2D-3D Reconstruction-Based Planning of Total Hip Arthroplasty

This chapter proposed a personalized X-ray reconstruction-based planning and post-operative treatment evaluation framework called iJoint for advancing modern Total Hip Arthroplasty (THA). Based on a mobile X-ray image calibration phantom and a unique 2D-3D reconstruction technique, iJoint can generate patient-specific models of hip joint by non-rigidly matching statistical shape models to the X-ray radiographs. Such a reconstruction enables a true 3D planning and treatment evaluation of hip arthroplasty from just 2D X-ray radiographs whose acquisition is part of the standard diagnostic and treatment loop. As part of the system, a 3D model-based planning environment provides surgeons with hip arthroplasty related parameters such as implant type, size, position, offset and leg length equalization. With this newly developed system, we are able to provide true 3D solutions for computer assisted planning of THA using only 2D X-ray radiographs, which is not only innovative but also cost-effective.

Reference values of mechanical and thermal pain tests in a pain-free population

Quantitative sensory tests are widely used in human research to evaluate the effect of analgesics and explore altered pain mechanisms, such as central sensitization. In order to apply these tests in clinical practice, knowledge of reference values is essential. The aim of this study was to determine the reference values of pain thresholds for mechanical and thermal stimuli, as well as withdrawal time for the cold pressor test in 300 pain-free subjects. Pain detection and pain tolerance thresholds to pressure, heat and cold were determined at three body sites: (1) lower back, (2) suprascapular region and (3) second toe (for pressure) or the lateral aspect of the leg (for heat and cold). The influences of gender, age, height, weight, body-mass index (BMI), body side of testing, depression, anxiety, catastrophizing and parameters of Short-Form 36 (SF-36) were analyzed by multiple regressions. Quantile regressions were performed to define the 5th, 10th and 25th percentiles as reference values for pain hypersensitivity and the 75th, 90th and 95th percentiles as reference values for pain hyposensitivity. Gender, age and/or the interaction of age with gender were the only variables that consistently affected the pain measures. Women were more pain sensitive than men. However, the influence of gender decreased with increasing age. In conclusion, normative values of parameters related to pressure, heat and cold pain stimuli were determined. Reference values have to be stratified by body region, gender and age. The determination of these reference values will now allow the clinical application of the tests for detecting abnormal pain reactions in individual patients.

The examination and identification of bite marks in foods using 3D scanning and 3D comparison methods

Bite mark analysis offers the opportunity to identify the biter based on the individual characteristics of the dentitions. Normally, the main focus is on analysing bite mark injuries on human bodies, but also, bite marks in food may play an important role in the forensic investigation of a crime. This study presents a comparison of simulated bite marks in different kinds of food with the dentitions of the presumed biter. Bite marks were produced by six adults in slices of buttered bread, apples, different kinds of Swiss chocolate and Swiss cheese. The time-lapse influence of the bite mark in food, under room temperature conditions, was also examined. For the documentation of the bite marks and the dentitions of the biters, 3D optical surface scanning technology was used. The comparison was performed using two different software packages: the ATOS modelling and analysing software and the 3D studio max animation software. The ATOS software enables an automatic computation of the deviation between the two meshes. In the present study, the bite marks and the dentitions were compared, as well as the meshes of each bite mark which were recorded in the different stages of time lapse. In the 3D studio max software, the act of biting was animated to compare the dentitions with the bite mark. The examined food recorded the individual characteristics of the dentitions very well. In all cases, the biter could be identified, and the dentitions of the other presumed biters could be excluded. The influence of the time lapse on the food depends on the kind of food and is shown on the diagrams. However, the identification of the biter could still be performed after a period of time, based on the recorded individual characteristics of the dentitions.

High accuracy alignment facility for the receiver and transmitter of the BepiColombo Laser Altimeter

The accurate co-alignment of the transmitter to the receiver of the BepiColombo Laser Altimeter is a challenging task for which an original alignment concept had to be developed. We present here the design, construction and testing of a large collimator facility built to fulfill the tight alignment requirements. We describe in detail the solution found to attenuate the high energy of the instrument laser transmitter by an original beam splitting pentaprism group. We list the different steps of the calibration of the alignment facility and estimate the errors made at each of these steps. We finally prove that the current facility is ready for the alignment of the flight instrument. Its angular accuracy is 23 μrad.

