True Diameter Research Articles

Functional tumor diameter measurement with molecular breast imaging: development and clinical application

Purpose: Molecular breast imaging (MBI) is used clinically to visualize the uptake of 99mTc-sestamibi in breast cancers. Here, we use Monte Carlo simulations to develop a methodology to estimate tumor diameter in focal lesions and explore a semi-automatic implementation for clinical data. Methods: A validated Monte Carlo simulation of the GE Discovery NM 750b was used to simulate >75,000 unique spherical/ellipsoidal tumor, normal breast, and image acquisition conditions. Subsets of this data were used to 1) characterize the dependence of the full-width at half-maximum (FWHM) of a tumor profile on tumor, normal breast, and acquisition conditions, 2) develop a methodology to estimate tumor diameters, and 3) quantify the diameter accuracy in a broad range of clinical conditions. Finally, the methodology was implemented in patient images and compared to diameter estimates from physician contours on MBI, mammography, and ultrasound imaging. Results: Tumor profile FWHM was determined be linearly dependent on tumor diameter but independent of other factors such as tumor shape, uptake, and distance from the detector. A linear regression was used to calculate tumor diameter from the FWHM estimated from a background-corrected profile across a tumor extracted from a median-filtered single-detector MBI image, i.e., diameter = 1.2 mm + 1.2 × FWHM, for FWHM ≥ 13 mm. Across a variety of simulated clinical conditions, the mean error of the methodology was 0.2 mm (accuracy), with >50% of cases estimated within 1-pixel width of the truth (precision). In patient images, the semi-automatic methodology provided the longest diameter in 94% (60/64) of cases. The estimated true diameters, for oval lesions with homogeneous uptake, differed by ± 5 mm from physician measurements. Conclusion: This work demonstrates the feasibility of accurately quantifying tumor diameter in clinical MBI, and to our knowledge, is the first to explore its implementation and application in patient data.

Estimating Fundamental Parameters of Celestial Objects Using Some Observational Parameters

Abstract: Far away objects seem to appear smaller than the original size. There is confusion about the concept of the perceived size of objects based on distance. In this work, new mathematical formulae are given for the apparent size of objects in both isoscele view and scalene view in terms of absolute distance. The new formulae for the temperature of black bodies and the true diameter of luminous objects are obtained from the apparent size relations. The present study will highlight the diameter of luminous objects and the expression for the temperature of black bodies. Keywords: Apparent size, Appearance, Isoscele view, Scalene view.

Clinical characteristics and misdiagnosis of spontaneous isolated superior mesenteric artery dissection

BackgroundSpontaneous isolated superior mesenteric artery (SMA) dissection (SISMAD) is a rare disease with a potentially fatal pathology. Due to the lack of specificity of clinical characteristics and laboratory tests, misdiagnosis and missed diagnosis are often reported. Therefore, the aim of this study was to investigate the clinical characteristics and misdiagnosis of SISMAD.MethodsIn a registry study from January 2013 to December 2020, 110 patients with SISMAD admitted to the First Affiliated Hospital of Wenzhou Medical University were enrolled. Descriptive methods were used to analyse clinical characteristics, laboratory data, diagnostic method or proof, misdiagnosed cases, plain computed tomography (CT) findings and dissection features. To study the relationship between dissection features and treatment modality, the selected patients were classified into the conservative group (n = 71) and the non-conservative group (n = 39). The Chi-square test and Student’s t-test were used to compare the conservative and non-conservative groups.ResultsOne hundred ten patients with SISMAD, including 100 (90.9%) males and 10 (9.1%) females, with a mean age of 52.4 ± 7.6 years, were enrolled in the study. Relevant associated comorbidities included a history of hypertension in 43 cases (39.1%), smoking in 46 cases (41.8%), and alcohol consumption in 34 cases (30.9%). One hundred four patients (94.5%) presented with abdominal pain. Abnormalities in the C-reactive protein lever, white blood cells count and D-dimer lever were the 3 most common abnormal findings. There were 32 misdiagnosis or missed diagnosis. Fourteen cases were misdiagnosed because of insufficient awareness. Twelve cases were misdiagnosed because of disease features. Twenty cases were misdiagnosed as SMA embolism. Among them, There were 15 cases of Yun type IIb SISMAD. Sixty-six patients underwent plain CT. The maximum SMA diameter was 12.1 (11.3–13.1) mm, and the maximum SMA diameter was located on the left renal vein (LRV) plane in 68.2% of cases. Dissection features observed on contrast-enhanced CT (CECT), CT angiography (CTA), or digital subtraction angiography (DSA) showed that there were 70 cases (63.6%) of Yun type IIb SISMAD, the maximum SMA diameter was 13.0 ± 2.4 mm, the location of the maximum SMA diameter was on the LRV plane in 64.5% of cases, and 7.3% of cases were complicated with intestinal obstruction, including bowel necrosis in 3.6% of cases. There were differences between the conservative group and non-conservative groups in the residual true lumen diameter or degree of true lumen stenosis and the presence of intestinal obstruction or bowel necrosis (all P < 0.05).ConclusionFor SISMAD, misdiagnosis and missed diagnosis were usually caused by insufficient awareness and disease features. SISMAD should be considered in the differential diagnosis of patients presenting with unexplained abdominal pain, especially males, patients in the 5th decade of life, patients with hypertension, and patients with an enlarged SMA diameter or a maximum SMA diameter located on the LRV plane on plain CT. Mesenteric CTA or CECT should be recommended for the investigation of these conditions.

