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Sample records for anatomic landmarks based

  1. Collaborative regression-based anatomical landmark detection

    Science.gov (United States)

    Gao, Yaozong; Shen, Dinggang

    2015-12-01

    Anatomical landmark detection plays an important role in medical image analysis, e.g. for registration, segmentation and quantitative analysis. Among the various existing methods for landmark detection, regression-based methods have recently attracted much attention due to their robustness and efficiency. In these methods, landmarks are localised through voting from all image voxels, which is completely different from the classification-based methods that use voxel-wise classification to detect landmarks. Despite their robustness, the accuracy of regression-based landmark detection methods is often limited due to (1) the inclusion of uninformative image voxels in the voting procedure, and (2) the lack of effective ways to incorporate inter-landmark spatial dependency into the detection step. In this paper, we propose a collaborative landmark detection framework to address these limitations. The concept of collaboration is reflected in two aspects. (1) Multi-resolution collaboration. A multi-resolution strategy is proposed to hierarchically localise landmarks by gradually excluding uninformative votes from faraway voxels. Moreover, for informative voxels near the landmark, a spherical sampling strategy is also designed at the training stage to improve their prediction accuracy. (2) Inter-landmark collaboration. A confidence-based landmark detection strategy is proposed to improve the detection accuracy of ‘difficult-to-detect’ landmarks by using spatial guidance from ‘easy-to-detect’ landmarks. To evaluate our method, we conducted experiments extensively on three datasets for detecting prostate landmarks and head & neck landmarks in computed tomography images, and also dental landmarks in cone beam computed tomography images. The results show the effectiveness of our collaborative landmark detection framework in improving landmark detection accuracy, compared to other state-of-the-art methods.

  2. MRI-based anatomical landmarks for the identification of thoracic vertebral levels

    International Nuclear Information System (INIS)

    Aim: To identify soft-tissue and bony anatomical landmarks on dedicated thoracic spine magnetic resonance imaging (MRI), and to assess their detectability, reproducibility, and accuracy in predicting specific thoracic vertebral levels. Materials and methods: One hundred dedicated thoracic MRI studies were retrospectively analysed by two radiologists independently. Ten bone and soft-tissue landmarks were localized to the adjacent vertebral level. The true numerical thoracic vertebral level was subsequently determined and recorded by cross referencing with a sagittal cervico-thoracic “counting scan”. Results: Six landmarks were defined in ?98% cases; however, there was a low interobserver percentage agreement for the defined vertebral levels (>70% for only one landmark). The most useful landmark for defining a specific vertebral level was the most superior rib (98% detection, 95% interobserver agreement, 98% at a single vertebral level, 0.07 SD). Eight landmarks localized to a specific thoracic segment in only 16–44% of cases, with a standard deviation of >0.5 vertebral levels and with a range which was greater than four vertebral levels. Conclusion: The C2 vertebra must be identified and cross referenced to the dedicated thoracic spine MRI, as other MRI-based anatomical landmarks are unreliable in determining the correct thoracic vertebral level

  3. MR-guided stereotactic neurosurgery-comparison of fiducial-based and anatomical landmark transformation approaches

    International Nuclear Information System (INIS)

    For application in magnetic resonance (MR) guided stereotactic neurosurgery, two methods for transformation of MR-image coordinates in stereotactic, frame-based coordinates exist: the direct stereotactic fiducial-based transformation method and the indirect anatomical landmark method. In contrast to direct stereotactic MR transformation, indirect transformation is based on anatomical landmark coregistration of stereotactic computerized tomography and non-stereotactic MR images. In a patient study, both transformation methods have been investigated with visual inspection and mutual information analysis. Comparison was done for our standard imaging protocol, including t2-weighted spin-echo as well as contrast enhanced t1-weighted gradient-echo imaging. For t2-weighted spin-echo imaging, both methods showed almost similar and satisfying performance with a small, but significant advantage for fiducial-based transformation. In contrast, for t1-weighted gradient-echo imaging with more geometric distortions due to field inhomogenities and gradient nonlinearity than t2-weighted spin-echo imaging, mainly caused by a reduced bandwidth per pixel, anatomical landmark transformation delivered markedly better results. Here, fiducial-based transformation yielded results which are intolerable for stereotactic neurosurgery. Mean Euclidian distances between both transformation methods were 0.96 mm for t2-weighted spin-echo and 1.67 mm for t1-weighted gradient-echo imaging. Maximum deviations were 1.72 mm and 3.06 mm, respectively

  4. Automatic categorization of anatomical landmark-local appearances based on diffeomorphic demons and spectral clustering for constructing detector ensembles.

    Science.gov (United States)

    Hanaoka, Shouhei; Masutani, Yoshitaka; Nemoto, Mitsutaka; Nomura, Yukihiro; Yoshikawa, Takeharu; Hayashi, Naoto; Ohtomo, Kuni

    2012-01-01

    A method for categorizing landmark-local appearances extracted from computed tomography (CT) datasets is presented. Anatomical landmarks in the human body inevitably have inter-individual variations that cause difficulty in automatic landmark detection processes. The goal of this study is to categorize subjects (i.e., training datasets) according to local shape variations of such a landmark so that each subgroup has less shape variation and thus the machine learning of each landmark detector is much easier. The similarity between each subject pair is measured based on the non-rigid registration result between them. These similarities are used by the spectral clustering process. After the clustering, all training datasets in each cluster, as well as synthesized intermediate images calculated from all subject-pairs in the cluster, are used to train the corresponding subgroup detector. All of these trained detectors compose a detector ensemble to detect the target landmark. Evaluation with clinical CT datasets showed great improvement in the detection performance. PMID:23286038

  5. Anatomic Landmarks for the First Dorsal Compartment

    OpenAIRE

    Hazani, Ron; Engineer, Nitin J.; Cooney, Damon; Wilhelmi, Bradon J

    2009-01-01

    Objective: Knowledge of anatomic landmarks for the first dorsal compartment can assist clinicians with management of de Quervain's disease. The radial styloid, the scaphoid tubercle, and Lister's tubercle can be used as superficial landmarks for the first dorsal compartment. Methods: Thirty-two cadaveric wrists were dissected, and measurements were taken from the predetermined landmarks to the extensor retinaculum. The compartments were also inspected for variability of the abductor pollicis ...

  6. Computed Tomography Analysis of Postsurgery Femoral Component Rotation Based on a Force Sensing Device Method versus Hypothetical Rotational Alignment Based on Anatomical Landmark Methods: A Pilot Study

    OpenAIRE

    Kreuzer, Stefan W.; Amir Pourmoghaddam; Leffers, Kevin J.; Clint W. Johnson; Marius Dettmer

    2016-01-01

    Rotation of the femoral component is an important aspect of knee arthroplasty, due to its effects on postsurgery knee kinematics and associated functional outcomes. It is still debated which method for establishing rotational alignment is preferable in orthopedic surgery. We compared force sensing based femoral component rotation with traditional anatomic landmark methods to investigate which method is more accurate in terms of alignment to the true transepicondylar axis. Thirty-one patients ...

  7. Pterion: An anatomical variation and surgical landmark

    Directory of Open Access Journals (Sweden)

    Prashant E Natekar

    2011-01-01

    Full Text Available Introduction : The frontal and the parietal bones superiorly and the greater wing of the sphenoid and the squamous temporal inferiorly of one side meet at an H-shaped sutural junction termed the pterion. This is an important anatomical and anthropological landmark as it overlies both the anterior branch of middle meningeal artery and the lateral fissure of the cerebral hemisphere. The knowledge of sutural joints between frontal, parietal, sphenoid and temporal bones at pterion is clinically, radiologically and surgically important during surgical interventions involving burr hole surgeries. Materials and Methods : Study performed on 150 dry temporal bones. The pterion, and its sutural articulations with frontal, parietal, sphenoid and temporal bones and also anatomical variations, if any, were studied. Results : Four types of pterion, i.e. sphenoparietal, frontotemporal, stellate and epipteric, were observed. Conclusions : The knowledge of the variations of pterion and its surgical anatomy, in Indian population are important for surgeons operating in the fieldThe present study will also contribute additional information of skull bone fractures in infancy and early childhood, which may be associated with large intersutural bones giving false appearance of fracture radiologically and also during surgical interventions involving burr hole surgeries, as their extensions may lead to continuation of fracture lines.

  8. Interventional guidance for cardiac resynchronization therapies: merging anatomic X-ray imaging with functional ultrasound imaging based on mutually-shared landmarks

    International Nuclear Information System (INIS)

    Detailed knowledge of cardiac anatomy and function is required for complex cardiac electrophysiology interventions. Cardiac resynchronization therapies (CRT), for example, requires information about coronary venous anatomy for left ventricular lead placement. In CRT, heart failure patients are equipped with dual-chamber pacemakers in order to improve cardiac output and heart failure symptoms. Cardiac function is mainly assessed with Ultrasound imaging. Fusion of complementary information from X-ray and ultrasound is an essential step towards fully utilizing all available information for CRT guidance. We present an approach for fusion of anatomical information (coronary vein structure) from X-ray with functional information (left ventricular deformation and dynamics) from ultrasound. We propose an image-based fusion approach based on mutually-shared landmarks which enable registration of both imaging spaces without the need for external tracking. (orig.)

  9. Application of Soft Tissue Artifact Compensation Using Displacement Dependency between Anatomical Landmarks and Skin Markers

    OpenAIRE

    Taebeum Ryu

    2012-01-01

    Soft tissue artifact is known to be one of the main sources of errors in motion analysis by means of stereophotogrammetry. Among many approaches to reduce such errors, one is to estimate the position of anatomical landmarks during a motion with joint angle or displacement of skin markers, which is the so-called compensation method of anatomical landmarks. The position of anatomical landmarks was modeled from the data of the so-called dynamic calibration, in which anatomical landmark positions...

  10. Estimation of the central position of the prostate-gland based on anatomical landmarks in X-ray CT images

    International Nuclear Information System (INIS)

    Robust segmentation of pelvic organ in non-contrast CT image has been required for developing computer-aided diagnosis systems. We proposed a method to normalize the position of the pelvis based on anatomical point (LM) of pelvic bones and use those LMs to estimate central position of prostate-gland in CT images in preview works. However, the evaluation of LM placement and procedure was insufficient. In this study, we aim to investigate the effective LM location and the apply different methods for identifying the prostate center positions. In the experiment, we applied three methods to 75 cases of CT images using the different number of LMs. The distances between the estimated central positions of the prostate to the human input was regarded as estimation error. The result showed that the average estimation-error of the prostate central positions was about 5 [mm] when using 12 LMs. Furthermore, we confirmed that the estimated center coordinates of the prostate exist within the prostate-gland regions in all CT cases. (author)

  11. Safe Treatment of Trigger Thumb With Longitudinal Anatomic Landmarks

    OpenAIRE

    Hazani, Ron; Elston, Josh; Whitney, Ryan D.; Redstone, Jeremiah; Chowdhry, Saeed; Wilhelmi, Bradon J

    2010-01-01

    Objective: Stenosing tenosynovitis of the thumb flexor tendon sheath is also known as trigger thumb. It is an inflammatory process that involves the flexor tendon sheath at the A1 pulley. Successful percutaneous or open treatment of trigger thumb depends on the ability of the clinician to properly predict the location of the A1 pulley. Longitudinal anatomic landmarks can facilitate safe treatment for the trigger thumb while circumventing injury to the neurovascular bundles. Methods: Fourteen ...

  12. Cardiac Conduction System: Delineation of Anatomic Landmarks With Multidetector CT

    OpenAIRE

    Farhood Saremi; Maria Torrone; Nooshin Yashar

    2009-01-01

    Major components of the cardiac conduction system including the sinoatrial node (SAN), atrioventricular node (AVN), the His Bundle, and the right and left bundle branches are too small to be directly visualized by multidetector CT (MDCT) given the limited spatial resolution of current scanners. However, the related anatomic landmarks and variants of this system a well as the areas with special interest to electrophysiologists can be reliably demonstrated by MDCT. Some of these structures and ...

  13. Robust anatomical landmark detection with application to MR brain image registration.

    Science.gov (United States)

    Han, Dong; Gao, Yaozong; Wu, Guorong; Yap, Pew-Thian; Shen, Dinggang

    2015-12-01

    Comparison of human brain MR images is often challenged by large inter-subject structural variability. To determine correspondences between MR brain images, most existing methods typically perform a local neighborhood search, based on certain morphological features. They are limited in two aspects: (1) pre-defined morphological features often have limited power in characterizing brain structures, thus leading to inaccurate correspondence detection, and (2) correspondence matching is often restricted within local small neighborhoods and fails to cater to images with large anatomical difference. To address these limitations, we propose a novel method to detect distinctive landmarks for effective correspondence matching. Specifically, we first annotate a group of landmarks in a large set of training MR brain images. Then, we use regression forest to simultaneously learn (1) the optimal sets of features to best characterize each landmark and (2) the non-linear mappings from the local patch appearances of image points to their 3D displacements towards each landmark. The learned regression forests are used as landmark detectors to predict the locations of these landmarks in new images. Because each detector is learned based on features that best distinguish the landmark from other points and also landmark detection is performed in the entire image domain, our method can address the limitations in conventional methods. The deformation field estimated based on the alignment of these detected landmarks can then be used as initialization for image registration. Experimental results show that our method is capable of providing good initialization even for the images with large deformation difference, thus improving registration accuracy. PMID:26433614

  14. Reliability of a coordinate system based on anatomical landmarks of the maxillofacial skeleton. An evaluation method for three-dimensional images obtained by cone-beam computed tomography

    International Nuclear Information System (INIS)

    We propose a method for evaluating the reliability of a coordinate system based on maxillofacial skeletal landmarks and use it to assess two coordinate systems. Scatter plots and 95% confidence ellipses of an objective landmark were defined as an index for demonstrating the stability of the coordinate system. A head phantom was positioned horizontally in reference to the Frankfurt horizontal and occlusal planes and subsequently scanned once in each position using cone-beam computed tomography. On the three-dimensional images created with a volume-rendering procedure, six dentists twice set two different coordinate systems: coordinate system 1 was defined by the nasion, sella, and basion, and coordinate system 2 was based on the left orbitale, bilateral porions, and basion. The menton was assigned as an objective landmark. The scatter plot and 95% ellipse of the menton indicated the high-level reliability of coordinate system 2. The patterns with the two coordinate systems were similar between data obtained in different head positions. The method presented here may be effective for evaluating the reliability (reproducibility) of coordinate systems based on skeletal landmarks. (author)

  15. Preliminary study of automatic detection method for anatomical landmarks in body trunk CT images

    International Nuclear Information System (INIS)

    In the research field of medical image processing and analysis, it is important to develop medical image understanding methods which are robust for individual and case differences, since they often interfere with accurate medical image processing and analysis. Location of anatomical landmarks, which are localized regions with anatomical reference to the human body, allows for robust medical understanding since the relative position of anatomical landmarks is basically the same among cases. This is a preliminary study for detecting anatomical point landmarks by using a technique of local area model matching. The model for matching process, which is called appearance model, shows the spatial appearance of voxel values at the detection target landmark and its surrounding region, while the Principal Component Analysis (PCA) is used to train appearance models. In this study, we experimentally investigate the optimal appearance model for landmark detection and analyze detection accuracy of anatomical point landmarks. (author)

  16. Anatomical landmarks accurately determine interfractional lymph node shifts during radiotherapy of lung cancer patients

    International Nuclear Information System (INIS)

    Background and purpose: Low contrast in the cone-beam computed tomography (CBCT) scans hampers fast online evaluation of interfractional changes in the lymph node position on a daily basis. In this study we have investigated whether high-contrast anatomical landmarks in the vicinity of the nodes may be used as surrogates for the lymph node positions. Materials and methods: Forty lung cancer patients were treated with an online CBCT-based setup strategy involving soft-tissue match on the primary tumor. One hundred and sixteen lymph nodes were delineated separately on the planning-CT scans and categorized according to the lymph node stations. Five anatomical landmarks were selected as surrogate structures and assigned to the individual nodes. In addition, the carina was delineated. Registrations between the planning-CT and the daily CBCTs were performed retrospectively and positional deviations between the nodes and the surrogate structures or the carina were registered. Results: The mean displacement between lymph nodes and surrogate structures was 1.6 mm with systematic/random errors of 0.7/0.7 mm, significantly smaller than the mean displacement between nodes and the carina. Conclusions: The position of the lymph nodes can be evaluated using selected anatomical landmarks on a daily basis using CBCT

  17. Value of anatomical landmarks in single-nostril endonasal transnasal-sphenoidal surgery

    OpenAIRE

    WEI, LIANG-FENG; ZHANG, JINCHAO; CHEN, HONG-JIE; WANG, RUMI

    2013-01-01

    The sphenoid sinus occupies a central location in transsphenoidal surgery (TSS). It is important to identify relevant anatomical landmarks to enter the sphenoid sinus and sellar region properly. The aim of this study was to identify anatomical landmarks and their value in single-nostril endonasal TSS. A retrospective study was performed to review 148 cases of single-nostril endonasal TSS for pituitary lesions. The structure of the nasal cavities and sphenoid sinus, the position of apertures o...

  18. Autonomous Robot Navigation based on Visual Landmarks

    DEFF Research Database (Denmark)

    Livatino, Salvatore

    The use of landmarks for robot navigation is a popular alternative to having a geometrical model of the environment through which to navigate and monitor self-localization. If the landmarks are defined as special visual structures already in the environment then we have the possibility of fully autonomous navigation and self-localization using automatically selected landmarks. The thesis investigates autonomous robot navigation and proposes a new method which benefits from the potential of the visual sensor to provide accuracy and reliability to the navigation process while relying on naturally available environment features (natural landmarks). The goal is also to integrate techniques and algorithms (also related to other research field) in the same navigation system, in order to improve localization performance and system autonomy. The proposed localization strategy is based on a continuous update of the estimated robot position while the robot is moving. In order to make the system autonomous, both acquisition and observation of landmarks have to be carried out automatically. The thesis consequently proposes a method for learning and navigation of a working environment and it explores automatic acquisition and recognition of visual landmarks. In particular, a two-phase procedure is proposed: first phase is for an automatic acquisition of visual-landmarks, second phase is for estimating robot position during navigation (based on the acquired landmarks). The feasibility and applicability of the proposed method is based on a system with a simple setup. The novelty and potentiality, are in combining algorithms for panoramic view-synthesis, attention selection, stereo reconstruction, triangulation, optimal triplet selection, and image-based rendering. Experiments demonstrate that the system can automatically learn and store visual landmarks, and later recognize these landmarks from arbitrary positions and thus estimate robot position and heading.

  19. Reproducibility of imaging skull anatomic landmarks utilizing three-dimensional computed tomography

    International Nuclear Information System (INIS)

    The study investigated the reproducibility of locating specific anatomic landmarks, utilizing computed tomography (CT), for the purpose of assigning accurate coordinates on the skull. Three-dimensional (3-D) CT data, obtained by scanning a dry adult skull, were processed using a multi-planar reconstruction (MPR) system. Each landmark was identified five times by the same technician, and the average distances between points identifying the same landmark were calculated. The 15 landmarks studied were the infra-orbital foramina, the external auditory meatus, the foramina rotundum, the foramina ovale, the optic canals, anterior crinoid processes, anterior nasal spine, crista galli, and the sella turcica. Three additional artificial markers placed in occlusal dental splints were also examined. The crinoid processes were identified with the highest degree of accuracy. The crista galli and optic canals were also located with reproducible results. The standard deviation calculated from the fine attempts to locate the artificial markers was smaller than that calculated from attempts to identify any of the landmarks. This implies that coordinates on the craniofacial bones should be defined using artificial markers rather than bony landmarks. Artificial markers placed in occlusal dental splints easily can be applied clinically. Complicated facial bone contours should be analyzed mathematically. In clinical setting, these points were found to be reproducible in 15 bony landmarks on the skull. (N.K.)

  20. Propagation of anatomical landmark misplacement to knee kinematics: performance of single and double calibration.

    Science.gov (United States)

    Stagni, Rita; Fantozzi, Silvia; Cappello, Angelo

    2006-10-01

    Soft tissue artefact and anatomical landmark misplacement have been recognized as the most critical sources of error in gait analysis. The double calibration method was recently proposed to compensate for soft tissue artefact in knee kinematics. This compensation method resulted very effective in the absence of anatomical landmark misplacement. The purpose of the present work was to assess the effectiveness of double calibration in reducing the effects of skin motion artefact on knee rotations and translations when anatomical landmark misplacement is present on the thigh and shank. The double calibration method was used to calculate knee kinematics of two subjects while they performed several motor tasks. The results were compared with those from conventional single calibration. The soft tissue artefact propagated to knee kinematics was quantified by simulating different misplacement errors using both single and double calibration. The double calibration method performed much better than the single calibration one in quantifying knee rotations and particularly translations, with misplacement error up to 15mm superimposed on the anatomical coordinates of the epicondyles. If misplacement errors were limited to just 5mm, the double calibration would be effective in providing kinematics accurate enough for orthopaedic biomechanic applications. PMID:16934471

  1. Are anatomical landmark measurements accurate for predicting endotracheal tube depth?

    Directory of Open Access Journals (Sweden)

    Devanand Mangar

    2013-03-01

    Full Text Available Background: A traditional method for depth of intubation in adult patients is taping the endotracheal tube (ETT at the upper incisors a distance of 21 or 23 cm for women and men respectively (21/23 method. A novel “topographical” measurement for estimating proper intubation depth has been suggested as a better depth predictor compared to the 21/23 method.   Objectives: To compare the 21/23 method to topographical measurements. Methods: 100 ASA physical status I-II patients scheduled for elective surgery were enrolled. The 21/23 method was initially utilized for intubation and the ETT tip to carina distance was then fiberoptically measured. Anatomical (topographical measurements were then obtained from each patient by adding the distance from the corner of the mouth to the mandibular angle to the distance from the mandibular angle to the center of the sternal notch and were recorded as the topographical intubation depth. Both measurements were assessed for percentage of ETTs that fell outside of our desired tip to carina range of 2-4 cm. Results: After the 21/23 method, 29% of ETTs fell outside our desired tip to carina range compared to 47% of ETTs with the topographical method (p=0.010. No correlation was found between the topographical measurements and airway length (upper incisors to vocal cords (r=0.248. Conclusions: Topographical measurements were not re-confirmed as an accurate intubation method and were found to be less reliable than the 21/23 method. We maintain that regardless of ETT insertion method utilized, the gold standard to ensure accurate ETT placement is fiberoptic inspection.

  2. Anatomic Landmarks Versus Fiducials for Volume-Staged Gamma Knife Radiosurgery for Large Arteriovenous Malformations

    International Nuclear Information System (INIS)

    Purpose: The purpose of this investigation was to compare the accuracy of using internal anatomic landmarks instead of surgically implanted fiducials in the image registration process for volume-staged gamma knife (GK) radiosurgery for large arteriovenous malformations. Methods and Materials: We studied 9 patients who had undergone 10 staged GK sessions for large arteriovenous malformations. Each patient had fiducials surgically implanted in the outer table of the skull at the first GK treatment. These markers were imaged on orthogonal radiographs, which were scanned into the GK planning system. For the same patients, 8-10 pairs of internal landmarks were retrospectively identified on the three-dimensional time-of-flight magnetic resonance imaging studies that had been obtained for treatment. The coordinate transformation between the stereotactic frame space for subsequent treatment sessions was then determined by point matching, using four surgically embedded fiducials and then using four pairs of internal anatomic landmarks. In both cases, the transformation was ascertained by minimizing the chi-square difference between the actual and the transformed coordinates. Both transformations were then evaluated using the remaining four to six pairs of internal landmarks as the test points. Results: Averaged over all treatment sessions, the root mean square discrepancy between the coordinates of the transformed and actual test points was 1.2 ± 0.2 mm using internal landmarks and 1.7 ± 0.4 mm using the surgically implanted fiducials. Conclusion: The results of this study have shown that using internal landmarks to determine the coordinate transformation between subsequent magnetic resonance imaging scans for volume-staged GK arteriovenous malformation treatment sessions is as accurate as using surgically implanted fiducials and avoids an invasive procedure

  3. Forebrain development in fetal MRI: evaluation of anatomical landmarks before gestational week 27

    International Nuclear Information System (INIS)

    Forebrain malformations include some of the most severe developmental anomalies and require early diagnosis. The proof of normal or abnormal prosencephalic development may have an influence on further management in the event of a suspected fetal malformation. The purpose of this retrospective study was to evaluate the detectability of anatomical landmarks of forebrain development using in vivo fetal magnetic resonance imaging (MRI) before gestational week (gw) 27. MRI studies of 83 singleton fetuses (gw 16-26, average ±sd: gw 22 ± 2) performed at 1.5 Tesla were assessed. T2-weighted (w) fast spin echo, T1w gradient-echo and diffusion-weighted sequences were screened for the detectability of anatomical landmarks as listed below. The interhemispheric fissure, ocular bulbs, corpus callosum, infundibulum, chiasm, septum pellucidum (SP), profile, and palate were detectable in 95%, 95%, 89%, 87%, 82%, 81%, 78%, 78% of cases. Olfactory tracts were more easily delineated than bulbs and sulci (37% versus 18% and 8%), with significantly higher detection rates in the coronal plane. The pituitary gland could be detected on T1w images in 60% with an increasing diameter with gestational age (p=0.041). The delineation of olfactory tracts (coronal plane), chiasm, SP and pituitary gland were significantly increased after week 21 (p<0.05). Pathologies were found in 28% of cases. This study provides detection rates for anatomical landmarks of forebrain development with fetal MRI before gw 27. Several anatomical structures are readily detectable with routine fetal MRI sequences; thus, if these landmarks are not delineable, it should raise the suspicion of a pathology. Recommendations regarding favorable sequences/planes are provided. (orig.)

  4. Fully automatic detection of corresponding anatomical landmarks in volume scans of different respiratory state

    International Nuclear Information System (INIS)

    A method is described which provides fully automatic detection of corresponding anatomical landmarks in volume scans taken at different respiratory states. The resulting control points are needed for creating a volumetric deformation model for motion compensation in radiotherapy. Prior to treatment two CT volumes are taken, one scan during inhalation, one during exhalation. These scans and the detected control point pairs are taken as input for creating the four-dimensional model by using thin-plate splines

  5. Forebrain development in fetal MRI: evaluation of anatomical landmarks before gestational week 27

    Energy Technology Data Exchange (ETDEWEB)

    Schmook, Maria T.; Weber, Michael; Kasprian, Gregor; Nemec, Stefan; Prayer, Daniela [Medical University of Vienna, Department of Radiology/Division of Neuro- and Musculoskeletal Radiology, Vienna (Austria); Brugger, Peter C. [Medical University of Vienna, Integrative Morphology Group, Center for Anatomy and Cell Biology, Vienna (Austria); Krampl-Bettelheim, Elisabeth [Department of Obstetrics and Gynecology / Division of Obstetrics and Feto-maternal Medicine, Vienna (Austria)

    2010-06-15

    Forebrain malformations include some of the most severe developmental anomalies and require early diagnosis. The proof of normal or abnormal prosencephalic development may have an influence on further management in the event of a suspected fetal malformation. The purpose of this retrospective study was to evaluate the detectability of anatomical landmarks of forebrain development using in vivo fetal magnetic resonance imaging (MRI) before gestational week (gw) 27. MRI studies of 83 singleton fetuses (gw 16-26, average {+-}sd: gw 22 {+-} 2) performed at 1.5 Tesla were assessed. T2-weighted (w) fast spin echo, T1w gradient-echo and diffusion-weighted sequences were screened for the detectability of anatomical landmarks as listed below. The interhemispheric fissure, ocular bulbs, corpus callosum, infundibulum, chiasm, septum pellucidum (SP), profile, and palate were detectable in 95%, 95%, 89%, 87%, 82%, 81%, 78%, 78% of cases. Olfactory tracts were more easily delineated than bulbs and sulci (37% versus 18% and 8%), with significantly higher detection rates in the coronal plane. The pituitary gland could be detected on T1w images in 60% with an increasing diameter with gestational age (p=0.041). The delineation of olfactory tracts (coronal plane), chiasm, SP and pituitary gland were significantly increased after week 21 (p<0.05). Pathologies were found in 28% of cases. This study provides detection rates for anatomical landmarks of forebrain development with fetal MRI before gw 27. Several anatomical structures are readily detectable with routine fetal MRI sequences; thus, if these landmarks are not delineable, it should raise the suspicion of a pathology. Recommendations regarding favorable sequences/planes are provided. (orig.)

  6. Impact of different anatomical landmarks on registration in imaging-guided radiation for lung cancer

    International Nuclear Information System (INIS)

    Objective: To evaluate the impact of different anatomical landmarks on registration in imaging-guided radiation (IGRT) for lung cancer. Methods: For 20 patients with non-small cell lung cancer receiving stereotactic body radiotherapy (SBRT) in Fudan University Cancer Hospital, 100 frames of kilo-voltage cone-beam computed tomography scanning were evaluated in this study. The spine, carina and tumor were selected as landmarks for registration, respectively. Results of registration using different landmarks were documented and compared. Results: The average set-up errors in the left-right, superior inferior and anterior-posterior directions were -0.08 cm ±0.32 cm, -0.16 cm ±0.45 cm and 0.06 cm ±0.23 cm with the spine for registration; 0.06 cm ±0.34 cm, -0.13 cm ±0.45 cm and -0.02 cm±0.23 cm with the carina; and -0.17 cm ±0.25 cm, 0.03 cm ±0.47 cm and 0.15 cm ±0.38 cm with tumor. The registration results between using the carina and tumor as landmarks were statistically significant different (q=4.61, P=0.002; q = 2.23 , P=0.118; q=3.44, P=0.017). The registration results were equal when using the spine and tumor as landmarks (q =1.85, P = 0.195; q = 2.54, P = 0.075; q = 1.89, P=0.185), as well as using the carina and tumor as landmarks (q=2.76, P=0.054; q=0.31, P=0.826; q=1.55, P=0.276). Conclusions: For early stage lung cancer, the spine and tumor can be used equally as registration landmarks in imaging-guided SBRT. The carina is not suggested for its poor reproducible position. (authors)

  7. Anatomic Landmarks for Localization of the Vertical Segment of Facial Nerve on Multislice CT Multiplanar Reconstruction Images.

    Science.gov (United States)

    Ren, Bichen; Bai, Peng; Li, Tenghai; Guo, Hanfei; Wang, Bin; Zhang, Siwen; Cheng, Kailiang; Li, Youqiong

    2015-10-01

    The facial nerve decompression via mastoid is simple and easy to expose the vertical segment of the facial nerve (VFN). The objective of this study was to find out the relationship between the VFN and anatomic landmarks to facilitate prediction of the location of VFN during facial nerve decompression. The different landmarks were cochlear window (CW), oval window (OW), promontorium tympani (PT), and mastoid antrum (MA). Parameters of 140 patients (280 observations) with healthy middle ears were measured on high-resolution spiral multislice computed tomographic multiplanar reconstruction (MPR) images that were parallel to the base plane. The data gained were analyzed by statistical method and were also analyzed with respect to side and gender. The angle between orientation of VFN to the CW of the longest distance and horizontal axis was larger on the left side than that of the right (P facial nerve decompression through mastoid. PMID:26468809

  8. The secondary lobe as anatomic landmark for different pulmonary diseases

    International Nuclear Information System (INIS)

    The objective of this paper is to present the spectrum of pathological findings in the pulmonary parenchyma, based on the knowledge of the secondary lobe and its components. The evaluation was made using high-resolution computed tomography (HRCT) and compared with the histopathological findings. By definition, the secondary lobe is the small portion of pulmonary tissue separated by septa of connective tissue and supplied by 2-5 or more terminal bronchioles according to their central or peripheral location. Different disorders may become evident as a consequence of : 1) Bronchiolar obstruction (transient or definitive); 2) Intra-alveolar or wall involvement; 3) Involvement of the support tissue; 4) Involvement of the vascular or lymphatic structures. The etiology may be idiopathic, infectious, due to inhalation, neoplastic, allergic, due to collagen diseases, secondary to drug administration and/or post-transplantation. The evaluation of the secondary lobe components, with fine section HRCT, is the dynamic method of choice for the characterisation of pulmonary diseases, and allows to perform earlier and more precise differential diagnoses, when correlated with the clinical findings. The addition of sections during expiration to the routine study is paramount to underscore perfusion disturbances, which may remain undiagnosed during deep inspiration. The goal of this study is to review some of these disorders in which HRCT may be very useful and to correlate our observations with the histopathological findings. (author)

  9. Software Designation to Assess the Proximity of Different Facial Anatomic Landmarks to Midlines of the Mouth and Face

    Directory of Open Access Journals (Sweden)

    Moshkelgosha V

    2014-12-01

    Full Text Available Statement of Problem: Recognition and determination of facial and dental midline is important in dentistry. Currently, there are no verifiable guidelines that direct the choice of specific anatomic landmarks to determine the midline of the face or mouth. Objectives: The purpose of this study was to determine which of facial anatomic landmarks is closest to the midline of the face as well as that of the mouth. Materials and Methods: Frontal full-face digital images of 92 subjects (men and women age range: 20-30 years in smile were taken under standardized conditions; commonly used anatomic landmarks, nasion, tip of the nose, and tip of the philtrum were digitized on the images of subjects and aesthetic analyzer software used for midline analysis using Esthetic Frame. Deviations from the midlines of the face and mouth were measured for the 3 clinical landmarks; the existing dental midline was considered as the fourth landmark. The entire process of midline analysis was done by a single observer and repeated twice. Reliability analysis and 1-sample t- tests were conducted. Results: The Intra-class correlation coefficients (ICCs for reliability analysis of RFV and RCV measures made two times revealed that the reliabilities were all acceptable. The results indicated that each of the 4 landmarks deviated uniquely and significantly (P<.001 from the midlines of the face as well as mouth in both males and females. Conclusions: There was a significant difference between the mean ratios of the chosen anatomic landmarks and the midlines of the face and mouth. The hierarchy of anatomic landmarks closest to the midline of the face is: (1 midline of the commissures, (2 nasion , (3 tip of philtrum,(4 dental midline, and (5 tip ofthe nose. The closest anatomic landmarks to the mouth midline are: (1 tip of philtrum, (2 dental midline, (3 tip of nose, and (4 nasion.

  10. The accuracy of image registration for the brain and the nasopharynx using external anatomical landmarks

    International Nuclear Information System (INIS)

    We investigated the accuracy of 3D image registration using markers that are repeatedly applied to external anatomical landmarks on the head. The purpose of this study is to establish a lower limit of the errors that would occur in, for instance, MRI-SPECT matching, which in some situations can only be achieved using external landmarks. Marker matching was compared with (single-modality) volume matching for 20 MRI scans. The results were compared with a published expression for the target registration error (TRE) which gives the 3D distribution of the mismatch between both scans. It was found that the main error source is reapplying the external markers on the anatomical landmarks. The published expression describes the relative distribution of the TRE in space well, but tends to underestimate the actual registration error. This deviation is due to anisotropy in the error distribution of the marker position (errors in the direction perpendicular to the skin surface are in general much smaller than errors in other directions). A simulation of marker matching with anisotropy in the errors confirmed this finding. With four reapplied markers, the TRE is 6 mm or smaller in most regions of the head. (author)

  11. Optimization and evaluation of landmark-based image correlation

    International Nuclear Information System (INIS)

    Image correlation methods enable the complementary use of information from different medical images of a patient. There is a need for correlation techniques requiring no preparation in advance. The authors have developed two correlation methods, both based on three or more anatomical or artificial landmarks, to be defined in corresponding image data sets. These methods have been evaluated with phantom data as well as with patient data. The authors have improved these correlation methods by using more landmarks and special selection criteria. They are applicable to all medical tomograms and to x-ray pictures taken under stereotactical conditions. The results obtained have error ranges in the order of the three-dimensional image resolution. (author)

  12. Automatic recognition of surface landmarks of anatomical structures of back and posture

    Science.gov (United States)

    Micho?ski, Jakub; Glinkowski, Wojciech; Witkowski, Marcin; Sitnik, Robert

    2012-05-01

    Faulty postures, scoliosis and sagittal plane deformities should be detected as early as possible to apply preventive and treatment measures against major clinical consequences. To support documentation of the severity of deformity and diminish x-ray exposures, several solutions utilizing analysis of back surface topography data were introduced. A novel approach to automatic recognition and localization of anatomical landmarks of the human back is presented that may provide more repeatable results and speed up the whole procedure. The algorithm was designed as a two-step process involving a statistical model built upon expert knowledge and analysis of three-dimensional back surface shape data. Voronoi diagram is used to connect mean geometric relations, which provide a first approximation of the positions, with surface curvature distribution, which further guides the recognition process and gives final locations of landmarks. Positions obtained using the developed algorithms are validated with respect to accuracy of manual landmark indication by experts. Preliminary validation proved that the landmarks were localized correctly, with accuracy depending mostly on the characteristics of a given structure. It was concluded that recognition should mainly take into account the shape of the back surface, putting as little emphasis on the statistical approximation as possible.

  13. Efficacy and costs comparison of anatomical landmarks and ultrasonic guidance during brachial plexus block

    International Nuclear Information System (INIS)

    Objective: To compare the efficacy and costs of brachial plexus block (BPB) guided by ultrasound with that used anatomical landmarks. Methods: Eighty ASA ? or ? patients scheduled for upper extremity operation were prospectively randomized into 2 groups: Group A (n=40, BPB using anatomical landmarks) and group U (n=40, BPB guided in real time by a two-dimensional ultrasonic image). The time spent on performing the block, the onset time and duration of analgesia were measured. The proportion of successful and excellent blocks and the incidence of complications were assessed. The cost of anesthetic and the total cost of anesthesia were recorded. Results: Compared with group A, in group U the time spent on performing the block and the onset time of analgesia were significantly shorter, the duration of analgesia was significantly longer, the excellence rate of block was significantly higher (all P<0.05). 95.0% of patients in group A and 97.5% of patients in group U had a successful block (P >0.05). Four patients in group A and two patients in group U had occurred complications (P>0.05). The cost of anesthetic in group U was significantly less than in group A (P<0.01). There was no significant difference in the total cost of anesthesia between the two groups (P>0.05). Conclusion: BPB guided by ultrasound provides better block with more rapid performance and longer duration of analgesia as compared with that used anatomical landmarks. Ultrasound-guided BPB is suitable for upper extremity operation and lowers the anesthetic cost. (authors)

  14. Landmark-based pedestrian navigation

    OpenAIRE

    Basiri, Anahid; Winstanley, Adam; Amirian, Pouria

    2013-01-01

    Car navigation has become one of the most widely used examples of Location-Based Services (LBSs). However current car navigation systems are not fully suitable for the navigational needs of pedestrians mainly because walkers are not as restricted as car drivers. Pedestrians can easily go into a building or underground to get to their destination where GPS signals are unavailable. Seamless indoor and outdoor navigation is one of the most important features which should be handle...

  15. Pressure distribution on the anatomic landmarks of the knee and the effect of kneepads.

    Science.gov (United States)

    Porter, William L; Mayton, Alan G; Moore, Susan M

    2010-12-01

    This study examines stress transmitted to anatomic landmarks of the knee (patella, combined patella tendon and tibial tubercle) while in static kneeling postures without kneepads and while wearing two kneepads commonly worn in the mining industry. Ten subjects (7 male, 3 female) simulated postures utilized in low-seam mines: kneeling in full flexion; kneeling at 90° of knee flexion; and kneeling on one knee while in one of three kneepad states (no kneepads, non-articulated kneepads, and articulated kneepads). For each posture, peak and mean pressure on the anatomic landmarks of the knee were obtained. The majority of the pressure was found to be transmitted to the knee via the combined patellar tendon and tibial tubercle rather than through the patella. While the kneepads tested decreased the maximum pressure experienced at the combined patellar tendon and tibial tubercle, peak pressures of greater than 25 psi were still experienced over structures commonly injured in mining (e.g. bursa sac - bursitis/Miner's Knee). The major conclusion of this study is that novel kneepad designs that redistribute the stresses at the knee across a greater surface area and to other regions of the leg away from key structures of the knee are needed. PMID:20554268

  16. Surgical Anatomical Landmarks of the Thoracolumbar Vertebral Column on Magnetic Resonance Imaging in Dogs.

    Science.gov (United States)

    Yeamans, C L; Haley, A; Gutierrez-Quintana, R; Penderis, J

    2016-04-01

    Magnetic resonance imaging (MRI) in veterinary medicine profoundly improved spinal cord disease investigation in canine patients. We aimed to further describe the anatomical landmarks of the thoracolumbar junction in sagittal MRI sequences. MRI studies from 90 dogs were reviewed retrospectively, representing a broad cross section of breeds and body weights. The ratio of the distance from the dorsal aspect of the vertebral canal to the dorsal aspect of the transverse process or rib articulation relative to the length of L2 vertebra was determined for T12, T13, L1 and L2 vertebrae. A statistically significant difference was noted with the transverse processes being more ventrally located than the cranial fovea costalis. The lumbar transverse processes and rib articulations dramatically varied in shape, being oval or round, respectively. The sagittal image at the level of the lateral margin of the articular facet joint proved to be the most consistent for review of these structures. PMID:26105110

  17. Methods for determining hip and lumbosacral joint centers in a seated position from external anatomical landmarks.

    Science.gov (United States)

    Peng, Junfeng; Panda, Jules; Van Sint Jan, Serge; Wang, Xuguang

    2015-01-21

    A global coordinate system (GCS) method is proposed to estimate hip and lumbosacral joint centers (HJC and LSJC) from at least three distances between joint center of interest and target anatomic landmarks (ALs). The distances from HJC and LSJC to relevant pelvis and femur ALs were analyzed with respect to usual pelvis and femur scaling dimensions. Forty six pelves and related pairs of femurs from a same sample of adult specimens were examined. The corresponding regression equations were obtained. These equations can be used to estimate HJC and LSJC in conditions where a very limited number of ALs are available: for example, during seated posture analysis as performed in the automotive industry. Compared to currently existing HJC and LSJC methods from ALs, the proposed method showed better results with an average error less than 11 mm. PMID:25497377

  18. A new method to validate thoracic CT-CT deformable image registration using auto-segmented 3D anatomical landmarks

    DEFF Research Database (Denmark)

    Nielsen, Martin S; Østergaard, Lasse R; Carl, Jesper

    2015-01-01

    BACKGROUND: Deformable image registrations are prone to errors in aligning reliable anatomically features. Consequently, identification of registration inaccuracies is important. Particularly thoracic three-dimensional (3D) computed tomography (CT)-CT image registration is challenging due to lack of contrast in lung tissue. This study aims for validation of thoracic CT-CT image registration using auto-segmented anatomically landmarks. MATERIAL AND METHODS: Five lymphoma patients were CT scanned ...

  19. Evaluation of anatomic landmarks and safe zones for screw placement in the atlas via the posterior arch

    OpenAIRE

    Gebauer, Matthias; Barvencik, Florian; Briem, Daniel; Kolb, Jan P.; Seitz, Sebastian; Rueger, Johannes M.; Püschel, Klaus; Amling, Michael

    2009-01-01

    Several studies have evaluated quantitative anatomic data for direct lateral mass screw fixation. To analyze anatomic landmarks and safe zones for optimal screw placement through the posterior arc of the human atlas, morphometric parameters of 41 adult native human atlas specimens were quantitatively measured. Internal dimensions of the atlas (lateral mass, maximum and minimum intraosseous screw length), minimum height and width of the posterior arc and optimal screw insertion angles were def...

  20. Autonomous Robot Navigation based on Visual Landmarks

    DEFF Research Database (Denmark)

    Livatino, Salvatore

    2005-01-01

    update of the estimated robot position while the robot is moving. In order to make the system autonomous, both acquisition and observation of landmarks have to be carried out automatically. The thesis consequently proposes a method for learning and navigation of a working environment and it explores...... autonomous navigation and self-localization using automatically selected landmarks. The thesis investigates autonomous robot navigation and proposes a new method which benefits from the potential of the visual sensor to provide accuracy and reliability to the navigation process while relying on naturally...... system can automatically learn and store visual landmarks, and later recognize these landmarks from arbitrary positions and thus estimate robot position and heading....

  1. Anatomic landmarks of fluoroscopy guided puncture of the pulseless femoral artery

    International Nuclear Information System (INIS)

    We wanted to improve puncturing the pulseless femoral artery by evaluating the anatomic landmarks that suggest the course of the femoral artery on fluoroscopy. We analyzed 37 hemipelvis spot images that were centered on the arterial sheath after puncture of the femoral artery. The inguinal angles were measured between the inguinal line connecting the anterior superior iliac spine and the symphysis pubis, and the line of the arterial sheath. Inguinal ligament ratios were measured as the distance from the symphysis pubis to the arterial sheath to the length of the inguinal ligament on the inguinal line. The femoral head ratios were measured as the distance from the medial margin of the femur head to the arterial sheath to the transverse length of the femur head. The mean inguinal angle was 66.5 and the mean inguinal ligament ratio was 0.42 (± 0.03). The mean femoral head ratio was 0.08 (± 0.18). In comparing the men and women, there was no significant difference in the inguinal angle and the femoral head ratio, but the inguinal distance ratio was larger in women (men: 0.41 ± 0.033, women: 0.44 ± 0.031, ? < 0.05). The femoral artery generally courses just lateral to the medial margin of the femur head (femoral head ratio: 0.08) and the medial 40% of the inguinal ligament (inguinal ligament ratio: 0.42). So, consideration of these relations may be helpful for puncturing the pulseless femoral artery

  2. Analysis of anatomical landmarks of the mandibular interforaminal region using CBCT in a Brazilian population

    Scientific Electronic Library Online (English)

    Paloma Rodrigues, Genú; Ricardo José de Holanda, Vasconcellos; Bruna Paloma de, Oliveira; Bruna Caroline Gonçalves de, Vasconcelos; Nádia Cristina da Cruz, Delgado.

    2014-12-01

    Full Text Available Aim: To evaluate the position, presence, appearance and extent of various anatomical landmarks in the mandibular interforaminal region of Brazilian patients using cone-beam computed tomography (CBCT). Methods: A total of 142 CBCT examinations were analyzed to determine the most common location of th [...] e mental foramen (MF), the presence and extent of the anterior loop (AL) of the inferior alveolar nerve, and the appearance and length of the incisive canal (IC). The presence of sexual dimorphism and differences with relation to the left and right sides were also evaluated. Results: Most of the MF (45.5%) was located below the second premolar. The AL and the IC were observed in 18.9 and 96.5% of the images respectively. The average length of AL and IC was 3.14±1.25 mm and 13.68±5.94 mm respectively. No significant differences (p>0.05) between genders or left and right sides were observed for all evaluated parameters. Conclusions: The most common location of the MF, the high rate of visualization of the IC and the occasional presence of AL in the studied Brazilian population demonstrate the importance of using three-dimensional images of the mandibular anterior region, allowing proper surgical planning and preventing injury to the neurovascular bundle.

  3. The mid-sternal length, a practical anatomical landmark for optimal positioning of long-term central venous catheters

    OpenAIRE

    Salimi, Fereshte; Imani, Mohammad Reza; Ghasemi, Navab; Keshavarzian, Amir; Jazi, Amir Hosein Davarpanah

    2013-01-01

    Background: Long-term tunneled catheters are used for the hemodialysis or chemotherapy in many patients. Proper placement of the catheter tip could reduce early and late catheter related complications. Aim of the present study was to evaluate a new formula for proper placement of tunneled hemodialysis or infusion port device by using an external anatomic landmark. Materials and Methods: A total of 64 adult patients undergoing elective placement of tunneled Central Venous Catheter (CVC) requir...

  4. Anatomical landmarks and skin markers are not reliable for accurate labeling of thoracic vertebrae on MRI

    Energy Technology Data Exchange (ETDEWEB)

    Shabshin, Nogah (Dept. of Diagnostic Imaging, Chaim Sheba Medical Center, Tel-HaShomer (Israel)), e-mail: shabshin@gmail.com; Schweitzer, Mark E. (Dept. of Diagnostic Imaging, Ottawa Hospital and Univ. of Ottawa, Ottawa (Canada)); Carrino, John A. (Dept. of Radiology, Johns Hopkins Univ. School of Medicine, Baltimore, MD (United States))

    2010-11-15

    Background: Numbering of the thoracic spine on MRI can be tedious if C2 and L5-S1 are not included and may lead to errors in lesion level. Purpose: To determine whether anatomic landmarks or external markers are reliable as an aid for accurate numbering of thoracic vertebrae on MRI. Material and Methods: Sixty-seven thoracic spine MR studies of 67 patients (30 males, 37 females, age range 18-83 years) were studied, composed of 52 consecutive MR studies and an additional 15 MRI in which vitamin E markers were placed over the skin. In the 52 thoracic MR examinations potential numbering aids such as the level of the sternal apex, pulmonary artery, aortic arch, and osseous or disc abnormalities were numbered on both cervical localizer (standard of reference) and thoracic sagittal images. The additional 15 examinations in which vitamin E markers were placed over the skin were evaluated for consistency in the level of the markers on different sequences in the same exam. Results: The sternal apex level ranged from T2 to T5 [T3 in 28/51 patients (55%), T2 in 10/51 (20%)]. The aortic arch level ranged from T2 to T4 [T4 in 18/48 (38%) and T3 in 17 (35%)]. Pulmonary artery level ranged from T4 to T6-7 disc [T5 in 20/52 patients (38%) and T6 in 14/52 (27%)]. In 3 of 12 patients who had abnormalities in a vertebral body or disc as definite point reference, the non-localizer image mislabelled the level. In 11/15 (73%) patients with vitamin E markers that were placed over the upper thoracic spine, the results showed consistency in the level of the markers in relation to the reference points or consistent inter-marker gap between the sequences. Conclusion: There are only two reliable ways to accurately define the levels if no landmarking feature is available on the magnet. The first is by including C2 in the thoracic sequence of a diagnostic quality, and the second is by using an abnormality in the discs or vertebral bodies as a point of reference

  5. Anatomical landmarks and skin markers are not reliable for accurate labeling of thoracic vertebrae on MRI

    International Nuclear Information System (INIS)

    Background: Numbering of the thoracic spine on MRI can be tedious if C2 and L5-S1 are not included and may lead to errors in lesion level. Purpose: To determine whether anatomic landmarks or external markers are reliable as an aid for accurate numbering of thoracic vertebrae on MRI. Material and Methods: Sixty-seven thoracic spine MR studies of 67 patients (30 males, 37 females, age range 18-83 years) were studied, composed of 52 consecutive MR studies and an additional 15 MRI in which vitamin E markers were placed over the skin. In the 52 thoracic MR examinations potential numbering aids such as the level of the sternal apex, pulmonary artery, aortic arch, and osseous or disc abnormalities were numbered on both cervical localizer (standard of reference) and thoracic sagittal images. The additional 15 examinations in which vitamin E markers were placed over the skin were evaluated for consistency in the level of the markers on different sequences in the same exam. Results: The sternal apex level ranged from T2 to T5 [T3 in 28/51 patients (55%), T2 in 10/51 (20%)]. The aortic arch level ranged from T2 to T4 [T4 in 18/48 (38%) and T3 in 17 (35%)]. Pulmonary artery level ranged from T4 to T6-7 disc [T5 in 20/52 patients (38%) and T6 in 14/52 (27%)]. In 3 of 12 patients who had abnormalities in a vertebral body or disc as definite point reference, the non-localizer image mislabelled the level. In 11/15 (73%) patients with vitamin E markers that were placed over the upper thoracic spine, the results showed consistency in the level of the markers in relation to the reference points or consistent inter-marker gap between the sequences. Conclusion: There are only two reliable ways to accurately define the levels if no landmarking feature is available on the magnet. The first is by including C2 in the thoracic sequence of a diagnostic quality, and the second is by using an abnormality in the discs or vertebral bodies as a point of reference

  6. A new method to validate thoracic CT-CT deformable image registration using auto-segmented 3D anatomical landmarks

    DEFF Research Database (Denmark)

    Nielsen, Martin S; Østergaard, Lasse R

    2015-01-01

    BACKGROUND: Deformable image registrations are prone to errors in aligning reliable anatomically features. Consequently, identification of registration inaccuracies is important. Particularly thoracic three-dimensional (3D) computed tomography (CT)-CT image registration is challenging due to lack of contrast in lung tissue. This study aims for validation of thoracic CT-CT image registration using auto-segmented anatomically landmarks. MATERIAL AND METHODS: Five lymphoma patients were CT scanned three times within a period of 18 months, with the initial CT defined as the reference scan. For each patient the two successive CT scans were registered to the reference CT using three different image registration algorithms (Demons, B-spline and Affine). The image registrations were evaluated using auto-segmented anatomical landmarks (bronchial branch points) and Dice Similarity Coefficients (DSC). Deviation of corresponding bronchial landmarks were used to quantify inaccuracies in respect of both misalignment and geometric location within lungs. RESULTS: The median bronchial branch point deviations were 1.6, 1.1 and 4.2 (mm) for the three tested algorithms (Demons, B-spline and Affine). The maximum deviations (> 15 mm) were found within both Demons and B-spline image registrations. In the upper part of the lungs the median deviation of 1.7 (mm) was significantly different (p 15 mm in both Demons and B-spline deformable algorithms.

  7. Content-Based Visual Landmark Search via Multimodal Hypergraph Learning.

    Science.gov (United States)

    Zhu, Lei; Shen, Jialie; Jin, Hai; Zheng, Ran; Xie, Liang

    2015-12-01

    While content-based landmark image search has recently received a lot of attention and became a very active domain, it still remains a challenging problem. Among the various reasons, high diverse visual content is the most significant one. It is common that for the same landmark, images with a wide range of visual appearances can be found from different sources and different landmarks may share very similar sets of images. As a consequence, it is very hard to accurately estimate the similarities between the landmarks purely based on single type of visual feature. Moreover, the relationships between landmark images can be very complex and how to develop an effective modeling scheme to characterize the associations still remains an open question. Motivated by these concerns, we propose multimodal hypergraph (MMHG) to characterize the complex associations between landmark images. In MMHG, images are modeled as independent vertices and hyperedges contain several vertices corresponding to particular views. Multiple hypergraphs are firstly constructed independently based on different visual modalities to describe the hidden high-order relations from different aspects. Then, they are integrated together to involve discriminative information from heterogeneous sources. We also propose a novel content-based visual landmark search system based on MMHG to facilitate effective search. Distinguished from the existing approaches, we design a unified computational module to support query-specific combination weight learning. An extensive experiment study on a large-scale test collection demonstrates the effectiveness of our scheme over state-of-the-art approaches. PMID:25576590

  8. Endoscopic Orientation of the Parasellar Region in Sphenoid Sinus with Ill-Defined Bony Landmarks: An Anatomic Study

    OpenAIRE

    Amin, Sameh M.; Ashraf Y. Nasr; Hamid A. Saleh; Foad, Mohamed M.; Herzallah, Islam R.

    2010-01-01

    The sphenoid bony landmarks are important for endoscopic orientation in skull base surgery but show a wide range of variations. We aimed to describe an instructional model for the endoscopic parasellar anatomy in sphenoid sinuses with ill-defined bony landmarks. Five preserved injected cadaveric heads and four sides of dry skulls were studied endoscopically via transethmoid, transsphenoidal approach. The parasellar region was exposed by drilling along the maxillary nerve (V2) canal [the lengt...

  9. Evaluation and Comparison of Anatomical Landmark Detection Methods for Cephalometric X-Ray Images: A Grand Challenge.

    Science.gov (United States)

    Wang, Ching-Wei; Huang, Cheng-Ta; Hsieh, Meng-Che; Li, Chung-Hsing; Chang, Sheng-Wei; Li, Wei-Cheng; Vandaele, Rémy; Marée, Raphaël; Jodogne, Sébastien; Geurts, Pierre; Chen, Cheng; Zheng, Guoyan; Chu, Chengwen; Mirzaalian, Hengameh; Hamarneh, Ghassan; Vrtovec, Tomaz; Ibragimov, Bulat

    2015-09-01

    Cephalometric analysis is an essential clinical and research tool in orthodontics for the orthodontic analysis and treatment planning. This paper presents the evaluation of the methods submitted to the Automatic Cephalometric X-Ray Landmark Detection Challenge, held at the IEEE International Symposium on Biomedical Imaging 2014 with an on-site competition. The challenge was set to explore and compare automatic landmark detection methods in application to cephalometric X-ray images. Methods were evaluated on a common database including cephalograms of 300 patients aged six to 60 years, collected from the Dental Department, Tri-Service General Hospital, Taiwan, and manually marked anatomical landmarks as the ground truth data, generated by two experienced medical doctors. Quantitative evaluation was performed to compare the results of a representative selection of current methods submitted to the challenge. Experimental results show that three methods are able to achieve detection rates greater than 80% using the 4 mm precision range, but only one method achieves a detection rate greater than 70% using the 2 mm precision range, which is the acceptable precision range in clinical practice. The study provides insights into the performance of different landmark detection approaches under real-world conditions and highlights achievements and limitations of current image analysis techniques. PMID:25794388

  10. An analysis of anatomic landmark mobility and setup errors in radiotherapy for lung cancer

    International Nuclear Information System (INIS)

    Purpose: To identify visible structures in the thorax which exhibit little internal motion during irradiation and, to determine random and systematic setup deviations in lung cancer patients with the use of these structures. Methods: Ten patients with lung cancer were set up in the supine position, and aligned using lasers. No immobilization devices were used. With an electronic portal imaging device (Siemens Beam ViewPLUS), 12 sequential images (exposure 0.54 sec.; processing time 1.5 sec.) were obtained during a single fraction of radiotherapy. These 'movie loops' were generated for the A-P fields during each of 3-5 fractions. In order to determine the mobility of internal structures during each fraction, visible structures such as the trachea, carina, the upper chest wall, aortic arch, clavicle and paraspinal line were contoured manually in each image and matched with the first image of the corresponding movie loop by means of a cross-correlation algorithm. Translations in the cranial and lateral directions and in-plane rotations were determined for each structure separately. As the reference image represents a random position, relative movements were determined by comparing the translations and rotation for every image to the calculated means per movie-loop. Standard deviations of the relative movements were determined for each structure and each patient. Patient setup was evaluated for 15 patients with lung cancer. Setup was not corrected at any time during the treatment. The electronic portal images of each fraction were matched with the digitized simulator films by using a combination of the structures which had been determined to be relatively stable in the infra-fractional analysis. Results: In the infra-fractional analysis 120 to 380 matches were made per structure (a total of 1400). The standard deviation (SD) of translations in the lateral direction was small (?1 mm) for the trachea, thoracic wall, paraspinal line and aortic arch. This was also the case for the SD of the translations in the cranial direction of the clavicle, aortic arch and upper thoracic wall. The carina was found to be relatively mobile (up to 6 mm) in both directions. The SD for in-plane rotations was negligible (<0.5 deg.) for all structures. The interpatient variation was very small (SD < 0.5 mm). In a preliminary analysis of patient setup, the random errors for translations are 2.0 mm in the lateral direction and 2.4 mm in the cranial direction (1 SD). The standard deviations of systematic errors are about 3 mm in both directions. In plane rotations were found to be negligible. Conclusions: We have identified a number of structures which exhibit little internal motion in the frontal plane, and recommend that a combination of these structures be used as anatomic landmarks for setup verification during radiotherapy of thoracic tumors. Preliminary results indicate that setup errors of patients with lung cancer in our center appear to be acceptable, even though no specific immobilization devices were used

  11. Adaptive Landmark-Based Navigation System Using Learning Techniques

    DEFF Research Database (Denmark)

    Zeidan, Bassel; Dasgupta, Sakyasingha

    2014-01-01

    The goal-directed navigational ability of animals is an essential prerequisite for them to survive. They can learn to navigate to a distal goal in a complex environment. During this long-distance navigation, they exploit environmental features, like landmarks, to guide them towards their goal. Inspired by this, we develop an adaptive landmark-based navigation system based on sequential reinforcement learning. In addition, correlation-based learning is also integrated into the system to improve learning performance. The proposed system has been applied to simulated simple wheeled and more complex hexapod robots. As a result, it allows the robots to successfully learn to navigate to distal goals in complex environments.

  12. Opacification of tympanic membrane: As an anatomic landmark of oto-radiology

    International Nuclear Information System (INIS)

    Opacification of tympanic membrane was done by attachment of a cotton patch soaked with contrast media through external meatus. Detailed evaluation of fine structures in middle ear of normal adult is easily done after opacification of tympanic membrane. It was believed that opacified tympanic membrane would be an useful landmark for early detection of cholesteatoma and a good marker also in tomography of temporal bone.

  13. Is the omega sign a reliable landmark for the neurosurgical team? An anatomical study about the central sulcus region.

    Science.gov (United States)

    Rodrigues, Thiago; Rodrigues, Mariana; Paz, Daniel; Costa, Marcos Devanir; Santos, Bruno; Braga, Vinicius; Paiva Neto, Manoel de; Centeno, Ricardo; Cavalheiro, Sergio; Chaddad-Neto, Feres

    2015-11-01

    The central sulcus region is an eloquent area situated between the frontal and parietal lobes. During neurosurgical procedures, it is sometimes difficult to understand the cortical anatomy of this region.Objective Find alternative ways to anatomically navigate in this region during neurosurgical procedures.Method We analyzed eighty two human hemispheres using a surgical microscope and completed a review of the literature about central sulcus region.Results In 68/82 hemispheres, the central sulcus did not reach the posterior ramus of the lateral sulcus. A knob on the second curve of the precentral gyrus was reliably identified in only 64/82 hemispheres.Conclusion The morphometric data presented in this article can be useful as supplementary method to identify the central sulcus region landmarks. PMID:26517217

  14. Is the omega sign a reliable landmark for the neurosurgical team? An anatomical study about the central sulcus region

    Directory of Open Access Journals (Sweden)

    Thiago Rodrigues

    2015-11-01

    Full Text Available ABSTRACTThe central sulcus region is an eloquent area situated between the frontal and parietal lobes. During neurosurgical procedures, it is sometimes difficult to understand the cortical anatomy of this region.Objective Find alternative ways to anatomically navigate in this region during neurosurgical procedures.Method We analyzed eighty two human hemispheres using a surgical microscope and completed a review of the literature about central sulcus region.Results In 68/82 hemispheres, the central sulcus did not reach the posterior ramus of the lateral sulcus. A knob on the second curve of the precentral gyrus was reliably identified in only 64/82 hemispheres.Conclusion The morphometric data presented in this article can be useful as supplementary method to identify the central sulcus region landmarks.

  15. Describing Wing Geometry of Aedes Aegypti Using Landmark-Based Geometric Morphometrics

    Directory of Open Access Journals (Sweden)

    udy P. Sendaydiego

    2013-07-01

    Full Text Available Insect wing morphology has been used in many studies to describe variations among species and populations using traditional morphometrics and more recently, geometric morphometrics. This study was conducted to determine intraspecific divergence in wing shape and venation in Aedes aegypti using landmark-based geometric morphometrics. In the Philippines, Ae. aegypti has been identified as a common dengue vector species. With the increasing cases of dengue, mosquito control programs are faced with problems on vector species diversification and proper identification. Variation in wing geometry may provide relevant information on proper identification of species and in describing population diversity. In this study, the geometry of 30 wings of female Ae. Aegypti was described using 18 anatomical landmarks and subjected to Procrustes superimposition and relative warp analysis. Results of the relative warp analysis showed some intraspecific variation in the wing outline of Ae. aegypti. The observed morphological disparity in wing shape suggest a possible morphological divergence among populations of Ae. aegypti. Based from the results of the study, landmark-based geometric morphometrics is a good tool in describing quantitatively variations in wing shape of the mosquitoes.

  16. Adaptive Landmark-Based Navigation System Using Learning Techniques

    DEFF Research Database (Denmark)

    Zeidan, Bassel; Dasgupta, Sakyasingha; Wörgötter, Florentin; Manoonpong, Poramate

    . Inspired by this, we develop an adaptive landmark-based navigation system based on sequential reinforcement learning. In addition, correlation-based learning is also integrated into the system to improve learning performance. The proposed system has been applied to simulated simple wheeled and more complex......The goal-directed navigational ability of animals is an essential prerequisite for them to survive. They can learn to navigate to a distal goal in a complex environment. During this long-distance navigation, they exploit environmental features, like landmarks, to guide them towards their goal...... hexapod robots. As a result, it allows the robots to successfully learn to navigate to distal goals in complex environments....

  17. Neural Network Based Sensory Fusion for Landmark Detection

    Science.gov (United States)

    Kumbla, Kishan -K.; Akbarzadeh, Mohammad R.

    1997-01-01

    NASA is planning to send numerous unmanned planetary missions to explore the space. This requires autonomous robotic vehicles which can navigate in an unstructured, unknown, and uncertain environment. Landmark based navigation is a new area of research which differs from the traditional goal-oriented navigation, where a mobile robot starts from an initial point and reaches a destination in accordance with a pre-planned path. The landmark based navigation has the advantage of allowing the robot to find its way without communication with the mission control station and without exact knowledge of its coordinates. Current algorithms based on landmark navigation however pose several constraints. First, they require large memories to store the images. Second, the task of comparing the images using traditional methods is computationally intensive and consequently real-time implementation is difficult. The method proposed here consists of three stages, First stage utilizes a heuristic-based algorithm to identify significant objects. The second stage utilizes a neural network (NN) to efficiently classify images of the identified objects. The third stage combines distance information with the classification results of neural networks for efficient and intelligent navigation.

  18. An analysis of anatomic landmark mobility and setup deviations in radiotherapy for lung cancer

    International Nuclear Information System (INIS)

    Purpose: To identify thoracic structures that exhibit little internal motion during irradiation and to determine setup variations in patients with lung cancer. Methods and Materials: Intrafractional images were generated with an electronic portal-imaging device from the AP fields of 10 patients, during several fractions. To determine the intrafractional mobility of thoracic structures, visible structures were contoured in every image and matched with a reference image by means of a cross-correlation algorithm. Setup variations were determined by comparing portal images with the digitized simulator films using the stable structures as landmarks. Results: Mobility was limited in the lateral direction for the trachea, thoracic wall, paraspinal line, and aortic notch, and in the craniocaudal direction for the clavicle, aortic notch, and thoracic wall. Analysis of patient setup revealed random deviations of 2.0 mm (1 SD) in the lateral direction and 2.8 mm in the craniocaudal direction, while the systematic deviations were 2.5 and 2.0 mm (1 SD) respectively. Conclusions: We have identified thoracic structures that exhibit little internal motion in the frontal plane, and recommend that these structures be used for verifying patient setup during radiotherapy. The daily variation in the setup of lung cancer patients at our center appears to be acceptable

  19. Evidence consistent with the multiple-bearings hypothesis from human virtual landmark-based navigation

    OpenAIRE

    Forloines, Martha R.; Bodily, Kent D.; Sturz, Bradley R.

    2015-01-01

    One approach to explaining the conditions under which additional landmarks will be learned or ignored relates to the nature of the information provided by the landmarks (i.e., distance versus bearings). In the current experiment, we tested the ability of such an approach to explain the search behavior of human participants in a virtual landmark-based navigation task by manipulating whether landmarks provided stable distance, stable direction, or both stable distance and stable direction infor...

  20. Infraorbital nerve block within the Pterygopalatine fossa of the horse: anatomical landmarks defined by computed tomography

    International Nuclear Information System (INIS)

    In order to provide anaesthesia of the equine maxillary cheek teeth, a local nerve block of the infraorbital nerve in the pterygopalatine fossa had been proposed, which is referred to as the 'Palatine Bone Insertion' (PBI). As several complications with this method were reported, our study was designed to recommend a modified injection technique which avoids the risk of puncturing of relevant anatomical structures. Five cadaver heads and two living horses were examined by contrast medium injections and subsequent computed tomography (CT). Spinal needles were inserted using two different insertion techniques: The above mentioned (PBI), and a modification called 'Extraperiorbital Fat Body Insertion' (EFBI). Both techniques (PBI and EFBI) provide a consistent distribution of contrast medium around the infraorbital nerve. However, only the EFBI technique is appropriate to minimize the risk of complications. This study is an example for the permanent challenge of anatomists to supply a basis for clinical and surgical procedures

  1. Referências anatômicas na cirurgia do implante auditivo de tronco cerebral Anatomical landmarks in auditory brainstem implant surgery

    Directory of Open Access Journals (Sweden)

    Rubens Vuono Brito Neto

    2005-06-01

    Full Text Available O implante auditivo de tronco cerebral é uma opção os pacientes surdos que não têm a integridade das vias auditivas preservada. A cirurgia, por sua complexidade anatômica e funcional, requer treinamento específico em laboratório de anatomia por parte do cirurgião. OBJETIVOS: Estudar a anatomia cirúrgica da cirurgia do implante auditivo de tronco cerebral. FORMA DE ESTUDO: Estudo anatômico. MATERIAL E MÉTODO: Neste estudo dissecamos cadáver fresco preparado com solução corante injetada nas artérias e veias intra-cranianas. O local de inserção do eletrodo do implante auditivo de tronco cerebral foi estudado através do acesso translabiríntico. RESULTADOS: A técnica cirúrgica utilizada para a implantação do eletrodo de tronco cerebral é semelhante à utilizada na remoção do shwannoma vestibular. O complexo de núcleo coclear, composto pelo núcleo coclear ventral e dorsal, é o local para a colocação do eletrodo. O núcleo coclear ventral é o principal núcleo de transmissão de impulsos neurais do VIII par e seus axônios formam a principal via ascendente do nervo coclear. Tanto o núcleo ventral como o dorsal não são visíveis durante a cirurgia e sua localização depende de identificação de estruturas anatômicas adjacentes. CONCLUSÃO: A região de implantação do eletrodo do implante auditivo de tronco cerebral apresenta referências anatômicas que permitem sua fácil identificação durante a cirurgia.Auditory brainstem implant (ABI is an option for deaf patients who do not have the whole auditory pathways preserved. The surgery, because of its anatomical and functional complexity, requires specific training of the surgeon in an anatomy lab. AIM: To study the surgical anatomy of the auditory brainstem implant surgery. STUDY DESIGN: Anatomic study. MATERIAL AND METHOD: In the present study, we dissected a fresh cadaver prepared with a dye solution injected into the arteries and intracranial veins. The location of the insertion of the ABI electrode was studied through translabyrinthine access. RESULTS: The surgical technique used for implanting the brainstem electrode is similar to that used in the removal of vestibular schwannoma. The cochlear nucleus complex, comprising ventral and dorsal cochlear nuclei, is the optimal electrode site. The ventral cochlear nucleus is the principal nucleus for transmission of neural impulses from the 8th pair and form the main ascending route of the cochlear nerve. Neither the ventral nor the dorsal nuclei are visible during surgery and their location depends on the identification of adjacent anatomical structures. CONCLUSION: The region for the implantation of the electrode in the auditory brainstem implant presents anatomical landmarks that allow its easy identification during surgery.

  2. Referências anatômicas na cirurgia do implante auditivo de tronco cerebral / Anatomical landmarks in auditory brainstem implant surgery

    Scientific Electronic Library Online (English)

    Rubens Vuono, Brito Neto; Ricardo Ferreira, Bento; Alexandre, Yasuda; Guilherme Carvalhal, Ribas; Aldo Junqueira, Rodrigues Jr..

    2005-06-01

    Full Text Available O implante auditivo de tronco cerebral é uma opção os pacientes surdos que não têm a integridade das vias auditivas preservada. A cirurgia, por sua complexidade anatômica e funcional, requer treinamento específico em laboratório de anatomia por parte do cirurgião. OBJETIVOS: Estudar a anatomia cirúr [...] gica da cirurgia do implante auditivo de tronco cerebral. FORMA DE ESTUDO: Estudo anatômico. MATERIAL E MÉTODO: Neste estudo dissecamos cadáver fresco preparado com solução corante injetada nas artérias e veias intra-cranianas. O local de inserção do eletrodo do implante auditivo de tronco cerebral foi estudado através do acesso translabiríntico. RESULTADOS: A técnica cirúrgica utilizada para a implantação do eletrodo de tronco cerebral é semelhante à utilizada na remoção do shwannoma vestibular. O complexo de núcleo coclear, composto pelo núcleo coclear ventral e dorsal, é o local para a colocação do eletrodo. O núcleo coclear ventral é o principal núcleo de transmissão de impulsos neurais do VIII par e seus axônios formam a principal via ascendente do nervo coclear. Tanto o núcleo ventral como o dorsal não são visíveis durante a cirurgia e sua localização depende de identificação de estruturas anatômicas adjacentes. CONCLUSÃO: A região de implantação do eletrodo do implante auditivo de tronco cerebral apresenta referências anatômicas que permitem sua fácil identificação durante a cirurgia. Abstract in english Auditory brainstem implant (ABI) is an option for deaf patients who do not have the whole auditory pathways preserved. The surgery, because of its anatomical and functional complexity, requires specific training of the surgeon in an anatomy lab. AIM: To study the surgical anatomy of the auditory bra [...] instem implant surgery. STUDY DESIGN: Anatomic study. MATERIAL AND METHOD: In the present study, we dissected a fresh cadaver prepared with a dye solution injected into the arteries and intracranial veins. The location of the insertion of the ABI electrode was studied through translabyrinthine access. RESULTS: The surgical technique used for implanting the brainstem electrode is similar to that used in the removal of vestibular schwannoma. The cochlear nucleus complex, comprising ventral and dorsal cochlear nuclei, is the optimal electrode site. The ventral cochlear nucleus is the principal nucleus for transmission of neural impulses from the 8th pair and form the main ascending route of the cochlear nerve. Neither the ventral nor the dorsal nuclei are visible during surgery and their location depends on the identification of adjacent anatomical structures. CONCLUSION: The region for the implantation of the electrode in the auditory brainstem implant presents anatomical landmarks that allow its easy identification during surgery.

