Fractal dimension in CT low attenuation areas is predictive of long-term oxygen therapy initiation in COPD patients: Results from two observational cohort studies

BackgroundSome chronic obstructive pulmonary disease (COPD) patients develop hypoxemia with disease progression, with some even requiring long-term oxygen therapy (LTOT). Lung function, especially diffusing capacity, and the annual decline in PaO₂, are reported to be predictive factors of chronic respiratory failure. However, the association between lung morphometry evaluated using computed tomography (CT) images and LTOT initiation is unknown.MethodsWe retrospectively evaluated the relationship between clinical indices, including pulmonary function, body mass index (BMI), and CT parameters, at baseline and LTOT initiation in two prospective COPD cohorts. In the Nara Medical University cohort (n = 76), the low attenuation area (LAA) and its fractal dimension (fractal D) were adapted as the indices for parenchymal destruction in CT images. The association between these CT measurements and LTOT initiation was replicated in the Kyoto University cohort (n = 130).ResultsIn the Nara Medical University cohort, lower BMI (hazard ratio [HR]:0.70, p = 0.006), lower % diffusing capacity (%DLCO) (HR: 0.92, p = 0.006), lower %DLCO/VA (HR, 0.90, p = 0.008), higher RV/TLC (HR, 1.26, p = 0.012), higher LAA% (HR: 1.18, p = 0.001), and lower fractal D (HR: 3.27 × 10^?8, p < 0.001) were associated with LTOT initiation. Multivariate analysis in the Kyoto University cohort confirmed that lower %DLCO and lower fractal D were independently associated with LTOT initiation, whereas LAA% was not.ConclusionFractal D, which is the index for morphometric complexity of LAA in CT analysis, is predictive of LTOT initiation in COPD patients.     

Differentiating autoimmune pancreatitis from pancreatic ductal adenocarcinoma with CT radiomics features

PurposeThe purpose of this study was to determine whether computed tomography (CT)-based machine learning of radiomics features could help distinguish autoimmune pancreatitis (AIP) from pancreatic ductal adenocarcinoma (PDAC).Materials and MethodsEighty-nine patients with AIP (65 men, 24 women; mean age, 59.7 ± 13.9 [SD] years; range: 21–83 years) and 93 patients with PDAC (68 men, 25 women; mean age, 60.1 ± 12.3 [SD] years; range: 36–86 years) were retrospectively included. All patients had dedicated dual-phase pancreatic protocol CT between 2004 and 2018. Thin-slice images (0.75/0.5 mm thickness/increment) were compared with thick-slices images (3 or 5 mm thickness/increment). Pancreatic regions involved by PDAC or AIP (areas of enlargement, altered enhancement, effacement of pancreatic duct) as well as uninvolved parenchyma were segmented as three-dimensional volumes. Four hundred and thirty-one radiomics features were extracted and a random forest was used to distinguish AIP from PDAC. CT data of 60 AIP and 60 PDAC patients were used for training and those of 29 AIP and 33 PDAC independent patients were used for testing.ResultsThe pancreas was diffusely involved in 37 (37/89; 41.6%) patients with AIP and not diffusely in 52 (52/89; 58.4%) patients. Using machine learning, 95.2% (59/62; 95% confidence interval [CI]: 89.8–100%), 83.9% (52:67; 95% CI: 74.7–93.0%) and 77.4% (48/62; 95% CI: 67.0–87.8%) of the 62 test patients were correctly classified as either having PDAC or AIP with thin-slice venous phase, thin-slice arterial phase, and thick-slice venous phase CT, respectively. Three of the 29 patients with AIP (3/29; 10.3%) were incorrectly classified as having PDAC but all 33 patients with PDAC (33/33; 100%) were correctly classified with thin-slice venous phase with 89.7% sensitivity (26/29; 95% CI: 78.6–100%) and 100% specificity (33/33; 95% CI: 93–100%) for the diagnosis of AIP, 95.2% accuracy (59/62; 95% CI: 89.8–100%) and area under the curve of 0.975 (95% CI: 0.936–1.0).ConclusionsRadiomic features help differentiate AIP from PDAC with an overall accuracy of 95.2%.     

Perfusion pressure flow study in the upper urinary tract

Hydronephrosis with an undetermined pathology is a common condition detected in imaging studies. In urological clinical practice, it is a persistent dilemma to predict whether this condition will progress to result in the deterioration of renal function. Perfusion pressure flow study of the upper urinary tract, known as the Whitaker test, provides an alternative diagnostic tool for solving this condition. Perfusion pressure flow study has been criticized for its invasiveness, nonphysiological approach, and inconsistency in predicting outcomes. However, it continues to be used to evaluate difficult or equivocal cases and to provide an objective assessment of the upper urinary tract.     

