The airflow perturbation device (APD) has been developed as a portable, easy to use, and a rapid response instrument for measuring respiratory resistance in humans. However, the APD has limited data validating it against the established techniques. This study used a mechanical system to simulate the normal range of human breathing to validate the APD with the clinically accepted impulse oscillometry (IOS) technique. The validation system consisted of a sinusoidal flow generator with ten standardized resistance configurations that were shown to represent a total range of resistances from 0.12 to 0.95&#x2009;kPa&#xb7;L&#x2212;1&#xb7;s (1.2&#x2013;9.7&#x2009;cm H2O&#xb7;L&#x2212;1&#xb7;s). Impulse oscillometry measurements and APD measurements of the mechanical system were recorded and compared at a constant airflow of 0.15&#x2009;L&#xb7;s&#x2212;1. Both the IOS and APD measurments were accurate in assessing nominal resistance. In addition, a strong linear relationship was observed between APD measurements and IOS measurements (R2&#x2009;=&#x2009;0.999). A second series of measurements was made on ten human volunteers with external resistors added in their respiratory flow paths. Once calibrated with the mechanical system, the APD gave respiratory resistance measurements within 5&#x25; of IOS measurements. Because of their comparability to IOS measurements, APD measurements are shown to be valid representations of respiratory resistance.

J. Pan

A. Saltos

D. Smith

A. Johnson

J. Vossoughi

Comparison of Respiratory Resistance Measurements Made with an Airflow Perturbation Device with Those from Impulse Oscillometry

Electrical impedance tomography (EIT) has the potential to provide a low cost and safe imaging modality for clinically monitoring patients being treated with mechanical ventilation. Variations in reconstruction algorithms at different clinical settings, however,  make interpretation of regional ventilation across institutions difficult, presenting the need for a unified algorithm
for thoracic EIT reconstruction. Development of such a consensual reconstruction algorithm necessitates a forward model capable of predicting surface impedance measurements as well 
as electric fields in the interior of the modeled thoracic volume. In this paper, we present  an anatomically realistic forward solver for thoracic EIT that was built based on high resolution MR image data of a representative adult. Accuracy assessment of the developed forward solver in predicting surface impedance measurements by comparing the predicted and observed impedance measurements shows that the relative error is within the order of 5&#x25;, demonstrating the ability of the presented forward solver in generating high-fidelity surface thoracic impedance data for thoracic EIT algorithm development and evaluation.

Fei Yang

Jie Zhang

Robert Patterson

Development of an Anatomically Realistic Forward Solver for Thoracic Electrical Impedance Tomography

A novel control methodology which uses a low-resolution encoder is presented for a cellular microinjection technology called the Ros-Drill (rotationally oscillating drill). It is developed primarily for ICSI (intracytoplasmic sperm injection) operations, with the objective of generating a desired oscillatory motion at the tip of a micro glass pipette. It is an inexpensive setup, which creates high-frequency (higher than 500&#x2009;Hz) and small-amplitude (around 0.2 deg) rotational oscillations at the tip of an injection pipette. These rotational oscillations enable the pipette to drill into cell membranes with minimum biological damage. Such a motion control procedure presents no particular difficulty when it uses sufficiently precise motion sensors. However, size, costs, and accessibility of technology to the hardware components severely constrain the sensory capabilities. Consequently, the control mission and the trajectory tracking are adversely affected. This paper presents two contributions: (a) a dedicated novel adaptive feedback control method to achieve a satisfactory trajectory tracking capability. We demonstrate via experiments that the tracking of the harmonic rotational motion is achieved with desirable fidelity; (b) some important analytical features and related observations associated with the controlled harmonic motion which is created by the low-resolution feedback control structure.

Zhenyu Zhang

Nejat Olgac

An Adaptive Control Method for Ros-Drill Cellular Microinjector with Low-Resolution Encoder

CT and digital subtraction angiography (DSA) are ubiquitous in the clinic. Their preclinical equivalents are valuable imaging methods for studying disease models and treatment. We have developed a dual source/detector X-ray imaging system that we have used for both micro-CT and DSA studies in rodents. The control of such a complex imaging system requires substantial software development for which we use the graphical language LabVIEW (National Instruments, Austin, TX, USA). This paper focuses on a LabVIEW platform that we have developed to enable anatomical and functional imaging with micro-CT and DSA. Our LabVIEW applications integrate and control all the elements of our system including a dual source/detector X-ray system, a mechanical ventilator, a physiological monitor, and a power microinjector for the vascular delivery of X-ray contrast agents. Various applications allow cardiac- and respiratory-gated acquisitions for both DSA and micro-CT studies. Our results illustrate the application of DSA for cardiopulmonary studies and vascular imaging of the liver and coronary arteries. We also show how DSA can be used for functional imaging of the kidney. Finally, the power of 4D micro-CT imaging using both prospective and retrospective gating is shown for cardiac imaging.

