Two spherical bubbles with changing radii are considered to be moving in ideal fluid along their center-line. The exact expression for the fluid kinetic energy is obtained. The Stokes stream function ...is expanded in Gegenbauer polynomials in bispherical coordinates. This expansion is used to obtain the exact series for the fluid kinetic energy quadratic form coefficients. The new series are confirmed to be correct by comparison with the known ones. The main advantage of the new kinetic energy form is the possibility to obtain asymptotic expansions at small separation distance between the bubbles. These expansions are obtained and their convergence is analyzed. The results of this work can be used to describe the bubbles approach before the contact and their coalescence in acoustic field.
Interval colorectal cancers (interval CRCs), that is, cancers occurring after a negative screening test or examination, are an important indicator of the quality and effectiveness of CRC screening ...and surveillance. In order to compare incidence rates of interval CRCs across screening programmes, a standardised definition is required. Our goal was to develop an internationally applicable definition and taxonomy for reporting on interval CRCs.
Using a modified Delphi process to achieve consensus, the Expert Working Group on interval CRC of the Colorectal Cancer Screening Committee of the World Endoscopy Organization developed a nomenclature for defining and characterising interval CRCs.
We define an interval CRC as a "colorectal cancer diagnosed after a screening or surveillance exam in which no cancer is detected, and before the date of the next recommended exam". Guidelines and principles for describing and reporting on interval CRCs are provided, and clinical scenarios to demonstrate the practical application of the nomenclature are presented.
The Working Group on interval CRC of the World Endoscopy Organization endorses adoption of this standardised nomenclature. A standardised nomenclature will facilitate benchmarking and comparison of interval CRC rates across programmes and regions.
We consider the interaction between two spherical bubbles of variable radii during their movement along their centerline in a viscous fluid. The Stokes stream function is found in bispherical ...coordinates as an expansion in Gegenbauer polynomials. Viscous forces that act on the sphere are represented as infinite series. Their asymptotics near the contact point is found.
Serrated polyposis syndrome (SPS) is accompanied by an increased risk of colorectal cancer (CRC). Patients fulfilling the clinical criteria, as defined by the WHO, have a wide variation in CRC risk. ...We aimed to assess risk factors for CRC in a large cohort of patients with SPS and to evaluate the risk of CRC during surveillance.
In this retrospective cohort analysis, all patients with SPS from seven centres in the Netherlands and two in the UK were enrolled. WHO criteria were used to diagnose SPS. Patients who only fulfilled WHO criterion-2, with IBD and/or a known hereditary CRC syndrome were excluded.
In total, 434 patients with SPS were included for analysis; 127 (29.3%) were diagnosed with CRC. In a per-patient analysis ≥1 serrated polyp (SP) with dysplasia (OR 2.07; 95% CI 1.28 to 3.33), ≥1 advanced adenoma (OR 2.30; 95% CI 1.47 to 3.67) and the fulfilment of both WHO criteria 1 and 3 (OR 1.60; 95% CI 1.04 to 2.51) were associated with CRC, while a history of smoking was inversely associated with CRC (OR 0.36; 95% CI 0.23 to 0.56). Overall, 260 patients underwent surveillance after clearing of all relevant lesions, during which two patients were diagnosed with CRC, corresponding to 1.9 events/1000 person-years surveillance (95% CI 0.3 to 6.4).
The presence of SPs containing dysplasia, advanced adenomas and/or combined WHO criteria 1 and 3 phenotype is associated with CRC in patients with SPS. Patients with a history of smoking show a lower risk of CRC, possibly due to a different pathogenesis of disease. The risk of developing CRC during surveillance is lower than previously reported in literature, which may reflect a more mature multicentre cohort with less selection bias.
