WorldWideScience
1

Determination of equine deep digital flexor muscle volume based on distances between anatomical landmarks.  

Science.gov (United States)

In equine medicine the use of Botox® is experimental. Dosages are determined from human treatment-protocols and limited numbers of equine studies. Determination of target-muscle volume can be helpful to extrapolate human dosages. The aim of the study was to calculate a formula enabling the estimation of the deep digital flexor muscle (DDFM) volume based on distances between anatomical landmarks. Nineteen cadaveric limbs were collected and distance A (top of olecranon to Os carpi accessorium) and B (circumference of limb) were measured. Converting mathematical formulas, C was calculated: ? × (((0.5B)/?)(2)) × A. DDFM volume was determined by water displacement. Linear Regression Analysis was used to analyse data. The line best fitting the observed points was: Ln(volume[ml])?=?-1.89 + 0.98 × Ln(value C[cm(3)]). Correlation was highest when natural logarithm was applied to both variables and was 0.97. The calculated formula enables estimating DDFM volume of a living horse. This estimated volume can be useful to apply human Botox® treatment-protocols. PMID:25264361

Hardeman, L C; van der Meij, B R; Lamers, A A H; van der Kolk, J H; Back, W; Wijnberg, I D

2014-10-01

2

Validation and detection of vessel landmarks by using anatomical knowledge  

Science.gov (United States)

The detection of anatomical landmarks is an important prerequisite to analyze medical images fully automatically. Several machine learning approaches have been proposed to parse 3D CT datasets and to determine the location of landmarks with associated uncertainty. However, it is a challenging task to incorporate high-level anatomical knowledge to improve these classification results. We propose a new approach to validate candidates for vessel bifurcation landmarks which is also applied to systematically search missed and to validate ambiguous landmarks. A knowledge base is trained providing human-readable geometric information of the vascular system, mainly vessel lengths, radii and curvature information, for validation of landmarks and to guide the search process. To analyze the bifurcation area surrounding a vessel landmark of interest, a new approach is proposed which is based on Fast Marching and incorporates anatomical information from the knowledge base. Using the proposed algorithms, an anatomical knowledge base has been generated based on 90 manually annotated CT images containing different parts of the body. To evaluate the landmark validation a set of 50 carotid datasets has been tested in combination with a state of the art landmark detector with excellent results. Beside the carotid bifurcation the algorithm is designed to handle a wide range of vascular landmarks, e.g. celiac, superior mesenteric, renal, aortic, iliac and femoral bifurcation.

Beck, Thomas; Bernhardt, Dominik; Biermann, Christina; Dillmann, Rüdiger

2010-03-01

3

Anatomic Landmarks for the First Dorsal Compartment  

OpenAIRE

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 ...

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

2009-01-01

4

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

Energy Technology Data Exchange (ETDEWEB)

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.)

Manzke, R.; Shechter, G.; Gutierrez, L.; Chan, R.C. [Philips Research North America, Briarcliff Manor, NY (United States); Tournoux, F.; Singh, J.; Picard, M. [Dept. of Cardiology, Massachusetts General Hospital, Harvard Medical School (United States); Brink, B. v.d.; Boomen, R. v.d. [Philips Medical System, Best (Netherlands); Gerard, O. [Philips Medical Systems, Paris (France)

2007-06-15

5

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.)

6

Cardiac Conduction System: Delineation of Anatomic Landmarks With Multidetector CT  

Directory of Open Access Journals (Sweden)

Full Text Available 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 landmarks include the right SAN artery, right atrial cavotricuspid isthmus, Koch triangle, AVN artery, interatrial muscle bundles, and pulmonary veins. In addition, MDCT has an imperative role in demarcating potential arrhythmogenic structures. The aim of this review will be to assess the extent at which MDCT can outline the described anatomic landmarks and therefore provide crucial information used in clinical practice.

Farhood Saremi

2009-11-01

7

Intra-Articular Hip Injection Using Anatomic Surface Landmarks  

OpenAIRE

Intra-articular hip injection is a frequently used technique for diagnostic and therapeutic purposes and is gaining more importance for the early diagnosis of hip disease. It is commonly performed with imaging guidance such as ultrasonographic or fluoroscopic control. We describe our technique of injection of the hip using relative distances from anatomic surface landmarks, with the needle insertion point at the site of the proximal anterolateral portal for hip arthroscopy, with a posterior d...

Masoud, Mohammad A.; Said, Hatem G.

2013-01-01

8

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)

9

The use of anatomical landmarks for percutaneous nephrolithotomy  

Directory of Open Access Journals (Sweden)

Full Text Available Objective: The aim of our study was to describe the external anatomical landmarks and angles as a training guide for urologists in the performance of percutaneous nephrolithotomy (PCNL in the prone position. Materials and Methods: Between 2006 and 2008, 50 patients (including 10 resident cases undergoing PCNL met the study criteria. The inclusion criteria consisted of patients with renal stones scheduled for a lower calyceal puncture PCNL where the number of attempts to access the calyx ? 3, and clear urine was seen draining from the needle. The exclusion criteria consisted of previous ipsilateral kidney surgery, severe hydronephrosis, anomalies of the renal or skeletal systems, BMI>30 kg/m2, upper/middle calyceal puncture and age ?18. Several anatomical landmarks and angles were measured, recorded and analyzed. Results: The mean length of (Pi was 10.1±1.7 cm (range 7-14, (Pe was 9.9±1.7 cm (range 6-13, (a was 11.2±2.8 cm (range 5.5-17, (b was 5.3±2.3 cm (range 1.5-11 cm, (x was 5.1±1.9 cm (range 1-8, (x1 was 3.3±1.7 cm (range 1.5-8.2, (y was 7.1±1.7 cm (range 3.3-11.6, (y1 was 3.8±1.6 cm (range 1-9 and (t was 4.9±1.7 cm (range 3-9. The mean angle for (a was 49±13º (range 30-70º, (b was 41±13º (range 20-70º and (g was 61±13º (range 28-80º. In resident cases, the median number of attempts was 1 (range 1-3, the median overall time for successful access was 7.25 minutes (range 2-12 and the median fl uoroscopy time was 62.5 seconds (range 30-150. Conclusion: A knowledge of these anatomical landmarks and angles may increase the capacity of urologists to repetitively perform the precise task of percutaneous access of the lower calyceal during PCNL.

Esat Kaan Akbay

2012-06-01

10

Intra-articular hip injection using anatomic surface landmarks.  

Science.gov (United States)

Intra-articular hip injection is a frequently used technique for diagnostic and therapeutic purposes and is gaining more importance for the early diagnosis of hip disease. It is commonly performed with imaging guidance such as ultrasonographic or fluoroscopic control. We describe our technique of injection of the hip using relative distances from anatomic surface landmarks, with the needle insertion point at the site of the proximal anterolateral portal for hip arthroscopy, with a posterior direction of 30° and targeted toward a junctional point between 2 perpendicular lines, 1 distal from the anterior superior iliac spine and the second anterior from the tip of the greater trochanter. This technique can be used without imaging guidance in the outpatient clinic. Moreover, it minimizes the need for radiographic exposure for more critical injections, such as the injection of contrast material before conducting magnetic resonance arthrogaphy of the hip. PMID:23875141

Masoud, Mohammad A; Said, Hatem G

2013-05-01

11

Technical note: Quantification of neurocranial shape variation using the shortest paths connecting pairs of anatomical landmarks.  

Science.gov (United States)

Three-dimensional geometric morphometric techniques have been widely used in quantitative comparisons of craniofacial morphology in humans and nonhuman primates. However, few anatomical landmarks can actually be defined on the neurocranium. In this study, an alternative method is proposed for defining semi-landmarks on neurocranial surfaces for use in detailed analysis of cranial shape. Specifically, midsagittal, nuchal, and temporal lines were approximated using Bezier curves and equally spaced points along each of the curves were defined as semi-landmarks. The shortest paths connecting pairs of anatomical landmarks as well as semi-landmarks were then calculated in order to represent the surface morphology between landmarks using equally spaced points along the paths. To evaluate the efficacy of this method, the previously outlined technique was used in morphological analysis of sexual dimorphism in modern Japanese crania. The study sample comprised 22 specimens that were used to generate 110 anatomical semi-landmarks, which were used in geometric morphometric analysis. Although variations due to sexual dimorphism in human crania are very small, differences could be identified using the proposed landmark placement, which demonstrated the efficacy of the proposed method. PMID:23868177

Morita, Yusuke; Ogihara, Naomichi; Kanai, Takashi; Suzuki, Hiromasa

2013-08-01

12

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

Science.gov (United States)

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 of the sphenoid sinus and relevant arteries and the morphological characteristics of the anterior wall of the sphenoid sinus and sellar floor were observed and recorded. The important anatomical landmarks included the mucosal aperture of the sphenoid sinus, a blunt longitudinal prominence on the posterior nasal septum, the osseocartilaginous junction of the nasal septum, the ‘bow sign’ of the anterior wall of the sphenoid sinus, the osseous aperture and its relationship with the nutrient arteries, the bulge of the sellar floor and the carotid protuberance. These landmarks outlined a clear route to the sella turcica with an optimal view and lesser tissue damage. Although morphological variation may exist, the position of these landmarks was generally consistent. Locating the sphenoid sinus aperture is the gold standard to direct the surgical route of TSS. The ‘bow sign’ and the sellar bulge are critical landmarks for accurate entry into the sphenoid sinus and sella fossa, respectively. PMID:23596471

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

2013-01-01

13

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

Science.gov (United States)

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 of the sphenoid sinus and relevant arteries and the morphological characteristics of the anterior wall of the sphenoid sinus and sellar floor were observed and recorded. The important anatomical landmarks included the mucosal aperture of the sphenoid sinus, a blunt longitudinal prominence on the posterior nasal septum, the osseocartilaginous junction of the nasal septum, the 'bow sign' of the anterior wall of the sphenoid sinus, the osseous aperture and its relationship with the nutrient arteries, the bulge of the sellar floor and the carotid protuberance. These landmarks outlined a clear route to the sella turcica with an optimal view and lesser tissue damage. Although morphological variation may exist, the position of these landmarks was generally consistent. Locating the sphenoid sinus aperture is the gold standard to direct the surgical route of TSS. The 'bow sign' and the sellar bulge are critical landmarks for accurate entry into the sphenoid sinus and sella fossa, respectively. PMID:23596471

Wei, Liang-Feng; Zhang, Jinchao; Chen, Hong-Jie; Wang, Rumi

2013-04-01

14

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 d to be reproducible in 15 bony landmarks on the skull. (N.K.)

15

Autonomous Robot Navigation based on Visual Landmarks  

DEFF Research Database (Denmark)

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.

Livatino, Salvatore

16

The Cystic Vein: The Significance of a Forgotten Anatomic Landmark  

OpenAIRE

The cystic vein, a portion of biliary anatomy whose insignificance in open gallbladder surgery led to its being relegated to mythology, has been rediscovered by the magnified view of laparoscopic surgery. Its presence is an important anatomic feature that helps distinguish between cystic duct and common hepatic duct, thus diminishing the risk of inadvertent bile duct injury during laparoscopic cholecystectomy.

Arthur, Fine

1997-01-01

17

The stylomastoid artery as an anatomical landmark to the facial nerve during parotid surgery: a clinico-anatomic study  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background The identification of the facial nerve can be difficult in a bloody operative field or by an incision that limits exposure; hence anatomical landmarks and adequate operative exposure can aid such identification and preservation. In this clinico-anatomic study, we examined the stylomastoid artery (SMA and its relation to the facial nerve trunk; the origin of the artery was identified on cadavers and its nature was confirmed histologically. Methods The clinical component of the study included prospective reviewing of 100 consecutive routine parotidectomies; while, the anatomical component of the study involved dissecting 50 cadaveric hemifaces. Results We could consistently identify a supplying vessel, stylomastoid artery, which tends to vary less in position than the facial nerve. Following this vessel, a few millimetres inferiorly and medially, we have gone on to identify the facial nerve trunk, which it supplies, with relative ease. The origin of the stylomastoid artery, in our study, was either from the occipital artery or the posterior auricular artery. Conclusion This anatomical aid, the stylomastoid artery, when supplemented by the other more commonly known anatomical landmarks and intra-operative facial nerve monitoring further reduces the risk of iatrogenic facial nerve damage and operative time.

Nouraei Seyed

2009-09-01

18

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 beforrebrain 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.)

19

Reliability of Bony Anatomic Landmark Asymmetry Assessment in the Lumbopelvic Region: Application to Osteopathic Medical Education  

OpenAIRE

The objective of this review is to establish the current state of knowledge on the reliability of clinical assessment of asymmetry in the lumbar spine and pelvis. To search the literature, the authors consulted the databases of MEDLINE, CINAHL, AMED, MANTIS, Academic Search Complete, and Web of Knowledge using different combinations of the following keywords: palpation, asymmetry, inter- or intraex-aminer reliability, tissue texture, assessment, and anatomic landmark. Of the 23 studies identi...

Stovall, Bradley A.; Kumar, Shrawan

2010-01-01

20

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

Energy Technology Data Exchange (ETDEWEB)

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.)

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

21

A multi-subject evaluation of uncertainty in anatomical landmark location on shoulder kinematic description.  

Science.gov (United States)

An accurate assessment of shoulder kinematics is useful for understanding healthy normal and pathological mechanics. Small variability in identifying and locating anatomical landmarks (ALs) has potential to affect reported shoulder kinematics. The objectives of this study were to quantify the effect of landmark location variability on scapular and humeral kinematic descriptions for multiple subjects using probabilistic analysis methods, and to evaluate the consistency in results across multiple subjects. Data from 11 healthy subjects performing humeral elevation in the scapular plane were used to calculate Euler angles describing humeral and scapular kinematics. Probabilistic analyses were performed for each subject to simulate uncertainty in the locations of 13 upper-extremity ALs. For standard deviations of 4 mm in landmark location, the analysis predicted Euler angle envelopes between the 1 and 99 percentile bounds of up to 16.6 degrees . While absolute kinematics varied with the subject, the average 1-99% kinematic ranges for the motion were consistent across subjects and sensitivity factors showed no statistically significant differences between subjects. The description of humeral kinematics was most sensitive to the location of landmarks on the thorax, while landmarks on the scapula had the greatest effect on the description of scapular elevation. The findings of this study can provide a better understanding of kinematic variability, which can aid in making accurate clinical diagnoses and refining kinematic measurement techniques. PMID:19021031

Langenderfer, Joseph E; Rullkoetter, Paul J; Mell, Amy G; Laz, Peter J

2009-04-01

22

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

Science.gov (United States)

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.

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

2012-05-01

23

Geometric sensitivity of patient-specific finite element models of the spine to variability in user-selected anatomical landmarks.  

Science.gov (United States)

Software to create individualised finite element (FE) models of the osseoligamentous spine using pre-operative computed tomography (CT) data-sets for spinal surgery patients has recently been developed. This study presents a geometric sensitivity analysis of this software to assess the effect of intra-observer variability in user-selected anatomical landmarks. User-selected landmarks on the osseous anatomy were defined from CT data-sets for three scoliosis patients and these landmarks were used to reconstruct patient-specific anatomy of the spine and ribcage using parametric descriptions. The intra-observer errors in landmark co-ordinates for these anatomical landmarks were calculated. FE models of the spine and ribcage were created using the reconstructed anatomy for each patient and these models were analysed for a loadcase simulating clinical flexibility assessment. The intra-observer error in the anatomical measurements was low in comparison to the initial dimensions, with the exception of the angular measurements for disc wedge and zygapophyseal joint (z-joint) orientation and disc height. This variability suggested that CT resolution may influence such angular measurements, particularly for small anatomical features, such as the z-joints, and may also affect disc height. The results of the FE analysis showed low variation in the model predictions for spinal curvature with the mean intra-observer variability substantially less than the accepted error in clinical measurement. These findings demonstrate that intra-observer variability in landmark point selection has minimal effect on the subsequent FE predictions for a clinical loadcase. PMID:24261987

Little, J P; Adam, C J

2015-01-01

24

Arterial tree tracking from anatomical landmarks in magnetic resonance angiography scans  

Science.gov (United States)

This paper reports on arterial tree tracking in fourteen Contrast Enhanced MRA volumetric scans, given the positions of a predefined set of vascular landmarks, by using the A* algorithm to find the optimal path for each vessel based on voxel intensity and a learnt vascular probability atlas. The algorithm is intended for use in conjunction with an automatic landmark detection step, to enable fully automatic arterial tree tracking. The scan is filtered to give two further images using the top-hat transform with 4mm and 8mm cubic structuring elements. Vessels are then tracked independently on the scan in which the vessel of interest is best enhanced, as determined from knowledge of typical vessel diameter and surrounding structures. A vascular probability atlas modelling expected vessel location and orientation is constructed by non-rigidly registering the training scans to the test scan using a 3D thin plate spline to match landmark correspondences, and employing kernel density estimation with the ground truth center line points to form a probability density distribution. Threshold estimation by histogram analysis is used to segment background from vessel intensities. The A* algorithm is run using a linear cost function constructed from the threshold and the vascular atlas prior. Tracking results are presented for all major arteries excluding those in the upper limbs. An improvement was observed when tracking was informed by contextual information, with particular benefit for peripheral vessels.

O'Neil, Alison; Beveridge, Erin; Houston, Graeme; McCormick, Lynne; Poole, Ian

2014-03-01

25

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

Energy Technology Data Exchange (ETDEWEB)

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

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

26

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 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

27

Neural systems for landmark-based wayfinding in humans.  

Science.gov (United States)

Humans and animals use landmarks during wayfinding to determine where they are in the world and to guide their way to their destination. To implement this strategy, known as landmark-based piloting, a navigator must be able to: (i) identify individual landmarks, (ii) use these landmarks to determine their current position and heading, (iii) access long-term knowledge about the spatial relationships between locations and (iv) use this knowledge to plan a route to their navigational goal. Here, we review neuroimaging, neuropsychological and neurophysiological data that link the first three of these abilities to specific neural systems in the human brain. This evidence suggests that the parahippocampal place area is critical for landmark recognition, the retrosplenial/medial parietal region is centrally involved in localization and orientation, and both medial temporal lobe and retrosplenial/medial parietal lobe regions support long-term spatial knowledge. PMID:24366141

Epstein, Russell A; Vass, Lindsay K

2014-02-01

28

Automatic Evaluation of Landmarks for Image-Based Navigation Update  

Directory of Open Access Journals (Sweden)

Full Text Available The successful mission of an autonomous airborne system like an unmanned aerial vehicle (UAV strongly depends on its accurate navigation. While GPS is not always available and pose estimation based solely on Inertial Measurement Unit (IMU drifts, image-based navigation may become a cheap and robust additional pose measurement device. For the actual navigation update a landmark-based approach is used. It is essential that the used landmarks are well chosen. Therefore we introduce an approach for evaluating landmarks in terms of the matching distance, which is the maximum misplacement in the position of the landmark that can be corrected. We validate the evaluations with our 3D reconstruction system working on data captured from a helicopter.

Stefan Lang

2009-01-01

29

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 dcer. 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

30

Adaptive Landmark-Based Navigation System Using Learning Techniques  

DEFF Research Database (Denmark)

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.

Zeidan, Bassel; Dasgupta, Sakyasingha

2014-01-01

31

Does spatial locative comprehension predict landmark-based navigation?  

Science.gov (United States)

In the present study we investigated the role of spatial locative comprehension in learning and retrieving pathways when landmarks were available and when they were absent in a sample of typically developing 6- to 11-year-old children. Our results show that the more proficient children are in understanding spatial locatives the more they are able to learn pathways, retrieve them after a delay and represent them on a map when landmarks are present in the environment. These findings suggest that spatial language is crucial when individuals rely on sequences of landmarks to drive their navigation towards a given goal but that it is not involved when navigational representations based on the geometrical shape of the environment or the coding of body movements are sufficient for memorizing and recalling short pathways. PMID:25629814

Piccardi, Laura; Palermo, Liana; Bocchi, Alessia; Guariglia, Cecilia; D'Amico, Simonetta

2015-01-01

32

Combining Speedup techniques based on Landmarks and Containers  

Directory of Open Access Journals (Sweden)

Full Text Available The Dijkstra’s algorithm [1] , which is applied in many real world problems like mobile routing, road maps, railway networks, etc,. is used to find the shortest path between source and destination. There are many techniques available to speedup the algorithm while guaranteeing the optimality of the solution. The main focus of the work is to implement landmark technique and Containers separately and compare the results with random graphs and planar graphs. The combined speedup technique which is based on landmarks and containers were also experimented with random graphs and planar graphs to improvethe speedup of the shortest path queries.

R. KALPANA

2010-09-01

33

Role of squamosal suture as a consistent landmark for middle fossa approach craniotomy: an anatomical study.  

Science.gov (United States)

Objective?To establish a consistent surface bony landmark for a middle fossa approach (MFA) lateral craniotomy represented by the squamosal suture (SS). Methods?In 60 dried skulls, we assessed the relation between the SS and the external auditory canal (EAC). The lateral portion of the middle cranial fossa floor was also assessed for a possible relation with the anteroposterior diameter (APD) of the squama temporalis (ST). Clinically, we applied our findings on the SS in MFA for different lesions. Results?A vertical line at the EAC divided the ST into the anterior part constituting 61% of the APD (i.e., two thirds) and the posterior part forming 39% (i.e., one third). The average ST height was 35.92 mm. The SS posterior limit at the supramastoid crest was located just anterior to the external projection of the petrous ridge in 35 skulls (58%) and exactly corresponded to it in 25 skulls (42%). The APD of the ST equals on average 97% of the APD of the lateral middle cranial fossa. Optimum exposure of the middle fossa was obtained without any further craniotomy extension. Conclusion?The SS serves as a consistent natural surface bony landmark for MFA. Optimum craniotomy, two thirds anterior to the EAC and one third posterior, is obtained following SS as a landmark. PMID:25685647

Alkhalili, Kenan; Tantawy, Mohammed; Nageeb, Mohab M; Ragaee, Mohamed A; Alshyal, Gasser H; Alcindor, Dunbar S; Chen, Douglas A; Aziz, Khaled M Abdel

2015-02-01

34

Dynamic magnetic resonance imaging: reliability of anatomical landmarks and reference lines used to assess pelvic organ prolapse.  

Science.gov (United States)

The aim of this study was to determine the intra- and interobserver reliability of dynamic magnetic resonance (MR) staging in pelvic organ prolapse patients. In 30 patients with pelvic organ prolapse, dynamic MR images were assessed independently by two observers. Various anatomical landmarks to asses pelvic organ prolapse were used in relation to the pubococcygeal line, H-line, and mid-pubic line. Clinical measurement points were assessed in relation to the mid-pubic line. The intraclass correlation coefficients (ICC) were calculated to describe the intra- and interobserver reliability. Overall, the intra- and interobserver reliability of MR imaging measurements was excellent to good. The pubococcygeal line showed superior reliability (ICC range 0.70-0.99). The reliability of clinical measurement points, however, were only moderate (ICC range 0.20-0.96). The intra- and interobserver reliability of quantitative prolapse staging on dynamic MR imaging were good to excellent. The pubococcygeal line appears the most reliable to use. PMID:19002366

Broekhuis, Suzan R; Kluivers, Kirsten B; Hendriks, Jan C M; Vierhout, Mark E; Barentsz, Jelle O; Fütterer, Jurgen J

2009-02-01

35

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

Directory of Open Access Journals (Sweden)

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.

udy P. Sendaydiego

2013-07-01

36

Robust Discriminative Tracking via Landmark-Based Label Propagation.  

Science.gov (United States)

The appearance of an object could be continuously changing during tracking, thereby being not independent identically distributed. A good discriminative tracker often needs a large number of training samples to fit the underlying data distribution, which is impractical for visual tracking. In this paper, we present a new discriminative tracker via landmark-based label propagation (LLP) that is nonparametric and makes no specific assumption about the sample distribution. With an undirected graph representation of samples, the LLP locally approximates the soft label of each sample by a linear combination of labels on its nearby landmarks. It is able to effectively propagate a limited amount of initial labels to a large amount of unlabeled samples. To this end, we introduce a local landmarks approximation method to compute the cross-similarity matrix between the whole data and landmarks. Moreover, a soft label prediction function incorporating the graph Laplacian regularizer is used to diffuse the known labels to all the unlabeled vertices in the graph, which explicitly considers the local geometrical structure of all samples. Tracking is then carried out within a Bayesian inference framework, where the soft label prediction value is used to construct the observation model. Both qualitative and quantitative evaluations on the benchmark data set containing 51 challenging image sequences demonstrate that the proposed algorithm outperforms the state-of-the-art methods. PMID:25706637

Wu, Yuwei; Pei, Mingtao; Yang, Min; Yuan, Junsong; Jia, Yunde

2015-05-01

37

Vision based landmark detection for UAV navigation  

OpenAIRE

The majority of Unmanned Aerial Vehicles (UAV) available today depend on Global Position Satellites (GPS) and inertial measurement units (IMU) for state estimation used in navigation and control. However with the increase in availability of cheap GPS jamming technologies leads to concerns over the dependence of GPS for control and navigation. A possible solution is to use a downward looking camera on-board the aircraft, and using vision based techniques the aircraft can estimate its position ...

Elliott, Alexander William

2012-01-01

38

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

39

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

Science.gov (United States)

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.

Ghimire, Deepak; Lee, Joonwhoan

2014-01-01

40

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

41

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)

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.

T ahmine Razi

2013-05-01

42

The Landmark-based Meta Best-First Search Algorithm for Classical Planning.  

OpenAIRE

In this paper, we revisit the idea of splitting a planning problem into subproblems hopefully easier to solve with the help of landmark analysis. This technique initially proposed in the first approaches related to landmarks in classical planning has been outperformed by landmark-based heuristics and has not been paid much attention over the last years. We believe that it is still a promising research direction, particularly for devising distributed search algorithms that could explore differ...

Vernhes, S.; Infantes, G.; Vidal, V.

2012-01-01

43

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

OpenAIRE

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, ...

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

2014-01-01

44

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)

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.

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

45

Shape representation for efficient landmark-based segmentation in 3-d.  

Science.gov (United States)

In this paper, we propose a novel approach to landmark-based shape representation that is based on transportation theory, where landmarks are considered as sources and destinations, all possible landmark connections as roads, and established landmark connections as goods transported via these roads. Landmark connections, which are selectively established, are identified through their statistical properties describing the shape of the object of interest, and indicate the least costly roads for transporting goods from sources to destinations. From such a perspective, we introduce three novel shape representations that are combined with an existing landmark detection algorithm based on game theory. To reduce computational complexity, which results from the extension from 2-D to 3-D segmentation, landmark detection is augmented by a concept known in game theory as strategy dominance. The novel shape representations, game-theoretic landmark detection and strategy dominance are combined into a segmentation framework that was evaluated on 3-D computed tomography images of lumbar vertebrae and femoral heads. The best shape representation yielded symmetric surface distance of 0.75 mm and 1.11 mm, and Dice coefficient of 93.6% and 96.2% for lumbar vertebrae and femoral heads, respectively. By applying strategy dominance, the computational costs were further reduced for up to three times. PMID:24710155

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

2014-04-01

46

Reliability of Determination of Bony Landmarks of the Distal Femur on MR Images and MRI-Based 3D Models  

Directory of Open Access Journals (Sweden)

Full Text Available Background/Objective: Consistent determination of the anatomical landmarks on image or image-based three dimensional (3D models is a basic requirement for reliable analysis of the human joint kinematics using imaging techniques. We examined the intra- and inter-observer reliability of determination of the medial and lateral epicondyle landmarks on 2D MR images and 3D MRI-based models of the knee. "n"n Materials and Methods: Sixteen coronal plane MRI recordings were taken from 18 healthy knees using a knee coil with T2-weighted fast spin-echo sequence and 512×512 pixel size. They were then processed by the Mimics software to provide the coronal and axial plane views and to create a 3D image-based model of the femur. Each image was reviewed twice, at least one-day apart. The interclass correlation coefficient, standard error of measurement, and coefficient of variation were calculated to assess the intra- and inter-observer reliability of the landmark determination by six experienced radiologists. A mixed model analysis of variance (ANOVA with two days of observation as the within-subject factor, and observers (six radiologists and methods (2D vs. 3D as between-subject factors were used to test the effect of observer, two days of observation and method of evaluation on landmark determination. Results: The results indicated that the interclass correlation coefficients for the intra-observer and inter-observer determination of landmarks on images and image-based 3D models were above 0.97. The standard error of measurement ranged between 0.41 and 0.78 mm for x; 1.35 and 3.43 mm for y; and 1.03 and 4.71 mm for z coordinates. Furthermore, the results showed no significant difference for within and between-subject comparisons of each coordinate of the lateral epicondyle as well as x and z coordinates of the medial epicondyle. For the y coordinate of the medial epicondyle, the p value of within-subject comparison was borderlinely significant (p=0.049. Conclusion: It was concluded that the intra- and inter-observer reliability of the bony landmark determination on both image and image-based 3D models were excellent.    

F. Esfandiarpour

2009-12-01

47

A class of spline functions for landmark-based image registration  

OpenAIRE

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...