3D documentation of footwear impressions and tyre tracks in snow with high resolution optical surface scanning

The three-dimensional documentation of footwear and tyre impressions in snow offers an opportunity to capture additional fine detail for the identification as present photographs. For this approach, up to now, different casting methods have been used. Casting of footwear impressions in snow has always been a difficult assignment. This work demonstrates that for the three-dimensional documentation of impressions in snow the non-destructive method of 3D optical surface scanning is suitable. The new method delivers more detailed results of higher accuracy than the conventional casting techniques. The results of this easy to use and mobile 3D optical surface scanner were very satisfactory in different meteorological and snow conditions. The method is also suitable for impressions in soil, sand or other materials. In addition to the side by side comparison, the automatic comparison of the 3D models and the computation of deviations and accuracy of the data simplify the examination and delivers objective and secure results. The results can be visualized efficiently. Data exchange between investigating authorities at a national or an international level can be achieved easily with electronic data carriers.

Application of 3D documentation and geometric reconstruction methods in traffic accident analysis: with high resolution surface scanning, radiological MSCT/MRI scanning and real data based animation

The examination of traffic accidents is daily routine in forensic medicine. An important question in the analysis of the victims of traffic accidents, for example in collisions between motor vehicles and pedestrians or cyclists, is the situation of the impact. Apart from forensic medical examinations (external examination and autopsy), three-dimensional technologies and methods are gaining importance in forensic investigations. Besides the post-mortem multi-slice computed tomography (MSCT) and magnetic resonance imaging (MRI) for the documentation and analysis of internal findings, highly precise 3D surface scanning is employed for the documentation of the external body findings and of injury-inflicting instruments. The correlation of injuries of the body to the injury-inflicting object and the accident mechanism are of great importance. The applied methods include documentation of the external and internal body and the involved vehicles and inflicting tools as well as the analysis of the acquired data. The body surface and the accident vehicles with their damages were digitized by 3D surface scanning. For the internal findings of the body, post-mortem MSCT and MRI were used. The analysis included the processing of the obtained data to 3D models, determination of the driving direction of the vehicle, correlation of injuries to the vehicle damages, geometric determination of the impact situation and evaluation of further findings of the accident. In the following article, the benefits of the 3D documentation and computer-assisted, drawn-to-scale 3D comparisons of the relevant injuries with the damages to the vehicle in the analysis of the course of accidents, especially with regard to the impact situation, are shown on two examined cases.

Noninvasive determination of intraocular pressure (IOP) in nonsedated mice of 5 different inbred strains

BACKGROUND: Noninvasive intraocular pressure (IOP) measurement in mice is critically important for understanding the pathophysiology of glaucoma. Rebound tonometry is one of the methods that can be used for obtaining such measurements. We evaluated the ability of the rebound tonometer (RT) to determine IOP differences among various mouse strains and whether differences in corneal thickness may affect IOP measurements in these animals. MATERIALS AND METHODS: Five different commonly used mouse strains (BALB/C, CBA/CAHN, AKR/J, CBA/J, and 129P3/J) were used. IOP was measured in eyes from 12 nonsedated animals (6 male and 6 female) from each strain at 2 to 3 months of age using the RT. IOPs were measured in all animals, on 2 different days between 10 AM and 12 PM. Subsequently, a number of eyes from each strain were cannulated to provide a calibration curve specific for that strain. Tonometer readings for all strains were converted to apparent IOP values using the calibration data obtained from the calibration curve of the respective strain. For comparison purposes, IOP values were also obtained using the C57BL/6 calibration data previously reported. IOP for the 5 strains, male and female animals, and the different occasion of measurement were compared using repeat measures analysis of variance. The central corneal thickness (CCT) of another group of 8 male animals from each of the 5 strains was also measured using an optical low coherence reflectometry (OLCR) pachymeter modified for use with mice. CCT values were correlated to mean IOPs of male animals and to the slopes and intercept of individual strain calibration curves. RESULTS: Noninvasive IOP measurements confirm that the BALB/C strain has lower and the CBA/CAHN has higher relative IOPs than other mouse strains while the AKR/J, the CBA/J, and the 129P3/J strains have intermediate IOPs. There is a very good correlation of apparent IOP values obtained by RT with previously reported true IOPs obtained by cannulation. There was a small but statistically significant difference in IOP between male and female animals in 2 strains (129P3/J and AKR/J) with female mice having higher relative IOPs. No correlation between CCT and IOP was detected. CCT did not correlate with any of the constants describing the calibration curves in the various strains. CONCLUSIONS: Noninvasive IOP measurement in mice using the RT can be used to help elucidate IOP phenotype, after prior calibration of the tonometer. CCT has no effect on mouse IOP measurements using the RT.

