wall thickness (WT) heterogeneity within infarct scars has not been thoroughly described. The relationship between WT and voltages and substrates for ventricular tachycardia (VT) was examined.

METHODS

In 12 consecutive patients with myocardial infarction and VT, WT, defined by a multidetector computed tomography, and voltage were compared. In multicomponent EGMs, amplitudes of both far- and near-field components were manually measured, and the performance of the three-dimensional-mapping system automatic voltage measurement was assessed.

RESULTS

Of 15 748 points acquired, 2677 points within 5 mm of the endocardial surface were analyzed. In total, 909 (34.0%) multicomponent EGMs were identified; 785 (86.4%) and 883 (97.1%) were distributed in the WT less than 4 and 5 mm, respectively. Far-field EGM voltages increased linearly from 0.14 mV (0.08-0.28 mV) in the WT: 0 to 1 mm to 0.70 mV (0.43-2.62 mV) in the WT: 4 to 5 mm (ρ = 0.430; P < 0.001), and a significant difference was demonstrated between any two WT-groups (P ≤ 0.001). In contrast, near-field EGM voltages varied from 0.27 mV (0.11-0.44 mV) in the WT: 0 to 1 mm to 0.29 mV (0.17-0.53 mV) in the WT: 4 to 5 mm with a poorer correlation (ρ = 0.062, P = 0.04). The proportion of points where the system automatically measured the voltage on near-field EGMs increased from less than 10% in areas of WT: 4 to 5 mm to 50% in areas less than 2 mm. Of 21 VTs observed, seven hemodynamically stable VTs were mapped and terminated in WT: 1 to 4 mm area.

CONCLUSIONS

Although far-field voltages gradually increase with the WT, near-field does not. The three-dimensional-mapping system preferentially annotates the near-field components in thinner areas (center of the scar) and the far-field component in thicker areas when building a voltage map. Critical sites of VT are distributed in WT: 1 to 4 mm areas.

Assessing regional left ventricular thickening dysfunction and dyssynchrony via personalized modeling and 3D wall thickness measurements for acute myocardial infarction

BACKGROUND

Existing clinical diagnostic and assessment methods could be improved to facilitate early detection and treatment of cardiac dysfunction associated with acute myocardial infarction (AMI) to reduce morbidity and mortality.

PURPOSE

To develop 3D personalized left ventricular (LV) models and thickening assessment framework for assessing regional wall thickening dysfunction and dyssynchrony in AMI patients.

STUDY TYPE

Retrospective study, diagnostic accuracy.

SUBJECTS

Forty-four subjects consisting of 15 healthy subjects and 29 AMI patients.

FIELD STRENGTH/SEQUENCE

1.5T/steady-state free precession cine MRI scans; LGE MRI scans.

ASSESSMENT

Quantitative thickening measurements across all cardiac phases were correlated and validated against clinical evaluation of infarct transmurality by an experienced cardiac radiologist based on the American Heart Association (AHA) 17-segment model.

STATISTICAL TEST

Nonparametric 2-k related sample-based Kruskal-Wallis test; Mann-Whitney U-test; Pearson's correlation coefficient.

RESULTS

Healthy LV wall segments undergo significant wall thickening (P < 0.05) during ejection and have on average a thicker wall (8.73 ± 1.01 mm) compared with infarcted wall segments (2.86 ± 1.11 mm). Myocardium with thick infarct (ie, >50% transmurality) underwent remarkable wall thinning during contraction (thickening index [TI] = 1.46 ± 0.26 mm) as opposed to healthy myocardium (TI = 4.01 ± 1.04 mm). For AMI patients, LV that showed signs of thinning were found to be associated with a significantly higher percentage of dyssynchrony as compared with healthy subjects (dyssynchrony index [DI] = 15.0 ± 5.0% vs. 7.5 ± 2.0%, P < 0.01). Also, a strong correlation was found between our TI and left ventricular ejection fraction (LVEF) (r = 0.892, P < 0.01), and moderate correlation between DI and LVEF (r = 0.494, P < 0.01).

DATA CONCLUSION

The extracted regional wall thickening and DIs are shown to be strongly correlated with infarct severity, therefore suggestive of possible practical clinical utility.

LEVEL OF EVIDENCE

2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;49:1006-1019.

A Study of Quantifying Thickness of Ferromagnetic Pipes Based on Remote Field Eddy Current Testing

Remote Field Eddy Current Testing (RFECT) has broad applications in ferromagnetic pipe testing due to the same testing sensitivity to inner and outer wall defects. However, how to quantify wall thickness in the RFECT of pipes is still a big problem. According to researchers’ studies, a linear relationship exists between the wall thickness, permeability and conductivity of a pipe and the phase of the RFECT signal. Aiming to quantify wall thickness by using this linear function, it is necessary to further study the effects of pipe permeability and conductivity on the phase of the RFECT signal. When the product value of the permeability and the conductivity of a pipe remains constant, the univariate analysis and Finite Element Analysis (FEA) are employed to analyze the variations among the phase of the RFECT signal caused by different couples of permeability and conductivity. These variations are calibrated by using a nonlinear fitting method. Moreover, Multi-Frequency Eddy Current Testing (MFECT) is applied to inverse the permeability and conductivity of a pipe to compensate for the quantification analysis of wall thickness. The methods proposed in this paper are validated by analyzing the simulation signals and can improve the practicality of RFECT of ferromagnetic pipes.