Rossi, Alessandra; Cavoretto, Roberto; Allasia, Giampietro

2011-01-01

48

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)

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

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

2014-10-01

49

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 lea 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

50

Identification of an Alternate Maxillary Apical Base Landmark from Pre-existing Substitutions  

Science.gov (United States)

ABSTRACT Background: Cephalometrically the position of maxilla is usually assessed by point A, which is one of the most common cephalometric landmarks used for spatial analysis of maxilla, however in certain scenarios we require a alternative landmark. Aims: In this study a nearest alternative maxillary apical base landmark was identified for Point A substitutions given by different authors. Methods and Material: A cross sectional study was conducted on thirty (30) good quality lateral cephalograms. Only those lateral cephalograms were selected where Point A was easily identified. Landmarks: Sella (S), Nasion (N), Point A and three substitution points Y, L, X were traced. Angles formed by SN with Point A (Angle SNA) and three substitution points (Angle SNY, SNX, SNL) were measured. Correlation of angle SNA with angles SNY, SNX and SNL were derived. Statistical analysis used Results: Mean and standard deviation for Angles SNA, SNY, SNL and SNX were calculated individually for males and females. ‘T’ Test was applied to determine statistical significance for all the parameters i.e Age, Angles SNA, SNY, SNL and SNX respectively. Karl Pearson correlation coefficient was carried out to determine the statistical significant correlation for Angle SNA with SNY, SNL and SNX. Results: A mean value of 82.8° ±1.9°, 83.1° ±1.8°, 78.3° ±2.9° and 78.7° ±2.7° for Angle's SNA, SNY, SNL and SNX respectively was observed. A statistically significant correlation was observed between angles SNA & SNY, SNL, SNX & strong positive correlation was observed with angle SNY. Conclusions: We conclude that Point Y is the most nearing maxillary apical base landmark to Point A. Hence maxillary apical base landmark can be substituted by Point Y where identification of point A is not obvious. PMID:25568586

Patel, Kunal S.; Kulkarni, Narayan; Singh, Varun Pratap; Parikh, Kartik

2014-01-01

51

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

Directory of Open Access Journals (Sweden)

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.

Nihat Y?lmaz

2006-06-01

52

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

Science.gov (United States)

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

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

2014-12-01

53

Expressive anatomical illustrations based on scanned patient data  

OpenAIRE

The art and profession of medical illustration depend not only on the talent and skills of an illustrator, but also on the complimentary knowledge of human anatomy. Therefore, anatomical illustrations were mostly based on comprehensive dissections and observations during surgery. Recently, illustrative visualization techniques have been utilized to illustrate features and shapes of anatomical objects. Thereby, illustrative visualization provides representations that highlight relevant feature...

Salah, Z.; Bartz, D.; Straßer, W.; Tatagiba, M.

2006-01-01

54

Visual Homing in the Absence of Feature-Based Landmark Information  

Science.gov (United States)

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,…

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

2008-01-01

55

Landmark-based registration using a local radial basis function transformation  

OpenAIRE

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.

Cavoretto, Roberto; Rossi, Alessandra; Quatember, Bernhard

2011-01-01

56

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.)

57

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)

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.)

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

58

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

Science.gov (United States)

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

Wang, Hongsheng; Zheng, Naiqaun Nigel

2010-12-01

59

Common Carotid Artery Bifurcation Levels Related to Clinical Relevant Anatomical Landmarks Niveles de Bifurcación de la Arteria Carótida Común en Relación a Puntos de Referencia Anatómicos Relevantes en Clínica  

Directory of Open Access Journals (Sweden)

Full Text Available In head and neck surgery, the common carotid arteries are important landmarks, defining dissection plane during radical neck surgeries. The objectives of the present study were to add information on the diameter of the carotid arteries and to correlate the common carotid artery (CCA bifurcation level with important anatomical landmarks used regularly in clinical practice. Forty-six necks from male embalmed human cadavers were evaluated. The CCA as the external (ECA and internal (ICA carotid arteries diameters were studied with the aid of an electronic digital caliper. No differences were found between sides in any level studied. The CCA bifurcation level was measured in relation to clinically relevant anatomical landmarks (superior level of the thyroid cartilage, mandible angle and ear lobe and the bifurcation level according to the cervical vertebra level was also investigated. Our study shows that the superior border of the thyroid cartilage was the most stable anatomical landmark for predicting the CCA bifurcation level. It is important to mention that from all the landmarks studied, the cervical vertebra was the only one to show differences between sides, with the left side bifurcation level more variable than the right sideEn cirugías de cabeza y cuello, las arterias carótidas comunes son importantes puntos de referencia, para defnir el plano de disección, durante cirugías radicales de cuello. Los objetivos del presente estudio fueron agregar información sobre el diámetro de las arterias carótidas y correlacionar el nivel de bifurcación de la arteria carótida común (ACC con importantes puntos de referencia usados regularmente en la práctica clínica. Para la obtención de los objetivos planteados, fueron evaluados 46 cadáveres formolizados de individuos de sexo masculino. Se obtuvieron los diámetros de las arterias carótidas común, externa (ACE e interna (ACI, con el auxilio de un caliper digital. No hubo diferencias entre lados derecho e izquierdo, ni tampoco en los niveles estudiados. El nivel de bifurcación de la ACC fue medido en relación a puntos de reparos anatómicos relevantes en clínica (margen superior del cartílago tiroides, ángulo de la mandíbula y lóbulo del pabellón auricular, como también en relación al nivel vertebral. Nuestro estudio mostró que el margen superior del cartílago tiroides fue el punto de referencia más estable para inferir el nivel de bifurcación de la ACC. Es importante mencionar que, de todos los puntos de referencia estudiados, la vértebra cervical fue la única que mostró diferencias entre los lados, siendo más variable el nivel de bifurcación en el lado izquierdo

Rogério Alves Ribeiro

2006-09-01

60

Common Carotid Artery Bifurcation Levels Related to Clinical Relevant Anatomical Landmarks / Niveles de Bifurcación de la Arteria Carótida Común en Relación a Puntos de Referencia Anatómicos Relevantes en Clínica  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in spanish En cirugías de cabeza y cuello, las arterias carótidas comunes son importantes puntos de referencia, para defnir el plano de disección, durante cirugías radicales de cuello. Los objetivos del presente estudio fueron agregar información sobre el diámetro de las arterias carótidas y correlacionar el n [...] ivel de bifurcación de la arteria carótida común (ACC) con importantes puntos de referencia usados regularmente en la práctica clínica. Para la obtención de los objetivos planteados, fueron evaluados 46 cadáveres formolizados de individuos de sexo masculino. Se obtuvieron los diámetros de las arterias carótidas común, externa (ACE) e interna (ACI), con el auxilio de un caliper digital. No hubo diferencias entre lados derecho e izquierdo, ni tampoco en los niveles estudiados. El nivel de bifurcación de la ACC fue medido en relación a puntos de reparos anatómicos relevantes en clínica (margen superior del cartílago tiroides, ángulo de la mandíbula y lóbulo del pabellón auricular), como también en relación al nivel vertebral. Nuestro estudio mostró que el margen superior del cartílago tiroides fue el punto de referencia más estable para inferir el nivel de bifurcación de la ACC. Es importante mencionar que, de todos los puntos de referencia estudiados, la vértebra cervical fue la única que mostró diferencias entre los lados, siendo más variable el nivel de bifurcación en el lado izquierdo Abstract in english In head and neck surgery, the common carotid arteries are important landmarks, defining dissection plane during radical neck surgeries. The objectives of the present study were to add information on the diameter of the carotid arteries and to correlate the common carotid artery (CCA) bifurcation lev [...] el with important anatomical landmarks used regularly in clinical practice. Forty-six necks from male embalmed human cadavers were evaluated. The CCA as the external (ECA) and internal (ICA) carotid arteries diameters were studied with the aid of an electronic digital caliper. No differences were found between sides in any level studied. The CCA bifurcation level was measured in relation to clinically relevant anatomical landmarks (superior level of the thyroid cartilage, mandible angle and ear lobe) and the bifurcation level according to the cervical vertebra level was also investigated. Our study shows that the superior border of the thyroid cartilage was the most stable anatomical landmark for predicting the CCA bifurcation level. It is important to mention that from all the landmarks studied, the cervical vertebra was the only one to show differences between sides, with the left side bifurcation level more variable than the right side

Rogério Alves, Ribeiro; João Alberto de Souza, Ribeiro; Omar Andrade, Rodrigues Filho; Abadio Gonçalves, Caetano; Valéria Paula Sassoli, Fazan.

2006-09-01

61

Combining Speedup Techniques based on Landmarks and Containers with parallelised preprocessing in Random and Planar Graphs  

Directory of Open Access Journals (Sweden)

Full Text Available The Dijkstra’s algorithm is applied in many real world problems like mobile routing, road maps,railway networks, etc,. There are many techniques available to speedup the algorithm while guaranteeingthe optimality of the solution. Almost all of the speedup techniques have a substantial amount of parallelism that can be exploited to decrease its running time. By suitably modifying portions of theexisting system various degrees of parallelism can be achieved. The rapidly growing field of multiprocessing systems and multi-core processors provide many opportunities for such improvements. Inthese techniques there’s always a demand for the running time and the time required for pre-processing.Space requirements for the pre-processing also have a major influence on the running time of thealgorithm. The main focus of the work is to implement landmark technique and to identify the segment of the code in landmark pre-processing which can be parallelized to obtain better speedup. The results are applied to the combined speedup technique which is based on landmarks and containers. The experimental results were compared and analysed for determining better performance improvements in random graphs and planar graphs.

R. Kalpana

2011-02-01

62

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 ony 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

63

Dorsolateral striatal lesions impair navigation based on landmark-goal vectors but facilitate spatial learning based on a "cognitive map".  

Science.gov (United States)

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 also available for standard place learning, or "cognitive mapping," but these cues were valid only within each session, as the position of the platform moved around the pool between sessions together with the intramaze landmark. Animals could therefore learn the position of the platform by taking the consistent vector from the landmark across sessions or by rapidly encoding the new platform position on each session with reference to the extramaze cues. Excitotoxic lesions of the dorsolateral striatum impaired vector-based learning but facilitated cognitive map-based rapid place learning when the extramaze cues were relatively poor (Experiment 1) but not when they were more salient (Experiments 2 and 3). The way the lesion effects interacted with cue availability is consistent with the idea that the memory systems involved in the current navigation task are functionally cooperative yet associatively competitive in nature. PMID:25691518

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

2015-03-01

64

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)

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.

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

65

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

OpenAIRE

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 radio...

Ahmine Razi, T.; Eza Sighari Deljavan, Ali R.

2013-01-01

66

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

Energy Technology Data Exchange (ETDEWEB)

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.)

Ritter, M.

2007-04-27

67

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 rdiologists 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

68

Landmark-based shape analysis of the archaic Homo calvarium from Ceprano (Italy).  

Science.gov (United States)

The Ceprano calvarium represents one of the most important sources of information about both the dynamics of the earliest hominid dispersal toward Europe and the evolution of the genus Homo in the early-to-middle Pleistocene. In this paper, the midsagittal vault profile and the 3D frontal bone morphology of Ceprano are investigated comparatively, using landmark coordinates and Procrustes superimposition. In fact, despite the fact that the skull appears partially distorted by diagenetic pressures (thus precluding a comprehensive landmark-based analysis), some aspects of the overall morphology are suitable for consideration in terms of geometric morphometrics. The midsagittal profile shows an archaic shape, comparable with the H. ergaster/erectus range of variation because of the fronto-parietal flattening, the development of the supraorbital and nuchal structures, and the occurrence of a slightly larger occipital bone. By contrast, the frontal bone displays a derived 3D shape that, mostly because of the widening of the frontal squama, appears comparable with the Afro-European variation of the Middle Pleistocene (i.e., H. heidelbergensis/rhodesiensis). Taking into account the unique morphological pattern displayed by Ceprano, its role as a link between early Homo and the Middle Pleistocene populations of Europe and Africa is not falsified. Thus, when aspects of the Ceprano's morphology are described within the analytical framework provided by geometric morphometrics, the relationships between Ceprano and the subsequent Afro-European fossil record are emphasized, suggesting the occurrence of an ancestral stock of H. heidelbergensis/rhodesiensis that is properly represented by the Italian specimen. PMID:17177181

Bruner, Emiliano; Manzi, Giorgio

2007-03-01

69

Bayesian landmark identification in medical images  

Science.gov (United States)

This paper presents a generic and unified method to identify a set of anatomical landmarks of interest within the medical image domains. Landmark identification is important as it provides us with: 1) initial information for registration, 2) navigation and retrieval guidance through the image data, 3) initial models for segmentation, and 4) valuable (though rough) information about the organs/structures of interest. The proposed method initially uses a supervised learning procedure and then improves itself based on the Bayes" theory. The procedure at the first step requires an expert to define a rough roadmap passing through a set of high-contrast landmarks (milestones), and eventually reaching at the structure of interest. The expert is asked to mark the milestones as desired points and a few points around them as undesired points, respectively. Then we estimate Gaussian models for the marked points by which the optimal search area for each desired landmark is determined. The search areas estimated at this step are considered as the segments of the statistical roadmap. An additional set of statistical models along with the above ones are used to form a set of rules to evaluate the points being found during the search procedure. The points that satisfy the rules will be recognized as the landmarks of interest. As the above method is being applied on a set of new patients/cases, a set of valid landmarks of interests becomes available. This new piece of information is then being used to modify the current statistical roadmap based on the Bayes' theory. We have applied the proposed method on T1-weighted brain MRI of 10 epileptic patients to find the landmarks of the hippocampus. In our experiment, six patients formed the training set, and we observed one-step iteration of the Bayesian modification. The method made no false alarms. The overall success rate (average of sensitivity and specificity) of the algorithm was 83.3% with an accuracy of 99.2%. In localizing the hippocampus, the proposed method (with almost perfect results) was 600 times faster than the mutual information registration (with poor and partly wrong results).

Siadat, Mohammad-Reza; Soltanian-Zadeh, Hamid; Fotouhi, Farshad; Elisevich, Kost

2004-05-01

70

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

OpenAIRE

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...

Fry, S. N.; Wehner, R.

2005-01-01

71

Fiber feature map based landmark initialization for highly deformable DTI registration.  

Science.gov (United States)

This paper presents a novel pipeline for the registration of diffusion tensor images (DTI) with large pathological variations to normal controls based on the use of a novel feature map derived from white matter (WM) fiber tracts. The research presented aims towards an atlas based DTI analysis of subjects with considerable brain pathologies such as tumors or hydrocephalus. In this paper, we propose a novel feature map that is robust against variations in WM fiber tract integrity and use these feature maps to determine a landmark correspondence using a 3D point correspondence algorithm. This correspondence drives a deformation field computed using Gaussian radial basis functions(RBF). This field is employed as an initialization to a standard deformable registration method like demons. We present early preliminary results on the registration of a normal control dataset to a dataset with abnormally enlarged lateral ventricles affected by fatal demyelinating Krabbe disease. The results are analyzed based on a regional tensor matching criterion and a visual assessment of overlap of major WM fiber tracts. While further evaluation and improvements are necessary, the results presented in this paper highlight the potential of our method in handling registration of subjects with severe WM pathology. PMID:24353392

Gupta, Aditya; Toews, Matthew; Janardhana, Ravikiran; Rathi, Yogesh; Gilmore, John; Escolar, Maria; Styner, Martin

2013-03-13

72

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

OpenAIRE

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...

Michaelsen, Eckart

2012-01-01

73

Comparing the Effectiveness of GPS-Enhanced Voice Guidance for Pedestrians with Metric- and Landmark-Based Instruction Sets  

Science.gov (United States)

This paper reports on a field experiment comparing two different kinds of verbal turn instructions in the context of GPS-based pedestrian navigation. The experiment was conducted in the city of Salzburg with 20 participants. Both instruction sets were based on qualitative turn direction concepts. The first one was enhanced with metric distance information and the second one was enhanced with landmark-anchored directions gathered from participants of a previous field experiment. The results show that in context of GPS-enhanced pedestrian navigation both kinds of instruction sets lead to similar navigation performance. Results also demonstrate that effective voice-only guidance of pedestrians in unfamiliar environments at a minimal error rate and without stopping the walk is feasible. Although both kinds of instructions lead to similar navigation performance, participants clearly preferred landmark-enhanced instructions.

Rehrl, Karl; Häusler, Elisabeth; Leitinger, Sven

74

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

OpenAIRE

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 t...

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

2009-01-01

75

Anatomically based lower limb nerve model for electrical stimulation  

Directory of Open Access Journals (Sweden)

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.

Soboleva Tanya K

2007-12-01

76

Group-wise FMRI activation detection on DICCCOL landmarks.  

Science.gov (United States)

Group-wise activation detection in task-based fMRI has been widely used because of its robustness to noises and its capacity to deal with variability of individual brains. However, current group-wise fMRI activation detection methods typically rely on the co-registration of individual brains' fMRI images, which has difficulty in dealing with the remarkable anatomic variation of different brains. As a consequence, the resulted misalignments could significantly degrade the required inter-subject correspondences, thus substantially reducing the sensitivity and specificity of group-wise fMRI activation detection. To deal with these challenges, this paper presents a novel approach to detecting group-wise fMRI activation on our recently developed and validated Dense Individualized and Common Connectivity-based Cortical Landmarks (DICCCOL). The basic idea here is that the first-level general linear model (GLM) analysis is first performed on the fMRI signal of each corresponding DICCCOL landmark in individual brain's own space, and then the estimated effect sizes of the same landmark from a group of subjects are statistically assessed with the mixed-effect model at the group level. Finally, the consistently activated DICCCOL landmarks are determined and declared in a group-wise fashion in response to external block-based stimuli. Our experimental results have demonstrated that the proposed approach can detect meaningful activations. PMID:24777386

Lv, Jinglei; Guo, Lei; Zhu, Dajiang; Zhang, Tuo; Hu, Xintao; Han, Junwei; Liu, Tianming

2014-10-01

77

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-RP 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.

78

[Therapy for systemic metabolic disorders based on the detection of basic corneal landmarks in childhood].  

Science.gov (United States)

Many systemic lysosomal storage disorders show basic corneal opacities already in childhood. The lysosome is a cell organelle, produced by Golgi's apparatus, that is surrounded by a membrane and contains hydrolytic enzymes that break down food molecules, especially proteins and other complex molecules. The ophthalmologist's precise diagnosis of corneal clouding at the slit-lamp may reveal the correct interpretation of the specific lysosomal storage disorder. It is very important to diagnose such diseases as soon as possible because today the development of systemic enzymatic therapies has broadened the therapeutic armamentarium for the current standard of care. The following corneal landmarks of systemic storage diseases and of the modern systemic therapy are presented: cornea verticillata in Fabry's disease, periodic infusion of alpha-galactosidase a; Kayser-Fleischer's ring in Wilson's disease, zinc, trienetin, low copper diet; multiple, punctiform crystals in cystinosis, cysteamine, Raptor RP 103(DR cysteamine) that reduces the cytotoxity in form of continous dissolving of cystine from lysosome, renal transplantation, haematopoietic stem cell transplantation; peripheral ring, but not true lipid arc, and moderate stromal haze in LCAT-deficiency, injection of recombinant enzyme or of encapsulated LCAT-secreting cells; diffuse stromal haze in mucopolysaccharidoses (MPS). Enzyme replacement therapy is currently indicated for MPS I, MPS II, and MPS VI, haematopoietic stem cell transplantation; painful, bilateral pseudo-dendritic opacities in tyrosinemia type II (eponym: Richner-Hanhart syndrome), low phenylalanine and tyrosine diet result in complete disappearance of corneal alterations with a consecutive painfree period. Strict diet during the whole life is necessary to prevent corneal recurrences and the occurrence of palmo-plantar keratoses. Such therapies can enable the patient to lead an otherwise normal life for decades. PMID:23794426

Lisch, W; Pitz, S; Geerling, G

2013-06-01

79

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)

Full Text Available SciELO Chile | Language: English Abstract in spanish 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.

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

2013-06-01

80

A Practical Subspace Approach To Landmarking  

Directory of Open Access Journals (Sweden)

Full Text Available A probabilistic, maximum aposteriori approach to finding landmarks in a face image is proposed, which provides a theoretical framework for template based landmarkers. One such landmarker, based on a likelihood ratio detector, is discussed in detail. Special attention is paid to training and implementation issues, in order to minimize storage and processing requirements. In particular a fast approximate singular value decomposition method is proposed to speed up the training process and implementation of the landmarker in the Fourier domain is presented that will speed up the search process. A subspace method for outlier correction and an iterative implementation of the landmarker are both shown to improve its accuracy. The impact of carefully tuning the many parameters of the method is illustrated. The method is extensively tested and compared with alternatives.

Gert Beumer

2010-06-01

81

Landmark Main Idea  

Science.gov (United States)

In this lesson, students will use key details to determine the main idea of informational text about landmarks. For the summative assessment, students will work in small groups to read an informational text about landmarks, fill out a Main Idea Pyramid Graphic Organizer, and then create a poster in the shape of the landmark they read about. Students will utilize the information on their graphic organizer when creating their poster.

Amanda Shipley

2012-07-23

82

Evaluation of lesion detectability for anatomical-based MAP image reconstruction methods using computer observer study  

International Nuclear Information System (INIS)

In this study, we evaluate lesion detection performance of the anatomical-based maximum a posteriori (MAP) image reconstruction methods in emission computed tomography using the computer observer model. In lesion detection tasks, the conventional anatomical-MAP reconstruction methods cannot preserve lesions not present in the anatomical image with high contrast and, at the same time, suppress noise in the background regions. We previously proposed a new anatomical-MAP reconstruction method, called the SOS-MAP method, based on the spots-on-smooth image model by which the image is modeled by the sum of the smooth background image and the sparse spot image, and showed that the SOS-MAP method can overcome the above-mentioned drawback of the conventional anatomical-MAP methods. However, lesion detection performance of the SOS-MAP method is not still clear. This paper investigates, through the computer observer study, the lesion detection performance of the SOS-MAP method, and shows that the lesion detectability of the SOS-MAP method is superior to that of the conventional anatomical-MAP methods. (author)

83

Evaluation of pelvic lymph node coverage of conventional radiotherapy fields based on bony landmarks in Chinese cervical cancer patients using CT simulation  

OpenAIRE

Objective: To evaluate the pelvic lymph node coverage of conventional pelvic fields based on bony landmarks in Chinese patients with cervical cancer by using computed tomography (CT) simulation images to contour pelvic vessels as substitutes for lymph nodes location. Methods: A retrospective review of CT simulation images and conventional pelvic radiation planning data sets was performed in 100 patients with cervical cancer at the International Federation of Gynecology and Obstetrics (FIGO) S...

Zhang, Xiang; Yu, Hua

2009-01-01

84

Magnetic resonance imaging based rectal cancer classification: landmarks and technical standardization.  

Science.gov (United States)

Rectal cancer classification is important to determine the preoperative chemoradiation therapy and to select appropriate surgical technique. We reviewed the Western and Japanese rectal cancer classification and we propose our new classification based of Magnetic resonance imaging (MRI). We determine the relation of the tumor to fixed parameters in MRI, which are peritoneal reflection and levator ani muscle. Then, we classify the rectal cancer into four levels based on tumor distal margin and invasion to MRI parameters. We applied all three classifications to 60 retrospectively collected patients of different rectal cancer distance and we compared our classifications to the others. Based on each level we standardize our surgical approach. For stages?I-III, We found that level?I?where tumor distal margin is located above the peritoneal reflection and all of them were received low anterior resection (LAR) without chemoradiation. Level II where tumor distal margin is located from the peritoneal reflection and above the levator ani insertion on the rectum. 90% of them were received LAR ± chemoradiation. Level III where tumor distal margin is located at the level of levator ani insertion or invading any part of the levator ani. 60% of them had ULAR + coloanal anastomosis ± chemoradiation. Level IV where the tumor distal margin is located below the levator ani insertion; 77% were received APR ± chemoradiation. The overall kappa for all levels between surgeons and radiologist was 0.93 (95%CI: 0.87-0.99), which is indicating almost perfect agreement. We concluded that the management of rectal tumors differed among each tumor level and our new MRI based classification might facilitate the prediction of surgical and chemoradiation management with better communication among a multidisciplinary team comparing to other classifications. PMID:25593457

Alasari, Sami; Lim, Daero; Kim, Nam Kyu

2015-01-14

85

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 landma priori knowledge - in terms of few landmarks - provided by a human expert into a non-rigid registration process. (orig.)

86

Optimal landmarks selection and fiducial marker placement for minimal target registration error in image-guided neurosurgery  

Science.gov (United States)

We describe a new framework and method for the optimal selection of anatomical landmarks and optimal placement of fiducial markers in image-guided neurosurgery. The method allows the surgeon to optimally plan the markers locations on routine diagnostic images before preoperative imaging and to intraoperatively select the fiducial markers and the anatomical landmarks that minimize the Target Registration Error (TRE). The optimal fiducial marker configuration selection is performed by the surgeon on the diagnostic image following the target selection based on a visual Estimated TRE (E-TRE) map. The E-TRE map is automatically updated when the surgeon interactively adds and deletes candidate markers and targets. The method takes the guesswork out of the registration process, provides a reliable localization uncertainty error for navigation, and can reduce the localization error without additional imaging and hardware. Our clinical experiments on five patients who underwent brain surgery with a navigation system show that optimizing one marker location and the anatomical landmarks configuration reduces the average TRE from 4.7mm to 3.2mm, with a maximum improvement of 4mm. The reduction of the target registration error has the potential to support safer and more accurate minimally invasive neurosurgical procedures.

Shamir, Reuben R.; Joskowicz, Leo; Shoshan, Yigal

2009-02-01

87

Computed tomography landmark-based semi-automated mesh morphing and mapping techniques: Generation of patient specific models of the human pelvis without segmentation.  

Science.gov (United States)

Current methods for the development of pelvic finite element (FE) models generally are based upon specimen specific computed tomography (CT) data. This approach has traditionally required segmentation of CT data sets, which is time consuming and necessitates high levels of user intervention due to the complex pelvic anatomy. The purpose of this research was to develop and assess CT landmark-based semi-automated mesh morphing and mapping techniques to aid the generation and mechanical analysis of specimen-specific FE models of the pelvis without the need for segmentation. A specimen-specific pelvic FE model (source) was created using traditional segmentation methods and morphed onto a CT scan of a different (target) pelvis using a landmark-based method. The morphed model was then refined through mesh mapping by moving the nodes to the bone boundary. A second target model was created using traditional segmentation techniques. CT intensity based material properties were assigned to the morphed/mapped model and to the traditionally segmented target models. Models were analyzed to evaluate their geometric concurrency and strain patterns. Strains generated in a double-leg stance configuration were compared to experimental strain gauge data generated from the same target cadaver pelvis. CT landmark-based morphing and mapping techniques were efficiently applied to create a geometrically multifaceted specimen-specific pelvic FE model, which was similar to the traditionally segmented target model and better replicated the experimental strain results (R(2)=0.873). This study has shown that mesh morphing and mapping represents an efficient validated approach for pelvic FE model generation without the need for segmentation. PMID:25680299

Salo, Zoryana; Beek, Maarten; Wright, David; Marisa Whyne, Cari

2015-04-13

88

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

DEFF Research Database (Denmark)

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.

Zhang, Yan-Ling; Chang, Shi-Jie

2015-01-01

89

MRI-based anatomical model of the human head for specific absorption rate mapping  

OpenAIRE

In this study, we present a magnetic resonance imaging (MRI)-based, high-resolution, numerical model of the head of a healthy human subject. In order to formulate the model, we performed quantitative volumetric segmentation on the human head, using T1-weighted MRI. The high spatial resolution used (1 × 1 × 1 mm3), allowed for the precise computation and visualization of a higher number of anatomical structures than provided by previous models. Furthermore, the high spatial resolution allowe...

Makris, Nikos; Angelone, Leonardo; Tulloch, Seann; Sorg, Scott; Kaiser, Jonathan; Kennedy, David; Bonmassar, Giorgio

2008-01-01

90

Parcellation of the human substantia nigra based on anatomical connectivity to the striatum?  

OpenAIRE

Substantia nigra/ventral tegmental area (SN/VTA) subregions, defined by dopaminergic projections to the striatum, are differentially affected by health (e.g. normal aging) and disease (e.g. Parkinson's disease). This may have an impact on reward processing which relies on dopaminergic regions and circuits. We acquired diffusion tensor imaging (DTI) with probabilistic tractography in 30 healthy older adults to determine whether subregions of the SN/VTA could be delineated based on anatomical c...

Chowdhury, R.; Lambert, C.; Dolan, R. J.; Du?zel, E.

2013-01-01

91

City of Chicago Landmarks  

Science.gov (United States)

The city of Chicago has many hundreds of wonderful architectural landmarks and this helpful website is a great resource for anyone with an interest in such matters. On the site, visitors can start by checking out the Landmarks Tours to get started. There over a dozen tours here, including Mansions Tour, Art Deco Tour, and Pre-Fire Chicago Tour. Moving on, visitors may also wish to look over the Architects area. Here they will encounter some of the usual suspects (Frank Lloyd Wright, Louis Sullivan, etc.) and learn about some lesser-known architects, such as Solon S. Beman and William W. Boyington, who designed the wonderful entrance to Rosehill Cemetery. The Style Guide offers a great primer for those who'd like to know more about two dozen architectural styles, including Craftsman, International, and Tudor Revival. Finally, the site also includes a Listings area, complete with information about all of the buildings on the city's official landmarks list.

92

Temperature elevation in the eye of anatomically based human head models for plane-wave exposures  

International Nuclear Information System (INIS)

This study investigated the temperature elevation in the eye of anatomically based human head models for plane-wave exposures. The finite-difference time-domain method is used for analyzing electromagnetic absorption and temperature elevation. The eyes in the anatomic models have average dimensions and weight. Computational results show that the ratio of maximum temperature in the lens to the eye-average SAR (named 'heating factor for the lens') is almost uniform (0.112-0.147 deg. C kg W-1) in the frequency region below 3 GHz. Above 3 GHz, this ratio increases gradually with an increase of frequency, which is attributed to the penetration depth of an electromagnetic wave. Particular attention is paid to the difference in the heating factor for the lens between this study and earlier works. Considering causes clarified in this study, compensated heating factors in all these studies are found to be in good agreement

93

Anatomical-based defense responses of Scots pine (Pinus sylvestris) stems to two fungal pathogens.  