The conditions for the coalescence of two pulsating spherical bubbles in a liquid in a weak low-frequency acoustic pressure field, as well as the conditions for absence of such a fusion, have been ...studied. Since the frequency of the pressure field is much lower than natural frequencies, the bubbles pulsate with identical relative amplitudes and phases. At large distances, bubbles approach according to the Bjerknes law. However, viscous forces near a contact can compensate the attraction force and bubbles do not coalesce. It has been shown that bubbles coalesce when the ratio of radii is smaller than 3; otherwise, periodic oscillations are established at a small gap between the surfaces of bubbles and coalescence does not occur. These theoretical results have been confirmed by existing experiments.
Quantitative image analysis models are used for medical imaging tasks such as registration, classification, object detection, and segmentation. For these models to be capable of making accurate ...predictions, they need valid and precise information. We propose PixelMiner, a convolution-based deep-learning model for interpolating computed tomography (CT) imaging slices.
PixelMiner was designed to produce texture-accurate slice interpolations by trading off pixel accuracy for texture accuracy. PixelMiner was trained on a dataset of 7829 CT scans and validated using an external dataset. We demonstrated the model's effectiveness by using the structural similarity index (SSIM), peak signal to noise ratio (PSNR), and the root mean squared error (RMSE) of extracted texture features. Additionally, we developed and used a new metric, the mean squared mapped feature error (MSMFE). The performance of PixelMiner was compared to four other interpolation methods: (tri-)linear, (tri-)cubic, windowed sinc (WS), and nearest neighbor (NN).
PixelMiner produced texture with a significantly lowest average texture error compared to all other methods with a normalized root mean squared error (NRMSE) of 0.11 (p < .01), and the significantly highest reproducibility with a concordance correlation coefficient (CCC) ≥ 0.85 (p < .01).
PixelMiner was not only shown to better preserve features but was also validated using an ablation study by removing auto-regression from the model and was shown to improve segmentations on interpolated slices.
•A novel architecture for performing interpolation of slices in CT.•A generative deep learning approach that uses an explicit density model.•Towards texture accurate slice interpolation.•Slice interpolation without common artifacts caused by traditional interpolation.•Towards improved slice interpolation for the purpose of improving downstream tasks suck as detection, classification, and segmentation.
The trinomial asymptotic expansions of potential flow kinetic energy in an ideal fluid are constructed for the motion of two spheres of variable radii in the vicinity of their contact. Based on these ...expansions, it is possible to study the process of two pulsating gas bubbles approaching up to their contact.
•LCNEC has radiological characteristics of both SCLC and NSCLC.•LCNEC can be classified in molecular SCLC-like and NSCLC-like subtypes.•Molecular LCNEC subtypes could not be identified based on ...radiological imaging.•Most LCNEC are molecular SCLC-like, but have a radiological NSCLC-like appearance.•These results highlight LCNEC as a unique tumor entity.
Radiological characteristics and radiomics signatures can aid in differentiation between small cell lung carcinoma (SCLC) and non-small cell lung carcinoma (NSCLC). We investigated whether molecular subtypes of large cell neuroendocrine carcinoma (LCNEC), i.e. SCLC-like (with pRb loss) vs. NSCLC-like (with pRb expression), can be distinguished by imaging based on (1) imaging interpretation, (2) semantic features, and/or (3) a radiomics signature, designed to differentiate between SCLC and NSCLC.
Pulmonary oncologists and chest radiologists assessed chest CT-scans of 44 LCNEC patients for ‘small cell-like’ or ‘non-small cell-like’ appearance. The radiologists also scored semantic features of 50 LCNEC scans. Finally, a radiomics signature was trained on a dataset containing 48 SCLC and 76 NSCLC scans and validated on an external set of 58 SCLC and 40 NSCLC scans. This signature was applied on scans of 28 SCLC-like and 8 NSCLC-like LCNEC patients.
Pulmonary oncologists and radiologists were unable to differentiate between molecular subtypes of LCNEC and no significant differences in semantic features were found. The area under the receiver operating characteristics curve of the radiomics signature in the validation set (SCLC vs. NSCLC) was 0.84 (95% confidence interval (CI) 0.77-0.92) and 0.58 (95% CI 0.29-0.86) in the LCNEC dataset (SCLC-like vs. NSCLC-like).
