Quantification accuracy for dynamic contrast enhanced (DCE) CT imaging: phantom and quality assurance framework

PURPOSE

Standardization and protocol optimization is essential for quantification of Dynamic Contrast Enhanced CT as an imaging biomarker. Currently, no commercially available quality assurance (QA) phantoms can provide for testing a complete set of imaging parameters pertaining to routine quality control for contrast-enhanced (CE) CT, as well as spatiotemporal accuracy. The purpose of this work was, therefore: (a) developing a solid calibration phantom for routine CE CT quality assurance; (b) investigating the sensitivity of CECT to organ motion, and (c) characterizing a volumetric CT scanner for CECT.

METHODS

CECT calibration phantom consisting of an acrylic uniform cylinder containing multiple capsules of varying diameters and orientations was designed and built. The capsules contain different solid density materials mimicking iodine contrast enhancement. Sensitivity and accuracy of CECT measurements on all capsules was performed using a 320-slice CT scanner for a range of scan parameters both with and without phantom motion along the transaxial axis of the scanner.

RESULTS

Routine commissioning tests such as uniformity, spatial resolution and image noise were successfully determined using the CECT phantom. Partial volume effect and motion blurring both contribute to a general decrease in contrast enhancement and this was further dependent on capsule orientation (least pronounced for the transaxial orientation). Scanning with a rotation time of less than 0.5 s, the effect of blurring is less than 3% for all orientations and phantom speeds.

CONCLUSION

A new robust contrast calibration phantom was developed and used to evaluate the performance of a 320-slice volumetric CT scanner for DCE-CT.

Review article: Asia-Pacific consensus recommendations on endoscopic tissue acquisition for biliary strictures

BACKGROUND

Pre-operative tissue diagnosis for suspected malignant biliary strictures remains challenging.

AIM

To develop evidence-based consensus statements on endoscopic tissue acquisition for biliary strictures.

METHODS

The initial draft of statements was prepared following a systematic literature review. A committee of 20 experts from Asia-Pacific region then reviewed, discussed, and modified the statements. Two rounds of independent voting were conducted to reach a final version. Consensus was considered to be achieved when 80% or more of voting members voted "agree completely" or "agree with some reservation."

RESULTS

Eleven statements achieved consensus. The choice of tissue sampling modalities for biliary strictures depends on the clinical setting, the location of lesion, and availability of expertise. Detailed radiological and endoscopic evaluation is useful to guide the selection of appropriate tissue acquisition technique. Standard intraductal biliary brushing and/or forceps biopsy is the first option when endoscopic biliary drainage is required with an overall (range) sensitivity and specificity of 45% (26%-72%) and 99% (98%-100%), and 48% (15%-100%) and 99% (97%-100%), respectively, in diagnosing malignant biliary strictures. Probe-based confocal laser endomicroscopy and fluorescence in situ hybridisation using 4 fluorescent-labelled probes targeting chromosomes 3, 7, 17 and 9p21 locus may be added to improve the diagnostic yield. Cholangioscopy-guided biopsy and EUS-guided tissue acquisition can be considered after prior negative conventional tissue sampling with an overall (range) sensitivity and specificity of 60% (38%-88%) and 98% (83%-100%), and 80% (46%-100%) and 97% (92%-100%), respectively, in diagnosing malignant biliary strictures.

CONCLUSION

These consensus statements provide evidence-based recommendations for endoscopic tissue acquisition of biliary strictures.