Development of the premature infant nose throat-model (PrINT-Model): an upper airway replica of a premature neonate for the study of aerosol delivery

Clinical efficacy of aerosol therapy in premature newborns depends on the efficiency of delivery of aerosolized drug to the bronchial tree. To study the influence of various anatomical, physical, and physiological factors on aerosol delivery in preterm newborns, it is crucial to have appropriate in vitro models, which are currently not available. We therefore constructed the premature infant nose throat-model (PrINT-Model), an upper airway model corresponding to a premature infant of 32-wk gestational age by three-dimensional (3D) reconstruction of a three-planar magnetic resonance imaging scan and subsequent 3D-printing. Validation was realized by visual comparison and comparison of total airway volume. To study the feasibility of measuring aerosol deposition, budesonide was aerosolized through the cast and lung dose was expressed as percentage of nominal dose. The airway volumes of the initial magnetic resonance imaging and validation computed tomography scan showed a relative deviation of 0.94%. Lung dose at low flow (1 L/min) was 61.84% and 9.00% at high flow (10 L/min), p < 0.0001. 3D-reconstruction provided an anatomically accurate surrogate of the upper airways of a 32-wk-old premature infant, making the model suitable for future in vitro testing.

Early loading of nonsubmerged titanium implants with a chemically modified sand-blasted and acid-etched surface: 6-month results of a prospective case series study in the posterior mandible focusing on peri-implant crestal bone changes and implant stability quotient (ISQ) values

PURPOSE: The aim of this prospective case series study was to evaluate the short-term success rates of titanium screw-type implants with a chemically modified sand-blasted and acid-etched (mod SLA) surface after 3 weeks of healing. MATERIAL AND METHODS: A total of 56 implants were inserted in the posterior mandible of 40 partially edentulous patients exhibiting bone densities of class I to III. After a healing period of 3 weeks, all implants were functionally loaded with a screw-retained crown or fixed dental prosthesis. The patients were recalled at weeks 4, 7, 12, and 26 for monitoring and assessment of clinical and radiological parameters, including implant stability quotient (ISQ) measurements. RESULTS: None of the implants failed to integrate. However, two implants were considered "spinners" at day 21 and left unloaded for an extended period. Therefore, 96.4% of the inserted implants were loaded according to the protocol tested. All 56 implants including the "spinners" showed favorable clinical and radiographic findings at the 6-month follow-up examination. The ISQ values increased steadily throughout the follow-up period. At the time of implant placement, the range of ISQ values exhibited a mean of 74.33, and by week 26, a mean value of 83.82 was recorded. Based on strict criteria, all 56 implants were considered successfully integrated, resulting in a 6-month survival and success rate of 100.0%. CONCLUSION: This prospective study using an early-loading protocol after 3 weeks of healing demonstrated that titanium implants with the modified SLA surface can achieve and maintain successful tissue integration over a period of at least 6 months. The ISQ method seems feasible to monitor implant stability during the initial wound-healing period.

The identification of cerebral volume changes in treated growth hormone-deficient adults using serial 3D MR image processing

A pilot study to detect volume changes of cerebral structures in growth hormone (GH)-deficient adults treated with GH using serial 3D MR image processing and to assess need for segmentation prior to registration was conducted.

Comparison of arterial blood pressure measurements and hypertension scores obtained by use of three indirect measurement devices in hospitalized dogs

