Body Segment Classification for Visible Human Cross Section Slices

The U S. National Library of Medicine (NLM) has long been a world leader in the archiving and distribution of the print-based images of biology and medicine. NLM has also been a pioneer in the use of computer systems to encode and distribute textual knowledge of the life sciences. NLM's Long Range Planning effort of 1985-86 foresaw a coming era where NLM's Bibliographic and factual database services would be complemented by libraries of digital images, distributed over high speed computer networks. The NLM Planning Panel on Electronic Imaging recommended that NLM should undertake the building a digital image library consisting of computerized tomography (CT) and magnetic resonance (MR) images, and cryosection images of a representative, carefully selected and prepared male and female cadaver -- the “Visible Human Project®.” The male and female Visible Human data sets are now being made available through a license agreement with the NLM. The data sets are supporting a wide range of educational, diagnostic, treatment planning, and commercial uses. The NLM, in partnership with other U.S. government research agencies has begun a three prong effort within the Visible Human Project to address: the creation of a new online, interactive, digital head-and-neck atlas; the development of a tool kit of computational programs capable of automatically performing many of the basic data handling functions required for using Visible Human data in applications; and the improved resolution of future Visible Human data sets through the reduction of the anatomical artifacts introduced by the methods used to stabilize and section the anatomical materials and the development of staining and wide-spectrum methods for increasing tissue contrast.

Current methods for estimating and reporting radiation dose from CT examinations are largely patient-generic; the body size and hence dose variation from patient to patient is not reflected. Furthermore, the current protocol designs rely on dose as a surrogate for the risk of cancer incidence, neglecting the strong dependence of risk on age and gender. The purpose of this study was to develop a method for estimating patient-specific radiation dose and cancer risk from CT examinations. The study included two patients (a 5-week-old female patient and a 12-year-old male patient), who underwent 64-slice CT examinations (LightSpeed VCT, GE Healthcare) of the chest, abdomen, and pelvis at our institution in 2006. For each patient, a nonuniform rational B-spine (NURBS) based full-body computer model was created based on the patient's clinical CT data. Large organs and structures inside the image volume were individually segmented and modeled. Other organs were created by transforming an existing adult male or female full-body computer model (developed from visible human data) to match the framework defined by the segmented organs, referencing the organ volume and anthropometry data in ICRP Publication 89. A Monte Carlo program previously developed and validated for dose simulation on the LightSpeed VCT scanner was used to estimate patient-specific organ dose, from which effective dose and risks of cancer incidence were derived. Patient-specific organ dose and effective dose were compared with patient-generic CT dose quantities in current clinical use: the volume-weighted CT dose index (CTDIvol) and the effective dose derived from the dose-length product (DLP). The effective dose for the CT examination of the newborn patient (5.7 mSv) was higher but comparable to that for the CT examination of the teenager patient (4.9 mSv) due to the size-based clinical CT protocols at our institution, which employ lower scan techniques for smaller patients. However, the overall risk of cancer incidence attributable to the CT examination was much higher for the newborn (2.4 in 1000) than for the teenager (0.7 in 1000). For the two pediatric-aged patients in our study, CTDIvol underestimated dose to large organs in the scan coverage by 30%-48%. The effective dose derived from DLP using published conversion coefficients differed from that calculated using patient-specific organ dose values by -57% to 13%, when the tissue weighting factors of ICRP 60 were used, and by -63% to 28%, when the tissue weighting factors of ICRP 103 were used. It is possible to estimate patient-specific radiation dose and cancer risk from CT examinations by combining a validated Monte Carlo program with patient-specific anatomical models that are derived from the patients' clinical CT data and supplemented by transformed models of reference adults. With the construction of a large library of patient-specific computer models encompassing patients of all ages and weight percentiles, dose and risk can be estimated for any patient prior to or after a CT examination. Such information may aid in decisions for image utilization and can further guide the design and optimization of CT technologies and scan protocols.

