Data augmentation for medical image segmentation

医用画像のセマンティックセグメンテーションは、人手を介さずにピクセルとラベルを関連付けることを目的としている。深層学習を用いるには、大量の教師画像データが不可欠であるが、多くの場合で利用できない。本研究では、様々なフィルタを用いた効率的なデータの水増し法を検討した。実験結果は、ガウシアンフィルタとメディアンフィルタの組み合わせが、骨画像のセマンティックセグメンテーションに適していることを示した。Semantic segmentation of medical images aims to associate a pixel with a label in a medical image without human interaction. The success of semantic segmentation using deep learning techniques is contingent on the availability of a large amount of imaging data with corresponding labels provided by experts. In contrast, a large amount of labeled medical image data is not available in many cases. In this study, we investigate an efficient data augmentation method using various filters. The experimental results showed that the combination between Gaussian and Median filters is adequate for semantic segmentation for bone images.application/pdfdepartmental bulletin pape

Measurement of Time-Dependent CP-Violating Asymmetries in B0→ϕKS0, K+K-KS0, and η′KS0 Decays

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The Strong Transfer Paradox in an Overlapping Generations Framework

2005-07It is shown that in an overlapping generations model, a strong transfer paradox occurs through permanent transfer in a dynamically efficient region because of international capital mobility. A graphical explanation is also provided to show how the strong paradox arises.departmental bulletin pape

Electrospun MEH-PPV/SBA-15 Composite Nanofibers Using a Dual Syringe Method

The process of electrospinning, which produces fibers in the nanometer to micron range under the influence of high voltages, has been widely studied to produce polymer and textile fibers. Mesoporous molecular sieve fibers have been produced in our lab, and this technique was extended to produce an interwoven mesh of polymer−molecular sieve composite fibers. The electroluminescent polymer MEH-PPV and molecular sieve SBA-15 were used to produce the composite fibers. An interesting aspect of these composites is that the fluorescence of MEH-PPV is blue shifted in the composites. The composites have been characterized by microscopy, vibrational spectroscopy, and fluorescence measurements

Table_1_Association of Carotid Plaque Morphology and Glycemic and Lipid Parameters in the Northern Manhattan Study.DOCX

Low Gray-Scale Median (GSM) index is an ultrasonographic parameter of soft, lipid rich plaque morphology that has been associated with stroke and cardiovascular disease (CVD). We sought to explore the contribution of the modifiable and not-modifiable cardiovascular risk factors (RFs) to vulnerable plaque morphology measured by the low GSM index. A total of 1,030 stroke-free community dwelling individuals with carotid plaques present (mean age, 71.8 ± 9.1; 58% women; 56% Hispanic, 20% Non-Hispanic Black, 22% Non-Hispanic White) were assessed for minimum GSM (min GSM) using high-resolution B-mode carotid ultrasound. Multiple linear regression models were used to evaluate the association between RFs and minGSM after adjusting for sociodemographic characteristics. Within an individual, median plaque number was 2 (IQR: 1–3) and mean plaque number 2.3 (SD: 1.4). Mean minGSM was 78.4 ± 28.7 (IQR: 56–96), 76.3 ± 28.8 in men and 80 ± 28.5 in women; 78.7 ± 29.3 in Hispanics participants, 78.5 ± 27.2 in Non-Hispanic Black participants, and 78.2 ± 29 in Non-Hispanic white participants. In multivariable adjusted model, male sex (β = −5.78, p = 0.007), obesity BMI (β = −6.92, p = 0.01), and greater levels of fasting glucose (β = −8.02, p = 0.02) and LDL dyslipidemia (β = −6.64, p = 0.005) were positively associated with lower minGSM, while presence of glucose lowering medication resulted in a significant inverse association (β = 7.68, p = 0.04). Interaction (with p for interaction <0.1) and stratification analyses showed that effect of age on minGSM was stronger in men (β = −0.44, p = 0.03) than in women (β = −0.20, p = 0.18), and in individuals not taking glucose lowering medication (β = −0.33, p = 0.009). Our study has demonstrated an important contribution of glycemic and lipid metabolism to vulnerable, low density or echolucent plaque morphology, especially among men and suggested that use of glucose lowering medication was associated with more fibrose-stable plaque phenotype (greater GSM). Further research is needed to evaluate effects of medical therapies in individuals with vulnerable, low density, non-stenotic carotid plaques and how these effects translate to prevention of cerebrovascular disease.</p

Association between P-wave terminal force in lead V₁ (PTFV₁) and risk of Subclinical Cerebral Infarcts (n = 1174).