Elucidating the Role of the AFX2 Endograft in Endovascular Treatment of Aortic Pathology

The purpose of this study is to elucidate the role of the AFX2 platform in the endovascular treatment of aortic pathology. All procedures by a single surgeon resulting in implantation of a bifurcated unibody stent graft were reviewed retrospectively. Indications for selection of the AFX2 endograft in each case were evaluated. Aortic anatomy was determined via review of pre-operative computed tomography (CT) scans. Cumulative event probabilities for endoleak, reintervention, and mortality were estimated. Patient and procedural details were described using mean, standard deviation, medians, and interquartile range (IQR). Kaplan-Meier survival analysis estimated freedom from mortality and reintervention. Cumulative incidence probabilities were calculated as one minus the Kaplan-Meier estimator. Between March 2018 and December 2020, the author (NN) used 142 aortic endografts in 142 patients. Of these, 46 (32.4%) were AFX2 endografts and the remaining were modular bifurcated devices, predominantly Medtronic Endurant II and Terumo Treo. No AFX-Strata or AFX-Duraply devices were placed. Amongst the patients who received an AFX2, mean age was 71.3 +/- 9.8years with 84.8% male. Median operative time was 116 (86-166) min, with contrast dose of 79 (41-120) milliliters and fluoroscopy time of 12 (8.6-18) min. Overall, 78.3% (n=36) of AFX2 devices were placed in aortas with maximum true lumen diameter <5.0cm. Median postoperative follow-up was 1.7years (IQR 1.0-2.4years), with a maximum follow-up of 3.6years. There was 1 patient lost to follow-up at 5months. The 2-year incidence of type II endoleak, reintervention, and all-cause mortality was 12.7% (95% confidence interval CI, 0-29.6%), 2.2% (95% CI, 0-6.3%), and 11.3% (95% CI, 0.1-2.1.2%), respectively. There were no type I or III endoleaks. The AFX2 endograft plays a safe and effective role in treatment of infrarenal aortic pathologies that may be otherwise more technically challenging for traditional modular, bifurcated devices.

Atrial Embolization after a Transcatheter Mitral Valve Replacement

Atrial Embolization after a Transcatheter Mitral Valve Replacement

A Novel Solution for Distal Dilation of Chronic Dissection After Repair Involving Visceral Branches: The Road Block Strategy.