  3. Magnetic resonance imaging of the femoral trochlea: evaluation of anatomical landmarks and grading articular cartilage in cadaveric knees

    International Nuclear Information System (INIS)

    The purpose of the study was to define magnetic resonance imaging (MRI) findings before and after contrast medium opacification of the knee joint in cadaveric specimens to demonstrate anatomical landmarks of the trochlear surface in relation to the neighboring structures, and to evaluate different MRI sequences in the detection of cartilage defects of the trochlear and patellar surface of the knee. The morphology and relationship of the proximal trochlear surface to the prefemoral fat of the distal femur were investigated by use of different MR sequences before and after intra-articular gadolinium administration into the knee joint in ten cadaveric knees. Anatomic sections were subsequently obtained. In addition, evaluation of the articular surface of the trochlea was performed by two independent observers. The cartilage surfaces were graded using a 2-point system, and results were compared with macroscopic findings. Of 40 cartilage surfaces evaluated, histopathologic findings showed 9 normal surfaces, 20 containing partial-thickness defects, and 11 containing full-thickness defects. Compared with macroscopic data, sensitivity of MR sequences for the two reviewers was between 17 and 90%; specificity, 75 and 100%; positive predictive value, 75 and 100%; negative predictive value, 20 and 100%, depending on patellar or trochlea lesions. Interobserver variability for the presence of disease, which was measured using the kappa statistic, was dependent on the MR sequence used between 0.243 and 0.851. Magnetic resonance imaging sequences can be used to evaluate the cartilage of the trochlear surface with less accuracy when compared with the results of grading the articular cartilage of the patella. (orig.)

  4. Magnetic resonance imaging of the femoral trochlea: evaluation of anatomical landmarks and grading articular cartilage in cadaveric knees

    Energy Technology Data Exchange (ETDEWEB)

    Muhle, Claus [Marienhospital Vechta, Department of Radiology, Vechta (Germany); Veterans Affairs Medical Center, Department of Radiology, San Diego, CA (United States); Mo Ahn, Joong [University of Iowa, Department of Radiology, Iowa, IA (United States); Trudell, Debra; Resnick, Donald [Veterans Affairs Medical Center, Department of Radiology, San Diego, CA (United States)

    2008-06-15

    The purpose of the study was to define magnetic resonance imaging (MRI) findings before and after contrast medium opacification of the knee joint in cadaveric specimens to demonstrate anatomical landmarks of the trochlear surface in relation to the neighboring structures, and to evaluate different MRI sequences in the detection of cartilage defects of the trochlear and patellar surface of the knee. The morphology and relationship of the proximal trochlear surface to the prefemoral fat of the distal femur were investigated by use of different MR sequences before and after intra-articular gadolinium administration into the knee joint in ten cadaveric knees. Anatomic sections were subsequently obtained. In addition, evaluation of the articular surface of the trochlea was performed by two independent observers. The cartilage surfaces were graded using a 2-point system, and results were compared with macroscopic findings. Of 40 cartilage surfaces evaluated, histopathologic findings showed 9 normal surfaces, 20 containing partial-thickness defects, and 11 containing full-thickness defects. Compared with macroscopic data, sensitivity of MR sequences for the two reviewers was between 17 and 90%; specificity, 75 and 100%; positive predictive value, 75 and 100%; negative predictive value, 20 and 100%, depending on patellar or trochlea lesions. Interobserver variability for the presence of disease, which was measured using the kappa statistic, was dependent on the MR sequence used between 0.243 and 0.851. Magnetic resonance imaging sequences can be used to evaluate the cartilage of the trochlear surface with less accuracy when compared with the results of grading the articular cartilage of the patella. (orig.)

  5. Retzius-sparing robot-assisted laparoscopic radical prostatectomy: Critical appraisal of the anatomic landmarks for a complete intrafascial approach.

    Science.gov (United States)

    Asimakopoulos, Anastasios D; Miano, Roberto; Galfano, Antonio; Bocciardi, Aldo Massimo; Vespasiani, Giuseppe; Spera, Enrico; Gaston, Richard

    2015-10-01

    To provide an overview of the anatomical landmarks needed to guide a retropubic (Retzius)-sparing robot-assisted laparoscopic prostatectomy (RALP), and a step-by-step description of the surgical technique that maximizes preservation of the periprostatic neural network. The anatomy of the pelvic fossae is presented, including the recto-vesical pouch (pouch of Douglas) created by the reflections of the peritoneum. The actual technique of the trans-Douglas, intrafascial nerve-sparing robotic radical prostatectomy is described. The technique allows the prostate gland to be shelled out from under the overlying detrusor apron and dorsal vascular complex (DVC-Santorini plexus), entirely avoiding the pubovesical ligaments. There is no need to control the DVC, since the line of dissection passes beneath the plexus. Three key points to ensure enhanced nerve preservation should be respected: (1) the tips of the seminal vesicles, enclosed in a "cage" of neuronal tissue; a seminal vesicle-sparing technique is therefore advised when oncologically safe; (2) the external prostate-vesicular angle; (3) the lateral surface of the prostate gland and the apex. The principles of tension and energy-free dissection should guide all the maneuvers in order to minimize neuropathy. Using robotic technology, a complete intrafascial dissection of the prostate gland can be achieved through the Douglas space, reducing surgical trauma and providing excellent functional and oncological outcomes. PMID:26194970

  6. Evaluation of polynomial image deformation for matching of 3D- abdominal MR-images using anatomical landmarks and for atlas construction

    CERN Document Server

    Kimiaei, S; Jonsson, E; Crafoord, J; Maguire, G Q

    1999-01-01

    The aim of this study is to compare and evaluate the potential usability of linear and non-linear (polynomial) 3D-warping for constructing an atlas by matching abdominal MR-images from a number of different individuals using manually picked anatomical landmarks. The significance of this study lies in the fact that it illustrates the potential to use polynomial matching at a local or organ level. This is a necessary requirement for constructing an atlas and for fine intra-patient image matching and fusion. Finally 3D-image warping using anatomical landmark for inter-patient intra-modality image co-registration and fusion was found to be a very powerful and robust method. Additionally it can be used for intra-patient inter- modality image matching.

  7. Automatic facial expression recognition based on features extracted from tracking of facial landmarks

    Science.gov (United States)

    Ghimire, Deepak; Lee, Joonwhoan

    2014-01-01

    In this paper, we present a fully automatic facial expression recognition system using support vector machines, with geometric features extracted from the tracking of facial landmarks. Facial landmark initialization and tracking is performed by using an elastic bunch graph matching algorithm. The facial expression recognition is performed based on the features extracted from the tracking of not only individual landmarks, but also pair of landmarks. The recognition accuracy on the Extended Kohn-Kanade (CK+) database shows that our proposed set of features produces better results, because it utilizes time-varying graph information, as well as the motion of individual facial landmarks.

  8. Interfraction Displacement of Primary Tumor and Involved Lymph Nodes Relative to Anatomic Landmarks in Image Guided Radiation Therapy of Locally Advanced Lung Cancer

    International Nuclear Information System (INIS)

    Purpose: To analyze primary tumor (PT) and lymph node (LN) position changes relative to each other and relative to anatomic landmarks during conventionally fractionated radiation therapy for patients with locally advanced lung cancer. Methods and Materials: In 12 patients with locally advanced non-small cell lung cancer PT, LN, carina, and 1 thoracic vertebra were manually contoured on weekly 4-dimensional fan-beam CT scans. Systematic and random interfraction displacements of all contoured structures were identified in the 3 cardinal directions, and resulting setup margins were calculated. Time trends and the effect of volume changes on displacements were analyzed. Results: Three-dimensional displacement vectors and systematic/random interfraction displacements were smaller for carina than for vertebra both for PT and LN. For PT, mean (SD) 3-dimensional displacement vectors with carina-based alignment were 7 (4) mm versus 9 (5) mm with bony anatomy (P.05). Displacements between PT and bone (P=.04) and between PT and LN (P=.01) were significantly correlated with PT volume regression. Displacements between LN and carina were correlated with LN volume change (P=.03). Conclusions: Carina-based setup results in a more reproducible PT and LN alignment than bony anatomy setup. Considering the independence of PT and LN displacement and the impact of volume regression on displacements over time, repeated CT imaging even with PT-based alignment is recommended in locally advanced disease

  9. Is peritoneal reflection the best anatomical repair landmark in experimental colorectal surgery on rats? / A reflexão peritoneal é o melhor reparo anatômico na cirurgia experimental colorretal em ratos?

    Scientific Electronic Library Online (English)

    Denise Gonçalves, Priolli; Pamela Lícia Eiras da, Silva; Adriane Moro, Betini; José Aires, Pereira; Nelson Fontana, Margarido; Carlos Augusto Real, Martinez.

    2009-12-01

    Full Text Available OBJETIVO: Validar a placa de Peyer como reparo anatômico para a cirurgia colorretal em ratos e mensurar a quantidade de colágeno em segmentos da parede cólica que contém ou não a placa de Peyer. MÉTODOS: Foi aferida a distância entre a placa de Peyer e a reflexão peritoneal em 45 ratos Wistar. O cól [...] on e o reto foram ressecados, para a quantificação do colágeno, por meio de análise de imagem assistida por computador, em regiões do cólon que continham ou não a placa de Peyer. RESULTADOS: Existe grande variação entre a distância da placa de Peyer e a reflexão peritoneal quando se consideraram os animais de ambos os gêneros como grupo único (p= 0.04), sendo a distância entre a placa e a reflexão peritoneal maior entre as fêmeas (p=0.001). Constatou-se que o segmento cólico que contém a placa de Peyer apresenta conteúdo menor de colágeno quando comparado ao segmento onde a estrutura não estava presente (p=0.02). CONCLUSÃO: A placa de Peyer pode ser indicada como reparo anatômico e no estudo da cicatrização de anastomoses colorretais em ratos, baseado nas diferentes quantidades de colágeno tecidual existente na parede cólica que contém ou não esta estrutura. Abstract in english PURPOSE: To validate Peyer's patch as an anatomical repair landmark for colorectal surgery in rats and to measure the collagen content in segments of the colon containing or not containing Peyer's patch. METHODS: The distance between Peyer's patch and the peritoneal reflection was measured in forty- [...] five Wistar rats. The colon and rectum were resected for quantification of collagen content by means of computer-assisted image analysis in regions of the colon with and without Peyer's patch. RESULTS: There was great variation in the distance between Peyer's patch and the peritoneal reflection when the male and female rats were considered as a single group (p=0.04). Comparison between the genders showed that the distance between the patch and the peritoneal reflection was greater in female than in male rats (p=0.001). The colonic segment containing Peyer's patch was observed to have lower tissue collagen content than the segment in which this structure was not present (p=0.02). CONCLUSION: Peyer's patch can be indicated as an anatomical repair landmark, and there is a need to study the healing of colorectal anastomoses in rats based on differing quantities of tissue collagen existing in the colonic wall with or without this structure.

  10. Is peritoneal reflection the best anatomical repair landmark in experimental colorectal surgery on rats? A reflexão peritoneal é o melhor reparo anatômico na cirurgia experimental colorretal em ratos?

    Directory of Open Access Journals (Sweden)

    Denise Gonçalves Priolli

    2009-12-01

    Full Text Available PURPOSE: To validate Peyer's patch as an anatomical repair landmark for colorectal surgery in rats and to measure the collagen content in segments of the colon containing or not containing Peyer's patch. METHODS: The distance between Peyer's patch and the peritoneal reflection was measured in forty-five Wistar rats. The colon and rectum were resected for quantification of collagen content by means of computer-assisted image analysis in regions of the colon with and without Peyer's patch. RESULTS: There was great variation in the distance between Peyer's patch and the peritoneal reflection when the male and female rats were considered as a single group (p=0.04. Comparison between the genders showed that the distance between the patch and the peritoneal reflection was greater in female than in male rats (p=0.001. The colonic segment containing Peyer's patch was observed to have lower tissue collagen content than the segment in which this structure was not present (p=0.02. CONCLUSION: Peyer's patch can be indicated as an anatomical repair landmark, and there is a need to study the healing of colorectal anastomoses in rats based on differing quantities of tissue collagen existing in the colonic wall with or without this structure.OBJETIVO: Validar a placa de Peyer como reparo anatômico para a cirurgia colorretal em ratos e mensurar a quantidade de colágeno em segmentos da parede cólica que contém ou não a placa de Peyer. MÉTODOS: Foi aferida a distância entre a placa de Peyer e a reflexão peritoneal em 45 ratos Wistar. O cólon e o reto foram ressecados, para a quantificação do colágeno, por meio de análise de imagem assistida por computador, em regiões do cólon que continham ou não a placa de Peyer. RESULTADOS: Existe grande variação entre a distância da placa de Peyer e a reflexão peritoneal quando se consideraram os animais de ambos os gêneros como grupo único (p= 0.04, sendo a distância entre a placa e a reflexão peritoneal maior entre as fêmeas (p=0.001. Constatou-se que o segmento cólico que contém a placa de Peyer apresenta conteúdo menor de colágeno quando comparado ao segmento onde a estrutura não estava presente (p=0.02. CONCLUSÃO: A placa de Peyer pode ser indicada como reparo anatômico e no estudo da cicatrização de anastomoses colorretais em ratos, baseado nas diferentes quantidades de colágeno tecidual existente na parede cólica que contém ou não esta estrutura.

  11. The Comparison of Learning Radiographic Extraoral Anatomic Landmarks through Lecture and blended method(Computer-Assisted teaching and Lecture:An interventional Study

    Directory of Open Access Journals (Sweden)

    T ahmine Razi

    2013-05-01

    Full Text Available Introduction: One of the main problems in learning extraoral radiographic anatomic indexes is the long interval between presentation of radiology and human anatomy courses, resulting in forgetting anatomic regions. Therefore, radiographic indexes are formed as complete abstract and transient images in students’ minds; as a result, their learning and retention decrease. The aim of this study was to compare lecture with combination of computer-assisted learning and lecture of extra-oral radiographic landmarks among dental students. Methods: This interventional study was carried out in 2009 on 51 dental students of Tabriz University of Medical Sciences. Students were randomly allocated into two groups. The first group was taught through a teaching method which involved lectures in the classroom. In the second group, a CD was given to the students. The teaching was accomplished through presentation using skull. Six months after finishing the teaching, both groups took a similar test for evaluation of long term learning. The data was analyzed by SPSS 16 using U Mann-Whitney test. Results: There was no significant differences in the mean scores between the two groups in the first exam after teaching (P=0.13, yet it was significant in the second exam (regarding retention (P=0.006, and average of non-traditional teaching method group (20.89±10.23 was higher than that of lecture group (13.48±6.39. Conclusion: Based on the results, non-traditional technique of teaching was not more effective than the lecture in short-term learning but in longterm learning, non-traditional technique was more effective than the lecture.

  12. Computing Topology Preservation of RBF Transformations for Landmark-Based Image Registration

    OpenAIRE

    Cavoretto, R; De Rossi, A; Qiao, H.; Quatember, B.; Recheis, W.; Mayr, M.

    2014-01-01

    In image registration, a proper transformation should be topology preserving. Especially for landmark-based image registration, if the displacement of one landmark is larger enough than those of neighbourhood landmarks, topology violation will be occurred. This paper aim to analyse the topology preservation of some Radial Basis Functions (RBFs) which are used to model deformations in image registration. Mat\\'{e}rn functions are quite common in the statistic literature (see, ...

  13. Validation of automatic landmark identification for atlas-based segmentation for radiation treatment planning of the head-and-neck region

    Science.gov (United States)

    Leavens, Claudia; Vik, Torbjørn; Schulz, Heinrich; Allaire, Stéphane; Kim, John; Dawson, Laura; O'Sullivan, Brian; Breen, Stephen; Jaffray, David; Pekar, Vladimir

    2008-03-01

    Manual contouring of target volumes and organs at risk in radiation therapy is extremely time-consuming, in particular for treating the head-and-neck area, where a single patient treatment plan can take several hours to contour. As radiation treatment delivery moves towards adaptive treatment, the need for more efficient segmentation techniques will increase. We are developing a method for automatic model-based segmentation of the head and neck. This process can be broken down into three main steps: i) automatic landmark identification in the image dataset of interest, ii) automatic landmark-based initialization of deformable surface models to the patient image dataset, and iii) adaptation of the deformable models to the patient-specific anatomical boundaries of interest. In this paper, we focus on the validation of the first step of this method, quantifying the results of our automatic landmark identification method. We use an image atlas formed by applying thin-plate spline (TPS) interpolation to ten atlas datasets, using 27 manually identified landmarks in each atlas/training dataset. The principal variation modes returned by principal component analysis (PCA) of the landmark positions were used by an automatic registration algorithm, which sought the corresponding landmarks in the clinical dataset of interest using a controlled random search algorithm. Applying a run time of 60 seconds to the random search, a root mean square (rms) distance to the ground-truth landmark position of 9.5 +/- 0.6 mm was calculated for the identified landmarks. Automatic segmentation of the brain, mandible and brain stem, using the detected landmarks, is demonstrated.

  14. Indoor Localization System based on Artificial Landmarks and Monocular Vision

    OpenAIRE

    Costa, Paulo G.; A. Paulo Moreira; Andry Maykol G. Pinto

    2012-01-01

    This paper presents a visual localization approach well suited for the domestic and industrial environments due to its ability to provide an accurate, reliable and robust pose estimation.The mobile robot is equipped with a single camera to update their pose whenever a landmark is available on the field of view.The innovation presented by this research focus, especially, on the artificial landmark that has the ability to detect the presence of the robot, sinceboth entities communicates with ea...

  15. Interfraction Displacement of Primary Tumor and Involved Lymph Nodes Relative to Anatomic Landmarks in Image Guided Radiation Therapy of Locally Advanced Lung Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Jan, Nuzhat; Balik, Salim; Hugo, Geoffrey D. [Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia (United States); Mukhopadhyay, Nitai [Department of Biostatistics, Virginia Commonwealth University, Richmond, Virginia (United States); Weiss, Elisabeth, E-mail: eweiss@mcvh-vcu.edu [Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia (United States)

    2014-01-01

    Purpose: To analyze primary tumor (PT) and lymph node (LN) position changes relative to each other and relative to anatomic landmarks during conventionally fractionated radiation therapy for patients with locally advanced lung cancer. Methods and Materials: In 12 patients with locally advanced non-small cell lung cancer PT, LN, carina, and 1 thoracic vertebra were manually contoured on weekly 4-dimensional fan-beam CT scans. Systematic and random interfraction displacements of all contoured structures were identified in the 3 cardinal directions, and resulting setup margins were calculated. Time trends and the effect of volume changes on displacements were analyzed. Results: Three-dimensional displacement vectors and systematic/random interfraction displacements were smaller for carina than for vertebra both for PT and LN. For PT, mean (SD) 3-dimensional displacement vectors with carina-based alignment were 7 (4) mm versus 9 (5) mm with bony anatomy (P<.0001). For LN, smaller displacements were found with carina- (5 [3] mm, P<.0001) and vertebra-based (6 [3] mm, P=.002) alignment compared with using PT for setup (8 [5] mm). Primary tumor and LN displacements relative to bone and carina were independent (P>.05). Displacements between PT and bone (P=.04) and between PT and LN (P=.01) were significantly correlated with PT volume regression. Displacements between LN and carina were correlated with LN volume change (P=.03). Conclusions: Carina-based setup results in a more reproducible PT and LN alignment than bony anatomy setup. Considering the independence of PT and LN displacement and the impact of volume regression on displacements over time, repeated CT imaging even with PT-based alignment is recommended in locally advanced disease.

  16. Landmark based registration of 18F FDG PET to CT in patients with head and neck cancer: Case reports

    International Nuclear Information System (INIS)

    Previous studies have suggested that 18F-FDG PET can be of assistance in the monitoring of disease activity in patients with head and neck cancer undergoing radical radiotherapy treatment. Provided that an adequate period of time elapses between radiotherapy treatment and FDG-PET scanning, this metabolic imaging modality has distinct advantages over anatomical imaging modalities such as CT or MRI which rely largely on changes in size, contrast enhancement and radiodensity of residual mass. The distinction between radiation necrosis and residual tumour is particularly difficult with these modalities. Co-registration of anatomical images from CT or MRI with metabolic images from FDG-PET in this setting may help to locate residual tumour tissue more accurately than PET alone. THE PET scan was peformed on a Siemens 951/3t R PET scanner (6.5 mm in-plane resolution). Patients were positioned supine on the bed in the radiotherapy planning mask to hold the head and neck immobile. A three-bed transmission scan was peformed followed by an intravenous injection of 370 MBq of 18F-FDG. After a 45 min uptake period, a three-bed emission scan was performed to complete the study. Contrast enhanced CT was pedormed on a Picker PQ2000 helical CT scanner. Patients were scanned supine on the bed in the radiotherapy planning mask at a resolution of 21 line pairs/cm. Landmark based registration was used to co-register the PET mages to the CT images. The algorithm uses an analytic linear least-squares solution for a 12 parameter fit of at least 12 operator defined anatomical homologous landmarks in the two image volumes. Both the CT and PET scans include an area of the patient from the base of the brain to the lung apices, thus providing sufficient landmarks for the registration algorithm. We present two patients in whom FDG-PET and CT were used as tools in monitoring disease activity

  17. The Reproducibility of a Kinematically-Derived Axis of the Knee versus Digitized Anatomical Landmarks using a Knee Navigation System

    OpenAIRE

    Doro, Lisa Case; Hughes, Richard E.; Miller, Joshua D.; Schultz, Karl F; Hallstrom, Brian; Urquhart, Andrew G

    2008-01-01

    Component position is critical to longevity of knee arthroplasties. Femoral component rotation is typically referenced from the transepicondylar axis (TEA), the anterior-posterior (AP) axis or the posterior condylar axis. Other studies have shown high variability in locating the TEA while proposing digitization of other landmarks such as the AP axis as a less-variable reference. This study uses a navigation system to compare the reproducibility of computing a kinematically-derived, navigated ...

  18. Integrated landmark and outline-based morphometric methods efficiently distinguish species of Euglossa (Hymenoptera, Apidae, Euglossini)

    OpenAIRE

    Francoy, Tiago; Faria Franco, Fernando; Roubik, David

    2012-01-01

    Morphometric methods permit identification of insect species and are an aid for taxonomy. Quantitative wing traits were used to identify male euglossine bees. Landmark- and outline-based methods have been primarily used independently. Here, we combine the two methods using five Euglossa. Landmark-based methods correctly classified 84% and outline-based 77%, but an integrated analysis correctly classified 91% of samples. Some species presented significantly high reclassification percentages wh...

  19. Optimal reinforcement of training datasets in semi-supervised landmark-based segmentation

    Science.gov (United States)

    Ibragimov, Bulat; Likar, Boštjan; Pernuš, Franjo; Vrtovec, Tomaž

    2015-03-01

    During the last couple of decades, the development of computerized image segmentation shifted from unsupervised to supervised methods, which made segmentation results more accurate and robust. However, the main disadvantage of supervised segmentation is a need for manual image annotation that is time-consuming and subjected to human error. To reduce the need for manual annotation, we propose a novel learning approach for training dataset reinforcement in the area of landmark-based segmentation, where newly detected landmarks are optimally combined with reference landmarks from the training dataset and therefore enriches the training process. The approach is formulated as a nonlinear optimization problem, where the solution is a vector of weighting factors that measures how reliable are the detected landmarks. The detected landmarks that are found to be more reliable are included into the training procedure with higher weighting factors, whereas the detected landmarks that are found to be less reliable are included with lower weighting factors. The approach is integrated into the landmark-based game-theoretic segmentation framework and validated against the problem of lung field segmentation from chest radiographs.

  20. Vision-based Navigation Using Landmark Recognition for Unmanned Aerial Vehicles

    OpenAIRE

    Mannberg, Mikael

    2014-01-01

    This thesis describes a new approach for a vision-based positioning system for Un- manned Aerial Vehicles using a recognition method based on known, robust geo- graphic landmarks. Landmarks are used to calculate a position estimate in a global coordinate frame without requiring external signals, such as GPS. Absolute systems are of interest as they provide a redundant positioning system, allow UAVs to oper- ate when GPS-denied and can enable high-precision landings for spacecra...

  1. A class of spline functions for landmark-based image registration

    OpenAIRE

    De Rossi, Alessandra; Cavoretto, Roberto; Allasia, Giampietro

    2012-01-01

    A class of spline functions, called Lobachevsky splines, is proposed for landmark-based image registration. Analytic expressions of Lobachevsky splines and some of their properties are given, reasoning in the context of probability theory. Since these functions have simple analytic expressions and compact support, landmark-based transformations can be advantageously defined using them. Numerical results point out accuracy and stability of Lobachevsky splines, comparing them with Gaussians and...

  2. Anatomical landmarks for the localization of the greater palatine foramen--a study of 1200 head CTs, 150 dry skulls, systematic review of literature and meta-analysis.

    Science.gov (United States)

    Tomaszewska, Iwona M; Tomaszewski, Krzysztof A; Kmiotek, Elizabeth K; Pena, Iwona Z; Urbanik, Andrzej; Nowakowski, Micha?; Walocha, Jerzy A

    2014-10-01

    Accurate knowledge of greater palatine foramen (GPF) anatomy is necessary when performing a variety of anaesthesiological, dental or surgical procedures. The first aim of this study was to localize the GPF in relation to multiple anatomical landmarks. The second aim was to perform a systematic review of literature, and to conduct a meta-analysis on the subject of GPF position to aid clinicians in their practice. One-hundred and fifty dry, adult, human skulls and 1200 archived head computed tomography scans were assessed and measured in terms of GPF relation to other anatomical reference points. A systematic literature search was performed using the PubMed, Embase and Web of Science databases, and a meta-analysis on the subject of GPF relation to the maxillary molars was conducted. On average, in the Polish population, the GPF was positioned 15.9?±?1.5?mm from the midline maxillary suture (MMS), 3.0?±?1.2?mm from the alveolar ridge (AR) and 17.0?±?1.5?mm from the posterior nasal spine (PNS); 74.7% of GPF were positioned opposite the third maxillary molar (M3). Twenty-seven studies were included in the systematic review and 23 in the meta-analysis (n?=?6927 GPF). The pooled prevalence of the GPF being positioned opposite the M3 was 63.9% (95% confidence interval?=?56.6-70.9%). Concluding, the GPF is most often located opposite the M3 in the majority of the world's populations. The maxillary molars are the best landmarks for locating the GPF. In edentulous patients the most useful points for approximating the position of the GPF are the AR, MMS and PNS. This study introduces an easy and repeatable classification to reference the GPF to the maxillary molars. PMID:25131842

  3. Landmark Detection via Ann for a Web Based Autonomous Mobile Robot: Sunar

    Directory of Open Access Journals (Sweden)

    Nihat Y?lmaz

    2006-06-01

    Full Text Available In this study, a landmark detection method was developed for finding or position correction of a web based mobile robot designed and implemented for long term and regular scientific purposes. Colored numeric and alphanumeric character sticker in place of other artificial landmarks appropriate for robot is selected to be landmark for understanding of both human and robot. Statistical analysis of captured and segmented image part is used for feature vector extraction. Statistical properties of histogram, projections and image raw data are selectable components of feature vector. The feature vector is tested by previously trained multilayer perceptron feed forward neural network (ANN. For this aim, online programs required for robotic activities, image processing and neural network processes have been developed on web interface of web-robot. In this program, improved software libraries for SUNAR system are employed. Real time results and robot scenes are monitored online on web portal.

  4. Landmark-based versus ultrasound-guided ilioinguinal/iliohypogastric nerve blocks in the treatment of chronic postherniorrhaphy groin pain: a retrospective study

    Directory of Open Access Journals (Sweden)

    Trainor D

    2015-10-01

    Full Text Available Drew Trainor,1 Susan Moeschler,2 Matthew Pingree,1,2 Brian Hoelzer,2 Zhen Wang,2 William Mauck,2 Wenchun Qu1,2 1Department of Physical Medicine and Rehabilitation, 2Department of Anesthesiology, Division of Pain Medicine, Mayo Clinic, Rochester, MN, USABackground: Chronic postherniorrhaphy groin pain (CPGP is a debilitating condition, which is often refractory to conservative medical management. To our knowledge, there have been no studies directly comparing landmarked-based and ultrasound-guided approaches in this population.Objective: To compare the effectiveness of landmark-based and ultrasound-guided ilioinguinal/iliohypogastric nerve blocks in the treatment of CPGP.Study design: This is a retrospective chart review of patients who presented to our tertiary care pain medicine clinic with a diagnosis of CPGP. Inclusion criteria were the following: age >18 years, diagnosis of groin pain, and prior history of herniorrhaphy. Exclusion criteria included those who were seen for initial consultation but were lost to follow-up. Primary outcomes were 50% or greater reduction in pain on visual analog scale (VAS. Secondary outcomes were 30% or greater reduction in VAS pain score, changes in VAS pain scores, and reported complications.Results: A total of 36 patients were included in the study. Of them, 20 patients underwent the landmark-based and 16 underwent the ultrasound-guided techniques. There was no significant difference in baseline demographics. The average VAS score preinjection was 7.08 in the landmark-based and 7.0 in the ultrasound-guided groups (P=0.65. A total of 14 patients (70% in the landmark-based and eleven patients (79% in the ultrasound-guided groups experienced at least a 50% reduction in VAS scores. There was no statistically significant difference between the two groups (P=1.0, and no complications were noted. We also did not find a significant difference in terms of number of patients with 30% or greater reduction (P=0.71 and changes in VAS pain scores (P=0.64. No complications were reported in either group.Conclusion: In our study, there was no statistically significant difference between the landmark-based and ultrasound-guided groups in terms of a reduction in VAS pain scores, and no complications were noted in either group.Keywords: abdominal wall, intramuscular injections, ultrasound, anatomic landmarks

  5. Robust 3D face landmark localization based on local coordinate coding.

    Science.gov (United States)

    Song, Mingli; Tao, Dacheng; Sun, Shengpeng; Chen, Chun; Maybank, Stephen J

    2014-12-01

    In the 3D facial animation and synthesis community, input faces are usually required to be labeled by a set of landmarks for parameterization. Because of the variations in pose, expression and resolution, automatic 3D face landmark localization remains a challenge. In this paper, a novel landmark localization approach is presented. The approach is based on local coordinate coding (LCC) and consists of two stages. In the first stage, we perform nose detection, relying on the fact that the nose shape is usually invariant under the variations in the pose, expression, and resolution. Then, we use the iterative closest points algorithm to find a 3D affine transformation that aligns the input face to a reference face. In the second stage, we perform resampling to build correspondences between the input 3D face and the training faces. Then, an LCC-based localization algorithm is proposed to obtain the positions of the landmarks in the input face. Experimental results show that the proposed method is comparable to state of the art methods in terms of its robustness, flexibility, and accuracy. PMID:25296404

  6. Simulation of satellite landmark navigation on the base of optoelectronic image processing technique

    Science.gov (United States)

    Dyblenko, Sergey; Janschek, Klaus; Kisselev, Anton; Sultanov, Albert; Tchernykh, Valeri

    2005-06-01

    Hybrid optoelectronic landmark navigation is proposed as backup navigation for Low Earth Orbit satellite. Optoelectronic navigation can use earth observation camera, originally not assigned for navigation purposes. The concept of the landmark navigation system is based on the onboard optical correlator application for real time matching of the earth images and pre-recorded images of landmarks with known coordinates. The software model of image processing by optical correlator has been developed to test the system operation in simulated experiments and to estimate the expected performance. The hardware model of the joint transform optical correlator has been manufactured and tested. The model uses commercially available optoelectronic components and works with PC, which performs all digital processing and data flow control. As a result ofthe model testing, the feasibility ofthe system concept and the adequacy ofthe software model have been proved. The image processing system which calculates satellite attitude and position on the base of correlation peaks measurements has been used for simulation of optoelectronic satellite landmark navigation. In the series of simulated experiments the navigation accuracy was estimated in presence of image distortions and noise for earth observation mission.

  7. A landmark-based algorithm for automatic pattern recognition and abnormality detection

    OpenAIRE

    Huzurbazar, S.; Lee, Long; Kuang, Dongyang

    2016-01-01

    We study a class of mathematical and statistical algorithms with the aim of establishing a computer-based framework for fast and reliable automatic pattern recognition and abnormality detection. Under this framework, we propose a numerical algorithm for finding group averages where an average of a group is an estimator that is said to best represent the properties of interest of that group. A novelty of the proposed landmark-based algorithm is that the algorithm tracks information of the mome...

  8. Visual Homing in the Absence of Feature-Based Landmark Information

    Science.gov (United States)

    Gillner, Sabine; Weiss, Anja M.; Mallot, Hanspeter A.

    2008-01-01

    Despite that fact that landmarks play a prominent role in human navigation, experimental evidence on how landmarks are selected and defined by human navigators remains elusive. Indeed, the concept of a "landmark" is itself not entirely clear. In everyday language, the term landmark refers to salient, distinguishable, and usually nameable objects,…

  9. Visual Homing in the Absence of Feature-Based Landmark Information

    Science.gov (United States)

    Gillner, Sabine; Weiss, Anja M.; Mallot, Hanspeter A.

    2008-01-01

    Despite that fact that landmarks play a prominent role in human navigation, experimental evidence on how landmarks are selected and defined by human navigators remains elusive. Indeed, the concept of a "landmark" is itself not entirely clear. In everyday language, the term landmark refers to salient, distinguishable, and usually nameable objects,…

  10. Landmark-based registration using a local radial basis function transformation

    OpenAIRE

    Cavoretto, Roberto; De Rossi, Alessandra; Quatember, Bernhard

    2008-01-01

    In this paper we propose the use of a local image transformation involving radial basis functions for landmark-based registration of medical images. More precisely, we consider radial basis functions as nodal functions in the modified Shepard method. In this way we obtain an image transformation more accurate and stable than the one given by the global radial basis functions, as shown by numerical results.

  11. A landmark-based method for the geometrical 3D calibration of scanning microscopes

    OpenAIRE

    Ritter, Martin

    2007-01-01

    This thesis presents a new strategy and a spatial method for the geometric calibration of 3D measurement devices at the micro-range, based on spatial reference structures with nanometersized landmarks (nanomarkers). The new method was successfully applied for the 3D calibration of scanning probe microscopes (SPM) and confocal laser scanning microscopes (CLSM). Moreover, the spatial method was also used for the photogrammetric self-calibration of scanning electron microscopes (SEM). In order t...

  12. Can osseous landmarks in the distal medial humerus be used to identify the attachment sites of ligaments and tendons: paleopathologic-anatomic imaging study in cadavers

    International Nuclear Information System (INIS)

    To describe osseous landmarks that allow identification of the attachments of the ligaments and tendons in the distal medial aspect of the humerus. Reliable osseous landmarks in the distal medial aspect of the humerus were identified in 34 well-preserved specimens from a paleopathologic collection. These osseous landmarks were then sought in magnetic resonance (MR) images of ten cadaveric elbow specimens so that the ease of their visualization and optimal imaging plane could be assessed. To assign these osseous landmarks to specific attachments of the tendons and ligaments in the distal medial humerus, we cut the specimens in slices and photographed and examined them. Subsequently, the prevalence of these osseous landmarks as well as the attachment sites of the tendons and ligaments in this location was determined. We determined ten reliable osseous landmarks in the distal medial aspect of the humerus, their prevalence and ease of identification, and their relationship to the attachments of the tendons and ligaments at the medial distal humerus. It is possible to use osseous landmarks at the distal medial humerus to facilitate identification of the different attachments of tendons and ligaments when MR images of the elbow are assessed. (orig.)

  13. Can osseous landmarks in the distal medial humerus be used to identify the attachment sites of ligaments and tendons: paleopathologic-anatomic imaging study in cadavers

    Energy Technology Data Exchange (ETDEWEB)

    Buck, Florian M. [Veterans Administration Medical Center, Department of Radiology, San Diego, CA (United States); Institut fuer Diagnostische Radiologie, Uniklinik Balgrist, Zurich (Switzerland); Zoner, Cristiane S.; Cardoso, Fabiano; Gheno, Ramon; Nico, Marcelo A.C.; Trudell, Debra J.; Resnick, Donald [Veterans Administration Medical Center, Department of Radiology, San Diego, CA (United States); Randall, Tori D. [San Diego Museum of Man, Physical Anthropology, San Diego, CA (United States)

    2010-09-15

    To describe osseous landmarks that allow identification of the attachments of the ligaments and tendons in the distal medial aspect of the humerus. Reliable osseous landmarks in the distal medial aspect of the humerus were identified in 34 well-preserved specimens from a paleopathologic collection. These osseous landmarks were then sought in magnetic resonance (MR) images of ten cadaveric elbow specimens so that the ease of their visualization and optimal imaging plane could be assessed. To assign these osseous landmarks to specific attachments of the tendons and ligaments in the distal medial humerus, we cut the specimens in slices and photographed and examined them. Subsequently, the prevalence of these osseous landmarks as well as the attachment sites of the tendons and ligaments in this location was determined. We determined ten reliable osseous landmarks in the distal medial aspect of the humerus, their prevalence and ease of identification, and their relationship to the attachments of the tendons and ligaments at the medial distal humerus. It is possible to use osseous landmarks at the distal medial humerus to facilitate identification of the different attachments of tendons and ligaments when MR images of the elbow are assessed. (orig.)

  14. Knee joint secondary motion accuracy improved by quaternion-based optimizer with bony landmark constraints.

    Science.gov (United States)

    Wang, Hongsheng; Zheng, Naiqaun Nigel

    2010-12-01

    Skin marker-based motion analysis has been widely used in biomechanical studies and clinical applications. Unfortunately, the accuracy of knee joint secondary motions is largely limited by the nonrigidity nature of human body segments. Numerous studies have investigated the characteristics of soft tissue movement. Utilizing these characteristics, we may improve the accuracy of knee joint motion measurement. An optimizer was developed by incorporating the soft tissue movement patterns at special bony landmarks into constraint functions. Bony landmark constraints were assigned to the skin markers at femur epicondyles, tibial plateau edges, and tibial tuberosity in a motion analysis algorithm by limiting their allowed position space relative to the underlying bone. The rotation matrix was represented by quaternion, and the constrained optimization problem was solved by Fletcher's version of the Levenberg-Marquardt optimization technique. The algorithm was validated by using motion data from both skin-based markers and bone-mounted markers attached to fresh cadavers. By comparing the results with the ground truth bone motion generated from the bone-mounted markers, the new algorithm had a significantly higher accuracy (root-mean-square (RMS) error: 0.7 ± 0.1 deg in axial rotation and 0.4 ± 0.1 deg in varus-valgus) in estimating the knee joint secondary rotations than algorithms without bony landmark constraints (RMS error: 1.7 ± 0.4 deg in axial rotation and 0.7 ± 0.1 deg in varus-valgus). Also, it predicts a more accurate medial-lateral translation (RMS error: 0.4 ± 0.1 mm) than the conventional techniques (RMS error: 1.2 ± 0.2 mm). The new algorithm, using bony landmark constrains, estimates more accurate secondary rotations and medial-lateral translation of the underlying bone. PMID:21142329

  15. Midline as a landmark for the position of the superior sagittal sinus on the cranial vault: An anatomical and imaging study

    OpenAIRE

    Reis, Cassius Vinicius C.; Sebastião N.S. Gusmão; Elhadi, Ali M.; Dru, Alexander; Tazinaffo, Uédson; Zabramski, Joseph M.; Robert F Spetzler; Preul, Mark C

    2015-01-01

    Background: Craniotomies involving the midline are regular practice in neurosurgery, during which injury to the superior sagittal sinus (SSS), an uncommon yet devastating event, may occur. The midline tends to be the most common landmark used to identify the position of the SSS. In this study we examined the reliability of the midline as a landmark for the SSS. Methods: We performed bilateral craniectomies on eight cadaveric heads, preserving the coronal, sagittal, and lambdoid sutures. The w...

  16. Global localization of 3D anatomical structures by pre-filtered Hough forests and discrete optimization.

    Science.gov (United States)

    Donner, René; Menze, Bjoern H; Bischof, Horst; Langs, Georg

    2013-12-01

    The accurate localization of anatomical landmarks is a challenging task, often solved by domain specific approaches. We propose a method for the automatic localization of landmarks in complex, repetitive anatomical structures. The key idea is to combine three steps: (1) a classifier for pre-filtering anatomical landmark positions that (2) are refined through a Hough regression model, together with (3) a parts-based model of the global landmark topology to select the final landmark positions. During training landmarks are annotated in a set of example volumes. A classifier learns local landmark appearance, and Hough regressors are trained to aggregate neighborhood information to a precise landmark coordinate position. A non-parametric geometric model encodes the spatial relationships between the landmarks and derives a topology which connects mutually predictive landmarks. During the global search we classify all voxels in the query volume, and perform regression-based agglomeration of landmark probabilities to highly accurate and specific candidate points at potential landmark locations. We encode the candidates' weights together with the conformity of the connecting edges to the learnt geometric model in a Markov Random Field (MRF). By solving the corresponding discrete optimization problem, the most probable location for each model landmark is found in the query volume. We show that this approach is able to consistently localize the model landmarks despite the complex and repetitive character of the anatomical structures on three challenging data sets (hand radiographs, hand CTs, and whole body CTs), with a median localization error of 0.80 mm, 1.19 mm and 2.71 mm, respectively. PMID:23664450

  17. Laparoscopic totally extraperitoneal (TEP) hernioplasty using two trocars: anatomical landmarks and surgical technique / Hernioplastia laparoscópica totalmente extraperitoneal (TEP) utilizando dois trocárteres: reparos anatômicos e técnica cirúrgica

    Scientific Electronic Library Online (English)

    Leandro Ryuchi, IUAMOTO; Juliana Mika, KATO; Alberto, MEYER; Pierre, BLANC.

    2015-06-01

    Full Text Available RACIONAL: Dentre as correções endoscópicas das hérnias, as abordagens totalmente extraperitoneal (TEP) e transabdominal pré-peritoneal (TAPP) são amplamente aceitas como alternativas à operação aberta, fornecendo menos dor no período pós-operatório, menor tempo de permanência hospitalar e retorno p [...] recoce ao trabalho. A técnica TEP clássica requer três incisões na pele para a colocação de três trocárteres na linha média ou em triangulação. OBJETIVO: Descrever uma técnica utilizando apenas dois trocárteres para hernioplastia laparoscópica totalmente extraperitoneal (TEP). MÉTODO: Acesso extraperitoneal: são inseridos dois trocárteres sobre a linha média; um de 10 mm é inserido no subcutâneo em direção horizontal após incisão infra-umbilical transversal e, em seguida, elevado ao ângulo de 60°; outro de 5 mm é inserido ao nível do pubis com visão direta. Tempos operatórios: 1) dissecção do espaço preperitoneal: introdução da ótica laparoscópica de 0º através da incisão infra-umbilical para visualização e dissecção pré-peritoneal; pressão de insuflação inferior a 12 mmHg; 2) Dissecção de alguns reparos anatômicos: pubis, linha arqueada e vasos epigástricos inferiores; 3) reconhecimento do "triângulo da dor" e "triângulo do desastre"; 4) Inserção através do trocáter de 10 mm de tela de polipropileno de 10x15 cm para cobrir o sitio da hérnia; 5) Reposicionamento do peritônio e da borda dorsal da tela para evitar dobras ou deslocamento da tela. Não é necessária a drenagem. RESULTADOS: Esta técnica foi utilizada em nove pacientes e apresentou bom resultado sem necessidade de um cirurgião auxiliar para executá-la, apenas dois trocáteres, menos material de sutura e de curativos. Além disso, exigiu apenas duas incisões, o que proporcionou melhor resultado estético e menor dor no período pós-operatório. CONCLUSÃO: A técnica proposta utilizando dois trocárteres é uma alternativa viável, com melhora dos resultados cosméticos e financeiros. Abstract in english BACKGROUND: Among endoscopic hernioplasties, totally extraperitoneal (TEP) and transabdominal preperitoneal (TAPP) approach are widely accepted alternatives to open surgery, both providing less postoperative pain, hospital length of stay and early return to work. Classical TEP technique requires th [...] ree skin incisions for placement of three trocars in the midline or in triangulation. AIM: To describe a technique using only two trocars for laparoscopic total extraperitoneal for inguinal hernia repair. METHOD: Extraperitoneal access: place two regular trocars on the midline. The 10 mm is inserted into the subcutaneous in horizontal direction after a transverse infra-umbilical incision and then elevated at 60º angle. The 5 mm trocar is inserted at the same level of the pubis with direct vision. Preperitoneal space dissection: introduction 0º optical laparoscope through the infra-umbilical incision for visualization and preperitoneal dissection; insufflation pressure must be below 12 mmHg. Dissection of some anatomical landmarks: pubic bone, arcuate line and inferior epigastric vessels. Exposure of "triangle of pain" and "triangle of doom". Insertion through the 10 mm trocar polypropylene mesh of 10x15 cm to cover the hernia sites. Peritoneal sac and the dorsal edge of the mesh are repositioned in order to avoid bending or mesh displacement. It is also important to remember that the drainage is not necessary. RESULTS: The 2-port TEP required less financial costs than usual because it is not necessary an auxiliary surgeon to perform the technique. Trocars, suturing material and wound dressing were spared in comparison to the classical technique. Besides, there were only two incisions, which provides a better plastic result and less postoperative pain. CONCLUSION: The TEP technique using two trocars is an alternative technique which improves cosmetic and financial outcomes.

  18. A Sensor Network Data Compression Algorithm Based on Suboptimal Clustering and Virtual Landmark Routing Within Clusters

    Directory of Open Access Journals (Sweden)

    Shengqiang Li

    2010-10-01

    Full Text Available A kind of data compression algorithm for sensor networks based on suboptimal clustering and virtual landmark routing within clusters is proposed in this paper. Firstly, temporal redundancy existing in data obtained by the same node in sequential instants can be eliminated. Then sensor networks nodes will be clustered. Virtual node landmarks in clusters can be established based on cluster heads. Routing in clusters can be realized by combining a greedy algorithm and a flooding algorithm. Thirdly, a global structure tree based on cluster heads will be established. During the course of data transmissions from nodes to cluster heads and from cluster heads to sink, the spatial redundancy existing in the data will be eliminated. Only part of the raw data needs to be transmitted from nodes to sink, and all raw data can be recovered in the sink based on a compression code and part of the raw data. Consequently, node energy can be saved, largely because transmission of redundant data can be avoided. As a result the overall performance of the sensor network can obviously be improved.

  19. Biomimetic bayesian models of navigation: How are environment geometry-based and landmark-based strategies articulated in humans?

    OpenAIRE

    Diard, Julien; Panagiotaki, Panagiota; Berthoz, Alain

    2009-01-01

    We propose a computational model of human navigation, which encompasses both geometry-based and landmark-based navigation strategies. This model is based on a study of human cognitive strategies during a path memorization task in a Virtual Reality (VR) experiment. Participants were asked to memorize predefined paths in a large-scale virtual city (COSMOpoliS (c)). Our computational model qualitatively reproduces the results of this experiment. This model uses the Bayesian formalism, and focuses...

  20. Biomimetic bayesian models of navigation: How are environment geometry-based and landmark-based strategies articulated in humans?

    OpenAIRE

    Diard, Julien; Panagiotaki, Panagiota; Berthoz, Alain

    2009-01-01

    We propose a computational model of human navigation, which encompasses both geometry-based and landmark-based navigation strategies. This model is based on a study of human cognitive strategies during a path memorization task in a Virtual Reality (VR) experiment. Participants were asked to memorize prede?ned paths in a large-scale virtual city (COSMOpoliS (c)). Our computational model qualitatively reproduces the results of this experiment. This model uses the Bayesian formalism, and focuses...

  1. Percutaneous Placement of Central Venous Catheters: Comparing the Anatomical Landmark Method with the Radiologically Guided Technique for Central Venous Catheterization Through the Internal Jugular Vein in Emergent Hemodialysis Patients

    Energy Technology Data Exchange (ETDEWEB)

    Koroglu, M.; Demir, M.; Koroglu, B.K.; Sezer, M.T.; Akhan, O.; Yildiz, H.; Yavuz, L.; Baykal, B.; Oyar, O. [Suleyman Demirel Univ., Isparta (Turkey). Depts. of Radiology, Internal Medicine and Anesthesiology

    2006-02-15

    Purpose: To compare the success and immediate complication rates of the anatomical landmark method (group 1) and the radiologically (combined real-time ultrasound and fluoroscopy) guided technique (group 2) in the placement of central venous catheters in emergent hemodialysis patients. Material and Methods: The study was performed prospectively in a randomized manner. The success and immediate complication rates of radiologically guided placement of central venous access catheters through the internal jugular vein (n = 40) were compared with those of the anatomical landmark method (n 40). The success of placement, the complications, the number of passes required, and whether a single or double-wall puncture occurred were also noted and compared. Results: The groups were comparable in age and sex. The indication for catheter placement was hemodialysis access in all patients. Catheter placement was successful in all patients in group 2 and unsuccessful in 1 (2.5%) patient in group 1. All catheters functioned adequately and immediately after the placement (0% initial failure rate) in group 2, but 3 catheters (7.5% initial failure rate) were non-functional just after placement in group 1. The total number of needle passes, double venous wall puncture, and complication rate were significantly lower in group 2. Conclusion: Percutaneous central venous catheterization via the internal jugular vein can be performed by interventional radiologists with better technical success rates and lower immediate complications. In conclusion, central venous catheterization for emergent dialysis should be performed under both real-time ultrasound and fluoroscopic guidance.

  2. Percutaneous Placement of Central Venous Catheters: Comparing the Anatomical Landmark Method with the Radiologically Guided Technique for Central Venous Catheterization Through the Internal Jugular Vein in Emergent Hemodialysis Patients

    International Nuclear Information System (INIS)

    Purpose: To compare the success and immediate complication rates of the anatomical landmark method (group 1) and the radiologically (combined real-time ultrasound and fluoroscopy) guided technique (group 2) in the placement of central venous catheters in emergent hemodialysis patients. Material and Methods: The study was performed prospectively in a randomized manner. The success and immediate complication rates of radiologically guided placement of central venous access catheters through the internal jugular vein (n = 40) were compared with those of the anatomical landmark method (n 40). The success of placement, the complications, the number of passes required, and whether a single or double-wall puncture occurred were also noted and compared. Results: The groups were comparable in age and sex. The indication for catheter placement was hemodialysis access in all patients. Catheter placement was successful in all patients in group 2 and unsuccessful in 1 (2.5%) patient in group 1. All catheters functioned adequately and immediately after the placement (0% initial failure rate) in group 2, but 3 catheters (7.5% initial failure rate) were non-functional just after placement in group 1. The total number of needle passes, double venous wall puncture, and complication rate were significantly lower in group 2. Conclusion: Percutaneous central venous catheterization via the internal jugular vein can be performed by interventional radiologists with better technical success rates and lower immediate complications. In conclusion, central venous catheterization for emergent dialysis should be performed under both real-time ultrasound and fluoroscopic guidance

  3. BasemapLandmarks_CEMETERY

    Data.gov (United States)

    Vermont Center for Geographic Information — The BasemapLandmarks_CEMETERY point layer contains cemeteries in the state of Vermont. The data is based on VTrans Town Highway Maps. Some points have been moved to...

  4. Dissimilarity-based classification of anatomical tree structures

    DEFF Research Database (Denmark)

    Sørensen, Lauge Emil Borch Laurs; Lo, Pechin Chien Pau; Dirksen, Asger; Petersen, Jens; de Bruijne, Marleen

    2011-01-01

    A novel method for classification of abnormality in anatomical tree structures is presented. A tree is classified based on direct comparisons with other trees in a dissimilarity-based classification scheme. The pair-wise dissimilarity measure between two trees is based on a linear assignment betw...

  5. Dissimilarity-based classification of anatomical tree structures

    DEFF Research Database (Denmark)

    Sørensen, Lauge Emil Borch Laurs; Lo, Pechin Chien Pau; Dirksen, Asger; Petersen, Jens; de Bruijne, Marleen

    A novel method for classification of abnormality in anatomical tree structures is presented. A tree is classified based on direct comparisons with other trees in a dissimilarity-based classification scheme. The pair-wise dissimilarity measure between two trees is based on a linear assignment betw...

  6. A landmark-based method for the geometrical 3D calibration of scanning microscopes

    Energy Technology Data Exchange (ETDEWEB)

    Ritter, M.

    2007-04-27

    This thesis presents a new strategy and a spatial method for the geometric calibration of 3D measurement devices at the micro-range, based on spatial reference structures with nanometersized landmarks (nanomarkers). The new method was successfully applied for the 3D calibration of scanning probe microscopes (SPM) and confocal laser scanning microscopes (CLSM). Moreover, the spatial method was also used for the photogrammetric self-calibration of scanning electron microscopes (SEM). In order to implement the calibration strategy to all scanning microscopes used, the landmark-based principle of reference points often applied at land survey or at close-range applications has been transferred to the nano- and micro-range in the form of nanomarker. In order to function as a support to the nanomarkers, slope-shaped step pyramids have been developed and fabricated by focused ion beam (FIB) induced metal deposition. These FIB produced 3D microstructures have been sized to embrace most of the measurement volume of the scanning microscopes. Additionally, their special design allows the homogenous distribution of the nanomarkers. The nanomarkers were applied onto the support and the plateaus of the slope-step pyramids by FIB etching (milling) as landmarks with as little as several hundreds of nanometers in diameter. The nanomarkers are either of point-, or ring-shaped design. They are optimized so that they can be spatially measured by SPM and CLSM, and, imaged and photogrammetrically analyzed on the basis of SEM data. The centre of the each nanomarker serves as reference point in the measurement data or images. By applying image processing routines, the image (2D) or object (3D) coordinates of each nanomarker has been determined with subpixel accuracy. The correlative analysis of the SPM, CLSM and photogrammetric SEM measurement data after 3D calibration resulted in mean residues in the measured coordinates of as little as 13 nm. Without the coupling factors the mean residues are up to 6 times higher. By taking into account the orthogonality of the measurement coordinate axes when performing a 3D calibration, a comparative and quantitative analysis of 3D scanning microscopy has been made possible. (orig.)

  7. Dissimilarity-based classification of anatomical tree structures

    DEFF Research Database (Denmark)

    SØrensen, Lauge Emil Borch Laurs; Lo, Pechin Chien Pau

    2011-01-01

    A novel method for classification of abnormality in anatomical tree structures is presented. A tree is classified based on direct comparisons with other trees in a dissimilarity-based classification scheme. The pair-wise dissimilarity measure between two trees is based on a linear assignment between the branch feature vectors representing those trees. Hereby, localized information in the branches is collectively used in classification and variations in feature values across the tree are taken into account. An approximate anatomical correspondence between matched branches can be achieved by including anatomical features in the branch feature vectors. The proposed approach is applied to classify airway trees in computed tomography images of subjects with and without chronic obstructive pulmonary disease (COPD). Using the wall area percentage (WA%), a common measure of airway abnormality in COPD, as well as anatomical features to characterize each branch, an area under the receiver operating characteristic curveof 0.912 is achieved. This is significantly better than computing the average WA%.

  8. Image-based dose planning of intracavitary brachytherapy: registration of serial-imaging studies using deformable anatomic templates

    International Nuclear Information System (INIS)

    Purpose: To demonstrate that high-dimensional voxel-to-voxel transformations, derived from continuum mechanics models of the underlying pelvic tissues, can be used to register computed tomography (CT) serial examinations into a single anatomic frame of reference for cumulative dose calculations. Methods and Materials: Three patients with locally advanced cervix cancer were treated with CT-compatible intracavitary (ICT) applicators. Each patient underwent five volumetric CT examinations: before initiating treatment, and immediately before and after the first and second ICT insertions, respectively. Each serial examination was rigidly registered to the patient's first ICT examination by aligning the bony anatomy. Detailed nonrigid alignment for organs (or targets) of interest was subsequently achieved by deforming the CT exams as a viscous-fluid, described by the Navier-Stokes equation, until the coincidence with the corresponding targets on CT image was maximized. In cases where ICT insertion induced very large and topologically complex rearrangements of pelvic organs, e.g., extreme uterine canal reorientation following tandem insertion, a viscous-fluid-landmark transformation was used to produce an initial registration. Results: For all three patients, reasonable registrations for organs (or targets) of interest were achieved. Fluid-landmark initialization was required in 4 of the 11 registrations. Relative to the best rigid bony landmark alignment, the viscous-fluid registration resulted in average soft-tissue displacements from 2.8 to 28.1 mm, and improved organ coincidence from the range of 5.2% to 72.2% to the range of 90.6% to 100%. Compared to the viscous-fluid transformation, global registration of bony anatomy mismatched 5% or more of the contoured organ volumes by 15-25 mm. Conclusion: Pelvic soft-tissue structures undergo large deformations and displacements during the external-beam and multiple-ICT course of radiation therapy for locally advanced cervix cancer. These changes cannot be modeled by the conventional rigid landmark transformation method. In the current study, we found that the deformable anatomic template registration method, based on continuum-mechanics models of deformation, successfully described these large anatomic shape changes before and after ICT. These promising modeling results indicate that realistic registration of the cumulative dose distribution to the organs (or targets) of interest for radiation therapy of cervical cancers is achievable

  9. Look and turn: landmark-based goal navigation in honey bees.

    OpenAIRE

    Fry, S. N.; Wehner, R

    2005-01-01

    This report describes the piloting mechanisms employed by honey bees during their final approach to a goal. Conceptually applying a bottom-up approach, we systematically varied the position, number and appearance landmarks associated with a rewarded target location within a large, homogenous flight tent. The flight behavior measured under various conditions is well explained with visuo-motor control loops that link perceived landmarks with appropriate turning responses. This view is consisten...

  10. Knowledge-based recognition of man-made landmarks in a simulated control cycle using a virtual-globe system

    OpenAIRE

    Michaelsen, Eckart

    2012-01-01

    Automatic knowledge-based recognition of landmarks in aerial images for UAV navigation is an alternative to GNSS navigation. It provides absolute position estimates thus complementing INS navigation. Relying on knowledge instead of template images or training samples is advantageous because the first may be out-of-date and the latter not representative. The robustness and precision of the method can be assessed using internet-based virtual globe systems such as Google Earth as camera simulato...

  11. Anatomically based lower limb nerve model for electrical stimulation

    OpenAIRE

    Soboleva Tanya K; Röhrle Oliver; Davidson John B; Kim Juliana HK; Pullan Andrew J

    2007-01-01

    Abstract Background Functional Electrical Stimulation (FES) is a technique that aims to rehabilitate or restore functionality of skeletal muscles using external electrical stimulation. Despite the success achieved within the field of FES, there are still a number of questions that remain unanswered. One way of providing input to the answers is through the use of computational models. Methods This paper describes the development of an anatomically based computer model of the motor neurons in t...

  12. Dorsolateral Striatal Lesions Impair Navigation Based on Landmark-Goal Vectors but Facilitate Spatial Learning Based on a "Cognitive Map"

    Science.gov (United States)

    Kosaki, Yutaka; Poulter, Steven L.; Austen, Joe M.; McGregor, Anthony

    2015-01-01

    In three experiments, the nature of the interaction between multiple memory systems in rats solving a variation of a spatial task in the water maze was investigated. Throughout training rats were able to find a submerged platform at a fixed distance and direction from an intramaze landmark by learning a landmark-goal vector. Extramaze cues were…

  13. Preservation of the Optic Radiations based on comparative analysis of Diffusion Tensor Imaging Tractography and Anatomical dissection

    Directory of Open Access Journals (Sweden)

    Roland Nooij

    2015-08-01

    Full Text Available Background Visualization of the precise course of the visual pathways is relevant to prevent damage that may inflict visual field deficits during neurosurgical resections. In particular the optic radiations (OR are susceptible to such damage during neurosurgery. Cortical pathways can be mapped in vivo, by using Diffusion Tensor Imaging (DTI. Visualization of these pathways would be potentially helpful to prevent neurosurgical visual morbidity. In this study an anatomical dissection of the visual pathways was compared to DTI fiber tractography (DTI-FT data of four human brains. The feasibility of a definition of a Safety Zone is investigated. Methods Four adult brains were dissected using Klingler’s fiber dissection method, which allowed preparation of the OR. Measurements before and after dissection were used to establish distances from the cortex to the OR. DTI-scans were also obtained from these brains to determine the same distances. Results Measurements from specific landmark points on the cortex to the lateral border of the OR were performed in four brains. Analysis through DTI tractography corresponded with the dissection results. Based on the combined results of both dissection and DTI-FT, we defined a quantitative surgical Safety Zone with respect to various anatomical landmarks (in particular the ventricle system Conclusion We conclude that there is a good correlation between the visualizations of the optic pathways based on dissection and DTI. Furthermore, we conclude that defining a neurosurgical Safety Zone which could preserve the integrity of the OR during surgery, based on the combination of DTI-FT images and dissection is feasible.

  14. Reliability of lower limb alignment measures using an established landmark-based method with a customized computer software program.

    Science.gov (United States)

    Sled, Elizabeth A; Sheehy, Lisa M; Felson, David T; Costigan, Patrick A; Lam, Miu; Cooke, T Derek V

    2011-01-01

    The objective of the study was to evaluate the reliability of frontal plane lower limb alignment measures using a landmark-based method by (1) comparing inter- and intra-reader reliability between measurements of alignment obtained manually with those using a computer program, and (2) determining inter- and intra-reader reliability of computer-assisted alignment measures from full-limb radiographs. An established method for measuring alignment was used, involving selection of 10 femoral and tibial bone landmarks. (1) To compare manual and computer methods, we used digital images and matching paper copies of five alignment patterns simulating healthy and malaligned limbs drawn using AutoCAD. Seven readers were trained in each system. Paper copies were measured manually and repeat measurements were performed daily for 3 days, followed by a similar routine with the digital images using the computer. (2) To examine the reliability of computer-assisted measures from full-limb radiographs, 100 images (200 limbs) were selected as a random sample from 1,500 full-limb digital radiographs which were part of the Multicenter Osteoarthritis Study. Three trained readers used the software program to measure alignment twice from the batch of 100 images, with two or more weeks between batch handling. Manual and computer measures of alignment showed excellent agreement (intraclass correlations [ICCs] 0.977-0.999 for computer analysis; 0.820-0.995 for manual measures). The computer program applied to full-limb radiographs produced alignment measurements with high inter- and intra-reader reliability (ICCs 0.839-0.998). In conclusion, alignment measures using a bone landmark-based approach and a computer program were highly reliable between multiple readers. PMID:19882339

  15. Anatomically based lower limb nerve model for electrical stimulation

    Directory of Open Access Journals (Sweden)

    Soboleva Tanya K

    2007-12-01

    Full Text Available Abstract Background Functional Electrical Stimulation (FES is a technique that aims to rehabilitate or restore functionality of skeletal muscles using external electrical stimulation. Despite the success achieved within the field of FES, there are still a number of questions that remain unanswered. One way of providing input to the answers is through the use of computational models. Methods This paper describes the development of an anatomically based computer model of the motor neurons in the lower limb of the human leg and shows how it can be used to simulate electrical signal propagation from the beginning of the sciatic nerve to a skeletal muscle. One-dimensional cubic Hermite finite elements were used to represent the major portions of the lower limb nerves. These elements were fit to data that had been digitised using images from the Visible Man project. Nerves smaller than approximately 1 mm could not be seen in the images, and thus a tree-branching algorithm was used to connect the ends of the fitted nerve model to the respective skeletal muscle. To simulate electrical propagation, a previously published mammalian nerve model was implemented and solved on the anatomically based nerve mesh using a finite difference method. The grid points for the finite difference method were derived from the fitted finite element mesh. By adjusting the tree-branching algorithm, it is possible to represent different levels of motor-unit recruitment. Results To illustrate the process of a propagating nerve stimulus to a muscle in detail, the above method was applied to the nerve tree that connects to the human semitendinosus muscle. A conduction velocity of 89.8 m/s was obtained for a 15 ?m diameter nerve fibre. This signal was successfully propagated down the motor neurons to a selected group of motor units in the muscle. Conclusion An anatomically and physiologically based model of the posterior motor neurons in the human lower limb was developed. This model can be used to examine the effect of external stimulation on nerve and muscle activity, as may occur, for example, in the field of FES.

  16. Look and turn: landmark-based goal navigation in honey bees.

    Science.gov (United States)

    Fry, S N; Wehner, R

    2005-10-01

    This report describes the piloting mechanisms employed by honey bees during their final approach to a goal. Conceptually applying a bottom-up approach, we systematically varied the position, number and appearance landmarks associated with a rewarded target location within a large, homogenous flight tent. The flight behavior measured under various conditions is well explained with visuo-motor control loops that link perceived landmarks with appropriate turning responses. This view is consistent with the requirement of prolonged reinforcement learning for efficient goal navigation. A simple model is able to provide a comprehensive explanation for diverse flight patterns that range from convoluted searching behavior to highly idiosyncratic approaches, depending on the experimental context. Our results challenge the prevalent notion that honey bees employ image matching for visual guidance toward a goal site. Basic visuo-motor control loops may better meet the high demands for robust and fast flight control, which could serve as a powerful bio-mimetic design principle for micro-robotic aircraft. PMID:16215221

  17. Reconciling Landmarks and Level Sets

    OpenAIRE

    Maurel, Pierre; Keriven, Renaud; Faugeras, Olivier

    2006-01-01

    Shape warping is a key problem in statistical shape analysis. This paper proposes a framework for geometric shape warping based on both shape distances and landmarks. Our method is compatible with implicit representations and a matching between shape surfaces is provided at no additional cost. It is, to our knowledge, the rst time that landmarks and shape distances are reconciled in a pure geometric level set framework. The feasibility of the method is demonstrated with two- and three-dimensi...

  18. Optimization of Landmark Selection for Cortical Surface Registration

    OpenAIRE

    Joshi, Anand,; Pantazis, Dimitrios; Damasio, Hanna; Shattuck, David; Li, Quanzheng; Leahy, Richard

    2009-01-01

    Manually labeled landmark sets are often required as inputs for landmark-based image registration. Identifying an optimal subset of landmarks from a training dataset may be useful in reducing the labor intensive task of manual labeling. In this paper, we present a new problem and a method to solve it: given a set of N landmarks, find the k(< N) best landmarks such that aligning these k landmarks that produce the best overall alignment of all N landmarks. The resulting procedure allows us to s...

  19. Reproducibility of the sella turcica landmark in three dimensions using a sella turcica-specific reference system

    Energy Technology Data Exchange (ETDEWEB)

    Pittayapat, Pisha; Jacobs, Reinhilde [University Hospitals Leuven, University of Leuven, Leuven (Belgium); Odri, Guillaume A. [Service de Chirurgie Orthopedique et Traumatologique, Centre Hospitalier Regional d' Orleans, Orleans Cedex2 (France); De Faria Vasconcelos, Karla [Dept. of Oral Diagnosis, Division of Oral Radiology, Piracicaba Dental School, University of Campinas, Sao Paulo (Brazil); Willems, Guy [Dept. of Oral Health Sciences, Orthodontics, KU Leuven and Dentistry, University Hospitals Leuven, University of Leuven, Leuven (Belgium); Olszewski, Raphael [Dept. of Oral and Maxillofacial Surgery, Cliniques Universitaires Saint Luc, Universite Catholique de Louvain, Brussels (Belgium)

    2015-03-15

    This study was performed to assess the reproducibility of identifying the sella turcica landmark in a three-dimensional (3D) model by using a new sella-specific landmark reference system. Thirty-two cone-beam computed tomographic scans (3D Accuitomo 170, J. Morita, Kyoto, Japan) were retrospectively collected. The 3D data were exported into the Digital Imaging and Communications in Medicine standard and then imported into the Maxilim software (Medicim NV, Sint-Niklaas, Belgium) to create 3D surface models. Five observers identified four osseous landmarks in order to create the reference frame and then identified two sella landmarks. The x, y, and z coordinates of each landmark were exported. The observations were repeated after four weeks. Statistical analysis was performed using the multiple paired t-test with Bonferroni correction (intraobserver precision: p<0.005, interobserver precision: p<0.0011). The intraobserver mean precision of all landmarks was <1 mm. Significant differences were found when comparing the intraobserver precision of each observer (p<0.005). For the sella landmarks, the intraobserver mean precision ranged from 0.43±0.34 mm to 0.51±0.46 mm. The intraobserver reproducibility was generally good. The overall interobserver mean precision was <1 mm. Significant differences between each pair of observers for all anatomical landmarks were found (p<0.0011). The interobserver reproducibility of sella landmarks was good, with >50% precision in locating the landmark within 1 mm. A newly developed reference system offers high precision and reproducibility for sella turcica identification in a 3D model without being based on two-dimensional images derived from 3D data.

  20. Reproducibility of the sella turcica landmark in three dimensions using a sella turcica-specific reference system

    International Nuclear Information System (INIS)

    This study was performed to assess the reproducibility of identifying the sella turcica landmark in a three-dimensional (3D) model by using a new sella-specific landmark reference system. Thirty-two cone-beam computed tomographic scans (3D Accuitomo 170, J. Morita, Kyoto, Japan) were retrospectively collected. The 3D data were exported into the Digital Imaging and Communications in Medicine standard and then imported into the Maxilim software (Medicim NV, Sint-Niklaas, Belgium) to create 3D surface models. Five observers identified four osseous landmarks in order to create the reference frame and then identified two sella landmarks. The x, y, and z coordinates of each landmark were exported. The observations were repeated after four weeks. Statistical analysis was performed using the multiple paired t-test with Bonferroni correction (intraobserver precision: p<0.005, interobserver precision: p<0.0011). The intraobserver mean precision of all landmarks was <1 mm. Significant differences were found when comparing the intraobserver precision of each observer (p<0.005). For the sella landmarks, the intraobserver mean precision ranged from 0.43±0.34 mm to 0.51±0.46 mm. The intraobserver reproducibility was generally good. The overall interobserver mean precision was <1 mm. Significant differences between each pair of observers for all anatomical landmarks were found (p<0.0011). The interobserver reproducibility of sella landmarks was good, with >50% precision in locating the landmark within 1 mm. A newly developed reference system offers high precision and reproducibility for sella turcica identification in a 3D model without being based on two-dimensional images derived from 3D data.

  1. Neural Network-Based Landmark Recognition and Navigation with IAMRs. Understanding the Principles of Thought and Behavior.

    Science.gov (United States)

    Doty, Keith L.

    1999-01-01

    Research on neural networks and hippocampal function demonstrating how mammals construct mental maps and develop navigation strategies is being used to create Intelligent Autonomous Mobile Robots (IAMRs). Such robots are able to recognize landmarks and navigate without "vision." (SK)

  2. Sartorial Branch of Saphenous Nerve: Anatomical Relationship with Bony Landmarks and Great Saphenous Vein / Ramo Sartorial del Nervio Safeno Safeno: Relación Anatómica con Puntos de Referencia Óseos y de la vena Safena Magna

    Scientific Electronic Library Online (English)

    Amornrat, Tothonglor; Sithiporn, Agthong; Thanasil, Huanmanop; Vilai, Chentanez.

    2013-06-01

    Full Text Available El ramo sartorial del nervio safeno (nervio cutáneo medial de la pierna) se origina en el lado medial de la rodilla y desciende a lo largo de la vena safena magna (VSM) para inervar la cara medial de la pierna. Su anatomía es motivo de preocupación en los procedimientos quirúrgicos y en el bloqueo a [...] nestésico. Sin embargo, los datos de medición relacionados con puntos de referencia óseos palpables y la comparación entre los lados y en ambos sexos son escasas. Se realizó la disección en 95 miembros inferiores de ambos sexos. Se encontró que el nervio perforó la fascia profunda en la mayoría de los casos (92,6%). Esta punta de perforación fue siempre distal al tubérculo del músculo aductor magno a una distancia de 5-6 cm, que representaba el 15% del largo de la pierna (la distancia entre el tubérculo del aductor magno y el maléolo medial). El nervio se localizaba 7 cm medial a la tuberosidad tibial. Al nivel del tercio medio en ambas piernas, el nervio estaba a una distancia un poco mayor a 4 cm medial al margen anterior de la tibia. El nervio se dividía 7 cm proximal al maléolo medial. Por otra parte, la relación anatómica entre el nervio y la VSM fue muy variable. El nervio era constantemente anterior, posterior o profundo a la VSM en 8,4%, 15,8% y 2,1%, respectivamente. Cruce entre las dos estructuras anatómicas se observó en el 57,9% de las muestras y la distancia hasta el maléolo medial fue de 18 cm. La simetría se encuentra en la mayoría de los parámetros y diferencias de sexo significativas se observaron en algunas distancias. Estos resultados son importantes para evitar la lesión del nervio sartorial y localizar el nervio durante los procedimientos pertinentes. Abstract in english Sartorial branch of saphenous nerve (medial crural cutaneous nerve) originates at the medial side of the knee and descends along the great saphenous vein (GSV) to innervate the medial aspect of the leg. Its anatomy is of concern in surgical procedures and anesthetic block. However, the measurement d [...] ata related to palpable bony landmarks with comparison between sexes and sides are lacking. Dissection was done in 95 lower limbs from both sexes. We found that the nerve pierced the deep fascia alone in most cases (92.6%). This piercing point was always distal to the adductor tubercle with the distance of 5-6 cm which was 15% of the leg length (the distance between the adductor tubercle and medial malleolus). The nerve was 7 cm medial to the tibial tuberosity. At the mid-level of leg length, the nerve was slightly over 4 cm medial to the anterior tibial margin. The nerve terminally divided 7 cm proximal to the medial malleolus. Furthermore, the anatomical relationship between the nerve and the GSV was highly variable. The nerve was constantly anterior, posterior or deep to the GSV in 8.4%, 15.8% and 2.1%, respectively. Crossing between the two structures was observed in 57.9% of specimens and the distance to the medial malleolus was 18 cm. Symmetry was found in most parameters and significant gender differences were observed in some distances. These results are important for avoiding the sartorial nerve injury and locating the nerve during relevant procedures.

  3. 3D facial landmarks

    DEFF Research Database (Denmark)

    Fagertun, Jens; Harder, Stine; Rosengren, Anders; Moeller, Christian; Werge, Thomas; Paulsen, Rasmus R; Hansen, Thomas

    2014-01-01

    BACKGROUND: Manual annotation of landmarks is a known source of variance, which exist in all fields of medical imaging, influencing the accuracy and interpretation of the results. However, the variability of human facial landmarks is only sparsely addressed in the current literature as opposed to e.g. the research fields of orthodontics and cephalometrics. We present a full facial 3D annotation procedure and a sparse set of manually annotated landmarks, in effort to reduce operator time and mini...