Science.gov (United States)

We investigated the cellular responses of stem tissues of mature Scots pine (Pinus sylvestris L.) trees to inoculations with two fungal pathogens. The bark beetle vectored fungus, Leptographium wingfieldii Morelet, induced longer lesions in the bark, stronger swelling of polyphenolic parenchyma cells, more polyphenol accumulation and increased ray parenchyma activity compared with the root rot fungus, Heterobasidion annosum (Fr.) Bref., or mechanical wounding. Axial resin ducts in the xylem are a general feature of the preformed defenses of Scots pine, but there was no clear induction of additional traumatic axial resin ducts in response to wounding or fungal infection. The anatomical responses of Scots pine to pathogen infection were localized to the infection site and were attenuated away from bark lesions. The responses observed in Scots pine were compared with published studies on Norway spruce (Picea abies (L.) Karst.) for which anatomically based defense responses have been well characterized. PMID:16356912

Nagy, Nina Elisabeth; Krokene, Paal; Solheim, Halvor

2006-02-01

94

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)

95

New Landmark for the Endoscopic Endonasal Transsphenoidal Approach of Pituitary Surgery  

Science.gov (United States)

Objective To clarify the anatomical correlations of the sphenoid sinus with surrounding structures in the normal Korean population, and to identify surgical landmarks for safe sellar floor dissection in the anterior skull base by endoscopy and microscopy. Methods We reviewed the 196 brain magnetic resonance imaging findings showing a normal appearance, and measured the distances between anatomical landmarks. Results The mean distances from the base of the columella to the anterior wall of the sphenoid sinus and the sellar floor were 69.71±4.25 mm and 86.26±4.57 mm, respectively in the over 15 age group, and showed the smallest degree of variation among the measurements. The mean angles between the floor of the nasal cavity and the straight line connecting the base of the columella and the sellar floor were 29.45±3.25° and 24.75±4.00° in the over 15 and under 15 age groups, respectively. The mean values of both distances and angles increased with age until 15 years after which no further increases were evident. There were no significant differences in the measurements between males and females or among subjects with different degrees of pneumatization in the over 15 age group. Conclusion The distances from the base of the columella to the sellar floor and the anterior wall of the sphenoid sinus, which were consistent among individuals, could be used as a surgical indicator to investigate the sellar floor in endoscopic or microscopic transsphenoidal approaches. PMID:23826477

Kim, Young Ha; Kim, Ju Eun; Kim, Min Joo

2013-01-01

96

Distally based radial forearm flap with preservation of the radial artery: anatomic, experimental, and clinical studies.  

Science.gov (United States)

In this article we report on the anatomical, experimental, and clinical investigations of the distally adipofascial pedicled radial forearm flap based on the small perforators around the radial styloid process. There are about 10 small perforators (0.3-0.5 mm in diameter) from the distal radial artery around the radial styloid process. The longitudinal chain-linked vascular plexuses (suprafascial, paraneural, and perivenous) formed by the forearm ascending and descending branches of septofasciocutaneous perforators meet and cross over with the transverse carpal vascular plexuses around the radial styloid region. Based on these directional-oriented plexuses, distally based adipofascial pedicled radial forearm fasciocutaneous and adipofascial flaps were designed and successfully applied in 34 clinical cases. The pivot point was located at 1-2 cm above the radial styloid. The skin island plus adipofascial pedicle measured between 9-18 cm in length, with the adipofascial pedicle 3-4 cm in width. The length-to-width ratio is 3-5:1. The venous drainage of this distally based flap was investigated anatomically and experimentally. The cephalic vein has no positive role for venous drainage in distally based flaps. The difference between distally based flaps and reverse-flow flaps, clinical selection of fasciocutaneous and adipofascial flaps, advantages and disadvantages, and technical tips for operative success are discussed. PMID:12942523

Chang, Shi-Min; Hou, Chun-Lin; Zhang, Feng; Lineaweaver, William C; Chen, Zhong-Wei; Gu, Yu-Dong

2003-01-01

97

Coexistence of the suprascapular notch and the suprascapular foramen--a rare anatomical variation and a new hypothesis on its formation based on anatomical and radiological studies.  

Science.gov (United States)

The suprascapular notch is the most common site of suprascapular nerve entrapment, which can manifest in disability and pain of the upper limb. Here, we present three cases of a very rare anatomical variation in the suprascapular region: the coexistence of the suprascapular notch and the suprascapular foramen. The variation was found during radiological and anatomical investigations. The suprascapular foramen was situated inferior to the suprascapular notch. A bony bridge lay between them, likely created by an ossified anterior coracoscapular ligament (ACSL). This anatomical variation probably increased the risk of suprascapular nerve entrapment by nerve irritation of the bony margins during passsage through the foramen and by a lack of the elasticity that the ACSL normally demonstrates. Also, a bony bridge passing through the middle part of the suprascapular notch reduces the space available for nerve passage (bony bridge decreases the space by about 36.5-38.6 %). One patient who underwent the radiological study had typical symptoms of suprascapular nerve entrapment. Based on his medical history and the presence of this rare variation of the suprascapular notch at the suprascapular region we suspect this neuropathy. PMID:23208271

Polguj, Micha?; J?drzejewski, Kazimierz; Majos, Agata; Topol, Miros?aw

2013-06-01

98

Early fetal anatomical sonography.  

LENUS (Irish Health Repository)

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.

Donnelly, Jennifer C

2012-10-01

99

Ordered Landmarks in Planning  

CERN Document Server

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...

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

2011-01-01

100

Age-related changes in anatomic bases for the insertion of zygomatic implants.  

Science.gov (United States)

The objectives of this study were to verify whether Chinese patients are well-suited for zygomatic implantation and to observe age-related changes in the linear and angular anatomic bases of the maxilla and zygoma. Using three-dimensional images selected from maxillofacial cone beam computed tomography (CBCT) scans generated by SimPlant, linear and angular measurements were obtained by simulating zygomatic implantation. The edentulous group comprised 40 subjects aged between 62 and 65 years. A total of 120 dentate cases were divided into three groups based on age: the established occlusion group (n=40; 12-15 years old), the adult group (n=40; 37-40 years old), and the elderly group (n=40; 62-65 years old). The mean potential insertion length of the ordinary and additional zygomatic implants became longer with age in the dentate groups. For both zygomatic implant insertion areas, the anteroposterior lengths of the maxilla and zygoma were thicker in the older dentate groups (Pdifferences were verified in the installation direction among the dentate groups. Gender was not a significant factor. The zygomatic skeleton changes with age, which results in linear and angular variations in the zygomatic implant insertion area. Therefore, the anatomic bases in Chinese adults are suitable for zygomatic implants. PMID:24951178

Pu, L-F; Tang, C-B; Shi, W-B; Wang, D-M; Wang, Y-Q; Sun, C; Yao, W-Q; Wu, Y-N

2014-11-01

101

CT characteristics of extra-organic primary tumor in pelvis and the anatomic bases  

International Nuclear Information System (INIS)

Objective: To analyze the CT contrast enhanced features of the extra-organic primary tumors in pelvis and to evaluate anatomic bases of these imaging characteristics. Methods: CT findings in 14 patients with pathologically proved extra-organic primary tumors in pelvis were reviewed retrospectively for tumor size, density, margins, contrast enhanced characteristics, location and relationship of the lesions with surrounding organs and tissues. Results: There were benign tumors (n=3) and malignant tumors (n=11) in this study. There were 6 lesions in peritoneal cavity and 6 in retroperitoneal space of pelvis respectively, and two other masses were in both peritoneal cavity and retroperitoneal space of pelvis. CT scan revealed that there were 6 solid masses and 8 cystic-solid masses. The enhanced characteristics of lesions were homogeneous and heterogeneous in 3 and 11 patients respectively. The fatty space surrounding the lesion was invasive in 7 cases and all of them were malignant tumor. The fatty space surrounding lesion was clear in other 7 cases including 3 benign tumors and 4 malignant tumors. CT revealed calcification in 4 lesions including benign teratoma (n=2), malignant teratoma (n=1), and carcinoid (n=1). Conclusion: In the diagnosis of extra-organic primary tumors in pelvis, CT enhancement scan can reveal the anatomic location and relationships of the lesions with surrounding organs and tissues and can differentiate benign and malignant tumor to some degreenign and malignant tumor to some degree

102

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

103

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

104

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

DEFF Research Database (Denmark)

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.

Fagertun, Jens; Harder, Stine

2014-01-01

105

Gross feature recognition of Anatomical Images based on Atlas grid (GAIA): Incorporating the local discrepancy between an atlas and a target image to capture the features of anatomic brain MRI.  

Science.gov (United States)

We aimed to develop a new method to convert T1-weighted brain MRIs to feature vectors, which could be used for content-based image retrieval (CBIR). To overcome the wide range of anatomical variability in clinical cases and the inconsistency of imaging protocols, we introduced the Gross feature recognition of Anatomical Images based on Atlas grid (GAIA), in which the local intensity alteration, caused by pathological (e.g., ischemia) or physiological (development and aging) intensity changes, as well as by atlas-image misregistration, is used to capture the anatomical features of target images. As a proof-of-concept, the GAIA was applied for pattern recognition of the neuroanatomical features of multiple stages of Alzheimer's disease, Huntington's disease, spinocerebellar ataxia type 6, and four subtypes of primary progressive aphasia. For each of these diseases, feature vectors based on a training dataset were applied to a test dataset to evaluate the accuracy of pattern recognition. The feature vectors extracted from the training dataset agreed well with the known pathological hallmarks of the selected neurodegenerative diseases. Overall, discriminant scores of the test images accurately categorized these test images to the correct disease categories. Images without typical disease-related anatomical features were misclassified. The proposed method is a promising method for image feature extraction based on disease-related anatomical features, which should enable users to submit a patient image and search past clinical cases with similar anatomical phenotypes. PMID:24179864

Qin, Yuan-Yuan; Hsu, Johnny T; Yoshida, Shoko; Faria, Andreia V; Oishi, Kumiko; Unschuld, Paul G; Redgrave, Graham W; Ying, Sarah H; Ross, Christopher A; van Zijl, Peter C M; Hillis, Argye E; Albert, Marilyn S; Lyketsos, Constantine G; Miller, Michael I; Mori, Susumu; Oishi, Kenichi

2013-01-01

106

Synchrotron-based phase-contrast images of zebrafish and its anatomical structures  

Science.gov (United States)

Images of vertebrates (zebrafish and zebrafish eye) have been obtained by using an X-ray phase-contrast imaging technique, namely, synchrotron-based diffraction-enhanced imaging (SY-DEI) (or analyzer based imaging) and synchrotron-based diffraction imaging in tomography mode (SY-DEI-CT). Due to the limitations of the conventional radiographic imaging in visualizing the internal complex feature of the sample, we utilized the upgraded SY-DEI and SY-DEI-CT systems to acquire the images at 20, 30 and 40 keV, to observe the enhanced contrast. SY-DEI and SY-DEI-CT techniques exploits the refraction properties, and have great potential in studies of soft biological tissues, in particular for low (Z) elements, such as, C, H, O and N, which constitutes the soft tissue. Recently, these techniques are characterized by its extraordinary image quality, with improved contrast, by imaging invertebrates. We have chosen the vertebrate sample of zebrafish (Danio rerio), a model organism widely used in developmental biology and oncology. For biological imaging, these techniques are most sensitive to enhance the contrast. For the present study, images of the sample, in planar and tomography modes offer more clarity on the contrast enhancement of anatomical features of the eye, especially the nerve bundle, swim bladder, grills and some internal organs in gut with more visibility.

Rao Donepudi, Venkateswara; Melumai, Bhaskaraiah; Thallapaka, Balasaidulu; Sandeep, Konam; Cesareo, Roberto; Brunetti, Antonio; Zhong, Zhong; Akatsuka, Takao; Yuasa, Tetsuya; Takeda, Tohoru; Gigante, Giovanni E.

2014-08-01

107

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.)

108

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)

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.

Queenilyn B. Albutra

2012-06-01

109

Alignment of CT images of skull dysmorphology using anatomy-based perpendicular axes  

International Nuclear Information System (INIS)

Rigid body registration of 3D CT scans, based on manual identification of homologous landmarks, is useful for the visual analysis of skull dysmorphology. In this paper, a robust and simple alignment method was proposed to allow for the comparison of skull morphologies, within and between individuals with craniofacial anomalies, based on 3D CT scans, and the minimum number of anatomical landmarks, under rigidity and uniqueness constraints. Three perpendicular axes, extracted from anatomical landmarks, define the absolute coordinate system, through a rigid body transformation, to align multiple CT images for different patients and acquisition times. The accuracy of the alignment method depends on the accuracy of the localized landmarks and target points. The numerical simulation generalizes the accuracy requirements of the alignment method. Experiments using a human dried skull specimen, and ten sets of skull CT images (the pre- and post-operative CT scans of four plagiocephaly, and one fibrous dysplasia patients), demonstrated the feasibility of the technique in clinical practice

110

Alignment of CT images of skull dysmorphology using anatomy-based perpendicular axes  

Energy Technology Data Exchange (ETDEWEB)

Rigid body registration of 3D CT scans, based on manual identification of homologous landmarks, is useful for the visual analysis of skull dysmorphology. In this paper, a robust and simple alignment method was proposed to allow for the comparison of skull morphologies, within and between individuals with craniofacial anomalies, based on 3D CT scans, and the minimum number of anatomical landmarks, under rigidity and uniqueness constraints. Three perpendicular axes, extracted from anatomical landmarks, define the absolute coordinate system, through a rigid body transformation, to align multiple CT images for different patients and acquisition times. The accuracy of the alignment method depends on the accuracy of the localized landmarks and target points. The numerical simulation generalizes the accuracy requirements of the alignment method. Experiments using a human dried skull specimen, and ten sets of skull CT images (the pre- and post-operative CT scans of four plagiocephaly, and one fibrous dysplasia patients), demonstrated the feasibility of the technique in clinical practice.

Yoo, Sun K [Department of Medical Engineering, Yonsei University College of Medicine, Seoul (Korea, Republic of); Kim, Yong O [Department of Plastic and Reconstructive Surgery, Yonsei University College of Medicine, Institute of Human Tissue Restoration, Seoul (Korea, Republic of); Kim, Hee-Joung [Department of Diagnostic Radiology, Yonsei University College of Medicine, Seoul (Korea, Republic of); Kim, Nam H [Department of Medical Engineering, Yonsei University College of Medicine, Seoul (Korea, Republic of); Jang, Young Beom [Department of Information and Telecommunication Engineering, Sangmyung University, Cheoan (Korea, Republic of); Kim, Kee-Deog [Department of Oral and Maxillofacial Radiology, Yonsei University College of Dentistry, Seoul (Korea, Republic of); Lee, Hye-Yeon [Department of Anatomy, Yonsei University College of Medicine, Seoul (Korea, Republic of)

2003-08-21

111

Alignment of CT images of skull dysmorphology using anatomy-based perpendicular axes  

Science.gov (United States)

Rigid body registration of 3D CT scans, based on manual identification of homologous landmarks, is useful for the visual analysis of skull dysmorphology. In this paper, a robust and simple alignment method was proposed to allow for the comparison of skull morphologies, within and between individuals with craniofacial anomalies, based on 3D CT scans, and the minimum number of anatomical landmarks, under rigidity and uniqueness constraints. Three perpendicular axes, extracted from anatomical landmarks, define the absolute coordinate system, through a rigid body transformation, to align multiple CT images for different patients and acquisition times. The accuracy of the alignment method depends on the accuracy of the localized landmarks and target points. The numerical simulation generalizes the accuracy requirements of the alignment method. Experiments using a human dried skull specimen, and ten sets of skull CT images (the pre- and post-operative CT scans of four plagiocephaly, and one fibrous dysplasia patients), demonstrated the feasibility of the technique in clinical practice.

Yoo, Sun K.; Kim, Yong O.; Kim, Hee-Joung; Kim, Nam H.; Jang, Young Beom; Kim, Kee-Deog; Lee, Hye-Yeon

2003-08-01

112

Conversion coefficients based on the VIP-Man anatomical model and EGS4.  

Science.gov (United States)

A new set of conversion coefficients from kerma free-in-air to absorbed dose and kerma free-in-air to "effective VIP-Man dose" has been calculated for external monoenergetic photon beams from 10 keV to 10 MeV using an image-based whole-body anatomical model. This model, called VIP-Man, was recently developed at Rensselaer from the high-resolution color images of the National Library of Medicine's Visible Human Project. An EGS4-based Monte Carlo user code, named EGS4-VLSI, was developed to efficiently process the extremely large image data in VIP-Man. Irradiation conditions include anterior-posterior, posterior-anterior, right lateral, left lateral, rotational, and isotropic geometries. Conversion coefficients from this study are compared with those obtained from two mathematical models, ADAM and EVA. "Effective VIP-Man doses" differ from the previously reported effective dose results by 10%-50% for photons between 100 keV and 10 MeV. Discrepancies are more significant at lower energies and for individual organ doses. Since VIP-Man is a realistic model that contains several tissues that were not previously defined well (or not available) in other models, the reported results offer an opportunity to improve the existing dosimetric data and the mathematical models. PMID:11480875

Chao, T C; Bozkurt, A; Xu, X G

2001-08-01

113

New optimization algorithm for the anatomical-based MAP image reconstruction using joint entropy  

International Nuclear Information System (INIS)

Recently, a maximum a posteriori image reconstruction method (MAP-JE), which uses sparsity of the joint histogram of an emission CT image and its corresponding anatomical image as a priori knowledge, was proposed for emission CT. The conventional MAP-JE methods use gradient-based methods to minimize the cost function including the non-convex joint entropy so that the image quality of the conventional MAP-JE methods depends highly on the free parameters that affect non-convexity of the cost function, such as the bin width of the joint histogram and the width of the Parzen window function. In this paper, we propose a new optimization algorithm with less number of free parameters for the MAP-JE reconstruction, which is developed based on the optimization technique called the surrogate function method. We show through computer simulation studies that the proposed algorithm is less sensitive to the free parameters than the conventional method and generates stably the reconstructed image reflecting the a priori knowledge. (author)

114

ANATOMICAL PRINCIPLES BEHIND PRESERVATION OF LARYNGEAL NERVES DURING THYROIDECTOMY  

Directory of Open Access Journals (Sweden)

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

O. Fabian

2011-08-01

115

Global and local spatial landmarks: their role during foraging by Columbian ground squirrels (Spermophilus columbianus).  

Science.gov (United States)

Locating food and refuge is essential for an animal's survival. However, little is known how mammals navigate under natural conditions and cope with given environmental constraints. In a series of six experiments, I investigated landmark-based navigation in free-ranging Columbian ground squirrels (Spermophilus columbianus). Squirrels were trained individually to find a baited platform within an array of nine identical platforms and artificial landmarks set up on their territories. After animals learned the location of the food platform in the array, the position of the latter with respect to local artificial, local natural, and global landmarks was manipulated, and the animal's ability to find the food platform was tested. When only positions of local artificial landmarks were changed, squirrels located food with high accuracy. When the location of the array relative to global landmarks was altered, food-finding accuracy decreased but remained significant. In the absence of known global landmarks, the presence of a familiar route and natural local landmarks resulted in significant but not highly accurate performance. Squirrels likely relied on multiple types of cues when orienting towards a food platform. Local landmarks were used only as a secondary mechanism of navigation, and were not attended to when a familiar route and known global landmarks were present. This study provided insights into landmark use by a wild mammal in a natural situation, and it demonstrated that an array of platforms can be employed to investigate landmark-based navigation under such conditions. PMID:16163480

Vlasak, Anna N

2006-01-01

116

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

OpenAIRE

In present study external morphology, leaf epidermal anatomy and pollen structureof three species of genus Setaria(Poaceae)viz., 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 (SEM)were used to study leaf epidermal anatomy and pollen structure.Palyno-anatomical analysis of genus Setaria shows variations within the species....

Abdul nazir; Mir Ajab Khan; Arshad Mehmood Abbasi; Nadeem Khan; Khalid Ahmed

2014-01-01

117

Age-dependent use of local and global landmarks during escape: experiments using Columbian ground squirrels.  

Science.gov (United States)

How animals utilize their space often changes during ontogeny, perhaps resulting from alternative use of orientation mechanisms. This study investigated whether landmark-based navigation mechanisms were age-dependent in Columbian ground squirrels (Spermophilus columbianus). In field tests, young (1-2 years old) and adult (3-6 years old) animals had to find an escape burrow when either local, global, or both types of landmarks were obstructed. The comparison of escape times between age groups revealed that adult squirrels found escape burrow faster than young animals if global landmarks were available. However, if only local landmarks were present, young squirrels outperformed older animals. The comparison of escape time within each age group showed that obstruction of global or local landmarks lengthened escape time of adult squirrels. In contrast, young animals had longer escapes only when local landmarks were obstructed. The results suggested that the use of different types of landmarks was age specific. PMID:17462833

Nesterova, Anna P

2007-07-01

118

Landmarks GIScience for intelligent services  

CERN Document Server

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

Richter, Kai-Florian

2014-01-01

119

Fast Localization of Facial Landmark Points  

OpenAIRE

The main objective of this work is to develop a method that can accurately estimate the positions of relevant facial landmarks in real-time on hardware with limited processing power, such as modern mobile devices. This is achieved with a sequence of estimators based on ensembles of regression trees. The trees use simple pixel intensity comparisons in their internal nodes and this makes them able to process image regions very fast. We test the developed system on several publ...

Markus?, Nenad; Frljak, Miroslav; Pandz?ic?, Igor S.; Ahlberg, Jo?rgen; Forchheimer, Robert

2014-01-01

120

Automatic localization of fovea in retinal images based on mathematical morphology and anatomic structures  

Directory of Open Access Journals (Sweden)

Full Text Available Diabetic macular edema is one of the retinal abnormalities which affects the central vision of the person and causes total blindness in severe cases. Fovea (center of macula localization is an important step in retinal image analysis especially for grading diabetic macular edema. This paper describes a method to automatically localize the fovea center in retinal fundus images. The method is mainly based on mathematical morphology along with the information of other anatomic structures such as blood vessel and optic disc. Initially, the vascular structure and optic disc center are extracted, and then the morphological operations are employed on the gray scale image of green channel for fovea candidates’ selection. The candidates’ satisfying area, density and distance criteria are considered for the final stage. In the final stage, the candidate having lesser vessel pixels was considered as fovea region. The proposed method was evaluated on the two publicly available DRIVE and STARE databases. The method was able to obtain 100% of fovea localization accuracy on DRIVE database with 2.88 seconds average computation time.

J.Benadict Raja

2014-10-01

121

Coexistence of the suprascapular notch and the suprascapular foramen—a rare anatomical variation and a new hypothesis on its formation based on anatomical and radiological studies  

OpenAIRE

The suprascapular notch is the most common site of suprascapular nerve entrapment, which can manifest in disability and pain of the upper limb. Here, we present three cases of a very rare anatomical variation in the suprascapular region: the coexistence of the suprascapular notch and the suprascapular foramen. The variation was found during radiological and anatomical investigations. The suprascapular foramen was situated inferior to the suprascapular notch. A bony bridge lay between them, li...

Polguj, Micha?; Je?drzejewski, Kazimierz; Majos, Agata; Topol, Miros?aw

2012-01-01

122

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

Directory of Open Access Journals (Sweden)

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.

Beugnon Guy

2011-08-01

123

Personalising population-based respiratory motion models of the heart using neighbourhood approximation based on learnt anatomical features.  

Science.gov (United States)

Respiratory motion models have been proposed for the estimation and compensation of respiratory motion during image acquisition and image-guided interventions on organs in the chest and abdomen. However, such techniques are not commonly used in the clinic. Subject-specific motion models require a dynamic calibration scan that interrupts the clinical workflow and is often impractical to acquire, while population-based motion models are not as accurate as subject-specific motion models. To address this lack of accuracy, we propose a novel personalisation framework for population-based respiratory motion models and demonstrate its application to respiratory motion of the heart. The proposed method selects a subset of the population sample which is more likely to represent the cardiac respiratory motion of an unseen subject, thus providing a more accurate motion model. The selection is based only on anatomical features of the heart extracted from a static image. The features used are learnt using a neighbourhood approximation technique from a set of training datasets for which respiratory motion estimates are available. Results on a population sample of 28 adult healthy volunteers show average improvements in estimation accuracy of 20% compared to a standard population-based motion model, with an average value for the 50th and 95th quantiles of the estimation error of 1.6mm and 4.7 mm respectively. Furthermore, the anatomical features of the heart most strongly correlated to respiratory motion are investigated for the first time, showing the features on the apex in proximity to the diaphragm and the rib cage, on the left ventricle and interventricular septum to be good predictors of the similarity in cardiac respiratory motion. PMID:24972379

Peressutti, Devis; Penney, Graeme P; Kolbitsch, Christoph; King, Andrew P

2014-10-01

124

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

Directory of Open Access Journals (Sweden)

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.

ANDI TANRA TELLU

2005-04-01

125

Anatomical study of perforator arteries in the distally based radial forearm fasciosubcutaneous flap.  

Science.gov (United States)

We investigated the anatomical vascular basis of the forearm fasciosubcutaneous flap (FSC-F), fed by the distal perforator arteries of the fascia. This type of flap was proposed, in hand reconstructive surgery, to avoid the disadvantages caused by axial-pattern reverse radial forearm fasciocutaneous flap, based on ligation and rotation of the radial artery (RA). In eight fresh cadaveric forearms, the RA was injected slowly with acrylic resin and the superficial flexor compartment was dissected. Then the FSC-F was raised from the lateral margins of the sample to the median RA axis, and the collaterals of the RA (number, interval of origin, and caliber) were evaluated. The fascial branches of RA (mean number +/- SD: 20 +/- 3) originated mainly from the radial and ulnar sides of the RA. In the distal forearm the vessels were more numerous (mean value = 11.3 vs. 8.9; Student's t-test, P forearm and anastomosed in the fascial plane, forming longitudinal fan-shaped arterial chains giving rise to the vascular epifascial network. Histological (hematoxylin-eosin, azan-Mallory, Weigert) and immunohistochemical (anti-von Willebrand factor) study of the FSC-F at different levels of sampling was also carried out. The epifascial branches of distal sections were smaller in diameter (78.3 +/- 35.5 microm) than those of intermediate (105.7 +/- 28.7 microm; Newman-Keuls test, P forearm, so that during surgical dissection, the safety distance from the radial styloid should take into account that also in the presence of a sufficient number of vessels in the distal forearm their caliber could be inadequate to the hemodynamic request of the flap. Thus, rather than on a theoretic distance from the radial styloid, the length of the flap should be based on an accurate evaluation of the individual vascularization of the forearm case by case. PMID:15495170

Tiengo, Cesare; Macchi, Veronica; Porzionato, Andrea; Bassetto, Francesco; Mazzoleni, Franco; De Caro, Raffaele

2004-11-01

126

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 targin, 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

127

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

DEFF Research Database (Denmark)

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.

Feragen, Aasa; Petersen, Jens

2015-01-01

128

Anatomical consideration of Dhamani marma in Ayurveda  

OpenAIRE

Ayurveda is an ancient health science devoted to the cure on human suffering and for the care of the health of the people. Injuries involving various types of the structures in the body like dhamanis (arteries), muscles, nerves, bones and the visceral organs in general and when in combination specifying marma. Among the hidden sciences of India, marma science is the most important. Marmas are not superficial landmarks on the body surface but these are deep-seated important physio-anatomical s...

Bhan Pratap Yadaw; Awasthi H H

2014-01-01

129

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

International Nuclear Information System (INIS)

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'' III1) had a more favorable 5-yr survival than did patients with involvement of paraaortic, iliac, or mesenteric nodes (''anatomic substage'' III2) : 93% versus 57%, respectively (p 2, but not of those in stage III1

130

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

Directory of Open Access Journals (Sweden)

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.

MUH RAHMAD SUHARTANTO

2010-01-01

131

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)

132

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

133

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

Energy Technology Data Exchange (ETDEWEB)

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/.

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

134

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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.

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

135

Outline-based morphometrics, an overlooked method in arthropod studies?  

Science.gov (United States)

Modern methods allow a geometric representation of forms, separating size and shape. In entomology, as well as in many other fields involving arthropod studies, shape variation has proved useful for species identification and population characterization. In medical entomology, it has been applied to very specific questions such as population structure, reinfestation of insecticide-treated areas and cryptic species recognition. For shape comparisons, great importance is given to the quality of landmarks in terms of comparability. Two conceptually and statistically separate approaches are: (i) landmark-based morphometrics, based on the relative position of a few anatomical "true" or "traditional" landmarks, and (ii) outline-based morphometrics, which captures the contour of forms through a sequence of close "pseudo-landmarks". Most of the studies on insects of medical, veterinary or economic importance make use of the landmark approach. The present survey makes a case for the outline method, here based on elliptic Fourier analysis. The collection of pseudo-landmarks may require the manual digitization of many points and, for this reason, might appear less attractive. It, however, has the ability to compare homologous organs or structures having no landmarks at all. This strength offers the possibility to study a wider range of anatomical structures and thus, a larger range of arthropods. We present a few examples highlighting its interest for separating close or cryptic species, or characterizing conspecific geographic populations, in a series of different vector organisms. In this simple application, i.e. the recognition of close or cryptic forms, the outline approach provided similar scores as those obtained by the landmark-based approach. PMID:25111609

Dujardin, Jean-Pierre; Kaba, D; Solano, P; Dupraz, M; McCoy, K D; Jaramillo-O, N

2014-12-01

136

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  

OpenAIRE

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, Meram 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...