AimNotwithstanding that unprecedented endovascular progress has been achieved in recent years, it remains unclear what is the best strategy to preserve the blood perfusion of abdominal visceral arteries and promote positive aortic remodeling in patients with distal dilatation of chronic aortic dissection in abdominal visceral part (CADAV) after aortic repair. The present study developed a Road Block Strategy (RBS) to solve this conundrum.Methods and ResultsThis prospective single-center clinical study included patients suffering from symptomatic distal dilatation of CADAV after aortic repair treated with RBS from January 2015 to December 2019 and followed up regularly for at least 2 years. Stent grafts were implanted first to cover distal tears and expand the true lumen. Device embolization was performed to induce proximal and distal segmental false lumen thrombosis (FLT) apart from the level of the ostia of vital branches. Successful RBS was performed in 13 patients. Significant differences were found in maximum true lumen diameter (p < 0.05), blood flow area in false lumen (FL) (p < 0.001), and the ratio of blood lumen to FL area (p < 0.05) between the pre-procedure and the latest follow-up results. No aortic rupture, vital branches occlusion, thoracic and abdominal pain, or death occurred during hospitalization and follow-up.ConclusionsOur findings suggest that RBS is feasible in treating distal dilatation of chronic aortic dissection after prior proximal repair, inducing false lumen thrombosis, preventing deterioration of aortic dissection, and maintaining the patency of abdominal visceral arteries.

Incidence of Prosthesis-Patient Mismatch in Valve-in-Valve with a Supra-Annular Valve.

Transcatheter aortic valve replacement (TAVR) for a degenerated surgical bioprosthesis (valve-in-valve [ViV]) has become an established procedure. Elevated gradients and patient-prosthesis mismatch (PPM) have previously been reported in mixed TAVR cohorts. We analyzed our single-center experience using the third-generation self-expanding Medtronic Evolut R prosthesis, with an emphasis on the incidence and outcomes of PPM. This is a retrospective analysis of prospectively collected data from our TAVR database. Intraprocedural and intrahospital outcomes are reported. Eighty-six patients underwent ViV-TAVR with the Evolut R prosthesis. Mean age was 75.5 ± 9.5 years, 64% were males. The mean log EuroScore was 21.6 ± 15.7%. The mean time between initial surgical valve implantation and ViV-TAVR was 8.8 ± 3.2 years. The mean true internal diameter of the implanted surgical valves was 20.9 ± 2.2 mm. Post-AVR, 60% had no PPM, 34% had moderate PPM, and 6% had severe PPM. After ViV-TAVR, 33% had no PPM, 29% had moderate, and 39% had severe PPM. After implantation, the mean transvalvular gradient was reduced significantly from 36.4 ± 15.2 to 15.5 ± 9.1 mm Hg (p < 0.001). No patient had more than mild aortic regurgitation after ViV-TAVR. No conversion to surgery was necessary. Estimated Kaplan-Meier survival at 1 year for all patients was 87.4%. One-year survival showed no significant difference according to post-ViV PPM groups (p = 0.356). ViV-TAVR using a supra-annular valve resulted in low procedural and in-hospital complication rates. However, moderate or severe PPM was common, with no influence on short-term survival. PPM may not be a suitable factor to predict survival after ViV-TAVR.

Laser accessories: surgical fibers, strippers, cleavers, and protective glasses.

This review provides most recent findings and developments relating to surgical laser fibers, strippers, cleavers, and protective glasses. The smallest core diameter that can be used with Holmium:YAG lasers is 200 μm. Smaller core diameter fibers can be used with the Thulium fiber laser and offer better flexibility and lower risk of fracture, at the risk of greater burnback effect. Misleading discrepancies between the true diameter of laser fibers and their packaging labels must be considered. Fiber tip degradation from the burnback occurs within few minutes, thus questioning the need for time-consuming fiber tip reprocessing with fiber strippers and special cleaving tools. This shortcoming also applies to instrument-protecting ball-tip fibers. Cleavage of fiber tips through their protective jackets ('coated tips') is a cheaper alternative for instrument protection, additionally offering better visual control of the fiber tip. Third-generation side-firing greenlight laser fibers are still prone to rapid deterioration. Laser eyewear does not seem necessary for Holmium:YAG applications, whereas laser-specific protective glasses should be worn for greenlight laser applications. With better understanding of laser accessories, practicing urologists may tailor their practice to reach optimal efficacy and safety for Holmium:YAG, Thulium fiber laser and Greenlight laser applications.

Choosing an appropriate size valve for transcatheter pulmonary valve implantation in a native right ventricle outflow tract.