  4. Control over structure-specific flexibility improves anatomical accuracy for point-based deformable registration in bladder cancer radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Wognum, S.; Chai, X.; Hulshof, M. C. C. M.; Bel, A. [Department of Radiotherapy, Academic Medical Center, Meiberdreef 9, 1105 AZ Amsterdam (Netherlands); Bondar, L.; Zolnay, A. G.; Hoogeman, M. S. [Department of Radiation Oncology, Daniel den Hoed Cancer Center, Erasmus Medical Center, Groene Hilledijk 301, 3075 EA Rotterdam (Netherlands)

    2013-02-15

    Purpose: Future developments in image guided adaptive radiotherapy (IGART) for bladder cancer require accurate deformable image registration techniques for the precise assessment of tumor and bladder motion and deformation that occur as a result of large bladder volume changes during the course of radiotherapy treatment. The aim was to employ an extended version of a point-based deformable registration algorithm that allows control over tissue-specific flexibility in combination with the authors' unique patient dataset, in order to overcome two major challenges of bladder cancer registration, i.e., the difficulty in accounting for the difference in flexibility between the bladder wall and tumor and the lack of visible anatomical landmarks for validation. Methods: The registration algorithm used in the current study is an extension of the symmetric-thin plate splines-robust point matching (S-TPS-RPM) algorithm, a symmetric feature-based registration method. The S-TPS-RPM algorithm has been previously extended to allow control over the degree of flexibility of different structures via a weight parameter. The extended weighted S-TPS-RPM algorithm was tested and validated on CT data (planning- and four to five repeat-CTs) of five urinary bladder cancer patients who received lipiodol injections before radiotherapy. The performance of the weighted S-TPS-RPM method, applied to bladder and tumor structures simultaneously, was compared with a previous version of the S-TPS-RPM algorithm applied to bladder wall structure alone and with a simultaneous nonweighted S-TPS-RPM registration of the bladder and tumor structures. Performance was assessed in terms of anatomical and geometric accuracy. The anatomical accuracy was calculated as the residual distance error (RDE) of the lipiodol markers and the geometric accuracy was determined by the surface distance, surface coverage, and inverse consistency errors. Optimal parameter values for the flexibility and bladder weight parameters were determined for the weighted S-TPS-RPM. Results: The weighted S-TPS-RPM registration algorithm with optimal parameters significantly improved the anatomical accuracy as compared to S-TPS-RPM registration of the bladder alone and reduced the range of the anatomical errors by half as compared with the simultaneous nonweighted S-TPS-RPM registration of the bladder and tumor structures. The weighted algorithm reduced the RDE range of lipiodol markers from 0.9-14 mm after rigid bone match to 0.9-4.0 mm, compared to a range of 1.1-9.1 mm with S-TPS-RPM of bladder alone and 0.9-9.4 mm for simultaneous nonweighted registration. All registration methods resulted in good geometric accuracy on the bladder; average error values were all below 1.2 mm. Conclusions: The weighted S-TPS-RPM registration algorithm with additional weight parameter allowed indirect control over structure-specific flexibility in multistructure registrations of bladder and bladder tumor, enabling anatomically coherent registrations. The availability of an anatomically validated deformable registration method opens up the horizon for improvements in IGART for bladder cancer.

  5. Control over structure-specific flexibility improves anatomical accuracy for point-based deformable registration in bladder cancer radiotherapy

    International Nuclear Information System (INIS)

    Purpose: Future developments in image guided adaptive radiotherapy (IGART) for bladder cancer require accurate deformable image registration techniques for the precise assessment of tumor and bladder motion and deformation that occur as a result of large bladder volume changes during the course of radiotherapy treatment. The aim was to employ an extended version of a point-based deformable registration algorithm that allows control over tissue-specific flexibility in combination with the authors’ unique patient dataset, in order to overcome two major challenges of bladder cancer registration, i.e., the difficulty in accounting for the difference in flexibility between the bladder wall and tumor and the lack of visible anatomical landmarks for validation. Methods: The registration algorithm used in the current study is an extension of the symmetric-thin plate splines-robust point matching (S-TPS-RPM) algorithm, a symmetric feature-based registration method. The S-TPS-RPM algorithm has been previously extended to allow control over the degree of flexibility of different structures via a weight parameter. The extended weighted S-TPS-RPM algorithm was tested and validated on CT data (planning- and four to five repeat-CTs) of five urinary bladder cancer patients who received lipiodol injections before radiotherapy. The performance of the weighted S-TPS-RPM method, applied to bladder and tumor structures simultaneously, was compared with a previous version of the S-TPS-RPM algorithm applied to bladder wall structure alone and with a simultaneous nonweighted S-TPS-RPM registration of the bladder and tumor structures. Performance was assessed in terms of anatomical and geometric accuracy. The anatomical accuracy was calculated as the residual distance error (RDE) of the lipiodol markers and the geometric accuracy was determined by the surface distance, surface coverage, and inverse consistency errors. Optimal parameter values for the flexibility and bladder weight parameters were determined for the weighted S-TPS-RPM. Results: The weighted S-TPS-RPM registration algorithm with optimal parameters significantly improved the anatomical accuracy as compared to S-TPS-RPM registration of the bladder alone and reduced the range of the anatomical errors by half as compared with the simultaneous nonweighted S-TPS-RPM registration of the bladder and tumor structures. The weighted algorithm reduced the RDE range of lipiodol markers from 0.9–14 mm after rigid bone match to 0.9–4.0 mm, compared to a range of 1.1–9.1 mm with S-TPS-RPM of bladder alone and 0.9–9.4 mm for simultaneous nonweighted registration. All registration methods resulted in good geometric accuracy on the bladder; average error values were all below 1.2 mm. Conclusions: The weighted S-TPS-RPM registration algorithm with additional weight parameter allowed indirect control over structure-specific flexibility in multistructure registrations of bladder and bladder tumor, enabling anatomically coherent registrations. The availability of an anatomically validated deformable registration method opens up the horizon for improvements in IGART for bladder cancer.

  6. Piriformis Fossa – An Anatomical and Orthopedics Consideration

    OpenAIRE

    O. P. Lakhwani; Mittal, P.S.; Naik, D.C.

    2014-01-01

    Introduction: Piriformis fossa is an important anatomical landmark having significant clinical value in orthopedic surgery; but its location and anatomical relationship with surrounding structures are not clearly defined. Hence it is necessary to clearly describe it in respect to anatomical and orthopedic aspect.

  7. Landmarks in Hybrid Planning

    Directory of Open Access Journals (Sweden)

    Mohamed Elkawkagy

    2013-11-01

    Full Text Available Although planning techniques achieved a significant progress during recent years, solving many planning problem still difficult even for modern planners. In this paper, we will adopt landmark concept to hybrid planning setting - a method that combines reasoning about procedural knowledge and causalities. Land-marks are a well-known concept in the realm of classical planning. Recently, they have been adapted to hierarchical approaches. Such landmarks can be extracted in a pre-processing step from a declarative hierarchical planning domain and problem description. It was shown how this technique allows for a considerable reduction of the search space by eliminating futile plan development options before the actual planning. Therefore, we will present a new approach to in¬tegrate landmark pre-processing technique in the context of hierarchical planning with landmark technique in the classical planning. This integration allows to incorporate the ability of using extracted landmark tasks from hierarchical domain knowledge in the form of HTN and using landmark literals from classical planning. To this end, we will construct a transformation technique to transform the hybrid planning domain into a classical domain model. The method¬ologies in this paper have been implemented successfully, and we will present some experimental results that give evidence for the consid-erable performance increase gained through planning system.

  8. Landmarks in Linoleum

    Science.gov (United States)

    Skophammer, Karen

    2010-01-01

    This printmaking unit will get students excited about geography and history. In this article, the author describes how her eighth-grade students created a report and a linoleum print of a famous "landmark."

  9. BasemapLandmarks_GEONAME

    Data.gov (United States)

    Vermont Center for Geographic Information — BasemapLandmarks_GEONAME is derived from the US Geological Survey's National Geographic Names Database (GNIS). The data were obtained by VCGI for distribution.

  10. FlyBase: anatomical data, images and queries

    OpenAIRE

    Grumbling, Gary; Strelets, Victor

    2005-01-01

    FlyBase () is a database of genetic and genomic data on the model organism Drosophila melanogaster and the entire insect family Drosophilidae. The FlyBase Consortium curates, annotates, integrates and maintains a wide variety of data within this domain. Access to the data is provided through graphical and textual user interfaces tailored to particular types of data. FlyBase data types include maps at the cytological, genetic and sequence levels, genes and alleles including their products, fun...

  11. Automatic Insall-Salvati ratio measurement on lateral knee x-ray images using model-guided landmark localization

    International Nuclear Information System (INIS)

    The Insall-Salvati ratio (ISR) is important for detecting two common clinical signs of knee disease: patella alta and patella baja. Furthermore, large inter-operator differences in ISR measurement make an objective measurement system necessary for better clinical evaluation. In this paper, we define three specific bony landmarks for determining the ISR and then propose an x-ray image analysis system to localize these landmarks and measure the ISR. Due to inherent artifacts in x-ray images, such as unevenly distributed intensities, which make landmark localization difficult, we hence propose a registration-assisted active-shape model (RAASM) to localize these landmarks. We first construct a statistical model from a set of training images based on x-ray image intensity and patella shape. Since a knee x-ray image contains specific anatomical structures, we then design an algorithm, based on edge tracing, for patella feature extraction in order to automatically align the model to the patella image. We can estimate the landmark locations as well as the ISR after registration-assisted model fitting. Our proposed method successfully overcomes drawbacks caused by x-ray image artifacts. Experimental results show great agreement between the ISRs measured by the proposed method and by orthopedic clinicians.

  12. Automatic Insall-Salvati ratio measurement on lateral knee x-ray images using model-guided landmark localization

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Hsin-Chen; Wu, Chia-Hsing; Sun, Yung-Nien [Department of Computer Science and Information Engineering, National Cheng Kung University, 1 University Road, Tainan 701, Taiwan (China); Lin, Chii-Jeng [Department of Orthopedics, College of Medicine, National Cheng Kung University, 138 Sheng Li Road, Tainan 704, Taiwan (China); Wang, Chien-Kuo, E-mail: ynsun@mail.ncku.edu.t, E-mail: wale1212@gmail.co, E-mail: btmage@gmail.co, E-mail: mark@mail.ncku.edu.t, E-mail: n044206@mail.hosp.ncku.edu.t [Department of Radiology, National Cheng Kung University Hospital, 138 Sheng Li Road, Tainan 704, Taiwan (China)

    2010-11-21

    The Insall-Salvati ratio (ISR) is important for detecting two common clinical signs of knee disease: patella alta and patella baja. Furthermore, large inter-operator differences in ISR measurement make an objective measurement system necessary for better clinical evaluation. In this paper, we define three specific bony landmarks for determining the ISR and then propose an x-ray image analysis system to localize these landmarks and measure the ISR. Due to inherent artifacts in x-ray images, such as unevenly distributed intensities, which make landmark localization difficult, we hence propose a registration-assisted active-shape model (RAASM) to localize these landmarks. We first construct a statistical model from a set of training images based on x-ray image intensity and patella shape. Since a knee x-ray image contains specific anatomical structures, we then design an algorithm, based on edge tracing, for patella feature extraction in order to automatically align the model to the patella image. We can estimate the landmark locations as well as the ISR after registration-assisted model fitting. Our proposed method successfully overcomes drawbacks caused by x-ray image artifacts. Experimental results show great agreement between the ISRs measured by the proposed method and by orthopedic clinicians.

  13. Validation of Setaria (L. P. Beauv Species based on Palyonological and Anatomical Techniques.

    Directory of Open Access Journals (Sweden)

    Abdul nazir

    2014-05-01

    Full Text Available In present study external morphology, leaf epidermal anatomy and pollen structureof three species of genus Setaria(Poaceaeviz., S. glauca, S. verticillata and S. viridiswere studied. The major emphasis was on the importance of palyno-anatomical characters used as an aid in plant systematics. Light microscopy (LM and scanning electron microscopy (SEMwere used to study leaf epidermal anatomy and pollen structure.Palyno-anatomical analysis of genus Setaria shows variations within the species. It is stated that the study based on classical and modern approaches is very useful for systematic delimitation of problematic taxa like Setaria.

  14. Prostatome: A combined anatomical and disease based MRI atlas of the prostate

    International Nuclear Information System (INIS)

    Purpose: In this work, the authors introduce a novel framework, the anatomically constrained registration (AnCoR) scheme and apply it to create a fused anatomic-disease atlas of the prostate which the authors refer to as the prostatome. The prostatome combines a MRI based anatomic and a histology based disease atlas. Statistical imaging atlases allow for the integration of information across multiple scales and imaging modalities into a single canonical representation, in turn enabling a fused anatomical-disease representation which may facilitate the characterization of disease appearance relative to anatomic structures. While statistical atlases have been extensively developed and studied for the brain, approaches that have attempted to combine pathology and imaging data for study of prostate pathology are not extant. This works seeks to address this gap. Methods: The AnCoR framework optimizes a scoring function composed of two surface (prostate and central gland) misalignment measures and one intensity-based similarity term. This ensures the correct mapping of anatomic regions into the atlas, even when regional MRI intensities are inconsistent or highly variable between subjects. The framework allows for creation of an anatomic imaging and a disease atlas, while enabling their fusion into the anatomic imaging-disease atlas. The atlas presented here was constructed using 83 subjects with biopsy confirmed cancer who had pre-operative MRI (collected at two institutions) followed by radical prostatectomy. The imaging atlas results from mapping thein vivo MRI into the canonical space, while the anatomic regions serve as domain constraints. Elastic co-registration MRI and corresponding ex vivo histology provides “ground truth” mapping of cancer extent on in vivo imaging for 23 subjects. Results: AnCoR was evaluated relative to alternative construction strategies that use either MRI intensities or the prostate surface alone for registration. The AnCoR framework yielded a central gland Dice similarity coefficient (DSC) of 90%, and prostate DSC of 88%, while the misalignment of the urethra and verumontanum was found to be 3.45 mm, and 4.73 mm, respectively, which were measured to be significantly smaller compared to the alternative strategies. As might have been anticipated from our limited cohort of biopsy confirmed cancers, the disease atlas showed that most of the tumor extent was limited to the peripheral zone. Moreover, central gland tumors were typically larger in size, possibly because they are only discernible at a much later stage. Conclusions: The authors presented the AnCoR framework to explicitly model anatomic constraints for the construction of a fused anatomic imaging-disease atlas. The framework was applied to constructing a preliminary version of an anatomic-disease atlas of the prostate, the prostatome. The prostatome could facilitate the quantitative characterization of gland morphology and imaging features of prostate cancer. These techniques, may be applied on a large sample size data set to create a fully developed prostatome that could serve as a spatial prior for targeted biopsies by urologists. Additionally, the AnCoR framework could allow for incorporation of complementary imaging and molecular data, thereby enabling their careful correlation for population based radio-omics studies

  15. Texture-based approaches for identifying neuro-anatomical structures and electrode tracks.

    Science.gov (United States)

    Xiang, Yongqing; Büttner-Ennever, Jean; Cohen, Bernard; Raphan, Theodore

    2004-06-01

    An automated approach to identifying electrode tracks and neuro-anatomical structures (nuclei) was developed using texture attributes of their neuro-anatomical stains. The properties that make up the texture features of the nuclei include size, shape and distribution of elemental structures. The electrode tracks are characterized by elongated darkened formations due to gliosis. Based on a Gabor wavelet transform, a texture feature vector was constructed, consisting of localized texture energies along different orientations at different scales. Stained images of brainstem sections in the vestibular nuclei were segmented using partitional clustering in feature space. A metric that computes the location of the tracks relative to the nuclei centers was then implemented. This methodology should be useful for quantifying and automating the procedure by which tracks are localized in anatomical structures. PMID:15135573

  16. Prostatome: A combined anatomical and disease based MRI atlas of the prostate

    Energy Technology Data Exchange (ETDEWEB)

    Rusu, Mirabela; Madabhushi, Anant, E-mail: anant.madabhushi@case.edu [Case Western Reserve University, Cleveland, Ohio 44106 (United States); Bloch, B. Nicolas; Jaffe, Carl C. [Boston University School of Medicine, Boston, Massachusetts 02118 (United States); Genega, Elizabeth M. [Beth Israel Deaconess Medical Center, Boston, Massachusetts 02215 (United States); Lenkinski, Robert E.; Rofsky, Neil M. [UT Southwestern Medical Center, Dallas, Texas 75235 (United States); Feleppa, Ernest [Riverside Research Institute, New York, New York 10038 (United States)

    2014-07-15

    Purpose: In this work, the authors introduce a novel framework, the anatomically constrained registration (AnCoR) scheme and apply it to create a fused anatomic-disease atlas of the prostate which the authors refer to as the prostatome. The prostatome combines a MRI based anatomic and a histology based disease atlas. Statistical imaging atlases allow for the integration of information across multiple scales and imaging modalities into a single canonical representation, in turn enabling a fused anatomical-disease representation which may facilitate the characterization of disease appearance relative to anatomic structures. While statistical atlases have been extensively developed and studied for the brain, approaches that have attempted to combine pathology and imaging data for study of prostate pathology are not extant. This works seeks to address this gap. Methods: The AnCoR framework optimizes a scoring function composed of two surface (prostate and central gland) misalignment measures and one intensity-based similarity term. This ensures the correct mapping of anatomic regions into the atlas, even when regional MRI intensities are inconsistent or highly variable between subjects. The framework allows for creation of an anatomic imaging and a disease atlas, while enabling their fusion into the anatomic imaging-disease atlas. The atlas presented here was constructed using 83 subjects with biopsy confirmed cancer who had pre-operative MRI (collected at two institutions) followed by radical prostatectomy. The imaging atlas results from mapping thein vivo MRI into the canonical space, while the anatomic regions serve as domain constraints. Elastic co-registration MRI and corresponding ex vivo histology provides “ground truth” mapping of cancer extent on in vivo imaging for 23 subjects. Results: AnCoR was evaluated relative to alternative construction strategies that use either MRI intensities or the prostate surface alone for registration. The AnCoR framework yielded a central gland Dice similarity coefficient (DSC) of 90%, and prostate DSC of 88%, while the misalignment of the urethra and verumontanum was found to be 3.45 mm, and 4.73 mm, respectively, which were measured to be significantly smaller compared to the alternative strategies. As might have been anticipated from our limited cohort of biopsy confirmed cancers, the disease atlas showed that most of the tumor extent was limited to the peripheral zone. Moreover, central gland tumors were typically larger in size, possibly because they are only discernible at a much later stage. Conclusions: The authors presented the AnCoR framework to explicitly model anatomic constraints for the construction of a fused anatomic imaging-disease atlas. The framework was applied to constructing a preliminary version of an anatomic-disease atlas of the prostate, the prostatome. The prostatome could facilitate the quantitative characterization of gland morphology and imaging features of prostate cancer. These techniques, may be applied on a large sample size data set to create a fully developed prostatome that could serve as a spatial prior for targeted biopsies by urologists. Additionally, the AnCoR framework could allow for incorporation of complementary imaging and molecular data, thereby enabling their careful correlation for population based radio-omics studies.

  17. First Steps toward Location of Landmarks on X-Ray Images

    OpenAIRE

    Desvignes, Michel; Romaniuk, Barbara; Clouard, Régis; Demoment, Ronan; Revenu, Marinette; Deshayes, Marie-Josèphe

    2000-01-01

    We address the problem of locating some anatomical bone structures on lateral cranial X-ray images. These structures are landmarks used in orthodontic therapy. The main problem in this pattern recognition application is that the landmarks are difficult to distinguish on images even for the human expert, because of lateral projection of the X-ray process. We propose a 3 steps approach: the first step provides a statistical estimation of the landmarks, using an adaptive coordinates space; the s...

  18. Geodesic atlas-based labeling of anatomical trees

    DEFF Research Database (Denmark)

    Feragen, Aasa; Petersen, Jens; Owen, Megan; Lo, Pechin; Thomsen, Laura Hohwu; Wille, Mathilde Marie Winkler; Dirksen, Asger; de Bruijne, Marleen

    2015-01-01

    We present a fast and robust atlas-based algorithm for labeling airway trees, using geodesic distances in a geometric tree-space. Possible branch label configurations for an unlabeled airway tree are evaluated using distances to a training set of labeled airway trees. In tree-space, airway tree...

  19. Non-rigid landmark-based large-scale image registration in 3-D reconstruction of mouse and rat kidney nephrons

    DEFF Research Database (Denmark)

    Zhang, Yan-Ling; Chang, Shi-Jie

    2015-01-01

    BACKGROUND: Serial histological sections are suffering from mechanical distortions that disturb the reconstruction of 3-D objects. We have corrected such artifacts with a non-rigid landmark-based method that respects the original geometry in the tissue block. The method is exemplified on a large scale in the registration of semi-thin serial sections of the mouse and rat kidneys, and has been tested on FFPE-sections. AIM: In this study of mouse and rat kidneys, we have measured and characterized the deformations introduced in the preparation of 2.5-?m-thick Epon sections and then eliminated them by a landmark-based non-rigid transformation (NRT). METHODS: We obtained 2.5-?m-thick serial Epon sections from three mouse kidneys and three rat kidneys for 3-D reconstruction of the nephron tubules. First, the images from 3000 serial mouse and 13,000 serial rat sections underwent a classic rigid registration (CRR), and the distortions were measured and indexed. The section images underwent a further NRT in order tocompensate for the deformations. The NRT used is a classic interactive landmark-based approach. The quality of the NRT was verified by comparing the geometry of the transformed images with corresponding block images. RESULTS: After CRR, the 2.5-?m-thick sections had a linear deformation of up to 2%, the tubular lengths were overestimated with up to 1.5×, and it was most difficult to trace the tubules from section to section. After the additional NRT, the geometry of the images reflected the original geometry in the block, the tubular lengths were no longer overestimated, and the NRT highly facilitated the tracing of the tubular system. CONCLUSIONS: NRT has facilitated the tracing of the tubular system in kidneys, a tracing, which would otherwise have been most difficult to perform. NRT has yielded substantial new knowledge to segmental and spatial nephron organization in the mouse and rat kidneys.

  20. 3D ultrasound-CT registration of the liver using combined landmark-intensity information

    International Nuclear Information System (INIS)

    An important issue in computer-assisted surgery of the liver is a fast and reliable transfer of preoperative resection plans to the intraoperative situation. One problem is to match the planning data, derived from preoperative CT or MR images, with 3D ultrasound images of the liver, acquired during surgery. As the liver deforms significantly in the intraoperative situation non-rigid registration is necessary. This is a particularly challenging task because pre- and intraoperative image data stem from different modalities and ultrasound images are generally very noisy. One way to overcome these problems is to incorporate prior knowledge into the registration process. We propose a method of combining anatomical landmark information with a fast non-parametric intensity registration approach. Mathematically, this leads to a constrained optimization problem. As distance measure we use the normalized gradient field which allows for multimodal image registration. A qualitative and quantitative validation on clinical liver data sets of three different patients has been performed. We used the distance of dense corresponding points on vessel center lines for quantitative validation. The combined landmark and intensity approach improves the mean and percentage of point distances above 3 mm compared to rigid and thin-plate spline registration based only on landmarks. The proposed algorithm offers the possibility to incorporate additional a priori knowledge - in terms of few landmarks - provided by a human expert into a non-rigid registration process. (orig.)

  1. The reliability of tablet computers in depicting maxillofacial radiographic landmarks

    International Nuclear Information System (INIS)

    This study was performed to evaluate the reliability of the identification of anatomical landmarks in panoramic and lateral cephalometric radiographs on a standard medical grade picture archiving communication system (PACS) monitor and a tablet computer (iPad 5). A total of 1000 radiographs, including 500 panoramic and 500 lateral cephalometric radiographs, were retrieved from the de-identified dataset of the archive of the Section of Oral and Maxillofacial Radiology of the University Of Connecticut School Of Dental Medicine. Major radiographic anatomical landmarks were independently reviewed by two examiners on both displays. The examiners initially reviewed ten panoramic and ten lateral cephalometric radiographs using each imaging system, in order to verify interoperator agreement in landmark identification. The images were scored on a four-point scale reflecting the diagnostic image quality and exposure level of the images. Statistical analysis showed no significant difference between the two displays regarding the visibility and clarity of the landmarks in either the panoramic or cephalometric radiographs. Tablet computers can reliably show anatomical landmarks in panoramic and lateral cephalometric radiographs

  2. The reliability of tablet computers in depicting maxillofacial radiographic landmarks

    Energy Technology Data Exchange (ETDEWEB)

    Tadinada, Aditya; Mahdian, Mina; Sheth, Sonam; Chandhoke, Taranpreet K.; Gopalakrishna, Aadarsh; Potluri, Anitha; Yadav, Sumit [University of Connecticut School of Dental Medicine, Farmington (United States)

    2015-09-15

    This study was performed to evaluate the reliability of the identification of anatomical landmarks in panoramic and lateral cephalometric radiographs on a standard medical grade picture archiving communication system (PACS) monitor and a tablet computer (iPad 5). A total of 1000 radiographs, including 500 panoramic and 500 lateral cephalometric radiographs, were retrieved from the de-identified dataset of the archive of the Section of Oral and Maxillofacial Radiology of the University Of Connecticut School Of Dental Medicine. Major radiographic anatomical landmarks were independently reviewed by two examiners on both displays. The examiners initially reviewed ten panoramic and ten lateral cephalometric radiographs using each imaging system, in order to verify interoperator agreement in landmark identification. The images were scored on a four-point scale reflecting the diagnostic image quality and exposure level of the images. Statistical analysis showed no significant difference between the two displays regarding the visibility and clarity of the landmarks in either the panoramic or cephalometric radiographs. Tablet computers can reliably show anatomical landmarks in panoramic and lateral cephalometric radiographs.

  3. Non-rigid landmark-based large-scale image registration in 3-D reconstruction of mouse and rat kidney nephrons

    DEFF Research Database (Denmark)

    Zhang, Yan-Ling; Chang, Shi-Jie; Zhai, Xiao-Yue; Thomsen, Jesper Skovhus; Christensen, Erik I; Andreasen, Arne

    2015-01-01

    BACKGROUND: Serial histological sections are suffering from mechanical distortions that disturb the reconstruction of 3-D objects. We have corrected such artifacts with a non-rigid landmark-based method that respects the original geometry in the tissue block. The method is exemplified on a large scale in the registration of semi-thin serial sections of the mouse and rat kidneys, and has been tested on FFPE-sections. AIM: In this study of mouse and rat kidneys, we have measured and characterized ...

  4. Automatic Landmark Identification in Mars Orbital Imagery

    Science.gov (United States)

    Wagstaff, K. L.; Panetta, J.; Greeley, R.; Schorghofer, N.; Bunte, M.; Hoffer, M. P.; Ansar, A.

    2008-12-01

    We have developed new methods for automatically identifying landmarks such as craters, gullies, dark slope streaks, and dust devil tracks in remote sensing imagery. These methods are based on statistical measures of local terrain salience. The salience of a region is defined as the degree to which it differs from its surrounding context. We use pixel intensity histograms to represent each candidate region, and we compute salience in one of two ways. The first method calculates the Kullback-Leibler divergence between the region's histogram and a larger enclosing region. The second method calculates the entropy of the region's histogram independently. The KL-divergence approach is useful for detecting unusual landmarks, while the entropy approach detects high-contrast features such as ridges and crater edges. We have automatically identified landmarks in several Mars surface images collected from orbit (MOC and THEMIS data) and evaluated them against manual annotations of dark slope streaks and dust devil tracks. We have also trained a landmark machine classifier that can assign new landmarks to one of several categories. In an evaluation on dark slope streaks, dust devil tracks, and craters, the classifier achieved an accuracy of 93%. Further, because detections are made based on a generic notion of salience, they are not restricted to known landmark types. It is possible to identify landmarks that do not fit into any existing category as novel features, enabling scientific advances that otherwise rely on serendipity to bring them to light. Automated landmark identification can be useful both onboard a remote spacecraft and in ground-based processing on the Earth. In an onboard setting, salient landmarks can be detected and catalogued as they are observed, providing a highly compressed summary of the region under study (e.g., "five craters, two gullies, and 37 sand dunes" along with their locations). On the ground, gigabyte archives of past images can be analyzed and annotated with meta-data indicating the existence and location of different landmark types. These annotations can enable a content-based search facility that will permit the easy retrieval of images that contain a specific feature of interest.

  5. Relative warps meet cladistics: A contribution to the phylogenetic relationships ofbaleen whales based on landmark analyses of mysticete crania

    Directory of Open Access Journals (Sweden)

    Hampe O Baszio S

    2010-06-01

    Full Text Available During the last few years research on fossil baleen whales experienced a renaissance. Several important fossils weredescribed, and new and extended cladistic analyses were performed, partly including molecular data from living species.Despite the progress in our knowledge of their phylogeny, many questions have still not been resolved. A different attemptto illustrate mysticete relationships is presented here using landmark analyses. For the present analysis, 38 dorsalviews of mysticete skulls and skull reconstructions were scanned and thirteen landmarks were defined. The method usedis the relative warp analysis. This method allows a clustering of elements according to their similarity in shape. The calculatedrelative warps explain main shape variations in the sample. As in parsimony analyses the toothed mysticetes areclearly distinguishable. Representatives of the Aetocetoidea are grouped very closely together and therefore their classificationin this family is strongly supported. The performed analysis shows that the crania of the Balaenidae have developedsimilarities to the cranium of Janjucetus hunderi. The restriction of the Cetotheriidae to a small group of taxa isconfirmed here and includes in this analysis Cetotherium, Mixocetus, Piscobalaena, and Titanocetus with a close relationshipto the living gray whale. The stem-balaenopterids do not show any clear signals in the present analysis. There isno support for a subdivision into further families. The structure of the dorsal cranium of Protororqualus andPraemegaptera is very similar to that of Balaenoptera

  6. Facial Landmarks Localization Estimation by Cascaded Boosted Regression

    OpenAIRE

    Chevallier, Louis; Vigouroux, Jean-Ronan; Goguey, Alix; Ozerov, Alexey

    2013-01-01

    Accurate detection of facial landmarks is very important for many applications like face recognition or analysis. In this paper we describe an efficient detector of facial landmarks based on a cascade of boosted regressors of arbitrary number of levels. We define as many regressors as landmarks and we train them separately. We describe how the training is conducted for the series of regressors by supplying training samples centered on the predictions of the previous levels. We employ gradient...

  7. Planning of landmark recognition of autonomous mobile robot (PLAS)

    Energy Technology Data Exchange (ETDEWEB)

    Abe, Y.; Sakamoto, S. [Shinryo Corp., Tokyo (Japan); Fukuda, T.; Arai, F.; Ito, S. [Nagoya University, Nagoya (Japan)

    2000-05-25

    We have developed a novel nevigation system for autonomous mobile robots called the Planning of Landmark Sensing (PLAS) system which takes into account realistic environmental conditions. When a robot moves, the robot usually resets the accumulated position errors in its navigation model by sensing a landmark. In our previous work, these errors were estimated based on robot models, and a Kalman Filter was used to reset the errors after the landmark was sensed. In this method, only the spatial relation of the robot and the landmark was considered to influence the observation noise of the Kalman Filter. But, environmental conditions, like the lighting of the room, are likely to cause the misrecognition of a landmark. Therefore, we have incorporated environmental conditions into the model of the observation noise. This helps our system to recognize the possibility of a misrecognition in bad sensing environments. As a result, our navigation system allows robots to navigate precisely, even in environments not optimal for landmark sensing. (author)

  8. Ordered Landmarks in Planning

    CERN Document Server

    Hoffmann, J; Sebastia, L; 10.1613/jair.1492

    2011-01-01

    Many known planning tasks have inherent constraints concerning the best order in which to achieve the goals. A number of research efforts have been made to detect such constraints and to use them for guiding search, in the hope of speeding up the planning process. We go beyond the previous approaches by considering ordering constraints not only over the (top-level) goals, but also over the sub-goals that will necessarily arise during planning. Landmarks are facts that must be true at some point in every valid solution plan. We extend Koehler and Hoffmann's definition of reasonable orders between top level goals to the more general case of landmarks. We show how landmarks can be found, how their reasonable orders can be approximated, and how this information can be used to decompose a given planning task into several smaller sub-tasks. Our methodology is completely domain- and planner-independent. The implementation demonstrates that the approach can yield significant runtime performance improvements when used...

  9. Gastric bare area involvement by gastric carcinoma: CT features and anatomic-pathological bases

    International Nuclear Information System (INIS)

    Objective: To investigate the CT features of gastric bare area (GBA) involvement by gastric carcinoma and their anatomic-pathological bases. Methods: CT images of 110 consecutive proximal gastric carcinoma(PGC) cases were retrospectively studied. Of them, 46 cases of GBA involvement were confirmed by surgery and pathology. CT features of GBA involvement by gastric carcinoma and their anatomic-pathological bases were analyzed. Results: The lesion appeared as mass in bare area in 38 cases and as metastatic lymphadenopathy in 8 cases. CT features of GBA involvement included: (1) Gastric bare area was widened. The thin fat strip between gastric wall and diaphragm obscured, or even disappeared (36 cases). (2) Soft tissue density mass with heterogeneous enhancement (38 cases) or round lymph nodes (8 cases) was seen in GBA. (3) Left diaphragmatic crus or gastrophrenic ligament irregularly thickening was presented and could not be separated from mass tissue (25 cases). (4) Other metastatic lymph nodes located in subphrenic extra-peritoneal space might also be revealed (3 cases). Conclusion: GBA involvement by gastric carcinomas shows some characteristic CT signs. GBA involvement by gastric carcinoma attributes to anatomic location and lymphatic drainage of PGC, also may be relevant to poor prognosis. (authors)

  10. Cryptic Species or Inadequate Taxonomy? Implementation of 2D Geometric Morphometrics Based on Integumental Organs as Landmarks for Delimitation and Description of Copepod Taxa.

    Science.gov (United States)

    Karanovic, Tomislav; Djurakic, Marko; Eberhard, Stefan M

    2016-03-01

    Discovery of cryptic species using molecular tools has become common in many animal groups but it is rarely accompanied by morphological revision, creating ongoing problems in taxonomy and conservation. In copepods, cryptic species have been discovered in most groups where fast-evolving molecular markers were employed. In this study at Yeelirrie in Western Australia we investigate a subterranean species complex belonging to the harpacticoid genus Schizopera Sars, 1905, using both the barcoding mitochondrial COI gene and landmark-based two-dimensional geometric morphometrics. Integumental organs (sensilla and pores) are used as landmarks for the first time in any crustacean group. Complete congruence between DNA-based species delimitation and relative position of integumental organs in two independent morphological structures suggests the existence of three distinct evolutionary units. We describe two of them as new species, employing a condensed taxonomic format appropriate for cryptic species. We argue that many supposedly cryptic species might not be cryptic if researchers focus on analyzing morphological structures with multivariate tools that explicitly take into account geometry of the phenotype. A perceived supremacy of molecular methods in detecting cryptic species is in our view a consequence of disparity of investment and unexploited recent advancements in morphometrics among taxonomists. Our study shows that morphometric data alone could be used to find diagnostic morphological traits and gives hope to anyone studying small animals with a hard integument or shell, especially opening the door to assessing fossil diversity and rich museum collections. We expect that simultaneous use of molecular tools with geometry-oriented morphometrics may yield faster formal description of species. Decrypted species in this study are a good example for urgency of formal descriptions, as they display short-range endemism in small groundwater calcrete aquifers in a paleochannel, where their conservation may be threatened by proposed mining. PMID:26608965

  11. Enhancing Planning Heuristic with Landmarks

    OpenAIRE

    Jingjing Zhao; Dayou Liu; Yongming Yang

    2011-01-01

    Recently, landmarks count heuristic can increase the number of problem instances solved and improve the quality of the solutions in satisfying non-optimal planning.  In order to make the heuristic optimal, we give the solution to solve the overestimate of landmarks count heuristic. We extend landmarks count heuristic without action cost assignments, and prove that the extension of heuristic is admissible. Our empirical evaluation shows that the extension of heuristic is admissible and ca...

  12. Early fetal anatomical sonography.

    LENUS (Irish Health Repository)

    Donnelly, Jennifer C

    2012-10-01

    Over the past decade, prenatal screening and diagnosis has moved from the second into the first trimester, with aneuploidy screening becoming both feasible and effective. With vast improvements in ultrasound technology, sonologists can now image the fetus in greater detail at all gestational ages. In the hands of experienced sonographers, anatomic surveys between 11 and 14 weeks can be carried out with good visualisation rates of many structures. It is important to be familiar with the normal development of the embryo and fetus, and to be aware of the major anatomical landmarks whose absence or presence may be deemed normal or abnormal depending on the gestational age. Some structural abnormalities will nearly always be detected, some will never be and some are potentially detectable depending on a number of factors.

  13. Construction and Biomechanical Properties of PolyAxial Self-Locking Anatomical Plate Based on the Geometry of Distal Tibia

    OpenAIRE

    Weiguo Liang; Weixiong Ye; Dongping Ye; Ziqiang Zhou; Zhiguang Chen; Aiguo Li; Zong-Han Xie; Lihai Zhang; Jiake Xu

    2014-01-01

    In order to provide scientific and empirical evidence for the clinical application of the polyaxial self-locking anatomical plate, 80 human tibias from healthy adults were scanned by spiral CT and their three-dimensional images were reconstructed using the surface shaded display (SSD) method. Firstly, based on the geometric data of distal tibia, a polyaxial self-locking anatomical plate for distal tibia was designed and constructed. Biomechanical tests were then performed by applying axial lo...

  14. Application of a rules-based natural language parser to critical value reporting in anatomic pathology.

    Science.gov (United States)

    Owens, Scott R; Balis, Ulysses G J; Lucas, David R; Myers, Jeffrey L

    2012-03-01

    Critical values in anatomic pathology are rare occurrences and difficult to define with precision. Nevertheless, accrediting institutions require effective and timely communication of all critical values generated by clinical and anatomic laboratories. Provisional gating criteria for potentially critical anatomic diagnoses have been proposed, with some success in their implementation reported in the literature. Ensuring effective communication is challenging, however, making the case for programmatic implementation of a turnkey-style integrated information technology solution. To address this need, we developed a generically deployable laboratory information system-based tool, using a tiered natural language processing predicate calculus inference engine to identify qualifying cases that meet criteria for critical diagnoses but lack an indication in the electronic medical record for an appropriate clinical discussion with the ordering physician of record. Using this tool, we identified an initial cohort of 13,790 cases over a 49-month period, which were further explored by reviewing the available electronic medical record for each patient. Of these cases, 35 (0.3%) were judged to require intervention in the form of direct communication between the attending pathologist and the clinical physician of record. In 8 of the 35 cases, this intervention resulted in the conveyance of new information to the requesting physician and/or a change in the patient's clinical plan. The very low percentage of such cases (0.058%) illustrates their rarity in daily practice, making it unlikely that manual identification/notification approaches alone can reliably manage them. The automated turnkey system was useful in avoiding missed handoffs of significant, clinically actionable diagnoses. PMID:22343338

  15. Evaluation and calibration of functional network modeling methods based on known anatomical connections.

    Science.gov (United States)

    Dawson, Debra Ann; Cha, Kuwook; Lewis, Lindsay B; Mendola, Janine D; Shmuel, Amir

    2013-02-15

    Recent studies have identified large scale brain networks based on the spatio-temporal structure of spontaneous fluctuations in resting-state fMRI data. It is expected that functional connectivity based on resting-state data is reflective of - but not identical to - the underlying anatomical connectivity. However, which functional connectivity analysis methods reliably predict the network structure remains unclear. Here we tested and compared network connectivity analysis methods by applying them to fMRI resting-state time-series obtained from the human visual cortex. The methods evaluated here are those previously tested against simulated data in Smith et al. (Neuroimage, 2011). To this end, we defined regions within retinotopic visual areas V1, V2, and V3 according to their eccentricity in the visual field, delineating central, intermediate, and peripheral eccentricity regions of interest (ROIs). These ROIs served as nodes in the models we study. We based our evaluation on the "ground-truth", thoroughly studied retinotopically-organized anatomical connectivity in the monkey visual cortex. For each evaluated method, we computed the fractional rate of detecting connections known to exist ("c-sensitivity"), while using a threshold of the 95th percentile of the distribution of interaction magnitudes of those connections not expected to exist. Under optimal conditions - including session duration of 68min, a relatively small network consisting of 9 nodes and artifact-free regression of the global effect - each of the top methods predicted the expected connections with 67-85% c-sensitivity. Correlation methods, including Correlation (Corr; 85%), Regularized Inverse Covariance (ICOV; 84%) and Partial Correlation (PCorr; 81%) performed best, followed by Patel's Kappa (80%), Bayesian Network method PC (BayesNet; 77%), General Synchronization measures (67-77%), and Coherence (CohB; 74%). With decreased session duration, these top methods saw decreases in c-sensitivities, achieving 59-76% for 17min sessions. With a short resting-state fMRI scan of 8.5min, none of the methods predicted the real network well, with Corr (65%) performing best. With increased complexity of the network from 9 to 36 nodes, multivariate methods including PCorr and BayesNet saw a decrease in performance. Artifact-free regression of the global effect increased the c-sensitivity of the top-performing methods. In an overall evaluation across all tests we performed, correlation methods (Corr, ICOV, and PCorr), Patel's Kappa, and BayesNet method PC set themselves somewhat above all other methods. We propose that data-based calibration based on known anatomical connections be integrated into future network studies, in order to maximize sensitivity and reduce false positives. PMID:23153969

  16. Parsing radiographs by integrating landmark set detection and multi-object active appearance models

    OpenAIRE

    Montillo, Albert; Song, Qi; LIU, XIAOMING; Miller, James V

    2013-01-01

    This work addresses the challenging problem of parsing 2D radiographs into salient anatomical regions such as the left and right lungs and the heart. We propose the integration of an automatic detection of a constellation of landmarks via rejection cascade classifiers and a learned geometric constellation subset detector model with a multi-object active appearance model (MO-AAM) initialized by the detected landmark constellation subset. Our main contribution is twofold. First, we propose a re...

  17. DETEKSI LANDMARK CITRA WAJAH DENGAN EXTRAKSI FITUR GABOR ANALISA FUZZY

    Directory of Open Access Journals (Sweden)

    Resmana Lim

    2003-01-01

    Full Text Available This paper proposes a method that automatically finds human faces as well as its landmark points in color images based on a fuzzy analysis. The proposed approach first uses color information to detect face candidate regions and then uses a fuzzy analysis of the color, shape, symmetry and interior facial features. A deformable Gabor wavelet graph matching is used to locate the facial landmark points describing the face. The latter allows for size and orientation variation since the search for landmark points allows for affine transformations as well as local deformations of the Gabor wavelet graph. The search is performed using a genetic algorithm that is essential because it effectively searches the solution space. Results based on the proposed method are included to verify the effectiveness of the proposed approach. Abstract in Bahasa Indonesia : Paper ini mengusulkan sebuah metode deteksi wajah beserta dengan titik landmarknya pada citra berwarna menggunakan analisa fuzzy. Proses awal menggunakan informasi warna kulit untuk menseleksi calon-calon obyek lantas dilanjukan dengan analisa fuzzy terhadap warna, bentuk, simetri dan fitur/landmark wajah. Proses lokalisasi landmark wajah menggunakan Gabor wavelet graph matching dengan memaksimalkan kemiripan antara landmark wajah model dengan obyek inputan. Proses maksimalisasi kemiripan ini menggunakan algoritma genetika. Hasil-hasil percobaan ditampilkan untuk memberikan gambaran keberhasilan dari metode yang diusulkan. Kata kunci: lokalisasi landmark wajah, analisa fuzzy, graph matching, algoritma genetika, Gabor wavelet.

  18. Describing head shapes of white stem borers (Schirpophaga innotata Walker that are able to survive on different rice types using Landmark based geometric morphometrics

    Directory of Open Access Journals (Sweden)

    Queenilyn B. Albutra

    2012-06-01

    Full Text Available Rice stem borers are considered as the most serious insect pest of rice in Asia. It infects itsplant host by burrowing into the stem using its mandible. However, apart from the mandible, the head ofrice stem borers is also associated in the incursion process since it facilitates the entry of larvae to the riceplant. Differences in the head capsules have a direct effect on the ability of the insects to ingest hardfoods rapidly. Different rice varieties in the Philippines serve as plant host for this pest and infestationoccurred in different geographical location. Variations in habitat and plant host were thought to generateenvironmental variation in morphometric traits and host adapted herbivore phenotype respectively.Landmark based geometric morphometric analysis was used to assess the hypothesis that the head shapeof white stem borer differ between populations with respect to different rice varieties and geographicallocation where it was obtained. Relative warp analysis showed variation in the head shape betweendifferent white stem borer (Schirpophaga innotata Walker populations infesting different varieties of rice.Non-significant head shape variations were obtained between geographically separated populations. Theseresults indicate that the rice host varieties play an important role in the selection of individuals that areable to counteract the resistance factors in plants.

  19. 3D facial landmarks: Inter-operator variability of manual annotation

    DEFF Research Database (Denmark)

    Fagertun, Jens; Harder, Stine

    2014-01-01

    Background Manual annotation of landmarks is a known source of variance, which exist in all fields of medical imaging, influencing the accuracy and interpretation of the results. However, the variability of human facial landmarks is only sparsely addressed in the current literature as opposed to e.g. the research fields of orthodontics and cephalometrics. We present a full facial 3D annotation procedure and a sparse set of manually annotated landmarks, in effort to reduce operator time and minimize the variance. Method Facial scans from 36 voluntary unrelated blood donors from the Danish Blood Donor Study was randomly chosen. Six operators twice manually annotated 73 anatomical and pseudo-landmarks, using a three-step scheme producing a dense point correspondence map. We analyzed both the intra- and inter-operator variability, using mixed-model ANOVA. We then compared four sparse sets of landmarks in order to construct a dense correspondence map of the 3D scans with a minimum point variance. Results The anatomical landmarks of the eye were associated with the lowest variance, particularly the center of the pupils. Whereas points of the jaw and eyebrows have the highest variation. We see marginal variability in regards to intra-operator and portraits. Using a sparse set of landmarks (n=14), that capture the whole face, the dense point mean variance was reduced from 1.92 to 0.54 mm. Conclusion The inter-operator variability was primarily associated with particular landmarks, where more leniently landmarks had the highest variability. The variables embedded in the portray and the reliability of a trained operator did only have marginal influence on the variability. Further, using 14 of the annotated landmarks we were able to reduced the variability and create a dense correspondences mesh to capture all facial features.

  20. 3D facial landmarks : Inter-operator variability of manual annotation

    DEFF Research Database (Denmark)

    Fagertun, Jens; Harder, Stine

    2014-01-01

    BACKGROUND: Manual annotation of landmarks is a known source of variance, which exist in all fields of medical imaging, influencing the accuracy and interpretation of the results. However, the variability of human facial landmarks is only sparsely addressed in the current literature as opposed to e.g. the research fields of orthodontics and cephalometrics. We present a full facial 3D annotation procedure and a sparse set of manually annotated landmarks, in effort to reduce operator time and minimize the variance. METHOD: Facial scans from 36 voluntary unrelated blood donors from the Danish Blood Donor Study was randomly chosen. Six operators twice manually annotated 73 anatomical and pseudo-landmarks, using a three-step scheme producing a dense point correspondence map. We analyzed both the intra- and inter-operator variability, using mixed-model ANOVA. We then compared four sparse sets of landmarks in order to construct a dense correspondence map of the 3D scans with a minimum point variance. RESULTS: The anatomical landmarks of the eye were associated with the lowest variance, particularly the center of the pupils. Whereas points of the jaw and eyebrows have the highest variation. We see marginal variability in regards to intra-operator and portraits. Using a sparse set of landmarks (n=14), that capture the whole face, the dense point mean variance was reduced from 1.92 to 0.54 mm. CONCLUSION: The inter-operator variability was primarily associated with particular landmarks, where more leniently landmarks had the highest variability. The variables embedded in the portray and the reliability of a trained operator did only have marginal influence on the variability. Further, using 14 of the annotated landmarks we were able to reduced the variability and create a dense correspondences mesh to capture all facial features.

  1. Landmarks GIScience for intelligent services

    CERN Document Server

    Richter, Kai-Florian

    2014-01-01

    This book covers the latest research on landmarks in GIS, including practical applications. It addresses perceptual and cognitive aspects of natural and artificial cognitive systems, computational aspects with respect to identifying or selecting landmarks for various purposes, and communication aspects of human-computer interaction for spatial information provision. Concise and organized, the book equips readers to handle complex conceptual aspects of trying to define and formally model these situations. The book provides a thorough review of the cognitive, conceptual, computational and commun

  2. The variability in the external rotation axis of the distal femur: an MRI-based anatomical study.

    Science.gov (United States)

    Jones, Carl; Nawaz, Zuhair; Hassan, Abdel; White, Simon; Khaleel, Arshad

    2016-02-01

    Commonly used total knee arthroplasty (TKA) systems utilising measured resection techniques default to 5°-7° valgus for the distal cut relative to the anatomical axis and 3° external rotation of the femoral component relative to posterior condylar axis (PCA). Rotational errors of the femoral component are associated with pain, patella maltracking and a poorer outcome. We analysed MRI scans from patients undergoing TKA using patient-specific instrumentation to assess coronal and rotational alignment from landmarks identified on the scans. One hundred and eight scans in 59 males and 49 females were studied with age range 35-93 years (mean 67.9 years). We found 91 % of patients had a femoral valgus angle between 5° and 7° (mean angles 5.9°), while only 24 % had an external rotation angle between 2.5° and 3.5° relative to PCA. There was no statistical significance in rotation between males and females although outliers tended to be female. Mean Whiteside's angle was 92.9° (87.8-98). This study highlights the variations in external rotation between patients undergoing TKA using the PCA as a reference for rotation. This may be a contributing factor in implant malalignment and patient dissatisfaction. PMID:26530410

  3. WE-D-9A-02: Automated Landmark-Guided CT to Cone-Beam CT Deformable Image Registration

    International Nuclear Information System (INIS)

    Purpose: The anatomical changes that occur between the simulation CT and daily cone-beam CT (CBCT) are investigated using an automated landmark-guided deformable image registration (LDIR) algorithm with simultaneous intensity correction. LDIR was designed to be accurate in the presence of tissue intensity mismatch and heavy noise contamination. Method: An auto-landmark generation algorithm was used in conjunction with a local small volume (LSV) gradient matching search engine to map corresponding landmarks between the CBCT and planning CT. The LSVs offsets were used to perform an initial deformation, generate landmarks, and correct local intensity mismatch. The landmarks act as stabilizing controlpoints in the Demons objective function. The accuracy of the LDIR algorithm was evaluated on one synthetic case with ground truth and data of ten head and neck cancer patients. The deformation vector field (DVF) accuracy was accessed using a synthetic case. The Root mean square error of the 3D canny edge (RMSECE), mutual information (MI), and feature similarity index metric (FSIM) were used to access the accuracy of LDIR on the patient data. The quality of the corresponding deformed contours was verified by an attending physician. Results: The resulting 90 percentile DVF error for the synthetic case was within 5.63mm for the original demons algorithm, 2.84mm for intensity correction alone, 2.45mm using controlpoints without intensity correction, and 1.48 mm for the LDIR algorithm. For the five patients the mean RMSECE of the original CT, Demons deformed CT, intensity corrected Demons CT, control-point stabilized deformed CT, and LDIR CT was 0.24, 0.26, 0.20, 0.20, and 0.16 respectively. Conclusion: LDIR is accurate in the presence of multimodal intensity mismatch and CBCT noise contamination. Since LDIR is GPU based it can be implemented with minimal additional strain on clinical resources. This project has been supported by a CPRIT individual investigator award RP11032

  4. An image processing system for locating craniofacial landmarks

    International Nuclear Information System (INIS)

    A new automatic target recognition algorithm has been developed to extract craniofacial landmarks from lateral skull x-rays (cephalograms). The locations of these landmarks are used by orthodontists in what is referred to as a cephalometric evaluation. The evaluation assists in the diagnosis of anomalies and in the monitoring of treatments. The algorithm is based on gray-scale mathematical morphology. A statistical approach to training was used to overcome subtle differences in skeletal topographies. Decomposition was used to desensitize the algorithm to size differences. A system was trained to locate 20 landmarks. Tests on 40 x-rays showed an 85% recognition rate on average

  5. Support vector machine-based classification of Alzheimer's disease from whole-brain anatomical MRI

    International Nuclear Information System (INIS)

    We present and evaluate a new automated method based on support vector machine (SVM) classification of whole-brain anatomical magnetic resonance imaging to discriminate between patients with Alzheimer's disease (AD) and elderly control subjects. We studied 16 patients with AD [mean age ± standard deviation (SD)=74.1 ±5.2 years, mini-mental score examination (MMSE) = 23.1 ± 2.9] and 22 elderly controls (72.3±5.0 years, MMSE=28.5± 1.3). Three-dimensional T1-weighted MR images of each subject were automatically parcellated into regions of interest (ROIs). Based upon the characteristics of gray matter extracted from each ROI, we used an SVM algorithm to classify the subjects and statistical procedures based on bootstrap resampling to ensure the robustness of the results. We obtained 94.5% mean correct classification for AD and control subjects (mean specificity, 96.6%; mean sensitivity, 91.5%). Our method has the potential in distinguishing patients with AD from elderly controls and therefore may help in the early diagnosis of AD. (orig.)

  6. Anatomical basis for the intrahepatic glissonian approach during hepatectomies / Bases anatômicas para o acesso intra-hepático aos pedículos glissonianos durante hepatectomias

    Scientific Electronic Library Online (English)

    Rodrigo Cañada Trofo, SURJAN; Fábio Ferrari, MAKDISSI; Marcel Autran Cesar, MACHADO.

    2015-06-01

    Full Text Available RACIONAL: Ressecções hepáticas anatômicas são baseadas em alguns princípios técnicos básicos, como o controle vascular, delimitação de área isquêmica a ser ressecada e máxima preservação do parênquima. Isto pode ser obtido pelo acesso intra-hepático aos pedículos glissonianos, que consiste em contr [...] ole dos pedículos dos segmentos dentro do parênquima hepático. Pequenas incisões ao redor da placa hilar, em marcos anatômicos bem definidos, são utilizadas para acesso aos pedículos, tornando desnecessária a dissecção do hilo hepático. OBJETIVO: Analisar parâmetros da anatomia do fígado relacionada com a técnica cirúrgica da abordagem intra-hepática aos pedículos glissonianos, para definir a anatomia normal relacionada ao procedimento e, assim, facilitar a realização desta técnica. MÉTODOS: Parâmetros anatômicos relacionados à abordagem intra-hepática aos pedículos glissonianos foram estudados em 37 cadáveres. As medições foram realizadas com instrumentos de precisão. Os dados foram expressos em média±desvio-padrão. Os indivíduos foram divididos em grupos de acordo com o sexo e peso do fígado e os grupos foram comparados estatisticamente. RESULTADOS: Vinte e cinco cadáveres eram do sexo masculino e 12 do feminino. Não houve diferença estatisticamente significativa em praticamente todos os parâmetros quando os grupos foram comparados. Isto demonstra a consistência dos parâmetros anatômicos relacionadas com a técnica intra-hepática de acesso glissoniano. CONCLUSÃO: Os resultados obtidos neste estudo possibilitaram grandes avanços técnicos na realização de hepatectomias abertas e laparoscópicas com abordagem intra-hepática aos pedículos glissonianos, e pode ajudar cirurgiões a realizar procedimentos seguros e eficazes por este método. Abstract in english BACKGROUND: Anatomical liver resections are based on some basic technical principles such as vascular control, ischemic area delineation to be resected and maximum parenchymal preservation. These aspects are achieved by the intrahepatic glissonian approach, which consists in accessing the pedicles [...] of hepatic segments within the hepatic parenchyma. Small incisions on well-defined anatomical landmarks are performed to approach the pedicles, making dissection of the hilar plate unnecessary. AIM: Analyze parameters in liver anatomy related to intrahepatic surgical technique to glissonians pedicles, to set the normal anatomy related to the procedure and thereby facilitate the attainment of this technique. METHODS: Anatomical parameters related to the intrahepatic glissonian approach were studied in 37 cadavers. Measurements were performed with precision instruments. Data were expressed as mean±standard deviation. The subjects were divided into groups according to gender and liver weight and groups were compared statistically. RESULTS: Twenty-five cadavers were male and 12 female. No statistically significant difference was observed in virtually all parameters when groups were compared. This demonstrates the consistency of the anatomical parameters related to the intrahepatic glissonian approach. CONCLUSION: The results obtained in this study made possible major technical advances in the realization of open and laparoscopic hepatectomies with intrahepatic glissonian approach, and can help surgeons to perform liver resections by this method.

  7. Detection of point landmarks in multidimensional tensor data?

    OpenAIRE

    Ruiz-Alzola, J.; Kikinis, R; Westin, C.-F.

    2001-01-01

    This paper describes a unified approach to the detection of point landmarks—whose neighborhoods convey discriminant information—including multidimensional scalar, vector, and higher-order tensor data. The method is based on the interpretation of generalized correlation matrices derived from the gradient of tensor functions, a probabilistic interpretation of point landmarks, and the application of tensor algebra. Results on both synthetic and real tensor data are presented.

  8. Visually-Guided Robot Navigation: From Artificial To Natural Landmarks

    OpenAIRE

    Celaya, Enric; Albarral García, José Luís; Jiménez Schlegl, Pablo; Torras, Carme

    2007-01-01

    Landmark-based navigation in unknown unstructured environments is far from solved. The bottleneck nowadays seems to be the fast detection of reliable visual references in the image stream as the robot moves. In our research, we have decoupled the navigation issues from this visual bottleneck, by first using artificial landmarks that could be easily detected and identified. Once we had a navigation system working, we developed a strategy to detect and track salient regions along image streams ...

  9. Quantitative modeling of the accuracy in registering preoperative patient-specific anatomic models into left atrial cardiac ablation procedures

    Energy Technology Data Exchange (ETDEWEB)

    Rettmann, Maryam E., E-mail: rettmann.maryam@mayo.edu; Holmes, David R.; Camp, Jon J.; Cameron, Bruce M.; Robb, Richard A. [Biomedical Imaging Resource, Mayo Clinic College of Medicine, Rochester, Minnesota 55905 (United States); Kwartowitz, David M. [Department of Bioengineering, Clemson University, Clemson, South Carolina 29634 (United States); Gunawan, Mia [Department of Biochemistry and Molecular and Cellular Biology, Georgetown University, Washington D.C. 20057 (United States); Johnson, Susan B.; Packer, Douglas L. [Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota 55905 (United States); Dalegrave, Charles [Clinical Cardiac Electrophysiology, Cardiology Division Hospital Sao Paulo, Federal University of Sao Paulo, 04024-002 Brazil (Brazil); Kolasa, Mark W. [David Grant Medical Center, Fairfield, California 94535 (United States)

    2014-02-15

    Purpose: In cardiac ablation therapy, accurate anatomic guidance is necessary to create effective tissue lesions for elimination of left atrial fibrillation. While fluoroscopy, ultrasound, and electroanatomic maps are important guidance tools, they lack information regarding detailed patient anatomy which can be obtained from high resolution imaging techniques. For this reason, there has been significant effort in incorporating detailed, patient-specific models generated from preoperative imaging datasets into the procedure. Both clinical and animal studies have investigated registration and targeting accuracy when using preoperative models; however, the effect of various error sources on registration accuracy has not been quantitatively evaluated. Methods: Data from phantom, canine, and patient studies are used to model and evaluate registration accuracy. In the phantom studies, data are collected using a magnetically tracked catheter on a static phantom model. Monte Carlo simulation studies were run to evaluate both baseline errors as well as the effect of different sources of error that would be present in a dynamicin vivo setting. Error is simulated by varying the variance parameters on the landmark fiducial, physical target, and surface point locations in the phantom simulation studies. In vivo validation studies were undertaken in six canines in which metal clips were placed in the left atrium to serve as ground truth points. A small clinical evaluation was completed in three patients. Landmark-based and combined landmark and surface-based registration algorithms were evaluated in all studies. In the phantom and canine studies, both target registration error and point-to-surface error are used to assess accuracy. In the patient studies, no ground truth is available and registration accuracy is quantified using point-to-surface error only. Results: The phantom simulation studies demonstrated that combined landmark and surface-based registration improved landmark-only registration provided the noise in the surface points is not excessively high. Increased variability on the landmark fiducials resulted in increased registration errors; however, refinement of the initial landmark registration by the surface-based algorithm can compensate for small initial misalignments. The surface-based registration algorithm is quite robust to noise on the surface points and continues to improve landmark registration even at high levels of noise on the surface points. Both the canine and patient studies also demonstrate that combined landmark and surface registration has lower errors than landmark registration alone. Conclusions: In this work, we describe a model for evaluating the impact of noise variability on the input parameters of a registration algorithm in the context of cardiac ablation therapy. The model can be used to predict both registration error as well as assess which inputs have the largest effect on registration accuracy.

  10. Quantitative modeling of the accuracy in registering preoperative patient-specific anatomic models into left atrial cardiac ablation procedures

    International Nuclear Information System (INIS)

    Purpose: In cardiac ablation therapy, accurate anatomic guidance is necessary to create effective tissue lesions for elimination of left atrial fibrillation. While fluoroscopy, ultrasound, and electroanatomic maps are important guidance tools, they lack information regarding detailed patient anatomy which can be obtained from high resolution imaging techniques. For this reason, there has been significant effort in incorporating detailed, patient-specific models generated from preoperative imaging datasets into the procedure. Both clinical and animal studies have investigated registration and targeting accuracy when using preoperative models; however, the effect of various error sources on registration accuracy has not been quantitatively evaluated. Methods: Data from phantom, canine, and patient studies are used to model and evaluate registration accuracy. In the phantom studies, data are collected using a magnetically tracked catheter on a static phantom model. Monte Carlo simulation studies were run to evaluate both baseline errors as well as the effect of different sources of error that would be present in a dynamicin vivo setting. Error is simulated by varying the variance parameters on the landmark fiducial, physical target, and surface point locations in the phantom simulation studies. In vivo validation studies were undertaken in six canines in which metal clips were placed in the left atrium to serve as ground truth points. A small clinical evaluation was completed in three patients. Landmark-based and combined landmark and surface-based registration algorithms were evaluated in all studies. In the phantom and canine studies, both target registration error and point-to-surface error are used to assess accuracy. In the patient studies, no ground truth is available and registration accuracy is quantified using point-to-surface error only. Results: The phantom simulation studies demonstrated that combined landmark and surface-based registration improved landmark-only registration provided the noise in the surface points is not excessively high. Increased variability on the landmark fiducials resulted in increased registration errors; however, refinement of the initial landmark registration by the surface-based algorithm can compensate for small initial misalignments. The surface-based registration algorithm is quite robust to noise on the surface points and continues to improve landmark registration even at high levels of noise on the surface points. Both the canine and patient studies also demonstrate that combined landmark and surface registration has lower errors than landmark registration alone. Conclusions: In this work, we describe a model for evaluating the impact of noise variability on the input parameters of a registration algorithm in the context of cardiac ablation therapy. The model can be used to predict both registration error as well as assess which inputs have the largest effect on registration accuracy

  11. Use of CT simulation for treatment of cervical cancer to assess the adequacy of lymph node coverage of conventional pelvic fields based on bony landmarks

    International Nuclear Information System (INIS)

    Purpose: To assess the adequacy of nodal coverage of 'conventional' pelvic radiation fields for carcinoma of the cervix, with contoured pelvic vessels on simulation computed tomography (CT) as surrogates for lymph node location. Methods and Materials: Pelvic arteries were contoured on non-contrast-enhanced CT simulation images of 43 patients with cervix cancer, FIGO Stages I-III. Vessel contours were hidden, and conventional pelvic fields were outlined: (1) anterior/posterior fields (AP): superior border, L5-S1 interspace; inferior border, obturator foramina; lateral border, 2 centimeters lateral to pelvic brim. (2) Lateral fields (LAT): Anterior border, symphysis pubis; posterior border, S2-S3 interspace. Distances were measured between the following: (1) bifurcation of the common iliac artery and superior border (2) external iliac artery and lateral border of the AP field, and (3) external iliac artery and anterior border of the LAT field. The distances were considered as 'inadequate' if 20 mm. Results: Superiorly, 34 patients (79.1%) had inadequate coverage. On the AP, margins were generous in 19 (44.2%), but inadequate in 9 (20.9%). On the LAT, margins were inadequate in 30 (69.8%) patients. Overall, 41 (95.4%, CI, 84.2%-99.4%) patients had at least 1 inadequate margin, the majority located superiorly. Twenty-four (55.8%; CI, 39.9%-70.9%) patients had at least 1 generous margin, the majority located laterally on the AP field. Conclusion: Conventional pelvic fields based on bony landmarks do not provide optimal lymph node coverage in a substantial proportion of patients and may include excess normal tissue in some. CT simulation with vessel contouring as a surrogate for lymph node localization provides more precise and individualized field delineation

  12. Landmarks or panoramas: what do navigating ants attend to for guidance?

    Directory of Open Access Journals (Sweden)

    Beugnon Guy

    2011-08-01

    Full Text Available Abstract Background Insects are known to rely on terrestrial landmarks for navigation. Landmarks are used to chart a route or pinpoint a goal. The distant panorama, however, is often thought not to guide navigation directly during a familiar journey, but to act as a contextual cue that primes the correct memory of the landmarks. Results We provided Melophorus bagoti ants with a huge artificial landmark located right near the nest entrance to find out whether navigating ants focus on such a prominent visual landmark for homing guidance. When the landmark was displaced by small or large distances, ant routes were affected differently. Certain behaviours appeared inconsistent with the hypothesis that guidance was based on the landmark only. Instead, comparisons of panoramic images recorded on the field, encompassing both landmark and distal panorama, could explain most aspects of the ant behaviours. Conclusion Ants navigating along a familiar route do not focus on obvious landmarks or filter out distal panoramic cues, but appear to be guided by cues covering a large area of their panoramic visual field, including both landmarks and distal panorama. Using panoramic views seems an appropriate strategy to cope with the complexity of natural scenes and the poor resolution of insects' eyes. The ability to isolate landmarks from the rest of a scene may be beyond the capacity of animals that do not possess a dedicated object-perception visual stream like primates.

  13. Effects of landmark distance and stability on accuracy of reward relocation.

    Science.gov (United States)

    Pritchard, David J; Hurly, T Andrew; Healy, Susan D

    2015-11-01

    Although small-scale navigation is well studied in a wide range of species, much of what is known about landmark use by vertebrates is based on laboratory experiments. To investigate how vertebrates in the wild use landmarks, we trained wild male rufous hummingbirds to feed from a flower that was placed in a constant spatial relationship with two artificial landmarks. In the first experiment, the landmarks and flower were 0.25, 0.5 or 1 m apart and we always moved them 3-4 m after each visit by the bird. In the second experiment, the landmarks and flower were always 0.25 m apart and we moved them either 1 or 0.25 m between trials. In tests, in which we removed the flower, the hummingbirds stopped closer to the predicted flower location when the landmarks had been closer to the flower during training. However, while the distance that the birds stopped from the landmarks and predicted flower location was unaffected by the distance that the landmarks moved between trials, the birds directed their search nearer to the predicted direction of the flower, relative to the landmarks, when the landmarks and flower were more stable in the environment. In the field, then, landmarks alone were sufficient for the birds to determine the distance of a reward but not its direction. PMID:26198691

  14. MIDA: A Multimodal Imaging-Based Detailed Anatomical Model of the Human Head and Neck.

    Science.gov (United States)

    Iacono, Maria Ida; Neufeld, Esra; Akinnagbe, Esther; Bower, Kelsey; Wolf, Johanna; Vogiatzis Oikonomidis, Ioannis; Sharma, Deepika; Lloyd, Bryn; Wilm, Bertram J; Wyss, Michael; Pruessmann, Klaas P; Jakab, Andras; Makris, Nikos; Cohen, Ethan D; Kuster, Niels; Kainz, Wolfgang; Angelone, Leonardo M

    2015-01-01

    Computational modeling and simulations are increasingly being used to complement experimental testing for analysis of safety and efficacy of medical devices. Multiple voxel- and surface-based whole- and partial-body models have been proposed in the literature, typically with spatial resolution in the range of 1-2 mm and with 10-50 different tissue types resolved. We have developed a multimodal imaging-based detailed anatomical model of the human head and neck, named "MIDA". The model was obtained by integrating three different magnetic resonance imaging (MRI) modalities, the parameters of which were tailored to enhance the signals of specific tissues: i) structural T1- and T2-weighted MRIs; a specific heavily T2-weighted MRI slab with high nerve contrast optimized to enhance the structures of the ear and eye; ii) magnetic resonance angiography (MRA) data to image the vasculature, and iii) diffusion tensor imaging (DTI) to obtain information on anisotropy and fiber orientation. The unique multimodal high-resolution approach allowed resolving 153 structures, including several distinct muscles, bones and skull layers, arteries and veins, nerves, as well as salivary glands. The model offers also a detailed characterization of eyes, ears, and deep brain structures. A special automatic atlas-based segmentation procedure was adopted to include a detailed map of the nuclei of the thalamus and midbrain into the head model. The suitability of the model to simulations involving different numerical methods, discretization approaches, as well as DTI-based tensorial electrical conductivity, was examined in a case-study, in which the electric field was generated by transcranial alternating current stimulation. The voxel- and the surface-based versions of the models are freely available to the scientific community. PMID:25901747

  15. Mapped Landmark Algorithm for Precision Landing

    Science.gov (United States)

    Johnson, Andrew; Ansar, Adnan; Matthies, Larry

    2007-01-01

    A report discusses a computer vision algorithm for position estimation to enable precision landing during planetary descent. The Descent Image Motion Estimation System for the Mars Exploration Rovers has been used as a starting point for creating code for precision, terrain-relative navigation during planetary landing. The algorithm is designed to be general because it handles images taken at different scales and resolutions relative to the map, and can produce mapped landmark matches for any planetary terrain of sufficient texture. These matches provide a measurement of horizontal position relative to a known landing site specified on the surface map. Multiple mapped landmarks generated per image allow for automatic detection and elimination of bad matches. Attitude and position can be generated from each image; this image-based attitude measurement can be used by the onboard navigation filter to improve the attitude estimate, which will improve the position estimates. The algorithm uses normalized correlation of grayscale images, producing precise, sub-pixel images. The algorithm has been broken into two sub-algorithms: (1) FFT Map Matching (see figure), which matches a single large template by correlation in the frequency domain, and (2) Mapped Landmark Refinement, which matches many small templates by correlation in the spatial domain. Each relies on feature selection, the homography transform, and 3D image correlation. The algorithm is implemented in C++ and is rated at Technology Readiness Level (TRL) 4.

  16. PACS-based interface for 3D anatomical structure visualization and surgical planning

    Science.gov (United States)

    Koehl, Christophe; Soler, Luc; Marescaux, Jacques

    2002-05-01

    The interpretation of radiological image is routine but it remains a rather difficult task for physicians. It requires complex mental processes, that permit translation from 2D slices into 3D localization and volume determination of visible diseases. An easier and more extensive visualization and exploitation of medical images can be reached through the use of computer-based systems that provide real help from patient admission to post-operative followup. In this way, we have developed a 3D visualization interface linked to a PACS database that allows manipulation and interaction on virtual organs delineated from CT-scan or MRI. This software provides the 3D real-time surface rendering of anatomical structures, an accurate evaluation of volumes and distances and the improvement of radiological image analysis and exam annotation through a negatoscope tool. It also provides a tool for surgical planning allowing the positioning of an interactive laparoscopic instrument and the organ resection. The software system could revolutionize the field of computerized imaging technology. Indeed, it provides a handy and portable tool for pre-operative and intra-operative analysis of anatomy and pathology in various medical fields. This constitutes the first step of the future development of augmented reality and surgical simulation systems.

  17. Anatomical bases for the radiological delineation of lymph node areas. Major collecting trunks, head and neck

    International Nuclear Information System (INIS)

    Cancer spreads locally through direct infiltration into soft tissues or at distance by invading vascular structures, then migrating through the lymphatic or blood flow. Although cancer cells carried in the blood can end in virtually any corner of the body, lymphatic migration is usually stepwise, through successive nodal stops, which can temporarily delay further progression. In radiotherapy, irradiation of lymphatic paths relevant to the localisation of the primary has been common practice for decades. Similarly, excision of cancer is often completed by lymphatic dissection. Both in radiotherapy and in surgery, advanced knowledge of the lymphatic pathways relevant to any tumor location is an important information for treatment preparation and execution. This first part describes the major collecting trunks of the lymphatic system and then the lymphatics of the head and neck providing anatomical bases for the radiological delineation of lymph node areas in the cervical region, it adds to the existing nomenclature of six nodal levels (I-VI), three new areas listed as parotid, buccal and external jugular levels

  18. Identification keys on rattans (Calamus spp. from Central Sulawesi based on anatomical structure of stems

    Directory of Open Access Journals (Sweden)

    ANDI TANRA TELLU

    2005-04-01

    Full Text Available This study was conducted to obtain information the anatomical characteristics of 20 rattan species from Central Sulawesi and to use it for anatomical identification of rattan species. The rattan comprised 16 Calamus species, three Daemonorops species and one Korthalsia species. For anatomical observation 10-15 mm pieces of the mature stem from shares of tip do not have frond were processed with polyethilene glycol 2000, cut at 18-32 µm and stained with a combination of acridin-cryzoidin red and astrablue. Cleared preparation were used to observe stegmata, and macerated material was used to measure the length of fibers and vessel elements. Anilin sulfate was used to confirm the existence of lignin. Anatomical characteristics used in identification were shape and will thickening of epidermal cells and the position stomata at epidermal; the arrangement of sub epidermal parenchyma; composition of vascular bundles and their distribution; the shape and arrangement of central ground parenchyma and the occurrence of fiber bundles. The research result indicated that the anatomical character can be compiled to a key identify the rattan at genus and species level.