Background removal is a critical step in Visible Human Data (VHD) processing, which is the basic of all other researches. In this paper, a new segmentation algorithm based on the hybrid method for VHD background removal has been proposed, which combines a feature based segmentation method with a contour based one. The algorithm first determines the background part and the interested parts of an image at a coarse level by using its colour features, and then obtains a fine segmentation by using a Gradient Vector Flow (GVF) Snake model on the previous initial contour. Our test results on Chinese VHD show that the new algorithm is more robust and accurate than the previous methods.

The D0 experiment has previously calculated its luminosities using a visible cross section (luminosity monitor constant) for its Level 0 trigger, {sigma}{sub L0} = 42.9 mb based on the E710 inelastic cross section measurements. Recently, CDF has also published inelastic cross section measurements markedly different from E710. The D0 experiment has moved to world average inelastic cross sections at {radical}s = 1.8 TeV. The result changes the D0 visible cross section to {sigma}{sub L0} = 48.2 mb which is an increase of 12.4% in the visible cross section value. The error on luminosity has been left unchanged at 12%.

The structures of superior mediastinum and their spatial relationships are complex and difficult to master. This study aimed to compare visualization of the superior mediastinum based on computed tomography (CT) images and on the thin sections of the Chinese visible human (CVH) data set to provide a sectional anatomical basis for diagnostic imaging of superior mediastinal pathology. CVH sections of the mediastinum of a 35-year old male were compared with plain and enhanced CT images of a 45-year old male without apparent abnormalities in the upper chest. In addition, a three-dimensional model based on the CVH sections was compared with a model based on CT images. Although CT imaging is noninvasive and can be carried out in many individuals, its weakness is clearly the visualization of small soft tissue structures. In this respect, the sectional anatomical approach of the CVH images is complementary, as it visualizes these small soft tissue structures due to the higher resolution in the plain of sectioning and the color of the different structures in the section. Three-dimensional surface and volume rendering of reconstructions of the CVH data set can help medical students and less experienced thoracic surgeons to familiarize themselves with the topographic anatomy of the superior mediastinal structures and their spatial relationships, and thus with interpreting CT images of patients.

The four-dimensional (4-D) NCAT phantom was developed to realistically model human anatomy based on the visible human data and cardiac and respiratory motions based on 4-D tagged magnetic resonance imaging and respiratory-gated CT data from normal human subjects. Currently, the 4-D NCAT phantom does not include the airway tree or its motion within the lungs. Also, each lung is defined with a single surface; the individual lobes are not distinguished. The authors further the development of the phantom by creating dynamic models for the individual lung lobes and for the airway tree in each lobe. NURBS surfaces for the lobes and an initial airway tree model (/spl sim/ 4 generations) were created through manual segmentation of the visible human data. A mathematical algorithm with physiological constraints was used to extend the original airway model to fill each lobe. For each parent airway branch inside a lobe, the algorithm extends the airway tree by creating two daughter branches modeled with cylindrical tubes. Parameters for the cylindrical tubes such as diameter, length, and angle are constrained based on flow parameters and available lung space.

USING MRI FOR THE IMAGING OF LONG BONES: FIRST EXPERIENCES

Multiclass skin lesion localization and classification using deep learning based features fusion and selection framework for smart healthcare

Objective. A major challenge in treatment of tumors near skeletal muscle is defining the target volume for suspected tumor invasion into the muscle. This study develops a framework that generates radiation target volumes with muscle fiber orientation directly integrated into their definition. The framework is applied to nineteen sacral tumor patients with suspected infiltration into surrounding muscles. Approach. To compensate for the poor soft-tissue contrast of CT images, muscle fiber orientation is derived from cryo-images of two cadavers from the human visible project (VHP). The approach consists of (a) detecting image gradients in the cadaver images representative of muscle fibers, (b) mapping this information onto the patient image, and (c) embedding the muscle fiber orientation into an expansion method to generate patient-specific clinical target volumes (CTV). The validation tested the consistency of image gradient orientation across VHP subjects for the piriformis, gluteus maximus, paraspinal, gluteus medius, and gluteus minimus muscles. The model robustness was analyzed by comparing CTVs generated using different VHP subjects. The difference in shape between the new CTVs and standard CTV was analyzed for clinical impact. Main results. Good agreement was found between the image gradient orientation across VHP subjects, as the voxel-wise median cosine similarity was at least 0.86 (for the gluteus minimus) and up to 0.98 for the piriformis. The volume and surface similarity between the CTVs generating from different VHP subjects was on average at least 0.95 and 5.13 mm for the Dice Similarity Coefficient and the Hausdorff 95% Percentile Index, showing excellent robustness. Finally, compared to the standard CTV with different margins in muscle and non-muscle tissue, the new CTV margins are reduced in muscle tissue depending on the chosen clinical margins. Significance. This study implements a method to integrate muscle fiber orientation into the target volume without the need for additional imaging.