Abstract 4479: Protein arginine methyltransferase PRMT6 regulates cancer stemness through CRAF methylation in hepatocellular carcinoma

Arginine methylation is a post-translational modification that plays pivotal roles in signal transduction and gene transcription during cell fate determination. We found protein methyltransferase 6 (PRMT6) to be frequently down-regulated in hepatocellular carcinoma (HCC) cells and its expression to negatively correlate with aggressive cancer features in HCC patients. Silencing of PRMT6 promoted the tumor-initiating, metastasis and therapy resistance potential of HCC cells. Consistently, loss of PRMT6 expression aggravated liver tumorigenesis in a DEN+CCL4 HCC induced PRMT6-/- mouse model. Integrated transcriptome and protein-protein interaction studies revealed an enrichment of genes implicated in RAS signaling and that PRMT6 interacted with CRAF, and likely other RAF family members, and their methylation at conserved arginine 100, negatively regulating its activity, and as a consequence resulting in enhanced MEK/ERK signaling. Our work uncovered a critical repressive function for PRMT6 in maintenance of HCC cells by regulating the MEK/ERK pathway via arginine methylation of RAF, providing a new avenue of molecular mechanism by which ERK mediated stemness in HCC cells are developed.

Citation Format: LH Chan, L Zhou, Kai Yu Ng, TL Wong, TK Lee, YP Ching, YF Yuan, D Xie, S Richard, MS Huen, XY Guan, S Ma. Protein arginine methyltransferase PRMT6 regulates cancer stemness through CRAF methylation in hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4479.

[Management programs on diabetes among Chinese adults in the National Demonstration Areas for Comprehensive Prevention and Control of Non-communicable Diseases]

Objective: To understand the current situation on management of diabetes mellitus patients aged 35 and above in the National Demonstration Areas for Comprehensive Prevention and Control of Non-communicable Diseases, in China. Methods: Local residents, aged 18 years and above were randomly selected by a complex, multistage, probability sampling method. Face-to-face questionnaire survey was carried out between November and December 2016. Rates regarding prevalence, treatment and management of diabetes were calculated, and influencing factors of diabetes were analyzed by using the non-conditional logistic regression model. Results: A total of 3 213 residents aged ≥35 years were included in this study, of which 11.48% (369/3 213) reported that they had ever been informed by a doctor or other health worker that their blood sugar level was high or being diabetic. The rate of self-reported treatment among the diabetic patients was 83.20% (307/369). Rates on overall management and standardized management were 69.92% (258/369) and 53.66% (198/369), respectively. Higher rates were seen in residents aged 55 to 64 years, 76.32% for overall management and 59.65% for standardized management. Through multiple logistic regression analysis, we found that standardized management for diabetes was much higher in the Demonstration Areas located in the eastern areas (OR=2.942, 95%CI: 1.547-5.594), or patients with characteristics including high implementation score (OR=3.499, 95%CI: 1.865-6.563), already signed family doctors (OR=5.661, 95%CI: 3.237-9.899), or without hypertension (OR=1.717, 95%CI: 1.010- 2.920). Residents who were living in the first and second batch areas of implementation or responding to the NCDs with positive attitude were more likely to accept standardized management. Conclusion: Prevention and management programs on diabetes had met the requirements set for the Demonstration Areas which had promoted the specific implementation and further development of standardized management on diabetes.

[Study on the overall implementation status of the National Demonstration Areas for Comprehensive Prevention and Control of Non-communicable Diseases]

Objective: To understand the current overall status of implementation on the National Demonstration Areas of Comprehensive Prevention and Control of Non-communicable Diseases. Methods: According to the scheme design of the questionnaires, all the National Demonstration Areas were involved in this study. For each National Demonstration Areas, eight departments were selected to complete a total of 12 questionnaires. Results: Scores related to the implementation of the National Demonstration Areas accounted for 71.8% of the total 170 points. Based on the scores gathered from this study, the 23-items-index-system that represented the status of project implementation was classified into seven categories. Categories with higher percentile scores would include: monitoring (88.0%), safeguard measures (75.0%), health education and health promotion (75.0%). Categories with lower percentile scores would include: the national health lifestyle actions (67.7%), community diagnosis (66.7%), discovery and intervention of high-risk groups (64.7%), and patient management (60.9%). There were significant differences noticed among the eastern, central and western areas on items as safeguard measures, health education/promotion, discovery and intervention of high-risk groups. In all, the implementation programs in the eastern Demonstration Areas seemed better than in the central or western regions. As for the 23 items, five of the highest scores appeared on policy support, mortality surveillance, tumor registration, reporting system on cardiovascular/cerebrovascular events, and on tobacco control, respectively. However, the lowest five scores fell on healthy diet, patient self-management program, oral hygiene, setting up the demonstration units and promotion on basic public health services, respectively. The overall scores in the eastern region was higher than that in the central or the western regions. The scores in the central and western regions showed basically the same. Conclusions: The overall status of implementation on the National Demonstration Areas was satisfactory. Future attention should be focusing on patient management as well as discovery and intervention of high-risk groups, which also presented the lowest scores, in this survey.