Attenuation profile matching: An accurate and scan parameter-robust measurement method for small airway dimensions in low-dose CT scans

PURPOSE

The dimensions of small airways with an internal diameter of less than 2-3 mm are important biomarkers for the evaluation of pulmonary diseases, such as asthma and chronic obstructive pulmonary disease (COPD). The resolution limitations of CT systems, however, have remained a barrier to be of use for determining the small airway dimensions. We present a novel approach, called the attenuation profile matching (APM) method, which allows for the accurate determination of the small airway dimension while being robust to varying CT scan parameters.

METHOD

For generating the synthetic attenuation profiles of an airway, we acquired and employed the point spread functions of a CT system by calculating its convolution with numerical airway models with varying wall thicknesses. The dimensions of a given airway were determined as per the numerical model yielding minimum error between the measured and the synthetic attenuation profiles across the airway.

RESULTS

In a phantom study with airway tubes, the APM method proved to be highly accurate in determining airway wall dimensions. The measurement error for the smallest tube (0.6 mm thickness, 3 mm diameter) was merely 0.02 mm (3.3%) in wall thickness and 0.17 mm (5.6%) in lumen diameter. In a pilot clinical test, the APM method was able to distinguish the airway wall thicknesses of COPD cases (1.16 ± 0.23 mm) from those of normal subjects (0.6 ± 0.18 mm), while the measurements using the full width at half maximum method substantially overlapped (1.45 ± 0.32 mm vs. 1.28 ± 0.30 mm, respectively) and were barely distinguishable from each other.

CONCLUSION

Our proposed APM method has the potential to overcome the resolution limitations of current CT systems and accurately determine the small airway dimensions in COPD patients.

Arterial stiffening is a heritable trait associated with arterial dilation but not wall thickening: a longitudinal study in the twins UK cohort

Aims

Vascular ageing is characterized by arterial stiffening, dilation, and arterial wall thickening. We investigated the extent to which these changes are related and their heritability during 5 year follow-up in the Twins UK cohort.

Methods and results

Carotid-femoral pulse wave velocity (PWVcf), carotid diameter, carotid distensibility, and carotid intima-media thickness (IMT) were measured in 762 female twins (mean age 57.9 ± 8.6 years) at two time-points over an average follow-up of 4.9 ± 1.5 years. Magnetic resonance imaging (MRI) was performed in a sub-sample of 38 women to measure aortic pulse wave velocity (PWVaorta), diameter, and wall thickness. Heritability of changes in arterial wall properties was estimated using structural equation modelling. Annual increases in PWVcf, carotid diameter, distensibility, and IMT were 0.139 m/s, 0.028 mm, -0.4 kPa-1, and 0.011 mm per year, respectively. In regression analysis, predictors of progression in PWVcf included age, mean arterial pressure (MAP), and heart rate (HR) at baseline, and progression in MAP, HR, and body mass index (BMI). Predictors of progression in IMT included progression in MAP, BMI, and triglyceride levels. Progression of PWV and distensibility correlated with progression in carotid diameter but not with IMT. Heritability of progression of PWVcf, diameter, and IMT was 55%, 21%, and 8%, respectively. In a sub-sample of women that underwent MRI, aortic wall thickness increased by 0.19 mm/year, but aortic wall thickening was not correlated with an increase in lumen diameter or PWVaorta.

Conclusion

Arterial stiffening, as measured by PWVcf, and dilation are heritable but independent of arterial wall thickening. Genetic and cardiovascular risk factors contribute differently to progression of PWV and IMT.

Vascular narrowing in pulmonary arterial hypertension is heterogeneous: rethinking resistance

In idiopathic pulmonary arterial hypertension (PAH), increased pulmonary vascular resistance is associated with structural narrowing of small (resistance) vessels and increased vascular tone. Current information on pulmonary vascular remodeling is mostly limited to averaged increases in wall thickness, but information on number of vessels affected and internal diameter decreases for vessels of different sizes is limited. Our aim was to quantify numbers of affected vessels and their internal diameter decrease for differently sized vessels in PAH in comparison with non‐PAH patients. Internal and external diameters of transversally cut vessels were measured in five control subjects and six PAH patients. Resistance vessels were classified in Strahler orders, internal diameters 13 μm (order 1) to 500 μm (order 8). The number fraction, that is, percentage of affected vessels, and the internal diameter fraction, that is, percentage diameter of normal diameter, were calculated. In PAH, not all resistance vessels are affected. The number fraction is about 30%, that is, 70% of vessels have diameters not different from vessels of control subjects. Within each order, the decrease in diameter of affected vessels is variable with an averaged diameter fraction of 50–70%. Narrowing of resistance vessels is heterogeneous: not all vessels are narrowed, and the decrease in internal diameters, even within a single order, vary largely. This heterogeneous narrowing alone cannot explain the large resistance increase in PAH. We suggest that rarefaction could be an important contributor to the hemodynamic changes.