Fastlim is a tool to calculate conservative limits on extensions of the Standard Model from direct LHC searches without performing any Monte Carlo event generation. The program reconstructs the visible cross sections (cross sections after event selection cuts) from pre-calculated efficiency tables and cross section tables for simplified event topologies. As a proof of concept of the approach, we have implemented searches relevant for supersymmetric models with R-parity conservation. Fastlim takes the spectrum and coupling information of a given model point and provides, for each signal region of the implemented analyses, the visible cross sections normalised to the corresponding upper limit, reported by the experiments, as well as the mathrm{CL}_mathrm{s} value. To demonstrate the utility of the program we study the sensitivity of the recent ATLAS missing energy searches to the parameter space of natural SUSY models. The program structure allows the straightforward inclusion of external efficiency tables and can be generalised to R-parity violating scenarios and non-SUSY models. This paper serves as a self-contained user guide and indicates the conventions and approximations used.

We develop a realistic computerized torso phantom for use in medical imaging research. The phantom has the potential to model anatomical variations and patient motion more realistically than phantoms based on simple geometric primitives. Structures are defined basing nonuniform rational B-spline (NURBS) surfaces, as used in 3D computer graphics. By fitting NURBS to patient data, the phantom is more realistic than those based on solid geometry. Points on the surfaces of the different structures in the torso except the heart were selected from the Visible Human Project CT data set, National Library of Medicine. Polygon surfaces were fit to the points for each structure and smoothed. 3D NURBS surfaces were fit to the smooth polygon surfaces. The heart model was generated with 4D NURBS as described in a previous study. The control points defining each NURBS surface can be manipulated to model anatomical variations and patient motion.

