Real-time visualisation and analysis of internal examinations--seeing the unseen

Taking the Pressure Off the Patient - Understanding Digital Rectal Examinations on a Real Subject

Better understanding of palpation techniques during unsighted physical examinations has mostly been limited to qualitative and quantitative studies of performance of experts whilst conducting examinations on plastic benchtop models. However, little is known about their performance when conducting such examinations on real subjects.

OBJECTIVE

The aim of this paper is to better understand palpation techniques of experts whilst conducting a Digital Rectal Examination on a real subject.

METHODS

We recruited four consultants from relevant specialties and asked them to conduct two DREs on a Rectal Teaching Assistant whilst wearing small position and pressure sensors on their examining finger. We segmented the relevant anatomy from an MRI taken of the pelvic region, registered 3D models and analysed retrospectively performance in relation to executed tasks, supination/pronation, palpation convex hull and pressure applied.

RESULTS

Primary care consultants examined the anatomy more holistically compared to secondary care experts, the maximum pressure applied across experiments is 3.3N, overall the pressure applied on the prostate is higher than that applied to rectal walls, and the urologist participant not only applied the highest pressure but also did so with the highest most prominent frequency (15.4 and 25.3 Hz).

CONCLUSIONS

The results of our research allow for better understanding of experts' technical performance from relevant specialities when conducting a DRE, and suggest the range of pressure applied whilst palpating anatomy.

SIGNIFICANCE

This research will be valuable in improving the design of haptics-based learning tools, as well as in encouraging reflection on palpation styles across different specialities to develop metrics of performance.

Real-time Visualisation and Analysis of Clinicians' Performance during Palpation in Physical Examinations

OBJECTIVE

Motivated by the fact that palpation skills are challenging to learn and teach, particularly during Digital Rectal Examinations (DRE), and the lack of understanding of what constitutes adequate performance, we present a visualisation and analysis system that uses small position and pressure sensors located on the examining finger, allowing the quantitative analysis of duration, steps and pressure applied.

METHODS

The system is first described, followed by an experimental study of twenty experts from four clinical specialties performing ten DREs each on a benchtop model using the proposed system. Analysis of the constitutive steps was conducted to improve understanding of the examination. A Markov model representing executed tasks and analysis of pressure applied is also introduced.

RESULTS

The proposed system successfully allowed the visualisation and analysis during the experimental study. General Practitioners and Nurses were found to execute more tasks compared to Urologists and Colorectal Surgeons. Urologists executed the least number of tasks and were the most consistent group compared to others.

CONCLUSION

The ability to "see through" allowed us to better characterise the performance of experts when conducting a DRE on a benchtop model, comparing the performance of relevant specialties, and studying executed tasks and the pressure applied. The Markov model presented summarises task execution of experts and could be used to compare performance of novices against that of experts.

SIGNIFICANCE

This approach allows for the analysis of performance based on continuous sensor data recording that can be easily extended to real subjects and other types of physical examinations.

Programmable prostate palpation simulator using property-changing pneumatic bladder

The currently available prostate palpation simulators are based on either a physical mock-up or pure virtual simulation. Both cases have their inherent limitations. The former lacks flexibility in presenting abnormalities and scenarios because of the static nature of the mock-up and has usability issues because the prostate model must be replaced in different scenarios. The latter has realism issues, particularly in haptic feedback, because of the very limited performance of haptic hardware and inaccurate haptic simulation. This paper presents a highly flexible and programmable simulator with high haptic fidelity. Our new approach is based on a pneumatic-driven, property-changing, silicone prostate mock-up that can be embedded in a human torso mannequin. The mock-up has seven pneumatically controlled, multi-layered bladder cells to mimic the stiffness, size, and location changes of nodules in the prostate. The size is controlled by inflating the bladder with positive pressure in the chamber, and a hard nodule can be generated using the particle jamming technique; the fine sand in the bladder becomes stiff when it is vacuumed. The programmable valves and system identification process enable us to precisely control the size and stiffness, which results in a simulator that can realistically generate many different diseases without replacing anything. The three most common abnormalities in a prostate are selected for demonstration, and multiple progressive stages of each abnormality are carefully designed based on medical data. A human perception experiment is performed by actual medical professionals and confirms that our simulator exhibits higher realism and usability than do the conventional simulators.