Three-dimensional Integrated Functional, Structural, and Computational Mapping to Define the Structural "Fingerprints" of Heart-Specific Atrial Fibrillation Drivers in Human Heart Ex Vivo

BACKGROUND

Structural remodeling of human atria plays a key role in sustaining atrial fibrillation (AF), but insufficient quantitative analysis of human atrial structure impedes the treatment of AF. We aimed to develop a novel 3-dimensional (3D) structural and computational simulation analysis tool that could reveal the structural contributors to human reentrant AF drivers.

METHODS AND RESULTS

High-resolution panoramic epicardial optical mapping of the coronary-perfused explanted intact human atria (63-year-old woman, chronic hypertension, heart weight 608 g) was conducted during sinus rhythm and sustained AF maintained by spatially stable reentrant AF drivers in the left and right atrium. The whole atria (107×61×85 mm³) were then imaged with contrast-enhancement MRI (9.4 T, 180×180×360-μm³ resolution). The entire 3D human atria were analyzed for wall thickness (0.4-11.7 mm), myofiber orientations, and transmural fibrosis (36.9% subendocardium; 14.2% midwall; 3.4% subepicardium). The 3D computational analysis revealed that a specific combination of wall thickness and fibrosis ranges were primarily present in the optically defined AF driver regions versus nondriver tissue. Finally, a 3D human heart-specific atrial computer model was developed by integrating 3D structural and functional mapping data to test AF induction, maintenance, and ablation strategies. This 3D model reproduced the optically defined reentrant AF drivers, which were uninducible when fibrosis and myofiber anisotropy were removed from the model.

CONCLUSIONS

Our novel 3D computational high-resolution framework may be used to quantitatively analyze structural substrates, such as wall thickness, myofiber orientation, and fibrosis, underlying localized AF drivers, and aid the development of new patient-specific treatments.

ENCAPSULATION OF EGGS BY MARINE GASTROPODS: EFFECT OF VARIATION IN CAPSULE FORM ON THE VULNERABILITY OF EMBRYOS TO PREDATION

Representatives of many plant and animal taxa enclose their embryos within some form of protective structure. Inter- and intraspecific differences in the morphology of these egg coverings may have profound effects on the development and survival of encapsulated embryos, yet in many taxa little is known about the causes or potential consequences of this variation. Comparisons of capsule morphology among populations of the rocky shore gastropod, Nucella emarginata, revealed significant variation in the thickness of capsule walls, the only barrier separating developing embryos from the external environment. Laboratory experiments demonstrated that thicker-walled capsules were more resistant to predation by a co-occurring isopod, Gnorimosphaeroma oregonense, than were thinner-walled capsules. Control experiments confirmed that these differences in vulnerability were not caused by differences in the palatability of the capsule wall or attractiveness of the capsule contents. The actual mechanism by which thick-walled capsules differentially protect developing embryos remains unclear, although decreased vulnerability of thick-walled capsules to these isopods may simply result from increased handling time by predators. Subtle differences in capsule morphology thus appear to have substantial effects on the survival of encapsulated embryos. Hence, predators may have played an important role in selecting for the production of thick-walled capsules among populations of N. emarginata.

A Thin Left Atrial Antral Wall Around the Pulmonary Vein Reflects Structural Remodeling by Atrial Fibrillation and is Associated with Stroke

PURPOSE

Circumferential pulmonary (PV) vein isolation (CPVI) is the most important treatment strategy for atrial fibrillation (AF). While understanding left atrial wall thickness around PVs (PVWT) prior to catheter ablation is important, its clinical implications are not known. This study aimed to evaluate PVWT characteristics according to underlying disease and to identify associations between PVWT and reconnections of PV potentials (PVPs) in redo ablation.

MATERIALS AND METHODS

In 28 patients who underwent redo-AF ablation, PVWT and reconnected PVPs were evaluated at 12 sites (1-12 o'clock) around each PV. Clinical characteristics including stroke and CHA₂DS₂-VASc scores were analyzed according to the PVWT.

RESULTS

The PVWT was thicker in males than females (p<0.001) and in those with diabetes (p=0.045) or heart failure (p=0.002) than in those without. Patients with strokes or high CHA₂DS₂-VASc scores (≥3) had significantly thinner PVWTs than those without strokes or low CHA₂DS₂-VASc scores (p<0.001). In redo-ablation, reconnected PVPs were detected in 60 (53.6%) of 112 PVs, and the PVs were thicker (p<0.001) and had more reconnected PVs (p=0.009) than right PVs. A PVWT of >0.6 mm predicted PV reconnections with a sensitivity of 76.7% and specificity of 52.2% with an area under the curve of 0.695.