  19. ANATOMICAL PRINCIPLES BEHIND PRESERVATION OF LARYNGEAL NERVES DURING THYROIDECTOMY

    Directory of Open Access Journals (Sweden)

    O. Fabian

    2011-08-01

    Full Text Available This paper presents the anatomical principles behind preservation of inferior laryngeal nerve and of the external branch of superior laryngeal nerve during thyroidectomy. The embryological development of thyroid and recurrent laryngeal nerves explains the constant relationship between Zuckerkandl’s tuberculum and the recurrent laryngeal nerve, while anomalies in development of the aortic arches explain the presence of rare anatomical variants, with a high risk of nerve injury, of non-recurrent course of the inferior laryngeal nerve. Good knowledge of the relationship between the external branch of superior laryngeal nerve and the superior thyroid artery makes possible to avoid transection of this branch during ligature around superior thyroid artery and vein. Anatomical landmarks used to identify the recurrent laryngeal nerve (tracheo-oesophageal sulcus, the cross-over with the inferior thyroid artery, Berry’s ligament, Zuckerkandl’s tuberculum and variations in the extra-laryngeal branching of the nerve are discussed based on data from the literature. The anatomical variants when the inferior laryngeal nerve doesn’t have a recurrent course are also discussed

  20. 3D facial landmarks: Inter-operator variability of manual annotation

    DEFF Research Database (Denmark)

    Fagertun, Jens; Harder, Stine; Rosengren, Anders; Møller, Christian; Werge, Thomas; Paulsen, Rasmus Reinhold; Hansen, Thomas Fritz

    2014-01-01

    Donor Study was randomly chosen. Six operators twice manually annotated 73 anatomical and pseudo-landmarks, using a three-step scheme producing a dense point correspondence map. We analyzed both the intra- and inter-operator variability, using mixed-model ANOVA. We then compared four sparse sets of......Background Manual annotation of landmarks is a known source of variance, which exist in all fields of medical imaging, influencing the accuracy and interpretation of the results. However, the variability of human facial landmarks is only sparsely addressed in the current literature as opposed to e.......g. the research fields of orthodontics and cephalometrics. We present a full facial 3D annotation procedure and a sparse set of manually annotated landmarks, in effort to reduce operator time and minimize the variance. Method Facial scans from 36 voluntary unrelated blood donors from the Danish Blood...

  1. Landmark Discrimination Learning in the Dog

    OpenAIRE

    Milgram, Norton W.; Adams, Beth; Callahan, Heather; Head, Elizabeth; Mackay, Bill; Thirlwell, Celeste; Cotman, Carl W

    1999-01-01

    Allocentric spatial memory was studied in dogs of varying ages and sources using a landmark discrimination task. The primary goal of this study was to develop a protocol to test landmark discrimination learning in the dog. Using a modified version of a landmark test developed for use in monkeys, we successfully trained dogs to make a spatial discrimination on the basis of the position of a visual landmark relative to two identical discriminanda. Task performance decreased, however, as the dis...

  2. Free-space fluorescence tomography with adaptive sampling based on anatomical information from microCT

    Science.gov (United States)

    Zhang, Xiaofeng; Badea, Cristian T.; Hood, Greg; Wetzel, Arthur W.; Stiles, Joel R.; Johnson, G. Allan

    2010-02-01

    Image reconstruction is one of the main challenges for fluorescence tomography. For in vivo experiments on small animals, in particular, the inhomogeneous optical properties and irregular surface of the animal make free-space image reconstruction challenging because of the difficulties in accurately modeling the forward problem and the finite dynamic range of the photodetector. These two factors are fundamentally limited by the currently available forward models and photonic technologies. Nonetheless, both limitations can be significantly eased using a signal processing approach. We have recently constructed a free-space panoramic fluorescence diffuse optical tomography system to take advantage of co-registered microCT data acquired from the same animal. In this article, we present a data processing strategy that adaptively selects the optical sampling points in the raw 2-D fluorescent CCD images. Specifically, the general sampling area and sampling density are initially specified to create a set of potential sampling points sufficient to cover the region of interest. Based on 3-D anatomical information from the microCT and the fluorescent CCD images, data points are excluded from the set when they are located in an area where either the forward model is known to be problematic (e.g., large wrinkles on the skin) or where the signal is unreliable (e.g., saturated or low signal-to-noise ratio). Parallel Monte Carlo software was implemented to compute the sensitivity function for image reconstruction. Animal experiments were conducted on a mouse cadaver with an artificial fluorescent inclusion. Compared to our previous results using a finite element method, the newly developed parallel Monte Carlo software and the adaptive sampling strategy produced favorable reconstruction results.

  3. Geodesic atlas-based labeling of anatomical trees : Application and evaluation on airways extracted from CT

    DEFF Research Database (Denmark)

    Feragen, Aasa; Petersen, Jens

    2015-01-01

    We present a fast and robust atlas-based algorithm for labeling airway trees, using geodesic distances in a geometric tree-space. Possible branch label configurations for an unlabeled airway tree are evaluated using distances to a training set of labeled airway trees. In tree-space, airway tree topology and geometry change continuously, giving a natural automatic handling of anatomical differences and noise. A hierarchical approach makes the algorithm efficient, assigning labels from the trachea and downwards. Only the airway centerline tree is used, which is relatively unaffected by pathology. The algorithm is evaluated on 80 segmented airway trees from 40 subjects at two time points, labeled by 3 medical experts each, testing accuracy, reproducibility and robustness in patients with Chronic Obstructive Pulmonary Disease (COPD). The accuracy of the algorithm is statistically similar to that of the experts and not significantly correlated with COPD severity. The reproducibility of the algorithm is significantly better than that of the experts, and negatively correlated with COPD severity. Evaluation of the algorithm on a longitudinal set of 8724 trees from a lung cancer screening trial shows that the algorithm can be used in large scale studies with high reproducibility, and that the negative correlation of reproducibility with COPD severity can be explained by missing branches, for instance due to segmentation problems in COPD patients. We conclude that the algorithm is robust to COPD severity given equally complete airway trees, and comparable in performance to that of experts in pulmonary medicine, emphasizing the suitability of the labeling algorithm for clinical use.

  4. Geodesic atlas-based labeling of anatomical trees : application and evaluation on airways extracted from CT

    DEFF Research Database (Denmark)

    Feragen, Aasa; Petersen, Jens

    2015-01-01

    We present a fast and robust atlas-based algorithm for labeling airway trees, using geodesic distances in a geometric tree-space. Possible branch label configurations for an unlabeled airway tree are evaluated using distances to a training set of labeled airway trees. In tree-space, airway tree topology and geometry change continuously, giving a natural automatic handling of anatomical differences and noise. A hierarchical approach makes the algorithm efficient, assigning labels from the trachea and downwards. Only the airway centerline tree is used, which is relatively unaffected by pathology. The algorithm is evaluated on 80 segmented airway trees from 40 subjects at two time points, labeled by 3 medical experts each, testing accuracy, reproducibility and robustness in patients with Chronic Obstructive Pulmonary Disease (COPD). The accuracy of the algorithm is statistically similar to that of the experts and not significantly correlated with COPD severity. The reproducibility of the algorithm is significantly better than that of the experts, and negatively correlated with COPD severity. Evaluation of the algorithm on a longitudinal set of 8724 trees from a lung cancer screening trial shows that the algorithm can be used in large scale studies with high reproducibility, and that the negative correlation of reproducibility with COPD severity can be explained by missing branches, for instance due to segmentation problems in COPD patients. We conclude that the algorithm is robust to COPD severity given equally complete airway trees, and comparable in performance to that of experts in pulmonary medicine, emphasizing the suitability of the labeling algorithm for clinical use.

  5. 75 FR 69120 - National Natural Landmark Designations

    Science.gov (United States)

    2010-11-10

    ... National Natural Landmark Designations AGENCY: National Park Service, Department of the Interior. ACTION: Public Notice of National Natural Landmark Designations. SUMMARY: On January 16, 2009, then Secretary of the Interior Dirk Kempthorne designated the following National Natural Landmarks: Big Bone Lick,...

  6. Acquistion of Structural versus Object Landmark Knowledge

    Science.gov (United States)

    Stankiewicz, Brian J.; Kalia, Amy A.

    2007-01-01

    Three experiments investigated the acquisition and retention of structural and object landmarks in virtual indoor environments. The experiments investigated the rate of acquisition and memory retention for hallway structure (structural landmarks) and pictures (object landmarks). The experiments investigated the rate of acquisition, the role of…

  7. 23 CFR 750.710 - Landmark signs.

    Science.gov (United States)

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Landmark signs. 750.710 Section 750.710 Highways FEDERAL... Outdoor Advertising Control § 750.710 Landmark signs. (a) 23 U.S.C. 131(c) permits the existence of signs... Secretary, to be landmark signs, including signs on farm structures or natural surfaces, of historic...

  8. Bases anatómicas vasculares de los colgajos perforantes cutáneos / Vascular anatomical basis of perforator skin flaps

    Scientific Electronic Library Online (English)

    S., Morris; M., Tang; C.R., Geddes.

    2006-12-01

    Full Text Available En las ultimas dos décadas, el uso de colgajos perforantes musculocutaneos se ha incrementado a medida que los microcirujanos se han familiarizado con la técnica y estos colgajos se han convertido en una parte de la evolución de la Microcirugía. Como se basan en perforantes musculocutaneas o septocu [...] taneas individuales, el microcirujano reconstructivodebe tener la información anatómica detallada para planificar la transferencia de colgajos perforantes. El fin de este trabajo es la revisión de las diversas técnicas angiográficas disponibles para estudiar la anatomía vascular del cuerpo humano y presentar nuestra técnica habitual de inyección vascular. Exhibiremos ejemplos ilustrativos utilizando la técnica de la inyección de gelatina de oxido de plomo para visualizar la anatomía relevante de los sitios donantes de colgajos perforantes. La técnica de la inyección de gelatina de óxido descrita por Salmon y Rees y Taylor, puede ser utilizada para inyecciones arteriales o venosas, pero la hemos utilizado primariamente para inyección arterial. Los pasos para la inyección se describen detalladamente en el trabajo. En los pasados 5 años hemos disecado un total de 21 cadáveres frescos tras estudios de inyección arterial de gelatina de oxido de plomo. Se han revisado un total de 7000 radiografías. Presentamos los resultados de la búsqueda anatómica en las áreas de cabeza, cuello, miembros superiores, torso y miembros inferiores. La técnica de la inyección de gelatina de oxido de plomo es simple y económica a su vez; la técnica de análisis computarizado es barata y las técnicas de análisis informático son directas y proveen excelente visualización de la arquitectura de la piel humana. Los delicados detalles identificados utilizando esta técnica de inyección proveen información útil a los cirujanos para planificar transferencias de piel, músculo, hueso y nervio, y por tanto favorecen nuestra comprensión de la anatomía vascular clínicamente relacionada de los colgajos perforantes. Abstract in english Over the past 2 decades the use of musculocutaneous perforator flaps has increased worldwide as microsurgeons have become more comfortable with the technique. Perforator flaps have now become well established as a part of the evolution of microsurgery. Since perforator flaps are based on individual [...] musculocutaneous or septocutaneous perforators, it is imperative that the reconstructive microsurgeon has the detailed anatomical information necessary to plan perforator flap transfers. The goal of this paper is to review the various angiographic techniques which are available to study the vascular anatomy of the human body and to present our current vascular injection technique. We will show illustrative examples using the lead oxide gelatin injection technique to elucidate the relevant anatomy of perforator flap donor sites. The lead oxide gelatin injection technique has been previously reported by Salmon and Rees and Taylor. The injection technique may be used for arterial or venous injections but we have primarily used it for arterial injections. The injection steps are detailed in the paper. Over the past five years we have dissected a total of 21 human fresh cadavers after lead oxide gelatin arterial injection studies. A total of over 7000 radiographs have been reviewed and summarized. We present summarized results of the anatomical research in the areas of head and neck, upper limb, torso and lower limb regions. The lead oxide gelatin injection technique is simple and inexpensive and the computer analysis technique is straight forward and provides excellent visualization of the architecture of the human skin. The fine details identified using this injection technique provides useful information to surgeons planning transfers of skin, muscle, bone and nerve and therefore our understandingly of clinically related vascular anatomy of perforator flaps can be improved.

  9. Bases anatómicas vasculares de los colgajos perforantes cutáneos Vascular anatomical basis of perforator skin flaps

    Directory of Open Access Journals (Sweden)

    S. Morris

    2006-12-01

    Full Text Available En las ultimas dos décadas, el uso de colgajos perforantes musculocutaneos se ha incrementado a medida que los microcirujanos se han familiarizado con la técnica y estos colgajos se han convertido en una parte de la evolución de la Microcirugía. Como se basan en perforantes musculocutaneas o septocutaneas individuales, el microcirujano reconstructivodebe tener la información anatómica detallada para planificar la transferencia de colgajos perforantes. El fin de este trabajo es la revisión de las diversas técnicas angiográficas disponibles para estudiar la anatomía vascular del cuerpo humano y presentar nuestra técnica habitual de inyección vascular. Exhibiremos ejemplos ilustrativos utilizando la técnica de la inyección de gelatina de oxido de plomo para visualizar la anatomía relevante de los sitios donantes de colgajos perforantes. La técnica de la inyección de gelatina de óxido descrita por Salmon y Rees y Taylor, puede ser utilizada para inyecciones arteriales o venosas, pero la hemos utilizado primariamente para inyección arterial. Los pasos para la inyección se describen detalladamente en el trabajo. En los pasados 5 años hemos disecado un total de 21 cadáveres frescos tras estudios de inyección arterial de gelatina de oxido de plomo. Se han revisado un total de 7000 radiografías. Presentamos los resultados de la búsqueda anatómica en las áreas de cabeza, cuello, miembros superiores, torso y miembros inferiores. La técnica de la inyección de gelatina de oxido de plomo es simple y económica a su vez; la técnica de análisis computarizado es barata y las técnicas de análisis informático son directas y proveen excelente visualización de la arquitectura de la piel humana. Los delicados detalles identificados utilizando esta técnica de inyección proveen información útil a los cirujanos para planificar transferencias de piel, músculo, hueso y nervio, y por tanto favorecen nuestra comprensión de la anatomía vascular clínicamente relacionada de los colgajos perforantes.Over the past 2 decades the use of musculocutaneous perforator flaps has increased worldwide as microsurgeons have become more comfortable with the technique. Perforator flaps have now become well established as a part of the evolution of microsurgery. Since perforator flaps are based on individual musculocutaneous or septocutaneous perforators, it is imperative that the reconstructive microsurgeon has the detailed anatomical information necessary to plan perforator flap transfers. The goal of this paper is to review the various angiographic techniques which are available to study the vascular anatomy of the human body and to present our current vascular injection technique. We will show illustrative examples using the lead oxide gelatin injection technique to elucidate the relevant anatomy of perforator flap donor sites. The lead oxide gelatin injection technique has been previously reported by Salmon and Rees and Taylor. The injection technique may be used for arterial or venous injections but we have primarily used it for arterial injections. The injection steps are detailed in the paper. Over the past five years we have dissected a total of 21 human fresh cadavers after lead oxide gelatin arterial injection studies. A total of over 7000 radiographs have been reviewed and summarized. We present summarized results of the anatomical research in the areas of head and neck, upper limb, torso and lower limb regions. The lead oxide gelatin injection technique is simple and inexpensive and the computer analysis technique is straight forward and provides excellent visualization of the architecture of the human skin. The fine details identified using this injection technique provides useful information to surgeons planning transfers of skin, muscle, bone and nerve and therefore our understandingly of clinically related vascular anatomy of perforator flaps can be improved.

  10. All that Glitters is not Gold: Using Landmarks for Reward Shaping in FPG

    OpenAIRE

    Buffet, Olivier; Hoffmann, Joerg

    2010-01-01

    Landmarks are facts that must be true at some point in any plan. It has recently been proposed in classical planning to use landmarks for the automatic generation of heuristic functions. We herein apply this idea in probabilistic planning. We focus on the FPG tool, which derives a factored policy based on learning from samples into the state space. The rationale is that FPG's performance can be improved significantly by a trivial heuristic that counts the number of false goals; landmarks prov...

  11. "Localization Space" : a framework for localization and planning, for systems using a Sensor/Landmarks module

    OpenAIRE

    Pradalier, Cédric; Sekhavat, Sepanta

    2002-01-01

    One of the common ways of localization in robotics is the triangulation using a system composed of a sensor and some landmarks (which can be artificial or natural). This paper presents a framework, namely the Localization Space, in order to deal with problems such as the landmark placement and motion planning including the localization constraint. Based on this framework, we present general approaches to the optimal distribution of the landmarks or to the computation of reliable trajectories....

  12. A study on the reproducibility of cephalometric landmarks when undertaking a three-dimensional (3D) cephalometric analysis

    OpenAIRE

    Zamora, Natalia; Llamas, José M.; Cibrián, Rosa; Gandia, José L.; Paredes, Vanessa

    2012-01-01

    Objectives: Cone Beam Computerized Tomography (CBCT) allows the possibility of modifying some of the diagnostic tools used in orthodontics, such as cephalometry. The first step must be to study the characteristics of these devices in terms of accuracy and reliability of the most commonly used landmarks. The aims were 1- To assess intra and inter-observer reliability in the location of anatomical landmarks belonging to hard tissues of the skull in images taken with a CBCT device, 2- To determi...

  13. 36 CFR 62.6 - Natural landmark monitoring.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Natural landmark monitoring... INTERIOR NATIONAL NATURAL LANDMARKS PROGRAM § 62.6 Natural landmark monitoring. (a) Owner contact. The... landmarks to determine whether the landmarks retain the values that qualified them for landmark...

  14. Geographic Surveillance - Landmark Studies

    Science.gov (United States)

    SEER is an authoritative source of information on cancer incidence and survival in the United States. SEER currently collects and publishes cancer incidence and survival data from population-based cancer registries covering approximately 28 percent of the U.S. population.

  15. Anatomic-Based Three-Dimensional Planning Precludes Use of Catheter-Delivered Contrast for Treatment of Prostate Cancer

    International Nuclear Information System (INIS)

    Purpose: Retrograde urethrography is a standard method to identify the prostatic apex during planning for prostate cancer radiotherapy. This is an invasive and uncomfortable procedure. With modern three-dimensional computed tomography planning, we explored whether retrograde urethrography was still necessary to accurately identify the prostatic apex. Methods and Materials: Fifteen patients underwent computed tomography simulation with and without bladder, urethral, and rectal contrast. The prostatic base and apex were identified on both scans, using contrast and anatomy, respectively. The anatomic location of the prostatic apex as defined by these methods was confirmed in another 57 patients with postbrachytherapy imaging. Results: The prostatic base and apex were within a mean of 3.8 mm between the two scans. In every case, the beak of the retrograde urethrogram abutted the line drawn parallel to, and bisecting, the pubic bone on the lateral films. With these anatomic relationships defined, in the postbrachytherapy patients, the distance from the prostatic apex to the point at which the urethra traversed the pelvic floor was an average of 11.7 mm. On lateral films, we found that the urethra exited the pelvis an average of 16.6 mm below the posterior-most fusion of the pubic symphysis. On axial images, this occurred at a mean separation of the ischia of about 25 mm. Conclusion: With a knowledge of the anatomic relationships and modern three-dimensional computed tomography planning equipment, the prostatic apex can be easily and consistently identified, obviating the need to subject patients to retrograde urethrography

  16. Anatomical-based partial volume correction for low-dose dedicated cardiac SPECT/CT

    Science.gov (United States)

    Liu, Hui; Chan, Chung; Grobshtein, Yariv; Ma, Tianyu; Liu, Yaqiang; Wang, Shi; Stacy, Mitchel R.; Sinusas, Albert J.; Liu, Chi

    2015-09-01

    Due to the limited spatial resolution, partial volume effect has been a major degrading factor on quantitative accuracy in emission tomography systems. This study aims to investigate the performance of several anatomical-based partial volume correction (PVC) methods for a dedicated cardiac SPECT/CT system (GE Discovery NM/CT 570c) with focused field-of-view over a clinically relevant range of high and low count levels for two different radiotracer distributions. These PVC methods include perturbation geometry transfer matrix (pGTM), pGTM followed by multi-target correction (MTC), pGTM with known concentration in blood pool, the former followed by MTC and our newly proposed methods, which perform the MTC method iteratively, where the mean values in all regions are estimated and updated by the MTC-corrected images each time in the iterative process. The NCAT phantom was simulated for cardiovascular imaging with 99mTc-tetrofosmin, a myocardial perfusion agent, and 99mTc-red blood cell (RBC), a pure intravascular imaging agent. Images were acquired at six different count levels to investigate the performance of PVC methods in both high and low count levels for low-dose applications. We performed two large animal in vivo cardiac imaging experiments following injection of 99mTc-RBC for evaluation of intramyocardial blood volume (IMBV). The simulation results showed our proposed iterative methods provide superior performance than other existing PVC methods in terms of image quality, quantitative accuracy, and reproducibility (standard deviation), particularly for low-count data. The iterative approaches are robust for both 99mTc-tetrofosmin perfusion imaging and 99mTc-RBC imaging of IMBV and blood pool activity even at low count levels. The animal study results indicated the effectiveness of PVC to correct the overestimation of IMBV due to blood pool contamination. In conclusion, the iterative PVC methods can achieve more accurate quantification, particularly for low count cardiac SPECT studies, typically obtained from low-dose protocols, gated studies, and dynamic applications.

  17. Evaluation of contrast reproduction method based on the anatomical guidance of the cerebral images reconstruction in positron emission tomography

    International Nuclear Information System (INIS)

    Positron emission tomography is a medical imaging modality providing in-vivo volumetric images of functional processes of the human body, which is used for the diagnosis and the following of neuro degenerative diseases. PET efficiency is however limited by its poor spatial resolution, which generates a decrease of the image local contrast and leads to an under-estimation of small cerebral structures involved in the degenerative mechanism of those diseases. This so-called partial volume effect degradation is usually corrected in a post-reconstruction processing framework through the use of anatomical information, whose spatial resolution allows a better discrimination between functional tissues. However, this kind of method has the major drawback of being very sensitive to the residual mismatches on the anatomical information processing. We developed in this thesis an alternative methodology to compensate for the degradation, by incorporating in the reconstruction process both a model of the system impulse response and an anatomically-based image prior constraint. This methodology was validated by comparison with a post-reconstruction correction strategy, using data from an anthropomorphic phantom acquisition and then we evaluated its robustness to the residual mismatches through a realistic Monte Carlo simulation corresponding to a cerebral exam. The proposed algorithm was finally applied to clinical data reconstruction. (author)

  18. Diversity analysis of mangosteen (Garcinia mangostana irradiated by gamma-ray based on morphological and anatomical characteristics

    Directory of Open Access Journals (Sweden)

    MUH RAHMAD SUHARTANTO

    2010-01-01

    Full Text Available Widiastuti A, Sobir, Suhartanto MR. 2010. Diversity analysis of mangosteen (Garcinia mangostana L. irradiated by gamma-ray based on morphological and anatomical characteristics. Nusantara Bioscience 2: 23-33. The aim of this research was to increase genetic variability of mangosteen (Garcinia mangostana L. irradiated by gamma rays dosage of 0 Gy, 20 Gy, 25 Gy, 30 Gy,35 Gy and 40 Gy. Plant materials used were seeds collected from Cegal Sub-village, Karacak Village, Leuwiliang Sub-district, Bogor District, West Java. Data was generated from morphological and anatomical characteristics. The result indicated that increasing of gamma ray dosage had inhibited ability of seed to growth, which needed longer time and decreased seed viability. Morphologically, it also decreased plant heigh, stem diameter, leaf seizure, and amount of leaf. Anatomically, stomatal density had positive correlation with plant height by correlation was 90% and 74%. Gamma rays irradiation successfully increase morphological variability until 30%. Seed creavage after irradiation increased variability and survival rate of mangosteen.

  19. Model-based dose calculations for COMS eye plaque brachytherapy using an anatomically realistic eye phantom

    Energy Technology Data Exchange (ETDEWEB)

    Lesperance, Marielle; Inglis-Whalen, M.; Thomson, R. M., E-mail: rthomson@physics.carleton.ca [Carleton Laboratory for Radiotherapy Physics, Department of Physics, Carleton University, Ottawa K1S 5B6 (Canada)

    2014-02-15

    Purpose : To investigate the effects of the composition and geometry of ocular media and tissues surrounding the eye on dose distributions for COMS eye plaque brachytherapy with{sup 125}I, {sup 103}Pd, or {sup 131}Cs seeds, and to investigate doses to ocular structures. Methods : An anatomically and compositionally realistic voxelized eye model with a medial tumor is developed based on a literature review. Mass energy absorption and attenuation coefficients for ocular media are calculated. Radiation transport and dose deposition are simulated using the EGSnrc Monte Carlo user-code BrachyDose for a fully loaded COMS eye plaque within a water phantom and our full eye model for the three radionuclides. A TG-43 simulation with the same seed configuration in a water phantom neglecting the plaque and interseed effects is also performed. The impact on dose distributions of varying tumor position, as well as tumor and surrounding tissue media is investigated. Each simulation and radionuclide is compared using isodose contours, dose volume histograms for the lens and tumor, maximum, minimum, and average doses to structures of interest, and doses to voxels of interest within the eye. Results : Mass energy absorption and attenuation coefficients of the ocular media differ from those of water by as much as 12% within the 20–30 keV photon energy range. For all radionuclides studied, average doses to the tumor and lens regions in the full eye model differ from those for the plaque in water by 8%–10% and 13%–14%, respectively; the average doses to the tumor and lens regions differ between the full eye model and the TG-43 simulation by 2%–17% and 29%–34%, respectively. Replacing the surrounding tissues in the eye model with water increases the maximum and average doses to the lens by 2% and 3%, respectively. Substituting the tumor medium in the eye model for water, soft tissue, or an alternate melanoma composition affects tumor dose compared to the default eye model simulation by up to 16%. In the full eye model simulations, the average dose to the lens is larger by 7%–9% than the dose to the center of the lens, and the maximum dose to the optic nerve is 17%–22% higher than the dose to the optic disk for all radionuclides. In general, when normalized to the same prescription dose at the tumor apex, doses delivered to all structures of interest in the full eye model are lowest for{sup 103}Pd and highest for {sup 131}Cs, except for the tumor where the average dose is highest for {sup 103}Pd and lowest for {sup 131}Cs. Conclusions : The eye is not radiologically water-equivalent, as doses from simulations of the plaque in the full eye model differ considerably from doses for the plaque in a water phantom and from simulated TG-43 calculated doses. This demonstrates the importance of model-based dose calculations for eye plaque brachytherapy, for which accurate elemental compositions of ocular media are necessary.

  20. Model-based dose calculations for COMS eye plaque brachytherapy using an anatomically realistic eye phantom

    International Nuclear Information System (INIS)

    Purpose : To investigate the effects of the composition and geometry of ocular media and tissues surrounding the eye on dose distributions for COMS eye plaque brachytherapy with125I, 103Pd, or 131Cs seeds, and to investigate doses to ocular structures. Methods : An anatomically and compositionally realistic voxelized eye model with a medial tumor is developed based on a literature review. Mass energy absorption and attenuation coefficients for ocular media are calculated. Radiation transport and dose deposition are simulated using the EGSnrc Monte Carlo user-code BrachyDose for a fully loaded COMS eye plaque within a water phantom and our full eye model for the three radionuclides. A TG-43 simulation with the same seed configuration in a water phantom neglecting the plaque and interseed effects is also performed. The impact on dose distributions of varying tumor position, as well as tumor and surrounding tissue media is investigated. Each simulation and radionuclide is compared using isodose contours, dose volume histograms for the lens and tumor, maximum, minimum, and average doses to structures of interest, and doses to voxels of interest within the eye. Results : Mass energy absorption and attenuation coefficients of the ocular media differ from those of water by as much as 12% within the 20–30 keV photon energy range. For all radionuclides studied, average doses to the tumor and lens regions in the full eye model differ from those for the plaque in water by 8%–10% and 13%–14%, respectively; the average doses to the tumor and lens regions differ between the full eye model and the TG-43 simulation by 2%–17% and 29%–34%, respectively. Replacing the surrounding tissues in the eye model with water increases the maximum and average doses to the lens by 2% and 3%, respectively. Substituting the tumor medium in the eye model for water, soft tissue, or an alternate melanoma composition affects tumor dose compared to the default eye model simulation by up to 16%. In the full eye model simulations, the average dose to the lens is larger by 7%–9% than the dose to the center of the lens, and the maximum dose to the optic nerve is 17%–22% higher than the dose to the optic disk for all radionuclides. In general, when normalized to the same prescription dose at the tumor apex, doses delivered to all structures of interest in the full eye model are lowest for103Pd and highest for 131Cs, except for the tumor where the average dose is highest for 103Pd and lowest for 131Cs. Conclusions : The eye is not radiologically water-equivalent, as doses from simulations of the plaque in the full eye model differ considerably from doses for the plaque in a water phantom and from simulated TG-43 calculated doses. This demonstrates the importance of model-based dose calculations for eye plaque brachytherapy, for which accurate elemental compositions of ocular media are necessary

  1. Model-based dose calculations for COMS eye plaque brachytherapy using an anatomically realistic eye phantom

    Energy Technology Data Exchange (ETDEWEB)

    Lesperance, Marielle; Inglis-Whalen, M.; Thomson, R. M., E-mail: rthomson@physics.carleton.ca [Carleton Laboratory for Radiotherapy Physics, Department of Physics, Carleton University, Ottawa K1S 5B6 (Canada)

    2014-02-15

    Purpose : To investigate the effects of the composition and geometry of ocular media and tissues surrounding the eye on dose distributions for COMS eye plaque brachytherapy with{sup 125}I, {sup 103}Pd, or {sup 131}Cs seeds, and to investigate doses to ocular structures. Methods : An anatomically and compositionally realistic voxelized eye model with a medial tumor is developed based on a literature review. Mass energy absorption and attenuation coefficients for ocular media are calculated. Radiation transport and dose deposition are simulated using the EGSnrc Monte Carlo user-code BrachyDose for a fully loaded COMS eye plaque within a water phantom and our full eye model for the three radionuclides. A TG-43 simulation with the same seed configuration in a water phantom neglecting the plaque and interseed effects is also performed. The impact on dose distributions of varying tumor position, as well as tumor and surrounding tissue media is investigated. Each simulation and radionuclide is compared using isodose contours, dose volume histograms for the lens and tumor, maximum, minimum, and average doses to structures of interest, and doses to voxels of interest within the eye. Results : Mass energy absorption and attenuation coefficients of the ocular media differ from those of water by as much as 12% within the 20–30 keV photon energy range. For all radionuclides studied, average doses to the tumor and lens regions in the full eye model differ from those for the plaque in water by 8%–10% and 13%–14%, respectively; the average doses to the tumor and lens regions differ between the full eye model and the TG-43 simulation by 2%–17% and 29%–34%, respectively. Replacing the surrounding tissues in the eye model with water increases the maximum and average doses to the lens by 2% and 3%, respectively. Substituting the tumor medium in the eye model for water, soft tissue, or an alternate melanoma composition affects tumor dose compared to the default eye model simulation by up to 16%. In the full eye model simulations, the average dose to the lens is larger by 7%–9% than the dose to the center of the lens, and the maximum dose to the optic nerve is 17%–22% higher than the dose to the optic disk for all radionuclides. In general, when normalized to the same prescription dose at the tumor apex, doses delivered to all structures of interest in the full eye model are lowest for{sup 103}Pd and highest for {sup 131}Cs, except for the tumor where the average dose is highest for {sup 103}Pd and lowest for {sup 131}Cs. Conclusions : The eye is not radiologically water-equivalent, as doses from simulations of the plaque in the full eye model differ considerably from doses for the plaque in a water phantom and from simulated TG-43 calculated doses. This demonstrates the importance of model-based dose calculations for eye plaque brachytherapy, for which accurate elemental compositions of ocular media are necessary.

  2. Microstereolithography-Based Fabrication of Anatomically Shaped Beta-Tricalcium Phosphate Scaffolds for Bone Tissue Engineering

    Science.gov (United States)

    Du, Dajiang; Asaoka, Teruo; Shinohara, Makoto; Kageyama, Tomonori; Ushida, Takashi; Furukawa, Katsuko Sakai

    2015-01-01

    Porous ceramic scaffolds with shapes matching the bone defects may result in more efficient grafting and healing than the ones with simple geometries. Using computer-assisted microstereolithography (MSTL), we have developed a novel gelcasting indirect MSTL technology and successfully fabricated two scaffolds according to CT images of rabbit femur. Negative resin molds with outer 3D dimensions conforming to the femur and an internal structure consisting of stacked meshes with uniform interconnecting struts, 0.5?mm in diameter, were fabricated by MSTL. The second mold type was designed for cortical bone formation. A ceramic slurry of beta-tricalcium phosphate (?-TCP) with room temperature vulcanization (RTV) silicone as binder was cast into the molds. After the RTV silicone was completely cured, the composite was sintered at 1500°C for 5?h. Both gross anatomical shape and the interpenetrating internal network were preserved after sintering. Even cortical structure could be introduced into the customized scaffolds, which resulted in enhanced strength. Biocompatibility was confirmed by vital staining of rabbit bone marrow mesenchymal stromal cells cultured on the customized scaffolds for 5 days. This fabrication method could be useful for constructing bone substitutes specifically designed according to local anatomical defects. PMID:26504839

  3. Prognostic classification of Hodgkin disease in pathologic stage III, based on anatomic considerations

    Energy Technology Data Exchange (ETDEWEB)

    Desser, R.K.; Golomb, H.M.; Ultmann, J.E.; Ferguson, D.J.; Moran, E.M.; Griem, M.L.; Vardiman, J.; Miller, B.; Oetzel, N.; Sweet, D.

    1977-06-01

    Fifty-two patients with pathologic stage III Hodgkin's disease were studied in an effort to determine whether location of involved abdominal nodes influenced survival. Treatment consisted of total nodal radiotherapy with or without subsequent combination chemotherapy. The initial radiation field was the ''extended mantle,'' which included supradiaphragmatic nodes, the splenic hilar area, and paraaortic nodes to the level of L2-L4. Subsequently, lower paraaortic and iliac regions were treated (''lower inverted Y''). Patients with disease limited to the spleen and/or splenic, celiac, or portal nodes (''anatomic substage'' III/sub 1/) had a more favorable 5-yr survival than did patients with involvement of paraaortic, iliac, or mesenteric nodes (''anatomic substage'' III/sub 2/) : 93% versus 57%, respectively (p < 0.05). The addition of combination chemotherapy to total nodal irradiation was associated with improved survival of patients in stage III/sub 2/, but not of those in stage III/sub 1/.

  4. Cleft lip and palate: recommendations for dental anesthetic procedure based on anatomic evidences

    Scientific Electronic Library Online (English)

    Ivy Kiemle, Trindade-Suedam; Bruno Felipe, Gaia; Cheong Kuo, Cheng; Paulo Alceu Kiemle, Trindade; José Carlos da Cunha, Bastos; Beatriz Silva Câmara, Mattos.

    2012-02-01

    Full Text Available Patients with cleft lip and palate usually present dental anomalies of number, shape, structure and position in the cleft area and the general dentist is frequently asked to restore or extract those teeth. Considering that several anatomic variations are expected in teeth adjacent to cleft areas and [...] that knowledge of these variations by general dentists is required for optimal treatment, the objectives of this paper are: 1) to describe changes in the innervation pattern of anterior teeth and soft tissue caused by the presence of a cleft, 2) to describe a local anesthetic procedure in unilateral and bilateral clefts, and 3) to provide recommendations to improve anesthetic procedures in patients with cleft lip and palate. The cases of 2 patients are presented: one with complete unilateral cleft lip and palate, and the other with complete bilateral cleft lip and palate. The patients underwent local anesthesia in the cleft area in order to extract teeth with poor bone support. The modified anesthetic procedure, respecting the altered course of nerves in the cleft maxilla and soft tissue alterations at the cleft site, was accomplished successfully and the tooth extraction was performed with no pain to the patients. General dentists should be aware of the anatomic variations in nerve courses in the cleft area to offer high quality treatment to patients with cleft lip and palate.

  5. Retrosplenial cortex codes for permanent landmarks.

    OpenAIRE

    Auger, S. D.; Mullally, S. L.; Maguire, E. A.

    2012-01-01

    Landmarks are critical components of our internal representation of the environment, yet their specific properties are rarely studied, and little is known about how they are processed in the brain. Here we characterised a large set of landmarks along a range of features that included size, visual salience, navigational utility, and permanence. When human participants viewed images of these single landmarks during functional magnetic resonance imaging (fMRI), parahippocampal cortex (PHC) and r...

  6. Neurocognitive development of memory for landmarks

    OpenAIRE

    van Ekert, Janneke; Wegman, Joost; Janzen, Gabriele

    2015-01-01

    The capacity to detect landmarks in the environment and to associate each landmark with its spatial context is a fundamental operation for navigation, especially when the context is relevant for successful navigation. Recent evidence suggests robust age-related improvements in contextual memory. The current study investigated the effect of spatial context on landmark recognition memory in children and adolescents. Participants, ages 8–18, watched a video depicting a route through a virtual en...

  7. Desert Ants Learn Vibration and Magnetic Landmarks

    OpenAIRE

    Buehlmann, Cornelia; Hansson, Bill S.; Knaden, Markus

    2012-01-01

    The desert ants Cataglyphis navigate not only by path integration but also by using visual and olfactory landmarks to pinpoint the nest entrance. Here we show that Cataglyphis noda can additionally use magnetic and vibrational landmarks as nest-defining cues. The magnetic field may typically provide directional rather than positional information, and vibrational signals so far have been shown to be involved in social behavior. Thus it remains questionable if magnetic and vibration landmarks a...

  8. Detection, visualization and animation of abnormal anatomic structure with a deformable probabilistic brain atlas based on random vector field transformations.

    Science.gov (United States)

    Thompson, P M; Toga, A W

    1997-09-01

    This paper describes the design, implementation and preliminary results of a technique for creating a comprehensive probabilistic atlas of the human brain based on high-dimensional vector field transformations. The goal of the atlas is to detect and quantify distributed patterns of deviation from normal anatomy, in a 3-D brain image from any given subject. The algorithm analyzes a reference population of normal scans and automatically generates color-coded probability maps of the anatomy of new subjects. Given a 3-D brain image of a new subject, the algorithm calculates a set of high-dimensional volumetric maps (with typically 384(2) x 256 x 3 approximately 10(8) degrees of freedom) elastically deforming this scan into structural correspondence with other scans, selected one by one from an anatomic image database. The family of volumetric warps thus constructed encodes statistical properties and directional biases of local anatomical variation throughout the architecture of the brain. A probability space of random transformations, based on the theory of anisotropic Gaussian random fields, is then developed to reflect the observed variability in stereotaxic space of the points whose correspondences are found by the warping algorithm. A complete system of 384(2) x 256 probability density functions is computed, yielding confidence limits in stereotaxic space for the location of every point represented in the 3-D image lattice of the new subject's brain. Color-coded probability maps are generated, densely defined throughout the anatomy of the new subject. These indicate locally the probability of each anatomic point being unusually situated, given the distributions of corresponding points in the scans of normal subjects. 3-D MRI and high-resolution cryosection volumes are analyzed from subjects with metastatic tumors and Alzheimer's disease. Gradual variations and continuous deformations of the underlying anatomy are simulated and their dynamic effects on regional probability maps are animated in video format (on the accompanying CD-ROM). Applications of the deformable probabilistic atlas include the transfer of multi-subject 3-D functional, vascular and histologic maps onto a single anatomic template, the mapping of 3-D atlases onto the scans of new subjects, and the rapid detection, quantification and mapping of local shape changes in 3-D medical images in disease and during normal or abnormal growth and development. PMID:9873911

  9. Radiobiological model-based bio-anatomical quality assurance in intensity-modulated radiation therapy for prostate cancer

    International Nuclear Information System (INIS)

    A bio-anatomical quality assurance (QA) method employing tumor control probability (TCP) and normal tissue complication probability (NTCP) is described that can integrate radiobiological effects into intensity-modulated radiation therapy (IMRT). We evaluated the variations in the radiobiological effects caused by random errors (r-errors) and systematic errors (s-errors) by evaluating TCP and NTCP in two groups: patients with an intact prostate (Gintact) and those who have undergone prostatectomy (Gtectomy). The r-errors were generated using an isocenter shift of ±1 mm to simulate a misaligned patient set-up. The s-errors were generated using individual leaves that were displaced inwardly and outwardly by 1 mm on multileaf collimator field files. Subvolume-based TCP and NTCP were visualized on computed tomography (CT) images to determine the radiobiological effects on the principal structures. The bio-anatomical QA using the TCP and NTCP maps differentiated the critical radiobiological effects on specific volumes, particularly at the anterior rectal walls and planning target volumes. The s-errors showed a TCP variation of -40-25% in Gtectomy and -30-10% in Gintact, while the r-errors were less than 1.5% in both groups. The r-errors for the rectum and bladder showed higher NTCP variations at ±20% and ±10%, respectively, and the s-errors were greater than ±65% for both. This bio-anatomical method, as a patient-specific IMRT QA, can provide distinct indications of clinically significant radiobiological effects beyond the minimization of probable physical dose errors in phantoms. (author)

  10. The Virtual Family-development of surface-based anatomical models of two adults and two children for dosimetric simulations

    International Nuclear Information System (INIS)

    The objective of this study was to develop anatomically correct whole body human models of an adult male (34 years old), an adult female (26 years old) and two children (an 11-year-old girl and a six-year-old boy) for the optimized evaluation of electromagnetic exposure. These four models are referred to as the Virtual Family. They are based on high resolution magnetic resonance (MR) images of healthy volunteers. More than 80 different tissue types were distinguished during the segmentation. To improve the accuracy and the effectiveness of the segmentation, a novel semi-automated tool was used to analyze and segment the data. All tissues and organs were reconstructed as three-dimensional (3D) unstructured triangulated surface objects, yielding high precision images of individual features of the body. This greatly enhances the meshing flexibility and the accuracy with respect to thin tissue layers and small organs in comparison with the traditional voxel-based representation of anatomical models. Conformal computational techniques were also applied. The techniques and tools developed in this study can be used to more effectively develop future models and further improve the accuracy of the models for various applications. For research purposes, the four models are provided for free to the scientific community. (note)

  11. Conservative management of large avulsions of the lip and local landmarks.

    Science.gov (United States)

    Rhee, Samuel T; Colville, Christopher; Buchman, Steven R

    2004-01-01

    Large lip avulsion injuries that involve significant tissue loss to the lip vermilion and other local landmarks can often pose a surgical dilemma for the reconstructive surgeon. Immediate reconstruction of these injuries are frequently performed using local flaps and adjacent tissue transfer to close the defect, but these repairs frequently suffer from the unfortunate consequence of increased associated scarring and further permanent distortion of the local anatomy. We present 2 patients sustaining dog bite injuries associated with extensive traumatic tissue loss to the lip vermilion and other local landmarks. These patients were treated conservatively with excellent functional and cosmetic results. A single minor surgical revision of 1 patient's cupid's bow was performed 1 year after injury. In cases of significant traumatic avulsion involving the lip vermilion and the perioral composite soft tissue, even with injuries including delicate anatomic landmarks, healing by secondary intention can be instituted as the initial treatment of choice in younger patients, often providing optimal results. PMID:14716166

  12. Anatomical Bases of the Mechanical Complications during the Positioning of Subclavian Catheters

    Directory of Open Access Journals (Sweden)

    Giannelli, Alberto

    2011-12-01

    Full Text Available The subclavian vein is located at the edge of scalenecosto-clavicular triangle, surrounded by the medial aspect of the clavicle in its anterior side, the first rib on its underside and the anterior scalene muscle in his back side. Subclavian catheterization by puncture is not a harmless procedure, in fact, is the path that shows more of major mechanical complications. The main mechanical complications observed with the subclavian approach are the development of uncomplicated supraclavicular hematoma (5% and pneumothorax (1.5 - 3%. The fact of not having in mind the concept of proximity of the subclavian vein with the subclavian artery and the lung, favors the occurrence of such complications. The aim of this work is to show the structures involved in more frequent mechanical complications of percutaneous subclavian venous catheters.We used human cadaveric material, preserved in formaldehyde 10%, in which conventional and special dissected supra-and infraclavicular regions showing subclavian vein and adjacent structures.Through dissection of supraclavicular and infraclavicular regions was achieved by a proper display of the morphology of the subclavian vein and surrounding structures to be taken into account while performing the puncture of the vein and the development of complications.Considering that the puncture of the subclavian vein is a blind procedure where the vein can not be seen through the skin or palpated, it is essential to accurate knowledge of the anatomical relations of the region to successfully channel the vein and lower the risk of mechanical complications.

  13. LARGE AREA LANDMARKS - DYNAMAP V.12.2

    Science.gov (United States)

    GDT Large Area Landmarks represents common landmark areas within United States including military areas, prisons, educational institutions, amusement centers, government centers, sport centers, golf courses, and cemeteries.

  14. Landmark Finding Algorithms for Indoor Autonomous Mobile Robot Localization

    Directory of Open Access Journals (Sweden)

    L. To?th

    2015-12-01

    Full Text Available This contribution is oriented to ways of computer vision algorithms for mobile robot localization in internal and external agricultural environment. The main aim of this work was to design, create, verify and evaluate speed and functionality of computer vision localization algorithm. An input colour camera data and depth data were captured by MS® Kinect sensor that was mounted on 6-wheel-drive mobile robot chassis. The design of the localization algorithm was focused to the most significant blobs and points (landmarks on the colour picture. Actual coordinates of autonomous mobile robot were calculated out from measured distances (depth sensor and calculated angles (RGB camera with respect to landmark points. Time measurement script was used to compare the speed of landmark finding algorithm for localization in case of one and more landmarks on picture. The main source code was written in MS Visual studio C# programming language with Microsoft.Kinect.1.7.dll on Windows based PC. Algorithms described in this article were created for a future development of an autonomous agronomical m obile robot localization and control.

  15. Landmark analysis of clear and conversational speaking styles

    Science.gov (United States)

    Boyce, Suzanne; Bradlow, Ann; MacAuslan, Joel

    2005-09-01

    Speakers appear to adjust speech production according to tradeoffs between intelligibility and economy of effort [Lindblom (1992)]. Recently, there has been much interest in investigation of differences between the clear style of speech addressed to disadvantaged listeners (non-native speakers, hearing impaired listeners, etc.) and ordinary, or conversational speaking style. Clear speech has been shown to be more intelligible across a wide range of listener types [Bradlow et al., (2002); Bradlow et al., (2003)], but the full range of parameters of variation remain undetermined. Recently also, the use of abrupt changes in the speech signal, i.e., acoustic landmarks, as an organizing principle for speech recognition has garnered attention [Espy-Wilson (2005)]. Using a landmark analysis procedure based on that of Stevens (1991) and Liu (1995), we present evidence that clear and conversational speaking styles can be distinguished in terms of the distribution of particular clusters of landmarks, corresponding very roughly to syllable-sized units. The implications of this differential distribution of landmarks across speaking styles for the organization of speech production will be discussed.

  16. Population-based evaluation of a suggested anatomic and clinical classification of congenital heart defects based on the International Paediatric and Congenital Cardiac Code

    Directory of Open Access Journals (Sweden)

    Goffinet François

    2011-10-01

    Full Text Available Abstract Background Classification of the overall spectrum of congenital heart defects (CHD has always been challenging, in part because of the diversity of the cardiac phenotypes, but also because of the oft-complex associations. The purpose of our study was to establish a comprehensive and easy-to-use classification of CHD for clinical and epidemiological studies based on the long list of the International Paediatric and Congenital Cardiac Code (IPCCC. Methods We coded each individual malformation using six-digit codes from the long list of IPCCC. We then regrouped all lesions into 10 categories and 23 subcategories according to a multi-dimensional approach encompassing anatomic, diagnostic and therapeutic criteria. This anatomic and clinical classification of congenital heart disease (ACC-CHD was then applied to data acquired from a population-based cohort of patients with CHD in France, made up of 2867 cases (82% live births, 1.8% stillbirths and 16.2% pregnancy terminations. Results The majority of cases (79.5% could be identified with a single IPCCC code. The category "Heterotaxy, including isomerism and mirror-imagery" was the only one that typically required more than one code for identification of cases. The two largest categories were "ventricular septal defects" (52% and "anomalies of the outflow tracts and arterial valves" (20% of cases. Conclusion Our proposed classification is not new, but rather a regrouping of the known spectrum of CHD into a manageable number of categories based on anatomic and clinical criteria. The classification is designed to use the code numbers of the long list of IPCCC but can accommodate ICD-10 codes. Its exhaustiveness, simplicity, and anatomic basis make it useful for clinical and epidemiologic studies, including those aimed at assessment of risk factors and outcomes.

  17. Individual 3D region-of-interest atlas of the human brain: knowledge-based class image analysis for extraction of anatomical objects

    Science.gov (United States)

    Wagenknecht, Gudrun; Kaiser, Hans-Juergen; Sabri, Osama; Buell, Udalrich

    2000-06-01

    After neural network-based classification of tissue types, the second step of atlas extraction is knowledge-based class image analysis to get anatomically meaningful objects. Basic algorithms are region growing, mathematical morphology operations, and template matching. A special algorithm was designed for each object. The class label of each voxel and the knowledge about the relative position of anatomical objects to each other and to the sagittal midplane of the brain can be utilized for object extraction. User interaction is only necessary to define starting, mid- and end planes for most object extractions and to determine the number of iterations for erosion and dilation operations. Extraction can be done for the following anatomical brain regions: cerebrum; cerebral hemispheres; cerebellum; brain stem; white matter (e.g., centrum semiovale); gray matter [cortex, frontal, parietal, occipital, temporal lobes, cingulum, insula, basal ganglia (nuclei caudati, putamen, thalami)]. For atlas- based quantification of functional data, anatomical objects can be convoluted with the point spread function of functional data to take into account the different resolutions of morphological and functional modalities. This method allows individual atlas extraction from MRI image data of a patient without the need of warping individual data to an anatomical or statistical MRI brain atlas.

  18. A framework for evaluation of deformable image registration spatial accuracy using large landmark point sets

    International Nuclear Information System (INIS)

    Expert landmark correspondences are widely reported for evaluating deformable image registration (DIR) spatial accuracy. In this report, we present a framework for objective evaluation of DIR spatial accuracy using large sets of expert-determined landmark point pairs. Large samples (>1100) of pulmonary landmark point pairs were manually generated for five cases. Estimates of inter- and intra-observer variation were determined from repeated registration. Comparative evaluation of DIR spatial accuracy was performed for two algorithms, a gradient-based optical flow algorithm and a landmark-based moving least-squares algorithm. The uncertainty of spatial error estimates was found to be inversely proportional to the square root of the number of landmark point pairs and directly proportional to the standard deviation of the spatial errors. Using the statistical properties of this data, we performed sample size calculations to estimate the average spatial accuracy of each algorithm with 95% confidence intervals within a 0.5 mm range. For the optical flow and moving least-squares algorithms, the required sample sizes were 1050 and 36, respectively. Comparative evaluation based on fewer than the required validation landmarks results in misrepresentation of the relative spatial accuracy. This study demonstrates that landmark pairs can be used to assess DIR spatial accuracy within a narrow uncertainty range.

  19. 23 CFR 750.710 - Landmark signs.

    Science.gov (United States)

    2010-04-01

    ...RIGHT-OF-WAY AND ENVIRONMENT HIGHWAY BEAUTIFICATION Outdoor Advertising Control § 750.710 Landmark signs. (a) 23...is permitted. Substantial change in size, lighting, or message content will terminate its exempt...

  20. Cortical projection of the inferior choroidal point as a reliable landmark to place the corticectomy and reach the temporal horn through a middle temporal gyrus approach

    Directory of Open Access Journals (Sweden)

    Thomas Frigeri

    2014-10-01

    Full Text Available Objective To establish preoperatively the localization of the cortical projection of the inferior choroidal point (ICP and use it as a reliable landmark when approaching the temporal horn through a middle temporal gyrus access. To review relevant anatomical features regarding selective amigdalohippocampectomy (AH for treatment of mesial temporal lobe epilepsy (MTLE. Method The cortical projection of the inferior choroidal point was used in more than 300 surgeries by one authors as a reliable landmark to reach the temporal horn. In the laboratory, forty cerebral hemispheres were examined. Conclusion The cortical projection of the ICP is a reliable landmark for reaching the temporal horn.

  1. Landmark perception planning for mobile robot localization

    OpenAIRE

    Armingol, José M.; Moreno, Luis; Escalera, Arturo de la; Salichs, Miguel A.

    1998-01-01

    This paper presents a fuzzy perception planner that takes into account the time cost, the suitability of every landmark detection and the different uncertainties the robot encounters along its path for mobile robot localization. The sensor used is a camera with a motorized zoom on a pan & tilt platform and the artificial landmarks are circles detected through normalized grayscale correlation. An Extended Kalman Filter is used to correct the position and orientation of the vehicle. The resulti...

  2. 36 CFR 62.8 - Natural landmark designation removal.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Natural landmark designation... INTERIOR NATIONAL NATURAL LANDMARKS PROGRAM § 62.8 Natural landmark designation removal. (a) Criteria for removal. (1) Except as provided in paragraph (f) of this section, national natural landmark designation...

  3. 36 CFR 65.6 - Recognition of National Historic Landmarks.

    Science.gov (United States)

    2010-07-01

    ... Historic Landmarks. 65.6 Section 65.6 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL HISTORIC LANDMARKS PROGRAM § 65.6 Recognition of National Historic Landmarks. (a) Following designation of a property by the Secretary as a National Historic Landmark, the...

  4. 36 CFR 65.4 - National Historic Landmark criteria.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false National Historic Landmark... INTERIOR NATIONAL HISTORIC LANDMARKS PROGRAM § 65.4 National Historic Landmark criteria. The criteria applied to evaluate properties for possible designation as National Historic Landmarks or...

  5. 36 CFR 65.7 - Monitoring National Historic Landmarks.

    Science.gov (United States)

    2010-07-01

    ... Landmarks. 65.7 Section 65.7 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL HISTORIC LANDMARKS PROGRAM § 65.7 Monitoring National Historic Landmarks. (a) NPS maintains a continuing relationship with the owners of National Historic Landmarks. Periodic...

  6. Ischial and pubic osteotomies performed by medial approach during periacetabular osteotomies: an anatomical study

    OpenAIRE

    Bilgili, Fuat; Gurses, Ilke Ali; Ozkaya, Ufuk; Gayretli, Ozcan; Parmaksizoglu, Atilla Sancar; Kale, Aysin Cetiner

    2013-01-01

    Objective: The aim of this study was to identify the anatomic landmarks of ischial and pubic osteotomies performed as part of Bernese periacetabular osteotomy, measure the distances of these landmarks to the main neurovascular structures and determine whether these osteotomies can be performed and visualized using a medial approach. Methods: The study included 20 hemipelvises of 10 formaldehyde-fixed cadavers. A medial surgical approach between the adductor longus and pectineus muscles was...

  7. High-risk human papillomavirus infection involving multiple anatomic sites of the female lower genital tract: a multiplex real-time polymerase chain reaction-based study.

    Science.gov (United States)

    Hui, Yiang; Manna, Pradip; Ou, Joyce J; Kerley, Spencer; Zhang, Cunxian; Sung, C James; Lawrence, W Dwayne; Quddus, M Ruhul

    2015-09-01

    High-risk human papillomavirus infection usually is seen at one anatomic site in an individual. Rarely, infection at multiple anatomic sites of the female lower genital tract in the same individual is encountered either simultaneously and/or at a later date. The current study identifies the various subtypes of high-risk human papillomavirus infection in these scenarios and analyzes the potential significance of these findings. High-risk human papillomavirus infection involving 22 anatomic sites from 7 individuals was identified after institutional review board approval. Residual paraffin-embedded tissue samples were retrieved, and all 15 high-risk human papillomavirus were identified and viral load quantified using multiplex real-time polymerase chain reaction-based method. Multiple high-risk human papillomavirus subtypes were identified in 32% of the samples and as many as 5 different subtypes of high-risk human papillomavirus infection in a single anatomic site. In general, each anatomic site has unique combination of viral subtypes, although one individual showed overlapping subtypes in the vagina, cervix, and vulvar samples. Higher viral load and rare subtypes are more frequent in younger patients and in dysplasia compared with carcinoma. Follow-up ranging from 3 to 84 months revealed persistent high-risk human papillomavirus infection in 60% of cases. PMID:26220161

  8. Support vector machine-based classification of Alzheimer's disease from whole-brain anatomical MRI

    Energy Technology Data Exchange (ETDEWEB)

    Magnin, Benoit [UMR-S 678, Inserm, Paris (France)]|[UMR-S 610, Inserm, Paris (France)]|[UMPC Univ Paris 06, Faculte de Medecine Pitie-Salpetriere, Paris (France)]|[IFR 49, Gif-sur-Yvette (France); Mesrob, Lilia [UMR-S 610, Inserm, Paris (France)]|[UMPC Univ Paris 06, Faculte de Medecine Pitie-Salpetriere, Paris (France)]|[IFR 49, Gif-sur-Yvette (France); Kinkingnehun, Serge [UMR-S 610, Inserm, Paris (France)]|[UMPC Univ Paris 06, Faculte de Medecine Pitie-Salpetriere, Paris (France)]|[IFR 49, Gif-sur-Yvette (France)]|[BRAIN, Vitry-sur-Seine (France); Pelegrini-Issac, Melanie [UMR-S 678, Inserm, Paris (France)]|[UMPC Univ Paris 06, Faculte de Medecine Pitie-Salpetriere, Paris (France)]|[IFR 49, Gif-sur-Yvette (France); Colliot, Olivier [IFR 49, Gif-sur-Yvette (France)]|[UPR 640 LENA, CNRS, Paris (France); Sarazin, Marie; Dubois, Bruno [UMR-S 610, Inserm, Paris (France)]|[UMPC Univ Paris 06, Faculte de Medecine Pitie-Salpetriere, Paris (France)]|[IFR 49, Gif-sur-Yvette (France)]|[Pitie-Salpetriere Hospital, Department of Neurology, Paris (France); Lehericy, Stephane [UMR-S 610, Inserm, Paris (France)]|[UMPC Univ Paris 06, Faculte de Medecine Pitie-Salpetriere, Paris (France)]|[IFR 49, Gif-sur-Yvette (France)]|[UMPC Univ. Paris 06, Center for NeuroImaging Research-CENIR, Paris (France)]|[Pitie-Salpetriere Hospital, Department of Neuroradiology, Paris (France); Benali, Habib [UMR-S 678, Inserm, Paris (France)]|[UMPC Univ Paris 06, Faculte de Medecine Pitie-Salpetriere, Paris (France)]|[IFR 49, Gif-sur-Yvette (France)]|[UNF/CRIUGM, Universite de Montreal, Montreal, QC (Canada)

    2009-02-15

    We present and evaluate a new automated method based on support vector machine (SVM) classification of whole-brain anatomical magnetic resonance imaging to discriminate between patients with Alzheimer's disease (AD) and elderly control subjects. We studied 16 patients with AD [mean age {+-} standard deviation (SD)=74.1 {+-}5.2 years, mini-mental score examination (MMSE) = 23.1 {+-} 2.9] and 22 elderly controls (72.3{+-}5.0 years, MMSE=28.5{+-} 1.3). Three-dimensional T1-weighted MR images of each subject were automatically parcellated into regions of interest (ROIs). Based upon the characteristics of gray matter extracted from each ROI, we used an SVM algorithm to classify the subjects and statistical procedures based on bootstrap resampling to ensure the robustness of the results. We obtained 94.5% mean correct classification for AD and control subjects (mean specificity, 96.6%; mean sensitivity, 91.5%). Our method has the potential in distinguishing patients with AD from elderly controls and therefore may help in the early diagnosis of AD. (orig.)

  9. Online updating of context-aware landmark detectors for prostate localization in daily treatment CT images

    International Nuclear Information System (INIS)

    Purpose: In image guided radiation therapy, it is crucial to fast and accurately localize the prostate in the daily treatment images. To this end, the authors propose an online update scheme for landmark-guided prostate segmentation, which can fully exploit valuable patient-specific information contained in the previous treatment images and can achieve improved performance in landmark detection and prostate segmentation. Methods: To localize the prostate in the daily treatment images, the authors first automatically detect six anatomical landmarks on the prostate boundary by adopting a context-aware landmark detection method. Specifically, in this method, a two-layer regression forest is trained as a detector for each target landmark. Once all the newly detected landmarks from new treatment images are reviewed or adjusted (if necessary) by clinicians, they are further included into the training pool as new patient-specific information to update all the two-layer regression forests for the next treatment day. As more and more treatment images of the current patient are acquired, the two-layer regression forests can be continually updated by incorporating the patient-specific information into the training procedure. After all target landmarks are detected, a multiatlas random sample consensus (multiatlas RANSAC) method is used to segment the entire prostate by fusing multiple previously segmented prostates of the current patient after they are aligned to the current treatment image. Subsequently, the segmented prostate of the current treatment image is again reviewed (or even adjusted if needed) by clinicians before including it as a new shape example into the prostate shape dataset for helping localize the entire prostate in the next treatment image. Results: The experimental results on 330 images of 24 patients show the effectiveness of the authors’ proposed online update scheme in improving the accuracies of both landmark detection and prostate segmentation. Besides, compared to the other state-of-the-art prostate segmentation methods, the authors’ method achieves the best performance. Conclusions: By appropriate use of valuable patient-specific information contained in the previous treatment images, the authors’ proposed online update scheme can obtain satisfactory results for both landmark detection and prostate segmentation

  10. Online updating of context-aware landmark detectors for prostate localization in daily treatment CT images

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Xiubin [College of Geographic and Biologic Information, Nanjing University of Posts and Telecommunications, Nanjing, Jiangsu 210015, China and IDEA Lab, Department of Radiology and BRIC, University of North Carolina at Chapel Hill, 130 Mason Farm Road, Chapel Hill, North Carolina 27510 (United States); Gao, Yaozong [IDEA Lab, Department of Radiology and BRIC, University of North Carolina at Chapel Hill, 130 Mason Farm Road, Chapel Hill, North Carolina 27510 (United States); Shen, Dinggang, E-mail: dgshen@med.unc.edu [IDEA Lab, Department of Radiology and BRIC, University of North Carolina at Chapel Hill, 130 Mason Farm Road, Chapel Hill, North Carolina 27510 and Department of Brain and Cognitive Engineering, Korea University, Seoul (Korea, Republic of)

    2015-05-15

    Purpose: In image guided radiation therapy, it is crucial to fast and accurately localize the prostate in the daily treatment images. To this end, the authors propose an online update scheme for landmark-guided prostate segmentation, which can fully exploit valuable patient-specific information contained in the previous treatment images and can achieve improved performance in landmark detection and prostate segmentation. Methods: To localize the prostate in the daily treatment images, the authors first automatically detect six anatomical landmarks on the prostate boundary by adopting a context-aware landmark detection method. Specifically, in this method, a two-layer regression forest is trained as a detector for each target landmark. Once all the newly detected landmarks from new treatment images are reviewed or adjusted (if necessary) by clinicians, they are further included into the training pool as new patient-specific information to update all the two-layer regression forests for the next treatment day. As more and more treatment images of the current patient are acquired, the two-layer regression forests can be continually updated by incorporating the patient-specific information into the training procedure. After all target landmarks are detected, a multiatlas random sample consensus (multiatlas RANSAC) method is used to segment the entire prostate by fusing multiple previously segmented prostates of the current patient after they are aligned to the current treatment image. Subsequently, the segmented prostate of the current treatment image is again reviewed (or even adjusted if needed) by clinicians before including it as a new shape example into the prostate shape dataset for helping localize the entire prostate in the next treatment image. Results: The experimental results on 330 images of 24 patients show the effectiveness of the authors’ proposed online update scheme in improving the accuracies of both landmark detection and prostate segmentation. Besides, compared to the other state-of-the-art prostate segmentation methods, the authors’ method achieves the best performance. Conclusions: By appropriate use of valuable patient-specific information contained in the previous treatment images, the authors’ proposed online update scheme can obtain satisfactory results for both landmark detection and prostate segmentation.

  11. Predicting efficiency of post-induction mask ventilation based on demographic and anatomical factors

    Directory of Open Access Journals (Sweden)

    Mahmoud Saghaei

    2012-01-01

    Conclusions: Using EMV is an easy and reliable tool for measuring efficiency of mask ventilation. Based on the result of this study, EMV can be estimated from patient?s demographic and physical factors. In edentolous patients, using the lip-over-mask method results in adequate ventilation of lungs.

  12. Improved Detection of Landmarks on 3D Human Face Data

    OpenAIRE

    Shu LIANG; Wu, Jia; Weinberg, Seth M; Shapiro, Linda G

    2013-01-01

    Craniofacial researchers make heavy use of established facial landmarks in their morphometric analyses. For studies on very large facial image datasets, the standard approach of manual landmarking is very labor intensive. With the goal of producing 20 established landmarks, we have developed a geometric methodology that can automatically locate 10 established landmark points and 7 other supporting points on human 3D facial scans. Then, to improve accuracy and produce all 20 landmarks, a defor...

  13. Associative basis of landmark learning and integration in vertebrates

    OpenAIRE

    Kenneth J. Leising; Aaron P. Blaisdell

    2009-01-01

    Early work on spatial navigation evaluated what stimuli (kinesthetic or extra-maze) support small-scale navigation and the nature of the underlying learning (place versus response) process. Contemporary research has focused primarily on how cues interact to determine spatial search. This review covers three general findings from research on landmark-based spatial search in vertebrates. First, pigeons and rats encode simple spatial maps in both open-field and touchscreen environments. Second, ...

  14. Elections and landmark policies in Tanzania and Uganda

    DEFF Research Database (Denmark)

    Kjær, Anne Mette; Therkildsen, Ole

    2013-01-01

    Much of the relevant literature on Africa downplays the salience of elections for policy-making and implementation. Instead, the importance of factors such as clientelism, ethnicity, organized interest group and donor influence, is emphasized. We argue that, in addition, elections now motivate political elites to focus on policies they perceive to be able to gain votes. This is based on analyses of six landmark decisions made during the last fifteen years in the social, productive and public fin...

  15. Detection of point landmarks in multidimensional tensor data☆

    Science.gov (United States)

    Ruiz-Alzola, J.; Kikinis, R.; Westin, C.-F.

    2015-01-01

    This paper describes a unified approach to the detection of point landmarks—whose neighborhoods convey discriminant information—including multidimensional scalar, vector, and higher-order tensor data. The method is based on the interpretation of generalized correlation matrices derived from the gradient of tensor functions, a probabilistic interpretation of point landmarks, and the application of tensor algebra. Results on both synthetic and real tensor data are presented. PMID:26005233

  16. Color-contrast landmark detection and encoding in outdoor images

    OpenAIRE

    Todt, Eduardo; Torras Genís, Carme

    2005-01-01

    This paper describes a system to extract salient regions from an outdoor image and match them against a database of previously acquired landmarks. Region saliency is based mainly on color contrast, although intensity and texture orientation are also taken into account. Remarkably, color constancy is embedded in the saliency detection process through a novel color ratio algorithm that makes the system robust to illumination changes, so common in outdoor environments. A region is characterized ...

  17. The distally based radial forearm fasciosubcutaneous flap with preservation of the radial artery: an anatomic and clinical approach.

    Science.gov (United States)

    Weinzweig, N; Chen, L; Chen, Z W

    1994-10-01

    The axial-pattern reverse radial forearm fasciocutaneous flap has become one of the primary flaps for reconstruction of soft-tissue defects of the hand. The two main disadvantages of this flap are (1) sacrifice of a major artery that may possibly jeopardize hand viability and (2) morbidity and appearance of the donor site. In an effort to overcome these drawbacks, an anatomic study of a distally based radial forearm fasciosubcutaneous flap with preservation of the radial artery was conducted. Seventeen fresh cadaver forearms were dissected to investigate the contribution of the distal radial artery and its superficial and deep branches to the fasciosubcutaneous plexus of the forearm. The blood supply to the radial forearm fasciosubcutaneous tissue was found to emanate from 6 to 10 septocutaneous perforators of the distal radial artery in the vicinity of the anatomic snuff box that "fan out" at the level of the deep fascia to form a rich plexus supplying the forearm fascia, subcutaneous tissue, and skin. There appeared to be a definite directional component, with the arterioles running longitudinally along the intermuscular septum. The deep fascia and subcutaneous tissue were found to have their own venous system accompanying the small perforating arterioles. Encouraged by these findings, we proceeded to utilize this fasciosubcutaneous flap for coverage of the thumb-index web space (three patients), the dorsum of the hand (two patients), and both the palmar and dorsal aspects of the hand (one patient). Five flaps had almost complete survival. The largest flap in our series suffered significant loss. Minor skin-graft loss occurred in a few cases, and we now delay skin grafting for several days. The distally based radial forearm fasciosubcutaneous flap with preservation of the radial artery can be a very useful and reliable alternative for repairing soft-tissue defects of the hand, obviating the need for the classic fasciocutaneous flap or even a free flap. This flap not only preserves the radial artery, which is essential in cases where only the radial artery is functioning, such as following severe hand injuries, but also provides a more acceptable donor site. PMID:7938291

  18. Patient specific color texture mapping of CT-based anatomical surface models utilizing cryosection data.

    Science.gov (United States)

    Knapp, D; Kerr, J P; Sellberg, M

    1997-01-01

    In traditional medical imaging modalities, color and texture information can add considerable information for diagnostics. Presently, multimodal images of a patient are unregistered and referenced independent of each other, or registered and fused into a single hybrid volume. Doctors and other medical professionals need to be able to visualize and interrogate, on a per-patient basis, a wide variety of 2D and 3D data representations that can be created from non-invasive imaging modalities, such as MRI and CT. In addition, any colorization that may be applied to the image data is strictly based on tissue density, radiation emission, or magnetic signature, and not on any physiological foundation. In order for "true-to-life" color information to be incorporated with non-invasive imaging techniques, and for it to be of consistent quality across the entire body, a single whole-body cryosection specimen with associated medical image data is needed. The National Library of Medicine's Visible Human Project offers just such a specimen. Using the full-body medical image data along with the cryosection images of the Visible Human subject, a set of color lookup tables for all visually well defined structures and organs can be created. As a result, patient-specific colorization based on real tissue color and characteristics can be incorporated into traditional intensity-based imaging modalities. The primary goal of this work has been to create CT color lookup tables for all visually well-defined structures in the Visible Human male cryosection data set. The subsequent goal has been to develop a method for stripping textures from a volumetric data set for polygonal models and non-uniform rational B-spline (NURBS) models, also generated from the volumetric data. PMID:10168955

  19. Automated localization of pelvic anatomical coordinate system from 3D CT data of the hip using statistical atlas

    International Nuclear Information System (INIS)

    Localization of the pelvic anatomical coordinate system is a prerequisite for patient-specific preoperative planning and joint motion simulation for hip surgery. Our aim is to automate localization of the pelvic anatomical coordinate system from 3D CT data. In this paper, we propose a statistical atlas-based method that consists of three steps. The first step is spatial normalization using a probabilistic atlas. The second step is feature point recognition using a statistical landmark model. The final step is coordinate system refinement using a standard CT atlas. We applied the proposed method to 39 datasets. Compared to manual localization by an experienced surgeon, the average positional error was 2.37±1.30 mm and the average orientation error was 1.07±0.50 degrees. These results demonstrate the usefulness of the proposed method. (author)

  20. Dosimetric intercomparison for multicenter clinical trials using a patient-based anatomic pelvic phantom

    Energy Technology Data Exchange (ETDEWEB)

    Ebert, M. A.; Harrison, K. M.; Howlett, S. J.; Cornes, D.; Bulsara, M.; Hamilton, C. S.; Kron, T.; Joseph, D. J.; Denham, J. W. [Department of Radiation Oncology, Sir Charles Gairdner Hospital, Western Australia 6009, Australia and School of Physics, University of Western Australia, 6009 Australia (Australia); Department of Radiation Oncology, Calvary Mater Newcastle, Waratah, New South Wales 2298 (Australia); Australasian College of Physical Scientists and Engineers in Medicine, Mascot, New South Wales 2020 (Australia); Trans-Tasman Radiation Oncology Group, Calvary Mater Newcastle, New South Wales 2298 (Australia); Institute of Health and Rehabilitation Research, University of Notre Dame, Fremantle, Western Australia 6160 (Australia); Heidelberg Repatriation Hospital, Victoria 3084 (Australia); Department of Physical Sciences, Peter MacCallum Cancer Centre, Victoria 3002 (Australia); Department of Radiation Oncology, Sir Charles Gairdner Hospital, Western Australia 6009, Australia and School of Surgery, University of Western Australia, Western Australia 6009 (Australia); Department of Radiation Oncology, Calvary Mater Newcastle, Waratah, New South Wales 2298, Australia and School of Medicine and Population Health, University of Newcastle, New South Wales 2308 (Australia)

    2011-09-15

    Purpose: To assess dose delivery accuracy to clinically significant points in a realistic patient geometry for two separate pelvic radiotherapy scenarios. Methods: An inhomogeneous pelvic phantom was transported to 36 radiotherapy centers in Australia and New Zealand. The phantom was treated according to Phase III rectal and prostate trial protocols. Point dose measurements were made with thermoluminescent dosimeters (TLDs) and an ionisation chamber. Comprehensive site-demographic, treatment planning, and physical data were collected for correlation with measurement outcomes. Results: Dose delivery to the prescription point for the rectal treatment was consistent with planned dose (mean difference between planned and measured dose - 0.1 {+-} 0.3% std err). Dose delivery in the region of the sacral hollow was consistently higher than planned (+1.2 {+-} 0.2%). For the prostate treatment, dose delivery to the prostate volume was consistent with planned doses (-0.49 {+-} 0.2%) and planned dose uniformity, though with a tendency to underdose the PTV at the prostate-rectal border. Measured out-of-field doses were significantly higher than planned. Conclusions: A phantom based on realistic anatomy and heterogeneity can be used to comprehensively assess the influence of multiple aspects of the radiotherapy treatment process on dose delivery. The ability to verify dose delivery for two trials with a single phantom was advantageous.