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

2012-01-01

137

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 IMRTcal 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)

138

An anatomically based finite element model of the lower limbs in the seated posture.  

Science.gov (United States)

In this study an anatomically accurate 3D Finite Element (FE) model of the lower limbs was developed from axial cryosection images of the Visible Man (VM). The relative position of the lower limbs of a subject in standing and sitting positions was acquired with a laser scanner. A subset of these data points were used as control points in a novel application of the Host Mesh Fitting (HMF) technique, where the generic model geometry was morphed to subject data in the standing position, and then this subject-specific model was articulated to the seated posture. The gluteus maximus muscle and a portion of the skin mesh of the customised model were selected to provide a framework with which to examine the mechanics of sitting. Passive material properties were taken from the literature and were implemented in two two-parameter Mooney-Rivlin models to assess the response of the anatomical models to applied forces and pressures. The average deformation of the skin mesh was 0.77+/-1.525 mm which resulted in a maximum von Mises stress of 3.98 kPa. The average deformation of the gluteus maximus mesh was 2.69+/-0.6 mm which produced a maximum von Mises stress of 43 kPa. The results of the von Mises stress distribution support the theory that the highest stress occurs in the region immediately beneath the ischial tuberosities. The results of this research confirm previous conclusions reached using geometrically less complex models and the application of customisation to nonlinear mechanics provides a novel avenue to quantitatively assess office chair design and to analyse the mechanics of sitting. PMID:18003468

Cox, Sarah L; Mithraratne, Kumar; Smith, Nicolas P

2007-01-01

139

Predicting the risk of rupture of intracranial aneurysms based on anatomical location.  

Science.gov (United States)

The location of intracranial aneurysms may be a significant independent risk factor for predicting aneurysm rupture. A recent report found high bleed rates from posterior communicating artery aneurysms which had not previously been noted. On this distinction hangs the decision whether to treat a large number of unruptured aneurysms. In the recent publication by the International Study of Unruptured Intracranial Aneurysms (ISUIA), two bleeds from small incidental posterior communicating artery aneurysms were noted and these aneurysms were reported to have a similar risk to aneurysms of the posterior circulation and as a result were grouped with them. This was a post hoc analysis so the justification for this assertion is tenuous. The hypothesis that posterior communicating aneurysms are of similar risk to posterior circulation aneurysms requires further testing on other data before it can be confidently accepted. A review of the literature was undertaken to define relative risks of rupture for different anatomical locations and to test the above hypothesis. Eleven papers were found to contain sufficient data to calculate rupture rates for anatomical sub groups. Studies contained a total of 30,204 patient years of follow up. Results showed the internal carotid artery to be the commonest site for unruptured aneurysms (38%). Aneurysms located in the posterior circulation had an overall annual bleed rate of 1.8%. This compares with 0.49% for the anterior circulation. The bleed rate from aneurysms of the posterior communicating artery (0.46% per year) was similar to that of the rest of the anterior circulation. The ISUIA post hoc hypothesis fails when tested on these data and the ISUIA data should be re-analysed with posterior communicating artery aneurysms grouped with the anterior circulation where they more traditionally belong. PMID:15662565

Clarke, G; Mendelow, A D; Mitchell, P

2005-03-01

140

'Anatomically-correct' dosimetric parameters may be better predictors for esophageal toxicity than are traditional CT-based metrics  

International Nuclear Information System (INIS)

Purpose: Incidental esophageal irradiation during lung cancer therapy often causes morbidity. There is interest in trying to relate esophageal dosimetric parameters to the risk of injury. These parameters typically rely on CT-defined esophageal contours, and thus systematic limitations in esophageal contouring will influence these parameters. We herein assess the ability of a correction method, based on physiologic principles, to improve the predictive power of dosimetric parameters for radiation-induced esophageal injury. Methods and Materials: Esophageal contours for 236 patients treated for lung cancer were quantitatively analyzed. All patients received three-dimensional planning, and all contours were generated by the same physician on axial CT images. Traditional dose-volume histogram (DVH)-based dosimetric parameters were extracted from the three-dimensional data set. A second set of 'anatomically correct' dosimetric parameters was derived by adjusting the contours to reflect the known shape of the esophagus. Each patient was scored for acute and late toxicity using ROTG criteria. Univariate analysis was used to assess the predictive power of corrected and uncorrected dosimetric parameters (e.g., mean dose, V 50, and V 60) for toxicity. The p values were taken as a measure of their significance. Results: The univariate results indicate that both corrected and uncorrected dosimetric parameters are generally predictors for toxicity. The correnerally predictors for toxicity. The corrected parameters are more highly correlated (lower p value) with outcomes than the uncorrected metrics. Conclusions: The inclusion of corrections, based on anatomic realities, to DVH-based dosimetric parameters may provide dosimetric parameters that are better correlated with clinical outcomes than are traditional DVH-based metrics

141

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)

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.

Goffinet François

2011-10-01

142

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

Directory of Open Access Journals (Sweden)

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.

Giannelli, Alberto

2011-12-01

143

Fluence-to-dose conversion coefficients for monoenergetic proton beams based on the VIP-Man anatomical model  

International Nuclear Information System (INIS)

A new set of fluence-to-absorbed dose and fluence-to-effective dose conversion coefficients has been calculated for high-energy protons using the whole-body anatomical model VIP-Man, which was developed from the high-resolution transverse colour photographic images of the National Library of Medicine's Visible Human Project. For 10 monoenergetic proton beams between 20 and 10,000 MeV, organ dose calculations were performed using the Monte Carlo code MCNPX under six different irradiation geometries: anterior-posterior, posterior-anterior, left lateral, right lateral, isotropic and rotational. The absorbed dose results for 24 major organs of VIP-Man are presented and compared with those based on mathematical phantoms reported in the literature. The discrepancies (generally within 40%) in organ dose and effective dose estimates are attributed to the use of different transport models employed by different Monte Carlo codes. (authors)

144

Multimodal neuroimaging based classification of autism spectrum disorder using anatomical, neurochemical, and white matter correlates.  

Science.gov (United States)

Neuroimaging techniques, such as fMRI, structural MRI, diffusion tensor imaging (DTI), and proton magnetic resonance spectroscopy (1H-MRS) have uncovered evidence for widespread functional and anatomical brain abnormalities in autism spectrum disorder (ASD) suggesting it to be a system-wide neural systems disorder. Nevertheless, most previous studies have focused on examining one index of neuropathology through a single neuroimaging modality, and seldom using multiple modalities to examine the same cohort of individuals. The current study aims to bring together multiple brain imaging modalities (structural MRI, DTI, and 1H-MRS) to investigate the neural architecture in the same set of individuals (19 high-functioning adults with ASD and 18 typically developing (TD) peers). Morphometry analysis revealed increased cortical thickness in ASD participants, relative to typical controls, across the left cingulate, left pars opercularis of the inferior frontal gyrus, left inferior temporal cortex, and right precuneus, and reduced cortical thickness in right cuneus and right precentral gyrus. ASD adults also had reduced fractional anisotropy (FA) and increased radial diffusivity (RD) for two clusters on the forceps minor of the corpus callosum, revealed by DTI analyses. 1H-MRS results showed a reduction in the N-acetylaspartate/Creatine ratio in dorsal anterior cingulate cortex (dACC) in ASD participants. A decision tree classification analysis across the three modalities resulted in classification accuracy of 91.9% with FA, RD, and cortical thickness as key predictors. Examining the same cohort of adults with ASD and their TD peers, this study found alterations in cortical thickness, white matter (WM) connectivity, and neurochemical concentration in ASD. These findings underscore the potential for multimodal imaging to better inform on the neural characteristics most relevant to the disorder. PMID:25797658

Libero, Lauren E; DeRamus, Thomas P; Lahti, Adrienne C; Deshpande, Gopikrishna; Kana, Rajesh K

2015-05-01

145

Power deposition in the head and neck of an anatomically based human body model for plane wave exposures  

International Nuclear Information System (INIS)

At certain frequencies, when the human head becomes a resonant structure, the power absorbed by the head and neck, when the body is exposed to a vertically polarized plane wave propagating from front to back, becomes significantly larger than would ordinarily be expected from its shadow cross section. This has possible implications in the study of the biological effects of electromagnetic fields. Additionally the frequencies at which these resonances occur are not readily predicted by simple approximations of the head in isolation. In order to determine these resonant conditions an anatomically based model of the whole human body has been used, with the finite-difference time-domain (FDTD) algorithm to accurately determine field propagation, specific absorption rate (SAR) distributions and power absorption in both the whole body and the head region (head and neck). This paper shows that resonant frequencies can be determined using two methods. The first is by use of the accurate anatomically based model (with heterogeneous tissue properties) and secondly using a model built from parallelepiped sections (for the torso and legs), an ellipsoid for the head and a cylinder for the neck. This approximation to the human body is built from homogeneous tissue the equivalent of two-thirds the conductivity and dielectric constant of that of muscle. An IBM SP-2 supercomputer together with a parallel FDTD code has been used to accommodate the large problem size. We find resonant fthe large problem size. We find resonant frequencies for the head and neck at 207 MHz and 193 MHz for the isolated and grounded conditions, with absorption cross sections that are respectively 3.27 and 2.62 times the shadow cross section. (author)

146

Wavelet-based resolution recovery using an anatomical prior provides quantitative recovery for human population phantom PET [11C]raclopride data  

Science.gov (United States)

The objective of this study was to evaluate a resolution recovery (RR) method using a variety of simulated human brain [11C]raclopride positron emission tomography (PET) images. Simulated datasets of 15 numerical human phantoms were processed by a wavelet-based RR method using an anatomical prior. The anatomical prior was in the form of a hybrid segmented atlas, which combined an atlas for anatomical labelling and a PET image for functional labelling of each anatomical structure. We applied RR to both 60 min static and dynamic PET images. Recovery was quantified in 84 regions, comparing the typical ‘true’ value for the simulation, as obtained in normal subjects, simulated and RR PET images. The radioactivity concentration in the white matter, striatum and other cortical regions was successfully recovered for the 60 min static image of all 15 human phantoms; the dependence of the solution on accurate anatomical information was demonstrated by the difficulty of the technique to retrieve the subthalamic nuclei due to mismatch between the two atlases used for data simulation and recovery. Structural and functional synergy for resolution recovery (SFS-RR) improved quantification in the caudate and putamen, the main regions of interest, from?-30.1% and?-26.2% to?-17.6% and?-15.1%, respectively, for the 60 min static image and from?-51.4% and?-38.3% to?-27.6% and?-20.3% for the binding potential (BPND) image, respectively. The proposed methodology proved effective in the RR of small structures from brain [11C]raclopride PET images. The improvement is consistent across the anatomical variability of a simulated population as long as accurate anatomical segmentations are provided.

Shidahara, M.; Tsoumpas, C.; McGinnity, C. J.; Kato, T.; Tamura, H.; Hammers, A.; Watabe, H.; Turkheimer, F. E.

2012-05-01

147

Wavelet-based resolution recovery using an anatomical prior provides quantitative recovery for human population phantom PET [11C]raclopride data  

International Nuclear Information System (INIS)

The objective of this study was to evaluate a resolution recovery (RR) method using a variety of simulated human brain [11C]raclopride positron emission tomography (PET) images. Simulated datasets of 15 numerical human phantoms were processed by a wavelet-based RR method using an anatomical prior. The anatomical prior was in the form of a hybrid segmented atlas, which combined an atlas for anatomical labelling and a PET image for functional labelling of each anatomical structure. We applied RR to both 60 min static and dynamic PET images. Recovery was quantified in 84 regions, comparing the typical ‘true’ value for the simulation, as obtained in normal subjects, simulated and RR PET images. The radioactivity concentration in the white matter, striatum and other cortical regions was successfully recovered for the 60 min static image of all 15 human phantoms; the dependence of the solution on accurate anatomical information was demonstrated by the difficulty of the technique to retrieve the subthalamic nuclei due to mismatch between the two atlases used for data simulation and recovery. Structural and functional synergy for resolution recovery (SFS-RR) improved quantification in the caudate and putamen, the main regions of interest, from??30.1% and??26.2% to??17.6% and??15.1%, respectively, for the 60 min static image and from??51.4% and??38.3% to??27.6% and??20.3% for the binding potential (BPND) image, respectispectively. The proposed methodology proved effective in the RR of small structures from brain [11C]raclopride PET images. The improvement is consistent across the anatomical variability of a simulated population as long as accurate anatomical segmentations are provided. (paper)

148

Quantification of accuracy of the automated nonlinear image matching and anatomical labeling (ANIMAL) nonlinear registration algorithm for 4D CT images of lung  

International Nuclear Information System (INIS)

The performance of the ANIMAL (Automated Nonlinear Image Matching and Anatomical Labeling) nonlinear registration algorithm for registration of thoracic 4D CT images was investigated. The algorithm was modified to minimize the incidence of deformation vector discontinuities that occur during the registration of lung images. Registrations were performed between the inhale and exhale phases for five patients. The registration accuracy was quantified by the cross-correlation of transformed and target images and distance to agreement (DTA) measured based on anatomical landmarks and triangulated surfaces constructed from manual contours. On average, the vector DTA between transformed and target landmarks was 1.6 mm. Comparing transformed and target 3D triangulated surfaces derived from planning contours, the average target volume (GTV) center-of-mass shift was 2.0 mm and the 3D DTA was 1.6 mm. An average DTA of 1.8 mm was obtained for all planning structures. All DTA metrics were comparable to inter observer uncertainties established for landmark identification and manual contouring

149

Methyl jasmonate and oxalic acid treatment of Norway spruce: anatomically based defense responses and increased resistance against fungal infection.  

Science.gov (United States)

To study the effect of chemical pretreatment on conifer resistance, 13-year-old Norway spruce (Picea abies (L.) Karst.) trees were treated with methyl jasmonate (MJ) or oxalic acid (OxA) on the outer bark and inoculated with the pathogenic blue-stain fungus Ceratocystis polonica (Siem.) C. Moreau 4 weeks later. Both chemicals significantly reduced symptoms of fungal infection, but MJ was more effective than OxA (51 versus 18% reduction in length of necrotic lesions in the phloem relative to untreated control trees). Anatomical examination of treated stem tissues showed that MJ induced extensive formation of traumatic resin ducts in the xylem and extra polyphenolic parenchyma (PP) cells in the secondary phloem between the cambium and the regular annual PP cell layer. No traumatic resin ducts were formed after treatment with OxA, and the coverage of extra PP cells in OxA-treated tissues was not significantly higher than in the controls. The anatomically based defense reactions induced by MJ were similar to the reactions observed after pathogen infection, mechanical wounding and bark beetle attack. Neither MJ nor OxA had apparent phytotoxic effects on Norway spruce at the concentrations used, with needle and stem tissues of all trees appearing normal without visible symptoms of toxicity. However, trees treated with MJ had 30% less radial sapwood growth than control trees. In conclusion, MJ treatment of Norway spruce appears to have practical potential as a tool for increasing plant resistance to fungal infection, but with a modest reduction in sapwood growth. PMID:17938111

Krokene, Paal; Nagy, Nina Elisabeth; Solheim, Halvor

2008-01-01

150

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.

151

Statistical 3D prostate imaging atlas construction via anatomically constrained registration  

Science.gov (United States)

Statistical imaging atlases allow for integration of information from multiple patient studies collected across different image scales and modalities, such as multi-parametric (MP) MRI and histology, providing population statistics regarding a specific pathology within a single canonical representation. Such atlases are particularly valuable in the identification and validation of meaningful imaging signatures for disease characterization in vivo within a population. Despite the high incidence of prostate cancer, an imaging atlas focused on different anatomic structures of the prostate, i.e. an anatomic atlas, has yet to be constructed. In this work we introduce a novel framework for MRI atlas construction that uses an iterative, anatomically constrained registration (AnCoR) scheme to enable the proper alignment of the prostate (Pr) and central gland (CG) boundaries. Our current implementation uses endorectal, 1.5T or 3T, T2-weighted MRI from 51 patients with biopsy confirmed cancer; however, the prostate atlas is seamlessly extensible to include additional MRI parameters. In our cohort, radical prostatectomy is performed following MP-MR image acquisition; thus ground truth annotations for prostate cancer are available from the histological specimens. Once mapped onto MP-MRI through elastic registration of histological slices to corresponding T2-w MRI slices, the annotations are utilized by the AnCoR framework to characterize the 3D statistical distribution of cancer per anatomic structure. Such distributions are useful for guiding biopsies toward regions of higher cancer likelihood and understanding imaging profiles for disease extent in vivo. We evaluate our approach via the Dice similarity coefficient (DSC) for different anatomic structures (delineated by expert radiologists): Pr, CG and peripheral zone (PZ). The AnCoR-based atlas had a CG DSC of 90.36%, and Pr DSC of 89.37%. Moreover, we evaluated the deviation of anatomic landmarks, the urethra and veromontanum, and found 3.64 mm and respectively 4.31 mm. Alternative strategies that use only the T2-w MRI or the prostate surface to drive the registration were implemented as comparative approaches. The AnCoR framework outperformed the alternative strategies by providing the lowest landmark deviations.

Rusu, Mirabela; Bloch, B. Nicolas; Jaffe, Carl C.; Rofsky, Neil M.; Genega, Elizabeth M.; Feleppa, Ernest; Lenkinski, Robert E.; Madabhushi, Anant

2013-03-01

152

Statistical 3D Prostate Imaging Atlas Construction via Anatomically Constrained Registration  

Science.gov (United States)

Statistical imaging atlases allow for integration of information from multiple patient studies collected across different image scales and modalities, such as multi-parametric (MP) MRI and histology, providing population statistics regarding a specific pathology within a single canonical representation. Such atlases are particularly valuable in the identification and validation of meaningful imaging signatures for disease characterization in vivo within a population. Despite the high incidence of prostate cancer, an imaging atlas focused on different anatomic structures of the prostate, i.e. an anatomic atlas, has yet to be constructed. In this work we introduce a novel framework for MRI atlas construction that uses an iterative, anatomically constrained registration (AnCoR) scheme to enable the proper alignment of the prostate (Pr) and central gland (CG) boundaries. Our current implementation uses endorectal, 1.5T or 3T, T2-weighted MRI from 51 patients with biopsy confirmed cancer; however, the prostate atlas is seamlessly extensible to include additional MRI parameters. In our cohort, radical prostatectomy is performed following MP-MR image acquisition; thus ground truth annotations for prostate cancer are available from the histological specimens. Once mapped onto MP-MRI through elastic registration of histological slices to corresponding T2-w MRI slices, the annotations are utilized by the AnCoR framework to characterize the 3D statistical distribution of cancer per anatomic structure. Such distributions are useful for guiding biopsies toward regions of higher cancer likelihood and understanding imaging profiles for disease extent in vivo. We evaluate our approach via the Dice similarity coefficient (DSC) for different anatomic structures (delineated by expert radiologists): Pr, CG and peripheral zone (PZ). The AnCoR-based atlas had a CG DSC of 90.36%, and Pr DSC of 89.37%. Moreover, we evaluated the deviation of anatomic landmarks, the urethra and veromontanum, and found 3.64 mm and respectively 4.31 mm. Alternative strategies that use only the T2-w MRI or the prostate surface to drive the registration were implemented as comparative approaches. The AnCoR framework outperformed the alternative strategies by providing the lowest landmark deviations. PMID:24392203

Rusu, Mirabela; Bloch, B. Nicolas; Jaffe, Carl C.; Rofsky, Neil M.; Genega, Elizabeth M.; Feleppa, Ernest; Lenkinski, Robert E.; Madabhushi, Anant

2013-01-01

153

Clinical correlates of the anatomical relationships of the foramen ovale: a radioanatomical study.  

Science.gov (United States)

Introduction Endonasal endoscopic transpterygoid approaches are commonly used techniques to access the infratemporal fossa and parapharyngeal space. Important endoscopic endonasal landmarks for the poststyloid parapharyngeal space, hence the internal carotid artery, include the mandibular nerve at the level of foramen ovale and the lateral pterygoid plate. This study aims to define the anatomical relationships of the foramen ovale, establishing its distance to other important anatomical landmarks such as the pterygoid process and columella. Methods Distances between the foramen ovale, foramen rotundum, and fixed anatomical landmarks like the columella and pterygoid process were measured using computed tomography (CT) scans and cadaveric dissections of the pterygopalatine and infratemporal fossae. Results The mean distances from the foramen ovale to columella and from the foramen rotundum to columella were found to be 9.15 cm and 7.09 cm, respectively. Analysis of radiologic measurements detected no statistically significant differences between sides or gender. Conclusions The pterygoid plates and V3 are prominent landmarks of the endonasal endoscopic approach to the infratemporal fossa and poststyloid parapharyngeal space. A better understanding of the endoscopic anatomy of the infratemporal fossa and awareness of the approximate distances and geometry among anatomical landmarks facilitates a safe and complete resection of lesions arising or extending to these regions. PMID:25452902

Youssef, Ahmed; Carrau, Ricardo L; Tantawy, Ahmed; Ibrahim, Ahmed Ali; Prevedello, Daniel M; Otto, Bradley A; Solares, Arturo C; Ditzel Filho, Leo F S; Rompaey, Jason

2014-12-01

154

The periodization of wheat embryogenesis on the base of anatomical, morphological and time criterions  

Directory of Open Access Journals (Sweden)

Full Text Available The periodization of wheat embryogenesis on the base of anatomy-morphological and temporal criterions has been proposed. The stages of non-differentiated embryo, embryo differentiation and differentiated embryo were described.

Natalia N. Kruglova

2013-04-01

155

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

Science.gov (United States)

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

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

1994-10-01

156

23 CFR 750.710 - Landmark signs.  

Science.gov (United States)

...HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RIGHT-OF-WAY AND ENVIRONMENT HIGHWAY BEAUTIFICATION Outdoor Advertising Control § 750.710 Landmark signs. (a) 23 U.S.C. 131(c) permits the existence of...

2010-04-01

157

75 FR 69120 - National Natural Landmark Designations  

Science.gov (United States)

...implications. National Natural Landmark preservation is made possible by the long- term...contains a rich fauna and significant paleontological deposits. The Chazy Fossil Reef is...Frost, Associate Director, Natural Resource Stewardship and Science....

2010-11-10

158

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)

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.

Jansen Casper L

2011-07-01

159

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.

160

Safe and successful bone marrow biopsy: an anatomical and CT-based cadaver study.  

Science.gov (United States)

Bone marrow biopsy is generally a safe procedure. However, infrequently the procedure is associated with serious injuries that are attributed to inadvertent needle penetration of the iliac bone's inner cortex. An evidence-based approach to needle orientation during iliac crest biopsy does not exist. In our study, the posterior to anterior path of the bone marrow needle from the posterior superior iliac spine (PSIS) was studied in human cadavers in two orientations: (1) perpendicularly to the coronal plane (the perpendicular approach) and (2) laterally toward the ipsilateral anterior superior iliac spine (ASIS) (the lateral approach). The biopsy needle was deliberately advanced through the inner ilial cortex in both approaches. Dissections and imaging studies were done to identify the relationship of the penetrating needle to internal structures. Both approaches begin with a perpendicular puncture of the outer cortex at the PSIS. The perpendicular approach proceeds anteriorly whereas in the lateral approach the needle is reoriented toward the ipsilateral ASIS before advancing. The lateral approach caused less damage to neurovascular structures and avoided the sacroiliac joint compared to the perpendicular approach. This procedure is best done in the lateral decubitus position. Proper use of the lateral approach should obviate many of the complications reported in the literature. PMID:24942104

Konda, Bhavana; Pathak, Swati; Edwin, Inga; Mishall, Priti; Downie, Sherry A; Olson, Todd R; Reed, Louis J; Friedman, Ellen W

2014-10-01

161

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

Science.gov (United States)

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

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

162

Design Guidelines for Landmarks to Support Navigation in Virtual Environments  

OpenAIRE

Unfamiliar, large-scale virtual environments are difficult to navigate. This paper presents design guidelines to ease navigation in such virtual environments. The guidelines presented here focus on the design and placement of landmarks in virtual environments. Moreover, the guidelines are based primarily on the extensive empirical literature on navigation in the real world. A rationale for this approach is provided by the similarities between navigational behavior in real an...

Vinson, Norman G.

2003-01-01

163

Associative Basis of Landmark Learning and Integration in Vertebrates  

OpenAIRE

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, ...

Leising, Kenneth J.; Blaisdell, Aaron P.

2009-01-01

164

The fifth metatarsal base: anatomic evaluation regarding fracture mechanism and treatment algorithms.  

Science.gov (United States)

Fractures occurring within the 1.5-cm proximal portion of the fifth metatarsal are commonly considered avulsion fractures. The exact mechanisms of such fractures are controversial. The present study focused on determining the likely mechanism of fracture according to the exact anatomy to allow for more successful treatment. The research sample included 10 frozen cadaveric specimens. The lateral band of the plantar fascia, peroneus brevis, and articular surface were identified and separated from their attachments, thereby splitting the fifth metatarsal base into zones A, B, and C. In zone A, the attachment of the plantar fascia was 6.6 ± 2.2 mm from the inferior aspect, 9.5 ± 2.9 mm from the proximal aspect, and 11.5 ± 0.9 mm from the lateral aspect. In zone B, the attachment of the peroneus brevis was 12.0 ± 2.2 mm from the inferior aspect, 10.2 ± 2.2 mm from the proximal aspect, and 11.5 ± 0.9 mm from the lateral aspect. Zone C was measured from the border of zone B and encompassed the articulation of the fifth metatarsal to the cuboid. We propose that fractures occurring in the most proximal end of the fifth metatarsal, zone A, are caused by a lateral band of plantar fascia and might be able to be treated conservatively by immobilization with weightbearing. We also propose that fractures occurring in zones B and C result from traumatic tension on peroneus brevis and might need to be treated with strict immobilization and non-weightbearing or open reduction internal fixation. PMID:25441854

DeVries, J George; Taefi, Erfan; Bussewitz, Bradly W; Hyer, Christopher F; Lee, Thomas H

2015-01-01

165

Island adipofascial flap based on distal perforators of the radial artery: an anatomic and clinical investigation.  

Science.gov (United States)

Reconstruction of soft-tissue defects of the hand with exposed tendons, joints, and bone represents a challenge to the plastic surgeon, and such defects necessitate flap coverage to preserve hand function and to protect its vital structures. Reported here is the study of an island adipofascial flap based solely on the distal five to eight septocutaneous perforators of the radial artery and their venae comitantes. Designing the flap in the form of an island with skeletonization of the distal perforators of the radial artery ensures its vascular pattern from these perforators alone with no connection to the ulnar artery perforators or posterior interosseous artery perforators, as is the case with fascial pedicled flaps. Furthermore, designing the flap as an island facilitates the arc of rotation and avoids the pedicle kink when the flap is turned 180 degrees. Preservation of the radial artery, as well as the mild thickness of the flap are further advantages. The drawbacks of such a flap include temporary impaired sensation at the donor site, the obvious scar in the forearm, and loss of hair. Eleven fresh and fixed cadaver upper extremities were dissected to delineate the vascular pattern and to define the arc of rotation of the flap. Also, a clinical approach was conducted on two patients who sustained extension scar contracture with tendon adhesions of the dorsum of the hands, on two patients who sustained first web space contracture, and on two patients who had full-thickness soft-tissue loss over the palm; and finally on two patients who sustained traumatic soft-tissue loss over the dorsum of their hands with exposed tendons and metacarpal bones. PMID:9393473

el-Khatib, H; Zeidan, M

1997-12-01

166

Quality-Aware Estimation of Facial Landmarks in Video Sequences  

DEFF Research Database (Denmark)

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).

Haque, Mohammad Ahsanul; Nasrollahi, Kamal

2015-01-01

167

Ageing effects on path integration and landmark navigation.  

Science.gov (United States)

Navigation abilities show marked decline in both normal ageing and dementia. Path integration may be particularly affected, as it is supported by the hippocampus and entorhinal cortex, both of which show severe degeneration with ageing. Age differences in path integration based on kinaesthetic and vestibular cues have been clearly demonstrated, but very little research has focused on visual path integration, based only on optic flow. Path integration is complemented by landmark navigation, which may also show age differences, but has not been well studied either. Here we present a study using several simple virtual navigation tasks to explore age differences in path integration both with and without landmark information. We report that, within a virtual environment that provided only optic flow information, older participants exhibited deficits in path integration in terms of distance reproduction, rotation reproduction, and triangle completion. We also report age differences in triangle completion within an environment that provided landmark information. In all tasks, we observed a more restricted range of responses in the older participants, which we discuss in terms of a leaky integrator model, as older participants showed greater leak than younger participants. Our findings begin to explain the mechanisms underlying age differences in path integration, and thus contribute to an understanding of the substantial decline in navigation abilities observed in ageing. PMID:22431367

Harris, Mathew A; Wolbers, Thomas

2012-08-01

168

Large-scale 3-D geometric reconstruction of the porcine coronary arterial vasculature based on detailed anatomical data.  