胸腔镜下心包厚壁囊肿切除术1例报告

面对来势汹汹的新型冠状病毒肺炎(COVID-19),如何能够正确、快速诊断和筛检出确诊病例显得尤为重要,国内诸多科技工作者都在积极开展相关的诊断试验研究。本文回顾了目前正在开展的十余项诊断试验的注册信息,针对其中存在的共性问题进行了讨论,重点阐述了如何使用PICOS原则构造COVID-19诊断试验的研究问题,还对金标准的设置、受试者的代表性、样本量计算和同步、独立、盲法的测定等诊断试验的设计要点进行了详细说明。旨在为广大研究者提供开展COVID-19诊断试验的设计建议,帮助研究者在顶层设计阶段减少、避免偏倚,完成高质量的临床研究,为临床诊疗提供循证医学证据。     

A modality-specific somatosensory evoked potential test protocol for clinical evaluation: A feasibility study

ObjectiveWe aimed to establish an objective neurophysiological test protocol that can be used to assess the somatosensory nervous system.MethodsIn order to assess most fiber subtypes of the somatosensory nervous system, repetitive stimuli of seven different modalities (touch, vibration, pinprick, cold, contact heat, laser, and warmth) were synchronized with the electroencephalogram (EEG) and applied on the cheek and dorsum of the hand and dorsum of the foot in 21 healthy subjects and three polyneuropathy (PNP) patients. Latencies and amplitudes of the modalities were assessed and compared. Patients received quantitative sensory testing (QST) as reference.ResultsWe found reproducible evoked potentials recordings for touch, vibration, pinprick, contact-heat, and laser stimuli. The recording of warm-evoked potentials was challenging in young healthy subjects and not applicable in patients. Latencies were shortest within Aβ-fiber-mediated signals and longest within C-fibers. The test protocol detected function loss within the Aβ-fiber and Aδ-fiber-range in PNP patients. This function loss corresponded with QST findings.ConclusionIn this pilot study, we developed a neurophysiological test protocol that can specifically assess most of the somatosensory modalities. Despite technical challenges, initial patient data appear promising regarding a possible future clinical application.SignificanceEstablished and custom-made stimulators were combined to assess different fiber subtypes of the somatosensory nervous system using modality-specific evoked potentials.     

P-Values and Power in Orthopedic Research: Myths and Reality

The results of statistical tests in orthopedic studies are typically reported using P-values. If a P-value is smaller than the pre-determined level of significance (eg, < .05), the null hypothesis is rejected in support of the alternative. This automaticity in interpreting statistical results without consideration of the power of the study has been denounced over the years by statisticians, since it can potentially lead to misinterpretation of the study conclusions. In this paper, we review fundamental misconceptions and misinterpretations of P-values and power, along with their connection with confidence intervals, and we provide guidelines to orthopedic researchers for evaluating and reporting study results. We provide real-world orthopedic examples to illustrate the main concepts. Please visit the following https://youtu.be/bdPU4luYmF0 for videos that explain the highlights of the paper in practical terms.     

Family-centered Care for Sick Newborns: A Thumbnail View

Family-centered care (FCC) for sick newborns is emerging as a paradigmatic shift in the practice of facility-based newborn care. It seeks to transforming a provider-centered model into a client-centered one and thus build a new therapeutic alliance. FCC is the cornerstone of continuum of care, imparting caregiving competencies to parents/caregivers both within institutions as well as after the discharge. This has potential gains for the newborn, family members, and facility-level staff. The initial model piloted in tertiary-care settings is now undergoing translation at five sites across the country; the outcomes are keenly awaited.     

High-intensity interval exercise lowers postprandial glucose concentrations more in obese adults than lean adults

AimsTo compare postprandial glucose responses to high-intensity interval exercise (HIE) between obese and lean individuals.MethodsThirty healthy young adult males (15 obese, 15 lean) ate a standardised meal, then performed HIE (4 × 30-s Wingate cycling/4-min rest) or a no-exercise control trial (CON). Blood glucose was measured preprandially and up to 150 min postprandially.ResultsCompared to CON, HIE reduced postprandial glucose concentrations at 120–150 min in obese (p < 0.001) and lean men (p < 0.05), with greater reductions in obese than lean subjects at 120 (−27.0% vs. −8.3%), 135 (−31.9% vs. −15.7%), and 150 min (−21.8% vs. −10.6%). The total glucose area under the curve (AUC) for the testing period was lower with HIE than CON among obese men (p < 0.05), but not lean men (p > 0.05). We found moderate correlations between body mass and postprandial glucose changes (r = 0.39–0.44, p < 0.05), and between glucose AUC and body mass and fat free mass (r = 0.39–0.48, p < 0.05).ConclusionsOur findings suggest that HIE may act as a time-efficient lifestyle intervention strategy for improving obesity-related diabetes risk factors, and might play a role in primary diabetes prevention for the healthy but sedentary population.