  1. Anatomical correlates of quality of life: evidence from voxel-based morphometry.

    Science.gov (United States)

    Takeuchi, Hikaru; Taki, Yasuyuki; Nouchi, Rui; Hashizume, Hiroshi; Sassa, Yuko; Sekiguchi, Atsushi; Kotozaki, Yuka; Nakagawa, Seishu; Nagase, Tomomi; Miyauchi, Carlos Makoto; Kawashima, Ryuta

    2014-05-01

    Quality of life (QOL) has been defined in many ways, and these definitions usually emphasize happiness and satisfaction with life. Health-related problems are known to cause lower QOL. However, the neural mechanisms underlying individual differences in QOL measured by questionnaire (QOLMQ) in young healthy subjects are unknown. QOL is essential to our well-being, and investigation of the neural mechanisms underlying QOL in uncompromised subjects is obviously of great scientific and social interest. We used voxel-based morphometry to investigate the association between regional gray matter volume (rGMV) and QOLMQ across the brain in healthy young adults (age, 21.4 ± 1.8 years) men (n = 88) and women (n = 68) in humans. We found significant negative relationships between QOLMQ and rGMV in a region in the left rostrolateral prefrontal cortex and regions in the dorsal part of the anterior cingulate gyrus and contingent cingulate regions. These findings show that structural variations in regions associated with processing of negative emotions such as fear and anger as well as those associated with evaluation of internally generated information are associated with QOLMQ. These findings suggest that these processes might be related to QOLMQ in healthy young adults. PMID:23671021

  2. Dosimetric intercomparison for multicenter clinical trials using a patient-based anatomic pelvic phantom

    International Nuclear Information System (INIS)

    Purpose: To assess dose delivery accuracy to clinically significant points in a realistic patient geometry for two separate pelvic radiotherapy scenarios. Methods: An inhomogeneous pelvic phantom was transported to 36 radiotherapy centers in Australia and New Zealand. The phantom was treated according to Phase III rectal and prostate trial protocols. Point dose measurements were made with thermoluminescent dosimeters (TLDs) and an ionisation chamber. Comprehensive site-demographic, treatment planning, and physical data were collected for correlation with measurement outcomes. Results: Dose delivery to the prescription point for the rectal treatment was consistent with planned dose (mean difference between planned and measured dose - 0.1 ± 0.3% std err). Dose delivery in the region of the sacral hollow was consistently higher than planned (+1.2 ± 0.2%). For the prostate treatment, dose delivery to the prostate volume was consistent with planned doses (-0.49 ± 0.2%) and planned dose uniformity, though with a tendency to underdose the PTV at the prostate-rectal border. Measured out-of-field doses were significantly higher than planned. Conclusions: A phantom based on realistic anatomy and heterogeneity can be used to comprehensively assess the influence of multiple aspects of the radiotherapy treatment process on dose delivery. The ability to verify dose delivery for two trials with a single phantom was advantageous.

  3. Quality-Aware Estimation of Facial Landmarks in Video Sequences

    DEFF Research Database (Denmark)

    Haque, Mohammad Ahsanul; Nasrollahi, Kamal

    2015-01-01

    Face alignment in video is a primitive step for facial image analysis. The accuracy of the alignment greatly depends on the quality of the face image in the video frames and low quality faces are proven to cause erroneous alignment. Thus, this paper proposes a system for quality aware face alignment by using a Supervised Decent Method (SDM) along with a motion based forward extrapolation method. The proposed system first extracts faces from video frames. Then, it employs a face quality assessment technique to measure the face quality. If the face quality is high, the proposed system uses SDM for facial landmark detection. If the face quality is low the proposed system corrects the facial landmarks that are detected by SDM. Depending upon the face velocity in consecutive video frames and face quality measure, two algorithms are proposed for correction of landmarks in low quality faces by using an extrapolation polynomial. Experimental results illustrate the competency of the proposed method while comparing with the state-of-theart methods including an SDM-based method (from CVPR-2013) and a very recent method (from CVPR-2014) that uses parallel cascade of linear regression (Par-CLR).

  4. Metabolic Predispositions and Increased Risk of Colorectal Adenocarcinoma by Anatomical Location: A Large Population-Based Cohort Study in Norway.

    Science.gov (United States)

    Lu, Yunxia; Ness-Jensen, Eivind; Hveem, Kristian; Martling, Anna

    2015-11-15

    Whether different definitions of metabolic syndrome (MetS) are differently associated with colorectal adenocarcinoma (CA) by anatomical location is unclear. A population-based cohort study, the Cohort of Norway (CONOR) Study, was conducted in Norway from 1995 to 2010. Anthropometric measurements, blood samples, and lifestyle data were collected at recruitment. CAs were identified through linkage to the Norwegian Cancer Register. A composite index of MetS as defined by the International Diabetes Federation (IDF) or/and the National Cholesterol Education Program's Adult Treatment Panel III (ATP III) and single components of MetS, including anthropometric factors, blood pressure, lipids, triglycerides, and glucose, were analyzed. Cox proportional hazards regression was performed to estimate hazard ratios and 95% confidence intervals. Significant associations between single MetS components and CA, except for reduced high-density lipoprotein cholesterol and nonfasting glucose levels, were observed. MetS defined by 2 criteria separately showed a similar association with CA in general, and MetS defined by both the IDF and ATP III showed consistent results. Stronger associations were observed in the proximal colon among men (IDF: hazard ratio (HR) = 1.51, 95% confidence interval (CI): 1.24, 1.84; ATP III: HR = 1.40, 95% CI: 1.15, 1.70) and in the rectum among women (IDF: HR = 1.42, 95% CI: 1.07, 1.89; ATP III: HR = 1.43, 95% CI: 1.08, 1.90). PMID:26511906

  5. Anatomical differences in empathy related brain areas: A voxel-based morphometry study

    Directory of Open Access Journals (Sweden)

    Jean Decety

    2015-02-01

    Full Text Available Understanding empathy from a neuroscientific perspective has taken precedence recently with several fMRI studies associating different brain regions with different components of empathy. A recent meta-analysis across 40 fMRI studies revealed that affective empathy (vicariously sharing others emotions is most often associated with activity in the insula, whereas cognitive empathy (reasoning about others emotions is most often associated with activity in the dorsal anterior cingulate cortex and adjacent dorsomedial prefrontal cortex (dACC/dmPFC; Fan et al., 2011. To date, however, it remains unclear whether individual differences in brain morphometry in these regions underlie different capabilities in affective and cognitive empathy. In order to test this hypothesis, we used voxel-based morphometry (VBM to analyse grey matter density using scores from an established empathy measure (Questionnaire of Cognitive and Affective Empathy; QCAE as regressors. One hundred and seventy-six participants completed the QCAE and underwent MRI in order to acquire a high-resolution, three-dimensional T1-weighted image. A factor analysis of the questionnaire scores revealed two distinct factors of empathy, affective and cognitive, which confirmed the validity of the QCAE. VBM results revealed grey matter density differences associated with the different constructs of empathy, whereby, higher scores of affective empathy were related to greater grey matter density in the insula and higher scores of cognitive empathy were related to greater grey matter density in the dACC/dmPFC. Taken together, the results shown here provide validation for empathy being a multi-component construct, suggesting that affective and cognitive empathy are differentially represented in brain morphometry.

  6. Examining the Variations in the Results of the Hotelling T (2) Test in Case of Changing Baseline Landmarks in the Bookstein Coordinates.

    Science.gov (United States)

    Ercan, Ilker; Sigirli, Deniz; Ozkaya, Guven

    2015-06-01

    In many biological and biomedical investigations, the most effective way to analyze the forms of whole biological organs or organisms is by recording geometric locations of landmark points. If we want to compare shapes, then individuals should be translated, rotated and scaled in such a way that all of the individuals lie in a standard position and are centered. Bookstein conducted this process by choosing two landmarks as reference landmarks. Each individual is translated, rotated and scaled according to these reference landmarks. The aim of the present study was to examine the change in the p values in the case of choosing different baseline landmarks when performing the Hotelling T (2) test, which is commonly used when comparing two sample shape configurations based on Bookstein coordinates. For this purpose, the changes in the p values were investigated in shape configurations that are composed of a different number of landmarks by taking all of the possible paired landmark combinations at different variance levels and sample sizes. As a result of the present study, it was observed that with the increase in the landmark number, the number of possible baseline landmark combinations also increases and, for this reason, a substantial number of variations occur in the p values. Therefore, it is an important to decide which landmarks should be taken as reference landmarks when using the Bookstein coordinates. PMID:26199212

  7. Electronic and film portal images: a comparison of landmark visibility and review accuracy

    International Nuclear Information System (INIS)

    Purpose: To quantitatively compare a scanning liquid ion chamber electronic portal imaging device (SLIC-EPID) and an amorphous silicon flat panel (aSi) EPID with portal film in clinical applications using measures of landmark visibility and treatment review accuracy. Methods and Materials: Six radiation oncologists viewed 39 electronic portal images (EPIs) from the SLIC-EPID, 36 EPIs from the aSi-EPID, and portal films of each of these treatment fields. The physicians rated the clarity of anatomic landmarks in the portal images, and the scores were compared between EPID and film. Nine hundred portal image reviews were performed. EPID and film portal images were acquired with known setup errors in either phantom or cadaver treatments. Physicians identified the errors visually in portal films and with computerized analysis for EPID. Results: There were no statistically significant (p<0.05) differences between film and SLIC-EPID in ratings of landmark clarity. Eleven of 12 landmarks were more visible in aSi-EPID than in film. Translational setup errors were identified with an average accuracy of 2.5 mm in film, compared to 1.5 mm with SLIC-EPID and 1.3 mm with aSi-EPID. Conclusions: Both EPIDs are clinically viable replacements for film, but aSi-EPID represents a significant advancement in image quality over film

  8. The Effect of Electrode Designs Based on the Anatomical Heart Location for the Non-Contact Heart Activity Measurement.

    Science.gov (United States)

    Gi, Sun Ok; Lee, Young-Jae; Koo, Hye Ran; Lee, Seung Pyo; Lee, Kang-Hwi; Kim, Kyeng-Nam; Kang, Seung-Jin; Lee, Joo Hyeon; Lee, Jeong-Whan

    2015-12-01

    This research is an extension of a previous research [1] on the different effects of sensor location that is relatively suitable for heart rate sensing. This research aimed to elucidate the causes of wide variations in heart rate measurements from the same sensor position among subjects, as observed in previous research [1], and to enhance designs of the inductive textile electrode to overcome these variations. To achieve this, this study comprised two parts: In part 1, X-ray examinations were performed to determine the cause of the wide variations noted in the findings from previous research [1], and we found that at the same sensor position, the heart activity signal differed with slight differences in the positions of the heart of each subject owing to individual differences in the anatomical heart location. In part 2, three types of dual-loop-type textile electrodes were devised to overcome variations in heart location that were confirmed in part 1 of the study. The variations with three types of sensor designs were compared with that with a single-round type of electrode design, by using computer simulation and by performing a t-test on the data obtained from the experiments. We found that the oval-oval shaped, dual-loop-type textile electrode was more suitable than the single round type for determining morphological characteristics as well as for measuring appropriate heart activity signals. Based on these results, the oval-oval, dual-loop-type was a better inductive textile electrode that more effectively overcomes individual differences in heart location during heart activity sensing based on the magnetic-induced conductivity principle. PMID:26490149

  9. Which Tibial Tray Design Achieves Maximum Coverage and Ideal Rotation: Anatomic, Symmetric, or Asymmetric? An MRI-based study.

    Science.gov (United States)

    Stulberg, S David; Goyal, Nitin

    2015-10-01

    Two goals of tibial tray placement in TKA are to maximize coverage and establish proper rotation. Our purpose was to utilize MRI information obtained as part of PSI planning to determine the impact of tibial tray design on the relationship between coverage and rotation. MR images for 100 consecutive knees were uploaded into PSI software. Preoperative planning software was used to evaluate 3 different tray designs: anatomic, symmetric, and asymmetric. Approximately equally good coverage was achieved with all three trays. However, the anatomic compared to symmetric/asymmetric trays required less malrotation (0.3° vs 3.0/2.4°; P < 0.001), with a higher proportion of cases within 5° of neutral (97% vs 73/77%; P < 0.001). In this study, the anatomic tibia optimized the relationship between coverage and rotation. PMID:25976595

  10. TINA manual landmarking tool: software for the precise digitization of 3D landmarks

    Directory of Open Access Journals (Sweden)

    Schunke Anja C

    2012-04-01

    Full Text Available Abstract Background Interest in the placing of landmarks and subsequent morphometric analyses of shape for 3D data has increased with the increasing accessibility of computed tomography (CT scanners. However, current computer programs for this task suffer from various practical drawbacks. We present here a free software tool that overcomes many of these problems. Results The TINA Manual Landmarking Tool was developed for the digitization of 3D data sets. It enables the generation of a modifiable 3D volume rendering display plus matching orthogonal 2D cross-sections from DICOM files. The object can be rotated and axes defined and fixed. Predefined lists of landmarks can be loaded and the landmarks identified within any of the representations. Output files are stored in various established formats, depending on the preferred evaluation software. Conclusions The software tool presented here provides several options facilitating the placing of landmarks on 3D objects, including volume rendering from DICOM files, definition and fixation of meaningful axes, easy import, placement, control, and export of landmarks, and handling of large datasets. The TINA Manual Landmark Tool runs under Linux and can be obtained for free from http://www.tina-vision.net/tarballs/.

  11. Agreement between anatomic and ultrasound measurements of femoral trochlear depth

    DEFF Research Database (Denmark)

    Miles, James Edward; Westrup, Ulrik; Eriksen, Thomas

    Assessments of trochlear depth for patients with medial patellar luxation have traditionally been estimated from skyline radiographs or visually during surgery. Ultrasound offers a non-invasive evaluation method which could avoid the need for arthrotomy. We compared anatomic, radiographic and ult...... respective DICOM files which restricts ultrasonographic landmark resolution. Further work on quantifying interobserver variation and repeat measurement variation is required to ensure confidence in this technique....

  12. Anatomical Factors Influencing Pneumatization of the Petrous Apex

    OpenAIRE

    Lee, Dong-Hee; Kim, Min-ju; Lee, Seunghun; Choi, Hana

    2015-01-01

    Objectives Aim of the present study was to define the relationship between petrous apex pneumatization and the nearby major anatomical landmarks using temporal bone computed tomography (CT) images. Methods This retrospective, Institutional Review Board-approved study analyzed CT images of 84 patients that showed normal findings bilaterally. Pneumatization of the petrous apex was classified using two methods. Eight parameters were as follows: angle between the posterior cranial fossa and inter...

  13. Evaluation of sexual history-based screening of anatomic sites for chlamydia trachomatis and neisseria gonorrhoeae infection in men having sex with men in routine practice

    Directory of Open Access Journals (Sweden)

    Jansen Casper L

    2011-07-01

    Full Text Available Abstract Background Sexually transmitted infection (STI screening programmes are implemented in many countries to decrease burden of STI and to improve sexual health. Screening for Chlamydia trachomatis and Neisseria gonorrhoeae has a prominent role in these protocols. Most of the screening programmes concerning men having sex with men (MSM are based on opportunistic urethral testing. In The Netherlands, a history-based approach is used. The aim of this study is to evaluate the protocol of screening anatomic sites for C. trachomatis and N. gonorrhoeae infection based on sexual history in MSM in routine practice in The Netherlands. Methods All MSM visiting the clinic for STI in The Hague are routinely asked about their sexual practice during consulting. As per protocol, tests for urogenital, oropharyngeal and anorectal infection are obtained based on reported site(s of sexual contact. All consultations are entered into a database as part of the national STI monitoring system. Data of an 18 months period were retrieved from this database and analysed. Results A total of 1455 consultations in MSM were registered during the study period. The prevalence of C. trachomatis and N. gonorrhoeae per anatomic site was: urethral infection 4.0% respectively and 2.8%, oropharynx 1.5% and 4.2%, and anorectum 8.2% and 6.0%. The majority of chlamydia cases (72% involved a single anatomic site, which was especially manifest for anorectal infections (79%, while 42% of gonorrhoea cases were single site. Twenty-six percent of MSM with anorectal chlamydia and 17% with anorectal gonorrhoea reported symptoms of proctitis; none of the oropharyngeal infections were symptomatic. Most cases of anorectal infection (83% and oropharyngeal infection (100% would have remained undiagnosed with a symptom-based protocol. Conclusions The current strategy of sexual-history based screening of multiple anatomic sites for chlamydia and gonorrhoea in MSM is a useful and valid guideline which is to be preferred over a symptom-based screening protocol.

  14. The accuracy of a designed software for automated localization of craniofacial landmarks on CBCT images

    International Nuclear Information System (INIS)

    Two-dimensional projection radiographs have been traditionally considered the modality of choice for cephalometric analysis. To overcome the shortcomings of two-dimensional images, three-dimensional computed tomography (CT) has been used to evaluate craniofacial structures. However, manual landmark detection depends on medical expertise, and the process is time-consuming. The present study was designed to produce software capable of automated localization of craniofacial landmarks on cone beam (CB) CT images based on image registration and to evaluate its accuracy. The software was designed using MATLAB programming language. The technique was a combination of feature-based (principal axes registration) and voxel similarity-based methods for image registration. A total of 8 CBCT images were selected as our reference images for creating a head atlas. Then, 20 CBCT images were randomly selected as the test images for evaluating the method. Three experts twice located 14 landmarks in all 28 CBCT images during two examinations set 6 weeks apart. The differences in the distances of coordinates of each landmark on each image between manual and automated detection methods were calculated and reported as mean errors. The combined intraclass correlation coefficient for intraobserver reliability was 0.89 and for interobserver reliability 0.87 (95% confidence interval, 0.82 to 0.93). The mean errors of all 14 landmarks were <4 mm. Additionally, 63.57% of landmarks had a mean error of <3 mm compared with manual detection (gold standard method). The accuracy of our approach for automated localization of craniofacial landmarks, which was based on combining feature-based and voxel similarity-based methods for image registration, was acceptable. Nevertheless we recommend repetition of this study using other techniques, such as intensity-based methods

  15. The Mandibular Landmarks about the Facial Artery and Vein with Multidetector Computed Tomography Angiography (MDCTA): an Anatomical and Radiological Morphometric Study / Puntos de Referencia de la Mandíbula Relacionados a la Arteria y Vena Facial con Angiografía por Tomografía Computarizada Multidetector (ATCM): un Estudio Morfométrico Anatómico y Radiológico

    Scientific Electronic Library Online (English)

    Aynur Emine, Cicekcibasi; Mehmet Tugrul, Yilmaz; Demet, Kiresi; Muzaffer, Seker.

    2012-06-01

    Full Text Available El objetivo de este estudio fue investigar el curso de los vasos faciales de acuerdo con varios puntos de referencias mandibulares en sujetos vivos mediante angiografía por tomografía computarizada multidetector (ATCM) para determinar si éstos están relacionados con el sexo y el lado. El estudio se [...] llevó a cabo en el Departamento de Radiología, Facultad de Medicina de Meram en Necmettin Erbakan (Konya, Turkey). En total, sesenta caras de 30 sujetos (15 hombres y 15 mujeres), que presentaban síntomas y signos de la enfermedad vascular fueron evaluados para explorar los vasos faciales por ATCM. Los parámetros sobre los vasos faciales se midieron en relación a puntos de referencia (ángulo de la mandíbula, proceso mental, foramen mental y línea mediana facial). La distancia desde el punto en el que la arteria facial aparece por primera vez en el margen inferior de la mandíbula hasta el ángulo mandibular de la arteria facial derecha y izquierda fueron 3,53±0,66 cm y 3,31±0,73 cm en hombres, respectivamente. En mujeres fueron 2,91±0,52 cm y 3,35± 0,48 cm. La ATCM es un examen nuevo, poderoso, seguro y no invasivo para demostrar la vascularización de la cabeza. Las estructuras óseas y la morfología de los vasos vecinos pueden ser evaluados por esta técnica en casos de trauma con sospecha de lesiones de los vasos y se puede considerar de selección en pacientes para realizar cirugías de colgajo. Abstract in english The aim of this study was to investigate the course of the facial vessels according to several mandibular landmarks in living individuals using multidetector computed tomography angiography (MDCTA) to determine these related to sex and side. This study was conducted in the Radiology Department, Mera [...] m Faculty of Medicine, Necmettin Erbakan University (Konya, Turkey). In total, sixty faces from 30 specimens (15 males and 15 females) with symptoms and signs of vascular disease were evaluated for the facial vessels by MDCTA scan. The facial vessel parameters were measured according to the reference points (mandibular angle, mental protuberance, mental foramen and facial midline). The distance from the point at which the facial artery first appears in the lower margin of the mandible to the mandibular angle for right and left facial artery were observed as 3.53±0.66 cm and 3.31±0.73 cm in males, respectively. These distances were determined as 2.91±0.52 cm and 3.35±0.48 cm in females. MDCTA is a new, powerful, safe and noninvasive test to demonstrate the vasculature of the head. Bony structures and neighboring vessel morphology can be evaluated by this technique in cases of trauma with suspected vessel injuries and when considering patient selection for flap surgery.

  16. Anatomic Total Shoulder System

    Medline Plus

    Full Text Available ... In a few moments, you'll be able to watch a live global AP anatomic total shoulder ... neck, angle, and version variability which allows adaptability to a patient's unique anatomical makeup. Dr. Gerald R. ...

  17. Automated landmark-guided deformable image registration

    Science.gov (United States)

    Kearney, Vasant; Chen, Susie; Gu, Xuejun; Chiu, Tsuicheng; Liu, Honghuan; Jiang, Lan; Wang, Jing; Yordy, John; Nedzi, Lucien; Mao, Weihua

    2015-01-01

    The purpose of this work is to develop an automated landmark-guided deformable image registration (LDIR) algorithm between the planning CT and daily cone-beam CT (CBCT) with low image quality. This method uses an automated landmark generation algorithm in conjunction with a local small volume gradient matching search engine to map corresponding landmarks between the CBCT and the planning CT. The landmarks act as stabilizing control points in the following Demons deformable image registration. LDIR is implemented on graphics processing units (GPUs) for parallel computation to achieve ultra fast calculation. The accuracy of the LDIR algorithm has been evaluated on a synthetic case in the presence of different noise levels and data of six head and neck cancer patients. The results indicate that LDIR performed better than rigid registration, Demons, and intensity corrected Demons for all similarity metrics used. In conclusion, LDIR achieves high accuracy in the presence of multimodality intensity mismatch and CBCT noise contamination, while simultaneously preserving high computational efficiency.

  18. Landmark papers on photorefractive nonlinear optics

    CERN Document Server

    Yeh, Pochi

    1995-01-01

    This book, intended for students, researchers and engineers, is a collection of classic papers on photorefractive nonlinear optics. Included are landmark papers on fundamental photorefractive phenomena, two-wave mixing, four-wave mixing, phase conjugators and resonators, material growth and physics, and applications in image processing, optical storage and optical computing.

  19. Validation of landmark sets and their use for registration in mouse brain imaging

    Directory of Open Access Journals (Sweden)

    Marina Sergejeva

    2010-06-01

    Full Text Available In the time when genetic engineering is flourishing, and numerous strains of mutant mice are being created for research purposes, a world-wide accessible reference system which would enable comparison of the data of various types from different working groups is very desirable. Several attempts have been made for such mouse brain atlases ranging from the gold standard of the Paxinos printed atlas (2nd edition 2001 to ABA (www.brain-map.org etc. The INCF (incf.org/ has launched the Digital Atlasing Program (incf.org/core/programs/atlasing which came up with the Waxholm space (WHS: 2008, which is an up-to-date computer-based common reference space for adult C57BL/6J mice. This reference space, available to the public, consists of very high resolution undistorted MRI datasets of different contrasts (T1: 21,5 µm, T2, T2*, 43 µm together with Nissl histology (20 µm of the very same specimen, all fully 3D from A. Johnson (Duke, www.civm.duhs.duke.edu/. Very recently, population based datasets including DTI have been made available by A. Johnson (www.civm.duhs.duke.edu/neuro200902/index.html. One desirable application of a computerized digital atlas is to bring one’s own data into this reference system to gain full advantage of the information available in the system. This process is called registration. Fully automatic registration processes only exist for very limited use of datasets with hard constrains (dimensionality, modality, contrast etc.. Moreover, the parameterization of these algorithms is complex and high computational power (up to several hours is needed. An alternative approach, which I is much faster, II can be performed by everybody, III leads to sufficient accuracy for many applications, is a registration based on landmarks or fiducials. In imaging technology, a fiducial is part of an image serving as a point of reference i.e. characteristic internal anatomic structure of the brain easily identified. Practically and to enhance the spatial precision, the fiducials are often reduced to a single point (see Fig. 1. Defining a corresponding set of fiducials in a source and target (reference dataset determines the transformation of the source to the target dataset. Moreover, this landmark based registration may first, enhance performance of the computational intense automatic registration and second, these fiducials allow for validation of any other registration procedure. Therefore, the aim of this study is to identify set(s of fiducials primarily allowing the registration of any 3D datasets to WHS. These should be unambiguously recognizable: • to different individuals • in different image modalities (T1, T2, T2* • in various specimens • in different cutting directions • in different image resolutions • in various mouse strains Consequently, we started with "medium" resolution MR datasets (T1, T2, T2*, 256x256x128, 80 µm. Using ImageJ (rsbweb.nih.gov/ij/index.html and its point identification tool, anatomical experts defined an initial set of fiducials (T1: 36, T2: 65, T2*: 51. Next a group of 13 subjects (among them anatomical novice, physicists, vets and biologists identified these landmarks on the same dataset, using a guide to find and set the fiducials. We achieved a very high precision of around 1.5 voxel deviation across all fiducials. In addition, the same group of people had to identify these fiducials on different datasets of the same mouse strain. In this case, for T1-90 %, T2-100%, and T2*-97% of these same fiducials could be found. A web-based version of our fiducial point effort is online to encourage user participation (http://smartatlas.crbs.ucsd.edu:8080 /mapserver-services/pages/imageviewer/incf1.html. This study allows us to get insight into accuracy of manually identifiable fiducials, and therefore their reliability. Establishing an easy to use landmark registration to WHS should facilitate cooperation of mouse imagers all over the world.

  20. TINA manual landmarking tool: software for the precise digitization of 3D landmarks

    OpenAIRE

    Schunke Anja C; Bromiley Paul A; Tautz Diethard; Thacker Neil A

    2012-01-01

    Abstract Background Interest in the placing of landmarks and subsequent morphometric analyses of shape for 3D data has increased with the increasing accessibility of computed tomography (CT) scanners. However, current computer programs for this task suffer from various practical drawbacks. We present here a free software tool that overcomes many of these problems. Results The TINA Manual Landmarking Tool was developed for the digitization of 3D data sets. It enables the generation of a modifi...

  1. 36 CFR 62.7 - Natural landmark modifications.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Natural landmark... INTERIOR NATIONAL NATURAL LANDMARKS PROGRAM § 62.7 Natural landmark modifications. (a) Determination of need for modifications. After designation, the modification of the boundaries of a natural...

  2. Ultrasound of the elbow: A systematic approach using bony landmarks

    International Nuclear Information System (INIS)

    The use of bony landmarks can be helpful in performing an ultrasound study of the elbow. We discuss bony landmarks that can be used for evaluation of the common extensor tendon, ulnar collateral ligament and common flexor tendon, coronoid and olecranon fossa, ulnar nerve, and biceps tendon. We discuss bony landmarks for each of these structures.

  3. Anatomical imaging for radiotherapy

    International Nuclear Information System (INIS)

    The goal of radiation therapy is to achieve maximal therapeutic benefit expressed in terms of a high probability of local control of disease with minimal side effects. Physically this often equates to the delivery of a high dose of radiation to the tumour or target region whilst maintaining an acceptably low dose to other tissues, particularly those adjacent to the target. Techniques such as intensity modulated radiotherapy (IMRT), stereotactic radiosurgery and computer planned brachytherapy provide the means to calculate the radiation dose delivery to achieve the desired dose distribution. Imaging is an essential tool in all state of the art planning and delivery techniques: (i) to enable planning of the desired treatment, (ii) to verify the treatment is delivered as planned and (iii) to follow-up treatment outcome to monitor that the treatment has had the desired effect. Clinical imaging techniques can be loosely classified into anatomic methods which measure the basic physical characteristics of tissue such as their density and biological imaging techniques which measure functional characteristics such as metabolism. In this review we consider anatomical imaging techniques. Biological imaging is considered in another article. Anatomical imaging is generally used for goals (i) and (ii) above. Computed tomography (CT) has been the mainstay of anatomical treatment planning for many years, enabling some delineation of soft tissue as well as radiation attenuation estimation for dose prediction. Magnetic resonance imaging is fast becoming widespread alongside CT, enabling superior soft-tissue visualization. Traditionally scanning for treatment planning has relied on the use of a single snapshot scan. Recent years have seen the development of techniques such as 4D CT and adaptive radiotherapy (ART). In 4D CT raw data are encoded with phase information and reconstructed to yield a set of scans detailing motion through the breathing, or cardiac, cycle. In ART a set of scans is taken on different days. Both allow planning to account for variability intrinsic to the patient. Treatment verification has been carried out using a variety of technologies including: MV portal imaging, kV portal/fluoroscopy, MVCT, conebeam kVCT, ultrasound and optical surface imaging. The various methods have their pros and cons. The four x-ray methods involve an extra radiation dose to normal tissue. The portal methods may not generally be used to visualize soft tissue, consequently they are often used in conjunction with implanted fiducial markers. The two CT-based methods allow measurement of inter-fraction variation only. Ultrasound allows soft-tissue measurement with zero dose but requires skilled interpretation, and there is evidence of systematic differences between ultrasound and other data sources, perhaps due to the effects of the probe pressure. Optical imaging also involves zero dose but requires good correlation between the target and the external measurement and thus is often used in conjunction with an x-ray method. The use of anatomical imaging in radiotherapy allows treatment uncertainties to be determined. These include errors between the mean position at treatment and that at planning (the systematic error) and the day-to-day variation in treatment set-up (the random error). Positional variations may also be categorized in terms of inter- and intra-fraction errors. Various empirical treatment margin formulae and intervention approaches exist to determine the optimum strategies for treatment in the presence of these known errors. Other methods exist to try to minimize error margins drastically including the currently available breath-hold techniques and the tracking methods which are largely in development. This paper will review anatomical imaging techniques in radiotherapy and how they are used to boost the therapeutic benefit of the treatment. (topical review)

  4. Landmarks GIScience for intelligent services

    CERN Document Server

    Richter, Kai-Florian

    2014-01-01

    Summarizes the latest studies on car navigation services, mobile location-based services, museum guides, tourist guides, public transport planners and recent voice interfaces to mobile devices Broadens understanding of spatial applications for smart phones Contains numerous exercises and examples to reinforce concepts

  5. Cancer Prevalence - SEER Landmark Studies

    Science.gov (United States)

    SEER is an authoritative source of information on cancer incidence and survival in the United States. SEER currently collects and publishes cancer incidence and survival data from population-based cancer registries covering approximately 28 percent of the U.S. population.

  6. Historical Landmark Studies - About SEER

    Science.gov (United States)

    SEER is an authoritative source of information on cancer incidence and survival in the United States. SEER currently collects and publishes cancer incidence and survival data from population-based cancer registries covering approximately 28 percent of the U.S. population.

  7. Second Cancers - SEER Landmark Studies

    Science.gov (United States)

    SEER is an authoritative source of information on cancer incidence and survival in the United States. SEER currently collects and publishes cancer incidence and survival data from population-based cancer registries covering approximately 28 percent of the U.S. population.

  8. CISNET: Breast Cancer Landmark Study

    Science.gov (United States)

    After remaining relatively constant for many years, breast cancer mortality in the United States decreased by a dramatic 24% from 1989 to 2000. CISNET investigators initiated a joint comparative modeling effort among seven groups to determine the contributions of mammography and adjuvant therapy to this decline. While the benefits of adjuvant therapy were more settled, controversy regarding the benefits of mammography screening persisted due to uneven results and continuing criticism of the controlled trials on which the mortality benefits had been based.

  9. Landmarking and feature localization in spine x-rays

    Science.gov (United States)

    Long, L. Rodney; Thoma, George R.

    2001-10-01

    The general problem of developing algorithms for the automated or computer-assisted indexing of images by structural contents is a significant research challenge. This is particularly so in the case of biomedical images, where the structures of interest are commonly irregular, overlapping, and partially occluded. Examples are the images created by digitizing film x-rays of the human cervical and lumbar spines. We have begun work toward the indexing of 17 000 such spine images for features of interest in the osteoarthritis and vertebral morphometry research communities. This work requires the segmentation of the images into vertebral structures with sufficient accuracy to distinguish pathology on the basis of shape, labeling of the segmented structures by proper anatomical name, and classification of the segmented, labeled structures into groups corresponding to high level semantic features of interest, using training data provided by biomedical experts. In this paper, we provide a technical characterization of the cervical spine images and the biomedical features of interest, describe the evolving technical approach for the segmentation and indexing problem, and provide results of algorithms to acquire basic landmark data and localization of spine regions in the images.

  10. Using local symmetry for landmark selection

    OpenAIRE

    Kootstra, Geert; de Jong, Sjoerd; Schomaker, Lambert R. B.

    2009-01-01

    Most visual Simultaneous Localization And Mapping (SLAM) methods use interest points as landmarks in their maps of the environment. Often the interest points are detected using contrast features, for instance those of the Scale Invariant Feature Transform (SIFT). The SIFT interest points, however, have problems with stability, and noise robustness. Taking our inspiration from human vision, we therefore propose the use of local symmetry to select interest points. Our method, the MUlti-scale Sy...

  11. Selenium-based digital radiography of the cervical spine. Comparison with screen-film radiography for the depiction of anatomic details

    International Nuclear Information System (INIS)

    Purpose: To compare selenium-based digital radiography with conventional screen-film radiography of the cervical spine. Materials and Methods: In a prospective study X-ray images of the cervical spine were obtained in 25 patients using selenium-based digital radiography and conventional screen-film radiography. All images were clinically indicated. Selenium-based digital radiography and conventional screen-film radiography were used in a randomized order. Four radiologists independently evaluated all 50 examinations for the visibility of 76 anatomic details according to a five-level confidence scale (1=not visible, 5=very good visibility). From the evaluation of these anatomic details scores for the upper and middle cervical spine, the cervicothoracic junction and the cervical soft tissues were calculated. The scores for selenium-based digital radiography and conventional screen-film radiography were compared using Wilcoxon's signed rank test. Results: From a total of 15,200 observations (608 per patient) the following scores were calculated for selenium-based digital radiography and for screen-film radiography, respectively: Upper cervical spine 3.88 and 3.94; middle cervical spine 4.60 and 4.48; cervico-thoracic junction 3.64 and 2.62; cervical soft tissue 4.47 and 3.46. The differences between the last two scores were statistically significant (p<0.05). Conclusion: the use of selenium-based digital radiography is superior to conventional screen-film radiography in the depiction of anatomic details of the cervicothoracic junction and the cervical soft tissues. (orig.)

  12. Tools for quantitative form description; an evaluation of different software packages for semi-landmark analysis

    Science.gov (United States)

    Houssaye, Alexandra; Herrel, Anthony; Fabre, Anne-Claire; Cornette, Raphael

    2015-01-01

    The challenging complexity of biological structures has led to the development of several methods for quantitative analyses of form. Bones are shaped by the interaction of historical (phylogenetic), structural, and functional constrains. Consequently, bone shape has been investigated intensively in an evolutionary context. Geometric morphometric approaches allow the description of the shape of an object in all of its biological complexity. However, when biological objects present only few anatomical landmarks, sliding semi-landmarks may provide good descriptors of shape. The sliding procedure, mandatory for sliding semi-landmarks, requires several steps that may be time-consuming. We here compare the time required by two different software packages (‘Edgewarp’ and ‘Morpho’) for the same sliding task, and investigate potential differences in the results and biological interpretation. ‘Morpho’ is much faster than ‘Edgewarp,’ notably as a result of the greater computational power of the ‘Morpho’ software routines and the complexity of the ‘Edgewarp’ workflow. Morphospaces obtained using both software packages are similar and provide a consistent description of the biological variability. The principal differences between the two software packages are observed in areas characterized by abrupt changes in the bone topography. In summary, both software packages perform equally well in terms of the description of biological structures, yet differ in the simplicity of the workflow and time needed to perform the analyses. PMID:26618086

  13. Anatomically shaped cranial collimation (ACC) for lateral cephalometric radiography: a technical report.

    Science.gov (United States)

    Hoogeveen, R C; van der Stelt, P F; Berkhout, W E R

    2014-01-01

    Lateral cephalograms in orthodontic practice display an area cranial of the base of the skull that is not required for diagnostic evaluation. Attempts have been made to reduce the radiation dose to the patient using collimators combining the shielding of the areas above the base of the skull and below the mandible. These so-called "wedge-shaped" collimators have not become standard equipment in orthodontic offices, possibly because these collimators were not designed for today's combination panoramic-cephalometric imaging systems. It also may be that the anatomical variability of the area below the mandible makes this area unsuitable for standardized collimation. In addition, a wedge-shaped collimator shields the cervical vertebrae; therefore, assessment of skeletal maturation, which is based on the stage of development of the cervical vertebrae, cannot be performed. In this report, we describe our investigations into constructing a collimator to be attached to the cephalostat and shield the cranial area of the skull, while allowing the visualization of diagnostically relevant structures and markedly reducing the size of the irradiated area. The shape of the area shielded by this "anatomically shaped cranial collimator" (ACC) was based on mean measurements of cephalometric landmarks of 100 orthodontic patients. It appeared that this collimator reduced the area of irradiation by almost one-third without interfering with the imaging system or affecting the quality of the image. Further research is needed to validate the clinical efficacy of the collimator. PMID:24170799

  14. Iliohypogastric/ilioinguinal nerve block in inguinal hernia repair for postoperative pain management: comparison of the anatomical landmark and ultrasound guided techniques / Bloqueo de los nervios ileohipogástrico/ilioinguinal en corrección de hernia inguinal para el tratamiento del dolor en el postoperatorio: comparación entre la técnica de marcas anatómicas y la guiada por ultrasonido / Bloqueio dos nervos ílio-hipogástrico/ilioinguinal em correção de hérnia inguinal para tratamento da dor no pós-operatório: comparação entre a técnica de marcos anatômicos e a guiada por ultrassom

    Scientific Electronic Library Online (English)

    Abdurrahman, Demirci; Esra Mercanoglu, Efe; Gürkan, Türker; Alp, Gurbet; Fatma Nur, Kaya; Ali, Anil; & #304; lker, Çimen.

    2014-09-01

    Full Text Available Objetivo: Comparar a eficácia de bloqueios dos nervos ílio-hipogástrico/ilioinguinal feitos com a técnica guiada por ultrassom e a de marcos anatômicos para o manejo da dor no pós-operatório em casos de herniorrafia inguinal em adultos. Métodos: Foram randomicamente divididos 40 pacientes, estado f [...] ísico ASA I-II, em dois grupos iguais: nos grupos AN (técnica de marcos anatômicos) e US (técnica guiada por ultrassom), o bloqueio dos nervos ílio-hipogástrico/ilioinguinal foi feito com 20 mL de levobupivacaína a 0,5% antes da cirurgia com as técnicas especificadas. Escore de dor na avaliação pós-operatória, tempo de primeira mobilização, tempo de internação hospitalar, escore de satisfação com a analgesia no pós-operatório, efeitos colaterais induzidos por opiáceos e complicações relacionadas ao bloqueio foram avaliados durante 24 horas de pós-operatório. Resultados: Escores EVAem repouso na sala de recuperação e todos os valores clínicos durante o acompanhamento foram significativamente menores no grupo ultrassom (p Abstract in spanish Objetivo: El objetivo de este estudio fue comparar la eficacia de bloqueos de los nervios ileohipogástrico/ilioinguinal realizados con la técnica guiada por ultrasonido y la de marca anatómicas para el manejo del dolor en el postoperatorio en casos de herniorrafia inguinal en adultos. Métodos: 40 p [...] acientes, estado físico ASA I-II, fueron aleatoriamente divididos en 2 grupos iguales: grupos con técnica de marcas anatómicas) y grupo con técnica guiada por ultrasonido. El bloqueo de los nervios iliohipogástrico/ilioinguinal fue realizado con 20 mL de levobupivacaína al 0,5% antes de la cirugía con las técnicas especificadas. La puntuación de dolor en la evaluación postoperatoria, tiempo de primera movilización, tiempo de ingreso hospitalario, puntuación de satisfacción con la analgesia en el postoperatorio, efectos colaterales inducidos por opiáceos y complicaciones relacionadas con el bloqueo fueron evaluados durante 24 h de postoperatorio. Resultados: Las puntuaciones EVA en reposo en la sala de recuperación y todos los valores clínicos durante el seguimiento fueron significativamente menores en el grupo con técnica guiada por ultrasonido (p Abstract in english Objectives: The purpose of this study is to compare the efficacy of iliohypogastric/ilioinguinal nerve blocks performed with the ultrasound guided and the anatomical landmark techniques for postoperative pain management in cases of adult inguinal herniorrhaphy. Methods: 40 patients, ASA I-II status [...] were randomized into two groups equally: in Group AN (anatomical landmark technique) and in Group ultrasound (ultrasound guided technique), iliohypogastric/ilioinguinal nerve block was performed with 20 ml of 0.5% levobupivacaine prior to surgery with the specified techniques. Pain score in postoperative assessment, first mobilization time, duration of hospital stay, score of postoperative analgesia satisfaction, opioid induced side effects and complications related to block were assessed for 24 h postoperatively. Results: VAS scores at rest in the recovery room and all the clinical follow-up points were found significantly less in Group ultrasound (p

  15. Midline Incisional Hernia. Anatomical Repairs for the Treatment with Prothesis

    Directory of Open Access Journals (Sweden)

    Madeo, Sergio Damián

    2012-09-01

    Full Text Available 77% of the incisional hernias are located in the midline of the anterior abdominal wall. As a reinforcement of this surgical intervention, the use of a prothesis has been proposed. It’s of main concern the proper knowledge of the anatomical landmarks to perform the colocation of a prothesis in an intermuscular region. The objective of this work is to describe the anatomical landmarks for the colocation of the prothesis in the “retro-rectal intravainal space” during the treatment of midline incisional hernias. A bibliographic and retrospective analysis of the patients treated by the Ponka technique was made, emphasizing on the description of the anatomical landmarks and the technical complications recorded along the period of January 2002 – January 2012. The anatomical and surgical findings are analyzed in this work. On the therapeutic point of view, 431 surgical interventions where effectuated by the use of the Ponka technique, 253 of this group where women with an average age of 41 years old. In 194 cases, transaction of aponeurosis of external oblique muscle was made. The medial edge of the aponeurosis of the rectal muscle was dissected and the posterior space of the muscle was also dissected. In all cases, the superior and inferior epigastric vessels where identified. The polypropylene mesh was located with stitches in a “U” pattern; reabsorbable string was used, in the anterior region of the lateral sector. The medial edge of the aponeurosis of the rectal muscle was sutured. The Ponka technique is an easy and reproductible technique, with a short learning curve. The dissection of the aponeurosis of the rectal muscle, the placement of the mesh and the posterior suture are easy surgical interventions. By this technique, the objectives established by Shell and other authors are accomplished in the treatment of midline medial incisional hernia.

  16. Basic Restriction and Reference Level in Anatomically-based Japanese Models for Low-Frequency Electric and Magnetic Field Exposures

    Science.gov (United States)

    Takano, Yukinori; Hirata, Akimasa; Fujiwara, Osamu

    Human exposed to electric and/or magnetic fields at low frequencies may cause direct effect such as nerve stimulation and excitation. Therefore, basic restriction is regulated in terms of induced current density in the ICNIRP guidelines and in-situ electric field in the IEEE standard. External electric or magnetic field which does not produce induced quantities exceeding the basic restriction is used as a reference level. The relationship between the basic restriction and reference level for low-frequency electric and magnetic fields has been investigated using European anatomic models, while limited for Japanese model, especially for electric field exposures. In addition, that relationship has not well been discussed. In the present study, we calculated the induced quantities in anatomic Japanese male and female models exposed to electric and magnetic fields at reference level. A quasi static finite-difference time-domain (FDTD) method was applied to analyze this problem. As a result, spatially averaged induced current density was found to be more sensitive to averaging algorithms than that of in-situ electric field. For electric and magnetic field exposure at the ICNIRP reference level, the maximum values of the induced current density for different averaging algorithm were smaller than the basic restriction for most cases. For exposures at the reference level in the IEEE standard, the maximum electric fields in the brain were larger than the basic restriction in the brain while smaller for the spinal cord and heart.

  17. Referential framework for transcranial anatomical correspondence for fNIRS based on manually traced sulci and gyri of an infant brain.

    Science.gov (United States)

    Matsui, Mie; Homae, Fumitaka; Tsuzuki, Daisuke; Watanabe, Hama; Katagiri, Masatoshi; Uda, Satoshi; Nakashima, Mitsuhiro; Dan, Ippeita; Taga, Gentaro

    2014-03-01

    Functional near infrared spectroscopy (fNIRS), which is compact, portable, and tolerant of body movement, is suitable for monitoring infant brain functions. Nevertheless, fNIRS also poses a technical problem in that it cannot provide structural information. Supplementation with structural magnetic resonance images (MRI) is not always feasible for infants who undergo fNIRS measurement. Probabilistic registration methods using an MRI database instead of subjects' own MRIs are optimized for adult studies and offer only limited resources for infant studies. To overcome this, we used high-quality infant MRI data for a 12-month-old infant and manually delineated segmented gyri from among the highly visible macroanatomies on the lateral cortical surface. These macroanatomical regions are primarily linked to the spherical coordinate system based on external cranial landmarks, and further to traditional 10-20-based head-surface positioning systems. While macroanatomical structures were generally comparable between adult and infant atlases, differences were found in the parietal lobe, which was positioned posteriorly at the vertex in the infant brain. The present study provides a referential framework for macroanatomical analyses in infant fNIRS studies. With this resource, multichannel fNIRS functional data could be analyzed in reference to macroanatomical structures through virtual and probabilistic registrations without acquiring subject-specific MRIs. PMID:24445146

  18. A study on the reproducibility of cephalometric landmarks when undertaking a three-dimensional (3D) cephalometric analysis

    Science.gov (United States)

    Llamas, José M.; Cibrián, Rosa; Gandia, José L.; Paredes, Vanessa

    2012-01-01

    Objectives: Cone Beam Computerized Tomography (CBCT) allows the possibility of modifying some of the diagnostic tools used in orthodontics, such as cephalometry. The first step must be to study the characteristics of these devices in terms of accuracy and reliability of the most commonly used landmarks. The aims were 1- To assess intra and inter-observer reliability in the location of anatomical landmarks belonging to hard tissues of the skull in images taken with a CBCT device, 2- To determine which of those landmarks are more vs. less reliable and 3- To introduce planes of reference so as to create cephalometric analyses appropriated to the 3D reality. Study design: Fifteen patients who had a CBCT (i-CAT®) as a diagnostic register were selected. To assess the reproducibility on landmark location and the differences in the measurements of two observers at different times, 41 landmarks were defined on the three spatial axes (X,Y,Z) and located. 3.690 measurements were taken and, as each determination has 3 coordinates, 11.070 data were processed with SPSS® statistical package. To discover the reproducibility of the method on landmark location, an ANOVA was undertaken using two variation factors: time (t1, t2 and t3) and observer (Ob1 and Ob2) for each axis (X, Y and Z) and landmark. The order of the CBCT scans submitted to the observers (Ob1, Ob2) at t1, t2, and t3, were different and randomly allocated. Multiple comparisons were undertaken using the Bonferroni test. The intra- and inter-examiner ICC´s were calculated. Results: Intra- and inter-examiner reliability was high, both being ICC ? 0.99, with the best frequency on axis Z. Conclusions: The most reliable landmarks were: Nasion, Sella, Basion, left Porion, point A, anterior nasal spine, Pogonion, Gnathion, Menton, frontozygomatic sutures, first lower molars and upper and lower incisors. Those with less reliability were the supraorbitals, right zygion and posterior nasal spine. Key words:Cone Beam Computed Tomography, cephalometry, landmark, orthodontics, reliability. PMID:22322503

  19. Anatomic Total Shoulder System

    Medline Plus

    Full Text Available ... to mark the anatomic neck. You can see up here, this is where the anatomic neck starts. We're going to follow this all the ... put it is wherever the osteotomy surface winds up being parallel to ... that's where we're going to start off with glenoid exposure. So now we're ...

  20. Optimization of abdominal fat quantification on CT imaging through use of standardized anatomic space: A novel approach

    International Nuclear Information System (INIS)

    Purpose: The quantification of body fat plays an important role in the study of numerous diseases. It is common current practice to use the fat area at a single abdominal computed tomography (CT) slice as a marker of the body fat content in studying various disease processes. This paper sets out to answer three questions related to this issue which have not been addressed in the literature. At what single anatomic slice location do the areas of subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) estimated from the slice correlate maximally with the corresponding fat volume measures? How does one ensure that the slices used for correlation calculation from different subjects are at the same anatomic location? Are there combinations of multiple slices (not necessarily contiguous) whose area sum correlates better with volume than does single slice area with volume? Methods: The authors propose a novel strategy for mapping slice locations to a standardized anatomic space so that same anatomic slice locations are identified in different subjects. The authors then study the volume-to-area correlations and determine where they become maximal. To address the third issue, the authors carry out similar correlation studies by utilizing two and three slices for calculating area sum. Results: Based on 50 abdominal CT data sets, the proposed mapping achieves significantly improved consistency of anatomic localization compared to current practice. Maximum correlations are achieved at different anatomic locations for SAT and VAT which are both different from the L4-L5 junction commonly utilized currently for single slice area estimation as a marker. Conclusions: The maximum area-to-volume correlation achieved is quite high, suggesting that it may be reasonable to estimate body fat by measuring the area of fat from a single anatomic slice at the site of maximum correlation and use this as a marker. The site of maximum correlation is not at L4-L5 as commonly assumed, but is more superiorly located at T12-L1 for SAT and at L3-L4 for VAT. Furthermore, the optimal anatomic locations for SAT and VAT estimation are not the same, contrary to common assumption. The proposed standardized space mapping achieves high consistency of anatomic localization by accurately managing nonlinearities in the relationships among landmarks. Multiple slices achieve greater improvement in correlation for VAT than for SAT. The optimal locations in the case of multiple slices are not contiguous

  1. Optimization of abdominal fat quantification on CT imaging through use of standardized anatomic space: A novel approach

    Energy Technology Data Exchange (ETDEWEB)

    Tong, Yubing; Udupa, Jayaram K., E-mail: jay@mail.med.upenn.edu [Department of Radiology, Medical Image Processing Group, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6021 (United States); Torigian, Drew A. [Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6021 (United States)

    2014-06-15

    Purpose: The quantification of body fat plays an important role in the study of numerous diseases. It is common current practice to use the fat area at a single abdominal computed tomography (CT) slice as a marker of the body fat content in studying various disease processes. This paper sets out to answer three questions related to this issue which have not been addressed in the literature. At what single anatomic slice location do the areas of subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) estimated from the slice correlate maximally with the corresponding fat volume measures? How does one ensure that the slices used for correlation calculation from different subjects are at the same anatomic location? Are there combinations of multiple slices (not necessarily contiguous) whose area sum correlates better with volume than does single slice area with volume? Methods: The authors propose a novel strategy for mapping slice locations to a standardized anatomic space so that same anatomic slice locations are identified in different subjects. The authors then study the volume-to-area correlations and determine where they become maximal. To address the third issue, the authors carry out similar correlation studies by utilizing two and three slices for calculating area sum. Results: Based on 50 abdominal CT data sets, the proposed mapping achieves significantly improved consistency of anatomic localization compared to current practice. Maximum correlations are achieved at different anatomic locations for SAT and VAT which are both different from the L4-L5 junction commonly utilized currently for single slice area estimation as a marker. Conclusions: The maximum area-to-volume correlation achieved is quite high, suggesting that it may be reasonable to estimate body fat by measuring the area of fat from a single anatomic slice at the site of maximum correlation and use this as a marker. The site of maximum correlation is not at L4-L5 as commonly assumed, but is more superiorly located at T12-L1 for SAT and at L3-L4 for VAT. Furthermore, the optimal anatomic locations for SAT and VAT estimation are not the same, contrary to common assumption. The proposed standardized space mapping achieves high consistency of anatomic localization by accurately managing nonlinearities in the relationships among landmarks. Multiple slices achieve greater improvement in correlation for VAT than for SAT. The optimal locations in the case of multiple slices are not contiguous.

  2. An Efficient Ceiling-view SLAM Using Relational Constraints Between Landmarks

    Directory of Open Access Journals (Sweden)

    Hyukdoo Choi

    2014-01-01

    Full Text Available In this paper, we present a new indoor ‘simultaneous localization and mapping’ (SLAM technique based on an upward-looking ceiling camera. Adapted from our previous work [17], the proposed method employs sparsely-distributed line and point landmarks in an indoor environment to aid with data association and reduce extended Kalman filter computation as compared with earlier techniques. Further, the proposed method exploits geometric relationships between the two types of landmarks to provide added information about the environment. This geometric information is measured with an upward-looking ceiling camera and is used as a constraint in Kalman filtering. The performance of the proposed ceiling-view (CV SLAM is demonstrated through simulations and experiments. The proposed method performs localization and mapping more accurately than those methods that use the two types of landmarks without taking into account their relative geometries.

  3. Landmark experiments in twentieth-century physics

    CERN Document Server

    Trigg, George L

    2011-01-01

    Physics is very much an experimental science, but too often, students at the undergraduate level are not exposed to the reality of experimental physics ? i.e., what was done in a given experiment, why it was done, the background of physics against which the experiment was carried out and the changes in theory and knowledge that resulted. In this hook, the author helps to remedy the situation by presenting a variety of ""landmark"" experiments that have brought about significant alterations in our ideas about some aspect of nature. Among these scientific milestones are discoveries about the wa

  4. Algorithms to automatically quantify the geometric similarity of anatomical surfaces

    CERN Document Server

    Boyer, D; Clair, E St; Puente, J; Funkhouser, T; Patel, B; Jernvall, J; Daubechies, I

    2011-01-01

    We describe new approaches for distances between pairs of 2-dimensional surfaces (embedded in 3-dimensional space) that use local structures and global information contained in inter-structure geometric relationships. We present algorithms to automatically determine these distances as well as geometric correspondences. This is motivated by the aspiration of students of natural science to understand the continuity of form that unites the diversity of life. At present, scientists using physical traits to study evolutionary relationships among living and extinct animals analyze data extracted from carefully defined anatomical correspondence points (landmarks). Identifying and recording these landmarks is time consuming and can be done accurately only by trained morphologists. This renders these studies inaccessible to non-morphologists, and causes phenomics to lag behind genomics in elucidating evolutionary patterns. Unlike other algorithms presented for morphological correspondences our approach does not requir...

  5. UAV Control on the Basis of 3D Landmark Bearing-Only Observations.

    Science.gov (United States)

    Karpenko, Simon; Konovalenko, Ivan; Miller, Alexander; Miller, Boris; Nikolaev, Dmitry

    2015-01-01

    The article presents an approach to the control of a UAV on the basis of 3D landmark observations. The novelty of the work is the usage of the 3D RANSAC algorithm developed on the basis of the landmarks' position prediction with the aid of a modified Kalman-type filter. Modification of the filter based on the pseudo-measurements approach permits obtaining unbiased UAV position estimation with quadratic error characteristics. Modeling of UAV flight on the basis of the suggested algorithm shows good performance, even under significant external perturbations. PMID:26633394

  6. Detection of natural landmarks through multiscale opponent features

    OpenAIRE

    Todt, Eduardo; Torras Genís, Carme

    2000-01-01

    This work presents a landmark detection system for the walking robot operating in unknown unstructured outdoor environments. Most landmark detection approaches are not adequate for this application, since they rely on either structured information or a priori knowledge about the landmarks. Instead, the proposed system makes use of visual saliency concepts stemming from studies of animal and human perception. Thus, biologically inspired opponent features (in color and orientation) are searched...

  7. Using landmarks to support older people in navigation

    OpenAIRE

    Goodman, J.; Gray, P.D.G.; Khammampad, K.; Brewster, S.

    2004-01-01

    Although landmarks are an integral aspect of navigation, they have rarely been used within electronic navigation aids. This paper describes the design of a pedestrian navigation aid for a handheld computer, which guides the user along a route using photographs of landmarks, together with audio and text instructions that reference these landmarks. This aid was designed with older users in mind who often find their mobility hampered by declines in sensory, cognitive and motor abilities. It was ...

  8. Combining Path Integration and Remembered Landmarks When Navigating without Vision

    OpenAIRE

    Kalia, Amy A.; Schrater, Paul R.; Legge, Gordon E.

    2013-01-01

    This study investigated the interaction between remembered landmark and path integration strategies for estimating current location when walking in an environment without vision. We asked whether observers navigating without vision only rely on path integration information to judge their location, or whether remembered landmarks also influence judgments. Participants estimated their location in a hallway after viewing a target (remembered landmark cue) and then walking blindfolded to the same...

  9. Reconciling landmarks and level sets: geometric shape warping and matching using generalized gradients and correspondence-augmented implicit representations

    OpenAIRE

    Maurel, Pierre; Faugeras, Olivier; Keriven, Renaud

    2006-01-01

    Shape warping is a key problem in statistical shape analysis. This paper proposes a framework for geometric shape warping based on both shape distances and landmarks. Taking advantage of the recently proposed spatially coherent flows, our method is mathematically well-posed and uses only intrinsic shape information, namely some similarity measure between shapes and the correspondence of landmarks provided on the shape surface. No extrinsic quantity is considered, neither a diffeomorphism of t...

  10. Landmark vs. Geometry Learning: Explaining Female Rats' Selective Preference for a Landmark

    Science.gov (United States)

    Torres, Marta N.; Rodríguez, Clara A.; Chamizo, V. D.; Mackintosh, N. J.

    2014-01-01

    Rats were trained in a triangular-shaped pool to find a hidden platform, whose location was defined in terms of two sources of information, a landmark outside the pool and a particular corner of the pool. Subsequent test trials without the platform pitted these two sources of information against one another. In Experiment 1 this test revealed a…

  11. Comparison of Different Computer–Aided Surgery Systems in Skull Base Surgery

    OpenAIRE

    Ecke, U.; Luebben, B.; Maurer, J; Boor, S; Mann, W. J.

    2003-01-01

    Computer–aided surgery (CAS) based on high–resolution imaging techniques represents an important adjunct to precise intraoperative orientation when anatomical landmarks are distorted or missing. Several commercial systems, mostly based on optical or electromagnetic navigation principles, are on the market. This study investigated the application of EasyGuide®, VectorVision®, and InstaTrak® CAS systems in ENT surgery under practical and laboratory conditions. System accuracy, time required, ha...

  12. Anatomical Abnormalities in Autism?

    Science.gov (United States)

    Haar, Shlomi; Berman, Sigal; Behrmann, Marlene; Dinstein, Ilan

    2016-04-01

    Substantial controversy exists regarding the presence and significance of anatomical abnormalities in autism spectrum disorders (ASD). The release of the Autism Brain Imaging Data Exchange (∼1000 participants, age 6-65 years) offers an unprecedented opportunity to conduct large-scale comparisons of anatomical MRI scans across groups and to resolve many of the outstanding questions. Comprehensive univariate analyses using volumetric, thickness, and surface area measures of over 180 anatomically defined brain areas, revealed significantly larger ventricular volumes, smaller corpus callosum volume (central segment only), and several cortical areas with increased thickness in the ASD group. Previously reported anatomical abnormalities in ASD including larger intracranial volumes, smaller cerebellar volumes, and larger amygdala volumes were not substantiated by the current study. In addition, multivariate classification analyses yielded modest decoding accuracies of individuals' group identity (<60%), suggesting that the examined anatomical measures are of limited diagnostic utility for ASD. While anatomical abnormalities may be present in distinct subgroups of ASD individuals, the current findings show that many previously reported anatomical measures are likely to be of low clinical and scientific significance for understanding ASD neuropathology as a whole in individuals 6-35 years old. PMID:25316335

  13. Validation of anatomically shaped cranial collimation (ACC) in orthodontic lateral cephalography.

    Science.gov (United States)

    Hoogeveen, R C; Guicherit, P J; Gopie, S R; van der Stelt, P F; Berkhout, W E R

    2014-01-01

    The use of an anatomically shaped cranial collimator (ACC) to reduce patient dose in orthodontic lateral cephalography was investigated in this study. The aim was to evaluate the potential interference of the ACC on landmark identification for orthodontic cephalometry. Consecutive orthodontic patients underwent a total of 100 cephalograms using an ACC mounted on a Veraviewepocs(®) 3D X550 (J. Morita Co., Kyoto, Japan) X-ray unit. 10 observers were asked whether the identification of 5 landmarks close to the collimated area was hindered or rendered impossible by the presence of the collimator. Of the 500 landmarks that were judged by the 10 observers, 496 (99.2%) were reported to lack hindrance. In three landmarks, a minority of the observers reported hindrance. In 1 landmark, 8 of the 10 observers reported hindrance by the collimator. In no instance did the observers state that the identification of landmarks was impossible as a result of the collimation. Application of the ACC on the cephalostat of the X-ray unit is a viable way of reducing patient dose, as it only marginally interferes with the diagnostic yield of the exposure. The need to retake images when the ACC is applied was found to be extremely low. PMID:24720607

  14. Precision landmark location for machine vision and photogrammetry finding and achieving the maximum possible accuracy

    CERN Document Server

    Gutierrez, José A

    2007-01-01

    Shows the reader how to derive theoretical limits to the precision of landmark identification in electronic imagesMATLAB® package assists the reader with applying theoretical results in real engineering systemsSteps outside the usual earth-sciences and civil-engineering base of photogrammetry to improve animation, medical imaging and robotic vision applications

  15. FACIAL LANDMARKING LOCALIZATION FOR EMOTION RECOGNITION USING BAYESIAN SHAPE MODELS

    Directory of Open Access Journals (Sweden)

    Hernan F. Garcia

    2013-02-01

    Full Text Available This work presents a framework for emotion recognition, based in facial expression analysis using Bayesian Shape Models (BSM for facial landmarking localization. The Facial Action Coding System (FACS compliant facial feature tracking based on Bayesian Shape Model. The BSM estimate the parameters of the model with an implementation of the EM algorithm. We describe the characterization methodology from parametric model and evaluated the accuracy for feature detection and estimation of the parameters associated with facial expressions, analyzing its robustness in pose and local variations. Then, a methodology for emotion characterization is introduced to perform the recognition. The experimental results show that the proposed model can effectively detect the different facial expressions. Outperforming conventional approaches for emotion recognition obtaining high performance results in the estimation of emotion present in a determined subject. The model used and characterization methodology showed efficient to detect the emotion type in 95.6% of the cases.

  16. Trade-offs between leaf hydraulic capacity and drought vulnerability: morpho-anatomical bases, carbon costs and ecological consequences.

    Science.gov (United States)

    Nardini, Andrea; Pedà, Giulia; La Rocca, Nicoletta

    2012-11-01

    Leaf hydraulic conductance (K(leaf) ) and vulnerability constrain plant productivity, but no clear trade-off between these fundamental functional traits has emerged in previous studies. We measured K(leaf) on a leaf area (K(leaf_area)) and mass basis (K(leaf_mass)) in six woody angiosperms, and compared these values with species' distribution and leaf tolerance to dehydration in terms of P(50), that is, the leaf water potential inducing 50% loss of K(leaf) . We also measured several morphological and anatomical traits associated with carbon investment in leaf construction and water transport efficiency. Clear relationships emerged between K(leaf_mass), P(50), and leaf mass per unit area (LMA), suggesting that increased tolerance to hydraulic dysfunction implies increased carbon costs for leaf construction and water use. Low P(50) values were associated with narrower and denser vein conduits, increased thickness of conduit walls, and increased vein density. This, in turn, was associated with reduced leaf surface area. Leaf P(50) was closely associated with plants' distribution over a narrow geographical range, suggesting that this parameter contributes to shaping vegetation features. Our data also highlight the carbon costs likely to be associated with increased leaf tolerance to hydraulic dysfunction, which confers on some species the ability to thrive under reduced water availability but decreases their competitiveness in high-resource habitats. PMID:22978628

  17. Computer-aided diagnostic scheme for the detection of lung nodules on chest radiographs: Localized search method based on anatomical classification

    International Nuclear Information System (INIS)

    We developed an advanced computer-aided diagnostic (CAD) scheme for the detection of various types of lung nodules on chest radiographs intended for implementation in clinical situations. We used 924 digitized chest images (992 noncalcified nodules) which had a 500x500 matrix size with a 1024 gray scale. The images were divided randomly into two sets which were used for training and testing of the computerized scheme. In this scheme, the lung field was first segmented by use of a ribcage detection technique, and then a large search area (448x448 matrix size) within the chest image was automatically determined by taking into account the locations of a midline and a top edge of the segmented ribcage. In order to detect lung nodule candidates based on a localized search method, we divided the entire search area into 7x7 regions of interest (ROIs: 64x64 matrix size). In the next step, each ROI was classified anatomically into apical, peripheral, hilar, and diaphragm/heart regions by use of its image features. Identification of lung nodule candidates and extraction of image features were applied for each localized region (128x128 matrix size), each having its central part (64x64 matrix size) located at a position corresponding to a ROI that was classified anatomically in the previous step. Initial candidates were identified by use of the nodule-enhanced image obtained with the average radial-gradient filtering technique, in which the filter size was varied adaptively depending on the location and the anatomical classification of the ROI. We extracted 57 image features from the original and nodule-enhanced images based on geometric, gray-level, background structure, and edge-gradient features. In addition, 14 image features were obtained from the corresponding locations in the contralateral subtraction image. A total of 71 image features were employed for three sequential artificial neural networks (ANNs) in order to reduce the number of false-positive candidates. All parameters for ANNs, i.e., the number of iterations, slope of sigmoid functions, learning rate, and threshold values for removing the false positives, were determined automatically by use of a bootstrap technique with training cases. We employed four different combinations of training and test image data sets which was selected randomly from the 924 cases. By use of our localized search method based on anatomical classification, the average sensitivity was increased to 92.5% with 59.3 false positives per image at the level of initial detection for four different sets of test cases, whereas our previous technique achieved an 82.8% of sensitivity with 56.8 false positives per image. The computer performance in the final step obtained from four different data sets indicated that the average sensitivity in detecting lung nodules was 70.1% with 5.0 false positives per image for testing cases and 70.4% sensitivity with 4.2 false positives per image for training cases. The advanced CAD scheme involving the localized search method with anatomical classification provided improved detection of pulmonary nodules on chest radiographs for 924 lung nodule cases

  18. Anatomic Total Shoulder System

    Medline Plus

    Full Text Available ... a patient's unique anatomical makeup. Dr. Gerald R. Williams, Jr., a shoulder specialist from the Rothman Institute ... at Methodist Hospital in Philadelphia, where Dr. Jerry Williams will be performing a total shoulder arthroplasty. Before ...

  19. Anatomic Total Shoulder System

    Medline Plus

    Full Text Available GLOBAL AP ANATOMIC TOTAL SHOULDER SYSTEM METHODIST HOSPITAL PHILADELPHIA, PA April 17, 2008 00:00:10 ANNOUNCER: DePuy Orthopedics is continually advancing the standard of orthopedic patient ...

  20. Anatomic Total Shoulder System

    Science.gov (United States)

    ... not in the United States. They might in Europe, but they don't here. Patients who get ... Anatomic Total Shoulder surgery, which featured the latest innovation in shoulder surgery from DePuy Orthopedics. OR-Live ...

  1. Anatomic Total Shoulder System

    Medline Plus

    Full Text Available ... watch a live global AP anatomic total shoulder surgery from Methodist Hospital in Philadelphia. A revolution in ... m Jerry Williams. I'll be performing the surgery today, and we have lots of help. We ...

  2. Anatomic Total Shoulder System

    Medline Plus

    Full Text Available ... moments, you'll be able to watch a live global AP anatomic total shoulder surgery from Methodist ... specialist, Dr. Douglas Boardman III will moderate. OR-Live makes it easy for you to learn more. ...

  3. Anatomic Total Shoulder System

    Medline Plus

    Full Text Available ... to a patient's unique anatomical makeup. Dr. Gerald R. Williams, Jr., a shoulder specialist from the Rothman ... That might help. Could you raise the O.R. table, please? 00:28:35 WOMAN: Can you ...

  4. Detailed Anatomical Orientations for Certain Types of Morphometric Measurements Can Be Determined Automatically With Geometric Algorithms.

    Science.gov (United States)

    Boyer, Doug M; Winchester, Julia M; Glynn, Chris; Puente, Jesus

    2015-11-01

    Morphometric datasets only convey useful information about variation when measurement landmarks and relevant anatomical axes are clearly defined. We propose that anatomical axes of 3D digital models of bones can be standardized prior to measurement using an algorithm that automatically finds a universal geometric alignment among sampled bones. As a case study, we use teeth of "prosimian" primates. In this sample, equivalent occlusal planes are determined automatically using the R-package auto3dgm. The area of projection into the occlusal plane for each tooth is the measurement of interest. This area is used in computation of a shape metric called relief index (RFI), the natural log of the square root of crown area divided by the square root of occlusal plane projection area. We compare mean and variance parameters of area and RFI values computed from these automatically orientated tooth models with values computed from manually orientated tooth models. According to our results, the manual and automated approaches yield extremely similar mean and variance parameters. The only differences that plausibly modify interpretations of biological meaning slightly favor the automated treatment because a greater proportion of differences among subsamples in the automated treatment are correlated with dietary differences. We conclude that-at least for dental topographic metrics-automated alignment recovers a variance pattern that has meaning similar to previously published datasets based on manual data collection. Therefore, future applications of dental topography can take advantage of automatic alignment to increase objectivity and repeatability. PMID:26228692

  5. Comparison of Intraoperative Portable CT Scanners in Skull Base and Endoscopic Sinus Surgery: Single Center Case Series

    OpenAIRE

    Conley, David B.; Tan, Bruce; Bendok, Bernard R; Batjer, H. Hunt; Chandra, Rakesh; Sidle, Douglas; Rahme, Rudy J.; Adel, Joseph G.; Fishman, Andrew J.

    2011-01-01

    Precise and safe management of complex skull base lesions can be enhanced by intraoperative computed tomography (CT) scanning. Surgery in these areas requires real-time feedback of anatomic landmarks. Several portable CT scanners are currently available. We present a comparison of our clinical experience with three portable scanners in skull base and craniofacial surgery. We present clinical case series and the participants were from the Northwestern Memorial Hospital. Three scanners are stud...

  6. 32 CFR 644.317 - Preserving historic landmarks and properties.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 4 2010-07-01 2010-07-01 true Preserving historic landmarks and properties. 644.317 Section 644.317 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) REAL PROPERTY REAL ESTATE HANDBOOK Disposal § 644.317 Preserving historic landmarks...

  7. 36 CFR 65.5 - Designation of National Historic Landmarks.

    Science.gov (United States)

    2010-07-01

    ... criteria but which do meet the National Register criteria for evaluation in 36 CFR part 60 or determine... Historic Landmarks. 65.5 Section 65.5 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL HISTORIC LANDMARKS PROGRAM § 65.5 Designation of National Historic...

  8. Visual motion-sensitive neurons in the bumblebee brain convey information about landmarks during a navigational task

    Directory of Open Access Journals (Sweden)

    Martin Egelhaaf

    2014-09-01

    Full Text Available Bees use visual memories to find the spatial location of previously learnt food sites. Characteristic learning flights help acquiring these memories at newly discovered foraging locations where landmarks - salient objects in the vicinity of the goal location - can play an important role in guiding the animal’s homing behavior. Although behavioral experiments have shown that bees can use a variety of visual cues to distinguish objects as landmarks, the question of how landmark features are encoded by the visual system is still open. Recently, it could be shown that motion cues are sufficient to allow bees localizing their goal using landmarks that can hardly be discriminated from the background texture. Here, we tested the hypothesis that motion sensitive neurons in the bee’s visual pathway provide information about such landmarks during a learning flight and might, thus, play a role for goal localization. We tracked learning flights of free-flying bumblebees (Bombus terrestris in an arena with distinct visual landmarks, reconstructed the visual input during these flights, and replayed ego-perspective movies to tethered bumblebees while recording the activity of direction-selective wide-field neurons in their optic lobe. By comparing neuronal responses during a typical learning flight and targeted modifications of landmark properties in this movie we demonstrate that these objects are indeed represented in the bee’s visual motion pathway. We find that object-induced responses vary little with object texture, which is in agreement with behavioral evidence. These neurons thus convey information about landmark properties that are useful for view-based homing.