Science.gov (United States)

The temporal and spatial distribution of coronary blood flow, pressure, and volume are determined by the branching pattern and three-dimensional (3-D) geometry of the coronary vasculature, and by the mechanics of heart wall and vascular tone. Consequently, a realistic simulation of coronary blood flow requires, as a first step, an accurate representation of the coronary vasculature in a 3-D model of the beating heart. In the present study, a large-scale stochastic reconstruction of the asymmetric coronary arterial trees (right coronary artery, RCA; left anterior descending, LAD; and left circumflex, LCx) of the porcine heart has been carried out to set the stage for future hemodynamic analysis. The model spans the entire coronary arterial tree down to the capillary vessels. The 3-D tree structure was reconstructed initially in rectangular slab geometry by means of global geometrical optimization using parallel simulated annealing (SA) algorithm. The SA optimization was subject to constraints prescribed by previously measured morphometric features of the coronary arterial trees. Subsequently, the reconstructed trees were mapped onto a prolate spheroid geometry of the heart. The transformed geometry was determined through least squares minimization of the related changes in both segments lengths and their angular characteristics. Vessel diameters were assigned based on a novel representation of diameter asymmetry along bifurcations. The reconstructed RCA, LAD and LCx arterial trees show qualitative resemblance to native coronary networks, and their morphological statistics are consistent with the measured data. The present model constitutes the first most extensive reconstruction of the entire coronary arterial system which will serve as a geometric foundation for future studies of flow in an anatomically accurate 3-D coronary vascular model. PMID:16341920

Kaimovitz, Benjamin; Lanir, Yoram; Kassab, Ghassan S

2005-11-01

169

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: ... you'll be able to watch a live global AP anatomic total shoulder surgery from Methodist Hospital ...

170

Perceptual organization and artificial attention for visual landmarks detection.  

Science.gov (United States)

In biological vision systems, attention mechanisms are responsible for selecting the relevant information from the sensed field of view, so that the complete scene can be analyzed using a sequence of rapid eye saccades. In recent years, efforts have been made to imitate such attention behavior in artificial vision systems, because it allows optimizing the computational resources as they can be focused on the processing of a set of selected regions. In the framework of mobile robotics navigation, this work proposes an artificial model where attention is deployed at the level of objects (visual landmarks) and where new processes for estimating bottom-up and top-down (target-based) saliency maps are employed. Bottom-up attention is implemented through a hierarchical process, whose final result is the perceptual grouping of the image content. The hierarchical grouping is applied using a Combinatorial Pyramid that represents each level of the hierarchy by a combinatorial map. The process takes into account both image regions (faces in the map) and edges (arcs in the map). Top-down attention searches for previously detected landmarks, enabling their re-detection when the robot presumes that it is revisiting a known location. Landmarks are described by a combinatorial submap; thus, this search is conducted through an error-tolerant submap isomorphism procedure. PMID:23328946

Antúnez, Esther; Palomino, Antonio J; Marfil, Rebeca; Bandera, Juan P

2013-03-01

171

Locating landmarks on high-dimensional free energy surfaces.  

Science.gov (United States)

Coarse graining of complex systems possessing many degrees of freedom can often be a useful approach for analyzing and understanding key features of these systems in terms of just a few variables. The relevant energy landscape in a coarse-grained description is the free energy surface as a function of the coarse-grained variables, which, despite the dimensional reduction, can still be an object of high dimension. Consequently, navigating and exploring this high-dimensional free energy surface is a nontrivial task. In this paper, we use techniques from multiscale modeling, stochastic optimization, and machine learning to devise a strategy for locating minima and saddle points (termed "landmarks") on a high-dimensional free energy surface "on the fly" and without requiring prior knowledge of or an explicit form for the surface. In addition, we propose a compact graph representation of the landmarks and connections between them, and we show that the graph nodes can be subsequently analyzed and clustered based on key attributes that elucidate important properties of the system. Finally, we show that knowledge of landmark locations allows for the efficient determination of their relative free energies via enhanced sampling techniques. PMID:25737545

Chen, Ming; Yu, Tang-Qing; Tuckerman, Mark E

2015-03-17

172

Sparse decomposition and modeling of anatomical shape variation  

DEFF Research Database (Denmark)

Recent advances in statistics have spawned powerful methods for regression and data decomposition that promote sparsity, a property that facilitates interpretation of the results. Sparse models use a small subset of the available variables and may perform as well or better than their full counterparts if constructed carefully. In most medical applications, models are required to have both good statistical performance and a relevant clinical interpretation to be of value. Morphometry of the corpus callosum is one illustrative example. This paper presents a method for relating spatial features to clinical outcome data. A set of parsimonious variables is extracted using sparse principal component analysis, producing simple yet characteristic features. The relation of these variables with clinical data is then established using a regression model. The result may be visualized as patterns of anatomical variation related to clinical outcome. In the present application, landmark-based shape data of the corpus callosum is analyzed in relation to age, gender, and clinical tests of walking speed and verbal fluency. To put the data-driven sparse principal component method into perspective, we consider two alternative techniques, one where features are derived using a model-based wavelet approach, and one where the original variables are regressed directly on the outcome.

Sjöstrand, Karl; Rostrup, Egill

2007-01-01

173

Sparse Decomposition and Modeling of Anatomical Shape Variation  

DEFF Research Database (Denmark)

Recent advances in statistics have spawned powerful methods for regression and data decomposition that promote sparsity, a property that facilitates interpretation of the results. Sparse models use a small subset of the available variables and may perform as well or better than their full counterparts if constructed carefully. In most medical applications, models are required to have both good statistical performance and a relevant clinical interpretation to be of value. Morphometry of the corpus callosum is one illustrative example. This paper presents a method for relating spatial features to clinical outcome data. A set of parsimonious variables is extracted using sparse principal component analysis, producing simple yet characteristic features. The relation of these variables with clinical data is then established using a regression model. The result may be visualized as patterns of anatomical variation related to clinical outcome. In the present application, landmark-based shape data of the corpus callosum is analyzed in relation to age, gender, and clinical tests of walking speed and verbal fluency. To put the data-driven sparse principal component method into perspective, we consider two alternative techniques, one where features are derived using a model-based wavelet approach, and one where the original variables are regressed directly on the outcome.

Sjöstrand, Karl; Rostrup, Egill

2007-01-01

174

An Image-Based Model of the Whole Human Heart with Detailed Anatomical Structure and Fiber Orientation  

OpenAIRE

Many heart anatomy models have been developed to study the electrophysiological properties of the human heart. However, none of them includes the geometry of the whole human heart. In this study, an anatomically detailed mathematical model of the human heart was firstly reconstructed from the computed tomography images. In the reconstructed model, the atria consisted of atrial muscles, sinoatrial node, crista terminalis, pectinate muscles, Bachmann's bundle, intercaval bundles, and limbus of ...

Deng, Dongdong; Jiao, Peifeng; Ye, Xuesong; Xia, Ling

2012-01-01

175

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  

Directory of Open Access Journals (Sweden)

Full Text Available 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, Meram 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.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.

Aynur Emine Cicekcibasi

2012-06-01

176

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)

Full Text Available SciELO Chile | Language: English Abstract in spanish 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.

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

2012-06-01

177

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

OpenAIRE

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 requi...

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

2003-01-01

178

Beyond cortical localization in clinico-anatomical correlation.  

Science.gov (United States)

Last year was the 150th anniversary of Paul Broca's landmark case report on speech disorder that paved the way for subsequent studies of cortical localization of higher cognitive functions. However, many complex functions rely on the activity of distributed networks rather than single cortical areas. Hence, it is important to understand how brain regions are linked within large-scale networks and to map lesions onto connecting white matter tracts. To facilitate this network approach we provide a synopsis of classical neurological syndromes associated with frontal, parietal, occipital, temporal and limbic lesions. A review of tractography studies in a variety of neuropsychiatric disorders is also included. The synopsis is accompanied by a new atlas of the human white matter connections based on diffusion tensor tractography freely downloadable on http://www.natbrainlab.com. Clinicians can use the maps to accurately identify the tract affected by lesions visible on conventional CT or MRI. The atlas will also assist researchers to interpret their group analysis results. We hope that the synopsis and the atlas by allowing a precise localization of white matter lesions and associated symptoms will facilitate future work on the functional correlates of human neural networks as derived from the study of clinical populations. Our goal is to stimulate clinicians to develop a critical approach to clinico-anatomical correlative studies and broaden their view of clinical anatomy beyond the cortical surface in order to encompass the dysfunction related to connecting pathways. PMID:22995574

Catani, Marco; Dell'acqua, Flavio; Bizzi, Alberto; Forkel, Stephanie J; Williams, Steve C; Simmons, Andrew; Murphy, Declan G; Thiebaut de Schotten, Michel

2012-01-01

179

Automated landmark-guided deformable image registration  

Science.gov (United States)

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.

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

2015-01-01

180

VISITO Tuscany: landmark recognition for cultural heritage  

OpenAIRE

VISITO Tuscany (VIsual Support to Interactive TOurism in Tuscany) is a research project which investigates techniques for producing an interactive guide, accessible via smartphone, for tourists visiting cities of art. The system applies image analysis and content recognition techniques to recognize photographed monuments. The user just has to take a picture of a tourist landmark to obtain pertinent information on his or her smartphone.

Amato, Giuseppe; Falchi, Fabrizio; Bolettieri, Paolo

2011-01-01

181

Landmark papers on photorefractive nonlinear optics  

CERN Document Server

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.

Yeh, Pochi

1995-01-01

182

Assessment of landmark measurements of craniofacial images from 2D and 3D reconstructions of spiral CT  

Science.gov (United States)

Purpose: The purpose of this study is to compare the accuracy of facial linear measurements obtained from volumetric spiral CT using 2D versus 3D reconstruction, and test the repeatability of these measurements. Material and Methods: The population consisted of 5 cadaver heads that were scanned to a Spiral CT scanner (120 Kvp and 200 mA, Toshiba Xpress S/X Toshiba-America, Medical System Inc., Tustin, CA) with high- resolution contiguous slices. Heads were scanned with 3 mm thick axial slices and a 2 mm/sec table feed. The CT data were archived on optical disks, and then transferred to a networked computer workstation (Sun Microsystems with Cemax version 1.4 software, Fremont, CA), to generate 2D and 3D images for manipulation and analyses. Repeated measurements were done on 2D and 3D images reconstructed from spiral CT scans on the workstation. Linear measurements were done by 2 observers with 2 sessions each, using several unique and conventional craniometric anatomic landmarks. The soft tissues were then partially removed and physical measurements of the same landmarks were repeated by an electromagnetic (3 space) digitizer (Polhemus Navigation Sciences Division, Mc Donnell Douglas Electronic Company, Colchester, VE). Analyses of variance were done to compare 2D versus 3D methods, and the accuracy of measurements between both imaging techniques. Results: The results showed statistically significant differences between 2D and 3D images for the majority of measurements. The 3D image measurements were not statistically different from the physical measurements. However, some of the 2D image landmarks differed from physical measurements. The repeatability of measurements was high by spiral CT-based craniofacial imaging. Conclusion: New computer graphics technology combined with 3D volumetric imaging by spiral CT can distinguish the craniofacial anatomy with greater accuracy than previously reported measurements and with greater accuracy than measurements from 2DCT images. These 3D measurements are essential to diagnostic and treatment planning of craniofacial injuries, anomalies and for craniofacial identification.

Cavalcanti, Marcelo G.; Haller, John W.; Vannier, Michael W.

1998-06-01

183

A landmark analysis-based approach to age and sex classification of the skull of the Mediterranean monk seal (Monachus monachus) (Hermann, 1779).  

Science.gov (United States)

This work aimed at applying geometric morphometric analysis techniques to the skull of the Mediterranean monk seal (Monachus monachus, Hermann, 1779). Inferential analyses were performed using a non-parameteric permutation framework based on a series of skulls of different age classes belonging to individuals of both sexes. Our goal was to establish whether a statistical approach based on osteometric measurements and surface analysis of photographs of the left lateral plane of the skull may lead to a different and scientifically sound method of age and sex classification in this critically endangered marine mammal. Our data indicate that non-parametric combination methodology enables the researcher to give local assessment using a combination with domains. Developing geometric morphometric techniques in a non-parametric permutation framework could be useful in solving high dimensional and small sample size problems as well as classification problems, including zoological classification of specimens within a specific population. The Mediterranean monk seal is believed to be the world's rarest pinniped and one of the most endangered mammals of the world, with fewer than 600 individuals currently surviving. The use of shape analysis would allow new insights into the biological characteristics of the monk seal by simply extracting potentially new information on age and size from museal specimens. PMID:19694647

Brombin, C; Mo, G; Zotti, A; Giurisato, M; Salmaso, L; Cozzi, B

2009-10-01

184

Strategies in Landmark Use by Children, Adults, and Marmoset Monkeys  

Science.gov (United States)

Common marmosets ("Callithrix jacchus jacchus"), human children, and human adults learned to find a goal that was located in the center of a square array of four identical landmarks. The location of the landmark array and corresponding goal varied across trials, so the task could not be solved without using the landmark array. In Experiment 1, a…

MacDonald, Suzanne E.; Spetch, Marcia L.; Kelly, Debbie M.; Cheng, Ken

2004-01-01

185

Fluence-to-dose conversion coefficients from monoenergetic neutrons below 20 MeV based on the VIP-Man anatomical model  

International Nuclear Information System (INIS)

A new set of fluence-to-absorbed dose and fluence-to-effective dose conversion coefficients have been calculated for neutrons below 20 MeV using a whole-body anatomical model, VIP-Man, developed from the high-resolution transverse colour photographic images of the National Library of Medicine's Visible Human Project. Organ dose calculations were performed using the Monte Carlo code MCNP for 20 monoenergetic neutron beams between 1x10-9 MeV and 20 MeV under six different irradiation geometries: anterior-posterior, posterior-anterior, right lateral, left lateral, rotational and isotropic. The absorbed dose for 24 major organs and effective dose results based on the realistic VIP-Man are presented and compared with those based on the simplified MIRD-based phantoms reported in the literature. Effective doses from VIP-Man are not significantly different from earlier results for neutrons in the energy range studied. There are, however, remarkable deviations in organ doses due to the anatomical differences between the image-based and the earlier mathematical models. (author)

186

Anatomical based reconstruction of dynamic brain PET images using N-[11C]-methylpiperidin-4-YL-proprionate ([11C]-PMP) in elderly normals  

OpenAIRE

Background and aims: Recently, we have developed a new PET reconstruction algorithm (AMAP) based on a maximum a-posteriori algorithm and using anatomical a-priori information obtained from MRI (Baete et al. 2004a,b). This algorithm corrects for partial volume effects during the reconstruction. The aim of this study was to study the effect on the modelling parameters when using data reconstructed with this new algorithm. Methods: In 10 healthy subjects (6 male, mean age: 67 yr), data were acqu...

Nelissen, N.; Baete, K.; Vandenbulcke, M.; Bormans, G.; Nuyts, J.; Kinnard, V.; Groot, T.; Laere, K.; Vandenberghe, R.; Dupont, P.

2007-01-01

187

Description of two new Ecuadorian Zilchistrophia Weyrauch, 1960, with the clarification of the systematic position of the genus based on anatomical data (Gastropoda, Stylommatophora, Scolodontidae)  

Science.gov (United States)

Abstract Two new species of the genus Zilchistrophia Weyrauch, 1960 are described from Eastern Ecuadorian rain forest: Zilchistrophia hilaryae sp. n. and Zilchistrophia shiwiarorum sp. n. These two new species extend the distribution of the genus considerably northwards, because congeners have been reported from Peru only. For the first time we present anatomical data (radula, buccal mass, morphology of the foot and the genital structure) of Zilchistrophia species. According to these, the genus belongs to the family Scolodontidae, subfamily Scolodontinae (=“Systrophiini”). The previously assumed systematic relationship of Zilchistrophia with the Asian Corillidae and Plectopylidae based on the similarly looking palatal plicae is not supported. PMID:25493057

Páll-Gergely, Barna; Asami, Takahiro

2014-01-01

188

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

OpenAIRE

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...

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

189

An image-based model of the whole human heart with detailed anatomical structure and fiber orientation.  

Science.gov (United States)

Many heart anatomy models have been developed to study the electrophysiological properties of the human heart. However, none of them includes the geometry of the whole human heart. In this study, an anatomically detailed mathematical model of the human heart was firstly reconstructed from the computed tomography images. In the reconstructed model, the atria consisted of atrial muscles, sinoatrial node, crista terminalis, pectinate muscles, Bachmann's bundle, intercaval bundles, and limbus of the fossa ovalis. The atrioventricular junction included the atrioventricular node and atrioventricular ring, and the ventricles had ventricular muscles, His bundle, bundle branches, and Purkinje network. The epicardial and endocardial myofiber orientations of the ventricles and one layer of atrial myofiber orientation were then measured. They were calculated using linear interpolation technique and minimum distance algorithm, respectively. To the best of our knowledge, this is the first anatomically-detailed human heart model with corresponding experimentally measured fibers orientation. In addition, the whole heart excitation propagation was simulated using a monodomain model. The simulated normal activation sequence agreed well with the published experimental findings. PMID:22952559

Deng, Dongdong; Jiao, Peifeng; Ye, Xuesong; Xia, Ling

2012-01-01

190

Algorithms to automatically quantify the geometric similarity of anatomical surfaces  

CERN Document Server

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...

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

2011-01-01

191

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)

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

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

2014-09-01

192

The orbits--anatomical features in view of innovative surgical methods.  

Science.gov (United States)

The aim of this article is to update on anatomical key elements of the orbits in reference to surgical innovations. This is a selective literature review supplemented with the personal experience of the authors, using illustrations and photographs of anatomical dissections. The seven osseous components of the orbit can be conceptualized into a simple geometrical layout of a four-sided pyramid with the anterior aditus as a base and the posterior cone as apex. All neurovascular structures pass through bony openings in the sphenoid bone before diversification in the mid and anterior orbit. A set of landmarks such as the optic and maxillary strut comes into new focus. Within the topographical surfaces of the internal orbit the lazy S-shaped floor and the posteromedial bulge are principal determinants for the ocular globe position. The inferomedial orbital strut represents a discernible sagittal buttress. The periorbita and orbital soft tissue contents--extraocular muscles, septae, neurovasculature--are detailed and put into context with periorbital dissection. PMID:25397705

Cornelius, Carl-Peter; Mayer, Peter; Ehrenfeld, Michael; Metzger, Marc Christian

2014-10-01

193

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 depenhe 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

194

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

Science.gov (United States)

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 500 x 500 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 (448 x 448 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 7 x 7 regions of interest (ROIs: 64 x 64 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 (128 x 128 matrix size), each having its central part (64 x 64 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. PMID:16898468

Shiraishi, Junji; Li, Qiang; Suzuki, Kenji; Engelmann, Roger; Doi, Kunio

2006-07-01

195

The behavioural relevance of landmark texture for honeybee homing  

Directory of Open Access Journals (Sweden)

Full Text Available Honeybees visually pinpoint the location of a food source using landmarks. Studies on the role of visual memories have suggested that bees approach the goal by finding a close match between their current view and a memorized view of the goal location. The most relevant landmark features for this matching process seem to be their retinal positions, the size as defined by their edges, and their colour. Recently, we showed that honeybees can use landmarks that are statically camouflaged, suggesting that motion cues are relevant as well. Currently it is unclear how bees weight these different landmark features when accomplishing navigational tasks, and whether this depends on their saliency. Since natural objects are often distinguished by their texture, we investigate the behavioural relevance and the interplay of the spatial configuration and the texture of landmarks. We show that landmark texture is a feature that bees memorise, and being given the opportunity to identify landmarks by their texture improves the bees’ navigational performance. Landmark texture is weighted more strongly than landmark configuration when it provides the bees with positional information and when the texture is salient. In the vicinity of the landmark honeybees changed their flight behaviour according to its texture.

LauraDittmar

2011-04-01

196

Development of a patient-specific anatomical foot model from structured light scan data.  

Science.gov (United States)

The use of anatomically accurate finite element (FE) models of the human foot in research studies has increased rapidly in recent years. Uses for FE foot models include advancing knowledge of orthotic design, shoe design, ankle-foot orthoses, pathomechanics, locomotion, plantar pressure, tissue mechanics, plantar fasciitis, joint stress and surgical interventions. Similar applications but for clinical use on a per-patient basis would also be on the rise if it were not for the high costs associated with developing patient-specific anatomical foot models. High costs arise primarily from the expense and challenges of acquiring anatomical data via magnetic resonance imaging (MRI) or computed tomography (CT) and reconstructing the three-dimensional models. The proposed solution morphs detailed anatomy from skin surface geometry and anatomical landmarks of a generic foot model (developed from CT or MRI) to surface geometry and anatomical landmarks acquired from an inexpensive structured light scan of a foot. The method yields a patient-specific anatomical foot model at a fraction of the cost of standard methods. Average error for bone surfaces was 2.53 mm for the six experiments completed. Highest accuracy occurred in the mid-foot and lowest in the forefoot due to the small, irregular bones of the toes. The method must be validated in the intended application to determine if the resulting errors are acceptable. PMID:23181631

Lochner, Samuel J; Huissoon, Jan P; Bedi, Sanjeev S

2014-01-01

197

[Anatomical and radiological aspects in lumbopelvic fixation].  

Science.gov (United States)

Spinal and pelvic surgery (as in neuromuscular scoliosis or unilateral highly unstable vertical sacral fractures or unstable H- or U-shaped sacral fractures) relies on lumbopelvic fixation. This technique belongs to the standard procedures for lumbosacral injuries in orthopedic surgery. Preoperatively, a CT scan with 1 mm slices is essential to detect anatomical variants and cortical narrow nesses. For optimal insertion of pedicel screws, knowledge of the pedicle diameter and length is necessary and screws should be placed convergent to each other taking into consideration the pedicle length and angle. For placement of the iliac screws exact knowledge of the anatomy is essential to avoid cortical wall perforation and neurovascular injuries. The safest screw path was determined as the bony canal between the posterior superior iliac spine (PSIS) and the anterior inferior iliac spine (AIIS). Intraoperatively, standard fluoroscopic views allow safe placement of the screws. The aim of the following manuscript is to illustrate anatomical and morphological aspects of the spine and pelvis as well as to describe important bony landmarks and optimal intraoperative C-arm views for optimal screw insertion. PMID:24233082

Gothner, M; Dudda, M; Schildhauer, T A

2013-11-01

198

Placement of pedicle screws using three-dimensional fluoroscopy-based navigation in lumbar vertebrae with axial rotation  

OpenAIRE

Despite potential advantages of three-dimensional fluoroscopy-based navigation, there still remain a lot of controversies about the indications of this technology, especially whether it is worthy of being used in placement of pedicle screws in lumbar spine. However, according to the inconsistent conclusions reported in the literature and our experiences, the traditional method relying on anatomical landmarks and fluoroscopic views to guide lumbar pedicle screw insertion is unable to meet the ...

Tian, Wei; Lang, Zhao

2010-01-01

199

Anatomic Total Shoulder System  

Medline Plus

Full Text Available ... variability which allows adaptability to a patient's unique anatomical makeup. Dr. Gerald R. Williams, Jr., a shoulder ... pieces in in the appropriate orientation with good technique, you've got an 87% chance of it ...

200

Anatomic Total Shoulder System  

Medline Plus

Full Text Available ... the idea is to expose anatomic neck. 00:16:59 N. DOUGLAS BOARDMAN III, MD: Do you ... one of the more difficult things. 00:23:16 N. DOUGLAS BOARDMAN III, MD: Jerry, while we ...

201

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: ... to get rid of the excess cement and air above this particular portion. The tip of this ...

202

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. ...

203

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 care. In a few ...

204

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: ... working on this, what would you say the key to the glenoid exposure is for folks who ...

205

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 ...

206

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 ...

207

Anatomic variants of the hepatic arteries  

International Nuclear Information System (INIS)

The anatomic variants of the hepatic arteries observed in 216 abdominal arteriographies were analysed. A comparison was made with Michels' work based upon 200 anatomic dissections, and Suzuki's investigation of 200 abdominal arteriographies. Seven not previously classified anatomic variants of the hepatic arteries were found. The large number of variants may be ascribed to intricacies in the development of the vascular supply in the embryo and to the normal caudal displacement of the liver taking place in the embryo and fetus. Knowledge concerning existing variants is important in performing surgery, embolization and intra-arterial infusion chemotherapy in the hepatic region. (orig.)

208

Robust Mobile Robot Localization by Tracking Natural Landmarks  

Science.gov (United States)

This article presents a feature-based localization framework to use with conventional 2D laser rangefinder. The system is based on the Unscented Kalman Filter (UKF) approach, which can reduce the errors in the calculation of the robot's position and orientation. The framework consists of two main parts: feature extraction and multi-sensor fusing localization. The novelty of this system is that a new segmentation algorithm based-on the micro-tangent line (MTL) is introduced. Features, such as lines, corners and curves, can be characterized from the segments. For each landmark, the geometrical parameters are provided with statistical information, which are used in the subsequent matching phase, together with a priori map, so as to get an optimal estimate of the robot pose. Experimental results show that the proposed localization method is efficient in office-like environment.

Feng, Xiaowei; Guo, Shuai; Li, Xianhua; He, Yongyi

209

Assessment of Landmark Visibility for Automated Wayfinding Route Instructions  

OpenAIRE

Landmarks are used by people in unfamiliar spatial environments as points of reference with which to construct a mental comprehension of space. Supplementing route directions with landmark knowledge therefore improves cognitive ergonomics by increasing people’s ability to use, remember and communicate routes. This research addresses the problem of incorporating landmark knowledge into automatically generated route instructions by exploring the full lifecycle of application development. Two ...

Frankland, David

2010-01-01

210

Segmentation of brain magnetic resonance images based on multi-atlas likelihood fusion: testing using data with a broad range of anatomical and photometric profiles.  

Science.gov (United States)

We propose a hierarchical pipeline for skull-stripping and segmentation of anatomical structures of interest from T1-weighted images of the human brain. The pipeline is constructed based on a two-level Bayesian parameter estimation algorithm called multi-atlas likelihood fusion (MALF). In MALF, estimation of the parameter of interest is performed via maximum a posteriori estimation using the expectation-maximization (EM) algorithm. The likelihoods of multiple atlases are fused in the E-step while the optimal estimator, a single maximizer of the fused likelihoods, is then obtained in the M-step. There are two stages in the proposed pipeline; first the input T1-weighted image is automatically skull-stripped via a fast MALF, then internal brain structures of interest are automatically extracted using a regular MALF. We assess the performance of each of the two modules in the pipeline based on two sets of images with markedly different anatomical and photometric contrasts; 3T MPRAGE scans of pediatric subjects with developmental disorders vs. 1.5T SPGR scans of elderly subjects with dementia. Evaluation is performed quantitatively using the Dice overlap as well as qualitatively via visual inspections. As a result, we demonstrate subject-level differences in the performance of the proposed pipeline, which may be accounted for by age, diagnosis, or the imaging parameters (particularly the field strength). For the subcortical and ventricular structures of the two datasets, the hierarchical pipeline is capable of producing automated segmentations with Dice overlaps ranging from 0.8 to 0.964 when compared with the gold standard. Comparisons with other representative segmentation algorithms are presented, relative to which the proposed hierarchical pipeline demonstrates comparative or superior accuracy. PMID:25784852

Tang, Xiaoying; Crocetti, Deana; Kutten, Kwame; Ceritoglu, Can; Albert, Marilyn S; Mori, Susumu; Mostofsky, Stewart H; Miller, Michael I

2015-01-01

211

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

Science.gov (United States)

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…

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

2014-01-01

212

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

Directory of Open Access Journals (Sweden)

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.

Martin Egelhaaf

2014-09-01

213

The more, the better: the use of multiple landmark configurations to solve the phylogenetic relationships in musteloids.  

Science.gov (United States)

Although the use of landmark data to study shape changes along a phylogenetic tree has become a common practice in evolutionary studies, the role of this sort of data for the inference of phylogenetic relationships remains under debate. Theoretical issues aside, the very existence of historical information in landmark data has been challenged, since phylogenetic analyses have often shown little congruence with alternative sources of evidence. However, most analyses conducted in the past were based upon a single landmark configuration, leaving it unsettled whether the incorporation of multiple configurations may improve the rather poor performance of this data source in most previous phylogenetic analyses. In the present study, we present a phylogenetic analysis of landmark data that combines information derived from several skeletal structures to derive a phylogenetic tree for musteloids. The analysis includes nine configurations representing different skeletal structures for 24 species. The resulting tree presents several notable concordances with phylogenetic hypotheses derived from molecular data. In particular, Mephitidae, Procyonidae, and Lutrinae plus the genera Martes, Mustela, Galictis, and Procyon were retrieved as monophyletic. In addition, other groupings were in agreement with molecular phylogenies or presented only minor discordances. Complementary analyses have also indicated that the results improve substantially when an increasing number of landmark configurations are included in the analysis. The results presented here thus highlight the importance of combining information from multiple structures to derive phylogenetic hypotheses from landmark data. PMID:25516268

Catalano, Santiago A; Ercoli, Marcos D; Prevosti, Francisco J

2015-03-01

214

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 abductPF, 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.)

215

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

International Nuclear Information System (INIS)

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.)

216

Anatomical mapping of the nasal muscles and application to cosmetic surgery.  

Science.gov (United States)

We present an anatomical mapping of the most important muscles influencing the nose, incorporating constant anatomical structures, and their spatial correlations. At our disposal were the midfaces of 18 bodies of both sexes, obtained by informed consent from body donors aged between 60 and 80 years. Macroscopically, we dissected the nasal regions of eight corpses, six midfaces were prepared according to plastination histology, four by creating plastinated slices. On their way from their periosteal origin to the edge of the skin, the muscles of the nose cross the subcutaneous adipose tissue, dividing it into superficial and deep layers. The individual muscle fibers insert into the skin directly at the reticular corium. Sometimes, they reach the border of the epidermis which represents a special arrangement of corial muscle attachments. The course of the anatomical fibers of individual nasal muscles presented macroscopically and microscopically in this study offers surgeons a detailed overview of the anatomically important muscular landmarks of the midface. PMID:24863980

Konschake, Marko; Fritsch, Helga

2014-11-01

217

Avoiding the Medial Brachial Cutaneous Nerve in Brachioplasty: An Anatomical Study  

OpenAIRE

Objective: With more patients undergoing bariatric surgery procedures, there has been an increased demand on plastic surgeons to manage excess skin around the body from massive weight loss. The upper arm is one of the areas that require surgical attention. One of the complications of brachioplasty is injury to cutaneous nerves of the arm. We report our findings of the location of the medial brachial cutaneous nerve on the basis of anatomical landmarks to aid the reconstructive surgeon in plan...

