Automation of Hessian-Based Tubularity Measure Response Function in 3D Biomedical Images

The blood vessels and nerve trees consist of tubular objects interconnected into a complex tree- or web-like structure that has a range of structural scale 5 μm diameter capillaries to 3 cm aorta. This large-scale range presents two major problems; one is just making the measurements, and the other is the exponential increase of component numbers with decreasing scale. With the remarkable increase in the volume imaged by, and resolution of, modern day 3D imagers, it is almost impossible to make manual tracking of the complex multiscale parameters from those large image data sets. In addition, the manual tracking is quite subjective and unreliable. We propose a solution for automation of an adaptive nonsupervised system for tracking tubular objects based on multiscale framework and use of Hessian-based object shape detector incorporating National Library of Medicine Insight Segmentation and Registration Toolkit (ITK) image processing libraries

Image reconstruction from limited angle projections collected by multisource interior x-ray imaging systems

A multi-source x-ray interior imaging system with limited angle scanning is investigated to study the possibility of building an ultra-fast micro-CT for dynamic small animal imaging. And two methods are employed to perform interior reconstruction from a limited number of projections collected by the multi-source interior x-ray system. The first is total variation minimization with the steepest descent search (TVM-SD) and the second is total difference minimization with soft-threshold filtering (TDM-STF). Comprehensive numerical simulations and animal studies are performed to validate the associated reconstructed methods and demonstrate the feasibility and application of the proposed system configuration. The image reconstruction results show that both of the two reconstruction methods can significantly improve the image quality and the TDM-SFT is slightly superior to the TVM-SD. Finally, quantitative image analysis shows it is possible to make an ultra-fast micro-CT using a multi-source interior x-ray system scheme combined with the state-of-the-art interior tomography

Ultra high-speed transaxial image reconstruction of the heart, lungs, and circulation via numerical approximation methods and optimized processor architecture

A high temporal resolution scanning multiaxial tomography unit, the Dynamic Spatial Reconstructor (DSR), presently under development will be capable of recording multiangular X-ray projection data of sufficient axial range to reconstruct a cylindrical volume consisting of up to 240 contiguous 1-mm thick cross sections encompassing the intact thorax. At repetition rates of up to 60 sets of cross sections per second, the DSR will thus record projection data sufficient to reconstruct as many as 14 400 cross-sectional images during each second of operation. Use of this system in a clinical setting will be dependent upon the development of software and hardware techniques for carrying out X-ray reconstructions at the rate of hundreds of cross sections per second. A conceptual design, with several variations, is proposed for a special purpose hardware reconstruction processor capable of completing a single cross section reconstruction within 1 to 2 msec. In addition, it is suggested that the amount of computation required to execute the filtered back-projection algorithm may be decreased significantly by the utilization of approximation equations, formulated as recursions, for the generation of internal constants required by the algorithm. The effects on reconstructed image quality of several different approximation methods are investigated by reconstruction of density projections generated from a mathematically simulated model of the human thorax, assuming the same source-detector geometry and X-ray flux density as will be employed by the DSR. These studies have indicated that the prudent application of numerical approximations for the generation of internal constants will not cause significant degradation in reconstructed image quality and will in fact require substantially less auxiliary memory and computational capacity than required by direct execution of mathematically exact formulations of the reconstruction algorithm.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23631/1/0000595.pd

Intravascular cell delivery device for therapeutic VEGF-induced angiogenesis in chronic vascular occlusion

AbstractSite specific targeting remains elusive for gene and stem cell therapies in the cardiovascular field. One promising option involves use of devices that deliver larger and more sustained cell/gene payloads to specific disease sites using the versatility of percutaneous vascular access technology. Smooth muscle cells (SMCs) engineered to deliver high local concentrations of an angiogenic molecule (VEGF) were placed in an intravascular cell delivery device (ICDD) in a porcine model of chronic total occlusion (CTO) involving ameroid placement on the proximal left circumflex (LCx) artery. Implanted SMC were retained within the ICDD and were competent for VEGF production in vitro and in vivo. Following implantation, micro-CT analyses revealed that ICDD-VEGF significantly enhanced vasa vasora microvessel density with a concomitant increase in tissue VEGF protein levels and formation of endothelial cell colonies suggesting increased angiogenic potential. ICDD-VEGF markedly enhanced regional blood flow determined by microsphere and contrast CT analysis translating to a functional improvement in regional wall motion and global left ventricular (LV) systolic and diastolic function. Our data indicate robust, clinically relevant angiogenesis can be achieved in a human scale porcine chronic vascular occlusion model following ICDD-VEGF-based delivery of angiogenic cells. This may have implications for percutaneous delivery of numerous therapeutic factors promoting creation of microvascular bypass networks in chronic vaso-occlusive diseases