Cristian T. Badea

Laurence W. Hedlund

G. Allan Johnson

A LabVIEW Platform for Preclinical Imaging Using Digital Subtraction Angiography and Micro-CT

An MR acquisition protocol and a processing method using distributed computing on the European Grid Infrastructure (EGI) to allow 3D liver perfusion parametric mapping after Magnetic Resonance Dynamic Contrast Enhanced (MR-DCE) imaging are presented. Seven patients (one healthy control and six with chronic liver diseases) were prospectively enrolled after liver biopsy. MR-dynamic acquisition was continuously performed in free-breathing during two minutes after simultaneous intravascular contrast agent (MS-325 blood pool agent) injection. Hepatic capillary system was modeled by a 3-parameters one-compartment pharmacokinetic model. The processing step was parallelized and executed on the EGI. It was modeled and implemented as a grid workflow using the Gwendia language and the MOTEUR workflow engine. Results showed good reproducibility in repeated processing on the grid. The results obtained from the grid were well correlated with ROI-based reference method ran locally on a personal computer. The speed-up range was 71 to 242 with an average value of 126. In conclusion, distributed computing applied to perfusion mapping brings significant speed-up to quantification step to be used for further clinical studies in a research context. Accuracy would be improved with higher image SNR accessible on the latest 3T MR systems available today.

Benjamin Leporq

Sorina Camarasu-Pop

Eduardo E. Davila-Serrano

Frank Pilleul

Olivier Beuf

Enabling 3D-Liver Perfusion Mapping from MR-DCE Imaging Using Distributed Computing

Stromal vascular fraction (SVF) combined with platelet-rich plasma (PRP) is commonly used in preclinical and clinical osteoarthritis as well as articular cartilage injury treatment. However, this therapy has not carefully evaluated the safety and the efficacy. This research aims to assess the safety and the efficacy of SVF combined with PRP transplantation. Ten samples of SVFs and PRPs from donors were used in this research. About safety, we evaluate the expression of some genes related to tumor formation such as Oct-4, Nanog, SSEA3, and SSEA4 by RT-PCR, flow cytometry, and tumor formation when injected in NOD/SCID mice. About efficacy, SVF was injected with PRP into murine joint that caused joint failure. The results showed that SVFs are negative with Oct-4, Nanog, SSEA-3, and SSEA-4, as well as they cannot cause tumors in mice. SVFs combined with PRP can improve the joint regeneration in mice. These results proved that SVFs combined with PRP transplantation is a promising therapy for articular cartilage injury treatment.

Phuc Van Pham

Khanh Hong-Thien Bui

Dat Quoc Ngo

Lam Tan Khuat

Ngoc Kim Phan

Transplantation of Nonexpanded Adipose Stromal Vascular Fraction and Platelet-Rich Plasma for Articular Cartilage Injury Treatment in Mice Model

The purpose of this study was to investigate the contribution of individual muscles (MJRSm) to total joint rotational stiffness (MJRST) about the lumbar spine's <svg style="vertical-align:-3.3907pt;width:25.549999px;" id="M2" height="15.4" version="1.1" viewBox="0 0 25.549999 15.4" width="25.549999" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg">
	
		
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</svg> joint prior to, and following, sudden dynamic flexion or extension perturbations to the trunk. We collected kinematic and surface electromyography (sEMG) data while subjects maintained a kneeling posture on a parallel robotic platform, with their pelvis constrained by a harness. The parallel robotic platform caused sudden inertial trunk flexion or extension perturbations, with and without the subjects being aware of the timing and direction. Prevoluntary muscle forces incorporating both short and medium latency neuromuscular responses contributed significantly to joint rotational stiffness, following both sudden trunk flexion and extension motions. MJRST did not change with perturbation direction awareness. The lumbar erector spinae were always the greatest contributor to MJRST. This indicates that the neuromuscular feedback system significantly contributed to MJRST, and this behaviour likely enhances joint stability following sudden trunk flexion and extension perturbations.