Chowdhry, Saeed; Elston, Joshua B.; Lefkowitz, Todd; Wilhelmi, Bradon J.

2010-01-01

218

Factors influencing superimposition error of 3D cephalometric landmarks by plane orientation method using 4 reference points: 4 point superimposition error regression model.  

Science.gov (United States)

Superimposition has been used as a method to evaluate the changes of orthodontic or orthopedic treatment in the dental field. With the introduction of cone beam CT (CBCT), evaluating 3 dimensional changes after treatment became possible by superimposition. 4 point plane orientation is one of the simplest ways to achieve superimposition of 3 dimensional images. To find factors influencing superimposition error of cephalometric landmarks by 4 point plane orientation method and to evaluate the reproducibility of cephalometric landmarks for analyzing superimposition error, 20 patients were analyzed who had normal skeletal and occlusal relationship and took CBCT for diagnosis of temporomandibular disorder. The nasion, sella turcica, basion and midpoint between the left and the right most posterior point of the lesser wing of sphenoidal bone were used to define a three-dimensional (3D) anatomical reference co-ordinate system. Another 15 reference cephalometric points were also determined three times in the same image. Reorientation error of each landmark could be explained substantially (23%) by linear regression model, which consists of 3 factors describing position of each landmark towards reference axes and locating error. 4 point plane orientation system may produce an amount of reorientation error that may vary according to the perpendicular distance between the landmark and the x-axis; the reorientation error also increases as the locating error and shift of reference axes viewed from each landmark increases. Therefore, in order to reduce the reorientation error, accuracy of all landmarks including the reference points is important. Construction of the regression model using reference points of greater precision is required for the clinical application of this model. PMID:25372707

Hwang, Jae Joon; Kim, Kee-Deog; Park, Hyok; Park, Chang Seo; Jeong, Ho-Gul

2014-01-01

219

Surgical anatomy of the superior gluteal nerve and landmarks for its localization during minimally invasive approaches to the hip.  

Science.gov (United States)

The superior gluteal nerve (SGN) is vulnerable to damage during total hip arthroplasty and various pelvic surgeries. Recently introduced minimally invasive approaches to the hip show promise for less muscle trauma compared to conventional approaches. However, the risk of damaging the SGN has not been well documented for such alternative approaches. Therefore, we aimed to investigate the anatomic course of the SGN and to define anatomical landmarks that may be used by surgeons during minimally invasive approaches to the hip. Twenty-eight gluteal regions from 14 formalin-fixed cadavers were dissected and the course and the distances of the SGN and its branches to the tip of the greater trochanter (GT) were measured. The landmarks for standardizing the course of the SGN included the posterior inferior iliac spine (PIIS), GT, and a line (PIIS-GT) connecting these two points. The exit of the SGN was found to be at the medial one third of the PIIS-GT line and 5.4 cm from the GT. Two branching patterns were noted. The branches of the SGN were distributed lateral to the PIIS-GT line. On the basis of our study, the safe zone for the SGN was smaller than previously reported. Posterior, lateral, or anterolateral minimally invasive approaches to the hip should take into account the point of exit of the SGN and the area of distribution of its branches. A minimally invasive anterolateral approach may particularly compromise branches to the tensor fasciae latae muscle. Localization of the SGN and its branches using the anatomic landmarks defined in this study may decrease surgical morbidity. PMID:22374811

Apaydin, Nihal; Kendir, Simel; Loukas, Marios; Tubbs, R Shane; Bozkurt, Murat

2013-07-01

220

Magnetic resonance angiography: from anatomical knowledge modeling to vessel segmentation.  

Science.gov (United States)

Magnetic resonance angiography (MRA) has become a common way to study cerebral vascular structures. Indeed, it enables to obtain information on flowing blood in a totally non-invasive and non-irradiant fashion. MRA exams are generally performed for three main applications: detection of vascular pathologies, neurosurgery planning, and vascular landmark detection for brain functional analysis. This large field of applications justifies the necessity to provide efficient vessel segmentation tools. Several methods have been proposed during the last fifteen years. However, the obtained results are still not fully satisfying. A solution to improve brain vessel segmentation from MRA data could consist in integrating high-level a priori knowledge in the segmentation process. A preliminary attempt to integrate such knowledge is proposed here. It is composed of two methods devoted to phase contrast MRA (PC MRA) data. The first method is a cerebral vascular atlas creation process, composed of three steps: knowledge extraction, registration, and data fusion. Knowledge extraction is performed using a vessel size determination algorithm based on skeletonization, while a topology preserving non-rigid registration method is used to fuse the information into the atlas. The second method is a segmentation process involving adaptive sets of gray-level hit-or-miss operators. It uses anatomical knowledge modeled by the cerebral vascular atlas to adapt the parameters of these operators (number, size, and orientation) to the searched vascular structures. These two methods have been tested by creating an atlas from a 18 MRA database, and by using it to segment 30 MRA images, comparing the results to those obtained from a region-growing segmentation method. PMID:16386938

Passat, N; Ronse, C; Baruthio, J; Armspach, J-P; Maillot, C

2006-04-01

221

An Anatomically Oriented Breast Coordinate System for Mammogram Analysis  

DEFF Research Database (Denmark)

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.

Brandt, Sami; Karemore, Gopal Raghunath

2011-01-01

222

Application of landmark morphometrics to skulls representing the orders of living mammals  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Statistical analyses of geometric morphometric data have been generally restricted to the Euclidean space tangent to curved shape space. This approach is based on the knowledge that such an approximation does not affect statistical and biological conclusions, when differences among specimens' shapes are not too large. We examined the wide variation of shapes within the vertebrate class Mammalia to determine the tangent space approximation by comparing Procrustes distances in Kendall shape space to tangent space distances among 53 mammal skulls and articulated jaws belonging to almost all of the living orders. Previous studies have been restricted to relatively low taxonomic levels, implying a narrower range of shapes. Thirty-five three-dimensional (3D landmarks on the sagittal plane and right side of each specimen were digitized using a MicroScribe 3DX. Procrustes and tangent space distances between all specimens were compared using the program TPSSMALL (Rohlf, 1998b. The correlations between these distances were always greater than 0.99. Lower jaw and brain subsets of the landmarks gave similar results, while the face subset had more scatter, but nearly the same correlation. The 3D shapes, as summarized by the landmarks, were clustered and the dendrogram was compared to a currently hypothesized phylogeny. We also point out that data from landmark morphometrics are as appropriate as morphological and molecular data for cladistic analysis.

Leslie Marcus

2000-06-01

223

Evaluating the City Image: A Focus on Landmarks of Kuala Lumpur, Malaysia  

Directory of Open Access Journals (Sweden)

Full Text Available One of the main issues that have been considered about Kuala Lumpur city is its indistinguishable identity and image, partly due to the rapid development and expansion of the city structure over many decades. Inevitably, forming a distinctive city image is not an easy task as it depends primarily on the manner of reciprocal interactions between people and their surrounding built environment. This paper examines the relationship and interaction between people and the city structure, specifically through public evaluation of landmarks as one of the five elements of the city image. The people’s background and their evaluation of the landmarks’ features are examined in this study. To achieve this objective, both quantitative and qualitative data were collected using mixed-techniques involving a questionnaire survey of 120 respondents followed by an unstructured interview. The results show significant differences in the public evaluation of landmarks based on the respondents’ nationality and ethnicity. Differences in the evaluation are related to the landmark factors namely unique; memorable; legible; historic; design; scale; meaningful and color. Much effort by the local authorities is necessary to create a distinguishable image of Kuala Lumpur that reflects the city’s fusion of modern and traditional lifestyles, and diversified cultures and values.

Ahmed Raad Al Shams

2014-01-01

224

Pedro Ara anatomic museum.  

Science.gov (United States)

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

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

2006-03-01

225

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 ...

226

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 care. ... in Philadelphia. A revolution in shoulder orthopedics, the Global AP ...

227

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 care. In a few moments, you'll be able to watch a live ...

228

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)

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.

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

229

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)

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.

Juan Pablo Sorolla P

2012-12-01

230

Proposed European anatomical collections network  

OpenAIRE

Universities, colleges, medical institutions and professional societies in the past used their museums as tools to establish themselves as the rightful producers of anatomical knowledge. Anatomical and medical museums, nearly ubiquitous in the cities of Europe and the United States, exhibited and preserved anatomical specimens as well as models and sculptures – some displaying great artistic and technical finesse – which depicted human anatomy in graphic detail. A European anatomical col...

Elena Corradini; Marek Bukowski

2012-01-01

231

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

OpenAIRE

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...

C Douglas Simmons, Phd; Sajay Arthanat, Phd; Vincent J Macri, Ba

2014-01-01

232

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

Science.gov (United States)

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

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

233

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)

Full Text Available SciELO Chile | Language: English Abstract in spanish 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.

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

2013-09-01

234

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

Science.gov (United States)

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.

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

2014-03-01

235

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

Science.gov (United States)

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.

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

2010-02-01

236

Reference Man anatomical model  

Energy Technology Data Exchange (ETDEWEB)

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.

Cristy, M.

1994-10-01

237

Landmark-driven parameter optimization for non-linear image registration  

Science.gov (United States)

Image registration is one of the most common research areas in medical image processing. It is required for example for image fusion, motion estimation, patient positioning, or generation of medical atlases. In most intensity-based registration approaches, parameters have to be determined, most commonly a parameter indicating to which extend the transformation is required to be smooth. Its optimal value depends on multiple factors like the application and the occurrence of noise in the images, and may therefore vary from case to case. Moreover, multi-scale approaches are commonly applied on registration problems and demand for further adjustment of the parameters. In this paper, we present a landmark-based approach for automatic parameter optimization in non-linear intensity-based image registration. In a first step, corresponding landmarks are automatically detected in the images to match. The landmark-based target registration error (TRE), which is shown to be a valid metric for quantifying registration accuracy, is then used to optimize the parameter choice during the registration process. The approach is evaluated for the registration of lungs based on 22 thoracic 4D CT data sets. Experiments show that the TRE can be reduced on average by 0.07 mm using automatic parameter optimization.

Schmidt-Richberg, Alexander; Werner, René; Ehrhardt, Jan; Wolf, Jan-Christoph; Handels, Heinz

2011-03-01

238

Anticipatory postural activity of the deep trunk muscles differs between anatomical regions based on their mechanical advantage.  

Science.gov (United States)

The functional differentiation between regions of psoas major (PM) and quadratus lumborum (QL) may underlie a mechanical basis for recruitment of motor units across the muscle. These mechanically unique fascicle regions of these complex multifascicular muscles, PM and QL, are likely to be controlled independently by the central nervous system (CNS). Fine-wire electrodes recorded the electromyographic activity of the PM fascicles arising from the transverse process (PM-t) and vertebral body (PM-v) and the anterior (QL-a) and posterior (QL-p) layers of QL on the right side during a postural perturbation associated with rapid arm movements. The findings of this study indicate that the CNS coordinates the activity of specific regions of PM and QL independently as a component of the anticipatory postural adjustments that precedes the predictable challenge to the spine associated with limb movements. The spatial and temporal features of discrete activity of different regions within PM and QL matched their differing mechanical advantage predicted from their anatomy. These findings suggest that the CNS differentially activates individual regions within complex spine muscles to control the three-dimensional forces applied to the spine. The data also point to a sophisticated control of muscle activation that appears based on mechanical advantage. PMID:24370638

Park, R J; Tsao, H; Cresswell, A G; Hodges, P W

2014-03-01

239

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

Directory of Open Access Journals (Sweden)

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.

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

2014-06-01

240

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

241

Landmarks of History of Soil Science in Sri Lanka  

Science.gov (United States)

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

Mapa, R.

2012-04-01

242

3D face analysis : landmarking, expression recognition and beyond  

OpenAIRE

This Ph.D thesis work is dedicated to automatic facial analysis in 3D, including facial landmarking and facial expression recognition. Indeed, facial expression plays an important role both in verbal and non verbal communication, and in expressing emotions. Thus, automatic facial expression recognition has various purposes and applications and particularly is at the heart of "intelligent" human-centered human/computer(robot) interfaces. Meanwhile, automatic landmarking provides aprior knowled...

Zhao, Xi

2010-01-01

243

Object-oriented landmark recognition for UAV-navigation  

OpenAIRE

Computer vision is an ever more important means for the navigation of UAVs. Here we propose a landmark recognition system looking for salient man-made infrastructure. An object-oriented structural system is preferred since it can utilize known properties of these objects such as part-of hierarchies, mutual geometric constraints of parts, generalization etc. The structure, available for use as landmark, will vary strongly with the region the UAV is supposed to navigate in. Clear object-oriente...

Michaelsen, E.; Roschkowski, D.; Doktorski, L.; Jaeger, K.; Arens, M.

2010-01-01

244

Dispersion assessment in the location of facial landmarks on photographs.  

Science.gov (United States)

The morphological assessment of facial features using photographs has played an important role in forensic anthropology. The analysis of anthropometric landmarks for determining facial dimensions and angles has been considered in diverse forensic areas. Hence, the quantification of the error associated to the location of facial landmarks seems to be necessary when photographs become a key element of the forensic procedure. In this work, we statistically evaluate the inter- and intra-observer dispersions related to the facial landmark identification on photographs. In the inter-observer experiment, a set of 18 facial landmarks was provided to 39 operators. They were requested to mark only those that they could precisely place on 10 photographs with different poses (frontal, oblique, and lateral views). The frequency of landmark location was studied together with their dispersion. Regarding the intra-observer evaluation, three participants identified 13 facial points on five photographs classified in the frontal and oblique views. Each landmark location was repeated five times at intervals of at least 24 h. The frequency results reveal that glabella, nasion, subnasale, labiale superius, and pogonion obtained the highest location frequency in the three image categories. On the contrary, the lowest rate corresponds to labiale inferius and menton. Meanwhile, zygia, gonia, and gnathion were significantly more difficult to locate than other facial landmarks. They produced a significant effect on the dispersion depending on the pose of the image where they were placed, regardless of the type of observer that positioned them. In particular, zygia and gonia presented a statistically greater variation in the three image poses, while the location of gnathion is less precise in oblique view photographs. Hence, our findings suggest that the latter landmarks tend to be highly variable when determining their exact position. PMID:24878615

Campomanes-Álvarez, B R; Ibáñez, O; Navarro, F; Alemán, I; Cordón, O; Damas, S

2015-01-01

245

Measure of Landmark Semantic Salience through Geosocial Data Streams  

Directory of Open Access Journals (Sweden)

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.

Teriitutea Quesnot

2014-12-01

246

Anatomical and functional imaging in endocrine hypertension  

OpenAIRE

In endocrine hypertension, hormonal excess results in clinically significant hypertension. The functional imaging (such as radionuclide imaging) complements anatomy-based imaging (such as ultrasound, computed tomography, and magnetic resonance imaging) to facilitate diagnostic localization of a lesion causing endocrine hypertension. The aim of this review article is to familiarize general radiologists, endocrinologists, and clinicians with various anatomical and functional imaging techniques ...

Chaudhary, Vikas; Bano, Shahina

2012-01-01

247

Anatomy of the inferior orbital fissure: implications for endoscopic cranial base surgery.  

Science.gov (United States)

Considering many approaches to the skull base confront the inferior orbital fissure (IOF) or sphenomaxillary fissure, the authors examine this anatomy as an important endoscopic surgical landmark. In morphometric analyses of 50 adult human dry skulls from both sexes, we divided the length of the IOF into three segments (anterolateral, middle, posteromedial). Hemotoxylin- and eosin-stained sections were analyzed. Dissections were performed using transnasal endoscopy in four formalin-fixed cadaveric cranial specimens (eight sides); three endoscopic approaches to the IOF were performed. IOF length ranged from 25 to 35 mm (mean 29 mm). Length/width of the individual anterolateral, middle, and posteromedial segments averaged 6.46/5, 4.95/3.2, and 17.6/ 2.4 mm, respectively. Smooth muscle within the IOF had a consistent relationship with several important anatomical landmarks. The maxillary antrostomy, total ethmoidectomy approach allowed access to the posteromedial segment of the fissure. The endoscopic modified, medial maxillectomy approach allowed access to the middle and posterior-medial segment. The Caldwell-Luc approach allowed complete exposure of the IOF. The IOF serves as an important anatomic landmark during endonasal endoscopic approaches to the skull base and orbit. Each of the three segments provides a characteristic endoscopic corridor, unique to the orbit and different fossas surrounding the fissure. PMID:23542710

De Battista, Juan Carlos; Zimmer, Lee A; Theodosopoulos, Philip V; Froelich, Sebastien C; Keller, Jeffrey T

2012-04-01

248

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)

249

Skull base tumors  

International Nuclear Information System (INIS)

Modern imaging techniques have great importance in the diagnosis and therapy of skull-base pathologies. Many of these lesions, especially in relation to their specific location, can be evaluated using CT and MR imaging. Tumors commonly found in the anterior skull base include carcinoma, rhabdomyosarcoma, esthesioneuroblastoma and meningioma. In the central cranial fossa, nasopharyngeal carcinoma, metastases, meningioma, pituitary adenoma and neurinoma have to be considered. The most common neoplasms of the posterior skull base, including the CP angle, are neurinoma, meningioma, nasopharyngeal carcinoma, chordoma and paraganglioma. One major task of imaging is the evaluation of the exact tumor extent as well as its relationship to the neighboring neurovascular structures. The purpose of this review is to recapitulate the most important anatomical landmarks of the skull base. The typical imaging findings of the most common tumors involving the skull base are also presented. (orig.)

250

Standardized anatomic space for abdominal fat quantification  

Science.gov (United States)

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.

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

2014-03-01

251

Necessity Of Anatomical Knowledge In Thoracic Surgery.  

Directory of Open Access Journals (Sweden)

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.

Arribalzaga, Eduardo B.

2011-09-01

252

Anatomical study of spinal accessory nerve using ultrasonography  

Energy Technology Data Exchange (ETDEWEB)

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.

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

253

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

254

Quality Assurance Assessment of Diagnostic and Radiation Therapy-Simulation CT Image Registration for Head and Neck Radiation Therapy: Anatomic Region of Interest-based Comparison of Rigid and Deformable Algorithms.  

Science.gov (United States)

Purpose To develop a quality assurance (QA) workflow by using a robust, curated, manually segmented anatomic region-of-interest (ROI) library as a benchmark for quantitative assessment of different image registration techniques used for head and neck radiation therapy-simulation computed tomography (CT) with diagnostic CT coregistration. Materials and Methods Radiation therapy-simulation CT images and diagnostic CT images in 20 patients with head and neck squamous cell carcinoma treated with curative-intent intensity-modulated radiation therapy between August 2011 and May 2012 were retrospectively retrieved with institutional review board approval. Sixty-eight reference anatomic ROIs with gross tumor and nodal targets were then manually contoured on images from each examination. Diagnostic CT images were registered with simulation CT images rigidly and by using four deformable image registration (DIR) algorithms: atlas based, B-spline, demons, and optical flow. The resultant deformed ROIs were compared with manually contoured reference ROIs by using similarity coefficient metrics (ie, Dice similarity coefficient) and surface distance metrics (ie, 95% maximum Hausdorff distance). The nonparametric Steel test with control was used to compare different DIR algorithms with rigid image registration (RIR) by using the post hoc Wilcoxon signed-rank test for stratified metric comparison. Results A total of 2720 anatomic and 50 tumor and nodal ROIs were delineated. All DIR algorithms showed improved performance over RIR for anatomic and target ROI conformance, as shown for most comparison metrics (Steel test, P simulation CT section thickness. Conclusion Development of a formal ROI-based QA workflow for registration assessment demonstrated improved performance with DIR techniques over RIR. After QA, DIR implementation should be the standard for head and neck diagnostic CT and simulation CT allineation, especially for target delineation. (©) RSNA, 2014 Online supplemental material is available for this article. PMID:25380454

Mohamed, Abdallah S R; Ruangskul, Manee-Naad; Awan, Musaddiq J; Baron, Charles A; Kalpathy-Cramer, Jayashree; Castillo, Richard; Castillo, Edward; Guerrero, Thomas M; Kocak-Uzel, Esengul; Yang, Jinzhong; Court, Laurence E; Kantor, Michael E; Gunn, G Brandon; Colen, Rivka R; Frank, Steven J; Garden, Adam S; Rosenthal, David I; Fuller, Clifton D

2015-03-01

255

Occipital neuralgia: anatomic considerations.  

Science.gov (United States)

Occipital neuralgia is a debilitating disorder first described in 1821 as recurrent headaches localized in the occipital region. Other symptoms that have been associated with this condition include paroxysmal burning and aching pain in the distribution of the greater, lesser, or third occipital nerves. Several etiologies have been identified in the cause of occipital neuralgia and include, but are not limited to, trauma, fibrositis, myositis, fracture of the atlas, and compression of the C-2 nerve root, C1-2 arthrosis syndrome, atlantoaxial lateral mass osteoarthritis, hypertrophic cervical pachymeningitis, cervical cord tumor, Chiari malformation, and neurosyphilis. The management of occipital neuralgia can include conservative approaches and/or surgical interventions. Occipital neuralgia is a multifactorial problem where multiple anatomic areas/structures may be involved with this pathology. A review of these etiologies may provide guidance in better understanding occipital neuralgia. PMID:25244129

Cesmebasi, Alper; Muhleman, Mitchel A; Hulsberg, Paul; Gielecki, Jerzy; Matusz, Petru; Tubbs, R Shane; Loukas, Marios

2015-01-01

256

Anatomical relationship between the parietomastoid suture and transverse sinus. Evaluation by 3D computed tomographic angiography  

International Nuclear Information System (INIS)

The primary aim of this study was to determine whether the parietomastoid suture can be a useful landmark to localize the transverse sinus. Three-D computed tomographic angiograms in 37 cases were evaluated using the following two assessments. One defined the relationship between the extended line of the parietomastoid suture and the transverse sinus (TS). The second determined the anatomic position of the asterion relative to the transverse sigmoid junction (TSJ). In all cases, the extended line of parietomastoid suture ran parallel to the TS. In contrast, the asterion was located above the TSJ in 26 cases (70.3%), at the mid-portion in 4 cases (10.8%), and below in 7 cases (18.9%). The extended line of the parietomastoid suture appears to be a reliable indicator of the location of the TS. The parietomastoid suture can be a useful intraoperative landmark for the TS. (author)

257

The relationship between specific absorption rate and temperature elevation in anatomically based human body models for plane wave exposure from 30 MHz to 6 GHz  

Science.gov (United States)

According to the international safety guidelines/standard, the whole-body-averaged specific absorption rate (Poljak et al 2003 IEEE Trans. Electromagn. Compat. 45 141-5) and the peak spatial average SAR are used as metrics for human protection from whole-body and localized exposures, respectively. The IEEE standard (IEEE 2006 IEEE C95.1) indicates that the upper boundary frequency, over which the whole-body-averaged SAR is deemed to be the basic restriction, has been reduced from 6 to 3 GHz, because radio-wave energy is absorbed around the body surface when the frequency is increased. However, no quantitative discussion has been provided to support this description especially from the standpoint of temperature elevation. It is of interest to investigate the maximum temperature elevation in addition to the core temperature even for a whole-body exposure. In the present study, using anatomically based human models, we computed the SAR and the temperature elevation for a plane-wave exposure from 30 MHz to 6 GHz, taking into account the thermoregulatory response. As the primary result, we found that the ratio of the core temperature elevation to the whole-body-averaged SAR is almost frequency independent for frequencies below a few gigahertz; the ratio decreases above this frequency. At frequencies higher than a few gigahertz, core temperature elevation for the same whole-body averaged SAR becomes lower due to heat convection from the skin to air. This lower core temperature elevation is attributable to skin temperature elevation caused by the power absorption around the body surface. Then, core temperature elevation even for whole-body averaged SAR of 4 W kg-1 with the duration of 1 h was at most 0.8 °C, which is smaller than a threshold considered in the safety guidelines/standard. Further, the peak 10 g averaged SAR is correlated with the maximum body temperature elevations without extremities and pinna over the frequencies considered. These findings were confirmed for seven models, including models of a child and a pregnant female. Thus, the current basic restriction for whole-body exposure in the international guidelines is conservative. Peak spatial-averaged SAR can be used as a metric for estimating local temperature elevation even for whole-body exposure. Our computational results also support the description in the IEEE standard about the reduction of the upper applicable frequency of whole-body-averaged SAR from 6 and 3 GHz the power density reference level is more conservative than the basic restriction limit for the whole-body averaged SAR from the standpoint of temperature elevation.

Hirata, Akimasa; Laakso, Ilkka; Oizumi, Takuya; Hanatani, Ryuto; Chan, Kwok Hung; Wiart, Joe

2013-02-01

258

Three-dimensional B-spline-based intersubject nonrigid registration with geodesic closest points constraints  

Science.gov (United States)

Due to the variance between subjects, there is usually ambiguity in intensity-based intersubject registration. The topological constraint in the brain cortical surface might be violated because of the highly convolved nature of the human cortical cortex. We propose an intersubject brain registration method by combining the intensity and the geodesic closest point-based similarity measurements. Each of the brain hemispheres can be topologically equal to a sphere and a one-to-one mapping of the points on the spherical surfaces of the two subjects can be achieved. The correspondences in the cortical surface are obtained by searching the geodesic closest points in the spherical surface. The corresponding features on the cortical surfaces between subjects are then used as anatomical landmarks for intersubject registration. By adding these anatomical constraints of the cortical surfaces, the intersubject registration results are more anatomically plausible and accurate. We validate our method by using real human datasets. Experimental results in visual inspection and alignment error show that the proposed method performs better than the typical joint intensity- and landmark-distance-based methods.

Zhang, Zhijun; Liu, Feng; Deng, Fuqin; Tsui, Hungtat

2014-11-01

259

An anatomical account of somatoparaphrenia.  

Science.gov (United States)

Somatoparaphrenia is a delusional belief whereby a patient feels that a paralyzed limb does not belong to his body; the symptom is typically associated with unilateral neglect and most frequently with anosognosia for hemiplegia. This association of symptoms makes anatomical inference based on single case studies not sufficiently specific. On the other hand, the only three anatomical group studies on somatoparaphrenia are contradictory: the right posterior insula, the supramarginal gyrus and the posterior corona radiata, or the right medial or orbito-frontal regions were all proposed as specific lesional correlates. We compared 11 patients with and 11 without somatoparaphrenia matched for the presence and severity of other associated symptoms (neglect, motor deficits and anosognosia). To take into account the frequent association of SP and neglect and hemiplegia, patients with and without somatoparaphrenia were also compared with a group of fifteen right brain damage patients without neglect and hemiplegia. We found a lesion pattern involving a fronto-temporo-parietal network typically associated with spatial neglect, hemiplegia and anosognosia. Somatoparaphrenic patients showed an additional lesion pattern primarily involving white matter and subcortical grey structures (thalamus, basal ganglia and amygdala). Further cortical damage was present in the middle and inferior frontal gyrus, postcentral gyrus and hippocampus. We propose that somatoparaphrenia occurs providing that a distributed cortical lesion pattern is present together with a subcortical lesion load that prevents most sensory input from being processed in neocortical structures; involvement of deep cortical and subcortical grey structures of the temporal lobe may contribute to reduce the sense of familiarity experienced by somatoparaphrenic patients for their paralyzed limb. PMID:21774922

Gandola, Martina; Invernizzi, Paola; Sedda, Anna; Ferrè, Elisa R; Sterzi, Roberto; Sberna, Maurizio; Paulesu, Eraldo; Bottini, Gabriella

2012-10-01

260

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)

261

Towards Anatomic Scale Agent-Based Modeling with a Massively Parallel Spatially Explicit General-Purpose Model of Enteric Tissue (SEGMEnT_HPC).  

Science.gov (United States)

Perhaps the greatest challenge currently facing the biomedical research community is the ability to integrate highly detailed cellular and molecular mechanisms to represent clinical disease states as a pathway to engineer effective therapeutics. This is particularly evident in the representation of organ-level pathophysiology in terms of abnormal tissue structure, which, through histology, remains a mainstay in disease diagnosis and staging. As such, being able to generate anatomic scale simulations is a highly desirable goal. While computational limitations have previously constrained the size and scope of multi-scale computational models, advances in the capacity and availability of high-performance computing (HPC) resources have greatly expanded the ability of computational models of biological systems to achieve anatomic, clinically relevant scale. Diseases of the intestinal tract are exemplary examples of pathophysiological processes that manifest at multiple scales of spatial resolution, with structural abnormalities present at the microscopic, macroscopic and organ-levels. In this paper, we describe a novel, massively parallel computational model of the gut, the Spatially Explicitly General-purpose Model of Enteric Tissue_HPC (SEGMEnT_HPC), which extends an existing model of the gut epithelium, SEGMEnT, in order to create cell-for-cell anatomic scale simulations. We present an example implementation of SEGMEnT_HPC that simulates the pathogenesis of ileal pouchitis, and important clinical entity that affects patients following remedial surgery for ulcerative colitis. PMID:25806784

Cockrell, Robert Chase; Christley, Scott; Chang, Eugene; An, Gary

2015-01-01

262

Ultrasound Anatomical Visualization of the rabbit liver  

Directory of Open Access Journals (Sweden)

Full Text Available The topic was to investigate the anatomical features of the rabbit liver by two- and three-dimensional ultrasonography. Eighteen sexually mature healthy clinically New Zealand rabbits aged eight months were studied. Two-dimensional ultarsonographic anatomical image of the rabbit liver presented it in the cranial abdominal region as a relatively hypoechoic finding. Its contours were regular and in close contact with the hyperechoic diaphragm. Liver parenchyma was heterogeneous. The gall bladder was visualized as an oval soft tissue structure, filled with anechoic content. Its walls were hypoechoic. Two-dimensional ultarsonographic anatomical image of left hepatic lobe was sharply distinguished to right hepatic lobe’s outlines. In three – dimensional ultrasonogarphic anatomical study, the organ image was in three orthogonal planes. Its relief was regular and uninterrupted. Left hepatic lobe was found on the left and the right hepatic lobe was a soft tissue point for gall bladder position. Left and lateral was left lateral hepatic lobe. It was covered partly by left medial hepatic lobe. The right hepatic lobe was visualized as a single structure. The gall bladder was an oval finding. Its walls were hyperechoic and regular, without roughness. The results could be used as a base for modern interpretation of rabbit liver anatomy.