  9. Tracking in anatomic pathology.

    Science.gov (United States)

    Pantanowitz, Liron; Mackinnon, Alexander C; Sinard, John H

    2013-12-01

    Bar code-based tracking solutions, long present in clinical pathology laboratories, have recently made an appearance in anatomic pathology (AP) laboratories. Tracking of AP "assets" (specimens, blocks, slides) can enhance laboratory efficiency, promote patient safety, and improve patient care. Routing of excess clinical material into research laboratories and biorepositories are other avenues that can benefit from tracking of AP assets. Implementing tracking is not as simple as installing software and turning it on. Not all tracking solutions are alike. Careful analysis of laboratory workflow is needed before implementing tracking to assure that this solution will meet the needs of the laboratory. Such analysis will likely uncover practices that may need to be modified before a tracking system can be deployed. Costs that go beyond simply that of purchasing software will be incurred and need to be considered in the budgeting process. Finally, people, not technology, are the key to assuring quality. Tracking will require significant changes in workflow and an overall change in the culture of the laboratory. Preparation, training, buy-in, and accountability of the people involved are crucial to the success of this process. This article reviews the benefits, available technology, underlying principles, and implementation of tracking solutions for the AP and research laboratory. PMID:23634908

  10. Elections and landmark policies in Tanzania and Uganda

    DEFF Research Database (Denmark)

    Kjær, Anne Mette; Therkildsen, Ole

    2013-01-01

    Much of the relevant literature on Africa downplays the salience of elections for policy-making and implementation. Instead, the importance of factors such as clientelism, ethnicity, organized interest group and donor influence, is emphasized. We argue that, in addition, elections now motivate political elites to focus on policies they perceive to be able to gain votes. This is based on analyses of six landmark decisions made during the last fifteen years in the social, productive and public finance sectors in Tanzania and Uganda. Such policies share a number of key characteristics: they are clearly identifiable with the party in power; citizens country-wide are targeted; and policy implementation aim at immediate, visible results. The influence of elections on policy making and implementation could therefore be more significant in countries where elections are more competitive than in Tanzania and Uganda.

  11. 75 FR 49520 - Landmarks Committee of the National Park System Advisory Board Meeting

    Science.gov (United States)

    2010-08-13

    ...of the Landmarks Committee are: Mr. Ronald...Historic Landmarks nominations, amendments to...and its Landmarks Committee may consider the following nominations: Nominations Delaware...HISTORIC DISTRICT, Independence, MO...

  12. Plantar calcaneal enthesophytes: new observations regarding sites of origin based on radiographic, MR imaging, anatomic, and paleopathologic analysis

    International Nuclear Information System (INIS)

    To determine the relationship between sites of calcaneal plantar enthesophytes and surrounding fascial and soft tissue structures using routine radiography, MR imaging, and data derived from cadaveric and paleopathologic specimens.Design and patients. Two observers analyzed the MR imaging studies of 40 ankles in 38 patients (35 males, 3 females; mean age 48.3 years) with plantar calcaneal enthesophytes that were selected from all the ankle MR examinations performed during the past year. Data derived from these MR examinations were the following: the size of the enthesophyte; its location in relation to the plantar fascia (PF) and flexor muscles; and the thickness and signal of the PF. The corresponding radiographs of the ankles were evaluated at a different time by the same observers for the presence or absence of plantar enthesophytes and, when present, their measurements. A third observer reviewed all the discordant observations of MR imaging and radiographic examinations. Two observers analyzed 22 calcaneal specimens with plantar enthesophytes at an anthropology museum to determine the orientation of each plantar enthesophyte. MR imaging of a cadaveric foot with a plantar enthesophyte with subsequent sagittal sectioning was performed to provide further anatomic understanding.Results. With regard to MR imaging, the mean size of the plantar enthesophytes was 4.41 mm (SD 2.4). Twenty (50%) enthesophytes were located above the PF, 16 (40%) between the fascia and abductor digiti minimi, flexor digitorum brevis and abductor hallucis muscles, and only one (3%) was located within the PF. In three (8%) cases the location was not determined. The size of enthesophytes seen with MR imaging and radiographs was highly correlated (P0.8, kappa >0.9). Eleven of the 22 bone specimens had plantar enthesophytes oriented in the direction of the abductor digiti minimi and 11 oriented in the direction of the flexor digitorum brevis and PF. The cadaveric sections revealed different types of enthesophytes.Conclusions. Plantar calcaneal enthesophytes arise in five different locations: at the insertion sites of abductor digiti minimi and flexor digitorum brevis muscles; between the PF and these muscles; and, less frequently, within the PF and at the insertion site of the short plantar ligament. (orig.)

  13. The location of midfacial landmarks according to the method of establishing the midsagittal reference plane in three-dimensional computed tomography analysis of facial asymmetry

    Science.gov (United States)

    Kim, Min Sun; Lee, Eun Joo; Song, In Ja; Lee, Jae-Seo; Kang, Byung-Cheol

    2015-01-01

    Purpose The purpose of this study was to evaluate the influence of methods of establishing the midsagittal reference plane (MRP) on the locations of midfacial landmarks in the three-dimensional computed tomography (CT) analysis of facial asymmetry. Materials and Methods A total of 24 patients (12 male and 12 female; mean age, 22.5 years; age range, 18.2-29.7 years) with facial asymmetry were included in this study. The MRP was established using two different methods on each patient's CT image. The x-coordinates of four midfacial landmarks (the menton, nasion, upper incisor, and lower incisor) were obtained by measuring the distance and direction of the landmarks from the MRP, and the two methods were compared statistically. The direction of deviation and the severity of asymmetry found using each method were also compared. Results The x-coordinates of the four anatomic landmarks all showed a statistically significant difference between the two methods of establishing the MRP. For the nasion and lower incisor, six patients (25.0%) showed a change in the direction of deviation. The severity of asymmetry also changed in 16 patients (66.7%). Conclusion The results of this study suggest that the locations of midfacial landmarks change significantly according to the method used to establish the MRP. PMID:26730370

  14. An anatomically oriented breast model for MRI

    Science.gov (United States)

    Kutra, Dominik; Bergtholdt, Martin; Sabczynski, Jörg; Dössel, Olaf; Buelow, Thomas

    2015-03-01

    Breast cancer is the most common cancer in women in the western world. In the breast cancer care-cycle, MRIis e.g. employed in lesion characterization and therapy assessment. Reading of a single three dimensional image or comparing a multitude of such images in a time series is a time consuming task. Radiological reporting is done manually by translating the spatial position of a finding in an image to a generic representation in the form of a breast diagram, outlining quadrants or clock positions. Currently, registration algorithms are employed to aid with the reading and interpretation of longitudinal studies by providing positional correspondence. To aid with the reporting of findings, knowledge about the breast anatomy has to be introduced to translate from patient specific positions to a generic representation. In our approach we fit a geometric primitive, the semi-super-ellipsoid to patient data. Anatomical knowledge is incorporated by fixing the tip of the super-ellipsoid to the mammilla position and constraining its center-point to a reference plane defined by landmarks on the sternum. A coordinate system is then constructed by linearly scaling the fitted super-ellipsoid, defining a unique set of parameters to each point in the image volume. By fitting such a coordinate system to a different image of the same patient, positional correspondence can be generated. We have validated our method on eight pairs of baseline and follow-up scans (16 breasts) that were acquired for the assessment of neo-adjuvant chemotherapy. On average, the location predicted and the actual location of manually set landmarks are within a distance of 5.6 mm. Our proposed method allows for automatic reporting simply by uniformly dividing the super-ellipsoid around its main axis.

  15. Model-based automatic detection of the anterior and posterior commissures on MRI scans.

    Science.gov (United States)

    Ardekani, Babak A; Bachman, Alvin H

    2009-07-01

    The projections of the anterior and posterior commissures (AC/PC) on the mid-sagittal plane of the human brain are important landmarks in neuroimaging. They can be used, for example, during MRI scanning for acquiring the imaging sections in a standard orientation. In post-acquisition image processing, these landmarks serve to establish an anatomically-based frame of reference within the brain that can be extremely useful in designing automated image analysis algorithms such as image segmentation and registration methods. This paper presents a fully automatic model-based algorithm for AC/PC detection on MRI scans. The algorithm utilizes information from a number of model images on which the locations of the AC/PC and a reference point (the vertex of the superior pontine sulcus) are known. This information is then used to locate the landmarks on test scans by template matching. The algorithm is designed to be fast, robust, and accurate. The method is flexible in that it can be trained to work on different image contrasts, optimized for different populations, or scanning modes. To assess the effectiveness of this technique, we compared automatically and manually detected landmark locations on 84 T(1)-weighted and 42 T(2)-weighted test scans. Overall, the average Euclidean distance between automatically and manually detected landmarks was 1.1 mm. A software implementation of the algorithm is freely available online at www.nitrc.org/projects/art. PMID:19264138

  16. Dose reduction in computed tomography by attenuation-based on-line modulation of tube current: evaluation of six anatomical regions

    Energy Technology Data Exchange (ETDEWEB)

    Greess, H.; Baum, U.; Lell, M.; Bautz, W.A. [Inst. of Diagnostic Radiology, Univ. of Erlangen (Germany); Wolf, H.; Kalender, W. [Inst. of Medical Physics, Univ. of Erlangen (Germany); Pirkl, M. [Inst. of Radiation Therapy, Univ. of Erlangen (Germany)

    2000-02-01

    This study investigated the potential of attenuation-based on-line modulation of tube current to reduce the dose of computed tomography (in milliamperes) without loss in image quality. The dose can be reduced for non-circular patient cross-sections by reducing the tube current at the angular positions at which the diameter through the patient diameter is smallest. We investigated a new technical approach with attenuation-based on-line modulation of tube current. Computed tomographic projection data were analyzed to determine the optimal milliampere values for each projection angle in real time, instead of performing prior measurements with localizer radiographs. We compared image quality, noise pattern, and dose for standard scans and for scans with attenuation-based on-line modulation of tube current in a group of 30 radiation therapy patients. Six different anatomical regions were examined: head, shoulder, thorax, abdomen, pelvis, and extremities (knee). Image quality was evaluated by four radiologists in a blinded fashion. We found the dose to be reduced typically by 15-50 %. In general, no deterioration in image quality was observed. Thus the dose in computed tomography be reduced substantially by technical measures without sacrificing image quality. Attenuation-based on-line modulation of tube current is an efficient and practical means for this. (orig.)

  17. Anatomic Total Shoulder System

    Medline Plus

    Full Text Available ... for restoration of version anatomically here? 00:37:25 GERALD WILLIAMS, MD: I use my three-dimensional study from preoperatively ... I'd like to thank everybody. 01:20:25 N. DOUGLAS BOARDMAN III, MD: So I think right now with things completed, ...

  18. Anatomic Total Shoulder System

    Medline Plus

    Full Text Available ... advancing the standard of orthopedic patient care. In a few moments, you'll be able to watch a live global AP anatomic total shoulder surgery from Methodist Hospital in Philadelphia. A revolution in shoulder orthopedics, the Global AP gives ...

  19. Anatomic Total Shoulder System

    Medline Plus

    Full Text Available ... we'll put in an anatomic Global AP stem on the humeral side. And if you'll ... So we're going to use a 14 stem, a 52x21 head with a ball taper offset. ... position of the taper with respect to the stem. So then we take this off. We take ...

  20. Pedro Ara anatomic museum.

    Science.gov (United States)

    Montenegro, V A; Trefilio, D E; Borghino, V N; Páez, R E; Aranega, C I

    2006-03-01

    Museums where anatomical pieces are exhibited are disappearing. The advance of the computer together with the advance of conventional and three-dimensional radiology makes the organs to be exposed without practicing dissection and the virtual images replace the real ones in the educational process. Some current laws that restrict the use of corpses and fetuses for obituary and exhibition studies have also contributed to the tendency. The anatomical museum, today named Pedro Ara, was founded in December 1920 and it exhibits anatomic works from the embryonic stage to old age, contributing unbeatable teachings to the medical sciences and the general public. The museum is located in the Angel Roque Suarez Anatomic Institute in the Clinical National Hospital which depends on the National University of Cordoba. It is visited daily by hundreds of people from all over the world. The museum owns 1211 pieces that combine ethical, scientific, aesthetical and educational values achieving a realization that received international acknowledgement. The most valuable exhibited work is 'Old man's head' made by Professor Pedro Ara in 1928-1929 (Figure 1), which, owing to its high quality, is in an impeccable and unharmed condition despite being exhibited for 80 years. Other authors, such as Professor Humberto Fracassi, also enriched the museum with their work and we, convinced that it favors and will favor our human formation and professional training, have the privilege of being their heirs and the responsibility of being their followers. PMID:16551427

  1. Anatomic Total Shoulder System

    Medline Plus

    Full Text Available ... Anatomic Total Shoulder surgery, which featured the latest innovation in shoulder surgery from DePuy Orthopedics. OR-Live makes it easy for you to learn more. Just click on the "Request Information" button on your webcast screen and open the door to informed medical care. 01:21: ...

  2. Anatomic Total Shoulder System

    Medline Plus

    Full Text Available ... not in the United States. They might in Europe, but they don't here. Patients who get ... Anatomic Total Shoulder surgery, which featured the latest innovation in shoulder surgery from DePuy Orthopedics. OR-Live ...

  3. Anatomic Total Shoulder System

    Medline Plus

    Full Text Available ... by almost ten years, is shoulders. So by definition, the average shoulder-replacement patient is almost ten ... Anatomic Total Shoulder surgery, which featured the latest innovation in shoulder surgery from DePuy Orthopedics. OR-Live ...

  4. Some historical landmarks in nuclear and radiochemistry

    International Nuclear Information System (INIS)

    The study of conduction of electricity through evacuated tubes led to the discovery of cathode rays by Plucker in 1858. No outstanding results were produced in the study of these rays until 1895-1896 when incisive minds of Roentgen and Thomson led, respectively, to the Nobel prize winning discoveries of x-rays and electron. Fortutious linking of phosphorescence with x-ray emission led Becquerel to discover uranic rays and his colleagues M. Curie an P. Curie to their research on radiation phenomenon. A gigantic forward wave of human knowledge ensued from these discoveries. The postulation of nuclear atom by Rutherford was an important landmark in this forward movement. Rutherford and Soddy postulated that the spontaneous emission of radiations (? and ?) by atoms is accompanied by chemical changes. Subsequent studies by Rutherford and his colleagues in England, Curie-Joliot team in France, Fermi et al. in Italy and Hahn et al. in Germany established transmutation of atomic nuclei by nuclear radiations (? and n). This article is an attempt to pay a humble tribute to the pioneers who opened the gates to the world of nuclear sciences. (author). 135 refs., 1 fig

  5. Diffeomorphic Anatomical Registration Through Exponentiated Lie Algebra provides reduced effect of scanner for cortex volumetry with atlas-based method in healthy subjects

    Energy Technology Data Exchange (ETDEWEB)

    Goto, Masami; Ino, Kenji; Yano, Keiichi [University of Tokyo Hospital, Department of Radiological Technology, Bunkyo-ku, Tokyo (Japan); Abe, Osamu [Nihon University School of Medicine, Department of Radiology, Itabashi-ku, Tokyo (Japan); Aoki, Shigeki [Juntendo University, Department of Radiology, Bunkyo-ku, Tokyo (Japan); Hayashi, Naoto [University of Tokyo Hospital, Department of Computational Diagnostic Radiology and Preventive Medicine, Bunkyo-ku, Tokyo (Japan); Miyati, Tosiaki [Kanazawa University, Graduate School of Medical Science, Kanazawa (Japan); Takao, Hidemasa; Mori, Harushi; Kunimatsu, Akira; Ohtomo, Kuni [University of Tokyo Hospital, Department of Radiology and Department of Computational Diagnostic Radiology and Preventive Medicine, Bunkyo-ku, Tokyo (Japan); Iwatsubo, Takeshi [University of Tokyo, Department of Neuropathology, Bunkyo-ku, Tokyo (Japan); Yamashita, Fumio [Iwate Medical University, Department of Radiology, Yahaba, Iwate (Japan); Matsuda, Hiroshi [Integrative Brain Imaging Center National Center of Neurology and Psychiatry, Department of Nuclear Medicine, Kodaira, Tokyo (Japan); Collaboration: Japanese Alzheimer' s Disease Neuroimaging Initiative

    2013-07-15

    This study aimed to investigate whether the effect of scanner for cortex volumetry with atlas-based method is reduced using Diffeomorphic Anatomical Registration Through Exponentiated Lie Algebra (DARTEL) normalization compared with standard normalization. Three-dimensional T1-weighted magnetic resonance images (3D-T1WIs) of 21 healthy subjects were obtained and evaluated for effect of scanner in cortex volumetry. 3D-T1WIs of the 21 subjects were obtained with five MRI systems. Imaging of each subject was performed on each of five different MRI scanners. We used the Voxel-Based Morphometry 8 tool implemented in Statistical Parametric Mapping 8 and WFU PickAtlas software (Talairach brain atlas theory). The following software default settings were used as bilateral region-of-interest labels: ''Frontal Lobe,'' ''Hippocampus,'' ''Occipital Lobe,'' ''Orbital Gyrus,'' ''Parietal Lobe,'' ''Putamen,'' and ''Temporal Lobe.'' Effect of scanner for cortex volumetry using the atlas-based method was reduced with DARTEL normalization compared with standard normalization in Frontal Lobe, Occipital Lobe, Orbital Gyrus, Putamen, and Temporal Lobe; was the same in Hippocampus and Parietal Lobe; and showed no increase with DARTEL normalization for any region of interest (ROI). DARTEL normalization reduces the effect of scanner, which is a major problem in multicenter studies. (orig.)

  6. Route and landmark selection tool (RULST) : user's manual.; TOPICAL

    International Nuclear Information System (INIS)

    The Route and Landmark Selection Tool (RULST) is a software program designed to assist military planners in defining geographical objects, such as routes, landmarks, spurs, and yards, at a given facility. Argonne National Laboratory is currently developing a prototype of this tool for use by the Military Traffic Management Command Transportation Engineering Agency (MTMCTEA). The primary objective of RULST is to populate database tables of facility objects for use in MTMCTEA models. RULST defines facility data for use in models such as Port Simulation (PORTSIM) and Transportation System Capability (TRANSCAP), which simulate the transportation of equipment through ports and military installations. The main purpose of RULST is to allow you to specify the relationships between landmarks and routes. The nodes, links, and landmarks that describe a facility are often predefined on the basis of the layout of the physical site

  7. Anatomical variations in the aortic bifurcation in new zealand white rabbits on arteriography.

    Science.gov (United States)

    Balastegui, Maria Teresa; Ramos-Plá, Juan José; Ferrer-Puchol, Maria Dolores; Carrillo, Jose Maria; Monteagudo-Franco, Sergio Pedro; Esteban, Enrique; Liste, Fernando

    2014-04-01

    The radiologic anatomy of the aortic bifurcation in the rabbit has received little study but it is important as this anatomical area is widely used in atherosclerosis research. Thirty rabbits were used to study the aortic bifurcation and subsequent branching patterns on arteriography. Fifteen different arteries were identified. Mean arterial diameters of 2.88 ± 0.7 and 2.27 ± 0.55 mm were obtained for the aorta and external iliac arteries, respectively. The cranial and middle aspects at the seventh lumbar vertebra (L7) were the most frequent anatomical landmarks (53.3% of the cases) for aortic and common iliac bifurcations, respectively. The caudal aspect of L6 was the most frequent origin (50% of the cases) for the median sacral artery. Deep circumflex iliac arteries originated from common iliac arteries and not the abdominal aorta in the rabbit, showing anatomical asymmetry in 73.3% of the cases. No gender disparity was found in the anatomical location of any of the arteries of the study. Knowledge of normal vascular landmarks for the aortic bifurcation as well as anatomical variations should be helpful to future experimental studies. PMID:24478216

  8. Landmarking the Brain for Geometric Morphometric Analysis: An Error Study

    OpenAIRE

    Chollet, Madeleine B.; ALDRIDGE, KRISTINA; Pangborn, Nicole; Weinberg, Seth M; DeLeon, Valerie B.

    2014-01-01

    Neuroanatomic phenotypes are often assessed using volumetric analysis. Although powerful and versatile, this approach is limited in that it is unable to quantify changes in shape, to describe how regions are interrelated, or to determine whether changes in size are global or local. Statistical shape analysis using coordinate data from biologically relevant landmarks is the preferred method for testing these aspects of phenotype. To date, approximately fifty landmarks have been used to study b...

  9. A Novel Hybrid Approach for Cephalometric Landmark Detection

    OpenAIRE

    Majd, Mahshid; Shoeleh, Farzaneh

    2015-01-01

    Cephalometric analysis has an important role in dentistry and especially in orthodontics as a treatment planning tool to gauge the size and special relationships of the teeth, jaws and cranium. The first step of using such analyses is localizing some important landmarks known as cephalometric landmarks on craniofacial in x-ray image. The past decade has seen a growing interest in automating this process. In this paper, a novel hybrid approach is proposed for automatic detect...

  10. Potentiation and overshadowing between landmarks and environmental geometric cues

    OpenAIRE

    Horne, Murray R; PEARCE, JOHN M.

    2011-01-01

    Rats were required in three experiments to find one of two submerged platforms that were situated in diagonally opposite corners of a rectangular, grey swimming pool. The same corners were used throughout each experiment. Experimental groups were trained with landmarks, comprising A4 cards attached to the walls, located in the corners containing the platforms. For the control groups, the landmarks were situated in the corners containing the platforms for half the trials, and in the other corn...

  11. An Anatomically Oriented Breast Coordinate System for Mammogram Analysis

    DEFF Research Database (Denmark)

    Brandt, Sami; Karemore, Gopal Raghunath

    2011-01-01

    We have developed a breast coordinate system that is based on breast anatomy to register female breasts into a common coordinate frame in 2D mediolateral (ML) or mediolateral oblique (MLO) view mammograms. The breasts are registered according to the location of the pectoral muscle and the nipple and the shape of the breast boundary because these are the most robust features independent of the breast size and shape. On the basis of these landmarks, we have constructed a nonlinear mapping between the parameter frame and the breast region in the mammogram. This mapping makes it possible to identify the corresponding positions and orientations among all of the ML or MLO mammograms, which facilitates an implicit use of the registration, i.e., no explicit image warping is needed. We additionally show how the coordinate transform can be used to extract Gaussian derivative features so that the feature positions and orientations are registered and extracted without non-linearly deforming the images. We use the proposed breast coordinate transform in a cross-sectional breast cancer risk assessment study of 490 women, in which we attempt to learn breast cancer risk factors from mammograms that were taken prior to when the breast cancer became visible to a radiologist. The coordinate system provides both the relative position and orientation information on the breast region from which the features are derived. In addition, the coordinate system can be used in temporal studies to pin-point anatomically equivalent locations between the mammograms of each woman and among the mammograms of all of the women in the study. The results of the cross-sectional study show that the classification into cancer and control groups can be improved by using the new coordinate system, compared to other systems evaluated. Comparisons were performed using the area-under-the-receiveroperating- characteristic-curve (AUC) score. In general, the new coordinate system makes an accurate anatomical registration of breasts possible, which suggests its wide applicability wherever 2D mammogram registration is required.

  12. Design, construction and mechanical testing of digital 3D anatomical data-based PCL-HA bone tissue engineering scaffold.

    Science.gov (United States)

    Yao, Qingqiang; Wei, Bo; Guo, Yang; Jin, Chengzhe; Du, Xiaotao; Yan, Chao; Yan, Junwei; Hu, Wenhao; Xu, Yan; Zhou, Zhi; Wang, Yijin; Wang, Liming

    2015-01-01

    The study aims to investigate the techniques of design and construction of CT 3D reconstructional data-based polycaprolactone (PCL)-hydroxyapatite (HA) scaffold. Femoral and lumbar spinal specimens of eight male New Zealand white rabbits were performed CT and laser scanning data-based 3D printing scaffold processing using PCL-HA powder. Each group was performed eight scaffolds. The CAD-based 3D printed porous cylindrical stents were 16 piece × 3 groups, including the orthogonal scaffold, the Pozi-hole scaffold and the triangular hole scaffold. The gross forms, fiber scaffold diameters and porosities of the scaffolds were measured, and the mechanical testing was performed towards eight pieces of the three kinds of cylindrical scaffolds, respectively. The loading force, deformation, maximum-affordable pressure and deformation value were recorded. The pore-connection rate of each scaffold was 100 % within each group, there was no significant difference in the gross parameters and micro-structural parameters of each scaffold when compared with the design values (P > 0.05). There was no significant difference in the loading force, deformation and deformation value under the maximum-affordable pressure of the three different cylinder scaffolds when the load was above 320 N. The combination of CT and CAD reverse technology could accomplish the design and manufacturing of complex bone tissue engineering scaffolds, with no significant difference in the impacts of the microstructures towards the physical properties of different porous scaffolds under large load. PMID:25596860

  13. Landmarks of History of Soil Science in Sri Lanka

    Science.gov (United States)

    Mapa, R.

    2012-04-01

    Sri Lanka is a tropical Island in the Southern tip of Indian subcontinent positioned at 50 55' to 90 50' N latitude and 790 42' to 810 53' E longitude surrounded by the Indian Ocean. It is an island 435 km in length and 224 km width consisting of a land are of 6.56 million ha with a population of 20 million. In area wise it is ranked as 118th in the world, where at present ranked as 47 in population wise and ranked 19th in population density. The country was under colonial rule under Portuguese, Dutch and British from 1505 to 1948. The majority of the people in the past and present earn their living from activities based on land, which indicates the important of the soil resource. The objective of this paper is to describe the landmarks of the history of Soil Science to highlight the achievements and failures, which is useful to enrich our present understanding of Sri Lankan soils. The landmarks of the history of Soil Science in Sri Lanka can be divided to three phases namely, the early period (prior to 1956), the middle period (1956 to 1972) and the present period (from 1972 onwards). During the early period, detailed analytical studies of coffee and tea soils were compiled, and these gave mainly information on up-country soils which led to fertilizer recommendations based on field trials. In addition, rice and forest soils were also studied in less detail. The first classification of Sri Lankan soils and a provisional soil map based on parent material was published by Joachim in 1945 which is a major landmark of history of Soil Science in Sri Lanka. In 1959 Ponnamperuma proposed a soil classification system for wetland rice soils. From 1963 to 1968 valuable information on the land resource was collected and documented by aerial resource surveys funded by Canada-Ceylon Colombo plan aid project. This covered 18 major river basins and about 1/4th of Sri Lanka, which resulted in producing excellent soil maps and information of the areas called the Kelani Aruvi Ara and Walawe basins. The provisional soil map was updated by many other workers as Moorman and Panabokke in 1961 and 1972 using this information. The soil map produced by De Alwis and Panabokke in 1972 at a scale of 1:500,000 was the soil maps mostly used during the past years During the present era, the need for classification of Soils of Sri Lanka according to international methods was felt. A major leap forward in Soil Survey, Classification leading to development of a soil data base was initiated in 1995 with the commencement of the "SRICANSOL" project which was a twining project between the Soil Science Societies of Sri Lanka and Canada. This project is now completed with detail soil maps at a scale of 1:250,000 and soil classified according to international methods for the Wet, Intermediate and Dry zones of Sri Lanka. A digital database consisting of soil profile description and physical and chemical data is under preparation for 28, 40 and 51 benchmark sites of the Wet, Intermediate and Dry zones respectively. The emphases on studies on Soil Science in the country at present is more towards environmental conservation related to soil erosion control, reducing of pollution of soil and water bodies from nitrates, pesticide residues and heavy metal accumulation. Key words: Sri Lanka, Provisional soil map

  14. Manejo actual de la microtia: redefinición anátomo-quirúrgica Management of microtia based on a redefinition of its anatomical-surgical classification

    Directory of Open Access Journals (Sweden)

    Juan Pablo Sorolla P

    2012-12-01

    Full Text Available Objetivos: Reportar y evaluar la efectividad de una técnica quirúrgica, previamente descrita para el tratamiento de microtias, basado en un nuevo concepto de clasificación anátomo-quirúrgica. Material y Método: Estudio retrospectivo de pacientes tratados en el Hospital Militar y Clínica Alemana de Santiago en el Servicio de Cirugía Plástica desde enero de 2008 hasta diciembre de 2010. Se reclutaron a un total de 15 pacientes, 13 (87% de los cuales eran unilaterales y 2 (13% bilaterales. A todos los pacientes se les realizó la reconstrucción mediante técnica quirúrgica de Firmin. Resultados: Se operó a 15 pacientes de rango de edad entre 9 y 25 años, con una mediana de 11 años. De los casos unilaterales; 7 correspondían a tipo I de Firmin, 5 casos a tipo II Firmin y un caso tipo IIIa. De los casos bilaterales, ambos tenían microtia tipo IIIb. Se logró en la totalidad de los casos unilaterales una buena proyección inicial del marco cartilaginoso durante el primer tiempo quirúrgico. Seis casos fueron sometidos a un segundo tiempo quirúrgico. Durante el seguimiento mínimo de 18 meses, se observaron complicaciones en 4 (16% pacientes. Conclusiones: Se comprueba que mediante una técnica basada en la clasificación anátomo-quirúrgica, los resultados a corto plazo fueron favorables y satisfactorios.Background: Incomplete development and growth of the pinna can lead to a small or deformed pinna, called microtia. Aim: To report and evaluate the effectiveness of a surgical technique previously described for the treatment of microtia, based on a new anatomical-surgical classification. Materials and Methods: Retrospective study of patients treated at two plastic surgery departments from January 2008 to December 2010. We recruited a total of 15 patients aged 9 to 25 years. Thirteen (87% had unilateral and 2 (13% bilateral microtia. All patients underwent the surgical reconstructive technique described by Firmin. Results: Among patients with unilateral microtia, seven belonged to Firmin type I, five to type II and one to type IIIa. Both patients with bilateral microtia, were classified as type IIIb. In all cases with unilateral microtia, a good initial projection of the cartilage frame was achieved during the first surgical procedure. Six patients were subjected to a second operation. During 18 months follow up, four patients (16% had complications. Conclusions: This surgical technique that is based on an anatomical surgical classification, achieves favorable and satisfactory results.

  15. Manejo actual de la microtia: redefinición anátomo-quirúrgica / Management of microtia based on a redefinition of its anatomical-surgical classification

    Scientific Electronic Library Online (English)

    Juan Pablo, Sorolla P; Douglas, Arbulo L; Miguel, Obaid G; Carla, Ibarra M; Montserrat, Fontbona; Rodrigo, Cabello P; Pamela, Wisnia C; Ángela, Bautista S.

    2012-12-01

    Full Text Available Objetivos: Reportar y evaluar la efectividad de una técnica quirúrgica, previamente descrita para el tratamiento de microtias, basado en un nuevo concepto de clasificación anátomo-quirúrgica. Material y Método: Estudio retrospectivo de pacientes tratados en el Hospital Militar y Clínica Alemana de S [...] antiago en el Servicio de Cirugía Plástica desde enero de 2008 hasta diciembre de 2010. Se reclutaron a un total de 15 pacientes, 13 (87%) de los cuales eran unilaterales y 2 (13%) bilaterales. A todos los pacientes se les realizó la reconstrucción mediante técnica quirúrgica de Firmin. Resultados: Se operó a 15 pacientes de rango de edad entre 9 y 25 años, con una mediana de 11 años. De los casos unilaterales; 7 correspondían a tipo I de Firmin, 5 casos a tipo II Firmin y un caso tipo IIIa. De los casos bilaterales, ambos tenían microtia tipo IIIb. Se logró en la totalidad de los casos unilaterales una buena proyección inicial del marco cartilaginoso durante el primer tiempo quirúrgico. Seis casos fueron sometidos a un segundo tiempo quirúrgico. Durante el seguimiento mínimo de 18 meses, se observaron complicaciones en 4 (16%) pacientes. Conclusiones: Se comprueba que mediante una técnica basada en la clasificación anátomo-quirúrgica, los resultados a corto plazo fueron favorables y satisfactorios. Abstract in english Background: Incomplete development and growth of the pinna can lead to a small or deformed pinna, called microtia. Aim: To report and evaluate the effectiveness of a surgical technique previously described for the treatment of microtia, based on a new anatomical-surgical classification. Materials an [...] d Methods: Retrospective study of patients treated at two plastic surgery departments from January 2008 to December 2010. We recruited a total of 15 patients aged 9 to 25 years. Thirteen (87%) had unilateral and 2 (13%) bilateral microtia. All patients underwent the surgical reconstructive technique described by Firmin. Results: Among patients with unilateral microtia, seven belonged to Firmin type I, five to type II and one to type IIIa. Both patients with bilateral microtia, were classified as type IIIb. In all cases with unilateral microtia, a good initial projection of the cartilage frame was achieved during the first surgical procedure. Six patients were subjected to a second operation. During 18 months follow up, four patients (16%) had complications. Conclusions: This surgical technique that is based on an anatomical surgical classification, achieves favorable and satisfactory results.

  16. Landmark Detection in Orbital Images Using Salience Histograms

    Science.gov (United States)

    Wagstaff, Kiri L.; Panetta, Julian; Schorghofer, Norbert; Greeley, Ronald; PendletonHoffer, Mary; bunte, Melissa

    2010-01-01

    NASA's planetary missions have collected, and continue to collect, massive volumes of orbital imagery. The volume is such that it is difficult to manually review all of the data and determine its significance. As a result, images are indexed and searchable by location and date but generally not by their content. A new automated method analyzes images and identifies "landmarks," or visually salient features such as gullies, craters, dust devil tracks, and the like. This technique uses a statistical measure of salience derived from information theory, so it is not associated with any specific landmark type. It identifies regions that are unusual or that stand out from their surroundings, so the resulting landmarks are context-sensitive areas that can be used to recognize the same area when it is encountered again. A machine learning classifier is used to identify the type of each discovered landmark. Using a specified window size, an intensity histogram is computed for each such window within the larger image (sliding the window across the image). Next, a salience map is computed that specifies, for each pixel, the salience of the window centered at that pixel. The salience map is thresholded to identify landmark contours (polygons) using the upper quartile of salience values. Descriptive attributes are extracted for each landmark polygon: size, perimeter, mean intensity, standard deviation of intensity, and shape features derived from an ellipse fit.

  17. Measure of Landmark Semantic Salience through Geosocial Data Streams

    Directory of Open Access Journals (Sweden)

    Teriitutea Quesnot

    2014-12-01

    Full Text Available Research in the area of spatial cognition demonstrated that references to landmarks are essential in the communication and the interpretation of wayfinding instructions for human being. In order to detect landmarks, a model for the assessment of their salience has been previously developed by Raubal and Winter. According to their model, landmark salience is divided into three categories: visual, structural, and semantic. Several solutions have been proposed to automatically detect landmarks on the basis of these categories. Due to a lack of relevant data, semantic salience has been frequently reduced to objects’ historical and cultural significance. Social dimension (i.e., the way an object is practiced and recognized by a person or a group of people is systematically excluded from the measure of landmark semantic salience even though it represents an important component. Since the advent of mobile Internet and smartphones, the production of geolocated content from social web platforms—also described as geosocial data—became commonplace. Actually, these data allow us to have a better understanding of the local geographic knowledge. Therefore, we argue that geosocial data, especially Social Location Sharing datasets, represent a reliable source of information to precisely measure landmark semantic salience in urban area.

  18. 36 CFR 62.4 - Natural landmark designation and recognition process.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Natural landmark designation..., DEPARTMENT OF THE INTERIOR NATIONAL NATURAL LANDMARKS PROGRAM § 62.4 Natural landmark designation and recognition process. (a) Identification. Potential national natural landmarks are identified in the...

  19. Development and application of stent-based image guided navigation system for oral and maxillofacial surgery

    International Nuclear Information System (INIS)

    The purpose of this study was to develop a stent-based image guided surgery system and to apply it to oral and maxillofacial surgeries for anatomically complex sites. We devised a patient-specific stent for patient-to-image registration and navigation. Three dimensional positions of the reference probe and the tool probe were tracked by an optical camera system and the relative position of the handpiece drill tip to the reference probe was monitored continuously on the monitor of a PC. Using 8 landmarks for measuring accuracy, the spatial discrepancy between CT image coordinate and physical coordinate was calculated for testing the normality. The accuracy over 8 anatomical landmarks showed an overall mean of 0.56 ± 0.16 mm. The developed system was applied to a surgery for a vertical alveolar bone augmentation in right mandibular posterior area and possible interior alveolar nerve injury case of an impacted third molar. The developed system provided continuous monitoring of invisible anatomical structures during operation and 3D information for operation sites. The clinical challenge showed sufficient accuracy and availability of anatomically complex operation sites. The developed system showed sufficient accuracy and availability in oral and maxillofacial surgeries for anatomically complex sites.

  20. Development and application of stent-based image guided navigation system for oral and maxillofacial surgery

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Woo Jin; Kim, Dae Seung [Interdisciplinary Program in Radiation Applied Life Science, Dental Research Institute and BK21, College of Medicine, Seoul National University, Seoul (Korea, Republic of); Yi, Won Jin; Lee, Sam Sun; Choi, Soon Chul; Heo, Min Suk; Huh, Kyung Hoe; Kim, Myung Jin; Lee, Jee Ho [Department of Oral and Maxillofacial Surgery, Dental Research Institute, School of Dentistry, Seoul National University, Seoul (Korea, Republic of)

    2009-09-15

    The purpose of this study was to develop a stent-based image guided surgery system and to apply it to oral and maxillofacial surgeries for anatomically complex sites. We devised a patient-specific stent for patient-to-image registration and navigation. Three dimensional positions of the reference probe and the tool probe were tracked by an optical camera system and the relative position of the handpiece drill tip to the reference probe was monitored continuously on the monitor of a PC. Using 8 landmarks for measuring accuracy, the spatial discrepancy between CT image coordinate and physical coordinate was calculated for testing the normality. The accuracy over 8 anatomical landmarks showed an overall mean of 0.56 {+-} 0.16 mm. The developed system was applied to a surgery for a vertical alveolar bone augmentation in right mandibular posterior area and possible interior alveolar nerve injury case of an impacted third molar. The developed system provided continuous monitoring of invisible anatomical structures during operation and 3D information for operation sites. The clinical challenge showed sufficient accuracy and availability of anatomically complex operation sites. The developed system showed sufficient accuracy and availability in oral and maxillofacial surgeries for anatomically complex sites.

  1. Quantification of radiographic image quality based on patient anatomical contrast-to-noise ratio: a preliminary study with chest images

    Science.gov (United States)

    Lin, Yuan; Wang, Xiaohui; Sehnert, William J.; Foos, David H.; Barski, Lori; Samei, Ehsan

    2010-02-01

    The quality of a digital radiograph for diagnostic imaging depends on many factors, such as the capture system DQE and MTF, the exposure technique factors, the patient anatomy, and the particular image processing method and processing parameters used. Therefore, the overall image quality as perceived by the radiologists depends on many factors. This work explores objective image quality metrics directly from display-ready patient images. A preliminary study was conducted based on a multi-frequency analysis of anatomy contrast and noise magnitude from 250 computed radiography (CR) chest radiographs (150 PA, 50 AP captured with anti-scatter grids, and 50 AP without grids). The contrast and noise values were evaluated in different sub-bands separately according to their frequency properties. Contrast-Noise ratio (CNR) was calculated, the results correlated well with the human observers' overall impression on the images captured with and without grids.

  2. Reference Man anatomical model

    Energy Technology Data Exchange (ETDEWEB)

    Cristy, M.

    1994-10-01

    The 70-kg Standard Man or Reference Man has been used in physiological models since at least the 1920s to represent adult males. It came into use in radiation protection in the late 1940s and was developed extensively during the 1950s and used by the International Commission on Radiological Protection (ICRP) in its Publication 2 in 1959. The current Reference Man for Purposes of Radiation Protection is a monumental book published in 1975 by the ICRP as ICRP Publication 23. It has a wealth of information useful for radiation dosimetry, including anatomical and physiological data, gross and elemental composition of the body and organs and tissues of the body. The anatomical data includes specified reference values for an adult male and an adult female. Other reference values are primarily for the adult male. The anatomical data include much data on fetuses and children, although reference values are not established. There is an ICRP task group currently working on revising selected parts of the Reference Man document.

  3. Anatomical Basis of the Myofascial Trigger Points of the Trapezius Muscle / Bases Anatómicas de los Puntos de Gatillo Miofasciales del Músculo Trapecio

    Scientific Electronic Library Online (English)

    Flávia Emi, Akamatsu; Samir, Saleh; Henrique Trombini, Pinesi; Katarina Reichmann, Rodrigues; Cintia Benedicto, Zandoná; Mauro, Andrade; Alfredo Luiz, Jacomo.

    2013-09-01

    Full Text Available El objetivo de este estudio fue correlacionar los sitios de entrada de los ramos del nervio accesorio en el músculo trapecio con placas motoras y los puntos de gatillo miofasciales. A pesar de las correlaciones anatomoclínicas se constituyeren en la principal característica de los puntos de gatillo, [...] no hay informes en la literatura describiendo sobre la distribución de los ramos del nervio accesorio y su relación anatómica con los puntos de gatillo. Ambos músculos trapecio de doce cadáveres adultos fueron disecados por los autores (profesores de anatomía y estudiantes de postgrado en Medicina) para observar el punto exacto donde los ramos del nervio accesorio espinal penetraban en el vientre muscular. La disección se llevó a cabo respetando las capas estratigráficas para preservar la inervación del músculo ubicada profundamente a éste. Ocho puntos fueron identificados: En todos los casos correspondieron a la descripción clínica de los puntos gatillo miofasciales y eran comunes a todos los cadáveres. Esta correlación anatomoclínica entre la ramificación del nervio espinal accesorio y los puntos de gatillo miofascial es útil para una mejor comprensión de la fisiopatología de los puntos gatillo y puede proporcionar una base para un abordaje diagnóstico y terapéutico racional para estos trastornos. Abstract in english This study aimed to bring the trapezius muscle, knowledge of the locations where the accessory nerve branches enter the muscle belly to reach the motor endplates and find myofascial trigger points (MTPs). Although anatomoclinical correlations represent a major feature of MTP, no previous reports des [...] cribing the distribution of the accessory nerve branches and their anatomical relationship with MTP are found in the literature. Both trapezius muscles from twelve adult cadavers were carefully dissected by the authors (anatomy professors and medical graduate students) to observe the exact point where the branches of the spinal accessory nerve entered the muscle belly. Dissection was performed through stratigraphic layers to preserve the motor innervation of the trapezius muscle, which is located deep in the muscle. Eight points were identified: In all cases, these locations corresponded to clinically described MTPs. The eight points where common in these twelve cadavers. This type of clinical correlation between spinal accessory nerve branching and MPT is useful to achieve a better understanding of the anatomical correlation of MTP and the physiopathology of these disorders and may provide a scientific basis for their treatment, providing useful additional information to therapists to achieve better diagnoses and improve therapeutic approaches.

  4. Investigation of factors affecting hypothermic pelvic tissue cooling using bio-heat simulation based on MRI-segmented anatomic models.

    Science.gov (United States)

    Lin, Yuting; Lin, Wei-Ching; Fwu, Peter T; Shih, Tzu-Ching; Yeh, Lee-Ren; Su, Min-Ying; Chen, Jeon-Hor

    2015-10-01

    This study applied a simulation method to map the temperature distribution based on magnetic resonance imaging (MRI) of individual patients, and investigated the influence of different pelvic tissue types as well as the choice of thermal property parameters on the efficiency of endorectal cooling balloon (ECB). MR images of four subjects with different prostate sizes and pelvic tissue compositions, including fatty tissue and venous plexus, were analyzed. The MR images acquired using endorectal coil provided a realistic geometry of deformed prostate that resembled the anatomy in the presence of ECB. A single slice with the largest two-dimensional (2D) cross-sectional area of the prostate gland was selected for analysis. The rectal wall, prostate gland, peri-rectal fatty tissue, peri-prostatic fatty tissue, peri-prostatic venous plexus, and urinary bladder were manually segmented. Pennes' bioheat thermal model was used to simulate the temperature distribution dynamics, by using an in-house finite element mesh based solver written in MATLAB. The results showed that prostate size and periprostatic venous plexus were two major factors affecting ECB cooling efficiency. For cases with negligible amount of venous plexus and small prostate, the average temperature in the prostate and neurovascular bundles could be cooled down to 25 °C within 30 min. For cases with abundant venous plexus and large prostate, the temperature could not reach 25 °C at the end of 3 h cooling. Large prostate made the cooling difficult to propagate through. The impact of fatty tissue on cooling effect was small. The filling of bladder with warm urine during the ECB cooling procedure did not affect the temperature in the prostate or NVB. In addition to the 2D simulation, in one case a 3D pelvic model was constructed for volumetric simulation. It was found that the 2D slice with the largest cross-sectional area of prostate had the most abundant venous plexus, and was the most difficult slice to cool, thus it may provide a conservative prediction of the cooling effect. This feasibility study demonstrated that the simulation tool could potentially be used for adjusting the setting of ECB for individual patients during hypothermic radical prostatectomy. Further studies using MR thermometry are required to validate the in silico results obtained using simulation. PMID:26198131

  5. Pilot study: Computer-based virtual anatomical interactivity for rehabilitation of individuals with chronic acquired brain injury

    Directory of Open Access Journals (Sweden)

    C. Douglas Simmons, PhD, OTR/L, FAOTA

    2014-06-01

    Full Text Available Deficiencies in upper-limb motor function and executive functioning can compromise an affected individual’s ability to complete everyday activities. Impaired motor and executive functioning therefore pose a risk to increasing numbers of veterans who have been diagnosed with acquired brain injury. This article reports on changes in upper-limb motor function and executive functioning of 12 adult participants with chronic acquired brain injury using a novel, computer-based, motor and cognitive rehabilitation program called PreMotor Exercise Games (PEGs. Manual muscle, goniometric range of motion, and dynamometer assessments were used to determine motor functioning while the Executive Function Performance Test measured cognitive functioning. A three-level repeated measures design was conducted to determine changes pre- and postintervention. Participants demonstrated significant improvement in shoulder (p = 0.01 and wrist (p = 0.01 range of motion and clinically relevant improvement for elbow range of motion. Participants demonstrated clinically relevant improvement in shoulder, elbow, and wrist strength. Finally, participants demonstrated significant improvement in executive functioning (p < 0.05. Using PEGs as a modality for both motor and cognitive intervention is a potentially beneficial adjunct to rehabilitation and warrants further study.

  6. Modeling and matching of landmarks for automation of Mars Rover localization

    Science.gov (United States)

    Wang, Jue

    The Mars Exploration Rover (MER) mission, begun in January 2004, has been extremely successful. However, decision-making for many operation tasks of the current MER mission and the 1997 Mars Pathfinder mission is performed on Earth through a predominantly manual, time-consuming process. Unmanned planetary rover navigation is ideally expected to reduce rover idle time, diminish the need for entering safe-mode, and dynamically handle opportunistic science events without required communication to Earth. Successful automation of rover navigation and localization during the extraterrestrial exploration requires that accurate position and attitude information can be received by a rover and that the rover has the support of simultaneous localization and mapping. An integrated approach with Bundle Adjustment (BA) and Visual Odometry (VO) can efficiently refine the rover position. However, during the MER mission, BA is done manually because of the difficulty in the automation of the cross-sitetie points selection. This dissertation proposes an automatic approach to select cross-site tie points from multiple rover sites based on the methods of landmark extraction, landmark modeling, and landmark matching. The first step in this approach is that important landmarks such as craters and rocks are defined. Methods of automatic feature extraction and landmark modeling are then introduced. Complex models with orientation angles and simple models without those angles are compared. The results have shown that simple models can provide reasonably good results. Next, the sensitivity of different modeling parameters is analyzed. Based on this analysis, cross-site rocks are matched through two complementary stages: rock distribution pattern matching and rock model matching. In addition, a preliminary experiment on orbital and ground landmark matching is also briefly introduced. Finally, the reliability of the cross-site tie points selection is validated by fault detection, which considers the mapping capability of MER cameras and the reason for mismatches. Fault detection strategies are applied in each step of the cross-site tie points selection to automatically verify the accuracy. The mismatches are excluded and localization errors are minimized. The method proposed in this dissertation is demonstrated with the datasets from the 2004 MER mission (traverse of 318 m) as well as the simulated test data at Silver Lake (traverse of 5.5 km), California. The accuracy analysis demonstrates that the algorithm is efficient at automatically selecting a sufficient number of well-distributed high-quality tie points to link the ground images into an image network for BA. The method worked successfully along with a continuous 1.1 km stretch. With the BA performed, highly accurate maps can be created to help the rover to navigate precisely and automatically. The method also enables autonomous long-range Mars rover localization.

  7. Undecidability and temporal logic: some landmarks from Turing to the present

    DEFF Research Database (Denmark)

    Goranko, Valentin

    2012-01-01

    This is a selective survey and discussion of some of the landmark undecidability results in temporal logic, beginning with Turing's undecidability of the Halting problem which, in retrospect, can be regarded as the historically first undecidability result for a suitable temporal logic over configuration graphs of Turing machines. I will discuss some of the natural habitats of undecidable temporal logics, such as first-order, interval-based and real time temporal logics, as well as some extension...

  8. Delivering high-resolution landmarks using inkjet micropatterning for spatial monitoring of leaf expansion

    OpenAIRE

    Cronk Quentin CB; Beyer Simon T; Wang Lisheng; Walus Konrad

    2011-01-01

    Abstract Background Inkjet micropatterning is a versatile deposition technique with broad applications in numerous fields. However, its application in plant science is largely unexplored. Leaf expansion is one of the most important parameters in the field of plant science and many methods have been developed to examine differential expansion rates of different parts of the leaf lamina. Among them, methods based on the tracking of natural landmarks through digital imaging require a complicated...

  9. Motion estimation in cardiac fluorescence imaging with scale-space landmarks and optical flow: a comparative study.

    Science.gov (United States)

    Rodriguez, M P; Nygren, A

    2015-02-01

    Motion artifacts are a major disadvantage of cardiac optical mapping studies. Pixel misalignment due to contraction is a main cause of the presence of gross motion artifacts in action potential recordings. This study is focused on methods for identifying landmarks and tracking the motion of cardiac tissue for preparations in optical mapping recordings. This is a first step toward our long-term goal to implement a landmark-based image registration technique to correct for pixel misalignment in cardiac optical mapping fluorescence videos and, hence, for gross motion artifacts. Preliminary results for the registration step are presented as an initial proof of concept. The characteristics of the optical mapping images are challenging, since their lack of contrast and well-defined features impose a limitation on the techniques than can be used for landmark selection and motion tracking. This paper compares results of motion estimation of the cardiac surface with two approaches that do not rely on high-contrast features: 1) Scale-invariant feature transform (SIFT) detected "keypoints," to be used as landmarks for motion tracking, as well as 2) a classical global optical flow (OF) algorithm. Both are applied to low-contrast and low-resolution cardiac fluorescence images. We demonstrate that the performance of SIFT is superior to that of OF for pixel motion tracking in cardiac optical mapping images with simulated motion. Results for action potential recovery and action potential duration calculation after landmark-based image registration show that SIFT landmark-based registration yields superior performance in this regard as well. PMID:25350913

  10. On landmark selection and sampling in high-dimensional data analysis

    CERN Document Server

    Belabbas, Mohamed-Ali

    2009-01-01

    In recent years, the spectral analysis of appropriately defined kernel matrices has emerged as a principled way to extract the low-dimensional structure often prevalent in high-dimensional data. Here we provide an introduction to spectral methods for linear and nonlinear dimension reduction, emphasizing ways to overcome the computational limitations currently faced by practitioners with massive datasets. In particular, a data subsampling or landmark selection process is often employed to construct a kernel based on partial information, followed by an approximate spectral analysis termed the Nystrom extension. We provide a quantitative framework to analyse this procedure, and use it to demonstrate algorithmic performance bounds on a range of practical approaches designed to optimize the landmark selection process. We compare the practical implications of these bounds by way of real-world examples drawn from the field of computer vision, whereby low-dimensional manifold structure is shown to emerge from high-di...

  11. Common osteoporosis: anatomical, clinical and therapeutical aspects

    International Nuclear Information System (INIS)

    The paper presents anatomical, clinical and therapeutical aspects of common osteoporosis as well as exploration techniques based on X-ray, gamma-ray and neutron activation methods. The radioisotopes used in gamma ray absorption are: 125 I, 241 Am and 153 Ga. The neutron activation is based on natural isotope 48Ca becoming 49Ca isotope after radiative neutron capture

  12. Validation of simple quantification methods for 18F FP CIT PET Using Automatic Delineation of volumes of interest based on statistical probabilistic anatomical mapping and isocontour margin setting

    International Nuclear Information System (INIS)

    18F FP CIT positron emission tomography (PET) is an effective imaging for dopamine transporters. In usual clinical practice, 18F FP CIT PET is analyzed visually or quantified using manual delineation of a volume of interest (VOI) fir the stratum. in this study, we suggested and validated two simple quantitative methods based on automatic VOI delineation using statistical probabilistic anatomical mapping (SPAM) and isocontour margin setting. Seventy five 18F FP CIT images acquired in routine clinical practice were used for this study. A study-specific image template was made and the subject images were normalized to the template. afterwards, uptakes in the striatal regions and cerebellum were quantified using probabilistic VOI based on SPAM. A quantitative parameter, QSPAM, was calculated to simulate binding potential. additionally, the functional volume of each striatal region and its uptake were measured in automatically delineated VOI using isocontour margin setting. Uptake volume product(QUVP) was calculated for each striatal region. QSPAMand QUVPwas calculated for each visual grading and the influence of cerebral atrophy on the measurements was tested. Image analyses were successful in all the cases. Both the QSPAMand QUVPwere significantly different according to visual grading (0.001). The agreements of QUVPand QSPAMwith visual grading were slight to fair for the caudate nucleus (K= 0.421 and 0.291, respectively) and good to prefect to the putamen (K=0.663 and 0.607, respectively). Also, QSPAMand QUVPhad a significant correlation with each other (0.001). Cerebral atrophy made a significant difference in QSPAMand QUVPof the caudate nuclei regions with decreased 18F FP CIT uptake. Simple quantitative measurements of QSPAMand QUVPshowed acceptable agreement with visual grad-ing. although QSPAMin some group may be influenced by cerebral atrophy, these simple methods are expected to be effective in the quantitative analysis of F FP CIT PET in usual clinical practice

  13. Landmark learning by the Ozark zigzag salamander Plethodon angusticlavius

    Directory of Open Access Journals (Sweden)

    Adam L. CRANE, Alicia MATHIS

    2011-08-01

    Full Text Available Although salamanders have been shown to respond to classical conditioning, spatial learning has been largely unstudied. We tested whether salamanders could learn to locate foraging areas by using landmarks. We trained 10 salamanders Plethodon angusticlavius to use landmarks (small rocks to locate patches within the arena containing food (blackworms Lumbriculus variegatus. At the corners of each square testing arena were four plastic dishes, one containing blackworms and the other three empty. A rock was placed in front of the dish containing blackworms, and the location of the food-dish was randomly chosen for each training trial. A control group was also trained to feed on blackworms in the presence of a rock, but the rock was positioned randomly among the four dish locations so that the rock was not a reliable landmark for the worms. Although the length of the training period for individual salamanders varied (22–38 trainings per individual, the mean number of trainings for salamanders in the control and experimental groups was equal (30 training trials. During testing, no blackworms were present to eliminate any visual or chemical cues emanating directly from the prey. Individuals trained with the rock landmarks spent significantly more time in the area of the landmark than did control salamanders [Current Zoology 57 (4: 485–490, 2011].

  14. Correction of dental artifacts within the anatomical surface in PET/MRI using active shape models and k-nearest-neighbors

    Science.gov (United States)

    Ladefoged, Claes N.; Andersen, Flemming L.; Keller, Sune H.; Beyer, Thomas; Højgaard, Liselotte; Lauze, François

    2014-03-01

    In combined PET/MR, attenuation correction (AC) is performed indirectly based on the available MR image information. Metal implant-induced susceptibility artifacts and subsequent signal voids challenge MR-based AC. Several papers acknowledge the problem in PET attenuation correction when dental artifacts are ignored, but none of them attempts to solve the problem. We propose a clinically feasible correction method which combines Active Shape Models (ASM) and k- Nearest-Neighbors (kNN) into a simple approach which finds and corrects the dental artifacts within the surface boundaries of the patient anatomy. ASM is used to locate a number of landmarks in the T1-weighted MR-image of a new patient. We calculate a vector of offsets from each voxel within a signal void to each of the landmarks. We then use kNN to classify each voxel as belonging to an artifact or an actual signal void using this offset vector, and fill the artifact voxels with a value representing soft tissue. We tested the method using fourteen patients without artifacts, and eighteen patients with dental artifacts of varying sizes within the anatomical surface of the head/neck region. Though the method wrongly filled a small volume in the bottom part of a maxillary sinus in two patients without any artifacts, due to their abnormal location, it succeeded in filling all dental artifact regions in all patients. In conclusion, we propose a method, which combines ASM and kNN into a simple approach which, as the results show, succeeds to find and correct the dental artifacts within the anatomical surface.

  15. Correction of dental artifacts within the anatomical surface in PET/MRI using Active Shape Models and k-Nearest-Neighbors

    DEFF Research Database (Denmark)

    Ladefoged, Claes N.; Andersen, Flemming L.

    2014-01-01

    n combined PET/MR, attenuation correction (AC) is performed indirectly based on the available MR image information. Metal implant-induced susceptibility artifacts and subsequent signal voids challenge MR-based AC. Several papers acknowledge the problem in PET attenuation correction when dental artifacts are ignored, but none of them attempts to solve the problem. We propose a clinically feasible correction method which combines Active Shape Models (ASM) and k- Nearest-Neighbors (kNN) into a simple approach which finds and corrects the dental artifacts within the surface boundaries of the patient anatomy. ASM is used to locate a number of landmarks in the T1-weighted MR-image of a new patient. We calculate a vector of offsets from each voxel within a signal void to each of the landmarks. We then use kNN to classify each voxel as belonging to an artifact or an actual signal void using this offset vector, and fill the artifact voxels with a value representing soft tissue. We tested the method using fourteen patients without artifacts, and eighteen patients with dental artifacts of varying sizes within the anatomical surface of the head/neck region. Though the method wrongly filled a small volume in the bottom part of a maxillary sinus in two patients without any artifacts, due to their abnormal location, it succeeded in filling all dental artifact regions in all patients. In conclusion, we propose a method, which combines ASM and kNN into a simple approach which, as the results show, succeeds to find and correct the dental artifacts within the anatomical surface.

  16. A clinical test and application research of IMRT dose verification system based on patient's anatomical structure and on-line dosimetry

    International Nuclear Information System (INIS)

    Objective: To test a three-dimensional dose verification system, which reconstructing dose to anatomy based on modeling and online measurements (RDBMOM), and to evaluate the accuracy and feasibility of its application in clinical intensity-modulated radiotherapy (IMRT) quality assurance. Methods: Phantom plans of regular and irregular fields were selected for the testing. All test plans were implemented and the dose distributions were measured using the thimble ion-chamber and two-dimensional ion-chamber array, the accuracy of RDBMOM were then evaluated by comparing the corresponding results.Two practical treated nasopharyngeal carcinoma IMRT plans were verified with RDBMOM and the clinic significance were valued. Results: Compared with measurements of the thimble ion-chamber, deviations of RDBMOM were within 1% in all tested cases except small field of 3 cm x 3 cm. The largest deviation of reconstructed dose in IMRT cases was 2.12%. The dose profile reconstructed by RDBMOM coincided with the measurement using two-dimensional ion-chamber array. The ? rates (3%/3 mm) were 94.56% - 100%. The RDBMOM verification of IMRT cases shown that the ? rate > 99% in total and > 98% in planning target volume,deviation in D95 <0.4%, but the largest deviations in mean dose of the parotids and lens were 2.97% and 59.58% respectively. Conclusions: Accuracy of the tested system satisfies the demand of IMRT dose verification. RDBMOM is able to provide information of volumetric dosimetry and anatomical location of dose error, which is benefit for evaluating the clinical value of verification results. (authors)

  17. Validation of a Model-Based Segmentation Approach to Propagating Normal Anatomic Regions of Interest Through the 10 Phases of Respiration

    International Nuclear Information System (INIS)

    Purpose: To validate a model-based segmentation (MBS) algorithm in a commercial radiation treatment planning system for use in propagating the contours of normal anatomic regions of interest (ROIs) through the respiratory phases that constitute a four-dimensional (4D) computed tomography (CT) image data set. Methods and Materials: The 4D CT data sets for 12 patients treated for non-small-cell lung cancer were acquired. Five ROIs were selected for delineation: right and left lungs, spinal cord, heart, and esophagus. These ROIs were manually delineated on the CT data set corresponding to the end-inspiration respiratory phase (0%). An MBS algorithm implemented on the treatment planning system propagated the ROIs sequentially through the respiratory phases that constituted the 4D CT data sets, concluding with the 0% phase data set, which was propagated from the 90% phase data set. The propagated ROIs on the 0% phase were compared with the original ROIs on that phase by using visual assessment and a quantitative measure of coincidence. Results: Acceptable propagation accuracy within 1 mm of uncertainty was achieved for lungs and spinal cord. Propagation of the heart produced slightly larger contours that were similar to interphysician variations in contouring the heart. The esophagus was poorly propagated because of lack of tissue contrast and definitive shape. Conclusions: The MBS propagation is a promising tool for efficiently propagating contours through the different phases of respiration. However, propagating the esophagus through this technique may be difficult because of the lack of definitive shape and clearer boundaries from surrounding tissue

  18. Blocking between landmarks during 2-D (touchscreen) and 3-D (ARENA) search tasks with pigeons.

    Science.gov (United States)

    Leising, Kenneth J; Wong, Jared; Ruprecht, Chad M; Blaisdell, Aaron P

    2014-12-01

    Many studies investigating cue competition have focused on the blocking effect. We investigated the blocking effect with pigeons using a landmark-based spatial search task in both a touchscreen preparation (Exp. 1a) and an automated remote environmental navigation apparatus (Exp. 1b). In Phase 1, two landmarks (LMs: A and Z) appeared on separate trials as colored circles among a row of eight (touchscreen) or six (ARENA) identical response units. Subjects were rewarded for pecking at a target response unit to the right of LM A and to the left of an extraneous LM, Z. During the blocking trials in Phase 2, LM X was presented in compound with a second LM (A) that had been previously trained. On control trials, LM Y was presented in compound with LM B and a target in the same manner as in the trials of AX, except that neither landmark had previously been trained with the target. All subjects were then tested with separate trials of A, X, B, and Y. Testing revealed poor spatial control by X relative to A and Y. We report the first evidence for a spatial-blocking effect in pigeons and additional support for associative effects (e.g., blocking) occurring under similar conditions (e.g., training sessions, spatial relationships, etc.) in 3-D and 2-D search tasks. PMID:25209533

  19. Automated extraction of skeletal muscles from torso X-ray CT images based on anatomical positional information between skeleton and skeletal muscles

    International Nuclear Information System (INIS)

    We propose an automated approach to extract skeletal muscles in torso X-ray CT images. It transforms 3-D anatomy into 2-D stretched images for simplifying anatomical relationships to getting pathognomonical points. The experimental results show that the proposed method was effective to extract skeletal muscles. (author)

  20. Anatomical organization of aortic arch variations in the India: embryological basis and review / Organização anatômica das variações do arco aórtico na população indiana: base e revisão embriológica

    Scientific Electronic Library Online (English)

    Soubhagya R., Nayak; Mangala M., Pai; Latha V., Prabhu; Sujatha, D' Costa; Prakash, Shetty.

    2006-06-01

    Full Text Available OBJETIVOS: Determinar a porcentagem e o tipo de variações do arco aórtico em indivíduos indianos, bem como sua importância clínica e cirúrgica e base embriológica. PACIENTES E MÉTODOS: Em nossa investigação, os padrões de ramificação do arco aórtico foram estudados em 62 cadáveres fixados em formali [...] na de ambos os sexos, de origem indiana e com idade entre 45 e 79 anos. As dissecações foram realizadas em cadáveres preservados em formalina, e as variações do arco aórtico foram observadas após a exposição das regiões torácica e cervical durante a dissecação de rotina de alunos da graduação do Kasturba Medical College, Mangalore, Índia. RESULTADOS: O arco aórtico normal de três ramificações foi encontrado em 56 cadáveres (91,4%); as variações foram encontradas em seis cadáveres (9,6%); 4,8% apresentavam origem comum das artérias carótidas; 1,6% tinham seqüência binominada, e o mesmo espécime tinha a origem da artéria coronária esquerda diretamente no arco aórtico; 1,6% apresentavam a origem da artéria subclávia direita diretamente na aorta; 1,6% tinham como ramificação do arco aórtico uma artéria vertebral esquerda. Cinco de seis cadáveres com padrão de ramificação anômalo do arco aórtico eram do sexo feminino. Um cadáver do sexo masculino apresentou origem anômala da artéria vertebral esquerda diretamente no arco. CONCLUSÃO: O amplo espectro de variações nos padrões anatômicos das ramificações do arco aórtico na população indiana estava em concordância com outras populações mundiais. Embora as origens anômalas das ramificações do arco aórtico sejam meramente variações anatômicas, informações precisas sobre elas é essencial para a cirurgia vascular na região do tórax, cabeça e pescoço. Abstract in english OBJECTIVES: To determine the percentage and type of aortic arch variations in Indian subjects and their clinical and surgical importance and embryological basis. PATIENTS AND METHOD: In our investigation, branching patterns of the aortic arch were studied in 62 formalin-fixed cadavers of both sexes [...] of Indian origin, aged 45-79. The dissections were carried out in formalin-preserved cadavers and the aortic arch variations were observed after exposing the thoracic and cervical region during routine dissection of undergraduate students of Indian origin in Kasturba Medical College, Mangalore. RESULTS: The usual three-branched aortic arch was found in 56 cadavers (91.4%); variations were found in six cadavers (9.6%); 4.8% presented common origin of the carotid arteries; 1.6% had bi-innominate sequence, and the same specimen had left coronary artery arising from arch of aorta directly; 1.6% presented right subclavian artery arising directly from the aorta; 1.6% had left vertebral artery a branch of aortic arch. Five out of six cadavers with anomalous aortic arch branching pattern were females. One male cadaver presented anomalous origin of left vertebral artery directly from the arch. CONCLUSION: The wide spectrum of variations in the anatomical arrangements of the aortic arch branches in the Indian population was at par with other populations of the world. Although anomalous origins of the aortic arch branches are merely anatomic variants, accurate information about them is vital for vascular surgery in the thorax, head and neck region.

  1. Anatomical organization of aortic arch variations in the India: embryological basis and review Organização anatômica das variações do arco aórtico na população indiana: base e revisão embriológica

    Directory of Open Access Journals (Sweden)

    Soubhagya R. Nayak

    2006-06-01

    Full Text Available OBJECTIVES: To determine the percentage and type of aortic arch variations in Indian subjects and their clinical and surgical importance and embryological basis. PATIENTS AND METHOD: In our investigation, branching patterns of the aortic arch were studied in 62 formalin-fixed cadavers of both sexes of Indian origin, aged 45-79. The dissections were carried out in formalin-preserved cadavers and the aortic arch variations were observed after exposing the thoracic and cervical region during routine dissection of undergraduate students of Indian origin in Kasturba Medical College, Mangalore. RESULTS: The usual three-branched aortic arch was found in 56 cadavers (91.4%; variations were found in six cadavers (9.6%; 4.8% presented common origin of the carotid arteries; 1.6% had bi-innominate sequence, and the same specimen had left coronary artery arising from arch of aorta directly; 1.6% presented right subclavian artery arising directly from the aorta; 1.6% had left vertebral artery a branch of aortic arch. Five out of six cadavers with anomalous aortic arch branching pattern were females. One male cadaver presented anomalous origin of left vertebral artery directly from the arch. CONCLUSION: The wide spectrum of variations in the anatomical arrangements of the aortic arch branches in the Indian population was at par with other populations of the world. Although anomalous origins of the aortic arch branches are merely anatomic variants, accurate information about them is vital for vascular surgery in the thorax, head and neck region.OBJETIVOS: Determinar a porcentagem e o tipo de variações do arco aórtico em indivíduos indianos, bem como sua importância clínica e cirúrgica e base embriológica. PACIENTES E MÉTODOS: Em nossa investigação, os padrões de ramificação do arco aórtico foram estudados em 62 cadáveres fixados em formalina de ambos os sexos, de origem indiana e com idade entre 45 e 79 anos. As dissecações foram realizadas em cadáveres preservados em formalina, e as variações do arco aórtico foram observadas após a exposição das regiões torácica e cervical durante a dissecação de rotina de alunos da graduação do Kasturba Medical College, Mangalore, Índia. RESULTADOS: O arco aórtico normal de três ramificações foi encontrado em 56 cadáveres (91,4%; as variações foram encontradas em seis cadáveres (9,6%; 4,8% apresentavam origem comum das artérias carótidas; 1,6% tinham seqüência binominada, e o mesmo espécime tinha a origem da artéria coronária esquerda diretamente no arco aórtico; 1,6% apresentavam a origem da artéria subclávia direita diretamente na aorta; 1,6% tinham como ramificação do arco aórtico uma artéria vertebral esquerda. Cinco de seis cadáveres com padrão de ramificação anômalo do arco aórtico eram do sexo feminino. Um cadáver do sexo masculino apresentou origem anômala da artéria vertebral esquerda diretamente no arco. CONCLUSÃO: O amplo espectro de variações nos padrões anatômicos das ramificações do arco aórtico na população indiana estava em concordância com outras populações mundiais. Embora as origens anômalas das ramificações do arco aórtico sejam meramente variações anatômicas, informações precisas sobre elas é essencial para a cirurgia vascular na região do tórax, cabeça e pescoço.

  2. Anatomical variations of the saphenous vein arc.

    Directory of Open Access Journals (Sweden)

    José Luis Ciucci

    2010-11-01

    Full Text Available There are many anatomical variations presented by the tributaries of the saphenous vein at the saphenous – femoral junction .In anatomical texts, they are plotted as usual tributaries to the femoral vein, presentations that are not found during routine surgical practice. Knowledge of the sapheno- femoral vein junction is imperative for the surgeon when operating the venous system of lower limbs, in order to avoid accidents and prevent intraoperative varicose recurrences. The aim of the present paper is to demonstrate which of the anatomical variations of the arc of the great saphenous vein is shown more often, contributing to the description of the anatomy of the region and its name in the anatomical terminology. The present work is based on experience of one hundred dissections (n = 100 of the femoral inguinal region in human cadavers fixed with formol aqueous solution of 5% v / v, twenty (n = 20 of which were filled with latex via endovascular before its fixation. The basic scheme of the arc of the great saphenous vein receives the following tributaries: the superficial circumflex iliac vein, superficial epigastric vein [subcutaneous abdominal vein], external pudendal veins, accessory vein of the thigh [dorsal thigh], inter saphenous vein [Giacomini vein]. Inter saphenous vein was observed [Giacomini vein] in a large percentage of the sample (66%. On 77% of the cases, a single saphenous trunk was found, 22% of duplication and triplication 1%. Exceptionally small caliber veins reach the common femoral vein on its inner side, draining the pudendal region, may correspond to the third vein pudendal described by Vilanova, or a tributary of the arc that ends in isolation while the rest of the arc remains on the basic disposition. Successful surgery of the saphenous vein arc is based on an optimal anatomical knowledge of the sapheno - femoral junction, its anatomical variations and relationships.

  3. Anatomically Plausible Surface Alignment and Reconstruction

    DEFF Research Database (Denmark)

    Paulsen, Rasmus R.; Larsen, Rasmus

    With the increasing clinical use of 3D surface scanners, there is a need for accurate and reliable algorithms that can produce anatomically plausible surfaces. In this paper, a combined method for surface alignment and reconstruction is proposed. It is based on an implicit surface representation...

  4. Delivering high-resolution landmarks using inkjet micropatterning for spatial monitoring of leaf expansion

    Directory of Open Access Journals (Sweden)

    Cronk Quentin CB

    2011-01-01

    Full Text Available Abstract Background Inkjet micropatterning is a versatile deposition technique with broad applications in numerous fields. However, its application in plant science is largely unexplored. Leaf expansion is one of the most important parameters in the field of plant science and many methods have been developed to examine differential expansion rates of different parts of the leaf lamina. Among them, methods based on the tracking of natural landmarks through digital imaging require a complicated setup in which the leaf must remain fixed and under tension. Furthermore, the resolution is limited to that of the natural landmarks, which are often difficult to find, particularly in young leaves. To study the fine scale expansion dynamics of the leaf lamina using artificial landmarks it is necessary to place small, noninvasive marks on a leaf surface and then recover the location of those marks after a period of time. Results To monitor leaf expansion in two dimensions, at very fine scales, we used a custom designed inkjet micropatterning system to print a grid composed of c. 0.19 mm2 cells on small developing leaves of ivy (Hedera helix using 40 μm dots at a spacing of c. 91 μm. The leaves in different growing stages were imaged under magnification to extract the coordinates of the marks which were then used in subsequent computer-assisted leaf expansion analyses. As an example we obtained quantified global and local expansion information and created expansion maps over the entire leaf surface. The results reveal a striking pattern of fine-scale expansion differences over short periods of time. In these experiments, the base of the leaf is a "cold spot" for expansion, while the leaf sinuses are "hot spots" for expansion. We have also measured a strong shading effect on leaf expansion. We discuss the features required to build an inkjet printing apparatus optimized for use in plant science, which will further maximize the range of tissues that can be printed at these scales. Conclusions To apply inkjet micropatterning to plant studies, we have successfully delivered landmarks on ivy leaf surfaces and achieved high-resolution, two-dimensional monitoring of leaf expansion at different growing stages. The measurement is capable of reliably identifying the fine scale changes during plant growth. As well as delivering landmarks, this technology may be used to deliver microscale targeted biological components such as growth hormones, and possibly be used to pattern sensors directly on the leaves.

  5. Automated anatomical labeling of MRI brain data using spatial atlas warping in a finite-element framework

    Science.gov (United States)

    Meier, Dominik S.; Fisher, Elizabeth; Tkach, Jean A.; Masaryk, Thomas J.; Cohen, Jeffrey A.; Cornhill, J. Fredrick

    1998-06-01

    Identification of anatomical structures in magnetic resonance (MR) images of the human brain is achieved either by manual delineation of by applying coordinate system transformations to map the brain to a pre-labeled atlas. Manual segmentation of 3D MR data is a tedious task made additionally difficult by limitations in visualization. Affine transforms, like the Talairach stereotaxic space, perform a linear scaling of the brain based on manually selected landmarks. This often results in unsatisfactory accuracy for structures further away from the selected landmarks, particularly in pathological cases. It is also based on the trivializing assumption that the brain can be represented as a linearly scalable structure. In the effort to achieve a more accurate and consistent labeling, an algorithm has been designed for the automated alignment of a pre-labeled 3D brain atlas with a sample MRI volume. Alignment is achieved by elastically warping a finite element model of the atlas. The deformation is driven by a set of displacement constraints on the surface of individual brain structures. Solving this model results in a 3D displacement field for the entire atlas brain that aligns the segmented brain structure while extrapolating the deformation field to neighboring structures. The use of finite element modeling assures that this extrapolation occurs in a physically meaningful manner. The algorithm's performance was tested by matching the atlas image to warped versions of itself and to an individual sample brain. The amount of structural overlap achieved by a linear Talairach transform is also given for comparison. Elastic warping showed better performance compared to an affine transform alone or the Talairach method. Overlap increases with subsequent iterations with improvement directly related to the amount of model deformation.

