Diffusion-weighted magnetic resonance imaging in rat kidney using two-dimensional navigated,interleaved echo-planar imaging at 7.0 T

The purpose of this study was to investigate the feasibility of two-dimensional (2D) navigated, interleaved multishot echo-planar imaging (EPI) to enhance kidney diffusion-weighted imaging (DWI) in rats at 7.0 T. Fully sampled interleaved four-shot EPI with 2D navigators was tailored for kidney DWI (Sprague–Dawley rats, n = 7) on a 7.0-T small bore preclinical scanner. The image quality of four-shot EPI was compared with T₂-weighted rapid acquisition with relaxation enhancement (RARE) (reference) and single-shot EPI (ss-EPI) without and with parallel imaging (PI). The contrast-to-noise ratio (CNR) was examined to assess the image quality for the EPI approaches. The Dice similarity coefficient and the Hausdorff distance were used for evaluation of image distortion. Mean diffusivity (MD) and fractional anisotropy (FA) were calculated for renal cortex and medulla for all DWI approaches. The corticomedullary difference of MD and FA were assessed by Wilcoxon signed-rank test. Four-shot EPI showed the highest CNR among the three EPI variants and lowest geometric distortion versus T₂-weighted RARE (mean Dice: 0.77 for ss-EPI without PI, 0.88 for ss-EPI with twofold undersampling, and 0.92 for four-shot EPI). The FA map derived from four-shot EPI clearly identified a highly anisotropic region corresponding to the inner stripe of the outer medulla. Four-shot EPI successfully discerned differences in both MD and FA between renal cortex and medulla. In conclusion, 2D navigated, interleaved multishot EPI facilitates high-quality rat kidney DWI with clearly depicted intralayer and interlayer structure and substantially reduced image distortion. This approach enables the anatomic integrity of DWI-MRI in small rodents and has the potential to benefit the characterization of renal microstructure in preclinical studies.     

Molecular imaging in oncology: Current impact and future directions

The authors define molecular imaging, according to the Society of Nuclear Medicine and Molecular Imaging, as the visualization, characterization, and measurement of biological processes at the molecular and cellular levels in humans and other living systems. Although practiced for many years clinically in nuclear medicine, expansion to other imaging modalities began roughly 25 years ago and has accelerated since. That acceleration derives from the continual appearance of new and highly relevant animal models of human disease, increasingly sensitive imaging devices, high-throughput methods to discover and optimize affinity agents to key cellular targets, new ways to manipulate genetic material, and expanded use of cloud computing. Greater interest by scientists in allied fields, such as chemistry, biomedical engineering, and immunology, as well as increased attention by the pharmaceutical industry, have likewise contributed to the boom in activity in recent years. Whereas researchers and clinicians have applied molecular imaging to a variety of physiologic processes and disease states, here, the authors focus on oncology, arguably where it has made its greatest impact. The main purpose of imaging in oncology is early detection to enable interception if not prevention of full-blown disease, such as the appearance of metastases. Because biochemical changes occur before changes in anatomy, molecular imaging—particularly when combined with liquid biopsy for screening purposes—promises especially early localization of disease for optimum management. Here, the authors introduce the ways and indications in which molecular imaging can be undertaken, the tools used and under development, and near-term challenges and opportunities in oncology.     

Accurate detection of reemergent anti-donor ABO antibody is crucial for safe transfusion in ABO major incompatible HSCT patient after achieved the stages of full switch to donor type

Dynamic monitoring ABO chimera including erythroid ABO antigen and anti-A/B is crucial to not only assess the status of erythroid engraftment but also achieve personalized safety transfusion in patients post ABO incompatible hematopoietic stem cell transplantation. Transfusion support for ABO incompatible (ABOi) HSCT patients after achieved complete alteration to donor origin still remains cautious because the instant hematopoietic status on these transplant patients possibly returned to patient origin derived from early disease relapse and graft loss or failure. We reported that reemergent anti-B in a female patients (donor/patient: B/O) at the early phase after achievement complete donor type were not effectively found from partial automatic ABO blood grouping systems, which directly resulted in differential judgement of transplantation stage for about 15 days and disturbed the optimal recommendation on transfusion support. Meanwhile, the solely alteration of ABO chimera was found and earlier than changes of other markers such as MRD diagnosis, chimerism analysis by STR-PCR and sex chromosome assays, which can be an available predictors for bad transplant outcomes such as graft failure.     

Magnetic resonance elastography with guided pressure waves

Magnetic resonance elastography aims to non-invasively and remotely characterize the mechanical properties of living tissues. To quantitatively and regionally map the shear viscoelastic moduli in vivo, the technique must achieve proper mechanical excitation throughout the targeted tissues. Although it is straightforward, ante manibus, in close organs such as the liver or the breast, which practitioners clinically palpate already, it is somewhat fortunately highly challenging to trick the natural protective barriers of remote organs such as the brain. So far, mechanical waves have been induced in the latter by shaking the surrounding cranial bones. Here, the skull was circumvented by guiding pressure waves inside the subject's buccal cavity so mechanical waves could propagate from within through the brainstem up to the brain. Repeatable, reproducible and robust displacement fields were recorded in phantoms and in vivo by magnetic resonance elastography with guided pressure waves such that quantitative mechanical outcomes were extracted in the human brain.     