Kamelia Dimcheva Stamatova-Yovcheva

2014-11-01

263

A cubic B-spline-based hybrid registration of lung CT images for a dynamic airway geometric model with large deformation  

International Nuclear Information System (INIS)

The goal of this study is to develop a matching algorithm that can handle large geometric changes in x-ray computed tomography (CT)-derived lung geometry occurring during deep breath maneuvers. These geometric relationships are further utilized to build a dynamic lung airway model for computational fluid dynamics (CFD) studies of pulmonary air flow. The proposed algorithm is based on a cubic B-spline-based hybrid registration framework that incorporates anatomic landmark information with intensity patterns. A sequence of invertible B-splines is composed in a multiresolution framework to ensure local invertibility of the large deformation transformation and a physiologically meaningful similarity measure is adopted to compensate for changes in voxel intensity due to inflation. Registrations are performed using the proposed approach to match six pairs of 3D CT human lung datasets. Results show that the proposed approach has the ability to match the intensity pattern and the anatomical landmarks, and ensure local invertibility for large deformation transformations. Statistical results also show that the proposed hybrid approach yields significantly improved results as compared with approaches using either landmarks or intensity alone.

264

Proposed European anatomical collections network  

Directory of Open Access Journals (Sweden)

Full Text Available Universities, colleges, medical institutions and professional societies in the past used their museums as tools to establish themselves as the rightful producers of anatomical knowledge. Anatomical and medical museums, nearly ubiquitous in the cities of Europe and the United States, exhibited and preserved anatomical specimens as well as models and sculptures – some displaying great artistic and technical finesse – which depicted human anatomy in graphic detail. A European anatomical collection network proposes to obtain, collect, and analyze a wide range of information about anatomical collections in Europe. For our proposal it is important to focus the attention on ‘how’ as well as ‘what’ has been collected, to the strategies adopted for showing the collections, to the people who had access to the collections and the degree to which their prior experiences and expectations may have shaped their responses to it. It is also important to consider the geographical location and origins of anatomical collections, their anatomical models and specimens, the contents of lectures, the audiences targeted and also the questions raised in historical, sociological and anthropological literature about anatomy.

Elena Corradini

2012-10-01

265

Developing patient-specific anatomic models for validation of cardiac ablation guidance procedures  

Science.gov (United States)

Image-guided cardiac ablation has the potential to decrease procedure times and improve clinical outcome for patients with cardiac arrhythmias. There are several proposed methods for integrating patient-specific anatomy into the cardiac ablation procedure; however, these methods require thorough validation. One of the primary challenges in validation is determining ground truth as a standard for comparison. Some validation protocols have been developed for animals models and even in patients; however, these methods can be costly to implement and may increase the risk to patients. We have developed an approach to building realistic patient-specific anatomic models at a low-cost in order to validate the guidance procedure without introducing additional risk to the patients. Using a pre-procedural cardiac computed tomography scan, the blood pool of the left and right atria of a patient are segmented semi-manually. In addition, several anatomical landmarks are identified in the image data. The segmented atria and landmarks are converted into a polygonalized model which is used to build a thin-walled patient-specific blood pool model in a stereo-lithography system. Thumbscrews are inserted into the model at the landmarks. The entire model is embedded in a platinum silicone material which has been shown to have tissue-mimicking properties relative to ultrasound. Once the pliable mold has set, the blood pool model is extracted by dissolving the rigid material. The resulting physical model correctly mimics a specific patient anatomy with embedded fiducals which can be used for validation experiments. The patient-specific anatomic model approach may also be used for pre-surgical practice and training of new interventionalists.

Holmes, David, III; Rettmann, Maryam; Cameron, Bruce; Camp, Jon; Robb, Richard

2008-03-01

266

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 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.

267

The free sartorius flap: clinical cases and anatomical study.  

Science.gov (United States)

The thigh is a rich source of tissue for free flap harvest. The anterolateral thigh and gracilis flaps are most commonly used. The sartorius flap is an easily harvested flap that can be raised with the leg in the anatomically extended position without rotation. The cutaneous landmarks are readily identified and so the relevant perforators can be quickly found. Pedicle dissection is quick and easy, allowing the flap to be raised in a short time. We report our experience of using this flap both as a free muscle-only flap and as a free fasciocutaneous perforator flap for soft-tissue reconstruction in the lower limb. An anatomical study was also carried out to examine the vascular anatomy of the sartorius muscle flap and the cutaneous perforator flap. Twenty limbs from soft fixed adult cadavers were dissected and the position, length, diameter and cutaneous extension of all segmental pedicles, from the anterior superior iliac spine (ASIS) to the medial femoral condyle, were measured. Fourteen out of 20 (70%) sartorius muscles had at least one musculocutaneous perforator and, of these muscles, 13 (93%) had at least one musculocutaneous perforator that was found at 20±3cm from the ASIS. The free sartorius flap is a useful addition to flap choice from the thigh and carries a predictable cutaneous perforator in the majority of cases, allowing a fasciocutaneous perforator flap to be quickly and reliably raised with minimal donor-site morbidity. PMID:22771162

Ng, Darren; Vesely, Martin

2012-12-01

268

New anatomically oriented transapical aortic valve implantation.  

Science.gov (United States)

Transapical aortic valve implantation has become a routine procedure to treat high-risk patients in some centers. To facilitate optimal positioning, a new self-centering valve design with anatomic orientation of the commissures has been developed. This self-expanding nitinol stent-based valve has 3 support arms that are placed within the aortic sinuses. Here we report implantation of this new valve in a patient. The valve demonstrated excellent function with a low transvalvular gradient. PMID:19231421

Falk, Volkmar; Schwammenthal, Ehud E; Kempfert, Jörg; Linke, Axel; Schuler, Gerhard; Mohr, Friedrich W; Walther, Thomas

2009-03-01

269

The Giessen virtual environment laboratory: human wayfinding and landmark salience.  

Science.gov (United States)

In our virtual environment laboratory, we focus on different topics in human spatial cognition with projects on landmark salience, route knowledge, and survey knowledge. Within this laboratory note, we provide an overview of previous, current, and future work with our virtual environment SQUARELAND. PMID:21279666

Röser, Florian; Hamburger, Kai; Knauff, Markus

2011-05-01

270

On-line SLAM using clustered landmarks with omnidirectional vision  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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.

Jun, Okamoto Jr.; Vitor Campanholo, Guizilini.

2010-12-01

271

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

Science.gov (United States)

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…

Hund, Alycia M.

2010-01-01

272

An Adaptive Algorithm for Finding Frequent Sets in Landmark Windows  

DEFF Research Database (Denmark)

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.

Dang, Xuan-Hong; Ong, Kok-Leong

2012-01-01

273

Children's Wayfinding: Response to Instructions to Use Environmental Landmarks.  

Science.gov (United States)

Examined the ability of 144 children of 6 and 12 years to respond to instructions to use environmental landmarks when leading the way. Children who were told they would lead the way did not prepare more adequately than children who were not told. Children did benefit from instructions to attend to environmental features. (RJC)

Cornell, Edward H.; And Others

1989-01-01

274

On-line SLAM using clustered landmarks with omnidirectional vision  

Directory of Open Access Journals (Sweden)

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 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 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.

Jun Okamoto Jr.

2010-12-01

275

Developmental Changes in Young Children's Spatial Memory and Language in Relation to Landmarks  

Science.gov (United States)

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,…

Hund, Alycia M.; Naroleski, Amber R.

2008-01-01

276

Audible Signage as a Wayfinding Aid: Verbal Landmark versus Talking Signs.  

Science.gov (United States)

Comparison by 40 users of 2 technologies--Verbal Landmark and Talking Signs--that provide speech messages to hand-held receivers for blind travelers found that, on all measures, the Talking Signs system proved superior to the Verbal Landmark system. This was attributed to Verbal Landmark's more cognitively demanding technology. (DB)

Bentzen, B. L.; Mitchell, P. A.

1995-01-01

277

Anatomic Imaging of the Prostate  

OpenAIRE

The important role of magnetic resonance imaging (MRI) in the anatomic evaluation, detection, and staging of prostate cancer is well established. This paper focuses on the pertinent embryologic, anatomic, and imaging facts regarding both the normal prostate and the several examples of prostate cancers as well as staging implications. The discussion primarily includes findings related to T2-weighted imaging as opposed to the other functional sequences, including diffusion weighted imaging (DWI...

Anil Bhavsar; Sadhna Verma

2014-01-01

278

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)

279

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.)

280

Applying the functional abnormality ontology pattern to anatomical functions  

Directory of Open Access Journals (Sweden)

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.

Hoehndorf Robert

2010-03-01

281

A surgical view of the superior nasal turbinate: anatomical study.  

Science.gov (United States)

Differences of the superior nasal turbinate (SNT), presence of the supreme nasal turbinate (SpNT) and measurements of opening sphenoid sinus (OSS) are consistent anatomical landmarks that allow for safe entrances, such as posterior ethmoidectomy and sphenoid sinusotomy. The purpose of study was to investigate the anatomical details of the SNT for approaching the OSS on 20 specimens of adult cadavers under an operating microscope. The SNT and SpNT were localized more perpendicular than parallel to their axes. The SpNT structure was observed in 12 specimens (60%) and it was classified into three types. Type A SpNT was shortest of all turbinates (58.3%). In types B and C, SpNT was equal or larger than the SNT. These types were seen in 41.7% of specimens. In 11 specimens, posterior ethmoidal cells opened to supreme nasal meatus. In 7 specimens, there was one opening to supreme nasal meatus, while 2 openings were detected in 12 specimens, and 3 openings were seen in 1 specimen. All these openings belonged to posterior ethmoidal cells. To determine the position of the OSS, distances between some anatomical points were measured. In cases where the SpNT is present or the SpNT is bigger than the SNT, it is certain that a different method will be applied during the procedure in the nasal cavity. The SNT and the SpNT may easily be injured by unrecognized dissection in types B and C, leading to the disruption of its olfactory neuroepithelium and possibly to postoperative hyposmia. PMID:20012078

Orhan, Mustafa; Govsa, Figen; Saylam, Canan

2010-06-01

282

Capturing the Multiscale Anatomical Shape Variability with Polyaffine Transformation Trees  

OpenAIRE

Mandible fractures are classified depending on their location. In clinical practice, locations are grouped into regions at different scales according to anatomical, functional and esthetic considerations. Implant design aims at defining the optimal implant for each patient. Emerging population-based techniques analyze the anatomical variability across a population and perform statistical analysis to identify an optimal set of implants. Current efforts are focused on finding clusters of patien...

Seiler, Christof; Pennec, Xavier; Reyes, Mauricio

2012-01-01

283

ROLE OF ANATOMICAL OBSTRUCTION IN THE PATHOGENESIS OF CHRONIC SINUSITIS  

OpenAIRE

Sinusitis is a commonly diagnosed condition in the general population.This article is a study to asses the role of anatomical obstruction in the pathogenesis of chronic sinusitis,based on symptomatology and radiological findings of the patients.The frequency of major anatomical variants like deviated nasal septum,concha bullosa and paradoxical middle turbinate leading to chronic sinusitis have been analyzed.Most of the time the obstruction at osteomeatal complex leading to chronic sinusitis i...

Balasubramanian Thiagarajan; Yahia Abdul Basith

2012-01-01

284

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)

285

Exploring brain function from anatomical connectivity  

Directory of Open Access Journals (Sweden)

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.

GorkaZamora-López

2011-06-01

286

Shape analysis of simulated breast anatomical structures  

Science.gov (United States)

Recent advances in high-resolution 3D breast imaging, namely, digital breast tomosynthesis and dedicated breast CT, have enabled detailed analysis of the shape and distribution of anatomical structures in the breast. Such analysis is critically important, since the projections of breast anatomical structures make up the parenchymal pattern in clinical images which can mask the existing abnormalities or introduce false alarms; the parenchymal pattern is also correlated with the risk of cancer. As a first step towards the shape analysis of anatomical structures in the breast, we have analyzed an anthropomorphic software breast phantom. The phantom generation is based upon the recursive splitting of the phantom volume using octrees, which produces irregularly shaped tissue compartments, qualitatively mimicking the breast anatomy. The shape analysis was performed by fitting ellipsoids to the simulated tissue compartments. The ellipsoidal semi-axes were calculated by matching the moments of inertia of each individual compartment and of an ellipsoid. The distribution of Dice coefficients, measuring volumetric overlap between the compartment and the corresponding ellipsoid, as well as the distribution of aspect ratios, measuring relative orientations of the ellipsoids, were used to characterize various classes of phantoms with qualitatively distinctive appearance. A comparison between input parameters for phantom generation and the properties of fitted ellipsoids indicated the high level of user control in the design of software breast phantoms. The proposed shape analysis could be extended to clinical breast images, and used to inform the selection of simulation parameters for improved realism.

Contijoch, Francisco; Lynch, Jennifer M.; Pokrajac, David D.; Maidment, Andrew D. A.; Bakic, Predrag R.

2012-03-01

287

Fusion of WiFi, smartphone sensors and landmarks using the Kalman filter for indoor localization.  

Science.gov (United States)

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

Chen, Zhenghua; Zou, Han; Jiang, Hao; Zhu, Qingchang; Soh, Yeng Chai; Xie, Lihua

2015-01-01

288

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

289

The influence of off-screen landmarks on user orientation  

OpenAIRE

Maps displayed on hand held devices, such as smartphones; provide limited visibility due to their small screen display. In order to overcome display limitations, researchers have developed new techniques that point users to objects and landmarks located off-screen, which is known as an “off-screen interface”. Since this is a new type of map interface, there is little information regarding the effect it has on the user’s perception of the environment and spatial orientation abilities. ...

Korda, Amichai

2014-01-01

290

AUTOMATIC DETECTION AND CLASSIFICATION OF RETINAL VASCULAR LANDMARKS  

Directory of Open Access Journals (Sweden)

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.

Hadi Hamad

2014-06-01

291

Dung beetles ignore landmarks for straight-line orientation.  

Science.gov (United States)

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

Dacke, Marie; Byrne, Marcus; Smolka, Jochen; Warrant, Eric; Baird, Emily

2013-01-01

292

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.

293

Anatomic Total Shoulder System  

Medline Plus

Full Text Available ... would be his subscapularis. This is a bicipital groove. We have taken out his biceps and tenodisted ... quite. Almost to the base of the bicipital groove but not quite. I think it's important to ...

294

Resultados funcionales y anatómicos en la facoemulsificación coaxial estándar mediante la técnica de multichop / Functional and anatomical results of standard coaxial phacoemulsification based on the multichop technique  

Scientific Electronic Library Online (English)

Full Text Available SciELO Cuba | Language: Spanish Abstract in spanish OBJETIVOS: Describir los resultados funcionales y anatómicos obtenidos con la facoemulsificación coaxial estándar por la técnica de multichop en la cirugía de catarata. MÉTODOS: Estudio descriptivo, longitudinal y prospectivo en el período comprendido entre septiembre de 2005 y mayo de 2007, de paci [...] entes operados de catarata en el Instituto Cubano de Oftalmología "Ramón Pando Ferrer". RESULTADOS: El poder del ultrasonido promedio fue de 20,7 %, el tiempo de ultrasonido medio fue de 46 segundos y el tiempo efectivo de facoemulsificación promedio fue de 10,2 s; existió relación significativa entre la dureza del núcleo y el tiempo de ultrasonido empleado (p Abstract in english OBJECTIVES: To describe the functional and anatomical results achieved in standard coaxial phacoemulsification using multichop technique in the cataract surgery. METHODS: Prospective longitudinal and descriptive study of patients operated on from cataract at "Ramón Pando Ferrer" Cuban Institute of O [...] phthalmology, conducted from September 2005 to May 2007. RESULTS: The average ultrasound power was 20,7 %, the average ultrasound time was 46 seconds and the average effective phaco time was 10,3 seconds; there was significant relation between nucleus hardness and time of ultrasound (p

Neisy, Bernal Reyes; Luis, Curbelo Cunill; Alejandro, Arias Díaz.

2009-12-01

295

Microarray data mining using landmark gene-guided clustering  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Clustering is a popular data exploration technique widely used in microarray data analysis. Most conventional clustering algorithms, however, generate only one set of clusters independent of the biological context of the analysis. This is often inadequate to explore data from different biological perspectives and gain new insights. We propose a new clustering model that can generate multiple versions of different clusters from a single dataset, each of which highlights a different aspect of the given dataset. Results By applying our SigCalc algorithm to three yeast Saccharomyces cerevisiae datasets we show two results. First, we show that different sets of clusters can be generated from the same dataset using different sets of landmark genes. Each set of clusters groups genes differently and reveals new biological associations between genes that were not apparent from clustering the original microarray expression data. Second, we show that many of these new found biological associations are common across datasets. These results also provide strong evidence of a link between the choice of landmark genes and the new biological associations found in gene clusters. Conclusion We have used the SigCalc algorithm to project the microarray data onto a completely new subspace whose co-ordinates are genes (called landmark genes, known to belong to a Biological Process. The projected space is not a true vector space in mathematical terms. However, we use the term subspace to refer to one of virtually infinite numbers of projected spaces that our proposed method can produce. By changing the biological process and thus the landmark genes, we can change this subspace. We have shown how clustering on this subspace reveals new, biologically meaningful clusters which were not evident in the clusters generated by conventional methods. The R scripts (source code are freely available under the GPL license. The source code is available [see Additional File 1] as additional material, and the latest version can be obtained at http://www4.ncsu.edu/~pchopra/landmarks.html. The code is under active development to incorporate new clustering methods and analysis. Additional file 1 R source code file Click here for file

Cho HyungJun

2008-02-01

296

PET image reconstruction with anatomical edge guided level set prior  

International Nuclear Information System (INIS)

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 he 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.

297

Evaluating the Reliability of Anatomic Landmarks in Safe Lumbar Puncture Using Magnetic Resonance Imaging: Does Sex Matter?  

OpenAIRE

Aim. To determine the level of the conus medullaris-Tuffier's line, and conus medullaris-Tuffier's line distance using imaging and evaluate their relation to age and gender. Methods. We performed a cross-sectional study of 189 adult participants, who underwent MR imaging of lumbosacral spine. Each vertebra was divided into 3 equal segments (upper, middle, and lower), and intervertebral disc space was also assumed as one segment. All segments from T12 upper segment to L5S1 intervertebral d...

Maryam Rahmani; Seyed Mehran Vaziri Bozorg; Ahmad Reza Ghasemi Esfe; Afsaneh Morteza; Omid Khalilzadeh; Elham Pedarzadeh; Madjid Shakiba

2011-01-01

298

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)

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

Jussara Rocha Ferreira

2001-05-01

299

Parametric Anatomical Modeling: a method for modeling the anatomical layout of neurons and their projections  

OpenAIRE

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...

Martin Pyka; Sebastian Klatt

2014-01-01

300

Bronchopulmonary segments approximation using anatomical atlas  

Science.gov (United States)

Bronchopulmonary segments are valuable as they give more accurate localization than lung lobes. Traditionally, determining the segments requires segmentation and identification of segmental bronchi, which, in turn, require volumetric imaging data. In this paper, we present a method for approximating the bronchopulmonary segments for sparse data by effectively using an anatomical atlas. The atlas is constructed from a volumetric data and contains accurate information about bronchopulmonary segments. A new ray-tracing based image registration is used for transferring the information from the atlas to a query image. Results show that the method is able to approximate the segments on sparse HRCT data with slice gap up to 25 millimeters.

Busayarat, Sata; Zrimec, Tatjana

2007-03-01

301

Anatomical structure of Polystichum Roth ferns rachises  

Directory of Open Access Journals (Sweden)

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.

Oksana V. Tyshchenko

2012-03-01

302

Dominance of the odometer over serial landmark learning in honeybee navigation  

Science.gov (United States)

Honeybees use their visual flow field to measure flight distance. It has been suggested that the experience of serial landmarks encountered on the flight toward a feeding place contributes to distance estimation. Here, we address this question by tracing the flight paths of individual bees with a harmonic radar system. Bees were trained along an array of three landmarks (tents), and the distance between these landmarks was either increased or decreased under two test conditions. We find that absolute distance estimation dominates the search for the feeding place, but serial position effects are also found. In the latter case, bees search only or additionally at locations determined by serial experience of the landmarks.

Menzel, Randolf; Fuchs, Jacqueline; Nadler, Leonard; Weiss, Benjamin; Kumbischinski, Nicole; Adebiyi, Daniel; Hartfil, Sergej; Greggers, Uwe

2010-08-01

303

Agreement between anatomic and ultrasound measurements of femoral trochlear depth  

DEFF Research Database (Denmark)

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 ultrasonographic measurements of trochlear depth using the red fox hind limb as a canine surrogate, dividing the trochlea into five regions from the origin of the caudal cruciate ligament to the proximal aspect of the trochlea. We found reasonable agreement between anatomic and ultrasonographic measurements as assessed by Bland-Altman difference charting and limits of agreement (approximately ±0.7mm). Differences may be accounted for by ultrasound probe positioning errors, which should be taken into consideration during clinical investigations. Skyline views were difficult to standardise to a distinct position in the trochlea but appeared to centre around the middle of the trochlea: the proximal section of the trochlea has been suggested to be most critical in medial patellar luxation, and thus the usefulness of this view is questionable. Trochlear depth in this study population was approximately 30% of patellar depth over the five regions examined. Measurement reliability for the ultrasonographic examinations was markedly less that for the skyline views (repeatability coefficient of 0.5mm vs 0.25mm), but still adequate for clinical use. A likely reason is the relative amount of detail recorded in the 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.

Miles, James Edward; Westrup, Ulrik

304

Based On Edge Extraction of ASM Automatic Landmark Placement  

OpenAIRE

In the Active Shape Model, the most time consuming and scientifically unsatisfactory part of building shape models is the labeling of the training images. Manually placing hundreds (in 2D) of points on every image is both tedious and error prone. To reduce the burden, the combination of the image edge information and the traditional manual calibration methods have been developed. This method improves the calibration accuracy, and obtains more accurate statistical shape model and local texture...

Zhang Liguo; Li Xiaolin; Li Huijuan

2012-01-01

305

Anatomic variations on PNS CT  

International Nuclear Information System (INIS)

To illustrate frequently encountered anatomic variations on PNS computed tomography(CT) and to assess their clinical significance. CT findings of 1523 patients, who underwent PNS CT with no history of sinus surgery, were reviewed, and prevalence of each anatomic variation and its relationship with mucociliary clearance pathway was evaluated. Two categories of anatomic variations were encountered. The first group included variations of the turbinates, such as concha bullosa(28.6%), paradoxical middle turbinate(31.5%), of the uncinate process, such as medially bent or folded(36.3%), laterally bent(3.7%) or uncinate bulla(0.5%), of the ethmoidal sinus, such as Haller's cell(28.2%), large agger nasi cell(9.6%) or large ethmoidal bulla(23.5%) and nasal septal deviation(24.1%), which might cause obstruction of mucociliary clearance pathway and thus give rise to secondary obstructive sinusitis. The second group included Onodi cell(1.4%) and medial depression of the lamina papyracea(3.5%), which were not related with obstructive sinusitis. 87 cases of large agger nasi cell were associated with obstruction of nasofrontal recess. Large ethmoidal bulla(452 cases), Haller's cell(245 case) and true concha bullosa(25 cases) contributed to narrowing of the infundibulum. Medially bent uncinate process(220 cases), concha bullosa(157 cases), paradoxical middle turbinate(126 cases) and nasal septal deviation(93 case) were observed in middle meatal obstruction and supreme concha(3 case) al obstruction and supreme concha(3 case) accompanied sphenoethmoidal recess obstruction. Recognition of anatomic variations on PNS CT is important to build a treatment plan in patients with obstructive sinusitis as they may represent causes of the disease, and to avoid critical complications during functional endoscopic sinus surgery

306

Experience in Aligning Anatomical Ontologies  

OpenAIRE

An ontology is a formal representation of a domain modeling the entities in the domain and their relations. When a domain is represented by multiple ontologies, there is need for creating mappings among these ontologies in order to facilitate the integration of data annotated with these ontologies and reasoning across ontologies. The objective of this paper is to recapitulate our experience in aligning large anatomical ontologies and to reflect on some of the issues and challenges encountered...

Zhang, Songmao; Bodenreider, Olivier

2007-01-01

307

Anatomical Considerations of the Suprascapular Nerve in Rotator Cuff Repairs  

Science.gov (United States)

Introduction. When using the double interval slide technique for arthroscopic repair of chronic large or massive rotator cuff tears, the posterior interval release is directed toward the scapular spine until the fat pad that protects the suprascapular nerve is reached. Injury to the suprascapular nerve can occur due to the nerve's proximity to the operative field. This study aimed to identify safe margins for avoiding injury to the suprascapular nerve. Materials and Methods. For 20 shoulders in ten cadavers, the distance was measured from the suprascapular notch to the glenoid rim, the articular margin of the rotator cuff footprint, and the lateral border of the acromion. Results. From the suprascapular notch, the suprascapular nerve coursed an average of 3.42?cm to the glenoid rim, 5.34?cm to the articular margin of the rotator cuff footprint, and 6.09?cm to the lateral border of the acromion. Conclusions. The results of this study define a safe zone, using anatomic landmarks, to help surgeons avoid iatrogenic injury to the suprascapular nerve when employing the double interval slide technique in arthroscopic repair of the rotator cuff. PMID:24724030

Tom, James A.; Shah, Mitesh P.; Lee, Dan J.; Cerynik, Douglas L.; Amin, Nirav H.

2014-01-01

308

Anatomical considerations of the suprascapular nerve in rotator cuff repairs.  

Science.gov (United States)

Introduction. When using the double interval slide technique for arthroscopic repair of chronic large or massive rotator cuff tears, the posterior interval release is directed toward the scapular spine until the fat pad that protects the suprascapular nerve is reached. Injury to the suprascapular nerve can occur due to the nerve's proximity to the operative field. This study aimed to identify safe margins for avoiding injury to the suprascapular nerve. Materials and Methods. For 20 shoulders in ten cadavers, the distance was measured from the suprascapular notch to the glenoid rim, the articular margin of the rotator cuff footprint, and the lateral border of the acromion. Results. From the suprascapular notch, the suprascapular nerve coursed an average of 3.42?cm to the glenoid rim, 5.34?cm to the articular margin of the rotator cuff footprint, and 6.09?cm to the lateral border of the acromion. Conclusions. The results of this study define a safe zone, using anatomic landmarks, to help surgeons avoid iatrogenic injury to the suprascapular nerve when employing the double interval slide technique in arthroscopic repair of the rotator cuff. PMID:24724030

Tom, James A; Mesfin, Addisu; Shah, Mitesh P; Javandel, Mitra; Lee, Dan J; Cerynik, Douglas L; Amin, Nirav H

2014-01-01

309

Anatomical study of the pigs temporal bone by microdissection  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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.

Leandro de Borborema, Garcia; José Santos Cruz de, Andrade; José Ricardo Gurgel, Testa.

310

[On the sources of the anatomical illustrations appearing in Quanti-xinlun].  

Science.gov (United States)

Quanti-xinlun by Hobson is frequently considered to have introduced European scientific anatomy to modern China. It contains numbers of precise anatomical illustrations which surpass by far those found in the Chinese traditional medical books. The impact of Quanti-xinlun derived mainly from the optical effects based on the anatomical illustrations. The present study clarifies for the first time the sources of the anatomical illustrations as being mostly from Wilson's "A System of Human Anatomy" and Carpenter's "Animal Physiology". However in Quanti-xinlun, the editorial sophistication present in the source books was abandoned, with the result that the anatomical contents were extremely minimized. In view of modern Chinese medical history, Quanti-xinlun provided an outline of anatomical knowledge, rather than a textbook encompassing anatomical details. It is concluded that Quanti-xinlun was intended to introduce the European way of thinking at the level of popular science. PMID:20503782

Matsumoto, Hideshi; Sakai, Tatsuo

2009-12-01

311

Landmarks in nature to support wayfinding: the effects of seasons and experimental methods.  

Science.gov (United States)

Landmarks constitute an essential basis for a structural understanding of the spatial environment. Therefore, they are crucial factors in external spatial representations such as maps and verbal route descriptions, which are used to support wayfinding. However, selecting landmarks for these representations is a difficult task, for which an understanding of how people perceive and remember landmarks in the environment is needed. We investigated the ways in which people perceive and remember landmarks in nature using the thinking aloud and sketch map methods during both the summer and the winter seasons. We examined the differences between methods to identify those landmarks that should be selected for external spatial representations, such as maps or route descriptions, in varying conditions. We found differences in the use of landmarks both in terms of the methods and also between the different seasons. In particular, the participants used passage and tree-related landmarks at significantly different frequencies with the thinking aloud and sketch map methods. The results are likely to reflect the different roles of the landmark groups when using the two methods, but also the differences in counting landmarks when using both methods. Seasonal differences in the use of landmarks occurred only with the thinking aloud method. Sketch maps were drawn similarly in summertime and wintertime; the participants remembered and selected landmarks similarly independent of the differences in their perceptions of the environment due to the season. The achieved results may guide the planning of external spatial representations within the context of wayfinding as well as when planning further experimental studies. PMID:23392783

Kettunen, Pyry; Irvankoski, Katja; Krause, Christina M; Sarjakoski, L Tiina

2013-08-01

312

Manual palpation of lumbo-pelvic landmarks: a validity study.  

