Repeatability of IVIM biomarkers from diffusion-weighted MRI in head and neck:Bayesian probability versus neural network

Purpose: The intravoxel incoherent motion (IVIM) model for DWI might provide useful biomarkers for disease management in head and neck cancer. This study compared the repeatability of three IVIM fitting methods to the conventional nonlinear least-squares regression: Bayesian probability estimation, a recently introduced neural network approach, IVIM-NET, and a version of the neural network modified to increase consistency, IVIM-NETmod. Methods: Ten healthy volunteers underwent two imaging sessions of the neck, two weeks apart, with two DWI acquisitions per session. Model parameters (ADC, diffusion coefficient (Formula presented.), perfusion fraction (Formula presented.), and pseudo-diffusion coefficient (Formula presented.)) from each fit method were determined in the tonsils and in the pterygoid muscles. Within-subject coefficients of variation (wCV) were calculated to assess repeatability. Training of the neural network was repeated 100 times with random initialization to investigate consistency, quantified by the coefficient of variance. Results: The Bayesian and neural network approaches outperformed nonlinear regression in terms of wCV. Intersession wCV of (Formula presented.) in the tonsils was 23.4% for nonlinear regression, 9.7% for Bayesian estimation, 9.4% for IVIM-NET, and 11.2% for IVIM-NETmod. However, results from repeated training of the neural network on the same data set showed differences in parameter estimates: The coefficient of variances over the 100 repetitions for IVIM-NET were 15% for both (Formula presented.) and (Formula presented.), and 94% for (Formula presented.); for IVIM-NETmod, these values improved to 5%, 9%, and 62%, respectively. Conclusion: Repeatabilities from the Bayesian and neural network approaches are superior to that of nonlinear regression for estimating IVIM parameters in the head and neck

Standardisation of magnetic nanoparticles in liquid suspension

Suspensions of magnetic nanoparticles offer diverse opportunities for technology innovation, spanning a large number of industry sectors from imaging and actuation based applications in biomedicine and biotechnology, through large-scale environmental remediation uses such as water purification, to engineering-based applications such as position-controlled lubricants and soaps. Continuous advances in their manufacture have produced an ever-growing range of products, each with their own unique properties. At the same time, the characterisation of magnetic nanoparticles is often complex, and expert knowledge is needed to correctly interpret the measurement data. In many cases, the stringent requirements of the end-user technologies dictate that magnetic nanoparticle products should be clearly defined, well characterised, consistent and safe; or to put it another way—standardised. The aims of this document are to outline the concepts and terminology necessary for discussion of magnetic nanoparticles, to examine the current state-of-the-art in characterisation methods necessary for the most prominent applications of magnetic nanoparticle suspensions, to suggest a possible structure for the future development of standardisation within the field, and to identify areas and topics which deserve to be the focus of future work items. We discuss potential roadmaps for the future standardisation of this developing industry, and the likely challenges to be encountered along the way

Taxonomy of the family Arenaviridae and the order Bunyavirales: update 2018

In 2018, the family Arenaviridae was expanded by inclusion of 1 new genus and 5 novel species. At the same time, the recently established order Bunyavirales was expanded by 3 species. This article presents the updated taxonomy of the family Arenaviridae and the order Bunyavirales as now accepted by the International Committee on Taxonomy of Viruses (ICTV) and summarizes additional taxonomic proposals that may affect the order in the near future

Conversion of osteoporotic vertebral fracture severity score to osteoporosis T-score equivalent status: a framework and a comparative study of Hong Kong Chinese and Rome Caucasian older women