CONCLUSION

Thick PVWs were associated with diabetes and heart failure, and also showed significant inverse correlations with stroke and the CHA₂DS₂-VASc score. Thick PVWs were associated with reconnected PVPs after the CPVI, which were related to AF recurrence.

Computed Tomographic Airway Morphology in Chronic Obstructive Pulmonary Disease. Remodeling or Innate Anatomy?

Computed tomographic measures of central airway morphology have been used in clinical, epidemiologic, and genetic investigation as an inference of the presence and severity of small-airway disease in smokers. Although several association studies have brought us to believe that these computed tomographic measures reflect airway remodeling, a careful review of such data and more recent evidence may reveal underappreciated complexity to these measures and limitations that prompt us to question that belief. This Perspective offers a review of seminal papers and alternative explanations of their data in the light of more recent evidence. The relationships between airway morphology and lung function are observed in subjects who never smoked, implying that native airway structure indeed contributes to lung function; computed tomographic measures of central airways such as wall area, lumen area, and total bronchial area are smaller in smokers with chronic obstructive pulmonary disease versus those without chronic obstructive pulmonary disease; and the airways are smaller as disease severity increases. The observations suggest that (1) native airway morphology likely contributes to the relationships between computed tomographic measures of airways and lung function; and (2) the presence of smaller airways in those with chronic obstructive pulmonary disease versus those without chronic obstructive pulmonary disease as well as their decrease with disease severity suggests that smokers with chronic obstructive pulmonary disease may simply have smaller airways to begin with, which put them at greater risk for the development of smoking-related disease.

Automated Measurement of Blood Vessels in Tissues from Microscopy Images

The quantification of tunica media thickness in histological cross sections is a ubiquitous exercise in cardiopulmonary research, yet the methods for quantifying medial wall thickness have never been rigorously examined with modern image analysis tools. As a result, inaccurate and cumbersome manual measurements of discrete wall regions along the vessel periphery have become common practice for wall thickness quantification. The aim of this study is to introduce, validate, and facilitate the use of an improved method for medial wall thickness quantification. We describe a novel method of wall thickness calculation based on image skeletonization and compare its results to those of common techniques. Using both theoretical and empirical approaches, we demonstrate the accuracy and superiority of the skeleton-based method for measuring wall thickness while discussing its interpretation and limitations. Finally, we present a new freely available software tool, the VMI Calculator, to facilitate wall thickness measurements using our novel method. © 2016 by John Wiley & Sons, Inc.

Effect of Left Atrial Wall Thickness on Radiofrequency Ablation Success

INTRODUCTION

Radiofrequency (RF) ablation in thicker regions of the left atrium (LA) may require increased ablation energy in order to achieve effective transmural lesions. Consequently, many cases of recurrent atrial fibrillation (AF) postablation may be due to thicker-than-normal atrial tissue. The aim of this study was to test the hypotheses that patients with recurrent AF have thicker tissue overall and that electrical reconnection is more likely in regions of thicker tissue.

METHODS AND RESULTS

Retrospective analysis was performed on 86 CT images acquired preoperatively from a cohort of 119 patients who had undergone RF ablation for AF. Of these, 33 patients experienced recurrence of AF within 1 year of initial treatment and 29 returned for a repeat ablation. For each patient, LA wall thickness (LAWT) was measured from the images in 12 anatomical regions using custom software. Patients with recurrent AF had larger LAWT compared to successfully treated patients (1.6 ± 0.6 mm vs. 1.5 ± 0.5 mm, P < 0.001) and reconnection was found to be at regions of thicker tissue (1.6 ± 0.6 mm, P = 0.038) compared to nonreconnected regions (1.5 ± 0.5 mm). The superior right posterior wall of the LA was significantly related to both recurrence (P = 0.048) and reconnection (P = 0.014).

CONCLUSION

Increased LAWT has a small but significant effect on postablation recurrence and reconnection. Measures of LAWT may facilitate appropriate dosing of RF energy, but other factors will be critical in transmural lesion formation and ablation success.

Steady State Response Analysis of a Tubular Piezoelectric Print Head

In recent years, inkjet technology has played an important role in industrial materials printing and various sensors fabrication, but the mechanisms of the inkjet print head should be researched more elaborately. The steady state deformation analysis of a tubular piezoelectric print head, which can be classified as a plane strain problem because the radii of the tubes are considerably smaller than the lengths, is discussed in this paper. The geometric structure and the boundary conditions are all axisymmetric, so a one-dimensional mathematical model is constructed. By solving the model, the deformation field and stress field, as well as the electric potential distribution of the piezoelectric tube and glass tube, are obtained. The results show that the deformations are on the nanometer scale, the hoop stress is larger than the radial stress on the whole, and the potential is not linearly distributed along the radial direction. An experiment is designed to validate these computations. A discussion of the effect of the tubes' thicknesses on the system deformation status is provided.