Introduction:Transcatheter pulmonary valve implantation has been an effective treatment for dysfuntional right ventricular tract outflow tract (RVOT). Defining a landing zone before the intervention is crucial in patients with native RVOT. Improper sizing and undefined landing zone will lead to embolization.Methods:It is a retrospective observational study from August 2020 to December 2020 in native RVOT. Three patients who had significant Right ventricle dilatation were analyzed. The multi-slice computed tomography (MSCT) with magnetic resonance imaging and angiography data of all patients before the procedure were analyzed. All patients underwent an angiogram in the same sitting, before the procedure to assess the landing zone, valve diameter as well as the risk for coronary compression. We chose a valve based on valve area 23%–25% more than the area at the waist during balloon sizing.Results:All three patients underwent successful valve implantation. Valve sizes used were 27.5 mm in one and 32 mm in the other two. The mean RVOT gradient postprocedure was 11.5 mm Hg and pre procedure was 43 mmHg. There were no complications during the procedure or at a mean follow-up of 3.6 months.Conclusion:The balloon sizing gives the true narrowest diameter in comparison with MSCT, and increasing this area by 23%–25% will give the appropriate valve size for successful implantation.

Study of Vertebral Artery Dissection by Ultrasound Superb Microvascular Imaging Based on Deep Neural Network Model.

To assess the diagnostic value of ultrasound Superb Microvascular Imaging (SMI) and versus Doppler ultrasound (TCD) for microvascular structure and aerodynamic changes in vertebral artery dissection (VAD). In this paper, we firstly simulate the process of clinician recognition of vertebral artery dissection and propose a combination of a priori shape information of vertebral artery dissection and deep folly convolutional networks (DFCNs) for IVUS. In this paper, 15 patients with vertebral artery dissection confirmed by SMI, digital subtraction angiography (DSA), or computed tomography angiography (CTA) from 2020 to 2021 were selected, and the true and false lumen diameters, peak systolic flow velocity (PSV), end-diastolic flow velocity (EDV) and PSV, EDV, and plasticity index (PI) of the intracranial vertebral artery were measured. Among the 15 patients with VAD, 4 (27%, 4/15) had trauma-induced secondary vertebral artery entrapment and 11 (73%, 11/15) had spontaneous entrapment without a clear cause. According to the structural characteristics of the vessels, there were 11 cases (73%, 11/15) of double-lumen, intramural hematoma, and vertebral artery dissection aneurysm, and 11 cases (73%, 11/15) of V1 segment. SMI not only provides an objective assessment of the vascular morphology and aerodynamic changes in VAD but also, in combination with TCD, can further determine the opening of the traffic branches in the posterior circulation, providing reliable information for the early diagnosis and treatment of microvascular dissection of the vertebral artery.

ПЕРИАПИКАЛЬНЫЙ АБСЦЕСС СО СВИЩОМ, ОСЛОЖНЕННЫЙ ВЕРХНЕЧЕЛЮСТНЫМ СИНУСИТОМ (КЛИНИЧЕСКИЙ СЛУЧАЙ)

Subject. Chronic odontogenic maxillary sinusitis is an inflammatory disease of the mucous membrane of the maxillary sinus caused by an odontogenic infection. According to foreign sources, this disease occurs in 14-20% of the world's population. Sinusitis of odontogenic etiology account for up to 40% of all inflammatory diseases of the maxillary sinus. Biofilm, the root cause of apical periodontitis and odontogenic sinusitis, is resistant to the isolated effects of most medications. The combination of mechanical removal and irrigation in most cases leads to a sufficient reduction in microbial load. Several studies have concluded that none of the currently used root canal treatment methods and endodontic instruments can completely clean root canals, especially root canals with "irregular anatomy". When preparing the upper molars with rotary instruments, 43% ± 29% and 33% ± 19% of the walls of the mesiobuccal and distobuccal channels, respectively, remained intact.&#x0D; Methodology. The article presents a case of treatment of a patient with a periapical abscess with a fistula communicating with the maxillary sinus, as well as concomitant maxillary sinusitis. Positive dynamics in the healing of the periradicular process was achieved by increasing the apical diameter of the preparation.&#x0D; Result. Healing of the periradicular process, as well as inflammatory phenomena in the maxillary sinus at the time of examination after 10 months from the start of treatment.&#x0D; Conclusions. Thus, an increase in the apical diameter to sizes "unusual" for a dentist (45.02, 50.02 according to ISO) not only contributes to the healing of the periradicular process, but also does not weaken the root of the tooth, since the true diameter of the apical zone is much larger than it seems at first glance.