OBJECTIVE: To evaluate the agreement of blood pressure measurements and hypertension scores obtained by use of 3 indirect arterial blood pressure measurement devices in hospitalized dogs. Design-Diagnostic test evaluation. ANIMALS: 29 client-owned dogs. PROCEDURES: 5 to 7 consecutive blood pressure readings were obtained from each dog on each of 3 occasions with a Doppler ultrasonic flow detector, a standard oscillometric device (STO), and a high-definition oscillometric device (HDO). RESULTS: When the individual sets of 5 to 7 readings were evaluated, the coefficient of variation for systolic arterial blood pressure (SAP) exceeded 20% for 0% (Doppler), 11 % (STO), and 28% (HDO) of the sets of readings. After readings that exceeded a 20% coefficient of variation were discarded, repeatability was within 25 (Doppler), 37 (STO), and 39 (HDO) mm Hg for SAP. Correlation of mean values among the devices was between 0.47 and 0.63. Compared with Doppler readings, STO underestimated and HDO overestimated SAP. Limits of agreement between mean readings of any 2 devices were wide. With the hypertension scale used to score SAP, the intraclass correlation of scores was 0.48. Linear-weighted inter-rater reliability between scores was 0.40 (Doppler vs STO), 0.38 (Doppler vs HDO), and 0.29 (STO vs HDO). CONCLUSIONS AND CLINICAL RELEVANCE: Results of this study suggested that no meaningful clinical comparison can be made between blood pressure readings obtained from the same dog with different indirect blood pressure measurement devices.

Circadian blood pressure during the early course of type 1 diabetes. Analysis of 1,011 ambulatory blood pressure recordings in 354 adolescents and young adults

OBJECTIVE Little information is available on the early course of hypertension in type 1 diabetes. The aim of our study, therefore, was to document circadian blood pressure profiles in patients with a diabetes duration of up to 20 years and relate daytime and nighttime blood pressure to duration of diabetes, BMI, insulin therapy, and HbA1c. RESEARCH DESIGN AND METHODS Ambulatory profiles of 24-h blood pressure were recorded in 354 pediatric patients with type 1 diabetes (age 14.6 +/- 4.2 years, duration of diabetes 5.6 +/- 5.0 years, follow-up for up to 9 years). A total of 1,011 profiles were available for analysis from patients not receiving antihypertensive medication. RESULTS Although daytime mean systolic pressure was significantly elevated in diabetic subjects (+3.1 mmHg; P < 0.0001), daytime diastolic pressure was not different from from the height- and sex-adjusted normal range (+0.1 mmHg, NS). In contrast, both systolic and diastolic nighttime values were clearly elevated (+7.2 and +4.2 mmHg; P < 0.0001), and nocturnal dipping was reduced (P < 0.0001). Systolic blood pressure was related to overweight in all patients, while diastolic blood pressure was related to metabolic control in young adults. Blood pressure variability was significantly lower in girls compared with boys (P < 0.01). During follow-up, no increase of blood pressure was noted; however, diastolic nocturnal dipping decreased significantly (P < 0.03). Mean daytime blood pressure was significantly related to office blood pressure (r = +0.54 for systolic and r = +0.40 for diastolic pressure); however, hypertension was confirmed by ambulatory blood pressure measurement in only 32% of patients with elevated office blood pressure. CONCLUSIONS During the early course of type 1 diabetes, daytime blood pressure is higher compared with that of healthy control subjects. The elevation of nocturnal values is even more pronounced and nocturnal dipping is reduced. The frequency of white-coat hypertension is high among adolescents with diabetes, and ambulatory blood pressure monitoring avoids unnecessary antihypertensive treatment.

A new methodological protocol for the use of dendrogeomorphological data in flood risk analysis

Dendrogeomorphology uses information sources recorded in the roots, trunks and branches of trees and bushes located in the fluvial system to complement (or sometimes even replace) systematic and palaeohydrological records of past floods. The application of dendrogeomorphic data sources and methods to palaeoflood analysis over nearly 40 years has allowed improvements to be made in frequency and magnitude estimations of past floods. Nevertheless, research carried out so far has shown that the dendrogeomorphic indicators traditionally used (mainly scar evidence), and their use to infer frequency and magnitude, have been restricted to a small, limited set of applications. New possibilities with enormous potential remain unexplored. New insights in future research of palaeoflood frequency and magnitude using dendrogeomorphic data sources should: (1) test the application of isotopic indicators (16O/18O ratio) to discover the meteorological origin of past floods; (2) use different dendrogeomorphic indicators to estimate peak flows with 2D (and 3D) hydraulic models and study how they relate to other palaeostage indicators; (3) investigate improved calibration of 2D hydraulic model parameters (roughness); and (4) apply statistics-based cost–benefit analysis to select optimal mitigation measures. This paper presents an overview of these innovative methodologies, with a focus on their capabilities and limitations in the reconstruction of recent floods and palaeofloods.