Video-rate optical flow corrected intraoperative functional fluorescence imaging.

Intraoperative fluorescence molecular imaging based on targeted fluorescence agents is an emerging approach to improve surgical and endoscopic imaging and guidance. Short exposure times per frame and implementation at video rates are necessary to provide continuous feedback to the physician and avoid motion artifacts. However, fast imaging implementations also limit the sensitivity of fluorescence detection.

Multispectral optoacoustic tomography by means of normalized spectral ratio.

Quantification of biomarkers using multispectral optoacoustic tomography can be challenging due to photon fluence variations with depth and spatially heterogeneous tissue optical properties. Herein we introduce a spectral ratio approach that accounts for photon fluence variations. The performance and imaging improvement achieved with the proposed method is showcased both numerically and experimentally in phantoms and mice.

Reconstruction of fluorescence distribution hidden in biological tissue using mesoscopic epifluorescence tomography.

Mesoscopic epifluorescence tomography is a novel technique that discovers fluorescence bio-distribution in small animals by tomographic means in reflectance geometry. A collimated laser beam is scanned over the skin surface to excite fluorophores hidden within the tissue while a CCD camera acquires an image of the fluorescence emission for each source position. This configuration is highly efficient in the visible spectrum range where trans-illumination imaging of small animals is not feasible due to the high tissue absorption and scattering in biological organisms.

Optoacoustic tomography with varying illumination and non-uniform detection patterns.

Quantification of tissue morphology and biomarker distribution by means of optoacoustic tomography is an important and longstanding challenge, mainly caused by the complex heterogeneous structure of biological tissues as well as the lack of accurate and robust reconstruction algorithms. The recently introduced model-based inversion approaches were shown to mitigate some of reconstruction artifacts associated with the commonly used back-projection schemes, while providing an excellent platform for obtaining quantified maps of optical energy deposition in experimental configurations of various complexity. In this work, we introduce a weighted model-based approach, capable of overcoming reconstruction challenges caused by per-projection variations of object's illumination and other partial illumination effects.

Fast automatic segmentation of anatomical structures in x-ray computed tomography images to improve fluorescence molecular tomography reconstruction.

The recent development of hybrid imaging scanners that integrate fluorescence molecular tomography (FMT) and x-ray computed tomography (XCT) allows the utilization of x-ray information as image priors for improving optical tomography reconstruction. To fully capitalize on this capacity, we consider a framework for the automatic and fast detection of different anatomic structures in murine XCT images. To accurately differentiate between different structures such as bone, lung, and heart, a combination of image processing steps including thresholding, seed growing, and signal detection are found to offer optimal segmentation performance.

Functional malcentering of the humeral head and asymmetric long-term stress on the glenoid: potential reasons for glenoid loosening in total shoulder arthroplasty.

We tested the hypothesis that functional malcentering of the humeral head during arm elevation exists in patients with glenohumeral osteoarthritis and influences long-term glenoid loading. Twenty-eight healthy volunteers and 10 patients with primary osteoarthritis, 10 with cuff-arthropathy, and 1 with dysplastic glenoid were examined. Open magnetic resonance imaging and 3-dimensional (3D) digital postprocessing techniques were applied in various arm positions.

Multimodal virtual bronchoscopy using PET/CT images.

Objective: To demonstrate the possibilities, advantages and limitations of virtual bronchoscopy using data sets from positron emission tomography (PET) and computed tomography (CT).

Materials And Methods: Eight consecutive patients with non-small cell lung cancer (NSCLC) underwent PET/CT. PET was performed with a glucose analog, 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (18F-FDG), using a state-of-the-art full-ring Pico-3D PET scanner.

Virtual positron emission tomography/computed tomography-bronchoscopy: possibilities, advantages and limitations of clinical application.

The aim of this study was to demonstrate the possibilities, advantages and limitations of virtual bronchoscopy using data sets from positron emission tomography (PET) and computed tomography (CT). Twelve consecutive patients with lung cancer underwent PET/CT. PET was performed with F-18-labelled 2-[fluorine-18]-fluoro-2-deoxy-D: -glucose ((18)F-FDG).

Systematic, standardized and comprehensive neurological phenotyping of inbred mice strains in the German Mouse Clinic.

Neurological and psychiatric disorders are among the most common and most serious health problems in developed countries. Transgenic mouse models mimicking human neurological diseases have provided new insights into development and function of the nervous system. One of the prominent goals of the German National Genome Research Network is the understanding of the in vivo function of single genes and the pathophysiological and clinical consequences of respective mutations.

Early detection of diabetes retinopathy by new algorithms for automatic recognition of vascular changes.

Diabetes mellitus often results in diabetic retinopathy caused by pathological changes of the retinal vessel tree. Early detection of these changes can delay the disease. Image processing can reduce the workload of screeners and can play a central role in quality assurance tasks.

TOSCA-Imaging--developing Internet based image processing software for screening and diagnosis of diabetic retinopathy.