Morphometric Predictors of Aortic Remodeling after Frozen Elephant Trunk Repair of Type A Dissection

We analyzed the predictors of postoperative aortic remodeling after the frozen elephant trunk technique for type A dissection. This retrospective study cohort comprised 20 patients who underwent the frozen elephant trunk technique for type A dissection. The incidence of aortic remodeling was evaluated at 4 levels: middle of the frozen elephant trunk, distal end of the frozen elephant trunk, 10th thoracic vertebra, and proximal to the celiac artery. Several parameters of the residual dissected aorta were analyzed at these 4 levels, and the predictors of aortic remodeling were investigated. The incidence of aortic remodeling was 85% at the middle of the frozen elephant trunk, 70% at the distal end of the frozen elephant trunk, 50% at the 10th thoracic vertebra, and 35% proximal to the celiac artery. In a total of 80 computed tomography images, there were significant differences between the aortic remodeling and nonremodeling groups in the true lumen diameter, false lumen diameter, true lumen/aortic diameter ratio, true lumen area, true lumen/aortic area ratio, and 2 parameters explaining the shape of the true lumen (created using elliptic Fourier analysis). Multivariate analysis revealed that the independent predictors of aortic remodeling were the true lumen/aortic area ratio and principal component 1. There were high incidences of aortic remodeling at the middle and distal end of the frozen elephant trunk. Multivariate analysis showed that the true lumen/aorta area ratio and the shape of the true lumen may be important predictors of aortic remodeling.

Aortic remodeling after false lumen occlusion using an atrial septal occluder in chronic DeBakey IIIb aortic dissection

ObjectiveRetrograde false lumen flow through distal entry tears poses a challenge in the treatment of chronic DeBakey IIIb aneurysms. In the present report, we have described the feasibility and outcomes of false lumen occlusion using an atrial septal occluder (ASO) in chronic DeBakey IIIb dissection associated with a descending aneurysm. MethodsAll the patients who had undergone thoracic endovascular aortic repair for chronic DeBakey IIIb aortic dissection at our institution from January 2014 to November 2020 were retrospectively reviewed. The primary endpoints were technical success and in-hospital postoperative results. The secondary endpoints included the midterm survival status and aortic remodeling outcomes. ResultsA total of 37 patients (age, 56.24 ± 10.47 years) with persistent retrograde false lumen perfusion and aneurysm formation at the thoracic segment were treated using an ASO for false lumen occlusion. We achieved 100% technical success. No spinal cord ischemia or in-hospital death was observed. The median follow-up time was 36 months (interquartile range, 24-51 months). After the procedure, three patients (8.1%) had had an endoleak (type Ia in two patients and type II in one patients), and five patients had required late reintervention. The overall 5-year survival rate was 71%. One aortic-related death (2.7% of the total cohort) occurred during follow-up at 9 months. Complete thrombosis of the false lumen along the treated aortic segment was recorded postoperatively in 34 patients (91.9%) at the final follow-up using computed tomography angiography. In a mixed-effects model, a diameter analysis revealed that the thoracic true lumen diameter had increased and the thoracic false lumen diameter had decreased significantly (0.256 mm/mo, P < .001; and −0.512 mm/mo, P < .001, respectively). ConclusionsThe combination of standard thoracic endovascular aortic repair and false lumen occlusion using the ASO to promote false lumen thrombosis and remodeling in the treated segments is a technically feasible and effective alternative treatment of chronic DeBakey IIIb dissection with an associated descending aneurysm. This approach yielded satisfactory midterm survival outcomes and a low incidence of aortic-related death in our patients. However, further studies with more subjects and a prospective design should verify our findings before routine clinical implementation of this technique.