LCNEC appears to have radiological characteristics of both SCLC and NSCLC, irrespective of pRb loss, compatible with the SCLC-like subtype. Imaging interpretation, semantic features and our radiomics signature designed to differentiate between SCLC and NSCLC were unable to separate molecular LCNEC subtypes, which underscores that LCNEC is a unique disease.
Patients with Lynch syndrome may develop colorectal cancer (CRC), despite intensive colonoscopic surveillance. Nonpolypoid colorectal neoplasms might be a major contributor to the occurrence of these ...cancers. The aim of this case - control study was to compare the endoscopic appearance of colorectal neoplasms between patients with Lynch syndrome and control individuals at average risk for CRC.
The endoscopists at the Maastricht University Medical Center were first given training to ensure familiarity with the appearance and classification of nonpolypoid lesions. Patients with Lynch syndrome and patients at average risk for CRC who underwent elective colonoscopy at the Center were prospectively included. Nonpolypoid lesions were defined as lesions with a height of less than half the diameter, and advanced histology was defined as the presence of high grade dysplasia or early cancer.
A total of 59 patients with Lynch syndrome (mean age 48.7 years, 47.5 % men) and 590 matched controls (mean age 50.2 years, 47.5 % men) were included. In patients with Lynch syndrome, adenomas were significantly more likely to be nonpolypoid than they were in controls: 43.3 % vs. 16.9 % (OR 3.60, 95 %CI 1.90 - 6.83; P < 0.001). This was particularly true for proximal adenomas: 58.1 % vs. 16.3 % (OR 6.93, 95 %CI 2.92 - 16.40; P < 0.001). Adenomas containing advanced histology were more often nonpolypoid in patients with Lynch syndrome than in controls (4/5, 80.0 % vs. 5/17, 29.4 %; P = 0.19). Serrated polyps were also more often nonpolypoid in patients with Lynch syndrome than in controls: 49.2 % vs. 20.4 % (OR 3.57, 95 %CI 1.91 - 6.68; P < 0.001).
In patients with Lynch syndrome, colorectal neoplasms are more likely to have a nonpolypoid shape than those from average risk patients, especially in the proximal colon. These findings suggest that proficiency in recognition and endoscopic resection of nonpolypoid colorectal lesions are needed to ensure colonoscopic prevention against CRC in this high risk population.
Purpose
Despite colonoscopic surveillance, Lynch syndrome patients develop colorectal cancer (CRC). Identification of modifiable factors has the potential to improve outcome of surveillance. The aims ...of this study were to determine (1) characteristics of patients with CRC, (2) endoscopic and histological features of these cancers, and (3) quality of the previous colonoscopy.
Methods
Approximately 2,200 medical reports from proven and obligate mutation carriers identified at the Dutch Lynch Syndrome Registry and two large hospitals were retrospectively analyzed for the presence of an interval cancer defined as CRC diagnosed within 24 months of previous colonoscopy.
Results
Thirty-one interval cancers were detected in 29 patients (median age of 52 range 35–73), after a median time of 17 months. All were MLH1 or MSH2 mutation carriers, and 39 % had a previous CRC. In patients without previous surgery for CRC, 84 % was proximally located. Of all interval cancers, 77 % were at local stage (T1–3N0Mx). In three patients (9 %) with an incomplete previous colonoscopy, CRC was located in the unexamined colon. In six of the nine patients with an adenoma during previous colonoscopy, the cancer was detected in the same colonic segment as the previously removed adenoma.
Conclusions
Interval cancers were detected in MLH1 and MSH2 mutation carriers, especially in those with a history of previous CRC and between 40 and 60 years. Interval cancer could be related to incompleteness of previous endoscopy and possibly residual adenomatous tissue. Further reduction of the interval cancer risk may be achieved by optimizing endoscopy quality and individualization of surveillance guidelines.
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