Arterial spin labeling MR image denoising and reconstruction using unsupervised deep learning

Arterial spin labeling (ASL) imaging is a powerful magnetic resonance imaging technique that allows to quantitatively measure blood perfusion non-invasively, which has great potential for assessing tissue viability in various clinical settings. However, the clinical applications of ASL are currently limited by its low signal-to-noise ratio (SNR), limited spatial resolution, and long imaging time. In this work, we propose an unsupervised deep learning-based image denoising and reconstruction framework to improve the SNR and accelerate the imaging speed of high resolution ASL imaging. The unique feature of the proposed framework is that it does not require any prior training pairs but only the subject's own anatomical prior, such as T1-weighted images, as network input. The neural network was trained from scratch in the denoising or reconstruction process, with noisy images or sparely sampled k-space data as training labels. Performance of the proposed method was evaluated using in vivo experiment data obtained from 3 healthy subjects on a 3T MR scanner, using ASL images acquired with 44-min acquisition time as the ground truth. Both qualitative and quantitative analyses demonstrate the superior performance of the proposed txtc framework over the reference methods. In summary, our proposed unsupervised deep learning-based denoising and reconstruction framework can improve the image quality and accelerate the imaging speed of ASL imaging.     

Genome-wide gene and serum ferritin interaction in the development of type 2 diabetes in adults aged 40 years or older

Background and aimsElevated serum ferritin is associated with incident Type 2 diabetes (T2D), but the interactions between serum ferritin and genetic factors which may improve understanding underlying mechanism in the development of T2D are still unclear. We determined the gene–ferritin interactions on the development of T2D by genome-wide gene–ferritin interaction analyses.Methods and resultsA total of 3405 participants from two prospective cohorts of community living residents were included, and the median follow-time was 3.99 years. Genome-wide gene–ferritin interactions were analyzed using the joint test with two degrees of freedom and the interaction test with one degree of freedom. There were 18 SNPs selected in the joint test. Finally, four independent variants [rs355140 (LINC00312), rs4075576 (nearby PDGFA), rs1332202 (PTPRD), and rs713157 (nearby LINC00900)] with low pairwise linkage disequilibrium (r2 < 0.2) and located at least 1000 kb from the index SNP showed interactions with serum ferritin level. In the association analyses between serum ferritin levels (tertiles of ferritin and ferritin status) and the incidence of T2D according to genotype, the Incidence Rate Ratios (IRRs) in the highest tertile of ferritin level (vs. the lowest tertile) were greater for participants with heterozygotes of risk alleles of each of the four SNP than IRRs for those with wild type. Compared with the normal group, the elevated ferritin group also had a higher risk of T2D for all genetic variants of risk alleles, particularly its homozygotes.ConclusionSerum ferritin level interacts with genetic variants (rs355140, rs4075576, rs1332202, and rs713157) in the development of T2D.     

脑卒中幸存者运动依从性影响因素质性研究的Meta整合

目的 系统整合脑卒中幸存者运动依从性的影响因素。方法 计算机检索PubMed、Web of Science、Cochrane library、Embase、CINAHL、PsycINFO、百度、Google、中国期刊全文数据库、万方数据库、中国生物医学数据库和维普中文期刊数据库中有关脑卒中运动依从性影响因素的相关研究,检索时间自建库至2021年11月15日。2名研究员独立筛选、提取、评价文献,遇到分歧小组协商讨论。结果 纳入符合标准的文献13篇,共提炼出完整的研究主题62个,归纳组合形成6个新的类别,2个综合的整合结果。整合结果1： 影响脑卒中患者运动依从性的个人因素;包括个人动机因素,个人能力因素及个人心理因素;整合结果2：影响脑卒中患者运动依从性的外在因素;包括人际关系因素、康复团队因素及社会系统因素。结论 深入理解影响卒中患者康复运动依从性的驱动和阻碍因素,找准提高康复运动依从性的突破口,进而提高患者的运动积极性,提高其生活质量。     

Access to mechanical thrombectomy for cerebral ischaemia: A population-based study in the North-of-France

Background and purposeHospitals admitting acute strokes should offer access to mechanical thrombectomy (MT), but local organisations are still based on facilities available before MT was proven effective. MT rates and outcomes at population levels are needed to adapt organisations. We evaluated rates of MT and outcomes in inhabitants from the North-of-France (NoF) area.MethodWe prospectively evaluated rates of MT and outcomes of patients at 3 months, good outcomes being defined as a modified Rankin scale (mRS) 0 to 2 or like the pre-stroke mRS.ResultsDuring the study period (2016–2017), 666 patients underwent MT (454, 68.1% associated with intravenous thrombolysis [IVT]). Besides, 1595 other patients received IVT alone. The rate of MT was 81 (95% confidence interval [CI] 72–90) per million inhabitants-year, ranging from 36 to 108 between districts. The rate of IVT was 249 (95% CI 234–264) per million inhabitants-year, ranging from 155 to 268. After 3 months, 279 (41.9%) patients who underwent MT had good outcomes, and 167 (25.1%) had died. Patients living outside the district of Lille where the only MT centre is, were less likely to have good outcomes at 3 months, after adjustment on age, sex, baseline severity, and delay.ConclusionThe rate of MT is one of the highest reported up to now, even in low-rate districts, but outcomes were significantly worse in patients living outside the district of Lille, and this is not only explained by the delay.     

Homocysteine might increase the risk of recurrence in patients presenting with primary cerebral infarction

Purpose: Although hyperhomocysteinemia (Hhcy) is a risk factor for cerebral infarction, its effect on recurrent cerebral infarction is less-defined. We aimed to investigate the association of Hhcy and increased risk of recurrent cerebral infarct.

Materials and methods: From 2011 to 2013, we recruited 231 primary cerebral infarct patients that were divided to a Hhcy group (n?=?105) and a control group (n?=?126) according to plasma homocysteinemia (Hcy) levels exceeding 15?μmol/L. In this prospective study, risk factors such as gender, age, blood lipid and glucose levels, history of diabetes, high blood pressure, smoking habits and plasma Hhcy levels were determined. A three-year follow-up compared differences in cerebral infarction recurrence rates. Statistical analyses identified whether plasma Hhcy levels were an independent risk factor for recurrent cerebral infarction.

Results: Triglyceride and low-density lipoprotein (LDL) levels in the Hhcy group were significantly higher than controls, and cerebral infarct recurrence rates in the Hhcy group exceeded control subject rates through the three-year follow-up (p?=?.021, p?=?.036 and p?=?.025). Cox proportional hazards modeling showed that elevated Hhcy levels (hazard ratio [HR]?=?3.062, p?<?.001), increased age (HR?=?1.069, p?<?.01), circulating triglyceride levels (HR?=?1.686, p?=?.048), and relative National Institutes of Health Stroke (NIHSS) score (HR?=?1.068, p?=?.016) were risk factors for recurrent cerebral infarction.

Conclusions: Level of Hhcy was a risk factor for recurrent cerebral infarction. Further, particular demographic and clinical outcomes including age, relative NIHSS scores, and circulating triglyceride levels were markedly associated with the occurrence of cerebral infarction.