CURRENT STATUS OF CARDIOVASCULAR IMAGING BY TRANSMISSION COMPUTED TOMOGRAPHY*William R. BrodyDepartments of Radiology and Electrical EngineeringStanford University School of MedicineStanford, CaliforniaAbstractAlthough the technological advances in transmission computed tomography (CT)have been dramatic, cardiovascular applications of CT are currently limited by in-adequate temporal resolution to resolve moving structures (e.g., the myocardium),difficulties in timing the scan exposure to coincide with maximum contrast en-hancement of vascular structures and cardiac chambers, and limited field of viewperpendicular to the axial plane. The modes of cardiac CT operation are reviewed:static (single scan), dynamic (multiple scans in rapid succession), gated andrapid (scans <500 msec). Modest improvements in gated and dynamic scanning areexpected with existing technology and optimization of reconstruction algorithms.Future advances in CT technology should be directed toward the development ofrapid scanning systems for imaging the myocardium and toward higher resolutionscanners for imaging vascular structures.IntroductionSince the introduction of the first device for computed tomography, peoplehave speculated on the potential application of CT for imaging the cardiovascularsystem. With the advance of CT technology into third and fourth generation pro-duction models, cardiovascular applications have become feasible. However, theuse of CT for imaging the heart and blood vessels is in its embryonic state, pend-ing better understanding of ways in which temporal and spatial resolution of CTcan be improved to advance the state of the art. It is the purpose of this paperto outline the current status of cardiovascular computed tomography, indicatingthe limitations of current methods, and to point out directions for the future ofthis exciting application.Computed tomography offers two important advantages for cardiovascular imaging:exceedingly fine density resolution (the ability to measure small differences inthe x -ray attenuation coefficient of tissues), and a cross -sectional imaging for-mat. The major impact of these two advantages is the ability of CT to createblood pool images which outline the heart and blood vessels following the intra-venous injection of modest amounts of iodine -containing contrast agents (0.15-0.25 g iodine /kg). Without this iodine sensitivity, cardiovascular CT would beof limited value, since the differences in the x -ray attenuation coefficients ofblood and muscle are too small to be distinguished by CT without exogenous con-trast medium (iodine) administration.While the use of intravascular iodine for contrast enhancement is common to allforms of CT, there are certain aspects of contrast enhancement that are peculiarto cardiovascular applications. First, a bolus injection is preferred to continu-ous infusion, to permit maximum enhancement of vascular structures. Bolus intra-venous iodine injections introduce serious difficulties in timing the CT exposureto correspond with the appropriate time when the blood level of iodine is maximalin the region of interest. Second, the dynamic change in iodine concentration(and hence x -ray attenuation) following bolus injection provides important physio-logic information about tissue perfusion that can be utilized with a speciallydesigned scanner.The use of a cross -sectional imaging format is not necessarily optimal. Forexample, the tortuous course of arteries is often better appreciated from twoorthogonal projection images rather than a series of axial cross sections. None-theless, the cross -sectional format of CT is important for removing interferencefrom surrounding bone and soft tissues, which normally would obscure the informa-tion contained in the low concentrations of iodine which are imaged with CT.Future applications for blood vessel imaging have been proposed to utilize someof the features of CT imaging for sensitive iodine detection, coupled with a pro-jectional imaging format.* This work was supported by a Grant -in -Aid from the American Heart Associationand with funds contributed in part by the Santa Clara County Heart Association.

Horseshoe crabs have been identified as one of the marine species that contribute greatly to scientific advances especially in haematological studies.Besides the haemocytes of these creatures, they are also well known for their protein contents in the perivitelline fluid (PVF).Due to this, over the years, there has been increasing interests in the scientific community to explore the function of proteins in the PVF of horseshoe crab for applications in various biomedical areas such as immunology, embryology and tissue or cell engineering.This article will review the two main protein components found in the PVF of the horseshoe crab namely, lectins, and hemocyanins with regards to its applications in medical research.

Intrabody communication (IBC) is a promising approach for realizing information transmission among various wearable or implantable devices within bodyNET. The existing IBC studies are limited to the local or abstract geometric channel model, which is limited to providing efficient channel characteristics for the various transmitting scenarios. The aim of this article is to reconstruct a whole-body model with anatomical features and combine the field-circuit model for investigating the human channel characteristics. A visible human data (VHD) is established by segmentation and 3-D reconstruction of layered tissues. The transmission attenuation was simulated and analyzed through the finite element method. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">In vivo</i> experiments and phantom experiments were implemented to validate the simulation results. For the on-body communication, the transmission attenuation of the short distance was similar to the low-pass filter’s amplitude-frequency characteristics. For the implantable communication, the consistency coefficient of the attenuation between in-body to on-body and on-body to in-body was higher than 98%, indicating that the body channel is bidirectional. This work provides a repeatable and verified VHD-based whole-body model for the human channel attenuation investigation. It is an essential step for the further development of IBC, such as the transceiver design and the multinodes’ protocol for bodyNET.

3D Active Net, which is a 3D extension of Snakes, is an energy-minimizing surface model which can extract a volume of interest from 3D volume data. It is deformable and evolves in 3D space to be attracted to salient features, according to its internal and image energy. The net can be fitted to the contour of a target object by defining the image energy suitable for the contour property. We present testing results of the extraction of a muscle from the Visible Human Data by two methods: manual segmentation and the application of 3D Active Net. We apply principal component analysis, which utilizes the color information of the 3D volume data to emphasize an ill-defined contour of the muscle, and then apply 3D Active Net. We recognize that the extracted object has a smooth and natural contour in contrast with a comparable manual segmentation, proving an advantage of our approach.