[Application of autoregressive integrated moving average model in predicting the reported notifiable communicable diseases in China]

Objective: To develop the models for predicting the reported legally notifiable diseases in China. Autoregressive integrated moving average (ARIMA) model was applied to forecast the trend of diseases. Methods: Cases used for building the model were from of the records of Notifiable Infectious Diseases in China from May 2009 to July 2016 with R software and the model's predictive ability was tested by the data from August 2016 to January 2017. Results: A strong seasonal nature was seen in the reported cases of notifiable communicable diseases, with the lowest point in February and highest peak in June. ARIMA (4, 1, 0) (1, 1, 1)(12) model was established by the team to forecast the notifiable communicable diseases. Data showed that the biggest and lowest relative errors appeared as 9.78% and 2.21%, respectively, with the mean of the relative error as 5.39%. Conclusion: Based on the results of this study, the ARIMA (4, 1, 0) (1, 1, 1)(12) model seemed to have had the sound prediction of notifiable communicable diseases in China.

Discussion of “The Evolution of Boosting Algorithms” and “Extending Statistical Boosting”

This article is part of a For-Discussion-Section of Methods of Information in Medicine about the papers “The Evolution of Boosting Algorithms – From Machine Learning to Statistical Modelling” [1] and “Extending Statistical Boosting – An Overview of Recent Methodological Developments” [2], written by Andreas Mayr and co-authors. It is introduced by an editorial. This article contains the combined commentaries invited to independently comment on the Mayr et al. papers. In sub-sequent issues the discussion can continue through letters to the editor.

Clinical features and outcomes in secondary adult hemophagocytic lymphohistiocytosis

BACKGROUND

Hemophagocytic lymphohistiocytosis (HLH) is a rare clinical syndrome characterized by an infrequent but immune-mediated life-threatening disease, with confusing clinical manifestations, rapidly deteriorating health, high morbidity and mortality and challenging diagnosis.

AIM

The purpose of this study was to improve the recognition and understanding of HLH.

DESIGN

Retrospective observational cross-sectional study.

METHODS

Data were collected for all cases of adult patients diagnosed with HLH in a large cohort managed at a single medical center from January 2011 to December 2015.

RESULTS

The median age was 52 years (range 18-90 years) and 123 (60.0%) were male. Over 95% patients manifested fever, hyperferritinemia and elevated lactate dehydrogenase. Underlying triggers of HLH were as follows: 119 (58.0%) malignancies, 83 (40.5%) infections, 14 (6.8%) unknown triggers and 14 (6.8%) autoimmune disorders. The median overall survival was 55 days. And elderly patients (age ≥60 years) had a markedly worse survival compared with young patients (age <60 years) (median overall survival 24 days vs. 159 days, respectively; P <0.001). In a multivariable analysis, platelet <40 × 109/l (HR = 2.534; 95% CI 1.152-5.573; P = 0.021), PT prolonged >3 s (HR = 1.909; 95% CI 1.127-3.234; P = 0.016) and malignancy (HR = 1.614; 95% CI 1.008-2.582; P = 0.046) were correlated with poor survival.