Pulmonary arterial wall thickness in Eisenmenger Syndrome: Prospective, cross-sectional, controlled clinical trial

BACKGROUND

The aim of current study is to investigate echocardiographic pulmonary artery wall thickness (PAWT) association with angiocardiography, echocardiography, and biochemical findings and to demonstrate its predictive role in morbidity of disease.

METHOD

Nineteen patients with Eisenmenger Syndrome (ES) (13 females; a mean age of 12.0 ± 4.1 [min-max 4-17] years) and 24 (16 females; a mean age of 12.1 ± 4.3 [min-max 3-18 years]) healthy subjects as a control group were included in this prospective, cross-sectional, controlled clinical study between December, 2012 and December, 2013. PAWT were measured at the end of systole at the distal site of pulmonary valves at the parasternal short-axis. PAWT was compared with morbidity criteria of the disease such as functional class, pulmonary vascular resistance.

RESULTS

PAWT was higher in the patient group (P = 0.005) together with pulmonary arterial diameter (Z-score, P < 0.001), vena cava inferior diameter (P = 0.002), and right ventricular wall thickness (RVWT), while TAPSE was significantly lower (P = 0.002). PAWT was strongly positively correlated to RVWT (r = 0.893, P < 0.001) and moderate negatively correlated to TAPSE (r = 0.597; P < 0.011).

CONCLUSION

PAWT can be used as an additional parameter with other echocardiographic parameters in the follow-up of Eisenmenger Syndrome in children.

Contribution of Rare and Common Genetic Variants to Plasma Lipid Levels and Carotid Stiffness and Geometry: A Substudy of the Paris Prospective Study 3

BACKGROUND

We assess the contribution of common and rare putatively functional genetic variants (most of them coding) present on the Illumina exome Beadchip to the variability of plasma lipids and stiffness of the common carotid artery.

METHODS AND RESULTS

Measurements were obtained from 2283 men and 1398 women, and after filtering and exclusion of monomorphic variants, 32,827 common (minor allele frequency >0.01) and 68,770 rare variants were analyzed. A large fraction of the heritability of plasma lipids is attributable to variants present on the array, especially for triglycerides (fraction of variance attributable to measured genotypes: V(G)/V(p)=31.4%, P<3.1×10(-11)) and high-density lipoprotein cholesterol (V(G)/V(p)=26.4%, P<4.2×10(-12)). Plasma lipids were associated with common variants located in known candidate genes, but no implication of rare variants could be established. Gene sets for plasma lipids, blood pressure, and coronary artery disease were defined on the basis of recent meta-analyses of genome-wide association studies. We observed a strong association between the plasma lipids gene set and plasma lipid variables, but none of the 3 genome-wide association studies gene sets was associated with the carotid parameters. Significant V(G)/V(p) ratios were observed for external (14.5%, P<2.7×10(-5)) and internal diameter (13.4%, P<4.3×10(-4)), stiffness (12.5%, P<8.0×10(-4)), intima-media thickness (10.6%, P<7.9×10(-4)), and wall cross-sectional area (13.2%, P<2.4×10(-5)). A significant association was observed between the common rs2903692 polymorphism of the CLEC16A gene and the internal diameter (P<4.3×10(-7)).

CONCLUSIONS

These results suggest an involvement of CLEC16A, a gene that has been reported to be associated with immune disorders, in the modulation of carotid vasodilatation.

The impact of the bladder wall thickness on the outcome of the medical treatment using alpha-blocker of BPH patients with LUTS

OBJECTIVES

To evaluate whether the outcome of medical treatment with α 1 receptor blocker in Benign prostatic hyperplasia (BPH) patients with lower urinary tract symptoms (LUTS) is affected by the bladder wall thickness (BWT) Methods: A total of 125 male BPH patients with LUTS were enrolled. All patients were assessed using The International Prostatic Symptom Score (IPSS), prostate specific antigen (PSA), prostate volume, uroflowmetry, post voiding residual (PVR). BWT was measured by Trans-abdominal ultrasound, and patients were divided into two groups group 1 (patients with BWT <5 mm) and group 2 (patients with BWT ≥5 mm). The patients were reassessed after 2 months of treatment with α 1 receptor blocker (alfuzosin 10 mg). Clinical parameters were analyzed and compared between groups.

RESULTS

There were significant difference between both groups as regard IPSS, voiding symptoms, and storage symptoms (p = 0.005), (p = 0.010) and (p = 0.041) respectively. After medication, there were improvements in the total IPSS, voiding symptoms, storage symptoms, Qmax, PVR and Qol in both groups and these improvements were more effectively in (group 1) than (group 2) with statistically significant differences (p < 0.05).

