Respiratory motion correction for image-guided cardiac interventions using 3-D echocardiography

In this paper, we investigate the use of 3-D echocardiography (echo) data for respiratory motion correction of roadmaps in image-guided cardiac interventions. This is made possible by tracking and calibrating the echo probe and registering it to the roadmap coordinate system. We compare two techniques. The first uses only echo–echo registration to predict a motion-correction transformation in roadmap coordinates. The second combines echo–echo registration with a model of the respiratory motion of the heart. Using experiments with cardiac MRI and 3-D echo data acquired from eight volunteers, we demonstrate that the second technique is more robust than the first, resulting in motion-correction transformations that were accurate to within 5 mm in 60% of cases, compared to 42% for the echo-only technique, based on subjective visual assessments. Objective validation showed that the model-based technique had an accuracy of 3.3 ± 1.1 mm, compared to 4.1 ± 2.2 mm for the echo only technique. The greater errors of the echo-only technique were mostly found away from the area of echo coverage. The model-based technique was more robust away from this area, and also has significant benefits in terms of computational cost.     

Comparison of three PCR methods for detection of Helicobacter pylori DNA and detection of cagA gene in gastric biopsy specimens

AIM:To comparatively evaluate PCR and other diagnosticmethods (the rapid urease test and/or culture) in order todetermine which of the three PCR methods (ureA,glmMand 26-kDa,SSA gene) was most appropriate in the diagnosisof Helicobacterpylori(Hpylori) infection and also to evaluatethe detection of a putative virulence marker of H pylori,thecage,gene,by PCR in biopsy specimens.METHODS:One hundred and eighty-nine biopsy specimenswere collected from 63 patients (three biopsies each)undergoing upper gastroduodenal endoscopy for variousdyspeptic symptoms.The PCR methods used to detectH pylori DNA directly from biopsies were the glmM,26-kDa,ureA and then cagA was used to compare the culturetechnique and CLO for urease with the culture techniquebeing used as the gold standard.RESULTS:Thirty-five percent of the biopsies were positivefor H pylori DNA using the 3 PCR methods,while 68% ofthese were positive for the cagA gene.Twenty-four percentof the biopsies were negative for H pylori DNA in all PCRmethods screened.The remaining 41% were either positivefor ureA gene only,glmM only,26-kDa only,or ureA glmM,ureA 26-kDa,glmM 26-kDa.Out of the 35% positivebiopsies,41% and 82% were positive by culture and CLOrespectively,while all negative biopsies were also negativeby culture and cagA.Cag A infection was also predominantlyfound in H pylori DNA of the biopsies irrespective of theclinical diagnosis.CONCLUSION:This method is useful for correctly identifyinginfections caused by H pylori and can be easily applied inour laboratory for diagnostic purposes.     

Willingness to accept H1N1 pandemic influenza vaccine: A cross-sectional study of Hong Kong community nurses

Background  

The 2009 pandemic of influenza A (H1N1) infection has alerted many governments to make preparedness plan to control the spread of influenza A (H1N1) infection. Vaccination for influenza is one of the most important primary preventative measures to reduce the disease burden. Our study aims to assess the willingness of nurses who work for the community nursing service (CNS) in Hong Kong on their acceptance of influenza A (H1N1) influenza vaccination.     

A novel Bayesian respiratory motion model to estimate and resolve uncertainty in image-guided cardiac interventions

In image-guided cardiac interventions, respiratory motion causes misalignments between the pre-procedure roadmap of the heart used for guidance and the intra-procedure position of the heart, reducing the accuracy of the guidance information and leading to potentially dangerous consequences. We propose a novel technique for motion-correcting the pre-procedural information that combines a probabilistic MRI-derived affine motion model with intra-procedure real-time 3D echocardiography (echo) images in a Bayesian framework. The probabilistic model incorporates a measure of confidence in its motion estimates which enables resolution of the potentially conflicting information supplied by the model and the echo data. Unlike models proposed so far, our method allows the final motion estimate to deviate from the model-produced estimate according to the information provided by the echo images, so adapting to the complex variability of respiratory motion. The proposed method is evaluated using gold-standard MRI-derived motion fields and simulated 3D echo data for nine volunteers and real 3D live echo images for four volunteers. The Bayesian method is compared to 5 other motion estimation techniques and results show mean/max improvements in estimation accuracy of 10.6%/18.9% for simulated echo images and 20.8%/41.5% for real 3D live echo data, over the best comparative estimation method.     

Anti‐inflammatory effects of exendin‐4, a glucagon‐like peptide‐1 analog,on human peripheral lymphocytes in patients with type 2 diabetes

Aims/Introduction

Type 2 diabetes is characterized by dysregulation of immunity, oxidative stress and reduced incretin effects. Experimental studies suggest that glucagon‐like peptide (GLP‐1) might have immunomodulating effects. We hypothesize that GLP‐1 receptor agonist, exendin‐4, might reduce inflammatory response in type 2 diabetes.

Materials and Methods

Using peripheral blood mononuclear cells (PBMC) sampled from 10 type 2 diabetes and 10 sex‐ and age‐matched control subjects and supernatants from PBMC culture, the expression of phospho‐mitogen activated protein kinase (MAPK) signaling pathways in CD4+ T helper lymphocytes and monocytes was analyzed using flow cytometry. Cytokines/chemokines and superoxide anion before and after treatment with exendin‐4 were measured by cytometric bead array and chemiluminesence assay, respectively.

Results

Compared with control subjects, PBMC from type 2 diabetes patients showed activated MAPK (P38, c‐Jun NH2‐terminal protein kinase and extracellular signal‐regulated kinase) signaling pathway, elevated superoxide anion, increased pro‐inflammatory cytokines (tumor necrosis factor‐α, interleukin‐1β, interleukin‐6) and chemokines (CCL5/regulated on activation normal T‐cell expressed and secreted and CXCL10/interferon‐γ‐induced protein 10). These changes were attenuated by exendin‐4, possibly through the suppression of p38 MAPK.

Conclusions

These results suggest that exendin‐4 might downregulate pro‐inflammatory responses and reduce oxidative stress by suppressing MAPK signaling pathways in type 2 diabetes.