Joel A. Cort

James P. Dickey

Jim R. Potvin

Muscle Contributions to <svg style="vertical-align:-3.39069pt" height="15.4" version="1.1" viewBox="0 0 25.549999 15.4" width="25.549999" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"><g transform="matrix(.017,-0,0,-.017,.062,11.112)"><path id="x4C" d="M495 163l30 -6q-19 -99 -36 -157h-453v28q63 5 77.5 20t14.5 78v400q0 63 -13 77t-75 19v28h261v-28q-61 -5 -74.5 -19t-13.5 -77v-395q0 -41 5 -59t18 -25q24 -13 96 -13q85 0 112 31q30 33 51 98z"/></g><g transform="matrix(.012,-0,0,-.012,9.213,15.187)"><path id="x34" d="M456 178h-96v-72q0 -51 12.5 -62.5t72.5 -16.5v-27h-256v27q65 5 78 17t13 62v72h-260v28q182 271 300 426h40v-407h96v-47zM280 225v295h-2q-107 -148 -196 -295h198z"/></g><g transform="matrix(.012,-0,0,-.012,14.924,15.187)"><path id="x2D" d="M300 253l-14 -55h-229l14 55h229z"/></g><g transform="matrix(.012,-0,0,-.012,19.16,15.187)"><path id="x35" d="M153 550l-26 -186q79 31 111 31q90 0 141.5 -51t51.5 -119q0 -93 -89 -166q-85 -69 -173 -71q-32 0 -61.5 11.5t-41.5 23.5q-18 17 -17 34q2 16 22 33q14 9 26 -1q61 -50 124 -50q60 0 93 43.5t33 104.5q0 69 -41.5 110t-121.5 41q-53 0 -102 -20l38 305h286l6 -8
l-26 -65h-233z"/></g></svg> Joint Rotational Stiffness following Sudden Trunk Flexion and Extension Perturbations

Background. A caries lesion causes changes in the optical properties of the affected tissue. Currently a caries lesion can be detected only at a relatively late stage of development. Caries diagnosis also suffers from high interobserver variance. Methods. This is a pilot study to test the suitability of an optical diffuse reflectance spectroscopy for caries diagnosis. Reflectance visible/near-infrared spectroscopy (VIS/NIRS) was used to measure caries lesions and healthy enamel on extracted human teeth. The results were analysed with a computational algorithm in order to find a rule-based classification method to detect caries lesions. Results. The classification indicated that the measured points of enamel could be assigned to one of three classes: healthy enamel, a caries lesion, and stained healthy enamel. The features that enabled this were consistent with theory. Conclusions. It seems that spectroscopic measurements can help to reduce false positives at in vitro setting. However, further research is required to evaluate the strength of the evidence for the method&#x2019;s performance.

Mika Ruohonen

Katri Palo

Jarmo Alander

Spectroscopic Detection of Caries Lesions

Telemonitoring during the golden hour of patient transportation helps to improve medical care. Presently there are different physiological data acquisition and transmission systems using cellular network and radio communication links. Location monitoring systems and video transmission systems are also commercially available. The emergency patient transportation systems uniquely require transmission of data pertaining to the patient, vehicle, time of the call, physiological signals (like ECG, blood pressure, a body temperature,  and blood oxygen saturation), location information, a snap shot of the patient, and voice. These requirements are presently met by using separate communication systems for voice, physiological data, and location that result in a lot of inconvenience to the technicians, maintenance related issues, in addition to being expensive. This paper presents design, development, and implementation of such a telemonitoring system for emergency patient transportation employing ARM 9 processor module. This system is found to be very useful for the emergency patient transportation being undertaken by organizations like the Emergency Management Research Institute (EMRI).

K. Satyanarayana

A. D. Sarma

J. Sravan

M. Malini

G. Venkateswarlu

GPS and GPRS Based Telemonitoring System for Emergency Patient Transportation

Micromotion of dental implants may interfere with the process of osseointegration. Using three different types of virtual biomechanical models, varying contact types between implant and bone were simulated, and implant deformation, bone deformation, and stress at the implant-bone interface were recorded under an axial load of 200&#x2009;N, which reflects a common biting force. Without friction between implant and bone, a symmetric loading situation of the bone with maximum loading and displacement at the apex of the implant was recorded. The addition of threads led to a decrease in loading and displacement at the apical part, but loading and displacement were also observed at the vertical walls of the implants. Introducing friction between implant and bone decreased global displacement. In a force fit situation, load transfer predominantly occurred in the cervical area of the implant. For freshly inserted implants, micromotion was constant along the vertical walls of the implant, whereas, for osseointegrated implants, the distribution of micromotion depended on the location. In the cervical aspect some minor micromotion in the range of 0.75&#x2009;&#x3bc;m could be found, while at the most apical part almost no relative displacement between implant and bone occurred.

Werner Winter

Daniel Klein

Matthias Karl

Micromotion of Dental Implants: Basic Mechanical Considerations

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Journal of Medical Engineering