CONCLUSION

BWT has positive correlation with the total IPSS, voiding symptoms subscores and storage symptoms subscores. The response to medical treatment is found statistically less in patients with BWT greater than 5 mm.

Stoichiometry, Length, and Wall Thickness Optimization of TiO2 Nanotube Array for Efficient Alcohol Sensing

The present study concerns development of an efficient alcohol sensor by controlling the stoichiometry, length, and wall thickness of electrochemically grown TiO2 nanotube array for its use as the sensing layer. Judicious variation of H2O content (0, 2, 10 and 100% by volume) in the mixed electrolyte comprising ethylene glycol and NH4F resulted into the desired variation of stoichiometry. The sensor study was performed within the temperature range of 27 to 250 °C for detecting the alcohols in the concentration range of 10-1000 ppm. The nanotubes grown with the electrolyte containing 2 vol % H2O offered the maximum response magnitude. For this stoichiometry, variation of corresponding length (1.25-2.4 μm) and wall thickness (19.8-9 nm) of the nanotubes was achieved by varying the anodization time (4-16 h) and temperatures (42-87 °C), respectively. While the variation of length influenced the sensing parameters insignificantly, the best response magnitude was achieved for ∼13 nm wall thickness. The underlying sensing mechanism was correlated with the experimental findings on the basis of structural parameters of the nanotubes.

Quantitative assessment of multiscale structural and functional alterations in asthmatic populations

Relationships between structural and functional variables in asthmatic lungs at local and global (or lobar) levels remain to be discovered. This study aims to investigate local alterations of structural variables [bifurcation angle, circularity, airway wall thickness (WT), and hydraulic diameter (Dh)] in asthmatic subjects, and their correlations with other imaging and pulmonary function test-based global and lobar metrics, including lung shape, air-trapping, regional volume change, and more. Sixty-one healthy subjects, and 67 nonsevere and 67 severe asthmatic subjects were studied. The structural variables were derived from computed tomography images at total lung capacity (TLC). Air-trapping was measured at functional residual capacity, and regional volume change (derived from image registration) was measured between functional residual capacity and TLC. The tracheal diameter and WT predicted by 61 healthy subjects were used to normalize the Dh and WT. New normalization schemes allowed for the dissociation of luminal narrowing and wall thickening effects. In severe asthmatic subjects, the alteration of bifurcation angle was found to be correlated with a global lung shape at TLC, and circularity was significantly decreased in the right main bronchus. While normalized WT increased especially in the upper lobes of severe asthmatic subjects, normalized Dh decreased in the lower lobes. Among local structural variables, normalized Dh was the most representative variable, because it was significantly correlated with alterations of functional variables, including pulmonary function test's data. In conclusion, understanding multiscale phenomena may help to provide guidance in the search for potential imaging-based phenotypes for the development and outcomes assessment of therapeutic intervention.

Adaptive optics assisted visualization of thickened retinal arterial wall in a patient with controlled malignant hypertension

Purpose

We aimed to visualize the retinal arterial wall thickness, assisted by noninvasive adaptive optics scanning laser ophthalmoscopy (AO-SLO).

Methods

The arterial wall thickness was measured and compared between one normal subject and one patient suffering from malignant hypertensive retinopathy.

Results

Increased arterial wall thickness was revealed with a newly developed AO-SLO system, in a retinal artery of 1-papilla diameter temporal inferior to the optic disc. The average wall thickness, with hypertension, was 18.7 μm, and the wall-to-lumen ratio was 0.44, both bigger than normal.

Conclusion

AO-SLO enabled us to evaluate the retinal wall thickness in the hypertensive patient. The arterial walls were thickened compared with normal. AO-SLO may facilitate future noninvasive study of arterial walls in human medicine.

Is there an association between asymmetry of carotid artery wall thickness (ACAWT) and cerebrovascular symptoms?

PURPOSE

Previous publications demonstrated that multi-detector-row computed tomography Angiography (MDCTA) can evaluate the carotid artery wall thickness (CAWT). The purpose of this work was to compare the asymmetry of CAWT between carotids in symptomatic and asymptomatic patients.

MATERIAL AND METHODS

Sixty consecutive symptomatic (males 44; median age 64) and 60 asymptomatic sex- and age-matched patients were analysed by using a 40-detector-row CT system. CAWT was calculated for both carotids in each patient and the ratio between the thicker CAWT and the contra-lateral was calculated to obtain the ACAWT index. Bland-Altman, logistic regression and receiver operating characteristic (ROC) curve analysis were calculated.

RESULTS

The Bland-Altman plot demonstrates a very good agreement between measurements with a mean difference value of 3.4% and 95% CI from -8% to 14.8%. The ACAWT was significantly different between symptomatic and asymptomatic patients (with a p value of 0.0001). The ROC area under the curve was 0.742 (p = 0.001). Logistic regression model indicated that ACAWT, CAWT, stenosis degree, and fatty plaques were independent variables associated with cerebrovascular symptoms (p value, respectively, 0.0108, 0.0231, 0.0002, and 0.013).