Association between P-wave terminal force in lead V1 (PTFV1) and risk of Subclinical Cerebral Infarcts (n = 1174).</p

Association of P-wave terminal force in lead V₁ (PTFV₁) with white matter hyperintensity volume (n = 1172).

Association of P-wave terminal force in lead V1 (PTFV1) with white matter hyperintensity volume (n = 1172).</p

Baseline characteristics of the Northern Manhattan Study Magnetic Resonance Imaging cohort (n = 1174).

Baseline characteristics of the Northern Manhattan Study Magnetic Resonance Imaging cohort (n = 1174).</p

Table_1_Subclinical Magnetic Resonance Imaging Markers of Cerebral Small Vessel Disease in Relation to Office and Ambulatory Blood Pressure Measurements.doc

BackgroundTwenty-four-hour and nighttime blood pressure (BP) levels are more strongly associated with cardiovascular risk than office or daytime BP measurements. However, it remains undocumented which of the office and ambulatory BP measurements have the strongest association and predictive information in relation to the presence of type I, or arteriolosclerosis type, cerebral small vessel diseases (CSVD).MethodsA subset of 429 participants from the Maracaibo Aging Study [aged ≥40 years (women, 73.7%; mean age, 59.3 years)] underwent baseline brain magnetic resonance imaging (MRI) to visualize CSVD, which included log-transformed white matter hyperintensities (log-WMH) volume and the presence (yes/no) of lacunes, cerebral microbleeds (CMB), or enlarged perivascular spaces (EPVS). Linear and logistic regression models were applied to examine the association between CSVD and each +10-mmHg increment in the office and ambulatory systolic BP measurements. Improvement in the fit of nested logistic models was assessed by the log-likelihood ratio and the generalized R2 statistic.ResultsOffice and ambulatory systolic BP measurements were related to log-WMH (β-correlation coefficients ≥0.08; P 2 ≤ 3.82%). Compared to 24-h and daytime systolic BP, nighttime systolic BP had the strongest improvement in the model performance; for WMH (1.46 vs. 1.05%) and lacunes (3.06 vs. ≤ 2.05%).ConclusionsTwenty-four-hour and nighttime systolic BP were the more robust BP measurements associated with CSVD, but the nighttime systolic BP level had the strongest association. Controlling ambulatory BP levels might provide additional improvement in the prevention of CSVD.</p

Supplemental Material - Association of brain arterial diameters with demographic and anatomical factors in a multi-national pooled analysis of cohort studies

Supplemental Material for Association of brain arterial diameters with demographic and anatomical factors in a multi-national pooled analysis of cohort studies by Victor J Del Brutto, Farid Khasiyev, Minghua Liu, Antonio Spagnolo-Allende, Ye Qiao, Jesus D Melgarejo Arias, Vanessa A Guzman, Kay C Igwe, Danurys Sanchez, Howard Andrews, Clarissa D Morales, Meagan T Farrell, Darina T Bassil, Sudha Seshadri, Ryan G Wagner, Victor Mngomezulu, Jennifer Manly, Mitchell SV Elkind, Lisa Berkman, Jose R Romero, Gladys E Maestre, Oscar H Del Brutto, Adam M Brickman, Narayanaswamy Venketasubramanian, Christopher Chen, Caroline Robert, Saima Hilal, Tatjana Rundek, Bruce A Wasserman and Jose Gutierrez in The Neuroradiology Journal</p