CONCLUSION

HLH adult patients had very complex clinical manifestations as well as underlying diseases. Patients with PLT <40 ×109/l, PT prolonged >3 s and malignancy had inferior survival. It is of great importance to improve our understanding of this syndrome.

Aberrant Thalamocortical Connectivity in Juvenile Myoclonic Epilepsy

The purpose of this study was to investigate the functional connectivity (FC) of thalamic subdivisions in patients with juvenile myoclonic epilepsy (JME). Resting state functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) data were acquired from 22 JME and 25 healthy controls. We first divided the thalamus into eight subdivisions by performing independent component analysis on tracking fibers and clustering thalamus-related FC maps. We then analyzed abnormal FC in each subdivision in JME compared with healthy controls, and we investigated their associations with clinical features. Eight thalamic sub-regions identified in the current study showed unbalanced thalamic FC in JME: decreased FC with the superior frontal gyrus and enhanced FC with the supplementary motor area in the posterior thalamus increased thalamic FC with the salience network (SN) and reduced FC with the default mode network (DMN). Abnormalities in thalamo-prefrontocortical networks might be related to the propagation of generalized spikes with frontocentral predominance in JME, and the network connectivity differences with the SN and DMN might be implicated in emotional and cognitive defects in JME. JME was also associated with enhanced FC among thalamic sub-regions and with the basal ganglia and cerebellum, suggesting the regulatory role of subcortical nuclei and the cerebellum on the thalamo-cortical circuit. Additionally, increased FC with the pallidum was positive related with the duration of disease. The present study provides emerging evidence of FC to understand that specific thalamic subdivisions contribute to the abnormalities of thalamic-cortical networks in JME. Moreover, the posterior thalamus could play a crucial role in generalized epileptic activity in JME.

Dusky works upstream of Four-jointed and Forked in wing morphogenesis in Tribolium castaneum

Dusky (dy) is required for cytoskeletal reorganization during wing morphogenesis in Drosophila melanogaster, but which genes participate together with dy for wing morphogenesis has remained unclear. In Tribolium castaneum, dy is highly expressed at the late embryonic stage. Tissue-specific expression analysis indicated high expression levels of dy in the epidermis, head and fat body of late-stage larvae. RNA interference (RNAi) targeting dy significantly decreased adult wing size and caused improper folding of the elytra. Meanwhile, dy knockdown reduced the transcription of four-jointed (fj) and forked (f). Our results show that fj RNAi reduces adult wing size and that silencing f results in abnormal wing folding in T. castaneum. Interestingly, knocking down fj and f simultaneously phenocopies dy RNAi, suggesting that dy probably acts upstream of fj and f to regulate wing morphogenesis in T. castaneum.

[Current status of folic acid supplementation in women at child-bearing age in suburban area of Beijing]

Objective: To access the current status of folic acid supplementation in women at childbearing age in suburban area of Beijing, 2016. Methods: In this cross-sectional study, a total of 722 women aged 17-41 years from six hospitals in suburban areas of Beijing were selected through cluster sampling. A questionnaire survey was conducted. Results: The rates of folic acid intake and regular folic acid intake among women under survey were 63.9% (456/714) and 83.3% (380/456). In women who remembered the duration of folic acid supplementation, the overall rate of preconceptional folic acid supplementation was 35.5% (159/450), in whom 27.3% (123/450) began to take folic acid 0-3 months before pregnancy; 8.0% (36/450) began to take folic acid 3 months before pregnancy. Multivariate logistic regression analysis indicated that household registering type, preparation for pregnancy or pregnancy, parity, smoking and alcohol use were the influencing factors for folic acid supplementation. Conclusions: The rate of folic acid supplementation remained low in childbearing aged women in suburban area of Beijing. It is necessary to further strengthen the health education about the importance of folic acid supplementation to improve the intake rate and the regular intake rate of folic acid in pregnant women and to promote maternal infant health and reduce the related complications.