CONCLUSION

Results of our study indicated that the index of asymmetry in the CAWT might be used as a further parameter to stratify the risk of symptoms related to carotid artery.

Intestinal wall thickness detected by multidetector spiral computed tomography enterography predicts the disease severity of Crohn's disease

OBJECTIVE

Multidetector spiral computed tomography enterography (MSCTE) and ileocolonoscopy are used in evaluating inflammatory situation of Crohn's disease (CD) patients. The purpose of this study was to determine the disease severity of CD patients by combining the intestinal wall thickness by MSCTE with ileocolonoscopy.

MATERIAL AND METHODS

This retrospective study included 50 patients with terminal ileal CD. Diagnosis was confirmed based on clinical features, endoscopy, and pathology. Patients underwent both MSCTE and ileocolonoscopy. Ileal wall thickness was measured and the disease severity was evaluated by CD activity index (CDAI). Intestinal mucosal lesions were scored by the simple endoscopic score for CD (SES-CD).

RESULTS

Of the 50 patients with active terminal ileal CD, the comparison of scores between SES-CD and CDAI showed significant association with Spearman's rank correlation coefficient (p < 0.01). There were statistically significant correlation between the wall thickness and the SES-CD (p < 0.0001) as well as CDAI (p < 0.001), respectively, but no significant correlation between the wall thickness and the C-reactive protein (CRP) was found (p = 0.43). Moreover, we found that the wall thickness was preferential to predict the disease severity in the terminal ileal CD.

CONCLUSION

MSCTE, in combination with ileocolonoscopy, is reliable to identify disease severity in CD patients and provides more accurate information in the diagnosis and treatment.

Individual reference values for 2D echocardiographic measurements. The Stockholm - Umeå Study

OBJECTIVES

Improved reference values for 2D echocardiographic measurements are required, even when more recent echocardiographic technology is employed. In addition, it may be preferable to individualize reference values from age, gender and body characteristics of any subject.

DESIGN

A material of 180 healthy subjects was collected and investigated, aiming for an even distribution of sex and age (from 20 to 80 years of age; the Stockholm material). For atrial areas, material from another 216 healthy subjects with similar sex and age distribution was added (the Umeå material). The 2D measures determined were the left and right ventricular diameters in diastole, the left ventricular diameter in systole, the thickness of septum and posterior wall, the diameters of the aortic root (sinotubular junction) and the left atrium (all in parasternal view), together with the left and right ventricular diameters in diastole and left and right atrial areas in end-systole (apical four-chamber view). The width of the inferior vena cava (from subcostal view) was also determined.

RESULTS

Confidence intervals for females and males are presented for each of these measures. Multiple linear regression analyses with age, sex and measures of body characteristics as predictors were also performed, and for eight of the 12 measurements, such equations are presented.

CONCLUSIONS

It is possible to obtain more highly individualized reference values for these cardiac dimensions, which may clinically be a better way of distinguishing pathological states from normal states.

Effect of hyperbaric oxygen therapy on cerebral vasospasm: a vascular morphometric study in an experimental subarachnoid hemorrhage model

This study was undertaken to investigate the preventive or therapeutic effect of hyperbaric oxygen therapy (HBOT) on cerebral vasospasm following experimental subarachnoid hemorrhage (SAH). Twenty rabbits were assigned randomly to one of four groups. Animals in Group I were not subjected to SAH or sham operation (control group, n = 5). Animals in Group II were subjected to sham operation and received no treatment after the procedure (sham group, n = 5). Animals in Group III were subjected to SAH and received no treatment after SAH induction (SAH group, n = 5). Animals in Group IV were subjected to SAH and received five sessions of HBOT at 2.4 atmospheres absolute (ATA) for 2 h (treatment group, n = 5). Animals were euthanized by perfusion and fixation 72 h after procedures. Basilar artery vasospasm indices, arterial wall thicknesses, and cross-sectional luminal areas were evaluated. Statistical comparisons were performed using Kruskal-Wallis and Mann-Whitney U tests. Mean basilar artery vasospasm index in the treatment group was significantly smaller than in the SAH group. Mean basilar artery wall thickness in the treatment group was significantly smaller than in the SAH group. Mean basilar artery cross-sectional luminal area in the treatment group showed an increase relative to the SAH group, but this difference remained statistically insignificant. Our results demonstrated that repeated application of HBOT at 2.4 ATA for 2 h attenuated vasospastic changes such as increased vasospasm index and arterial wall thickness. HBOT is thus a promising candidate for SAH-induced vasospasm. Further studies are needed to evaluate maximal effect and optimal application regimen.

The normal growth of the tracheal wall in human foetuses

INTRODUCTION

Tracheal wall thickness is a substantial indicator in various pathological changes. The present study was performed to compile normative data and formulae for the tracheal wall thickness and volume at varying gestational age.