Extensive Arch Repair with a Novel Two-Branched Stent Graft in Acute Type A Aortic Dissection.

Purpose: In this study, we compared the early results between the extensive arch repair with a novel two-branched stent graft (TSG) and the traditional technique.Methods: Between 2013 July and 2015 March, 63 acute type A aortic dissection (ATAAD) patients from four cardiac centers with indications for extensive arch repair were included in this study. Finally, 28 patients were involved in the traditional procedure (TP) group (23 males with the age of 49.75 ± 9.26 years) and 35 patients were involved in the TSG group (29 males with the age of 53.82 ± 8.17 years).Results: The operation was successful in all patients. The selective cerebral perfusion time, total operation time, and chest drainage within 24 hours after the operation in the TSG group were significantly less than those in the TP group (P ≤0.05). The mean follow-up time was 11.17 ± 1.74 months in the TP group and 11.94 ± 4.29 months in the TSG group. No statistical differences were found in aortic diameter, false lumen diameter, and true lumen diameter at the diaphragmatic level during the follow-up.Conclusion: Our technique with a novel TSG simplified the extensive arch repair procedure and was an effective way for the treatment of ATAAD.

Axon diameter inferences in the human corpus callosum using oscillating gradient spin echo sequences

Previous methods used to infer axon diameter distributions using magnetic resonance imaging (MRI) primarily use single diffusion encoding sequences such as pulsed gradient spin echo (PGSE) and are thus sensitive to axons of diameters >5 μm. We applied oscillating gradient spin echo (OGSE) sequences to study human axons in the 1–2 μm range in the corpus callosum, which include the majority of axons constituting cortical connections. The ActiveAx model was applied to calculate the fitted mean effective diameter for axons (AxD) and was compared with values found using histology. Axon diameters from histological data were calculated using three different datasets; true diameters (minimum diameter), a combination of minimum and maximum diameters, and diameters measured across a consistent diffusion direction. The AxD estimates from MRI were 1.8 ± 0.1 μm to 2.34 ± 0.04 μm with an average of 2.0 ± 0.2 μm for the ActiveAx model. The histology AxD values were 1.43 ± 0.02 μm when using the true minimum axon diameters, 5.52 ± 0.02 μm when using the combination of minimum and maximum axon diameters, and 2.20 ± 0.02 μm when collecting measurements across a consistent diffusion direction. This experiment demonstrates the first known usage of OGSE to calculate axon diameters in the human corpus callosum on a 1–2 μm scale. The importance for the model to account for axonal orientation dispersion is indicated by histological results which more closely match the MRI model results depending on the direction of axon diameter measurements. These initial steps using this non-invasive imaging method can be applied to future methodology to develop in vivo axon diameter measurements in human brain tissue.

Laparoscopic Trocar Dimensions: Marketed Versus True Dimensions – a Descriptive Study

<h3>Study Objective</h3> To establish true dimensions of single-use laparoscopic trocars as compared to marketed dimensions, calculate the corresponding incision sizes, and outline accessibility of information regarding true dimensions. <h3>Design</h3> Descriptive study <h3>Setting</h3> Laparoscopic disposable trocars available in North America are marketed in several distinct size categories. In practice, trocars in the same size category exhibit different functionality (ability to introduce instruments/needles and retrieve specimens) and warrant different incision sizes. <h3>Patients or Participants</h3> N/A. <h3>Interventions</h3> N/A. <h3>Measurements and Main Results</h3> True dimensions for 74 different trocars (bladeless, optical, and balloon) were obtained from 8 vendors covering 8 marketed size categories (3, 3.5, 5, 8, 10, 11, 12 and 15mm trocars). Mean difference across all trocars between marketed size and true inner diameter was 0.95 mm (standard deviation [SD] 0.47 mm, range 0-2.4 mm), with the widest range in the 5 mm category. For 5 mm ports, mean true inner diameter was 6.2 mm (SD 0.56, range 5.5 – 7.4) and true outer diameter 8.5 mm (SD 0.73, range 7.7-10.7). For 12 mm ports, mean true inner diameter was 13.0 mm (SD 0.27, range 12-13.3) and outer diameter 15.2 mm (SD 0.54, range 14.4-16.8). Corresponding incision sizes were calculated as half the circumference (π*outer diameter/2). Five mm ports necessitate a mean incision size of 13.3 mm (SD 1.15, range 12.1-16.8) and 12 mm ports a mean incision of 23.9 mm (SD 0.85, range 22.6-26.4). One out of 8 vendors stated actual inner diameters on their company website and/or catalogue, no vendors stated actual outer diameters. <h3>Conclusion</h3> Trocars in the same size category give a false sense of standardization with considerable differences in both inner and outer diameters, corresponding to differences in functionality and incision sizes. Accessibility to information on true dimensions is limited. Future directions include assessment of the incisional site hernia literature for consideration of true trocar dimensions and surgeons' perceptions of trocar dimensions.