Microindentation - a tool for measuring cortical bone stiffness? A systematic review

Objectives

Microindentation has the potential to measure the stiffness of an individual patient’s bone. Bone stiffness plays a crucial role in the press-fit stability of orthopaedic implants. Arming surgeons with accurate bone stiffness information may reduce surgical complications including periprosthetic fractures. The question addressed with this systematic review is whether microindentation can accurately measure cortical bone stiffness.

Methods

A systematic review of all English language articles using a keyword search was undertaken using Medline, Embase, PubMed, Scopus and Cochrane databases. Studies that only used nanoindentation, cancellous bone or animal tissue were excluded.

Results

A total of 1094 abstracts were retrieved and 32 papers were included in the analysis, 20 of which used reference point indentation, and 12 of which used traditional depth-sensing indentation. There are several factors that must be considered when using microindentation, such as tip size, depth and method of analysis. Only two studies validated microindentation against traditional mechanical testing techniques. Both studies used reference point indentation (RPI), with one showing that RPI parameters correlate well with mechanical testing, but the other suggested that they do not.

Conclusion

Microindentation has been used in various studies to assess bone stiffness, but only two studies with conflicting results compared microindentation with traditional mechanical testing techniques. Further research, including more studies comparing microindentation with other mechanical testing methods, is needed before microindentation can be used reliably to calculate cortical bone stiffness.

Cite this article: M. Arnold, S. Zhao, S. Ma, F. Giuliani, U. Hansen, J. P. Cobb, R. L. Abel, O. Boughton. Microindentation – a tool for measuring cortical bone stiffness? A systematic review. Bone Joint Res 2017;6:542–549. DOI: 10.1302/2046-3758.69.BJR-2016-0317.R2.

High-dose dexamethasone or all-trans-retinoic acid restores the balance of macrophages towards M2 in immune thrombocytopenia

Essentials M1/M2 imbalance is involved in many autoimmune diseases, and could be restored. The expressions and functions of M1 and M2 were investigated in an in vitro culture system. A preferred M1 polarization is involved in the pathogenesis of immune thrombocytopenia (ITP). High-dose dexamethasone or all-trans-retinoic acid restores M1/M2 balance in ITP patients.

SUMMARY

Background Immune thrombocytopenia (ITP) is an autoimmune disorder. Deficiency of immune tolerance in antigen-presenting cells and cross-communication between antigen-presenting cells and T cells are involved in the pathogenesis of ITP. Macrophages can polarize into proinflammatory M1 or anti-inflammatory M2 phenotypes in response to different environmental stimuli, and have diverse immunologic functions. Objectives To investigate the M1/M2 imbalance in ITP and whether high-dose dexamethasone (HD-DXM) or all-trans-retinoic acid (ATRA) could restore this imbalance. Methods The numbers of M1 and M2 macrophages in the spleens of ITP patients and patients with traumatic spleen rupture were analyzed by immunofluorescence. Monocyte-derived macrophages were cultured and induced with cytokines and drugs. The expression of M1 and M2 markers and functions of M1 and M2 macrophages before and after modulation by HD-DXM or ATRA were evaluated with flow cytometry and ELISA. Results There was preferred M1 polarization in ITP spleens as compared with healthy controls. Monocyte-derived macrophages from ITP patients had increased expression of M1 markers and impaired immunosuppressive functions. Either HD-DXM or ATRA corrected this imbalance by decreasing the expression of M1 markers and increasing the expression of M2 markers. Moreover, HD-DXM-modulated or ATRA-modulated macrophages suppressed both CD4+ and CD8+ T-cell proliferation and expanded CD4+ CD49+ LAG3+ type 1 T-regulatory cells. HD-DXM or ATRA modulated macrophages to shift the T-cell cytokine profile towards Th2. Treating patients with HD-DXM or ATRA revealed that macrophages induced from responders showed a predominant M2-like phenotype and immunosuppressive function. Conclusions Aberrant macrophage polarization is involved in the pathogenesis of ITP. Either HD-DXM or ATRA is able to correct this imbalance.