Improved Siderotic Nodule Detection in Cirrhosis with Susceptibility-Weighted Magnetic Resonance Imaging: A Prospective Study

BACKGROUND: Hepatic cirrhosis is a common pathway of progressive liver destruction from multiple causes. Iron uptake can occur within the hepatic parenchyma or within the various nodules that form in a cirrhotic liver, termed siderotic nodules. Siderotic nodule formation has been shown to correlate with inflammatory activity, and while the relationship between siderotic nodule formation and malignancy remains unclear, iron distribution within hepatic nodules has known implications for the detection of hepatocellular carcinoma. We aimed to evaluate the role of abdominal susceptibility-weighted imaging in the detection of siderotic nodules in cirrhotic patients. METHODOLOGY/PRINCIPAL FINDINGS: Forty-six (46) cirrhotic patients with at least one siderotic nodule detected on previous imaging underwent both computed tomography and magnetic resonance imaging (T1-, T2-, T2*-, and susceptibility-weighted imaging) at 3.0 Tesla. Imaging data was independently analyzed by two radiologists. Siderotic nodule count was determined for each modality and imaging sequence. For each magnetic resonance imaging technique, siderotic nodule conspicuity was assessed on a 3 point scale (1 = weak, 2 = moderate, 3 = strong). More nodules were detected by susceptibility weighted imaging (n = 2935) than any other technique, and significantly more than by T2* weighted imaging (n = 1696, p<0.0001). Lesion conspicuity was also highest with susceptibility-weighted imaging, with all nodules found to be moderate (n = 6) or strong (n = 40); a statistically significant difference (p<0.001). CONCLUSIONS: Susceptibility-weighted imaging had the greatest lesion conspicuity and detected the highest number of siderotic nodules suggesting it is the most sensitive imaging technique to detect siderotic nodules in cirrhotic patients

Computed Tomography Measurement of Rib Cage Morphometry in Emphysema

Background: Factors determining the shape of the human rib cage are not completely understood. We aimed to quantify the contribution of anthropometric and COPD-related changes to rib cage variability in adult cigarette smokers. Methods: Rib cage diameters and areas (calculated from the inner surface of the rib cage) in 816 smokers with or without COPD, were evaluated at three anatomical levels using computed tomography (CT). CTs were analyzed with software, which allows quantification of total emphysema (emphysema%). The relationship between rib cage measurements and anthropometric factors, lung function indices, and %emphysema were tested using linear regression models. Results: A model that included gender, age, BMI, emphysema%, forced expiratory volume in one second (FEV1)%, and forced vital capacity (FVC)% fit best with the rib cage measurements (R2  = 64% for the rib cage area variation at the lower anatomical level). Gender had the biggest impact on rib cage diameter and area (105.3 cm2; 95% CI: 111.7 to 98.8 for male lower area). Emphysema% was responsible for an increase in size of upper and middle CT areas (up to 5.4 cm2; 95% CI: 3.0 to 7.8 for an emphysema increase of 5%). Lower rib cage areas decreased as FVC% decreased (5.1 cm2; 95% CI: 2.5 to 7.6 for 10 percentage points of FVC variation). Conclusions: This study demonstrates that simple CT measurements can predict rib cage morphometric variability and also highlight relationships between rib cage morphometry and emphysema

Herniation Pits in Human Mummies: A CT Investigation in the Capuchin Catacombs of Palermo, Sicily

Herniation pits (HPs) of the femoral neck were first described in a radiological publication in 1982 as round to oval radiolucencies in the proximal superior quadrant of the femoral neck on anteroposterior radiographs of adults. In following early clinical publications, HPs were generally recognized as an incidental finding. In contrast, in current clinical literature they are mentioned in the context of femoroacetabular impingement (FAI) of the hip joint, which is known to cause osteoarthritis (OA). The significance of HPs in chronic skeletal disorders such as OA is still unclear, but they are discussed as a possible radiological indicator for FAI in a large part of clinical studies