An economic analysis of the cost of survival of micro preemies: A systematic review

ObjectiveThis study aimed to systematically review the current literature on the economic costs of micro preemie as well as evidence on the cost-effectiveness of interventions to improve outcomes for micro preemie babies with a birth weight of ≤500 g.MethodWe searched MEDLINE, CINAHL, Scopus, ECONLIT, Business Source Premier and Cochrane Library for studies reporting costs of micro preemie from January 2000. Costs were inflated to 2019 United States dollars (US$). All full-text articles were assessed for eligibility and a quality assessment of included articles was conducted using the Drummond and the Larg and Moss checklists.ResultsThe search identified three studies that met the inclusion criteria; two cost-of-illness studies and one cost-effectiveness study. Across studies, the mean healthcare spending per micro preemie survivor (in 2019 US$) ranged from US$61,310 (birth admission) to US$263,958 (inpatient and outpatient for the first six months of life). One modelling study reported exclusive human milk diet for micro preemies at birth was more cost-effective compared to the standard approach with cow milk diet from the third-party payer and societal perspectives.ConclusionDespite significant advances in perinatal care and expanded access to life-saving equipment to improve survival outcomes of micro preemie, there remains a paucity of research on economic costs associated with these babies. No study has utilised quality-adjusted life-years as an outcome measure. Given the chronic conditions and long-term neurologic disability associated with micro preemie survivors, an estimate of the lifetime cost to the individual, healthcare providers and society would provide a benchmark of the potential cost-savings that could accrue from cost-effective interventions to improve the survival rate of micro preemies.     

RWMAs in critically ill patients with non-obstructed coronary arteries

Introduction

Left ventricular (LV) dysfunction is estimated to occur in 10%–25% of the general intensive care unit (ICU) population and is frequently seen as regional wall motion abnormalities (RWMAs). Although RWMA is mostly attributed to myocardial ischemia or infarction, some studies have suggested that nonischemic RWMA might also be prevalent. We sought to establish that RWMA can be seen in critically ill patients with normal coronary arteries and to explore reasons for RWMA in this population.

Methods

In this retrospective study, data from the hospital angiography register and the ICU register were collated between 2012 and 2019. Patients were identified who underwent angiography in conjunction with their ICU stay and had RWMA on echocardiography. Patients were divided into either those with non-obstructed or those with obstructed coronary arteries. Cardiac magnetic resonance imaging (cMRI) examinations were reviewed if they had been performed on patients with non-obstructed coronaries.

Results

We identified 53 patients with RWMA and non-obstructed coronary arteries and 204 patients with RWMA and obstructed coronary arteries. Patients with non-obstructed coronary arteries were more often female, younger, and had fewer cardiovascular risk factors. They less commonly had ST elevation, but more frequently had T-wave inversion or serious arrhythmias. Troponin levels were higher in patients with obstructed coronary arteries, but NT-proBNP was similar between the groups. There were no differences in risk-adjusted 90-day mortality between patients with non-obstructed versus obstructed coronary arteries (OR 1.21, [95% CI 0.56–2.64], p = .628). In those with non-obstructed coronary arteries, follow-up echocardiography was available for 38 patients, of whom 30 showed normalization of cardiac function. Of the 14 patients with non-obstructed coronary arteries on whom cMRI was performed, 7 had a tentative diagnosis of Takotsubo syndrome or myocardial stunning; 4 had a myocardial infarction (preexisting in 3 cases); 1 patient had acute myocarditis; 1 patient had post-myocarditis; and 1 patient was diagnosed with dilated cardiomyopathy.

Conclusion

RWMA can be seen to occur in critically ill patients in the absence of coronary artery obstruction. Several conditions can cause regional hypokinesia, and cMRI is useful to evaluate the underlying etiology.     

Comparison of quantitative susceptibility mapping methods on evaluating radiation-induced cerebral microbleeds and basal ganglia at 3T and 7T

Quantitative susceptibility mapping (QSM) has the potential for being a biomarker for various diseases because of its ability to measure tissue susceptibility related to iron deposition, myelin, and hemorrhage from the phase signal of a T₂*-weighted MRI. Despite its promise as a quantitative marker, QSM is faced with many challenges, including its dependence on preprocessing of the raw phase data, the relatively weak tissue signal, and the inherently ill posed relationship between the magnetic dipole and measured phase. The goal of this study was to evaluate the effects of background field removal and dipole inversion algorithms on noise characteristics, image uniformity, and structural contrast for cerebral microbleed (CMB) quantification at both 3T and 7T. We selected four widely used background phase removal and five dipole field inversion algorithms for QSM and applied them to volunteers and patients with CMBs, who were scanned at two different field strengths, with ground truth QSM reference calculated using multiple orientation scans. 7T MRI provided QSM images with lower noise than did 3T MRI. QSIP and VSHARP + iLSQR achieved the highest white matter homogeneity and vein contrast, with QSIP also providing the highest CMB contrast. Compared with ground truth COSMOS QSM images, overall good correlations between susceptibility values of dipole inversion algorithms and the COSMOS reference were observed in basal ganglia regions, with VSHARP + iLSQR achieving the susceptibility values most similar to COSMOS across all regions. This study can provide guidance for selecting the most appropriate QSM processing pipeline based on the application of interest and scanner field strength.     

LncRNAs作为ceRNAs在肺癌中的研究进展

长链非编码RNAs(Long noncoding RNAs,lncRNAs)是一类长度在200~100000bp的非编码RNAs,蛋白编码能力缺乏或有限。近几年的研究表明,lncRNAs可通过竞争内源性RNAs(Competing endogenous RNAs,ceRNAs)的机制参与肿瘤细胞增殖、迁移、侵袭和凋亡,在肿瘤的发生发展中发挥重要的调控作用。而肺癌是发病率和死亡率最高的恶性肿瘤之一,严重威胁人类健康和生命安全。因此本文就lncRNAs形成的ceRNAs网络调控机制在肺癌方面的研究进行简要综述,为肺癌的诊断及治疗提供依据。