  6. Anatomical study of spinal accessory nerve using ultrasonography

    Energy Technology Data Exchange (ETDEWEB)

    Canella, Clarissa [Service de Radiologie et d’Imagerie Musculosquelettique, Centre de Consultations et d’Imagerie de l’Appareil Locomoteur, CHRU, 59037, Lille (France); Serviço de Radiologia e Diagnostico por Imagem, Universitadade Federal do Rio de Janeiro, Rio de janeiro (Brazil); Demondion, Xavier [Service de Radiologie et d’Imagerie Musculosquelettique, Centre de Consultations et d’Imagerie de l’Appareil Locomoteur, CHRU, 59037, Lille (France); Laboratoire d’Anatomie, Faculté de Médecine de Lille, 59037, Lille (France); Abreu, Evandro [Service de Radiologie et d’Imagerie Musculosquelettique, Centre de Consultations et d’Imagerie de l’Appareil Locomoteur, CHRU, 59037, Lille (France); Marchiori, Edson [Serviço de Radiologia e Diagnostico por Imagem, Universitadade Federal do Rio de Janeiro, Rio de janeiro (Brazil); Cotten, Hervé [Anatomie et cytologie pathologiques, Bd de la Liberté, 59000, Lille (France); Cotten, Anne, E-mail: anne.cotten@chru-lille.fr [Service de Radiologie et d’Imagerie Musculosquelettique, Centre de Consultations et d’Imagerie de l’Appareil Locomoteur, CHRU, 59037, Lille (France)

    2013-01-15

    Objective: The purpose of our study was to demonstrate that ultrasonography may allow a precise assessment of the course and relationships of the spinal accessory nerve (SAN). Material and methods: This study, initially undertaken in 7 cadavers, was followed by high-resolution ultrasonographic study in 15 volunteers (30 nerves) by two radiologists in consensus. The location, course and relations to the adjacent anatomic structures of the SAN were analyzed. Results: The precise course of the SAN between the lateroposterior border of the sternocleidomastoid muscle and the anterior border of the trapezius muscle could be identified by high-resolution ultrasonography. In contrast, clinical bone landmarks were not found helpful for the identification of the nerve. Conclusion: The SAN can be clearly depicted by means of ultrasonography. Knowledge of the nerve's precise location, which may evidence individual variations, may have useful clinical applications.

  7. Anatomical study of spinal accessory nerve using ultrasonography

    International Nuclear Information System (INIS)

    Objective: The purpose of our study was to demonstrate that ultrasonography may allow a precise assessment of the course and relationships of the spinal accessory nerve (SAN). Material and methods: This study, initially undertaken in 7 cadavers, was followed by high-resolution ultrasonographic study in 15 volunteers (30 nerves) by two radiologists in consensus. The location, course and relations to the adjacent anatomic structures of the SAN were analyzed. Results: The precise course of the SAN between the lateroposterior border of the sternocleidomastoid muscle and the anterior border of the trapezius muscle could be identified by high-resolution ultrasonography. In contrast, clinical bone landmarks were not found helpful for the identification of the nerve. Conclusion: The SAN can be clearly depicted by means of ultrasonography. Knowledge of the nerve's precise location, which may evidence individual variations, may have useful clinical applications

  8. Improving anatomical mapping of complexly deformed anatomy for external beam radiotherapy and brachytherapy dose accumulation in cervical cancer

    International Nuclear Information System (INIS)

    Purpose: In the treatment of cervical cancer, large anatomical deformations, caused by, e.g., tumor shrinkage, bladder and rectum filling changes, organ sliding, and the presence of the brachytherapy (BT) applicator, prohibit the accumulation of external beam radiotherapy (EBRT) and BT dose distributions. This work proposes a structure-wise registration with vector field integration (SW+VF) to map the largely deformed anatomies between EBRT and BT, paving the way for 3D dose accumulation between EBRT and BT. Methods: T2w-MRIs acquired before EBRT and as a part of the MRI-guided BT procedure for 12 cervical cancer patients, along with the manual delineations of the bladder, cervix-uterus, and rectum-sigmoid, were used for this study. A rigid transformation was used to align the bony anatomy in the MRIs. The proposed SW+VF method starts by automatically segmenting features in the area surrounding the delineated organs. Then, each organ and feature pair is registered independently using a feature-based nonrigid registration algorithm developed in-house. Additionally, a background transformation is calculated to account for areas far from all organs and features. In order to obtain one transformation that can be used for dose accumulation, the organ-based, feature-based, and the background transformations are combined into one vector field using a weighted sum, where the contribution of each transformation can be directly controlled by its extent of influence (scope size). The optimal scope sizes for organ-based and feature-based transformations were found by an exhaustive analysis. The anatomical correctness of the mapping was independently validated by measuring the residual distances after transformation for delineated structures inside the cervix-uterus (inner anatomical correctness), and for anatomical landmarks outside the organs in the surrounding region (outer anatomical correctness). The results of the proposed method were compared with the results of the rigid transformation and nonrigid registration of all structures together (AST). Results: The rigid transformation achieved a good global alignment (mean outer anatomical correctness of 4.3 mm) but failed to align the deformed organs (mean inner anatomical correctness of 22.4 mm). Conversely, the AST registration produced a reasonable alignment for the organs (6.3 mm) but not for the surrounding region (16.9 mm). SW+VF registration achieved the best results for both regions (3.5 and 3.4 mm for the inner and outer anatomical correctness, respectively). All differences were significant (p < 0.02, Wilcoxon rank sum test). Additionally, optimization of the scope sizes determined that the method was robust for a large range of scope size values. Conclusions: The novel SW+VF method improved the mapping of large and complex deformations observed between EBRT and BT for cervical cancer patients. Future studies that quantify the mapping error in terms of dose errors are required to test the clinical applicability of dose accumulation by the SW+VF method

  9. Improving anatomical mapping of complexly deformed anatomy for external beam radiotherapy and brachytherapy dose accumulation in cervical cancer

    Energy Technology Data Exchange (ETDEWEB)

    Vásquez Osorio, Eliana M., E-mail: e.vasquezosorio@erasmusmc.nl; Kolkman-Deurloo, Inger-Karine K.; Schuring-Pereira, Monica; Zolnay, András; Heijmen, Ben J. M.; Hoogeman, Mischa S. [Department of Radiation Oncology, Erasmus MC Cancer Institute, Rotterdam 3075 (Netherlands)

    2015-01-15

    Purpose: In the treatment of cervical cancer, large anatomical deformations, caused by, e.g., tumor shrinkage, bladder and rectum filling changes, organ sliding, and the presence of the brachytherapy (BT) applicator, prohibit the accumulation of external beam radiotherapy (EBRT) and BT dose distributions. This work proposes a structure-wise registration with vector field integration (SW+VF) to map the largely deformed anatomies between EBRT and BT, paving the way for 3D dose accumulation between EBRT and BT. Methods: T2w-MRIs acquired before EBRT and as a part of the MRI-guided BT procedure for 12 cervical cancer patients, along with the manual delineations of the bladder, cervix-uterus, and rectum-sigmoid, were used for this study. A rigid transformation was used to align the bony anatomy in the MRIs. The proposed SW+VF method starts by automatically segmenting features in the area surrounding the delineated organs. Then, each organ and feature pair is registered independently using a feature-based nonrigid registration algorithm developed in-house. Additionally, a background transformation is calculated to account for areas far from all organs and features. In order to obtain one transformation that can be used for dose accumulation, the organ-based, feature-based, and the background transformations are combined into one vector field using a weighted sum, where the contribution of each transformation can be directly controlled by its extent of influence (scope size). The optimal scope sizes for organ-based and feature-based transformations were found by an exhaustive analysis. The anatomical correctness of the mapping was independently validated by measuring the residual distances after transformation for delineated structures inside the cervix-uterus (inner anatomical correctness), and for anatomical landmarks outside the organs in the surrounding region (outer anatomical correctness). The results of the proposed method were compared with the results of the rigid transformation and nonrigid registration of all structures together (AST). Results: The rigid transformation achieved a good global alignment (mean outer anatomical correctness of 4.3 mm) but failed to align the deformed organs (mean inner anatomical correctness of 22.4 mm). Conversely, the AST registration produced a reasonable alignment for the organs (6.3 mm) but not for the surrounding region (16.9 mm). SW+VF registration achieved the best results for both regions (3.5 and 3.4 mm for the inner and outer anatomical correctness, respectively). All differences were significant (p < 0.02, Wilcoxon rank sum test). Additionally, optimization of the scope sizes determined that the method was robust for a large range of scope size values. Conclusions: The novel SW+VF method improved the mapping of large and complex deformations observed between EBRT and BT for cervical cancer patients. Future studies that quantify the mapping error in terms of dose errors are required to test the clinical applicability of dose accumulation by the SW+VF method.

  10. Necessity Of Anatomical Knowledge In Thoracic Surgery.

    Directory of Open Access Journals (Sweden)

    Arribalzaga, Eduardo B.

    2011-09-01

    Full Text Available The necessity of anatomical knowledge was fundamental issue for medical practice since prehistoric times and with the passing of centuries, that knowledge was improved very slowly. So in mid-1535 Vesalius began to study the human body by dissecting cadavers and warned that the dissection was the most important means by direct observation as the only reliable source. Through his work set aside age-old classic mistakes to discover that Galen's investigations were based on the dissection of animals, not of humans. His contemporary highlighted the anatomical knowledge as essential to the practice of surgery, shared this view with Vesalius. He was the initiator of the regional anatomy describing topographic anatomical areas and regional levels. Through the centuries, the anatomical knowledge was updated to facilitate the incorporation of techniques and technologies that emerged every day. Alejandro Posadas in Argentina who opened the thoracic surgery endocavitary insisted on a clear notion of the thoracic anatomy to aid in surgical practice. Later Avelino Gutierrez and Eugenio A. Galli highlighted a reasoned interpretation and a new nomenclature for the cardiac chambers according to their topographic reality. Jose Luis Martinez finally gave a distinctive character to Argentinian thoracic surgery by highlighting a detailed anatomical knowledge and begin to dissect the pulmonary hilum neglecting mass ligation of the pedicle. The acquisition of new Biostructural knowledge allows therapeutic approaches by new routes such as video-assisted surgical procedures and new diagnostic imaging such as magnetic resonance angiography. There is talk of a new disease for lack of anatomical basics notions. Its integration with the semiologic knowledges allows the combination of the basic notions that provide adequate medical care.

  11. Standardized anatomic space for abdominal fat quantification

    Science.gov (United States)

    Tong, Yubing; Udupa, Jayaram K.; Torigian, Drew A.

    2014-03-01

    The ability to accurately measure subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) from images is important for improved assessment and management of patients with various conditions such as obesity, diabetes mellitus, obstructive sleep apnea, cardiovascular disease, kidney disease, and degenerative disease. Although imaging and analysis methods to measure the volume of these tissue components have been developed [1, 2], in clinical practice, an estimate of the amount of fat is obtained from just one transverse abdominal CT slice typically acquired at the level of the L4-L5 vertebrae for various reasons including decreased radiation exposure and cost [3-5]. It is generally assumed that such an estimate reliably depicts the burden of fat in the body. This paper sets out to answer two questions related to this issue which have not been addressed in the literature. How does one ensure that the slices used for correlation calculation from different subjects are at the same anatomic location? At what anatomic location do the volumes of SAT and VAT correlate maximally with the corresponding single-slice area measures? To answer these questions, we propose two approaches for slice localization: linear mapping and non-linear mapping which is a novel learning based strategy for mapping slice locations to a standardized anatomic space so that same anatomic slice locations are identified in different subjects. We then study the volume-to-area correlations and determine where they become maximal. We demonstrate on 50 abdominal CT data sets that this mapping achieves significantly improved consistency of anatomic localization compared to current practice. Our results also indicate that maximum correlations are achieved at different anatomic locations for SAT and VAT which are both different from the L4-L5 junction commonly utilized.

  12. What Factors Shape "by" Ratings in Relation to Landmarks?

    Science.gov (United States)

    Hund, Alycia M.

    2010-01-01

    Two experiments investigated how absolute and relative distance shape adults' and young children's ratings concerning the extent to which the term "by" describes the relation between locations. Three- and 4-year-old children and adults were asked to rate how well the word "by" described the relation between several blocks and a landmark. The…

  13. 36 CFR 62.5 - Natural landmark criteria.

    Science.gov (United States)

    2010-07-01

    ... a specific type of natural feature are the main basis for selection and are described in the... history; and fossil evidence of biological evolution. Because the general character of natural diversity... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Natural landmark criteria....

  14. An Adaptive Algorithm for Finding Frequent Sets in Landmark Windows

    DEFF Research Database (Denmark)

    Dang, Xuan-Hong; Ong, Kok-Leong; Lee, Vincent

    2012-01-01

    We consider a CPU constrained environment for finding approximation of frequent sets in data streams using the landmark window. Our algorithm can detect overload situations, i.e., breaching the CPU capacity, and sheds data in the stream to “keep up”. This is done within a controlled error threshold by exploiting the Chernoff-bound. Empirical evaluation of the algorithm confirms the feasibility.

  15. The Landmark Decision that Faded into Historical Obscurity

    Science.gov (United States)

    Nance, Molly

    2007-01-01

    This article takes a look at the Mendez v. Westminster School District, a landmark case that faded into historical obscurity. In the 1940s, Gonzalo and Felicita Mendez wanted their three children to attend the school nearest their farm, which was the 17th Street Elementary School in Westminster. But in the Westminster, Orange County, El Medina,…

  16. On-line SLAM using clustered landmarks with omnidirectional vision

    Scientific Electronic Library Online (English)

    Jun, Okamoto Jr.; Vitor Campanholo, Guizilini.

    2010-12-01

    Full Text Available The problem of SLAM (simultaneous localization and mapping) is a fundamental problem in autonomous robotics. It arises when a robot must create a map of the regions it has navigated while localizing itself on it, using results from one step to increase precision in another by eliminating errors inhe [...] rent to the sensors. One common solution consists of establishing landmarks in the environment which are used as reference points for absolute localization estimates and form a sparse map that is iteratively refined as more information is obtained. This paper introduces a method of landmark selection and clustering in omnidirectional images for on-line SLAM, using the SIFT algorithm for initial feature extraction and assuming no prior knowledge of the environment. Visual sensors are an attractive way of collecting information from the environment, but tend to create an excessive amount of landmarks that are individually prone to false matches due to image noise and object similarities. By clustering several features in single objects, our approach eliminates landmarks that do not consistently represent the environment, decreasing computational cost and increasing the reliability of information incorporated. Tests conducted in real navigational situations show a significant improvement in performance without loss of quality.

  17. Landmark NIH Study Shows Intensive Blood Pressure Management May Save Lives

    Science.gov (United States)

    ... News Releases News Release Friday, September 11, 2015 Landmark NIH study shows intensive blood pressure management may ... is according to the initial results of a landmark clinical trial sponsored by the National Institutes of ...

  18. Slice-based supine-to-standing posture deformation for chinese anatomical models and the dosimetric results with wide band frequency electromagnetic field exposure: Simulation

    International Nuclear Information System (INIS)

    Standing Chinese adult anatomical models are obtained from supine-postured cadaver slices. This paper presents the dosimetric differences between the supine and the standing postures over wide band frequencies and various incident configurations. Both the body level and the tissue/organ level differences are reported for plane wave and the 3T magnetic resonance imaging radiofrequency electromagnetic field exposure. The influence of posture on the whole body specific absorption rate and tissue specified specific absorption rate values is discussed. . (authors)

  19. IAEA Director General welcomes landmark convention to combat nuclear terrorism

    International Nuclear Information System (INIS)

    Full text: IAEA Director General Mohamed ElBaradei welcomed the adoption of an International convention against nuclear terrorism. 'This is a landmark achievement which will bolster global efforts to combat nuclear terrorism,' Dr. ElBaradei said. 'It will be a key part of international efforts to prevent terrorists from gaining access to nuclear weapons'. The United Nations General Assembly adopted the convention, The International Convention for the Suppression of Acts of Nuclear Terrorism, on 13 April 2005. The Convention strengthens the global legal framework to counter terrorist threats. Based on a proposal by the Russian Federation in 1998, the Convention focuses on criminal offences related to nuclear terrorism and covers a broad range of possible targets, including nuclear reactors as well as nuclear material and radioactive substances. Under its provisions, alleged offenders - for example any individual or group that unlawfully and intentionally possesses or uses radioactive material with the intent to cause harm - must be either extradited or prosecuted. States are also encouraged to cooperate with each other in connection with criminal investigations and extradition proceedings. The Convention further requires that any seized nuclear or radiological material be held in accordance with IAEA safeguards, and handled in keeping with the IAEA's health, safety and physical protection standards. Dr. ElBaradei also recalled that the Agency is in the process of amending the Convention on the Physical Protection of Nuclear Material, in order to broaden its scope, and in so doing, strengthen the current legal framework for securing nuclear material against illicit uses. A conference will be held from 4 to 8 July in Vienna to consider and adopt the amendments. The Convention opens for signature in September this year. Dr ElBaradei urged all States to 'sign and ratify the Convention without delay so nuclear terrorism will have no chance'. (IAEA)

  20. Learned predictiveness training modulates biases towards using boundary or landmark cues during navigation

    OpenAIRE

    Buckley, Matthew G.; Smith, Alastair D; Haselgrove, Mark

    2014-01-01

    A number of navigational theories state that learning about landmark information should not interfere with learning about shape information provided by the boundary walls of an environment. A common test of such theories has been to assess whether landmark information will overshadow, or restrict, learning about shape information. Whilst a number of studies have shown that landmarks are not able to overshadow learning about shape information, some have shown that landmarks can, in fact, overs...

  1. A field study investigating effects of landmarks on territory size and shape

    OpenAIRE

    Suriyampola, Piyumika S.; Eason, Perri K.

    2014-01-01

    Few studies have examined how landmarks affect territories' fundamental characteristics. In this field study, we investigated effects of landmarks on territory size, shape and location in a cichlid fish (Amatitlania siquia). We provided cans as breeding sites and used plastic plants as landmarks. During 10 min trials, we recorded locations where residents chased intruders and used those locations to outline and measure the territory. In two experiments, we observed pairs without landmarks and...

  2. Landmarks or panoramas: what do navigating ants attend to for guidance?

    OpenAIRE

    Beugnon Guy; Wystrach Antoine; Cheng Ken

    2011-01-01

    Abstract Background Insects are known to rely on terrestrial landmarks for navigation. Landmarks are used to chart a route or pinpoint a goal. The distant panorama, however, is often thought not to guide navigation directly during a familiar journey, but to act as a contextual cue that primes the correct memory of the landmarks. Results We provided Melophorus bagoti ants with a huge artificial landmark located right near the nest entrance to find out whether navigating ants focus on such a pr...

  3. Information geometry for landmark shape analysis: unifying shape representation and deformation.

    Science.gov (United States)

    Peter, Adrian M; Rangarajan, Anand

    2009-02-01

    Shape matching plays a prominent role in the comparison of similar structures. We present a unifying framework for shape matching that uses mixture models to couple both the shape representation and deformation. The theoretical foundation is drawn from information geometry wherein information matrices are used to establish intrinsic distances between parametric densities. When a parameterized probability density function is used to represent a landmark-based shape, the modes of deformation are automatically established through the information matrix of the density. We first show that given two shapes parameterized by Gaussian mixture models (GMMs), the well-known Fisher information matrix of the mixture model is also a Riemannian metric (actually, the Fisher-Rao Riemannian metric) and can therefore be used for computing shape geodesics. The Fisher-Rao metric has the advantage of being an intrinsic metric and invariant to reparameterization. The geodesicâcomputed using this metricâestablishes an intrinsic deformation between the shapes, thus unifying both shape representation and deformation. A fundamental drawback of the Fisher-Rao metric is that it is not available in closed form for the GMM. Consequently, shape comparisons are computationally very expensive. To address this, we develop a new Riemannian metric based on generalized \\phi-entropy measures. In sharp contrast to the Fisher-Rao metric, the new metric is available in closed form. Geodesic computations using the new metric are considerably more efficient. We validate the performance and discriminative capabilities of these new information geometry-based metrics by pairwise matching of corpus callosum shapes. We also study the deformations of fish shapes that have various topological properties. A comprehensive comparative analysis is also provided using other landmark-based distances, including the Hausdorff distance, the Procrustes metric, landmark-based diffeomorphisms, and the bending energies of the thin-plate (TPS) and Wendland splines. PMID:19110497

  4. Developmental Changes in Young Children's Spatial Memory and Language in Relation to Landmarks

    Science.gov (United States)

    Hund, Alycia M.; Naroleski, Amber R.

    2008-01-01

    Two experiments investigated how young children and adults understand whether objects are "by" a landmark and remember their locations. Three- and 4-year-old children and adults were asked to judge whether several blocks were "by" a landmark. The blocks were arranged so that their absolute and relative distances from the landmark varied. Later,…

  5. 76 FR 55701 - Landmarks Committee of the National Park System Advisory Board Meeting

    Science.gov (United States)

    2011-09-08

    ... National Park Service Landmarks Committee of the National Park System Advisory Board Meeting AGENCY... Federal Advisory Committee Act , that a meeting of the Landmarks Committee of the National Park System... Landmarks Program, National Park Service; 1849 C Street, NW., (2280), Washington, DC 20240; Telephone...

  6. 76 FR 60079 - Landmarks Committee of the National Park System Advisory Board Meeting

    Science.gov (United States)

    2011-09-28

    ... National Park Service Landmarks Committee of the National Park System Advisory Board Meeting AGENCY... Federal Advisory Committee Act , that a meeting of the Landmarks Committee of the National Park System... Landmarks Program, National Park Service; 1849 C Street, NW., (2280); Washington, DC 20240; Telephone...

  7. 36 CFR 65.8 - Alteration of National Historic Landmark boundaries.

    Science.gov (United States)

    2010-07-01

    ... Historic Landmark boundaries. 65.8 Section 65.8 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL HISTORIC LANDMARKS PROGRAM § 65.8 Alteration of National Historic Landmark boundaries. (a) Two justifications exist for enlarging the boundary of a National...

  8. 36 CFR 800.10 - Special requirements for protecting National Historic Landmarks.

    Science.gov (United States)

    2010-07-01

    ... protecting National Historic Landmarks. 800.10 Section 800.10 Parks, Forests, and Public Property ADVISORY... Special requirements for protecting National Historic Landmarks. (a) Statutory requirement. Section 110(f... and actions as may be necessary to minimize harm to any National Historic Landmark that may...

  9. 78 FR 13377 - Landmarks Committee of the National Park System Advisory Board Meeting

    Science.gov (United States)

    2013-02-27

    ... National Park Service Landmarks Committee of the National Park System Advisory Board Meeting AGENCY... Landmarks Committee of the National Park System Advisory Board will be held beginning at 1:00 p.m. on April... National Park System Advisory Board and its Landmarks Committee may consider the following...

  10. 76 FR 15338 - Landmarks Committee of the National Park System Advisory Board Meeting

    Science.gov (United States)

    2011-03-21

    ... National Park Service Landmarks Committee of the National Park System Advisory Board Meeting AGENCY... with the Federal Advisory Committee Act , that a meeting of the Landmarks Committee of the National... Henry, National Historic Landmarks Program, National Park Service; 1849 C Street, NW. (2280);...

  11. 77 FR 44670 - Information Collection Activities: National Historic Landmarks (NHL) Condition Survey

    Science.gov (United States)

    2012-07-30

    ... National Park Service Information Collection Activities: National Historic Landmarks (NHL) Condition Survey....gov (email). Please reference Information Collection 1024-NEW, National Historic Landmarks (NHL... Historic Landmarks Program, 1201 Eye St. NW., Washington, DC 20005. You may send an email to...

  12. 77 FR 53230 - Landmarks Committee of the National Park System Advisory Board Meeting

    Science.gov (United States)

    2012-08-31

    ... National Park Service Landmarks Committee of the National Park System Advisory Board Meeting AGENCY... with the Federal Advisory Committee Act, 5 U.S.C. Appendix (1988), that a meeting of the Landmarks... Park System Advisory Board and its Landmarks Committee may consider the following nominations:...

  13. Solving small spaces: investigating the use of landmark cues in brown capuchins (Cebus apella).

    Science.gov (United States)

    Hughes, Kelly D; Mullo, Enma; Santos, Laurie R

    2013-09-01

    Some researchers have recently argued that humans may be unusual among primates in preferring to use landmark information when reasoning about some kinds of spatial problems. Some have explained this phenomenon by positing that our species' tendency to prefer landmarks stems from a human-unique trait: language. Here, we test this hypothesis-that preferring to use landmarks to solve such tasks is related to language ability-by exploring landmark use in a spatial task in one non-human primate, the brown capuchin monkey (Cebus apella). We presented our subjects with the rotational displacement task, in which subjects attempt to relocate a reward hidden within an array of hiding locations which are subsequently rotated to a new position. Over several experiments, we varied the availability and the salience of a landmark cue within the array. Specifically, we varied (1) visual access to the array during rotation, (2) the type of landmark, (3) the consistency of the landmark qualities, and (4) the amount of exposure to the landmark. Across Experiments 1 through 4, capuchins did not successfully use landmarks cues, suggesting that non-linguistic primates may not spontaneously use landmarks to solve some spatial problems, as in this case of a small-scale dynamic spatial task. Importantly, we also observed that capuchins demonstrated some capacity to learn to use landmarks in Experiment 4, suggesting that non-linguistic creatures may be able to use some landmarks cues in similar spatial tasks with extensive training. PMID:23430144

  14. Cephalometric landmark variability among orthodontists and dentomaxillofacial radiologists: a comparative study

    Science.gov (United States)

    Morosolli, Aline; Pittayapat, Pisha; Bolstad, Napat; Ferreira, Afonso P.; Jacobs, Reinhilde

    2015-01-01

    Purpose The aim this study was to compare the accuracy of orthodontists and dentomaxillofacial radiologists in identifying 17 commonly used cephalometric landmarks, and to determine the extent of variability associated with each of those landmarks. Materials and Methods Twenty digital lateral cephalometric radiographs were evaluated by two groups of dental specialists, and 17 cephalometric landmarks were identified. The x and y coordinates of each landmark were recorded. The mean value for each landmark was considered the best estimate and used as the standard. Variation in measurements of the distance between landmarks and measurements of the angles associated with certain landmarks was also assessed by a subset of two observers, and intraobserver and interobserver agreement were evaluated. Results Intraclass correlation coefficients were excellent for intraobserver agreement, but only good for interobserver agreement. The least reliable landmark for orthodontists was the gnathion (Gn) point (standard deviation [SD], 5.92 mm), while the orbitale (Or) was the least reliable landmark (SD, 4.41 mm) for dentomaxillofacial radiologists. Furthermore, the condylion (Co)-Gn plane was the least consistent (SD, 4.43 mm). Conclusion We established that some landmarks were not as reproducible as others, both horizontally and vertically. The most consistently identified landmark in both groups was the lower incisor border, while the least reliable points were Co, Gn, Or, and the anterior nasal spine. Overall, a lower level of reproducibility in the identification of cephalometric landmarks was observed among orthodontists. PMID:26730368

  15. Importance of the node of Calot in gallbladder neck dissection: an important landmark in the standardized approach to the laparoscopic cholecystectomy.

    Science.gov (United States)

    Ferzli, George; Timoney, Michael; Nazir, Sharique; Swedler, David; Fingerhut, Abe

    2015-01-01

    The current rate of bile duct injury (BDI) after laparoscopic cholecystectomy is 0.4%, which is an unacceptable outcome. Several surgical approaches have been suggested to mitigate the occurrence of this dreaded complication. We propose a standardized approach, using Calot's node as a critical anatomical landmark to guide gallbladder dissection and avoid BDI. We retrospectively analyzed a prospectively gathered database of 907 laparoscopic cholecystectomies using this standardized approach in our practice over a 5-year period. To date we have had no BDI and no cystic duct leak. Therefore, we suggest identification of Calot's node as an additional method to avoid BDI during laparoscopic cholecystectomy. PMID:25559890

  16. MR neurography with multiplanar reconstruction of 3D MRI datasets: an anatomical study and clinical applications

    Energy Technology Data Exchange (ETDEWEB)

    Freund, Wolfgang; Aschoff, Andrik J.; Stuber, Gregor; Schmitz, Bernd [University Hospitals Ulm, Clinic for Diagnostic and Interventional Radiology, Ulm (Germany); Brinkmann, Alexander; Wagner, Florian; Dinse, Alexander [University Hospitals Ulm, Department of Anesthesiology, Ulm (Germany)

    2007-04-15

    Extracranial MR neurography has so far mainly been used with 2D datasets. We investigated the use of 3D datasets for peripheral neurography of the sciatic nerve. A total of 40 thighs (20 healthy volunteers) were examined with a coronally oriented magnetization-prepared rapid acquisition gradient echo sequence with isotropic voxels of 1 x 1 x 1 mm and a field of view of 500 mm. Anatomical landmarks were palpated and marked with MRI markers. After MR scanning, the sciatic nerve was identified by two readers independently in the resulting 3D dataset. In every volunteer, the sciatic nerve could be identified bilaterally over the whole length of the thigh, even in areas of close contact to isointense muscles. The landmark of the greater trochanter was falsely palpated by 2.2 cm, and the knee joint by 1 cm. The mean distance between the bifurcation of the sciatic nerve and the knee-joint gap was 6 cm ({+-}1.8 cm). The mean results of the two readers differed by 1-6%. With the described method of MR neurography, the sciatic nerve was depicted reliably and objectively in great anatomical detail over the whole length of the thigh. Important anatomical information can be obtained. The clinical applications of MR neurography for the brachial plexus and lumbosacral plexus/sciatic nerve are discussed. (orig.)

  17. MR neurography with multiplanar reconstruction of 3D MRI datasets: an anatomical study and clinical applications

    International Nuclear Information System (INIS)

    Extracranial MR neurography has so far mainly been used with 2D datasets. We investigated the use of 3D datasets for peripheral neurography of the sciatic nerve. A total of 40 thighs (20 healthy volunteers) were examined with a coronally oriented magnetization-prepared rapid acquisition gradient echo sequence with isotropic voxels of 1 x 1 x 1 mm and a field of view of 500 mm. Anatomical landmarks were palpated and marked with MRI markers. After MR scanning, the sciatic nerve was identified by two readers independently in the resulting 3D dataset. In every volunteer, the sciatic nerve could be identified bilaterally over the whole length of the thigh, even in areas of close contact to isointense muscles. The landmark of the greater trochanter was falsely palpated by 2.2 cm, and the knee joint by 1 cm. The mean distance between the bifurcation of the sciatic nerve and the knee-joint gap was 6 cm (±1.8 cm). The mean results of the two readers differed by 1-6%. With the described method of MR neurography, the sciatic nerve was depicted reliably and objectively in great anatomical detail over the whole length of the thigh. Important anatomical information can be obtained. The clinical applications of MR neurography for the brachial plexus and lumbosacral plexus/sciatic nerve are discussed. (orig.)

  18. The avascular plane of the Achilles tendon: A quantitative anatomic and angiographic approach and a base for a possible new treatment option after rupture

    International Nuclear Information System (INIS)

    Introduction: Achilles tendon ruptures, especially ruptures caused by pathologic conditions and also by achillotendinitis are often attributed to the alleged hypovascularisation of the Achilles tendon. Anatomic studies often mention an avascular plane. The purpose of this study was to re-investigate the arterial supply of the Achilles tendon. Material and methods: Lower legs of 28 anatomic specimen were injected with a radiologic contrast agent and subsequently an arterial angiography was performed. Afterwards the legs were embalmed and later anatomically dissected. The origin of arteries entering the paratenon of the tendo calcanei branching off from either the anterior (TA) or the posterior tibial artery (TP) was determined. The distance between the points of commencement of these nutrient arteries and a specific reference point, i.e. the insertion of the Achilles tendon into the tuber calcanei, was measured digitally on the radiographs and again with a slide-gauge on the dissected specimens. Results: As revealed by angiographic analysis, the TA gave off 5 vessels (v) at a frequency and median distance to the tuber calcanei (in cm) of v1: 50%, 6.01 cm; v2: 39.3%, 7.88 cm; v3: 35.7%, 9.71 cm; v4: 17.9%, 12.7 cm; v5: 10.7%, 14.6 cm. The TP contributed to the arterial supply of the Achilles tendon by means of 7 inserting arteries branching off at a frequency and mean distances of v1: 67.9%, 4.53 cm; v2: 60.7%, 6.97 cm, v3: 50%, 9.58 cm; v4: 35.7%, 10.89 cm; v5: 25%, 12.65 cm; v6: 10.7%, 16.94 cm; v7: 3.6%, 18.7 cm proximal to the tuber calcanei. However, due to the small diameter of these branches, by anatomic dissection no nutrient arteries commencing from the TA could be detected. On the other hand, a maximum of 7 vessels originating from the TP, larger than the former vessels, had been also revealed by anatomic dissection (frequency and mean distances, v1: 100%, 6.8 cm; v2: 82.1%, 7.7 cm; v3: 71.4%, 9.5 cm; v4: 35.7%, 11.3 cm; v5: 17.9%, 9.9 cm; v6: 7.1, 10.5 cm; v7: 3.6%, 12.0 cm). Conclusion: A dense net of small arteries inserts into the paratenon of the Achilles tendon in its lower 20 cm. The angiographic method was more specific and showed vessels that could not be identified as arteries originating from the TA by macroscopic anatomic dissection.

  19. Correction of dental artifacts within the anatomical surface in PET/MRI using Active Shape Models and k-Nearest-Neighbors

    DEFF Research Database (Denmark)

    Ladefoged, Claes N.; Andersen, Flemming L.; Keller, Sune H.; Beyer, Thomas; Højgaard, Liselotte; Lauze, Francois Bernard

    2014-01-01

    anatomy. ASM is used to locate a number of landmarks in the T1-weighted MR-image of a new patient. We calculate a vector of offsets from each voxel within a signal void to each of the landmarks. We then use kNN to classify each voxel as belonging to an artifact or an actual signal void using this offset...... vector, and fill the artifact voxels with a value representing soft tissue. We tested the method using fourteen patients without artifacts, and eighteen patients with dental artifacts of varying sizes within the anatomical surface of the head/neck region. Though the method wrongly filled a small volume...

  20. Spinal cord localization in the treatment of lung cancer: use of radiographic landmarks

    International Nuclear Information System (INIS)

    Purpose: In the treatment of thoracic malignancies with radiotherapy, the critical dose-limiting structure is the spinal cord. Oblique fields typically are designed to exclude the spinal cord, and by convention, the field edge that shields the spinal cord is placed at the anterior border of the vertebral pedicles. Thus, the purpose of our study was to estimate the distance between the field edge and spinal cord in oblique fields that were designed by using the vertebral pedicle as a radiographic landmark. Methods and Materials: The spinal cord of a cadaver was wrapped in wire, and oblique fields were simulated at 15 deg. intervals. The distance from the spinal cord to a field edge placed at the anterior border of the pedicle was measured. In the second investigation, a three-dimensional treatment planning system was used to simulate hypothetical fields using actual patient data from computed tomography (n = 10), and measurements identical to those in the anatomical model were made (n = 1,100). Results: The results of the anatomical and computed tomographic models were in close agreement (mean difference, 0.6 mm). The computed tomographic model predicted a mean field edge to spinal cord distance of 8.7 mm (95% confidence interval, 5.6-11.8 mm) for (30 deg. (150 deg.)) oblique fields and 8.0 mm (95% confidence interval, 4.7-11.7 mm) for (45 deg. (135 deg.)) oblique fields. This distance was greatest at levels T-1, T-2, and T-11 (8 to 20% greater). Conclusions: The mean distance from a field edge placed at the anterior border of a vertebral pedicle to the spinal cord for commonly used oblique angles constitutes a sufficient margin to account for expected differences in daily positional variations and mechanical uncertainties

  1. PET image reconstruction with anatomical edge guided level set prior

    Science.gov (United States)

    Cheng-Liao, Jinxiu; Qi, Jinyi

    2011-11-01

    Acquiring both anatomical and functional images during one scan, PET/CT systems improve the ability to detect and localize abnormal uptakes. In addition, CT images provide anatomical boundary information that can be used to regularize positron emission tomography (PET) images. Here we propose a new approach to maximum a posteriori reconstruction of PET images with a level set prior guided by anatomical edges. The image prior models both the smoothness of PET images and the similarity between functional boundaries in PET and anatomical boundaries in CT. Level set functions (LSFs) are used to represent smooth and closed functional boundaries. The proposed method does not assume an exact match between PET and CT boundaries. Instead, it encourages similarity between the two boundaries, while allowing different region definition in PET images to accommodate possible signal and position mismatch between functional and anatomical images. While the functional boundaries are guaranteed to be closed by the LSFs, the proposed method does not require closed anatomical boundaries and can utilize incomplete edges obtained from an automatic edge detection algorithm. We conducted computer simulations to evaluate the performance of the proposed method. Two digital phantoms were constructed based on the Digimouse data and a human CT image, respectively. Anatomical edges were extracted automatically from the CT images. Tumors were simulated in the PET phantoms with different mismatched anatomical boundaries. Compared with existing methods, the new method achieved better bias-variance performance. The proposed method was also applied to real mouse data and achieved higher contrast than other methods.

  2. Undecidability and temporal logic: some landmarks from Turing to the present

    DEFF Research Database (Denmark)

    Goranko, Valentin

    2012-01-01

    This is a selective survey and discussion of some of the landmark undecidability results in temporal logic, beginning with Turing's undecidability of the Halting problem which, in retrospect, can be regarded as the historically first undecidability result for a suitable temporal logic over configuration graphs of Turing machines. I will discuss some of the natural habitats of undecidable temporal logics, such as first-order, interval-based and real time temporal logics, as well as some extensions that often lead to undecidability, such as two-dimensional temporal logics and temporal-epistemic logics.

  3. Patterns of Care - SEER Landmark Studies

    Science.gov (United States)

    SEER is an authoritative source of information on cancer incidence and survival in the United States. SEER currently collects and publishes cancer incidence and survival data from population-based cancer registries covering approximately 28 percent of the U.S. population.

  4. Health Policy: Colorectal Cancer - SEER Landmark Studies

    Science.gov (United States)

    SEER is an authoritative source of information on cancer incidence and survival in the United States. SEER currently collects and publishes cancer incidence and survival data from population-based cancer registries covering approximately 28 percent of the U.S. population.

  5. National Bladder Cancer Study - SEER Landmark Studies

    Science.gov (United States)

    SEER is an authoritative source of information on cancer incidence and survival in the United States. SEER currently collects and publishes cancer incidence and survival data from population-based cancer registries covering approximately 28 percent of the U.S. population.

  6. Agricultural Health Study - SEER Landmark Studies

    Science.gov (United States)

    SEER is an authoritative source of information on cancer incidence and survival in the United States. SEER currently collects and publishes cancer incidence and survival data from population-based cancer registries covering approximately 28 percent of the U.S. population.

  7. Gene for Melanoma - SEER Landmark Studies

    Science.gov (United States)

    SEER is an authoritative source of information on cancer incidence and survival in the United States. SEER currently collects and publishes cancer incidence and survival data from population-based cancer registries covering approximately 28 percent of the U.S. population.

  8. Genetic Susceptibility Sudies - SEER Landmark Studies

    Science.gov (United States)

    SEER is an authoritative source of information on cancer incidence and survival in the United States. SEER currently collects and publishes cancer incidence and survival data from population-based cancer registries covering approximately 28 percent of the U.S. population.

  9. Breast Cancer Surveillance Consortium - SEER Landmark Studies

    Science.gov (United States)

    SEER is an authoritative source of information on cancer incidence and survival in the United States. SEER currently collects and publishes cancer incidence and survival data from population-based cancer registries covering approximately 28 percent of the U.S. population.

  10. Registration now open for landmark CERN conference

    CERN Multimedia

    2003-01-01

    Journalist registration is now available for the Role of Science in the Information Society (RSIS) conference, to be held at CERN on 8-9 December....RSIS will explore future contributions of science to the information society based on past and present practice (1 page).

  11. Prostate Cancer Outcomes Study - SEER Landmark Studies

    Science.gov (United States)

    SEER is an authoritative source of information on cancer incidence and survival in the United States. SEER currently collects and publishes cancer incidence and survival data from population-based cancer registries covering approximately 28 percent of the U.S. population.

  12. Diet and Cancer - SEER Landmark Studies

    Science.gov (United States)

    SEER is an authoritative source of information on cancer incidence and survival in the United States. SEER currently collects and publishes cancer incidence and survival data from population-based cancer registries covering approximately 28 percent of the U.S. population.

  13. Endometrial Cancer and Estrogen - SEER Landmark Studies

    Science.gov (United States)

    SEER is an authoritative source of information on cancer incidence and survival in the United States. SEER currently collects and publishes cancer incidence and survival data from population-based cancer registries covering approximately 28 percent of the U.S. population.

  14. AIDS-Related Cancers - SEER Landmark Studies

    Science.gov (United States)

    SEER is an authoritative source of information on cancer incidence and survival in the United States. SEER currently collects and publishes cancer incidence and survival data from population-based cancer registries covering approximately 28 percent of the U.S. population.

  15. Physical Activity and Cancer - SEER Landmark Studies

    Science.gov (United States)

    SEER is an authoritative source of information on cancer incidence and survival in the United States. SEER currently collects and publishes cancer incidence and survival data from population-based cancer registries covering approximately 28 percent of the U.S. population.

  16. On-line SLAM using clustered landmarks with omnidirectional vision

    OpenAIRE

    Jun Okamoto Jr.; Vitor Campanholo Guizilini

    2010-01-01

    The problem of SLAM (simultaneous localization and mapping) is a fundamental problem in autonomous robotics. It arises when a robot must create a map of the regions it has navigated while localizing itself on it, using results from one step to increase precision in another by eliminating errors inherent to the sensors. One common solution consists of establishing landmarks in the environment which are used as reference points for absolute localization estimates and form a sparse map that is i...

  17. Visual landmarks facilitate rodent spatial navigation in virtual reality environments

    OpenAIRE

    Youngstrom, Isaac A.; Strowbridge, Ben W.

    2012-01-01

    Because many different sensory modalities contribute to spatial learning in rodents, it has been difficult to determine whether spatial navigation can be guided solely by visual cues. Rodents moving within physical environments with visual cues engage a variety of nonvisual sensory systems that cannot be easily inhibited without lesioning brain areas. Virtual reality offers a unique approach to ask whether visual landmark cues alone are sufficient to improve performance in a spatial task. We ...

  18. Hoffa's fat pad injuries and their relationship with anterior cruciate ligament tears: new observations based on MR imaging in patients and MR imaging and anatomic correlation in cadavers

    International Nuclear Information System (INIS)

    To determine the normal anatomic relationships of Hoffa's fat pad with the anterior cruciate ligament (ACL) and with the frequency of Hoffa's fat pad abnormalities in ACL-deficient knees. Retrospective clinical study on patients and observational anatomic study on cadavers. The study was approved by the Institutional Review Board. MR imaging studies of the knees of 100 patients (21-48 years old) with or without arthroscopically proven tears of the ACL, performed at a single institution, were reviewed by two readers for abnormalities of Hoffa's fat pad. Ten cadaveric knee specimens were studied with MR imaging and Faxitron radiographs, and by inspection of sections and histology. Alterations in Hoffa's fat pad on MR imaging were present in 64% (32/50) of patients with torn ACLs, and in 24% (12/50) of patients without a tear of the ACL (P < 0.05). Hoffa's fat pad inserted into the intercondylar notch in 50% (5/10) of cadaveric specimens, four in conjunction with the ligamentum mucosum and in one in an isolated fashion. Histological study demonstrated the composition of the ligamentum mucosum and Hoffa's fat pad and their course and insertion sites in the intercondylar notch. Abnormalities of Hoffa's fat pad, such as focal and diffuse edema, tears, scars and synovial proliferation, are more common in knees with torn ACLs than in knees with intact ACLs. (orig.)

  19. Dung beetles ignore landmarks for straight-line orientation.

    Science.gov (United States)

    Dacke, Marie; Byrne, Marcus; Smolka, Jochen; Warrant, Eric; Baird, Emily

    2013-01-01

    Upon locating a suitable dung pile, ball-rolling dung beetles shape a piece of dung into a ball and roll it away in a straight line. This guarantees that they will not return to the dung pile, where they risk having their ball stolen by other beetles. Dung beetles are known to use celestial compass cues such as the sun, the moon and the pattern of polarised light formed around these light sources to roll their balls of dung along straight paths. Here, we investigate whether terrestrial landmarks have any influence on straight-line orientation in dung beetles. We find that the removal or re-arrangement of landmarks has no effect on the beetle's orientation precision. Celestial compass cues dominate straight-line orientation in dung beetles so strongly that, under heavily overcast conditions or when prevented from seeing the sky, the beetles can no longer orient along straight paths. To our knowledge, this is the only animal with a visual compass system that ignores the extra orientation precision that landmarks can offer. PMID:23076443

  20. AUTOMATIC DETECTION AND CLASSIFICATION OF RETINAL VASCULAR LANDMARKS

    Directory of Open Access Journals (Sweden)

    Hadi Hamad

    2014-06-01

    Full Text Available The main contribution of this paper is introducing a method to distinguish between different landmarks of the retina: bifurcations and crossings. The methodology may help in differentiating between arteries and veins and is useful in identifying diseases and other special pathologies, too. The method does not need any special skills, thus it can be assimilated to an automatic way for pinpointing landmarks; moreover it gives good responses for very small vessels. A skeletonized representation, taken out from the segmented binary image (obtained through a preprocessing step, is used to identify pixels with three or more neighbors. Then, the junction points are classified into bifurcations or crossovers depending on their geometrical and topological properties such as width, direction and connectivity of the surrounding segments. The proposed approach is applied to the public-domain DRIVE and STARE datasets and compared with the state-of-the-art methods using proper validation parameters. The method was successful in identifying the majority of the landmarks; the average correctly identified bifurcations in both DRIVE and STARE datasets for the recall and precision values are: 95.4% and 87.1% respectively; also for the crossovers, the recall and precision values are: 87.6% and 90.5% respectively; thus outperforming other studies.

  1. Review of the Historical Evolution of Anatomical Terms

    Directory of Open Access Journals (Sweden)

    Algieri, Rubén D.

    2011-12-01

    Full Text Available Most of the medical terms of Greek origin are traditionally attributed to Hippocrates (460-370 BC. Claudius Galen of Pergamum (130-200 BC developed a classification of bones and joints and described different brain areas. His teachings have remained unchanged for over a thousand years. Andreas Vesalius of Brussels (1514-1564, through the systematic study of human body structure, changed many concepts. He published his work in his production "De humani corporis fabrica libri septem", where a special attention is evident to the discovery and description of new anatomical facts. From here there is a revolution in the morphological sciences, where the same anatomical structure passed to receive different names. In the nineteenth century, the different anatomists in the world decide to meet in order to unify criteria regarding the anatomical structures and determine a only one universal language in the anatomical sciences. In 1895, in Basel (Switzerland it’s approved a list of 5.573 terms, called Basle Nomina Anatomica (BNA and was written in Latin. Eponyms were deleted. In 1903, he founded the International Federation of Associations of anatomists (IFAA. In 1935, in Jena (Germany, approving the Jena Nomina Anatomica (JNA. In 1950, in Oxford, formed the Committee of the International Anatomical Nomenclature (IANC. In 1955, in Paris (France it is agreed to adopt a Latin nomenclature based on the BNA, the Paris Nomina Anatomica (PNA. In 1980, for the first time in Latin America, takes place on the 11th International Congress of Anatomists, Mexico. In 1989, the International Committee of Anatomical Nomenclature, published the sixth edition of the Nomina Anatomica, without review by the IFAA. The same year, the latter established a Federative International Committee of Anatomical Terminology (FICAT. In 1998, he published a new list FICAT: International Anatomical Terminology (TAI, with the structures named in Latin language and their equivalence in English, listing which updates and supersedes all previous nomenclatures. In September 2001, the Spanish Anatomical Society translated this International Anatomical Terminology into Spanish language.The study of the historical backgrounds in the worldwide development of Anatomical Terms, give us valuable data about the origin and foundation of the names. It is necessary to raise awareness about the implementation of a unified, updated and uniform anatomical terminology, when conducting scientific communications and publications. As specialists in this discipline, we must study and know the existence of the official list of anatomical terms of use worldwide (International Anatomical Terminology, its equivalence with previous classifications, keeping us updated about its changes to teach it to new generations of health professionals.

  2. Delineating anatomical boundaries using the boundary fragment model.

    OpenAIRE

    Stebbing, RV; Noble, JA

    2013-01-01

    In this paper we present a method to automatically isolate relevant anatomical boundary positions in an image using only the structure of edges. The purpose of this method is to facilitate model-based segmentation algorithms which rely on accurate initialisation and assume that the correct anatomical boundary positions are close to the current model surface. The method is built around a weak parts-based shape model - the Boundary Fragment Model (BFM) - which represents an object by sections o...

  3. Fusion of WiFi, Smartphone Sensors and Landmarks Using the Kalman Filter for Indoor Localization

    Directory of Open Access Journals (Sweden)

    Zhenghua Chen

    2015-01-01

    Full Text Available Location-based services (LBS have attracted a great deal of attention recently. Outdoor localization can be solved by the GPS technique, but how to accurately and efficiently localize pedestrians in indoor environments is still a challenging problem. Recent techniques based on WiFi or pedestrian dead reckoning (PDR have several limiting problems, such as the variation of WiFi signals and the drift of PDR. An auxiliary tool for indoor localization is landmarks, which can be easily identified based on specific sensor patterns in the environment, and this will be exploited in our proposed approach. In this work, we propose a sensor fusion framework for combining WiFi, PDR and landmarks. Since the whole system is running on a smartphone, which is resource limited, we formulate the sensor fusion problem in a linear perspective, then a Kalman filter is applied instead of a particle filter, which is widely used in the literature. Furthermore, novel techniques to enhance the accuracy of individual approaches are adopted. In the experiments, an Android app is developed for real-time indoor localization and navigation. A comparison has been made between our proposed approach and individual approaches. The results show significant improvement using our proposed framework. Our proposed system can provide an average localization accuracy of 1 m.

  4. Fusion of WiFi, smartphone sensors and landmarks using the Kalman filter for indoor localization.

    Science.gov (United States)

    Chen, Zhenghua; Zou, Han; Jiang, Hao; Zhu, Qingchang; Soh, Yeng Chai; Xie, Lihua

    2015-01-01

    Location-based services (LBS) have attracted a great deal of attention recently. Outdoor localization can be solved by the GPS technique, but how to accurately and efficiently localize pedestrians in indoor environments is still a challenging problem. Recent techniques based on WiFi or pedestrian dead reckoning (PDR) have several limiting problems, such as the variation of WiFi signals and the drift of PDR. An auxiliary tool for indoor localization is landmarks, which can be easily identified based on specific sensor patterns in the environment, and this will be exploited in our proposed approach. In this work, we propose a sensor fusion framework for combining WiFi, PDR and landmarks. Since the whole system is running on a smartphone, which is resource limited, we formulate the sensor fusion problem in a linear perspective, then a Kalman filter is applied instead of a particle filter, which is widely used in the literature. Furthermore, novel techniques to enhance the accuracy of individual approaches are adopted. In the experiments, an Android app is developed for real-time indoor localization and navigation. A comparison has been made between our proposed approach and individual approaches. The results show significant improvement using our proposed framework. Our proposed system can provide an average localization accuracy of 1 m. PMID:25569750

  5. A comparative study of anatomic structures on the panoramic radiograph and some extraoral radiographs

    International Nuclear Information System (INIS)

    The author has studied each landmark for successful interpretation in the radiograph of the head that have the complex anatomic structures, using panoramic radiograph, postero-anterior cephalometric radiograph, lateral cephalometric radiograph, Waters' radiograph of the skull. The anatomic structures of the human dry skull attached by radiopaque materials were taken radiographs and analysed comparatively. The results were as follows: 1. The overall anatomic structures of the mandible showed sharp images in the panoramic radiograph than other radiographs with relatively less distortion, superimposition, blurring of the image. 2. The anatomic structures were situated on sagittal plane of the skull showed blurred images in panoramic radiograph than other radiographs. 3. The anatomic structures which were situated on the basal portion of the skull showed blurred and secondary images in the panoramic radiograph than other radiographs. 4. In the panoramic radiograph, the lower 3rd portion of the orbit appeared to be superimposed with the superior portion of the maxillary sinus and the medial and lateral surface of the nasal cavity showed extensively superimposition of the orbit and the maxillary sinus, which images showed blurring. 5. The inferior surface and posterior surface of maxillary sinus showed to be good image in the panoramic radiograph than other radiographs. 6. In the panoramic radiograph, line of maxillary bone between lateral pterygoid plate, line of maxillary bone between zygomatic bone showed distinct image with another structures.

  6. Slice-based supine to standing postured deformation for chinese anatomical models and the dosimetric results by wide band frequency electromagnetic field exposure: Morphing

    International Nuclear Information System (INIS)

    Digital human models are frequently obtained from supine-postured medical images or cadaver slices, but many applications require standing models. This paper presents the work of reconstructing standing Chinese adult anatomical models from supine postured slices. Apart from the previous studies, the deformation works on 2-D segmented slices. The surface profile of the standing posture is adjusted by population measurement data. A non-uniform texture amplification approach is applied on the 2-D slices to recover the skin contour and to redistribute the internal tissues. Internal organ shift due to postures is taken into account. The feet are modified by matrix rotation. Then, the supine and standing models are utilised for the evaluation of electromagnetic field exposure over wide band frequency and different incident directions. . (authors)

  7. Probabilistic anatomical labeling of brain structures using statistical probabilistic anatomical maps

    International Nuclear Information System (INIS)

    The use of statistical parametric mapping (SPM) program has increased for the analysis of brain PET and SPECT images. Montreal neurological institute (MNI) coordinate is used in SPM program as a standard anatomical framework. While the most researchers look up Talairach atlas to report the localization of the activations detected in SPM program, there is significant disparity between MNI templates and Talairach atlas. That disparity between Talairach and MNI coordinates makes the interpretation of SPM result time consuming, subjective and inaccurate. The purpose of this study was to develop a program to provide objective anatomical information of each x-y-z position in ICBM coordinate. Program was designed to provide the anatomical information for the given x-y-z position in MNI coordinate based on the statistical probabilistic anatomical map (SPAM) images of ICBM. When x-y-z position was given to the program, names of the anatomical structures with non-zero probability and the probabilities that the given position belongs to the structures were tabulated. The program was coded using IDL and JAVA language for the easy transplantation to any operating system or platform. Utility of this program was shown by comparing the results of this program to those of SPM program. Preliminary validation study was performed by applying this program to the analysis of PET brain activation study of human memory in which the anatomical information on the activated areas are previously known. Real time retrieval of probabilistic information with 1 mm spatial resolution was archived using the programs. Validation study showed the relevance of this program: probability that the activated area for memory belonged to hippocampal formation was more than 80%. These programs will be useful for the result interpretation of the image analysis performed on MNI coordinate, as done in SPM program

  8. Applying the functional abnormality ontology pattern to anatomical functions

    Directory of Open Access Journals (Sweden)

    Hoehndorf Robert

    2010-03-01

    Full Text Available Abstract Background Several biomedical ontologies cover the domain of biological functions, including molecular and cellular functions. However, there is currently no publicly available ontology of anatomical functions. Consequently, no explicit relation between anatomical structures and their functions is expressed in the anatomy ontologies that are available for various species. Such an explicit relation between anatomical structures and their functions would be useful both for defining the classes of the anatomy and the phenotype ontologies accurately. Results We provide an ontological analysis of functions and functional abnormalities. From this analysis, we derive an approach to the automatic extraction of anatomical functions from existing ontologies which uses a combination of natural language processing, graph-based analysis of the ontologies and formal inferences. Additionally, we introduce a new relation to link material objects to processes that realize the function of these objects. This relation is introduced to avoid a needless duplication of processes already covered by the Gene Ontology in a new ontology of anatomical functions. Conclusions Ontological considerations on the nature of functional abnormalities and their representation in current phenotype ontologies show that we can extract a skeleton for an ontology of anatomical functions by using a combination of process, phenotype and anatomy ontologies automatically. We identify several limitations of the current ontologies that still need to be addressed to ensure a consistent and complete representation of anatomical functions and their abnormalities. Availability The source code and results of our analysis are available at http://bioonto.de.

  9. Study on the Construction of a High-definition Whole-body Voxel Model based on Cadaver's Color Photographic Anatomical Slice Images and Monte Carlo Dose Calculations

    International Nuclear Information System (INIS)

    Ajou University School of Medicine made the serially sectioned anatomical images from the Visible Korean Human (VKH) Project in Korea. The VKH images, which are the high-resolution color photographic images, show the organs and tissues in the human body very clearly at 0.2 mm intervals. In this study, we constructed a high-quality voxel model (VKH-Man) with a total of 30 organs and tissues by manual and automatic segmentation method using the serially sectioned anatomical image data from the Visible Korean Human (VKH) project in Korea. The height and weight of VKH-Man voxel model is 164 cm and 57.6 kg, respectively, and the voxel resolution is 1.875 x 1.875 x 2 mm3. However, this voxel phantom can be used to calculate the organ and tissue doses of only one person. Therefore, in this study, we adjusted the voxel phantom to the 'Reference Korean' data to construct the voxel phantom that represents the radiation workers in Korea. The height and weight of the voxel model (HDRK-Man) that is finally developed are 171 cm and 68 kg, respectively, and the voxel resolution is 1.981 x 1.981 x 2.0854 mm3. VKH-Man and HDRK-Man voxel model were implemented in a Monte Carlo particle transport simulation code for calculation of the organ and tissue doses in various irradiation geometries. The calculated values were compared with each other to see the effect of the adjustment and also compared with other computational models (KTMAN-2, ICRP-74 and VIP-Man). According to the results, the adjustment of the voxel model was found hardly affect the dose calculations and most of the organ and tissue equivalent doses showed some differences among the models. These results shows that the difference in figure, and organ topology affects the organ doses more than the organ size. The calculated values of the effective dose from VKH-Man and HDRK-Man according to the ICRP-60 and upcoming ICRP recommendation were compared. For the other radiation geometries (AP, LLAT, RLAT) except for PA radiation geometry, the effective dose according to the upcoming ICRP recommendation was somewhat larger than that according to the ICRP-60. This seems due to change of the tissue weighting factor in the upcoming ICRP recommendation. The developed phantoms (VKH-Man and HDRK-Man) are expected to be used to estimate the radiation risk of only Korean in external and internal dosimetry. Dose conversion coefficients calculated in this study are also expected to be used in radiation protection assessment of Korean since those were distinguished from those of the western

  10. Defining esophageal landmarks, gastroesophageal reflux disease, and Barrett's esophagus.

    Science.gov (United States)

    DeVault, Kenneth; McMahon, Barry P; Celebi, Altay; Costamagna, Guido; Marchese, Michele; Clarke, John O; Hejazi, Reza A; McCallum, Richard W; Savarino, Vincenzo; Zentilin, Patrizia; Savarino, Edoardo; Thomson, Mike; Souza, Rhonda F; Donohoe, Claire L; O'Farrell, Naoimh J; Reynolds, John V

    2013-10-01

    The following paper on gastroesophageal reflux disease (GERD) and Barrett's esophagus (BE) includes commentaries on defining esophageal landmarks; new techniques for evaluating upper esophageal sphincter (UES) tone; differential diagnosis of GERD, BE, and hiatal hernia (HH); the use of high-resolution manometry for evaluation of reflux; the role of fundic relaxation in reflux; the use of 24-h esophageal pH-impedance testing in differentiating acid from nonacid reflux and its potential inclusion in future Rome criteria; classification of endoscopic findings in GERD; the search for the cell origin that generates BE; and the relationship between BE, Barrett's carcinoma, and obesity. PMID:24117649

  11. Exploring brain function from anatomical connectivity

    Directory of Open Access Journals (Sweden)

    Gorka Zamora-López

    2011-06-01

    Full Text Available The intrinsic relationship between the architecture of the brain and the range of sensory and behavioral phenomena it produces is a relevant question in neuroscience. Here, we review recent knowledge gained on the architecture of the anatomical connectivity by means of complex network analysis. It has been found that corticocortical networks display a few prominent characteristics: (i modular organization, (ii abundant alternative processing paths and (iii the presence of highly connected hubs. Additionally, we present a novel classification of cortical areas of the cat according to the role they play in multisensory connectivity. All these properties represent an ideal anatomical substrate supporting rich dynamical behaviors, as-well-as facilitating the capacity of the brain to process sensory information of different modalities segregated and to integrate them towards a comprehensive perception of the real world. The result here exposed are mainly based in anatomical data of cats’ brain, but we show how further observations suggest that, from worms to humans, the nervous system of all animals might share fundamental principles of organization.

  12. Quantifying anatomical shape variations in neurological disorders.

    Science.gov (United States)

    Singh, Nikhil; Fletcher, P Thomas; Preston, J Samuel; King, Richard D; Marron, J S; Weiner, Michael W; Joshi, Sarang

    2014-04-01

    We develop a multivariate analysis of brain anatomy to identify the relevant shape deformation patterns and quantify the shape changes that explain corresponding variations in clinical neuropsychological measures. We use kernel Partial Least Squares (PLS) and formulate a regression model in the tangent space of the manifold of diffeomorphisms characterized by deformation momenta. The scalar deformation momenta completely encode the diffeomorphic changes in anatomical shape. In this model, the clinical measures are the response variables, while the anatomical variability is treated as the independent variable. To better understand the "shape-clinical response" relationship, we also control for demographic confounders, such as age, gender, and years of education in our regression model. We evaluate the proposed methodology on the Alzheimer's Disease Neuroimaging Initiative (ADNI) database using baseline structural MR imaging data and neuropsychological evaluation test scores. We demonstrate the ability of our model to quantify the anatomical deformations in units of clinical response. Our results also demonstrate that the proposed method is generic and generates reliable shape deformations both in terms of the extracted patterns and the amount of shape changes. We found that while the hippocampus and amygdala emerge as mainly responsible for changes in test scores for global measures of dementia and memory function, they are not a determinant factor for executive function. Another critical finding was the appearance of thalamus and putamen as most important regions that relate to executive function. These resulting anatomical regions were consistent with very high confidence irrespective of the size of the population used in the study. This data-driven global analysis of brain anatomy was able to reach similar conclusions as other studies in Alzheimer's disease based on predefined ROIs, together with the identification of other new patterns of deformation. The proposed methodology thus holds promise for discovering new patterns of shape changes in the human brain that could add to our understanding of disease progression in neurological disorders. PMID:24667299

  13. Statistical analysis of shape through triangulation of landmarks: A study of sexual dimorphism in hominids

    OpenAIRE

    Rao, Calyampudi R.; Suryawanshi, Shailaja

    1998-01-01

    Two objects with homologous landmarks are said to be of the same shape if the configuration of landmarks of one object can be exactly matched with that of the other by translation, rotation/reflection, and scaling. In an earlier paper, the authors proposed statistical analysis of shape by considering logarithmic differences of all possible Euclidean distances between landmarks. Tests of significance for differences in the shape of objects and methods of discrimination between populations were...

  14. From Objects to Landmarks: The Function of Visual Location Information in Spatial Navigation

    OpenAIRE

    OliverBaumann; MarkA.Bellgrove

    2012-01-01

    Landmarks play an important role in guiding navigational behavior. A host of studies in the last 15?years has demonstrated that environmental objects can act as landmarks for navigation in different ways. In this review, we propose a parsimonious four-part taxonomy for conceptualizing object location information during navigation. We begin by outlining object properties that appear to be important for a landmark to attain salience. We then systematically examine the different functions of obj...

  15. APFiLoc: An Infrastructure-Free Indoor Localization Method Fusing Smartphone Inertial Sensors, Landmarks and Map Information

    Directory of Open Access Journals (Sweden)

    Jianga Shang

    2015-10-01

    Full Text Available The utility and adoption of indoor localization applications have been limited due to the complex nature of the physical environment combined with an increasing requirement for more robust localization performance. Existing solutions to this problem are either too expensive or too dependent on infrastructure such as Wi-Fi access points. To address this problem, we propose APFiLoc—a low cost, smartphone-based framework for indoor localization. The key idea behind this framework is to obtain landmarks within the environment and to use the augmented particle filter to fuse them with measurements from smartphone sensors and map information. A clustering method based on distance constraints is developed to detect organic landmarks in an unsupervised way, and the least square support vector machine is used to classify seed landmarks. A series of real-world experiments were conducted in complex environments including multiple floors and the results show APFiLoc can achieve 80% accuracy (phone in the hand and around 70% accuracy (phone in the pocket of the error less than 2 m error without the assistance of infrastructure like Wi-Fi access points.

  16. APFiLoc: An Infrastructure-Free Indoor Localization Method Fusing Smartphone Inertial Sensors, Landmarks and Map Information.

    Science.gov (United States)

    Shang, Jianga; Gu, Fuqiang; Hu, Xuke; Kealy, Allison

    2015-01-01

    The utility and adoption of indoor localization applications have been limited due to the complex nature of the physical environment combined with an increasing requirement for more robust localization performance. Existing solutions to this problem are either too expensive or too dependent on infrastructure such as Wi-Fi access points. To address this problem, we propose APFiLoc-a low cost, smartphone-based framework for indoor localization. The key idea behind this framework is to obtain landmarks within the environment and to use the augmented particle filter to fuse them with measurements from smartphone sensors and map information. A clustering method based on distance constraints is developed to detect organic landmarks in an unsupervised way, and the least square support vector machine is used to classify seed landmarks. A series of real-world experiments were conducted in complex environments including multiple floors and the results show APFiLoc can achieve 80% accuracy (phone in the hand) and around 70% accuracy (phone in the pocket) of the error less than 2 m error without the assistance of infrastructure like Wi-Fi access points. PMID:26516858

  17. On the new anatomical nomenclature.

    Science.gov (United States)

    Marecková, E; Simon, F; Cervený, L

    2001-05-01

    The present paper is concerned with the linguistic aspect of the new anatomical nomenclature (Terminologia Anatomica 1998). Orthographic, morphological, syntactic, lexical, and terminological comments are presented. In the authors' opinion, shortcomings might have been effectively avoided by cooperation with linguists. PMID:11396787

  18. Anatomical terminology and nomenclature: past, present and highlights.

    Science.gov (United States)

    Kachlik, David; Baca, Vaclav; Bozdechova, Ivana; Cech, Pavel; Musil, Vladimir

    2008-08-01

    The anatomical terminology is a base for medical communication. It is elaborated into a nomenclature in Latin. Its history goes back to 1895, when the first Latin anatomical nomenclature was published as Basiliensia Nomina Anatomica. It was followed by seven revisions (Jenaiensia Nomina Anatomica 1935, Parisiensia Nomina Anatomica 1955, Nomina Anatomica 2nd to 6th edition 1960-1989). The last revision, Terminologia Anatomica, (TA) created by the Federative Committee on Anatomical Terminology and approved by the International Federation of Associations of Anatomists, was published in 1998. Apart from the official Latin anatomical terminology, it includes a list of recommended English equivalents. In this article, major changes and pitfalls of the nomenclature are discussed, as well as the clinical anatomy terms. The last revision (TA) is highly recommended to the attention of not only teachers, students and researchers, but also to clinicians, doctors, translators, editors and publishers to be followed in their activities. PMID:18488135

  19. 3D CT-based cephalometric analysis: 3D cephalometric theoretical concept and software

    International Nuclear Information System (INIS)

    We present an original three-dimensional cephalometric analysis based on a transformation of a classical two dimensional topological cephalometry. To validate the three-dimensional cephalometric CT based concept we systematically compared the alignments of anatomic structures. We used digital lateral radiography to perform the classical two-dimensional cephalometry, and a three-dimensional CT surface model for the three-dimensional cephalometry. Diagnoses based on both two-dimensional and three-dimensional analyses were adequate, but the three-dimensional analysis gave more information such as the possibility of comparing the right and left side of the skull. Also the anatomic structures were not superimposed which improved the visibility of the reference landmarks. We demonstrated that three-dimensional analysis gives the same results as two-dimensional analysis using the same skull. We also present possible applications of the method. (orig.)

  20. Anatomical or mirror mode imitation? A behavioral approach.

    Science.gov (United States)

    Pierpaoli, C; Ferrante, L; Manzoni, T; Fabri, M

    2014-03-01

    Imitation can occur in at least two forms: one, which can be defined as anatomical, is based primarily on the mental construct of the body schema and allows recognition of correspondences between own body anatomy and that of other individuals. The other form, defined as specular or mirror mode, is most probably based on the allocation of some form of attention to the same region of the environmental space both by model and imitator, and to the objects it contains. This study investigated the behavioral strategy of imitation in normal subjects, to assess whether they carried out task instructions using an anatomical or a mirror perspective. Twenty seven adults were asked to imitate intransitive meaningful and meaningless gestures shown by a model in video clips. Instructions about how to perform them were provided before each trial. Trials were free (intended to produce spontaneous imitation) or driven (intended to produce anatomical imitation); further driven trials were administered to verify participants' knowledge of bodily laterality and were used as control. Performances were interpreted as anatomical or mirror imitation, according to the observation of anatomical or spatial reference frames between stimulus and imitator. The results revealed that in spontaneous imitation the mirror mode was more frequent (61% of responses), in line with previous studies. The novel finding was the prevalence (93% of responses) of anatomical imitation in tasks involving detailed driven instructions. PMID:25181594

  1. Application of the Restriction Landmark Genome Scanning (RLGS Method for Analysis of Genetic Diversity between Asian and African Sorghum

    Directory of Open Access Journals (Sweden)

    Hisato Okuizumi*, Tomotsugu Noguchi, Tatsuya Saguchi,Takuma Fujita, Eri Nonaka, Shinsuke Yamanaka, Koffi Kombate, Subbarayan Sivakumar , Kulandaivelu Ganesamurthy, Yasufumi Murakami

    2010-07-01

    Full Text Available Restriction Landmark Genome Scanning (RLGS used to detect large numbers of restriction landmarks in a single experiment andapplied to analyze the genetic diversity of Asian and African sorghum accessions. This method is one of the genome analysistools based on the concept that restriction enzyme sites can serve as landmarks throughout a genome. RLGS uses direct endlabelingof the genomic DNA digested with a rare-cutting restriction enzyme and high-resolution two-dimensionalelectrophoresis. It has an advantage of providing precise information on a spot intensity that reflects the copy number ofrestriction landmarks and to visualize differences in methylation levels across the genome. RLGS becomes very useful for doingwhole genome scans that equals the work of thousands of polymerase chain reactions. A study was carried out using Sorghumaccessions collected from countries viz., Morocco, Nigeria, Sudan, South Africa, Japan, South Korea, and China. Onerepresentative sample was chosen from a country for analysis carried out at National Institute of Agrobiological Sciences(NIAS. Two dimensional spot images for seven accessions obtained and spot intensities were scanned. Totally, 119 spots weredetected of which 95 spots observed as polymorphic and 24 as non polymorphic. Unique presence and null spots werespecifically detected in all accessions taken for study. A total of 37 unique spots and 12 null spots, detected in this experiment.Principal Coordinate Analysis indicated, four African accessions scattered in the diagram were diverse and three Asianaccessions closely distributed with narrow diversity. The phylogenetic tree showed that Sudan and Nigerian accessions weredistant while Chinna, Japan and Korea accessions had close proximity

  2. Maximized Posteriori Attributes Selection from Facial Salient Landmarks for Face Recognition

    CERN Document Server

    Gupta, Phalguni; Sing, Jamuna Kanta; Tistarelli, Massimo

    2010-01-01

    This paper presents a robust and dynamic face recognition technique based on the extraction and matching of devised probabilistic graphs drawn on SIFT features related to independent face areas. The face matching strategy is based on matching individual salient facial graph characterized by SIFT features as connected to facial landmarks such as the eyes and the mouth. In order to reduce the face matching errors, the Dempster-Shafer decision theory is applied to fuse the individual matching scores obtained from each pair of salient facial features. The proposed algorithm is evaluated with the ORL and the IITK face databases. The experimental results demonstrate the effectiveness and potential of the proposed face recognition technique also in case of partially occluded faces.