We explored how the severity of radiological osteoporotic vertebral fracture (OVF) can be converted to the equivalent T-score values.Introduction To perform a study to define what portion of older community women with what severity of radiographic OVF correspond to what low T-score status.Methods There were age-matched 301 Italian community women and 301 Chinese community women (sub-group A, age, 73.6 +/- 6.1 years). In addition, Chinese sub-groups B and C included 110 community women (age, 68.9 +/- 5.5 years) and 101 community women (age: 82.2 +/- 4.3 years), respectively. For each vertebra in women, a score of 0, - 0.5, - 1, - 1.5, - 2, - 2.5, and - 3 was assigned for no OVF or OVF of < 20%, >= 20 similar to 25%, >= 25% similar to 1/3, >= 1/3 similar to 40%, >= 40%-2/3, and >= 2/3 vertebral height loss, respectively, OVFss was defined as the summed score of vertebrae T4 to L5. OVFss and T-scores were ranked from the smallest to the largest values.Results For the Chinese total group (sub-groups A, B, and C together), OVFss = - 1 corresponded to lowest T-score (lowest T-score of lumbar spine, femoral neck, and total hip) of - 3.4 similar to - 3.2. OVFss <= - 1.5 corresponded to femoral neck T-score <= - 2.5. OVFss = -1.5 corresponded to a mean femoral neck T-score of - 3.0, - 2.6, and - 2.4, among Chinese sub-groups B, A, and C subjects, respectively. For Italians, all cases with OVFss <= - 1 had lowest T-score <= - 2.5. For cases with femoral neck T-score = - 2.5, 41.7% had OVFss = - 1.5, and 58.3% had OVFss = - 1.Conclusion For older women, statistically OVFss <= -1 suggests this subject is osteoporotic according to lowest T-score. If using femoral neck T-score, OVFss <= - 1.5 qualifies osteoporosis diagnosis

Much lower prevalence and severity of osteoporotic vertebral facture in elderly Chinese women than in age-matched Italian women: a radiographic comparison study.

Introduction: Many studies reported that East Asian's prevalence of radiographic OVF is similar to that of Caucasian. Since elderly Chinese's osteoporotic hip fracture prevalence is half (or less than half) of that of their age-match Caucasians, we hypothesize that elderly Chinese's OVF prevalence could be only half, or even less than half, of that of their agematch Caucasians.Materials: Age-matched elderly women's radiographs (T4-L5) were from two OVF population-based epidemiological studies conducted in Hong Kong (n=200) and in Rome (n=200). The study subjects had a mean age of 74.1 yrs (range: 65-87 yrs). All radiographs were double read by one reader in Hong Kong and one reader in Rome. Radiological osteoporotic vertebral deformity (ROVD) classification included no ROVD (grade 0), and ROVDs with <20%, 20~25%, ≥25%~1/3, ≥1/3~40%, ≥40%~2/3, and ≥2/3 height loss (grade 1~6). Spinal deformity index (SDI) was calculated with each vertebra assigned a score of 0, 0.5, 1, 1.5, 2, 2.5 and 3 for no ROVD or ROVDs grade 1~6.Results: 77 (38.5%) Chinese subjects and 123 Italian subjects (61.5%) had ROVD respectively (p<0.0001). ROVDs in Italian subjects tended to be more severe (total and mean SDI: 454.5 and 3.71 for Italian, and 212 and 2.72 for Chinese, p<0.05), more likely to be multiple (p<0.001), more likely to have severe and collapsed grades (p<0.001). The slope of the relationship between age vs. SDI was steeper for the Italian subjects than for the Chinese subjects, suggesting aging Italian subjects developed faster for the prevalence of ROVD and their severity. A trend suggested earlier onset of ROVD among Italian.Conclusion: Compared with elderly Italian women, elderly Chinese women have much lower prevalence of OVF. OVF in Chinese women tend to be less severe and less likely to have multiple fractures and less likely to collapse

An update on PET-based molecular imaging in neuro-oncology: Challenges and implementation for a precision medicine approach in cancer care

PET imaging using novel radiotracers show promises for tumor grading and molecular characterization through visualizing molecular and functional properties of the tumors. Application of PET tracers in brain neoplasm depends on both type of the neoplasm and the research or clinical significance required to be addressed. In clinical neuro-oncology, 18F-FDG is used mainly to differentiate tumor recurrence from radiation-induced necrosis, and novel PET agents show attractive imaging properties. Novel PET tracers can offer biologic information not visible via contrast-enhanced MRI or 18F-FDG PET. This review aims to provide an update on the complementary role of PET imaging in neuro-oncology both in research and clinical settings along with presenting interesting cases in this context