En Bloc Arch Reconstruction With the Frozen Elephant Trunk Technique for Acute Type a Aortic Dissection.

Objective: The study objective was to evaluate the effect of en bloc arch reconstruction with frozen elephant trunk (FET) technique for acute type A aortic dissection.Methods: 41 patients with acute Stanford type A dissection underwent en bloc arch reconstruction combined with FET implantation between April 2018 and August 2020. The mean age of the patients was 46 ± 13 years, and 9 patients were female. One patient had Marfan syndrome. Six patients had pericardial tamponade, 9 had pleural effusion, 5 had transient cerebral ischemic attack, and 3 had chronic kidney disease.Results: The hospital mortality rate was 9.8% (4 patients). 2 (4.9%) patients had stroke, 23 (56.1%) had acute kidney injury, and 5 (12.2%) had renal failure requiring hemodialysis. During follow-up, the rate of complete false lumen thrombosis was 91.6% (33/36) around the FET, 69.4% (25/36) at the diaphragmatic level, and 27.8% (10/36) at the superior mesenteric artery level. The true lumen diameter at the same three levels of the descending aorta increased significantly while the false lumen diameter reduced at the two levels: pulmonary bifurcation and the diaphragm. The 1-, 2-and 3-year actuarial survival rates were 90.2% [95% confidence interval (CI), 81.2–99.2], 84.2% (95% CI, 70.1–98.3) and 70.2% (95% CI, 42.2–98), respectively.Conclusions: In patients with acute type A dissection, en bloc arch reconstruction with FET technique appeared to be feasible and effective with early clinical follow-up results. Future studies including a large sample size and long-term follow-up are required to evaluate the efficacy.

Instance segmentation of root crops and simulation-based learning to estimate their physical dimensions for on-line machine vision yield monitoring

Modern agriculture is based on control and optimization, where monitoring is essential. But yield monitoring limited to spatial mapping of biomass is unsatisfactory for uniformity optimization. Acquiring this information as soon as during the harvest could improve efficiency of precision agriculture. Current machine vision solutions do not allow this for several reasons, starting with difficulties with recognition of heavily cluttered, often mutually occluding objects, or requirements for elaborate hardware. Acquiring images in on-line conditions often results in perspective distortion which makes measurement difficult. This is even more challenging in the case of root crops, as they are usually graded basing on their minimal diameter, which is not directly observable via monocular vision.We propose a method for developing yield monitoring systems that can estimate physical dimensions of crops directly on-line. In our approach, individual plants are segmented using Mask R-CNN, allowing clear separation even in heavily cluttered conditions and in the presence of occlusions. Then, a nonlinear regression model is used to predict the minimal diameter of each plant basing on their observed contours. This model is capable of jointly correcting the perspective distortion and estimate the non-observed dimension. Training this model requires per-object annotations with their true diameters. Since this information is very difficult to acquire for real crops, we build a simulation environment where we model the crops, eventually rendering a synthetic dataset to train the regression model on. The size estimation model transfers the knowledge from simulated data, correctly predicting the sizes of real plants. We demonstrate our method on the case of potatoes, but it can be applied to other crops as well.