The primary aim of TOSCA-Imaging, which was a part of the TOSCA Project financed by EU's Fifth Framework IST Programme, was to develop Internet based software and image data bases for screening and diagnosis of diabetic retinopathy and implementing it into a real life situation. The work consisted of: 1) Construction of an Internet based communication platform for transmitting and analyzing retinal images. 2) Implementation of routines for detecting the first microaneurysm (transition from normal to pathologic), detecting patients needing referral for treatment (presence of venous beading or hard exudates near the fovea), and for serial analysis (image alignment).

Quantitative assessment of cartilage status in osteoarthritis by quantitative magnetic resonance imaging: technical validation for use in analysis of cartilage volume and further morphologic parameters.

Objective: Quantitative diagnostic tools for osteoarthritis (OA) are important for evaluating the treatment response to structure-modifying drugs. This study was undertaken to test the technical validity (accuracy) of quantitative magnetic resonance imaging (qMRI) for reliable determination of the total bone interface area, percentage of cartilaginous (denuded) joint surface area, and cartilage thickness in OA.

Methods: High-resolution MRIs of femorotibial and patellar cartilage were acquired in 21 patients prior to total knee arthroplasty, using a T1-weighted gradient-echo sequence with water excitation.

Femoro-tibial cartilage metrics from coronal MR image data: Technique, test-retest reproducibility, and findings in osteoarthritis.

MRI-based measures of cartilage morphology are being increasingly used as surrogate markers in osteoarthritis. In contrast to other knee joint surfaces, quantitative analysis of the femoral condyles from sagittal MRI suffers from limited precision. The objective, therefore, was to develop a technique for reproducible assessment of femoral cartilage morphology from coronal image data.

Correlation of knee-joint cartilage morphology with muscle cross-sectional areas vs. anthropometric variables.

We tested the hypothesis that muscle cross-sectional areas (MCSAs) are more highly (and independently) correlated with cartilage morphology than are body height and weight, and that the physiological reduction of cartilage thickness with aging is associated with a proportional, age-dependent decrease in MCSAs. In 59 asymptomatic individuals (23-75 years old), morphological parameters of the knee cartilages (volume, thickness, and bone-cartilage interface area), and MCSAs were determined from magnetic resonance imaging (MRI) data. Multiple regression models were used to calculate which proportion of the variability of the normal cartilage morphology can be predicted based on independent variables.

Relevance of arm position and muscle activity on three-dimensional glenohumeral translation in patients with traumatic and atraumatic shoulder instability.

Background: No quantitative data on glenohumeral translation exist allowing one to distinguish insufficiency of the active or passive stabilizers in different forms of shoulder instability.

Hypothesis: To determine whether 1) in traumatic or atraumatic shoulder instability an increase of glenohumeral translation can be observed in specific relevant arm positions, 2) muscle activity leads to recentering of the humeral head, and 3) there exist differences between traumatic and atraumatic instability.

Study Design: Prospective clinical trial.

Three-dimensional analysis and visualization of regional MR signal intensity distribution of articular cartilage.

The aim of this study was to develop a technique for analyzing and visualizing the regional, three-dimensional signal intensity distribution of articular cartilage in MR images, as a potential surrogate marker of structural or biochemical alterations in early osteoarthritis. Exemplary MR-images of human patellae were acquired at a resolution of 1.5 x 0.

Quantitative cartilage imaging of the human hind foot: precision and inter-subject variability.

Alterations of ankle cartilage are observed in degenerative and inflammatory joint disease, but cartilage cannot be directly visualized by radiography. The purpose of this study was therefore to analyze the feasibility and precision of quantitative cartilage imaging in the human hind foot (talocrural, talotarsal, and intertarsal joints), and to report the inter-subject variability for cartilage volume, thickness and surface areas. The feet of 16 healthy volunteers were imaged using a 3D gradient-echo magnetic resonance imaging sequence with water-excitation.

Surface size, curvature analysis, and assessment of knee joint incongruity with MRI in vivo.

The purpose of this study was to develop an MR-based technique for quantitative analysis of joint surface size, surface curvature, and joint incongruity and to assess its reproducibility under in vivo imaging conditions. The surface areas were determined after 3D reconstruction of the joint by triangulation and the incongruity by Gaussian curvature analysis. The precision was tested by analyzing four replicated MRI datasets of human knees in 14 individuals.

Glenohumeral translation during active and passive elevation of the shoulder - a 3D open-MRI study.

Despite its importance for the understanding of joint mechanics in healthy subjects and patients, there has been no three-dimensional (3D) in vivo data on the translation of the humeral head relative to the glenoid during abduction under controlled mechanical loading. The objective was therefore to analyze humeral head translation during passive and active elevation by applying an open MR technique and 3D digital postprocessing methods. Fifteen healthy volunteers were examined with an open MR system at different abduction positions under muscular relaxation (30-150 degrees of abduction) and during activity of shoulder muscles (60-120 degrees ).