MATERIAL AND METHODS

Using anatomical dissection, digital image analysis and statistics a range of the wall thickness, proximal internal-to-external cross-sectional area ratio, and wall volume for the trachea in 73 spontaneously aborted human fetuses aged 14-25 weeks was examined.

RESULTS

No significant male-female differences were found. The values of tracheal wall thickness ranged from 0.36 ±0.01 mm for the 14-week group to 1.23 ±0.17 mm for the 25-week group of gestation, according to the linear function y = -0.823 + 0.083 × age ± 0.087. The tracheal lumen rate, expressed as the proximal internal-to-external cross-sectional area ratio, decreased from 42.61 ±1.11% to 26.78 ±4.95%, according to the function y = 62.239 - 1.487 × age ±3.119. The tracheal wall volume rose from 16.28 ±4.18 mm(3) in fetuses aged 14 weeks to 269.22 ±29.26 mm(3) in fetuses aged 25 weeks, according to the quintic function y = 0.000052 × age(4.894).

CONCLUSIONS

The tracheal wall parameters show no sexual dimorphism. The tracheal wall grows linearly in its length, and according to a quintic function in its volume. A relative decrease in the tracheal lumen at the expense of an increase in both the wall thickness and wall volume of the trachea is found during gestation.

Cigarette smoking and airway wall thickness on CT scan in a multi-ethnic cohort: the MESA Lung Study

BACKGROUND

Autopsy studies show that smoking contributes to airway wall hyperplasia and narrowing of the airway lumen. Studies of smoking and airway measures on computed tomography (CT) scan are limited to case-control studies of measures that combine airway lumen and wall thickness.

OBJECTIVES

We hypothesized that cumulative cigarette smoking would be associated with increased airway wall thickness in a large, population-based cohort.

METHODS

The Multi-Ethnic Study of Atherosclerosis enrolled participants age 45-84 years from the general population. Smoking history was assessed via standardized questionnaire items; current smoking was confirmed in half the cohort with cotinine. Airway lumen and wall thickness were measured in two dimensions in posterior basal segmental bronchi on cardiac-gated CT scans. Analyses were adjusted for age, gender, genetic ancestry, education, height, weight, asthma history, particulate matter, scanner type, and scanner current.

RESULTS

Half of the 7898 participants had smoked and 14% were current smokers. Pack-years of smoking were associated with thicker airway walls (mean increase 0.002 mm per ten pack-years [95% CI: 0.00002, 0.004] p = 0.03). Current smoking was associated with narrower airway lumens (mean decrease -0.11 mm [95% CI: -0.2, -0.02] p = 0.02). There was no evidence that either association was modified by genetic ancestry, and findings persisted among participants without clinical disease.

CONCLUSIONS

Long-term cigarette smoking was associated with subclinical increases in wall thickness of sub-segmental airways whereas current smoking was associated with narrower airway lumen diameters. Smoking may contribute to airway wall thickening prior to the development of overt chronic obstructive pulmonary disease.

A three-dimensional tagged magnetic resonance imaging study

BACKGROUND

Regional performance of the hypertrophied left ventricle (LV) in hypertrophic cardiomyopathy (HCM) is still incompletely characterized with studies variably reporting that the hypertrophied myocardium is hypokinetic, akinetic, or has normal function. Different imaging modalities (M-mode or two-dimensional echocardiography) and methods of analysis (fixed or floating frame of reference for wall motion analysis) yield different results. We assessed regional function in terms of systolic wall thickening and shortening and related these parameters to end-diastolic thickness using tagged magnetic resonance imaging and the three-dimensional volume-element approach.

METHODS AND RESULTS

In 17 patients with HCM and 6 healthy volunteers, four parallel short-axis images with 12 radial tags and two mutually orthogonal long-axis images with four parallel tags were obtained at end diastole and end systole. After the LV endocardial and epicardial borders were traced, three-dimensional volume elements were constructed by connecting two matched planar segments in two adjacent short-axis image planes, accounting for translation, twist, and long-axis shortening. A total of 72 such volume elements encompassed the entire LV. From each of these elements, end-diastolic thickness and systolic function (fractional thickening and circumferential shortening) were calculated. The average end-diastolic thickness was 15.8 +/- 4.2 mm in patients with HCM, which was significantly greater than that in healthy subjects (8.6 +/- 2.1 mm, P < .001). Fractional thickening was significantly less in patients with HCM than in healthy subjects (0.31 +/- 0.22 versus 0.56 +/- 0.23, P < .001). There was a highly significant inverse correlation between fractional thickening and end-diastolic thickness that was independent of the type of hypertrophy or age group. Similar inverse relations were observed between circumferential shortening and end-diastolic wall thickness.

CONCLUSIONS

The myocardium in patients with HCM is heterogeneously thickened and the fractional thickening and circumferential shortening of the abnormally thickened myocardium are reduced compared with healthy subjects. The decrease in fractional thickening and shortening is inversely related to the local thickness.