  3. Proposal of anatomical terminology to call the arteries of the base of the encephalon in the monkey (Cebus paella L., 1766 Nomenclatura proposta para denominar as artérias da base do encéfalo do macaco-prego (Cebus apella L., 1766

    Directory of Open Access Journals (Sweden)

    Jussara Rocha Ferreira

    2001-05-01

    Full Text Available Arteries of the encephalon basis of 30 monkeys (Cebus paella were studied. Arteries were injected with colored latex, fixed in formaldehyde solution at 10% and dissected under magnifying lenses. Since the animals died from natural causes they had been previously used in other experiments. Human and veterinary anatomical terminology and literature were used as a reference for the determination of vessels studied in the primates. Arteries of the encephalon base represent division branches of three vascular pedicules: the right and left internal carotid arteries and the basilar system. Vessels in the basilar system of the animal were called vertebral arteries; anterior spinal artery; anterior and posterior cerebelar arteries; pontine arteries; satellite cerebelar arteries; caudal and cranial cerebelar arteries. The basilar artery bifurcates into two posterior cerebral arteries (100%. The caudal area of the encephalon’s arterial circuit is thus constituted. Linking between the vertebro-basilar and the carotid segments is done by the posterior communicating artery, that caudally anastomizes (100% with the posterior cerebral artery. The internal carotid artery gives origin to the posterior communicating artery. The right and left internal carotid artery (intracranial portion compounds the carotid system. The following vessels were identified: middle cerebral artery; anterior cerebral artery; interhemispheric artery; olfactory arteries. Results report that Cebus paella presents an arterial pattern of relative morphological stabilityEstudaram-se as artérias da base do encéfalo do Cebus apella em 30 animais, vindos a óbito por morte natural no Zoológico de São Paulo e coletados durante 10 anos. O material recebeu injeção de látex corado, fixado em formol a 10%, e foi dissecado sob lupa. Encontramos dificuldade e denominar estes vasos. As terminologias anatômicas humana e veterinária e a recuperação da literatura nos serviram de base para sugerirmos uma denominação que se adequasse ao modelo arterial desse primata. Os resultados nos permitiram verificar, no circuito arterial da base do encéfalo, segmento caudal ou vértebro-basilar as artérias (a: a. vertebral, suas partes (pé-vertebral, cervical, atlântica e intracraniana com ramos meníngeos e seus ramos (a. espinhal anterior, a. cerebelar inferior caudal, ramos para a medula oblonga; a. basilar e seus ramos (a. cerebelar inferior rostral, a. pontinas, a. cerebelar superior satélite, ilhas artérias, a. cerebelar anterior, a. cerebelar posterior; e no segmento rostral ou carótico os vasos: a. carótida interna (parte cerebral; a. comunicante posterior; a. coróidea; a. cerebral média; a. cerebral anterior; a. olfatória; a. inter-hemisférica. A análise dos resultados nos permitiu considerar que o Cebus apella apresentou um padrão arterial de relativa estabilidade morfológica em função das poucas variações encontradas nos vasos formadores dos circuitos arteriais considerados

  4. Quantification of organ motion based on an adaptive image-based scale invariant feature method

    Energy Technology Data Exchange (ETDEWEB)

    Paganelli, Chiara [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, piazza L. Da Vinci 32, Milano 20133 (Italy); Peroni, Marta [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, piazza L. Da Vinci 32, Milano 20133, Italy and Paul Scherrer Institut, Zentrum für Protonentherapie, WMSA/C15, CH-5232 Villigen PSI (Italy); Baroni, Guido; Riboldi, Marco [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, piazza L. Da Vinci 32, Milano 20133, Italy and Bioengineering Unit, Centro Nazionale di Adroterapia Oncologica, strada Campeggi 53, Pavia 27100 (Italy)

    2013-11-15

    Purpose: The availability of corresponding landmarks in IGRT image series allows quantifying the inter and intrafractional motion of internal organs. In this study, an approach for the automatic localization of anatomical landmarks is presented, with the aim of describing the nonrigid motion of anatomo-pathological structures in radiotherapy treatments according to local image contrast.Methods: An adaptive scale invariant feature transform (SIFT) was developed from the integration of a standard 3D SIFT approach with a local image-based contrast definition. The robustness and invariance of the proposed method to shape-preserving and deformable transforms were analyzed in a CT phantom study. The application of contrast transforms to the phantom images was also tested, in order to verify the variation of the local adaptive measure in relation to the modification of image contrast. The method was also applied to a lung 4D CT dataset, relying on manual feature identification by an expert user as ground truth. The 3D residual distance between matches obtained in adaptive-SIFT was then computed to verify the internal motion quantification with respect to the expert user. Extracted corresponding features in the lungs were used as regularization landmarks in a multistage deformable image registration (DIR) mapping the inhale vs exhale phase. The residual distances between the warped manual landmarks and their reference position in the inhale phase were evaluated, in order to provide a quantitative indication of the registration performed with the three different point sets.Results: The phantom study confirmed the method invariance and robustness properties to shape-preserving and deformable transforms, showing residual matching errors below the voxel dimension. The adapted SIFT algorithm on the 4D CT dataset provided automated and accurate motion detection of peak to peak breathing motion. The proposed method resulted in reduced residual errors with respect to standard SIFT, providing a motion description comparable to expert manual identification, as confirmed by DIR.Conclusions: The application of the method to a 4D lung CT patient dataset demonstrated adaptive-SIFT potential as an automatic tool to detect landmarks for DIR regularization and internal motion quantification. Future works should include the optimization of the computational cost and the application of the method to other anatomical sites and image modalities.

  5. Quantification of organ motion based on an adaptive image-based scale invariant feature method

    International Nuclear Information System (INIS)

    Purpose: The availability of corresponding landmarks in IGRT image series allows quantifying the inter and intrafractional motion of internal organs. In this study, an approach for the automatic localization of anatomical landmarks is presented, with the aim of describing the nonrigid motion of anatomo-pathological structures in radiotherapy treatments according to local image contrast.Methods: An adaptive scale invariant feature transform (SIFT) was developed from the integration of a standard 3D SIFT approach with a local image-based contrast definition. The robustness and invariance of the proposed method to shape-preserving and deformable transforms were analyzed in a CT phantom study. The application of contrast transforms to the phantom images was also tested, in order to verify the variation of the local adaptive measure in relation to the modification of image contrast. The method was also applied to a lung 4D CT dataset, relying on manual feature identification by an expert user as ground truth. The 3D residual distance between matches obtained in adaptive-SIFT was then computed to verify the internal motion quantification with respect to the expert user. Extracted corresponding features in the lungs were used as regularization landmarks in a multistage deformable image registration (DIR) mapping the inhale vs exhale phase. The residual distances between the warped manual landmarks and their reference position in the inhale phase were evaluated, in order to provide a quantitative indication of the registration performed with the three different point sets.Results: The phantom study confirmed the method invariance and robustness properties to shape-preserving and deformable transforms, showing residual matching errors below the voxel dimension. The adapted SIFT algorithm on the 4D CT dataset provided automated and accurate motion detection of peak to peak breathing motion. The proposed method resulted in reduced residual errors with respect to standard SIFT, providing a motion description comparable to expert manual identification, as confirmed by DIR.Conclusions: The application of the method to a 4D lung CT patient dataset demonstrated adaptive-SIFT potential as an automatic tool to detect landmarks for DIR regularization and internal motion quantification. Future works should include the optimization of the computational cost and the application of the method to other anatomical sites and image modalities

  6. Anatomical structure of Polystichum Roth ferns rachises

    Directory of Open Access Journals (Sweden)

    Oksana V. Tyshchenko

    2012-03-01

    Full Text Available The morpho-anatomical characteristics of rachis cross sections of five Polystichum species is presented. The main and auxiliary anatomical features which help to distinguish investigated species are revealed.

  7. Parametric Anatomical Modeling: a method for modeling the anatomical layout of neurons and their projections

    OpenAIRE

    Martin Pyka; Sebastian Klatt

    2014-01-01

    Computational models of neural networks can be based on a variety of different parameters. These parameters include, for example, the 3d shape of neuron layers, the neurons' spatial projection patterns, spiking dynamics and neurotransmitter systems. While many well-developed approaches are available to model, for example, the spiking dynamics, there is a lack of approaches for modeling the anatomical layout of neurons and their projections. We present a new method, called Parametric Anatomica...

  8. Clinical study of quantitative analysis of the anatomical structure after canalicular laceration

    Directory of Open Access Journals (Sweden)

    Min Wei

    2013-06-01

    Full Text Available AIM: To quantitatively analyse the anatomical structure after canalicular laceration, to provide a basis for finding nasal ends of the canalicular and to evaluate the feasibility of taking the lacrimal caruncle as anatomic landmarks for finding the nasal ends of the inferior canalicular. METHODS: In this prospective case-control study, 100 cases(72 males and 28 femalesof traumatic inferior canalicular laceration were chosen. They were completely random divided into the experimental group(n=50, finding the nasal ends of the inferior canalicular by applying the method of lacrimal caruncle anatomic landmarks; the control group(n=50, finding the nasal ends of the inferior canalicular by applying the direct vision method. The distance of the lacrimal punctum and the temporal side of the stump, the vertical distance and quadrant between nasal ends of the canalicular and lacrimal caruncle were measured. The success rate of the two groups to find the nasa lends of the canalicular were recorded. The data were compared using ?2 test. RESULTS: The nasal ends of the inferior canalicular in the semi-quadrant of the lacrimal caruncle was 94%. The canalicular nasal ends from the lacrimal caruncle of the vertical distance was 2.34±0.68 mm,in which lacrimal punctums pitch temporal side of the stump7mm was 3.05±0.97mm. The success rate of surgery looking the inferior lacrimal duct nasal stump: experimental group: 49/50(98%, control group: 40/50(80%, the difference was statistically significant(PCONCLUSION: Nasal ends of the inferior canalicular locates below the parallel lines of the lacrimal caruncle. The canalicular nasal ends locates in the deep side of the lacrimal caruncle within 2-3mm. The lacrimal punctum and the length of the temporal side can be used to clear the radius around the lacrimal caruncle. The success rate of finding the nasal ends of the experimental group is faster than the control group. The lacrimal caruncle as anatomic landmarks to find the nasal ends of the inferior canalicular is feasible, especially for patients whose inferior canalicular bitamporal side of the stump from inferior lacrimal punctum was 4-7mm.

  9. The Development of Landmark and Beacon Use in Young Children: Evidence from a Touchscreen Search Task

    Science.gov (United States)

    Sutton, Jennifer E.

    2006-01-01

    Children ages 2, 3 and 4 years participated in a novel hide-and-seek search task presented on a touchscreen monitor. On beacon trials, the target hiding place could be located using a beacon cue, but on landmark trials, searching required the use of a nearby landmark cue. In Experiment 1, 2-year-olds performed less accurately than older children…

  10. Looking beyond the Boundaries: Time to Put Landmarks Back on the Cognitive Map?

    Science.gov (United States)

    Lew, Adina R.

    2011-01-01

    Since the proposal of Tolman (1948) that mammals form maplike representations of familiar environments, cognitive map theory has been at the core of debates on the fundamental mechanisms of animal learning and memory. Traditional formulations of cognitive map theory emphasize relations between landmarks and between landmarks and goal locations as…

  11. 36 CFR 13.1904 - Kennecott Mines National Historic Landmark (KNHL).

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Kennecott Mines National Historic Landmark (KNHL). 13.1904 Section 13.1904 Parks, Forests, and Public Property NATIONAL PARK SERVICE... National Park and Preserve § 13.1904 Kennecott Mines National Historic Landmark (KNHL). A map showing...

  12. 36 CFR 65.9 - Withdrawal of National Historic Landmark designation.

    Science.gov (United States)

    2010-07-01

    ... National Register criteria for evalution in 36 CFR 60.4, except if the property is redesignated on... Historic Landmark designation. 65.9 Section 65.9 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL HISTORIC LANDMARKS PROGRAM § 65.9 Withdrawal of National...

  13. 75 FR 16837 - Public Review of Draft United States Thoroughfare, Landmark, and Postal Address Data Standard

    Science.gov (United States)

    2010-04-02

    ... Address Data Standard AGENCY: Department of the Interior, U.S. Geological Survey. ACTION: Notice; request for comments on draft United States Thoroughfare, Landmark, and Postal Address Data Standard through... the draft United States Thoroughfare, Landmark, and Postal Address Data Standard. The United...

  14. An Evaluation of Cellular Neural Networks for the Automatic Identification of Cephalometric Landmarks on Digital Images

    Directory of Open Access Journals (Sweden)

    Rosalia Leonardi

    2009-01-01

    Full Text Available Several efforts have been made to completely automate cephalometric analysis by automatic landmark search. However, accuracy obtained was worse than manual identification in every study. The analogue-to-digital conversion of X-ray has been claimed to be the main problem. Therefore the aim of this investigation was to evaluate the accuracy of the Cellular Neural Networks approach for automatic location of cephalometric landmarks on softcopy of direct digital cephalometric X-rays. Forty-one, direct-digital lateral cephalometric radiographs were obtained by a Siemens Orthophos DS Ceph and were used in this study and 10 landmarks (N, A Point, Ba, Po, Pt, B Point, Pg, PM, UIE, LIE were the object of automatic landmark identification. The mean errors and standard deviations from the best estimate of cephalometric points were calculated for each landmark. Differences in the mean errors of automatic and manual landmarking were compared with a 1-way analysis of variance. The analyses indicated that the differences were very small, and they were found at most within 0.59?mm. Furthermore, only few of these differences were statistically significant, but differences were so small to be in most instances clinically meaningless. Therefore the use of X-ray files with respect to scanned X-ray improved landmark accuracy of automatic detection. Investigations on softcopy of digital cephalometric X-rays, to search more landmarks in order to enable a complete automatic cephalometric analysis, are strongly encouraged.

  15. Posterior belly of the digastric muscle: An important landmark for various head and neck surgeries

    Directory of Open Access Journals (Sweden)

    Vrinda Hari Ankolekar

    2015-04-01

    Conclusion: As the PBD muscle is an important surgical landmark, the present study adds to the existing knowledge about it. The present study has also included few newer landmarks, which were not given importance in the previous studies. [Arch Clin Exp Surg 2015; 4(2.000: 79-82

  16. Brain Anatomical Network and Intelligence

    OpenAIRE

    Li, Yonghui; Liu, Yong; LI, JUN; Qin, Wen; Li, Kuncheng; Yu, Chunshui; Jiang, Tianzi

    2009-01-01

    Intuitively, higher intelligence might be assumed to correspond to more efficient information transfer in the brain, but no direct evidence has been reported from the perspective of brain networks. In this study, we performed extensive analyses to test the hypothesis that individual differences in intelligence are associated with brain structural organization, and in particular that higher scores on intelligence tests are related to greater global efficiency of the brain anatomical network. W...

  17. Conservation landmarks: bureau of biological survey and national biological service

    Science.gov (United States)

    Friend, M.

    1995-01-01

    A century separates the recent development of the National Biological Service (NBS) and an early predecessor, the Bureau of Biological Survey (BBS). Both organizations were established at critical crossroads for the conservation of the nation's living biological resources and are conservation landmarks of their times. The BBS of the 192()'s was described as 'a government Bureau of the first rank, handling affairs of great scientific, educational, social, and above all, economic importance throughout the United States and its outlying possessions'' (Cameron 1929:144-145). This stature was achieved at a time of great social, economic, and ecological change. BBS had the vision to pioneer new approaches that led to enhanced understanding of the relation between people, other living things, and the environment. The NBS faces similar challenges to address the issues of the 1990's and beyond.

  18. Landmark constrained registration of high-genus surfaces applied to vestibular system morphometry.

    Science.gov (United States)

    Wen, Chengfeng; Wang, Defeng; Shi, Lin; Chu, Winnie C W; Cheng, Jack C Y; Lui, Lok Ming

    2015-09-01

    The analysis of the vestibular system (VS) is an important research topic in medical image analysis. VS is a sensory structure in the inner ear for the perception of spatial orientation. It is believed several diseases, such as the Adolescent Idiopathic Scoliosis (AIS), are due to the impairment of the VS function. The morphology of the VS is thus of great research significance. A major challenge is that the VS is a genus-3 surface. The high-genus topology of the VS poses great challenges to find accurate pointwise correspondences between the surfaces and whereby perform accurate shape analysis. In this paper, we present a method to obtain the landmark constrained diffeomorphic registration between the VS surfaces based on the quasi-conformal theory. Given a set of corresponding landmarks on the VS surfaces, a diffeomorphism between the VS surfaces that matches the features consistently can be obtained. The basic idea is to iteratively search for an admissible Beltrami coefficient, which is associated to our desired landmark matching registration. With the obtained surface registrations, vertex-wise morphometric analysis can be carried out. Two types of geometric features are used for shape comparison. One is the collection of homotopic loops on each canals of the VS, which can be used to measure the local thickness of the canals. From the homotopic loops, centerlines can be extracted. By examining the deviations of the centerlines from the best fit planes, bendings of the canals can be detected. The second geometric feature is the minimal surface enclosed by the homotopic loop. From the minimal surfaces of each homotopic loops, cross-sectional area of the canals can be evaluated. To study the local shape difference more comprehensively, a complete shape index, which is defined using the Beltrami coefficients and surface curvatures, is used. We test proposed registration method on 15 VS of normal control subjects and 12 VS of patients suffering from AIS. Experimental results show the efficacy and accuracy of the proposed algorithm to compute the VS surface registration. Shape analysis has also been carried out using the proposed geometric features and shape index, which reveals shape differences in the posterior canal between normal and diseased AIS groups. PMID:26069905

  19. Parametric Anatomical Modeling: A method for modeling the anatomical layout of neurons and their projections

    Directory of Open Access Journals (Sweden)

    Martin Pyka

    2014-09-01

    Full Text Available Computational models of neural networks can be based on a variety of different parameters. These parameters include, for example, the 3d shape of neuron layers, the neurons' spatial projection patterns, spiking dynamics and neurotransmitter systems. While many well-developed approaches are available to model, for example, the spiking dynamics, there is a lack of approaches for modeling the anatomical layout of neurons and their projections. We present a new method, called Parametric Anatomical Modeling (PAM, to fill this gap. PAM can be used to derive network connectivities and conduction delays from anatomical data, such as the position and shape of the neuronal layers and the dendritic and axonal projection patterns. Within the PAM framework, several mapping techniques between layers can account for a large variety of connection properties between pre- and post-synaptic neuron layers. PAM is implemented as a Python tool and integrated in the 3d modeling software Blender. We demonstrate on a 3d model of the hippocampal formation how PAM can help reveal complex properties of the synaptic connectivity and conduction delays, properties that might be relevant to uncover the function of the hippocampus. Based on these analyses, two experimentally testable predictions arose: i the number of neurons and the spread of connections is heterogeneously distributed across the main anatomical axes, ii the distribution of connection lengths in CA3-CA1 differ qualitatively from those between DG-CA3 and CA3-CA3. Models created by PAM can also serve as an educational tool to visualize the 3d connectivity of brain regions. The low-dimensional, but yet biologically plausible, parameter space renders PAM suitable to analyse allometric and evolutionary factors in networks and to model the complexity of real networks with comparatively little effort.

  20. Parametric Anatomical Modeling: a method for modeling the anatomical layout of neurons and their projections.

    Science.gov (United States)

    Pyka, Martin; Klatt, Sebastian; Cheng, Sen

    2014-01-01

    Computational models of neural networks can be based on a variety of different parameters. These parameters include, for example, the 3d shape of neuron layers, the neurons' spatial projection patterns, spiking dynamics and neurotransmitter systems. While many well-developed approaches are available to model, for example, the spiking dynamics, there is a lack of approaches for modeling the anatomical layout of neurons and their projections. We present a new method, called Parametric Anatomical Modeling (PAM), to fill this gap. PAM can be used to derive network connectivities and conduction delays from anatomical data, such as the position and shape of the neuronal layers and the dendritic and axonal projection patterns. Within the PAM framework, several mapping techniques between layers can account for a large variety of connection properties between pre- and post-synaptic neuron layers. PAM is implemented as a Python tool and integrated in the 3d modeling software Blender. We demonstrate on a 3d model of the hippocampal formation how PAM can help reveal complex properties of the synaptic connectivity and conduction delays, properties that might be relevant to uncover the function of the hippocampus. Based on these analyses, two experimentally testable predictions arose: (i) the number of neurons and the spread of connections is heterogeneously distributed across the main anatomical axes, (ii) the distribution of connection lengths in CA3-CA1 differ qualitatively from those between DG-CA3 and CA3-CA3. Models created by PAM can also serve as an educational tool to visualize the 3d connectivity of brain regions. The low-dimensional, but yet biologically plausible, parameter space renders PAM suitable to analyse allometric and evolutionary factors in networks and to model the complexity of real networks with comparatively little effort. PMID:25309338

  1. Anatomical study of the pigs temporal bone by microdissection

    Scientific Electronic Library Online (English)

    Leandro de Borborema, Garcia; José Santos Cruz de, Andrade; José Ricardo Gurgel, Testa.

    Full Text Available PURPOSE: Initial study of the pig`s temporal bone anatomy in order to enable a new experimental model in ear surgery. METHODS: Dissection of five temporal bones of Sus scrofa pigs obtained from UNIFESP - Surgical Skills Laboratory, removed with hole saw to avoid any injury and stored in formald [...] ehyde 10% for better conservation. The microdissection in all five temporal bone had the following steps: inspection of the outer part, external canal and tympanic membrane microscopy, mastoidectomy, removal of external ear canal and tympanic membrane, inspection of ossicular chain and middle ear. RESULTS: Anatomically it is located at the same position than in humans. Some landmarks usually found in humans are missing. The tympanic membrane of the pig showed to be very similar to the human, separating the external and the middle ear. The middle ear`s appearance is very similar than in humans. The ossicular chain is almost exactly the same, as well as the facial nerve, showing the same relationship with the lateral semicircular canal. CONCLUSION: The temporal bone of the pigs can be used as an alternative for training in ear surgery, especially due the facility to find it and its similarity with temporal bone of the humans.

  2. Anatomical study of the pigs temporal bone by microdissection

    Scientific Electronic Library Online (English)

    Leandro de Borborema, Garcia; José Santos Cruz de, Andrade; José Ricardo Gurgel, Testa.

    Full Text Available PURPOSE: Initial study of the pig`s temporal bone anatomy in order to enable a new experimental model in ear surgery. METHODS: Dissection of five temporal bones of Sus scrofa pigs obtained from UNIFESP - Surgical Skills Laboratory, removed with hole saw to avoid any injury and stored in formal [...] dehyde 10% for better conservation. The microdissection in all five temporal bone had the following steps: inspection of the outer part, external canal and tympanic membrane microscopy, mastoidectomy, removal of external ear canal and tympanic membrane, inspection of ossicular chain and middle ear. RESULTS: Anatomically it is located at the same position than in humans. Some landmarks usually found in humans are missing. The tympanic membrane of the pig showed to be very similar to the human, separating the external and the middle ear. The middle ear`s appearance is very similar than in humans. The ossicular chain is almost exactly the same, as well as the facial nerve, showing the same relationship with the lateral semicircular canal. CONCLUSION: The temporal bone of the pigs can be used as an alternative for training in ear surgery, especially due the facility to find it and its similarity with temporal bone of the humans.

  3. Volume and landmark analysis: comparison of MRI measurements obtained with an endorectal coil and with a phased-array coil

    International Nuclear Information System (INIS)

    Aim: To compare prostate volumes and distances between anatomical landmarks on MRI images obtained with a phased-array coil (PAC) only and with a PAC and an endorectal coil (ERC). Materials and methods: Informed consent was waived for this Health Insurance Portability and Accountability Act-compliant study. Fifty-nine men underwent PAC-MRI and ERC-MRI at 1.5 (n = 3) or 3 T (n = 56). On MRI images, two radiologists independently measured prostate volume and distances between the anterior rectal wall (ARW) and symphysis pubis at the level of the verumontanum; ARW and symphysis pubis at the level of the mid-symphysis pubis; and bladder neck and mid-symphysis pubis. Differences between measurements from PAC-MRI and ERC-MRI were assessed with the Wilcoxon RANK SUM test. Inter-reader agreement was assessed using the concordance correlation coefficient (CCC). Results: Differences in prostate volume between PAC-MRI and ERC-MRI [median: ?0.75 mm3 (p = 0.10) and median: ?0.84 mm3 (p = 0.06) for readers 1 and 2, respectively] were not significant. For readers 1 and 2, median differences between distances were as follows: ?10.20 and ?12.75 mm, respectively, ARW to symphysis pubis at the level of the verumontanum; ?6.60 and ?6.08 mm, respectively, ARW to symphysis pubis at the level of the mid-symphysis pubis; ?3 and ?3 mm respectively, bladder neck to mid-symphysis pubis. All differences in distance were significant for both readers (p ? 0.0005). Distances were larger on PAC-MRI (p ? 0.0005). Inter-reader agreement regarding prostate volume was almost perfect on PAC-MRI (CCC: 0.99; 95% CI: 0.98–1.00) and ERC-MRI (CCC: 0.99; 95% CI: 0.99–1.00); inter-reader agreement for distance measurements varied (CCCs: 0.54–0.86). Conclusion: Measurements of distances between anatomical landmarks differed significantly between ERC-MRI and PAC-MRI, although prostate volume measurements did not. - Highlights: • Measurements of prostate geometry are compared on MRI with two coil arrangements. • Prostate volume did not differ significantly between the two coil arrangements. • Distances differed significantly between the two coil arrangements

  4. A FastSLAM-based algorithm for omnidirectional cameras

    OpenAIRE

    Cristina Gamallo; Manuel Mucientes; Regueiro, Carlos V.

    2013-01-01

    Environments with a low density of landmarks are difficult for vision-based Simultaneous Localization and Mapping (SLAM) algorithms. The use of omnidirectional cameras, which have a wide field of view, is specially interesting in these environments as several landmarks are usually detected in each image. A typical example of this kind of situation happens in indoor environments when the lights placed on the ceiling are the landmarks. The use of omnivision combined with this type of landmarks ...

  5. TOPICAL REVIEW: Anatomical imaging for radiotherapy

    Science.gov (United States)

    Evans, Philip M.

    2008-06-01

    The goal of radiation therapy is to achieve maximal therapeutic benefit expressed in terms of a high probability of local control of disease with minimal side effects. Physically this often equates to the delivery of a high dose of radiation to the tumour or target region whilst maintaining an acceptably low dose to other tissues, particularly those adjacent to the target. Techniques such as intensity modulated radiotherapy (IMRT), stereotactic radiosurgery and computer planned brachytherapy provide the means to calculate the radiation dose delivery to achieve the desired dose distribution. Imaging is an essential tool in all state of the art planning and delivery techniques: (i) to enable planning of the desired treatment, (ii) to verify the treatment is delivered as planned and (iii) to follow-up treatment outcome to monitor that the treatment has had the desired effect. Clinical imaging techniques can be loosely classified into anatomic methods which measure the basic physical characteristics of tissue such as their density and biological imaging techniques which measure functional characteristics such as metabolism. In this review we consider anatomical imaging techniques. Biological imaging is considered in another article. Anatomical imaging is generally used for goals (i) and (ii) above. Computed tomography (CT) has been the mainstay of anatomical treatment planning for many years, enabling some delineation of soft tissue as well as radiation attenuation estimation for dose prediction. Magnetic resonance imaging is fast becoming widespread alongside CT, enabling superior soft-tissue visualization. Traditionally scanning for treatment planning has relied on the use of a single snapshot scan. Recent years have seen the development of techniques such as 4D CT and adaptive radiotherapy (ART). In 4D CT raw data are encoded with phase information and reconstructed to yield a set of scans detailing motion through the breathing, or cardiac, cycle. In ART a set of scans is taken on different days. Both allow planning to account for variability intrinsic to the patient. Treatment verification has been carried out using a variety of technologies including: MV portal imaging, kV portal/fluoroscopy, MVCT, conebeam kVCT, ultrasound and optical surface imaging. The various methods have their pros and cons. The four x-ray methods involve an extra radiation dose to normal tissue. The portal methods may not generally be used to visualize soft tissue, consequently they are often used in conjunction with implanted fiducial markers. The two CT-based methods allow measurement of inter-fraction variation only. Ultrasound allows soft-tissue measurement with zero dose but requires skilled interpretation, and there is evidence of systematic differences between ultrasound and other data sources, perhaps due to the effects of the probe pressure. Optical imaging also involves zero dose but requires good correlation between the target and the external measurement and thus is often used in conjunction with an x-ray method. The use of anatomical imaging in radiotherapy allows treatment uncertainties to be determined. These include errors between the mean position at treatment and that at planning (the systematic error) and the day-to-day variation in treatment set-up (the random error). Positional variations may also be categorized in terms of inter- and intra-fraction errors. Various empirical treatment margin formulae and intervention approaches exist to determine the optimum strategies for treatment in the presence of these known errors. Other methods exist to try to minimize error margins drastically including the currently available breath-hold techniques and the tracking methods which are largely in development. This paper will review anatomical imaging techniques in radiotherapy and how they are used to boost the therapeutic benefit of the treatment.

  6. A hierarchical scheme for geodesic anatomical labeling of airway trees

    DEFF Research Database (Denmark)

    Feragen, Aasa; Petersen, Jens; Owen, Megan; Lo, Pechin Chien Pau; Thomsen, Laura; Wille, Mathilde; Dirksen, Asger; de Bruijne, Marleen

    We present a fast and robust supervised algorithm for label- ing anatomical airway trees, based on geodesic distances in a geometric tree-space. Possible branch label configurations for a given unlabeled air- way tree are evaluated based on the distances to a training set of labeled airway trees....

  7. Robust Morphological Averages in Three Dimensions for Anatomical Atlas Construction

    Science.gov (United States)

    Márquez, Jorge; Bloch, Isabelle; Schmitt, Francis

    2004-09-01

    We present original methods for obtaining robust, anatomical shape-based averages of features of the human head anatomy from a normal population. Our goals are computerized atlas construction with representative anatomical features and morphopometry for specific populations. A method for true-morphological averaging is proposed, consisting of a suitable blend of shape-related information for N objects to obtain a progressive average. It is made robust by penalizing, in a morphological sense, the contributions of features less similar to the current average. Morphological error and similarity, as well as penalization, are based on the same paradigm as the morphological averaging.

  8. Technical Note: Anatomic identification of isolated modern human molars: testing Procrustes aligned outlines as a standardization procedure for elliptic fourier analysis.

    Science.gov (United States)

    Corny, Julien; Détroit, Florent

    2014-02-01

    The determination of the precise position of permanent first and second modern human molars, following standard tooth identification criteria, is often difficult because of their morphological similarities. Here, we proposed to evaluate the suitability of two-dimensional crown contour shape analysis in achieving this objective. The method was tested separately on 180 first and second maxillary molars (UM) and 180 first and second mandibular molars (LM) securely identified (in anatomical position in their sockets). Generalized Procrustes superimposition is used to normalize the outlines prior to applying elliptic Fourier analyses ("EFAproc" method). Reliability and effectiveness of this morphometric procedure was evaluated by comparing the results obtained for the same dataset with four other morphometric methods of contour analysis. Cross-validated ("leave one individual out") percentages of misclassification yielded by linear discriminant analyses were used for determining the anatomic position of modern human molars. The percentages of misclassifications obtained from every method of contour analysis were low (1.67% to 3.33% for the UM, 5.56% to 6.67% for the LM) indicating the high suitability of crown contour analyses in correctly identifying molars. A reliable protocol, based on predictive linear discriminant analyses, was then proposed for identification of isolated molars. In addition, our results confirmed that the EFAproc method is suitable for normalizing outlines prior to undertaking elliptic Fourier analyses, especially in the case of nearly circular outlines: it obtained better classification than the classic method of normalization of Fourier descriptors for UM and provided also some advantages over the three landmarks-based methods tested here. PMID:24242977

  9. Landmark constrained genus-one surface Teichmüller map applied to surface registration in medical imaging.

    Science.gov (United States)

    Lam, Ka Chun; Gu, Xianfeng; Lui, Lok Ming

    2015-10-01

    We address the registration problem of genus-one surfaces (such as vertebrae bones) with prescribed landmark constraints. The high-genus topology of the surfaces makes it challenging to obtain a unique and bijective surface mapping that matches landmarks consistently. This work proposes to tackle this registration problem using a special class of quasi-conformal maps called Teichmüller maps (T-Maps). A landmark constrained T-Map is the unique mapping between genus-1 surfaces that minimizes the maximal conformality distortion while matching the prescribed feature landmarks. Existence and uniqueness of the landmark constrained T-Map are theoretically guaranteed. This work presents an iterative algorithm to compute the T-Map. The main idea is to represent the set of diffeomorphism using the Beltrami coefficients (BC). The BC is iteratively adjusted to an optimal one, which corresponds to our desired T-Map that matches the prescribed landmarks and satisfies the periodic boundary condition on the universal covering space. Numerical experiments demonstrate the effectiveness of our proposed algorithm. The method has also been applied to register vertebrae bones with prescribed landmark points and curves, which gives accurate surface registrations. PMID:25977154

  10. Anatomic variability of groin innervation.

    Science.gov (United States)

    Bachul, P; Tomaszewski, K A; Kmiotek, E K; Kratochwil, M; Solecki, R; Walocha, J A

    2013-08-01

    Inguinal hernia repairs are very common yet fairly complex surgical procedures.Variations in the anatomical course of the inguinal nerves require that diligence is taken in their proper recognition. Inadvertent surgical injury to these nerves is associated with long term postoperative pain and complications. The aim of the present study was to highlight the complexity and variation in the innervation of the inguinal region in order to increase proper nerve identification during surgical interventions. Bilateral dissection of the inguinal and posterior abdominal regions in one human male cadaver revealed an atypical anatomic topography of the groin innervation. This unusual case was observed at the Jagiellonian University Anatomy Department during routine cadaveric preparations. The left ilioinguinal nerve was absent. The left genital branch of the genitofemoral nerve arose higher than expected from the lumbar plexus and supplied the groin region, which is typically innervated by the ilioinguinal nerve. Furthermore, the left lateral cutaneous femoral nerve and the right genital branch of the genitofemoral nerve also followed uncharacteristic courses. Awareness of topographical nerve variations during inguinal hernia repair will help surgeons identify and preserve important nerves, thus decreasing the incidence of chronic postoperative pain. PMID:24068690

  11. Developing an anatomical model of the human laryngeal cartilages from magnetic resonance imaging.

    Science.gov (United States)

    Selbie, W Scott; Gewalt, Sally L; Ludlow, Christy L

    2002-09-01

    The purpose of this work was to construct a three-dimensional anatomical framework of the cartilages of the human larynx. The framework included representative surface models of the four laryngeal cartilages and estimated attachment points for the intrinsic laryngeal muscles. High-resolution magnetic resonance imaging (MRI) was used to scan one female and four male human cadaveric larynges. The cartilages were segmented manually from the MRI volume for analysis. Two of these larynges were subsequently dissected and the landmark distances on the cartilages measured for comparison with the MRI measures and previous studies. The MRI measures were 8% smaller than the anatomical measures and 12% smaller than data reported in the literature. A laryngeal coordinate system was defined using the plane of symmetry of the cricoid cartilage. Measures of cricoid cartilage symmetry had less than 3% difference between the two sides for a series of measures. An algorithm for registering larynges that minimized the root-mean-square distance between the surface of a reference cricoid cartilage and the surfaces of nonisotropically scaled candidate cricoid cartilages was evaluated. This study provided an anatomical framework for registering different larynges to the same coordinate space. PMID:12243156

  12. Dosimetric accuracy of a deterministic radiation transport based {sup 192}Ir brachytherapy treatment planning system. Part III. Comparison to Monte Carlo simulation in voxelized anatomical computational models

    Energy Technology Data Exchange (ETDEWEB)

    Zourari, K.; Pantelis, E.; Moutsatsos, A.; Sakelliou, L.; Georgiou, E.; Karaiskos, P.; Papagiannis, P. [Medical Physics Laboratory, Medical School, University of Athens, 75 Mikras Asias, 115 27 Athens (Greece); Department of Physics, Nuclear and Particle Physics Section, University of Athens, Ilisia, 157 71 Athens (Greece); Medical Physics Laboratory, Medical School, University of Athens, 75 Mikras Asias, 115 27 Athens (Greece)

    2013-01-15

    Purpose: To compare TG43-based and Acuros deterministic radiation transport-based calculations of the BrachyVision treatment planning system (TPS) with corresponding Monte Carlo (MC) simulation results in heterogeneous patient geometries, in order to validate Acuros and quantify the accuracy improvement it marks relative to TG43. Methods: Dosimetric comparisons in the form of isodose lines, percentage dose difference maps, and dose volume histogram results were performed for two voxelized mathematical models resembling an esophageal and a breast brachytherapy patient, as well as an actual breast brachytherapy patient model. The mathematical models were converted to digital imaging and communications in medicine (DICOM) image series for input to the TPS. The MCNP5 v.1.40 general-purpose simulation code input files for each model were prepared using information derived from the corresponding DICOM RT exports from the TPS. Results: Comparisons of MC and TG43 results in all models showed significant differences, as reported previously in the literature and expected from the inability of the TG43 based algorithm to account for heterogeneities and model specific scatter conditions. A close agreement was observed between MC and Acuros results in all models except for a limited number of points that lay in the penumbra of perfectly shaped structures in the esophageal model, or at distances very close to the catheters in all models. Conclusions: Acuros marks a significant dosimetry improvement relative to TG43. The assessment of the clinical significance of this accuracy improvement requires further work. Mathematical patient equivalent models and models prepared from actual patient CT series are useful complementary tools in the methodology outlined in this series of works for the benchmarking of any advanced dose calculation algorithm beyond TG43.

  13. Dosimetric accuracy of a deterministic radiation transport based 192Ir brachytherapy treatment planning system. Part III. Comparison to Monte Carlo simulation in voxelized anatomical computational models

    International Nuclear Information System (INIS)

    Purpose: To compare TG43-based and Acuros deterministic radiation transport-based calculations of the BrachyVision treatment planning system (TPS) with corresponding Monte Carlo (MC) simulation results in heterogeneous patient geometries, in order to validate Acuros and quantify the accuracy improvement it marks relative to TG43. Methods: Dosimetric comparisons in the form of isodose lines, percentage dose difference maps, and dose volume histogram results were performed for two voxelized mathematical models resembling an esophageal and a breast brachytherapy patient, as well as an actual breast brachytherapy patient model. The mathematical models were converted to digital imaging and communications in medicine (DICOM) image series for input to the TPS. The MCNP5 v.1.40 general-purpose simulation code input files for each model were prepared using information derived from the corresponding DICOM RT exports from the TPS. Results: Comparisons of MC and TG43 results in all models showed significant differences, as reported previously in the literature and expected from the inability of the TG43 based algorithm to account for heterogeneities and model specific scatter conditions. A close agreement was observed between MC and Acuros results in all models except for a limited number of points that lay in the penumbra of perfectly shaped structures in the esophageal model, or at distances very close to the catheters in all models. Conclusions: Acuros marks a significant dosimetry improvement relative to TG43. The assessment of the clinical significance of this accuracy improvement requires further work. Mathematical patient equivalent models and models prepared from actual patient CT series are useful complementary tools in the methodology outlined in this series of works for the benchmarking of any advanced dose calculation algorithm beyond TG43.

  14. Generalized multiresolution hierarchical shape models via automatic landmark clusterization.

    Science.gov (United States)

    Cerrolaza, Juan J; Villanueva, Arantxa; Reyes, Mauricio; Cabeza, Rafael; González Ballester, Miguel Angel; Linguraru, Marius George

    2014-01-01

    Point Distribution Models (PDM) are some of the most popular shape description techniques in medical imaging. However, to create an accurate shape model it is essential to have a representative sample of the underlying population, which is often challenging. This problem is particularly relevant as the dimensionality of the modeled structures increases, and becomes critical when dealing with complex 3D shapes. In this paper, we introduce a new generalized multiresolution hierarchical PDM (GMRH-PDM) able to efficiently address the high-dimension-low-sample-size challenge when modeling complex structures. Unlike previous approaches, our new and general framework extends hierarchical modeling to any type of structure (multi- and single-object shapes) allowing to describe efficiently the shape variability at different levels of resolution. Importantly, the configuration of the algorithm is automatized thanks to the new agglomerative landmark clustering method presented here. Our new and automatic GMRH-PDM framework performed significantly better than classical approaches, and as well as the state-of-the-art with the best manual configuration. Evaluations have been studied for two different cases, the right kidney, and a multi-object case composed of eight subcortical structures. PMID:25320775

  15. Landmark-free geometric methods in biological shape analysis.

    Science.gov (United States)

    Koehl, Patrice; Hass, Joel

    2015-12-01

    In this paper, we propose a new approach for computing a distance between two shapes embedded in three-dimensional space. We take as input a pair of triangulated genus zero surfaces that are topologically equivalent to spheres with no holes or handles, and construct a discrete conformal map f between the surfaces. The conformal map is chosen to minimize a symmetric deformation energy Esd(f) which we introduce. This measures the distance of f from an isometry, i.e. a non-distorting correspondence. We show that the energy of the minimizing map gives a well-behaved metric on the space of genus zero surfaces. In contrast to most methods in this field, our approach does not rely on any assignment of landmarks on the two surfaces. We illustrate applications of our approach to geometric morphometrics using three datasets representing the bones and teeth of primates. Experiments on these datasets show that our approach performs remarkably well both in shape recognition and in identifying evolutionary patterns, with success rates similar to, and in some cases better than, those obtained by expert observers. PMID:26631331

  16. Evaluation of contrast reproduction method based on the anatomical guidance of the cerebral images reconstruction in positron emission tomography; Evaluation d'une methode de restitution de contraste basee sur le guidage anatomique de la reconstruction des images cerebrales en tomographie par emission de positons

    Energy Technology Data Exchange (ETDEWEB)

    Bataille, F

    2007-04-15

    Positron emission tomography is a medical imaging modality providing in-vivo volumetric images of functional processes of the human body, which is used for the diagnosis and the following of neuro degenerative diseases. PET efficiency is however limited by its poor spatial resolution, which generates a decrease of the image local contrast and leads to an under-estimation of small cerebral structures involved in the degenerative mechanism of those diseases. This so-called partial volume effect degradation is usually corrected in a post-reconstruction processing framework through the use of anatomical information, whose spatial resolution allows a better discrimination between functional tissues. However, this kind of method has the major drawback of being very sensitive to the residual mismatches on the anatomical information processing. We developed in this thesis an alternative methodology to compensate for the degradation, by incorporating in the reconstruction process both a model of the system impulse response and an anatomically-based image prior constraint. This methodology was validated by comparison with a post-reconstruction correction strategy, using data from an anthropomorphic phantom acquisition and then we evaluated its robustness to the residual mismatches through a realistic Monte Carlo simulation corresponding to a cerebral exam. The proposed algorithm was finally applied to clinical data reconstruction. (author)

  17. 77 FR 44670 - Information Collection Activities: National Historic Landmarks (NHL) Condition Survey

    Science.gov (United States)

    2012-07-30

    ...regarding the condition of designated landmarks. A questionnaire will be designed and used to collect information...condition data. Regional NPS staff contributed to the design of the questionnaire that is the subject of this request. II....

  18. Landmark discrimination learning in the dog: effects of age, an antioxidant fortified food, and cognitive strategy.

    Science.gov (United States)

    Milgram, Norton W; Head, E; Muggenburg, B; Holowachuk, D; Murphey, H; Estrada, J; Ikeda-Douglas, C J; Zicker, S C; Cotman, C W

    2002-10-01

    The landmark discrimination learning test can be used to assess the ability to utilize allocentric spatial information to locate targets. The present experiments examined the role of various factors on performance of a landmark discrimination learning task in beagle dogs. Experiments 1 and 2 looked at the effects of age and food composition. Experiments 3 and 4 were aimed at characterizing the cognitive strategies used in performance on this task and in long-term retention. Cognitively equivalent groups of old and young dogs were placed into either a test group maintained on food enriched with a broad-spectrum of antioxidants and mitochondrial cofactors, or a control group maintained on a complete and balanced food formulated for adult dogs. Following a wash-in period, the dogs were tested on a series of problems, in which reward was obtained when the animal responded selectively to the object closest to a thin wooden block, which served as a landmark. In Experiment 1, dogs were first trained to respond to a landmark placed directly on top of coaster, landmark 0 (L0). In the next phase of testing, the landmark was moved at successively greater distances (1, 4 or 10 cm) away from the reward object. Learning varied as a function of age group, food group, and task. The young dogs learned all of the tasks more quickly than the old dogs. The aged dogs on the enriched food learned L0 significantly more rapidly than aged dogs on control food. A higher proportion of dogs on the enriched food learned the task, when the distance was increased to 1cm. Experiment 2 showed that accuracy decreased with increased distance between the reward object and landmark, and this effect was greater in old animals. Experiment 3 showed stability of performance, despite using a novel landmark, and new locations, indicating that dogs learned the landmark concept. Experiment 4 found age impaired long-term retention of the landmark task. These results indicate that allocentric spatial learning is impaired in an age-dependent manner in dogs, and that age also affects performance when the distance between the landmark and target is increased. In addition, these results both support a role of oxidative damage in the development of age-associated cognitive dysfunction and indicate that short-term administration of a food enriched with supplemental antioxidants and mitochondrial cofactors can partially reverse the deleterious effects of aging on cognition. PMID:12479842

  19. Interspecific differences in response to novel landmarks in bumblebees (Bombus sp.)

    OpenAIRE

    Goulson, Dave; Darvill, Ben; Ellis, Jon; Knight, Mairi; Hanley, Mick

    2004-01-01

    We provide evidence for interspecific differences in the behaviour of bumblebees which suggests that there may be important differences in the way that they navigate. Bumblebees commonly investigate the novel landmark presented by a human standing in open countryside. When doing so they perform a characteristic flight similar to that observed when a naïve bee first leaves the nest, suggesting that they are memorising the location of an unfamiliar landmark. We compare the frequency with which ...

  20. Effects of image enhancement on reliability of landmark identification in digital cephalometry

    Directory of Open Access Journals (Sweden)

    M Oshagh

    2013-01-01

    Full Text Available Introduction: Although digital cephalometric radiography is gaining popularity in orthodontic practice, the most important source of error in its tracing is uncertainty in landmark identification. Therefore, efforts to improve accuracy in landmark identification were directed primarily toward the improvement in image quality. One of the more useful techniques of this process involves digital image enhancement which can increase overall visual quality of image, but this does not necessarily mean a better identification of landmarks. The purpose of this study was to evaluate the effectiveness of digital image enhancements on reliability of landmark identification. Materials and Methods: Fifteen common landmarks including 10 skeletal and 5 soft tissues were selected on the cephalograms of 20 randomly selected patients, prepared in Natural Head Position (NHP. Two observers (orthodontists identified landmarks on the 20 original photostimulable phosphor (PSP digital cephalogram images and 20 enhanced digital images twice with an intervening time interval of at least 4 weeks. The x and y coordinates were further analyzed to evaluate the pattern of recording differences in horizontal and vertical directions. Reliability of landmarks identification was analyzed by paired t test. Results: There was a significant difference between original and enhanced digital images in terms of reliability of points Ar and N in vertical and horizontal dimensions, and enhanced images were significantly more reliable than original images. Identification of A point, Pogonion and Pronasal points, in vertical dimension of enhanced images was significantly more reliable than original ones. Reliability of Menton point identification in horizontal dimension was significantly more in enhanced images than original ones. Conclusion: Direct digital image enhancement by altering brightness and contrast can increase reliability of some landmark identification and this may lead to more accurate cephalometric analysis.

  1. Learning Compact Visual Descriptors for Low Bit Rate Mobile Landmark Search

    OpenAIRE

    Duan, Ling-Yu; Peking University; Chen, Jie; Peking University; Ji, Rongrong; Peking University; Huang, Tiejun; Peking University; Gao, Wen; Peking University

    2013-01-01

    Coming with the ever growing computational power of mobile devices, mobile visual search have undergone an evolution in techniques and applications. A significant trend is low bit rate visual search, where compact visual descriptors are extracted directly over a mobile and delivered as queries rather than raw images to reduce the query transmission latency. In this article, we introduce our work on low bit rate mobile landmark search, in which a compact yet discriminative landmark image descr...

  2. An Evaluation of Cellular Neural Networks for the Automatic Identification of Cephalometric Landmarks on Digital Images

    OpenAIRE

    Rosalia Leonardi; Daniela Giordano; Francesco Maiorana

    2009-01-01

    Several efforts have been made to completely automate cephalometric analysis by automatic landmark search. However, accuracy obtained was worse than manual identification in every study. The analogue-to-digital conversion of X-ray has been claimed to be the main problem. Therefore the aim of this investigation was to evaluate the accuracy of the Cellular Neural Networks approach for automatic location of cephalometric landmarks on softcopy of direct digital cephalometric X-rays. Forty-one, di...

  3. Detection of New Genomic Landmarks in the Maltese Goat Using Rapd PCR

    OpenAIRE

    Blundell, R.; A.E. Felice

    2006-01-01

    Since no information of the Maltese goat genome is available, RAPD technique has been used to identify a number of DNA landmarks. Genome Landmarks have been obtained from the DNA of 66 Maltese goats which were studied with Random Amplification of Polymorphic DNA (RAPD). Eleven (11) reproducible RAPD polymorphic zones were identified. For sequencing, the RAPD zones were cloned into the Puc 18 vector utilising E. coli and then sequenced using both the forward (universal) and reverse primers spe...

  4. A method based on Monte Carlo simulations and voxelized anatomical atlases to evaluate and correct uncertainties on radiotracer accumulation quantitation in beta microprobe studies in the rat brain

    International Nuclear Information System (INIS)

    The ?-microprobe is a simple and versatile technique complementary to small animal positron emission tomography (PET). It relies on local measurements of the concentration of positron-labeled molecules. So far, it has been successfully used in anesthetized rats for pharmacokinetics experiments and for the study of brain energetic metabolism. However, the ability of the technique to provide accurate quantitative measurements using 18F, 11C and 15O tracers is likely to suffer from the contribution of 511 keV gamma rays background to the signal and from the contribution of positrons from brain loci surrounding the locus of interest. The aim of the present paper is to provide a method of evaluating several parameters, which are supposed to affect the quantification of recordings performed in vivo with this methodology. We have developed realistic voxelized phantoms of the rat whole body and brain, and used them as input geometries for Monte Carlo simulations of previous ?-microprobe reports. In the context of realistic experiments (binding of 11C-Raclopride to D2 dopaminergic receptors in the striatum; local glucose metabolic rate measurement with 18F-FDG and H2O15 blood flow measurements in the somatosensory cortex), we have calculated the detection efficiencies and corresponding contribution of 511 keV gammas from peripheral organs accumulation. We confirmed that the 511 keV gammas background does not impair quantification. To evaluate the contribution of positrons from adjacent structures, we have developed ?-Assistant, a program based on a rat brain voxelized atlas and matrices of local detection efficiencies calculated by Monte Carlo simulations for several probe geometries. This program was used to calculate the 'apparent sensitivity' of the probe for each brain structure included in the detection volume. For a given localization of a probe within the brain, this allows us to quantify the different sources of beta signal. Finally, since stereotaxic accuracy is crucial for quantification in most microprobe studies, the influence of stereotaxic positioning error was studied for several realistic experiments in favorable and unfavorable experimental situations (binding of 11C-Raclopride to D2 dopaminergic receptors in the striatum; binding of 18F-MPPF to 5HT1A receptors in the dorsal raphe nucleus)

  5. A method based on Monte Carlo simulations and voxelized anatomical atlases to evaluate and correct uncertainties on radiotracer accumulation quantitation in beta microprobe studies in the rat brain

    Energy Technology Data Exchange (ETDEWEB)

    Pain, F; Dhenain, M; Gurden, H; Routier, A L; Lefebvre, F; Mastrippolito, R; Laniece, P [UMR8165 Imagerie et Modelisation en Cancerologie et Neurobiologie, Universites Paris 11/Paris 7, Campus d' Orsay Bat 104/440 91406 Orsay Cedex (France)

    2008-10-07

    The {beta}-microprobe is a simple and versatile technique complementary to small animal positron emission tomography (PET). It relies on local measurements of the concentration of positron-labeled molecules. So far, it has been successfully used in anesthetized rats for pharmacokinetics experiments and for the study of brain energetic metabolism. However, the ability of the technique to provide accurate quantitative measurements using {sup 18}F, {sup 11}C and {sup 15}O tracers is likely to suffer from the contribution of 511 keV gamma rays background to the signal and from the contribution of positrons from brain loci surrounding the locus of interest. The aim of the present paper is to provide a method of evaluating several parameters, which are supposed to affect the quantification of recordings performed in vivo with this methodology. We have developed realistic voxelized phantoms of the rat whole body and brain, and used them as input geometries for Monte Carlo simulations of previous {beta}-microprobe reports. In the context of realistic experiments (binding of {sup 11}C-Raclopride to D2 dopaminergic receptors in the striatum; local glucose metabolic rate measurement with {sup 18}F-FDG and H{sub 2}O{sup 15} blood flow measurements in the somatosensory cortex), we have calculated the detection efficiencies and corresponding contribution of 511 keV gammas from peripheral organs accumulation. We confirmed that the 511 keV gammas background does not impair quantification. To evaluate the contribution of positrons from adjacent structures, we have developed {beta}-Assistant, a program based on a rat brain voxelized atlas and matrices of local detection efficiencies calculated by Monte Carlo simulations for several probe geometries. This program was used to calculate the 'apparent sensitivity' of the probe for each brain structure included in the detection volume. For a given localization of a probe within the brain, this allows us to quantify the different sources of beta signal. Finally, since stereotaxic accuracy is crucial for quantification in most microprobe studies, the influence of stereotaxic positioning error was studied for several realistic experiments in favorable and unfavorable experimental situations (binding of {sup 11}C-Raclopride to D2 dopaminergic receptors in the striatum; binding of {sup 18}F-MPPF to 5HT1A receptors in the dorsal raphe nucleus)

  6. Bases anatômicas para utilização do músculo fibular terceiro em retalhos miocutâneos / Anatomical basis for the use of the fibularis tertius muscle in myocutaneous flaps

    Scientific Electronic Library Online (English)

    Luiz Carlos Buarque de, Gusmão; Jacqueline Silva Brito, Lima; Felipe Henning Gaia, Duarte; Anderson Gonçalves de Farias, Souto; Bruno de Melo Veloso, Couto.

    2013-06-01

    Full Text Available INTRODUÇÃO: A utilização de retalhos miocutâneos é cada dia mais frequente nas cirurgias plásticas reconstrutoras de membros inferiores, tornando-se essencial a utilização de músculos que denotem menor prejuízo tanto funcional como estético. Foram estudados a frequência e os aspectos anatômicos do m [...] úsculo fibular terceiro, com o intuito de avaliar, sob esses aspectos, a possibilidade de seu uso nesses procedimentos. MÉTODO: Foram dissecados 64 membros inferiores de cadáveres fixados e verificadas as seguintes características: inserção proximal, inserção distal, sintopia, morfologia e morfometria. RESULTADOS: A presença do músculo foi constatada em 96,9% dos casos, sendo analisados os aspectos supracitados. A inserção proximal mais frequente (96,8%) ocorreu na membrana interóssea, na margem anterior da fíbula, e no septo intermuscular anterior. A inserção distal mais comum (77,4%) foi nas faces dorsal e lateral do 5º metatarsiano. O valor médio do comprimento e da largura do ventre muscular foi, respectivamente, de 17,89 cm e 1,95 cm, enquanto a média do comprimento do tendão distal livre de fibras musculares foi de 1,2 cm e a largura média do tendão distal, de 0,45 cm. CONCLUSÕES: O músculo fibular terceiro é frequente, de morfologia distinta, que, sob aspectos morfométricos, se constitui em opção viável para um estudo mais específico de seu uso no reparo de defeitos no segmento distal do membro inferior. Abstract in english BACKGROUND: Myocutaneous flaps have been increasingly used in surgical reconstruction of the lower limbs, requiring the use of muscles that result in less functional and esthetic damage as flaps. This study aimed to evaluate the use of the fibularis tertius muscle (in terms of frequency and anatomy) [...] as flaps in this procedure. METHODS: Sixty-four lower limbs from preserved cadavers were dissected and evaluated based on the following parameters: proximal insertion, distal insertion, syntopy, morphology, and morphometry. RESULTS: The fibularis tertius muscle was detected in 96.9% of the study cases. Most proximal insertions (96.8%) were found at the interosseous membrane, anterior border of the fibula, and anterior intermuscular septum. Most distal insertions (77.4%) were found at the lateral and dorsal sides of the 5th metatarsal. Mean value of muscle belly length was 17.89 cm and width was 1.95 cm. The mean length of the distal tendon with no muscle fibers was 1.2 cm, and the mean width was 0.45 cm. CONCLUSIONS: The fibularis tertius muscle is frequent and has a distinct morphology, making it a viable option for the repair of lower limb (distal segment) defects.

  7. An Effect of Landmarks on Territory Shape in a Convict Cichlid.

    Science.gov (United States)

    Mesterton-Gibbons, Mike; Dai, Yao

    2015-12-01

    We determine size, shape and location for a territory that is optimal in the sense of minimizing defense costs, when a given proportion of the boundary is landmarked and its primary benefit in terms of fitness is greater ease of detecting intruders across it. Increasing the landmarked proportion of boundary causes the optimal configuration to be smaller and more elongated, and to be located with its center further from the nest, so that the nest is closer to the landmarked boundary. These predictions accord with observations in a recent study of the convict cichlid Amatitlania siquia. Our results thus confirm the consistency of the observed behavior with the hypothesis that A. siquia designs its territory to make intruders easier to spot. Our results also lead us to conjecture that moving the landmark proportionately closer to or further away from the nest would have yielded essentially the same outcome in this study, because the optimal configuration depends only on the angle subtended by the landmark at the nest and hence only on the length of the landmark relative to its distance from the nest, as opposed to its absolute value. PMID:26621358

  8. Configurational salience of landmarks: an analysis of sketch maps using Space Syntax.

    Science.gov (United States)

    von Stülpnagel, Rul; Frankenstein, Julia

    2015-09-01

    We conducted a visibility graph analysis (a Space Syntax method) of a virtual environment to examine how the configurational salience of global and local landmarks (i.e., their relative positions in the environment) as compared to their visual salience affects the probability of their depiction on sketch maps. Participants of two experimental conditions produced sketch maps from memory after exploration with a layout map or without a map, respectively. Participants of a third condition produced sketch maps in parallel to exploration. More detailed sketch maps were produced in the third condition, but landmarks with higher configurational salience were depicted more frequently across all experimental conditions. Whereas the inclusion of global landmarks onto sketch maps was best predicted by their size, both visual salience and isovist size (i.e., the area a landmark was visible from) predicted the frequency of depiction for local landmarks. Our findings imply that people determine the relevance of landmarks not only by their visual, but even more by their configurational salience. PMID:26239756

  9. Ultrasound Guided Internal Jugular Venous Cannulation: Comparison with Land-Mark Technique

    International Nuclear Information System (INIS)

    Objective: To compare real-time ultrasonography-guided technique versus the traditional land-mark technique for internal Jugular venous cannulation. Study Design: Randomized controlled trial. Place and Duration of Study: Department of Anaesthesia, Combined Military Hospital, Rawalpindi, from September 2013 to July 2014. Methodology:Atotal of 200 patients who required internal jugular vein cannulation were randomly assigned using either real-time ultrasound-guided technique or land-mark technique. Access time, number of attempts until successful cannulation, complications and the demographics of each patient were recorded. Results:Access time was significantly less in real-time ultrasound group (34.95 ± 11.47 vs. 146.59 ± 40.20 seconds, p < 0.001). Cannulation was performed in first attempt in 99 percentage of patients in ultrasound group as compared to 89 percentage of landmark group. Complication rate was significantly higher in the land-mark group than in the ultrasound-guided group. Carotid artery puncture rate (9 percentage vs. 1 percentage) and haematoma formation (7 percentage vs. 0 percentage) were more frequent in the land-mark group than in the ultrasound-guided group. Brachial plexus irritation was also more in land-mark group (6 percentage vs. 0 percentage). Conclusion:Access time, failure rate and procedure related complications are reduced when real-time ultrasonography is used to cannulate internal Jugular vein. (author)

  10. How you get there from here: interaction of visual landmarks and path integration in human navigation.

    Science.gov (United States)

    Zhao, Mintao; Warren, William H

    2015-06-01

    How do people combine their sense of direction with their use of visual landmarks during navigation? Cue-integration theory predicts that such cues will be optimally integrated to reduce variability, whereas cue-competition theory predicts that one cue will dominate the response direction. We tested these theories by measuring both accuracy and variability in a homing task while manipulating information about path integration and visual landmarks. We found that the two cues were near-optimally integrated to reduce variability, even when landmarks were shifted up to 90°. Yet the homing direction was dominated by a single cue, which switched from landmarks to path integration when landmark shifts were greater than 90°. These findings suggest that cue integration and cue competition govern different aspects of the homing response: Cues are integrated to reduce response variability but compete to determine the response direction. The results are remarkably similar to data on animal navigation, which implies that visual landmarks reset the orientation, but not the precision, of the path-integration system. PMID:25944773

  11. Reliability and reproducibility of three-dimensional cephalometric landmarks using CBCT: a systematic review

    Scientific Electronic Library Online (English)

    Cinthia de Oliveira, LISBOA; Daniele, MASTERSON; Andréa Fonseca Jardim, MOTTA; Alexandre Trindade, MOTTA.

    2015-04-01

    Full Text Available Objective : The aim of this study was to review the reliability and reproducibility of 3D-CBCT (cone beam computed tomography) cephalometric landmark identification. Methods : Electronic databases (Pubmed, Scopus, Web of Science) were searched for papers published from 1998 to October 2014. Specifi [...] c strategies were developed for each database, with the guidance of a librarian. Two reviewers independently analyzed the titles and abstracts for inclusion. The articles that met the inclusion and exclusion criteria were selected for full-text reading, and the selected articles went through methodological quality evaluation. After the exclusion of repeated articles, the titles of the remaining ones were read and 1,328 of them were excluded. The abstracts of 173 articles were read, of which 43 were selected, read in full and submitted to the inclusion and exclusion criteria. Fourteen articles or studies with reliable methodology and reproducibility remained. The data were collected, organized into figures and analyzed for determination of the reliability and reproducibility of the three-dimensional cephalometric landmarks. Results : Overall, the landmarks on the median sagittal line and dental landmarks had the highest reliability, while the landmarks on the condyle, porion and the orbitale presented lower levels of reliability. Point S must be marked in the multiplanar views associated with visualization in 3D reconstruction. Further studies are necessary for evaluating soft tissue landmarks.

  12. Anatomical correlations of the international 10-20 sensor placement system in infants.

    Science.gov (United States)

    Kabdebon, C; Leroy, F; Simmonet, H; Perrot, M; Dubois, J; Dehaene-Lambertz, G

    2014-10-01

    Developmental research, as well as paediatric clinical activity crucially depends on non-invasive and painless brain recording techniques, such as electroencephalography (EEG), and near infrared spectroscopy (NIRS). However, both of these techniques measure cortical activity from the scalp without precise knowledge of the recorded cerebral structures. An accurate and reliable mapping between external anatomical landmarks and internal cerebral structures is therefore fundamental to localise brain sources in a non-invasive way. Here, using MRI, we examined the relations between the 10-20 sensor placement system and cerebral structures in 16 infants (3-17 weeks post-term). We provided an infant template parcelled in 94 regions on which we reported the variability of sensors locations, concurrently with the anatomical variability of six main cortical sulci (superior and inferior frontal sulcus, central sulcus, sylvian fissure, superior temporal sulcus, and intraparietal sulcus) and of the distances between the sensors and important cortical landmarks across these infants. The main difference between infants and adults was observed for the channels O1-O2, T5-T6, which projected over lower structures than in adults. We did not find any asymmetry in the distances between the scalp and the brain envelope. However, because of the Yakovlean torque pushing dorsally and frontally the right sylvian fissure, P3-P4 were not at the same distance from the posterior end of this structure. This study should help to refine hypotheses on functional cognitive development by providing an accurate description of the localization of standardised channels relative to infants' brain structures. Template and atlas are publicly available on our Web site (http://www.unicog.org/pm/pmwiki.php/Site/InfantTemplate). PMID:24862070

  13. An anatomical and functional topography of human auditory cortical areas

    Directory of Open Access Journals (Sweden)

    EliaFormisano

    2014-07-01

    Full Text Available While advances in magnetic resonance imaging (MRI throughout the last decades have enabled the detailed anatomical and functional inspection of the human brain non-invasively, to date there is no consensus regarding the precise subdivision and topography of the areas forming the human auditory cortex. Here, we propose a topography of the human auditory areas based on insights on the anatomical and functional properties of human auditory areas as revealed by studies of cyto- and myelo-architecture and fMRI investigations at ultra-high magnetic field (7 Tesla. Importantly, we illustrate that - whereas a group-based approach to analyze functional (tonotopic maps is appropriate to highlight the main tonotopic axis - the examination of tonotopic maps at single subject level is required to detail the topography of primary and non-primary areas that may be more variable across subjects. Furthermore, we show that considering multiple maps indicative of anatomical (i.e. myelination as well as of functional properties (e.g. broadness of frequency tuning is helpful in identifying auditory cortical areas in individual human brains. We propose and discuss a topography of areas that is consistent with old and recent anatomical post mortem characterizations of the human auditory cortex and that may serve as a working model for neuroscience studies of auditory functions.

  14. Femoral arterial puncture: comparison of using the inguinal crease and bony landmarks

    International Nuclear Information System (INIS)

    We tried to compare the accuracy of using bony landmarks and inguinal crease landmarks for performing femoral artery puncture and to determine an ideal puncture site. We studied ninety consecutive patients who underwent femoral arterial puncture for performing angiogram. For the evaluation of bony landmarks, the pelvis and inguinal areas were divided into 8 zones according to 7 lines that were drawn parallel to the line drawn between the anterior superior iliac spine and the pubic tubercle. For evaluation of the inguinal crease as a landmark, the 8 zones above and 4 zones below the inguinal crease were determined. The zones were divided by 11 lines drawn parallel to the inguinal crease, and the interval between each line was 1 cm. Locations of the inguinal ligament and femoral bifurcation were recorded for every patient according to the above zones, and an ideal zone for the femoral arterial puncture was decided upon. The ideal zone was considered if the locations of all of inguinal ligaments were above the zone and the least possibility to puncture was below the femoral bifurcation. On the bony landmark, the femoral bifurcations were located at zone 3 in 1 patient (1.1%), at zone 4 in 2 patients (2.2%), at zone 5 in 3 patients (3.3%), at zone 6 in 24 patients (26.7%), and at zone 7 in 44 patients (48.9%). Inguinal ligaments were at zone 1 in 2 patient (3.0%), at zone 2 in 34 patients (50.7%), at zone 3 in 25 patients (37.3%), and at zone 4 in 6 patients (8.9%). When the inguinal creases were used as a landmark, the femoral bifurcations were located at zone 4 in 4 patients (4.4%), at zone 3 in 19 patients (21.1%). at zone 2 in 30 patients (33.3%), at zone 1 in 19 patients (21.1%), at zone -1 in 13 patients (14.4%), at zone -2 in 3 patients (3.3%) and at zone -4 in 2 patients (2.2%). Inguinal ligaments were at zone 8 in 7 patients (10.4%), at zone 7 in 11 patients (16.4%), at zone 6 in 19 patients (28.4%), at zone 5 in 20 patients (29.9%), at zone 4 in 7 patients (10.4%), and at zone 3 in 3 patients (4.5%). Therefore, the best zone for femoral arterial puncture was zone 5 with using bony landmarks and zone 2 with using inguinal crease landmarks. In terms of zone 5 on the bony landmark, every locations of inguinal ligaments was above it and 84 patients (93.4%) had their femoral bifurcation below it, excluding the 6 patients who had their femoral bifurcations at zones 3, 4, and 5. Therefore, zone 5 with using the bony landmarks was a good indicator for femoral arterial puncture. In case of zone 2 on the inguinal crease landmark, although every location of the inguinal ligament was above it, 53 patients (58.8%) had their femoral bifurcation above it at zone 4, 3, and 2. So, it was not a good indicator for femoral arterial puncture. Bony landmarks are more accurate indicators for performing femoral arterial puncture than the inguinal crease landmark. Zone 5 on the bony landmark is an ideal location for femoral arterial puncture

  15. Personal Landmarks from the Legacy of Arthur Phelps

    Science.gov (United States)

    Lowke, John

    2013-09-01

    I have been influenced for my whole life by Art Phelps, more than by anyone else - other than my wife! I first heard of Art Phelps in 1960 when, in the middle of doing my PhD in Adelaide, South Australia, Frost and Phelps published their land-mark paper, not only on drift velocities, the subject of my PhD, but on Boltzmann analyses, which were to deliver detailed cross sections for all common gases. Later I dared to suggest to my university that one of my two external PhD examiners be Phelps, a move that led to me being accepted for a position at Westinghouse Research Laboratories in Pittsburgh for 6 years, with Phelps as my direct supervisor. Throughout this period, Phelps refused to be a co-author of any of my papers, leaving me with severe doubts as to what he thought of their quality! I list areas where insights from Phelps inspired the growth of new fruit. (1) That transverse and longitudinal electron diffusion coefficients differ, typically by a factor of two. (2) That averaging radiation absorption coefficients in electric arcs, using common weightings involving Black Body radiation, can and usually do lead to errors of orders of magnitude. (3) That CO2 laser discharges are largely controlled by electron attachment rather than by diffusion or recombination. (4) That boundary conditions for electrons at metal electrodes in arc welding, are not zero, but from an astrophysical analogy, are zero when extrapolated to one mean free path beyond the surface. (5) That the metastable vibrational states of nitrogen become an energy gain rather than a loss process for low energy electrons as occur in electrical breakdown in air, resulting in increases of the ionisation coefficient by orders of magnitude. Coupled with the detachment of electrons from negative ions by singlet delta states of metastable oxygen molecules, sustaining discharge electric fields are reduced a factor of five. Phelps worked on this problem with me until a few months before he died.

  16. Comparison of technical and anatomical noise in digital thorax X-ray images

    International Nuclear Information System (INIS)

    Former studies by Hoeschen and Buhr indicated a higher total noise in a thorax image than expected from technical noise, i.e. quantum and detector noise. This difference results from the overlay of many small anatomical structures along the X-ray beam, which leads to a noise-like appearance without distinguishable structures in the projected image. A method is proposed to quantitatively determine this 'anatomical noise' component, which is not to be confused with the anatomical background (e.g. ribs). This specific anatomical noise pattern in a radiograph changes completely when the imaging geometry changes because different small anatomical structures contribute to the projected image. Therefore, two images are taken using slightly different exposure geometry, and a correlation analysis based on wavelet transforms allows to determining the uncorrelated noise components. Since the technical noise also differs from image to image, which makes it difficult to separate the anatomical noise, images of a lung phantom were produced on a low-sensitive industrial X-ray film using high-exposure levels. From these results, the anatomical noise level in real clinical thorax radiographs using realistic exposure levels is predicted using the general dose dependence described in the paper text and compared with the quantum and detector noise level of an indirect flat-panel detector system. For consistency testing, the same lung phantom was imaged with the same digital flat-panel detector and the total image noise including anatomical noise is determined. The results show that the relative portion of anatomical noise may exceed the technical noise level. Anatomical noise is an important contributor to the total image noise and, therefore, impedes the recognition of anatomical structures. (authors)

  17. Pattern recognition of anatomical shapes in CT scans

    International Nuclear Information System (INIS)

    In medical image processing pattern recognition has become of major value in anatomical analysis and in computer aided information processing. Specifically, pattern recognition techniques simplify software development by means of which clinicians can manipulate anatomical relationships. As part of an overall CT pattern recognition system, a sequential edge tracking routine was devised together with a normalized Fourier descriptor analysis of identified shapes. A collection of shapes were extracted from CT scans of two patients and entered into an anatomic shape dictionary. This dictionary was employed in pattern matching experiments and in three-dimensional anatomical reconstruction. A sequential-edge tracking algorithm of high reliability, consistency, and image invariance, capable of utilizing heuristic and statistical rules, was demonstrated. Tests of pattern matching algorithms based on Fourier descriptors provided rapid and accurate body organ recognition of shapes extracted from de novo images using the shape dictionary. Results indicate that automated contour extraction and object recognition from cross-sectional images of human anatomy can be performed effectively, reliably, and rapidly. This abstract discusses an image processing environment that circumvents manual and subjective shape extraction, by substituting automatic and quantitative shape extraction, pattern matching and object recognition

  18. Ethmomaxillary sinus: a particular anatomic variation of the paranasal sinuses

    Energy Technology Data Exchange (ETDEWEB)

    Sirikci, Akif; Bayram, Metin [Department of Radiology, Faculty of Medicine, Gaziantep University, Kolejtepe, 27310, Gaziantep (Turkey); Bayazit, Y.A.; Kanlikama, Muzaffer [Department of Otorhinolaryngology and Head and Neck Surgery, Faculty of Medicine, Gaziantep University, Kolejtepe, 27310, Gaziantep (Turkey)

    2004-02-01

    We assessed the morphological and radiological characteristics of ethmomaxillary sinus (EMS), which is an enlarged posterior ethmoidal air cell occupying the superior portion of the maxillary sinus while draining into superior meatus. This study is based on 1450 patients submitted to CT examination of the paranasal sinuses between 1998 and 2002. Sequential CT scans were obtained in the coronal plane in all the patients with 2.5- to 5-mm section thickness and were evaluated for EMS. The diagnosis of EMS was made when there was a posterior ethmoidal cell occupying the superior part of the maxillary sinus while draining to the superior meatus. When EMS was diagnosed, the morphology of the septum between the and maxillary sinus, and width of the superior meatus, were noted. The EMS was found in 10 of 1450 (0.7%) patients. The coexisting anatomic variations were concha bullosa (50%), upper concha pneumatization (20%), maxillary sinus hypoplasia (20%), uncinate bulla (10%), hypertrophied inferior concha (10%), paradoxic middle concha (10%), and septate maxillary sinus (10%). There was no relation between EMS and sinus disease. The EMS is a rare anatomic variation and does not appear to be associated with sinusitis. The EMS is not a well-studied anatomic variation, and the literature is lacking adequate information about this anatomic variation. This study performed in a large series of patients will possibly contribute to better understanding of this particular anomaly. (orig.)

  19. Visual motion-sensitive neurons in the bumblebee brain convey information about landmarks during a navigational task

    OpenAIRE

    Mertes, Marcel; Dittmar, Laura; Egelhaaf, Martin; Boeddeker, Norbert

    2014-01-01

    Bees use visual memories to find the spatial location of previously learnt food sites. Characteristic learning flights help acquiring these memories at newly discovered foraging locations where landmarks—salient objects in the vicinity of the goal location—can play an important role in guiding the animal's homing behavior. Although behavioral experiments have shown that bees can use a variety of visual cues to distinguish objects as landmarks, the question of how