Impact of thoracic endovascular aortic repair timing on aortic remodeling in acute type B aortic intramural hematoma

ObjectiveThoracic endovascular aortic repair (TEVAR) is increasingly utilized in the management of acute type B aortic intramural hematoma (TBIMH). Optimal timing for intervention has not been described. The aim of this study was to evaluate TEVAR timing on postoperative aortic remodeling. MethodsA retrospective chart review was performed on patients who underwent TEVAR for TBIMH from January 2008 to September 2018. Imaging was reviewed pre- and postoperatively. Primary data points included true lumen diameter (TLD) and total aortic diameter (TAD) at the site of maximal pathology. Primary endpoint was aortic remodeling evidenced by a TAD/TLD ratio closest to 1.0. Secondary outcome was occurrence of aortic-related adverse events and mortality (AREM): aortic rupture, aortic-related death, progression to dissection, or need for aortic reintervention within 12 months. Patients undergoing emergent TEVAR (within 24 hours, ‘eTEVAR’) were compared with the remainder – delayed TEVAR (‘dTEVAR’). ResultsWe analyzed 71 patients that underwent TEVAR for TBIMH; 25 underwent emergent TEVAR and 46 patients underwent dTEVAR (median, 5.5 days; range, 2-120 days). There were no differences in demographics and comorbidities, and patients did not differ in presenting IMH thickness (12.6 ± 3.1 vs 11.3 ± 4.1 mm; P = .186) nor presenting TAD/TLD ratio (1.535 ± 0.471 vs 1.525 ± 0.397; P = .928) for eTEVAR and dTEVAR groups, respectively. eTEVAR patients had larger average presenting maximal descending aortic diameter (45.8 ± 14.3 vs 38.2 ± 7.5 mm; P = .018) and higher incidence of penetrating aortic ulcer on presenting computed tomography angiography (52.0% vs 21.7%; P = .033). Thirty-day mortality was 2 of 25 (8.0%) for eTEVAR and 2 of 45 (4.4%) for dTEVAR (P = .602). Postoperative aortic remodeling was more complete in the dTEVAR group (1.23 ± 0.12 vs 1.33 ± 0.15; P = .004). Case-control matching (controlling for presenting descending aortic diameter and penetrating aortic ulcer) on 30 patients still showed better aortic remodeling in the dTEVAR group (1.125 ± 0.100 vs 1.348 ± 0.42; P < .001). The incidence of AREM was higher in the eTEVAR (6/25; 24.0%) group compared with the dTEVAR group (2/46; 4.3%). At 12 months, freedom from AREM was higher in the dTEVAR group (95.7% vs 76.0%; P = .011). Postoperative TAD/TLD ratio was the best predictor for late aortic-related adverse events (area under the receiver operator characteristic = 0.825; P = .003). ConclusionsTEVAR for acute TBIMH within 24 hours of admission is associated with lower aortic remodeling and higher occurrence of late AREM. Delaying TEVAR when clinically possible could improve aortic remodeling and aortic-related outcomes.

Aortic remodelling and false lumen changes after the frozen elephant trunk technique using the thoraflex hybrid stented graft for aortic dissection

BackgroundDespite the marked improvement in the aortic dissection repair techniques, residual dissected aorta with a patent false lumen remains an issue. So, the aim of our study is to observe the effect of inserting the Thoraflex Hybrid Graft on the aortic diameters in patients with type A aortic dissection involving the arch and descending aorta. Patients with type I aortic dissection who had aortic dissection repair using the Thoraflex Hybrid Graft in University Hospitals Birmingham were studied. Radiological assessment with computed tomography of the aorta was done at the level of the diaphragm to measure the true lumen, false lumen and total aortic diameters. Significance of change of diameters at early post-operative as compared to the pre-operative period was analysed.ResultsEight cases were done in the acute setting, while 14 cases were done in the chronic setting. The ratio of true lumen to the total aortic diameter has significantly increased in the follow-up period as compared to the pre-operative period (P = 0.031). Whereas false lumen to total aortic diameter ratio has significantly decreased (P = 0.024). Subgroup analysis revealed that these changes were not significantly altered by whether the dissection was acute or chronic.ConclusionsThe Thoraflex Hybrid Graft will induce positive aortic remodelling with expansion of true lumen and will diminish the false lumen. But we could not find a significant difference between acute or chronic cases due to small sample size.