Using Virtual Reality to teach ultrasound-guided needling skills for regional anaesthesia: A randomised controlled trial.

STUDY OBJECTIVE: We previously designed and validated a virtual reality-based simulator to help train novices in ultrasound-guided needling skills necessary for safe and competent ultrasound-guided regional anaesthesia. This study was designed to compare the performance and error rates of novices trained by a human faculty aided with the assistance of this virtual reality simulator (virtual reality-assisted training), versus novices trained wholly by humans (conventional training). DESIGN, SETTING, AND PARTICIPANTS: In this single centre, randomised controlled study, we used a standardised teaching protocol, rigorous blinding, iterative training of assessors, and validated global rating scale and composite error score checklists to assess skills learning of novice participants. MAIN RESULTS: We recruited 45 novices and scored 270 assessments of performance and error rates. Inter-rater correlation coefficient of reliability of scoring between assessors for the global rating scale was 0.84 (95%CI 0.68-0.92) and for the composite error score checklist was 0.87 (95%CI 0.73-0.93). After adjustment for age, sex, Depression, Anxiety and Stress-21, and baseline score, there was no statistical difference for virtual reality-assisted training compared to conventional training in final global rating score (average treatment effect -3.30 (95%CI-13.07-6.48), p = 0.51) or in the final composite error score (average treatment effect 1.14 (95%CI -0.60-2.88), p = 0.20). Realism in the virtual reality simulator was similar to real-life when measured by the Presence Questionnaire, all components p > 0.79; and task workload assessed by the NASA-Task Load Index was not statistically different between groups, average treatment effect 5.02 (95%CI -3.51-13.54), p = 0.25. Results were achieved in the virtual reality-assisted group with half the human faculty involvement. CONCLUSION: Novices trained using a hybrid, virtual reality-assisted teaching program showed no superiority to novices trained using a conventional teaching program, but with less burden on teaching resources.

Biexponential diffusion decay in formalin-fixed prostate tissue: preliminary findings.

Magnetic resonance microimaging was used to measure diffusion decay over an extended b-factor range in a formalin-fixed normal prostate sample and a Gleason pattern 3+4 cancer tissue sample. The coefficients of biexponential fits to diffusion decay data from 1600 voxels of dimension 160 × 160 × 160 µm(3) in each sample were correlated with underlying epithelial and stromal compartment partial volumes estimated from high-resolution apparent diffusion coefficient (ADC) data (40 × 40 × 40 µm(3) voxels) from the same tissue. In the normal tissue sample, the signal fractions of the low and high ADC components of the biexponential fits correlated linearly with partial volumes of epithelial tissue (R(2) = 0.6) and stromal tissue (R(2) = 0.5), respectively. Similar but weaker correlations were observed in the cancer sample. Epithelium-containing high spatial resolution voxels appeared to be composed of ∼60% low ADC and ∼40% high ADC component. Stromal voxels appeared to be composed of ∼20% low ADC and ∼80% high ADC component. This preliminary report suggests that distinctly different diffusion properties in microscopically adjacent cell types contribute to the multiexponential diffusion decay phenomenon in prostate tissue.