Science.gov (United States)

Manual palpation (MP) is commonly used for the assessment of patients with neuromusculoskeletal dysfunction. During assessment of lumbo-pelvic disorders in particular, it may be used not only to explore pain and resistance in the region, but also to evaluate the symmetry and movement quality of the area. Whilst reliability of MP has been extensively investigated, its validity remains relatively under researched. The aim of this study was to explore the accuracy of MP of lumbo-pelvic bony points. Ultrasound images of three bony landmarks [4th lumbar spinous process (L4), left and right posterior superior iliac spines (PSIS)] were acquired from models (n = 3) in the prone position and the points marked with an ultra-violet (UV) pen. Nine musculoskeletal physiotherapists were asked to identify the bony landmarks using MP. Measurements (mms) were taken between the UV marks and the palpators' marks. The mean error (standard deviation) (mm) for MP of L4, LPSIS, RPSIS were 15.63 (3.89), 20.07 (4.60), 20.59 (2.79) respectively. Bland and Altman analysis gave a mean value of 0.173, with 95% limits of agreement ranging from -27.8 to 26.3. This study suggests that MP of specific lumbo-pelvic bony points has limited validity. PMID:21945296

Kilby, Julia; Heneghan, Nicola R; Maybury, Mark

2012-06-01

313

The Development of Landmark and Beacon Use in Young Children: Evidence from a Touchscreen Search Task  

Science.gov (United States)

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…

Sutton, Jennifer E.

2006-01-01

314

Blocking of Spatial Learning between Enclosure Geometry and a Local Landmark  

Science.gov (United States)

In a virtual environment, blocking of spatial learning to locate an invisible target was found reciprocally between a distinctively shaped enclosure and a local landmark within its walls. The blocking effect was significantly stronger when the shape of the enclosure rather than the landmark served as the blocking cue. However, the extent to which…

Wilson, Paul N.; Alexander, Tim

2008-01-01

315

Landmark Learning in a Navigation Task Is Not Affected by the Female Rats' Estrus Cycle  

Science.gov (United States)

In two experiments rats were required to escape from a circular pool by swimming to an invisible platform that was located in the same place relative to one configuration of two landmarks (X and Y). The two landmarks were placed relatively far and equidistant from the hidden platform. Training could be either on consecutive days (Experiment 1) or…

Rodriguez, Clara A.; Aguilar, Raul; Chamizo, V. D.

2011-01-01

316

On-board landmark navigation and attitude reference parallel processor system  

Science.gov (United States)

An approach to autonomous navigation and attitude reference for earth observing spacecraft is described along with the landmark identification technique based on a sequential similarity detection algorithm (SSDA). Laboratory experiments undertaken to determine if better than one pixel accuracy in registration can be achieved consistent with onboard processor timing and capacity constraints are included. The SSDA is implemented using a multi-microprocessor system including synchronization logic and chip library. The data is processed in parallel stages, effectively reducing the time to match the small known image within a larger image as seen by the onboard image system. Shared memory is incorporated in the system to help communicate intermediate results among microprocessors. The functions include finding mean values and summation of absolute differences over the image search area. The hardware is a low power, compact unit suitable to onboard application with the flexibility to provide for different parameters depending upon the environment.

Gilbert, L. E.; Mahajan, D. T.

1978-01-01

317

Anatomically Plausible Surface Alignment and Reconstruction  

DEFF Research Database (Denmark)

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 combined with a Markov Random Field regularisation method. Conceptually, the method maintains an implicit ideal description of the sought surface. This implicit surface is iteratively updated by realigning the input point sets and Markov Random Field regularisation. The regularisation is based on a prior energy that has earlier proved to be particularly well suited for human surface scans. The method has been tested on full cranial scans of ten test subjects and on several scans of the outer human ear.

Paulsen, Rasmus R.; Larsen, Rasmus

2010-01-01

318

Utilization management in anatomic pathology.  

Science.gov (United States)

There is relatively little published literature concerning utilization management in anatomic pathology. Nonetheless there are many utilization management opportunities that currently exist and are well recognized. Some of these impact only the cost structure within the pathology department itself whereas others reduce charges for third party payers. Utilization management may result in medical legal liabilities for breaching the standard of care. For this reason it will be important for pathology professional societies to develop national utilization guidelines to assist individual practices in implementing a medically sound approach to utilization management. PMID:24140174

Lewandrowski, Kent; Black-Schaffer, Steven

2014-01-01

319

Landmark and route knowledge in children's spatial representation of a virtual environment.  

Science.gov (United States)

This study investigates the development of landmark and route knowledge in complex wayfinding situations. It focuses on how children (aged 6, 8, and 10 years) and young adults (n = 79) indicate, recognize, and bind landmarks and directions in both verbal and visuo-spatial tasks after learning a virtual route. Performance in these tasks is also related to general verbal and visuo-spatial abilities as assessed by independent standardized tests (attention, working memory, perception of direction, production and comprehension of spatial terms, sentences and stories). The results first show that the quantity and quality of landmarks and directions produced and recognized by participants in both verbal and visuo-spatial tasks increased with age. In addition, an increase with age was observed in participants' selection of decisional landmarks (i.e., landmarks associated with a change of direction), as well as in their capacity to bind landmarks and directions. Our results support the view that children first acquire landmark knowledge, then route knowledge, as shown by their late developing ability to bind knowledge of directions and landmarks. Overall, the quality of verbal and visuo-spatial information in participants' spatial representations was found to vary mostly with their visuo-spatial abilities (attention and perception of directions) and not with their verbal abilities. Interestingly, however, when asked to recognize landmarks encountered during the route, participants show an increasing bias with age toward choosing a related landmark of the same category, regardless of its visual characteristics, i.e., they incorrectly choose the picture of another fountain. The discussion highlights the need for further studies to determine more precisely the role of verbal and visuo-spatial knowledge and the nature of how children learn to represent and memorize routes. PMID:25667573

Nys, Marion; Gyselinck, Valérie; Orriols, Eric; Hickmann, Maya

2014-01-01

320

Landmark and route knowledge in children’s spatial representation of a virtual environment  

Science.gov (United States)

This study investigates the development of landmark and route knowledge in complex wayfinding situations. It focuses on how children (aged 6, 8, and 10 years) and young adults (n = 79) indicate, recognize, and bind landmarks and directions in both verbal and visuo-spatial tasks after learning a virtual route. Performance in these tasks is also related to general verbal and visuo-spatial abilities as assessed by independent standardized tests (attention, working memory, perception of direction, production and comprehension of spatial terms, sentences and stories). The results first show that the quantity and quality of landmarks and directions produced and recognized by participants in both verbal and visuo-spatial tasks increased with age. In addition, an increase with age was observed in participants’ selection of decisional landmarks (i.e., landmarks associated with a change of direction), as well as in their capacity to bind landmarks and directions. Our results support the view that children first acquire landmark knowledge, then route knowledge, as shown by their late developing ability to bind knowledge of directions and landmarks. Overall, the quality of verbal and visuo-spatial information in participants’ spatial representations was found to vary mostly with their visuo-spatial abilities (attention and perception of directions) and not with their verbal abilities. Interestingly, however, when asked to recognize landmarks encountered during the route, participants show an increasing bias with age toward choosing a related landmark of the same category, regardless of its visual characteristics, i.e., they incorrectly choose the picture of another fountain. The discussion highlights the need for further studies to determine more precisely the role of verbal and visuo-spatial knowledge and the nature of how children learn to represent and memorize routes. PMID:25667573

Nys, Marion; Gyselinck, Valérie; Orriols, Eric; Hickmann, Maya

2015-01-01

321

Bringing history to life: simulating landmark experiments in psychology.  

Science.gov (United States)

The course in history of psychology can be challenging for students, many of whom enter it with little background in history and faced with unfamiliar names and concepts. The sheer volume of material can encourage passive memorization unless efforts are made to increase student involvement. As part of a trend toward experiential history, historians of science have begun to supplement their lectures with demonstrations of classic physics experiments as a way to bring the history of science to life. Here, the authors report on computer simulations of five landmark experiments from early experimental psychology in the areas of reaction time, span of attention, and apparent motion. The simulations are designed not only to permit hands-on replication of historically important results but also to reproduce the experimental procedures closely enough that students can gain a feel for the nature of early research and the psychological processes being studied. PMID:17152604

Boynton, David M; Smith, Laurence D

2006-05-01

322

A neural wayfinding mechanism adjusts for ambiguous landmark information.  

Science.gov (United States)

Objects along a route can serve as crucial landmarks that facilitate successful navigation. Previous functional magnetic resonance imaging (fMRI) evidence indicated that the human parahippocampal gyrus automatically distinguishes between objects placed at navigationally relevant (decision points) and irrelevant locations (non-decision points). This storage of relevant objects can provide a neural mechanism underlying successful navigation. However, only objects that actually support wayfinding need to be stored. Objects can also provide misleading information if similar objects appear at different locations along a route. An efficient mechanism needs to specifically adjust for ambiguous landmark information. We investigated this by placing identical objects twice in a virtual labyrinth at places with the same as well as with a different navigational relevance. Twenty right-handed volunteers moved through a virtual maze. They viewed the same object either at two different decision points, at two different non-decision points, or at a decision as well as at a non-decision point. Afterwards, event-related fMRI data were acquired during object recognition. Participants decided whether they had seen the objects in the maze or not. The results showed that activity in the parahippocampal gyrus was increased for objects placed at a decision and at a non-decision point as compared to objects placed at two non-decision points. However, ambiguous information resulting from the same object placed at two different decision points revealed increased activity in the right middle frontal gyrus. These findings suggest a neural wayfinding mechanism that differentiates between helpful and misleading information. PMID:20381625

Janzen, Gabriele; Jansen, Clemens

2010-08-01

323

Germ band retraction as a landmark in glucose metabolism during Aedes aegypti embryogenesis  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background The mosquito A. aegypti is vector of dengue and other viruses. New methods of vector control are needed and can be achieved by a better understanding of the life cycle of this insect. Embryogenesis is a part of A. aegypty life cycle that is poorly understood. In insects in general and in mosquitoes in particular energetic metabolism is well studied during oogenesis, when the oocyte exhibits fast growth, accumulating carbohydrates, lipids and proteins that will meet the regulatory and metabolic needs of the developing embryo. On the other hand, events related with energetic metabolism during A. aegypti embryogenesis are unknown. Results Glucose metabolism was investigated throughout Aedes aegypti (Diptera embryonic development. Both cellular blastoderm formation (CBf, 5 h after egg laying - HAE and germ band retraction (GBr, 24 HAE may be considered landmarks regarding glucose 6-phosphate (G6P destination. We observed high levels of glucose 6-phosphate dehydrogenase (G6PDH activity at the very beginning of embryogenesis, which nevertheless decreased up to 5 HAE. This activity is correlated with the need for nucleotide precursors generated by the pentose phosphate pathway (PPP, of which G6PDH is the key enzyme. We suggest the synchronism of egg metabolism with carbohydrate distribution based on the decreasing levels of phosphoenolpyruvate carboxykinase (PEPCK activity and on the elevation observed in protein content up to 24 HAE. Concomitantly, increasing levels of hexokinase (HK and pyruvate kinase (PK activity were observed, and PEPCK reached a peak around 48 HAE. Glycogen synthase kinase (GSK3 activity was also monitored and shown to be inversely correlated with glycogen distribution during embryogenesis. Conclusions The results herein support the hypothesis that glucose metabolic fate changes according to developmental embryonic stages. Germ band retraction is a moment that was characterized as a landmark in glucose metabolism during Aedes aegypti embryogenesis. Furthermore, the results also suggest a role for GSK3 in glycogen balance/distribution during morphological modifications.

Logullo Carlos

2010-02-01

324

Model-independent, multimodality deformable image registration by local matching of anatomical features and minimization of elastic energy.  

Science.gov (United States)

With respect to the demands of adaptive and 4D-radiotherapy applications, an algorithm is proposed for a fully automatic, multimodality deformable registration that follows the concept of translational relocation of regularly distributed image subvolumes governed by local anatomical features. Thereby, the problem of global deformable registration is broken down to multiple independent local registration steps which allows for straightforward parallelization of the algorithm. In a subsequent step, possible local misregistrations are corrected for by minimization of the elastic energy of the displacement field under consideration of image information. The final displacement field results from interpolation of the subvolume shift vectors. The algorithm can employ as a similarity measure both the correlation coefficient and mutual information. The latter allows the application to intermodality deformable registration problems. The typical calculation time on a modern multiprocessor PC is well below 1 min, which facilitates almost-interactive, "online" usage. CT-to-MRI and CT-to-cone-beam-CT registrations of head-and-neck data sets are presented, as well as inhale-to-exhale registrations of lung CT data sets. For quantitative evaluation of registration accuracy, a virtual thorax phantom was developed; additionally, a landmark-based evaluation on four lung respiratory-correlated CT data sets was performed. This consistently resulted in average registration residuals on the order of the voxel size or less (3D-residuals approximately 1-2 mm). Summarizing, the presented algorithm allows an accurate multimodality deformable registration with calculation times well below 1 min, and thus bears promise as a versatile basic tool in adaptive and 4D-radiotherapy applications. PMID:18404923

Söhn, Matthias; Birkner, Mattias; Chi, Yuwei; Wang, Jian; Di, Yan; Berger, Bernhard; Alber, Markus

2008-03-01

325

Is there consistency in cephalometric landmark identification amongst oral and maxillofacial surgeons?  

Science.gov (United States)

There may be significant variation amongst oral and maxillofacial surgeons (OMFS) in the identification and placement of cephalometric landmarks for orthognathic surgery, and this could impact upon the surgical plan and final treatment outcome. In an effort to assess this variability, 10 lateral cephalometric radiographs were selected for evaluation by 16 OMFS with different levels of surgical knowledge and experience, and the position of 21 commonly used cephalometric landmarks were identified on radiographs displayed on a computer screen using a computer mouse on a pen tablet. The database consisted of real position measurements (x, y) to determine the consistency of landmark identification between surgeons and within individual surgeons. Inter-examiner analysis demonstrated that most landmark points had excellent reliability (intra-class correlation coefficient >0.90). Regardless of the level of surgeon experience, certain landmarks presented consistently poor reliability, and intra-examiner reliability analysis demonstrated that some locations had a higher average difference for both x and y axes. In particular, porion, condylion, and gonion showed poor agreement and reliability between examiners. The identification of most landmarks showed some inconsistencies within different parameters of evaluation. Such variability among surgeons may be addressed by the consistent use of high-quality images, and also by periodic surgeon education of the definition of the specific landmarks. PMID:24055177

Miloro, M; Borba, A M; Ribeiro-Junior, O; Naclério-Homem, M G; Jungner, M

2014-04-01

326

An anatomical and functional topography of human auditory cortical areas  

Directory of Open Access Journals (Sweden)

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.

EliaFormisano

2014-07-01

327

Anatomical correlations of the international 10-20 sensor placement system in infants.  

Science.gov (United States)

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

Kabdebon, C; Leroy, F; Simmonet, H; Perrot, M; Dubois, J; Dehaene-Lambertz, G

2014-10-01

328

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 deimaged 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)

329

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)

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)

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

330

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 backgroundirmed 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)

331

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)

Full Text Available SciELO Brazil | Languages: English, Portuguese Abstract in portuguese 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.

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

332

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  

Science.gov (United States)

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).

Pain, F.; Dhenain, M.; Gurden, H.; Routier, A. L.; Lefebvre, F.; Mastrippolito, R.; Lanièce, P.

2008-10-01

333

Diffusion of innovations: anatomical informatics and iPods.  

Science.gov (United States)

Over the course of many centuries, evolving scientific methods and technologies have advanced the study of anatomy. More recently, such dissemination of innovations has been formally studied in multidisciplinary psychosocial contexts, yielding useful knowledge about underlying principles and processes. We review these precepts and show how diffusion of innovations theory and principles apply to the development and dissemination of anatomical information methods and resources. We consider the factors affecting the late-20th-century dissemination of personal computers and World Wide Web hypermedia into widespread use in anatomical research and instruction. We report on the results of a small experiment in applied diffusion, the development and Internet-based distribution of learning resources for a popular, widely distributed personal media player. With these wearable microcomputer devices already in use by a variety of students, new opportunities exist for widespread dissemination of anatomical information. The continuing evolution of wearable computing devices underscores the need for maintaining anatomical information transportability via standardized data formats. PMID:16955498

Trelease, Robert B

2006-09-01

334

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

335

Ethmomaxillary sinus: a particular anatomic variation of the paranasal sinuses  

Energy Technology Data Exchange (ETDEWEB)

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.)

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

336

The relative importance of global and local landmarks in navigation by Columbian ground squirrels (Spermophilus columbianus).  

Science.gov (United States)

In order to survive, small burrowing mammals need to remember the locations of escape burrows. Therefore, it is important to know what types of landmarks are used to aid navigation in the wild. The author tested the ability of free-ranging Columbian ground squirrels (Spermophilus columbianus) to locate escape burrows when local (e.g., vegetation pattern, local relief), global (e.g., forest edge, mountain outline), or both types of landmarks were obstructed. Results suggest that squirrels need both local and global landmarks of the environment for successful navigation, and that the upper portion of the horizon is especially important for orientation. Moreover, the lack of information from one type of landmark (local or global) cannot be completely compensated by the other type. PMID:16719591

Vlasak, Anna N

2006-05-01

337

77 FR 44670 - Information Collection Activities: National Historic Landmarks (NHL) Condition Survey  

Science.gov (United States)

...collect information regarding the condition of designated landmarks. A...owners or other stewards so the condition of NHLs can be monitored over time. The regional offices...assist in the collection of the condition data. Regional NPS staff...

2012-07-30

338

78 FR 49975 - Energy Conservation Program for Consumer Products: Landmark Legal Foundation; Petition for...  

Science.gov (United States)

...EERE-BT-PET-0043] Energy Conservation Program for Consumer Products: Landmark Legal Foundation...energy conservation standards for various consumer products and certain commercial and industrial...the opportunity to comment on DOE's motivations, methodologies and conclusions in...

2013-08-16

339

Clinically relevant landmarks of the frontotemporal branch of the facial nerve: a three-dimensional study.  

Science.gov (United States)

The frontotemporal branch of the facial nerve (FTN) is vulnerable during craniofacial surgeries due to its superficial course and variable distribution. Surface landmarks that correlate with the underlying course of the FTN can assist in surgical planning. Estimates of the course of FTN commonly rely on Pitanguy's line (PL), which utilizes variable soft-tissue landmarks. The purpose of this study was to evaluate palpable surface landmarks to predict the course and distribution of FTN using 3D modeling. Fifteen half-heads were used. In five formalin-embalmed specimens, surface topography was obtained using a FARO® scanner and landmarks corresponding to PL, porion, supraorbital notch, frontozygomatic and zygomaticotemporal sutures, and supraorbitomeatal line (SOML) and infraorbitomeatal line (IOML) were demarcated/digitized using a Microscribe™ digitizer. A preauricular flap was raised, and branches of FTN were isolated and digitized. The data were reconstructed into 3D models (Geomagic®/Maya®) to quantify landmarks. In 10 Thiel-embalmed specimens, four independent raters identified/palpated and pinned the frontozygomatic and zygomaticotemporal sutures and PL. Data were collected and analyzed using the same protocol as in the first part of the study. Landmarking of PL was inconsistent between raters and not representative of FTN distribution. The easily identifiable surface landmarks defined in this study, a line 12 mm anterior to the porion along the SOML and IOML and a line joining the zygomaticotemporal and frontozygomatic sutures, comprehensively captured the distribution of FTN. The raters found a mean of 21 ± 2 branches between the lines out of a total of 22 ± 2 branches. These landmarks may be used clinically to avoid injury to FTN. PMID:22991167

Davies, Joel C; Fattah, Adel; Ravichandiran, Mayoorendra; Agur, Anne M

2012-10-01

340

Learning Compact Visual Descriptors for Low Bit Rate Mobile Landmark Search  

OpenAIRE

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...

Duan, Ling-yu Peking University; Chen, Jie Peking University; Ji, Rongrong Peking University; Huang, Tiejun Peking University; Gao, Wen Peking University

2013-01-01

341

Assessment of the reliability and repeatability of landmarks using 3-D cephalometry software.  

OpenAIRE

The aim of this study was to analyze the reliability and repeatability of identification landmarks using 3-D cephalometric software. Ten orthognathic patients were selected for this study and underwent the following protocol: 1. radiographic evaluation (CBCT technique); 2. stone casts; 3. photos; and 4. 3-D cephalometric evaluation. Twenty-one hard tissue landmarks and 14 cephalometric measurements were taken three times (T1, T2, and T3) on each patient, with an interval of one week by two ex...

Frongia, Gianluigi; Piancino, Maria Grazia; Bracco, Pietro

2012-01-01

342

Further evidence for visual landmark involvement in the pigeon's familiar area map  

OpenAIRE

In previous experiments suggesting that previewing visual landscapes speeds homing from familiar release sites, restricted access to olfactory cues may have artefactually encouraged homing pigeons, Columba liviato resort to visual landmark orientation. Since evidence for the role of visual landmarks in wide-ranging avian orientation is still equivocal, Braithwaite and Guilford's (1991, Proc. R. Soc. Lond. Ser. B245, 183-186) 'previewing' experiments were replicated: birds were allowed or deni...

Burt, T.; Holland, R.; Guilford, T.

1997-01-01

343

Sequential egocentric navigation and reliance on landmarks in Williams syndrome and typical development.  

Science.gov (United States)

Visuospatial difficulties in Williams syndrome (WS) are well documented. Recently, research has shown that spatial difficulties in WS extend to large-scale space, particularly in coding space using an allocentric frame of reference. Typically developing (TD) children and adults predominantly rely on the use of a sequential egocentric strategy to navigate a large-scale route (retracing a sequence of left-right body turns). The aim of this study was to examine whether individuals with WS are able to employ a sequential egocentric strategy to guide learning and the retracing of a route. Forty-eight TD children, aged 5, 7, and 9 years and 18 participants with WS were examined on their ability to learn and retrace routes in two (6-turn) virtual environment mazes (with and without landmarks). The ability to successfully retrace a route following the removal of landmarks (use of sequential egocentric coding) was also examined. Although in line with TD 5-year-olds when learning a route with landmarks, individuals with WS showed significantly greater detriment when these landmarks were removed, relative to all TD groups. Moreover, the WS group made significantly more errors than all TD groups when learning a route that never contained landmarks. On a perceptual view-matching task, results revealed a high level of performance across groups, indicative of an ability to use this visual information to potentially aid navigation. These findings suggest that individuals with WS rely on landmarks to a greater extent than TD children, both for learning a route and for retracing a recently learned route. TD children, but not individuals with WS, were able to fall back on the use of a sequential egocentric strategy to navigate when landmarks were not present. Only TD children therefore coded sequential route information simultaneously with landmark information. The results are discussed in relation to known atypical cortical development and perceptual-matching abilities in WS. PMID:25762973

Broadbent, Hannah J; Farran, Emily K; Tolmie, Andrew

2015-01-01

344

Deficits in Landmark Navigation and Path Integration after Lesions of the Interpeduncular Nucleus  

OpenAIRE

Experiments were designed to determine the role of the interpeduncular nucleus (IPN) in three forms of navigation: beacon, landmark, and path integration. In beacon navigation, animals reach goals using cues directly associated with them, whereas in landmark navigation animals use external cues to determine a direction and distance to goals. Path integration refers to the use of self-movement cues to obtain a trajectory to a goal. IPN-lesioned rats were tested in a food-carrying task where th...

Clark, Benjamin J.; Taube, Jeffrey S.

2009-01-01

345

ANATOMIC VARIATIONS OF PARANASAL SINUSES IN PATIENTS WITH CHRONIC SINUSITIS AND THEIR CORRELATION WITH CT SCAN STAGING  

OpenAIRE

The presence of anatomic variations of paranasal sinuses must be noted in order to attain a full understanding and accurate diagnosis of chronic sinusitis. The frequency of anatomic variations in chronic sinusitis is different in various studies. The purpose of this study is to assess the frequency of anatomic variations in chronic sinusitis patients admitted to Otolaryngology ward of Shahid Sadoughi hospital in the year 2004 and underwent functional endoscopic sinus surgery. Based on preoper...

Baradaranfar, M. H.; Labibi, M.

2007-01-01

346

Generalized metrics induced anatomical prior for MAP PET image reconstruction  

International Nuclear Information System (INIS)

Information theoretic metrics, including mutual information (MI) and joint entropy (JE), have been investigated as priors to incorporate anatomical information in ill-posed positron emission tomography (PET) image reconstruction. These metrics are generally based on the Shannon entropy. Meanwhile, in this paper, we proposed a generalized metrics induced anatomical prior for maximum a posteriori (MAP) PET reconstruction based on the generalized Shannon entropy metrics or Tsallis entropy. For the presented prior computation, a non-parametric method was used to estimate the joint probability density of the PET and MR image. Furthermore, we also developed an one-step-advance (OSA) MAP algorithm for PET image reconstruction with the presented prior regularization. Simulation results show that the presented novel prior has significantly improved the reconstructed PET image quality. (orig.)

347

Analysis of anatomic variability in children with low mathematical skills  

Science.gov (United States)

Mathematical difficulty affects approximately 5-9% of the population. Studies on individuals with dyscalculia, a neurologically based math disorder, provide important insight into the neural correlates of mathematical ability. For example, cognitive theories, neuropsychological studies, and functional neuroimaging studies in individuals with dyscalculia suggest that the bilateral parietal lobes and intraparietal sulcus are central to mathematical performance. The purpose of the present study was to investigate morphological differences in a group of third grade children with poor math skills. We compare population averages of children with low math skill (MD) to gender and age matched controls with average math ability. Anatomical data were gathered with high resolution MRI and four different population averaging methods were used to study the effect of the normalization technique on the results. Statistical results based on the deformation fields between the two groups show anatomical differences in the bilateral parietal lobes, right frontal lobe, and left occipital/parietal lobe.

Han, Zhaoying; Fuchs, Lynn; Davis, Nikki; Cannistraci, Christopher J.; Anderson, Adam W.; Gore, John C.; Dawant, Benoit M.

2008-03-01

348

[The anatomical revolution and the transition of anatomical conception in late imperial china].  

Science.gov (United States)

This paper aimed to examine the anatomical revolution from Yilingaicuo (Correcting the Errors of Medicine) and Quantixinlun(Outline of Anatomy and Physiology) in late imperial China. As the cephalocentrism which the brain superintend human operation of the mind was diffused in China since 16th century, the cephalocentrism and the cardiocentrism had competed for the hegemony of anatomical conception. Because of the advent of Yilingaicuo and Quantixinlun, the cephalocentrism became the main stream in the anatomical conception. The supporters of the Wang Yangming's Xinxue(the Learning of Heart and Mind) argued that the heart was the central organ of perception, sensitivity, and morality of the human body in medicine since 16th century. Even reformist and revolutionary intellectuals like Tan sitong and Mao zedong who had supported the Wang Yangming's Xinxue embraced the cephalocentrism in the late 19th century and the early 20th century. May Fourth intellectuals had not obsessed metaphysical interpretation of human body any more in the New Culture Movement in 1910s. They regarded human body as the object of research and writing. The anatomy was transformed into the instrumental knowledge for mutilation of the body. Yilingaicuo challenged the traditional conception of body, and Chinese intellectuals drew interest in the anatomy knowledge based on real mutilation. Quantixinlun based on Western medicine fueled a controversy about anatomy. Though new knowledge of anatomy was criticized by traditional Chinese medical doctors from the usefulness and morality of anatomy, nobody disavowed new knowledge of anatomy from the institutionalization of Western medicine in medical school. The internal development of cephalocentrism and positivism had influence on anatomy in China since 16th century. The advent of Yilingaicuo and Quantixinlun provided the milestone of new anatomy, though both sides represented traditional Chinese medicine and Western medicine respectively. They contributed to the development of new knowledge of anatomy, getting over the metaphysical system of knowledge. Based on the internal development of anatomy, Chinese anatomy was half century late than Japanese anatomy founded on Dutch anatomy. PMID:22739627

Sihn, Kyu Hwan

2012-04-30

349

Multivariate models of inter-subject anatomical variability  

OpenAIRE

This paper presents a very selective review of some of the approaches for multivariate modelling of intersubject variability among brain images. It focusses on applying probabilistic kernel-based pattern recognition approaches to pre-processed anatomical MRI, with the aim of most accurately modelling the difference between populations of subjects. Some of the principles underlying the pattern recognition approaches of Gaussian process classification and regression are briefly described, altho...

Ashburner, J.; Kloppel, S.

2011-01-01

350

The aspects regarding Chrysanthemum vitro- and exvitroplantlets anatomical structure  

Directory of Open Access Journals (Sweden)

Full Text Available This study was consecrate to observe the histoanatomical structure of roots stems and leafs of Chrysanthemum vitroplantlets, in their vitroculture period and of exvitroplantlets, at 30 days from their septic medium transfer. The registered observations were compared with those realized at similar organs level of greenhouse plants (control lot. The noted differences between vitroplantlets anatomical structure and that greenhouse plants had, in special, ontogenetic bases.

Adriana PETRUS-VANCEA

2007-05-01

351

Effect of temperature on six different developmental landmarks within the pupal stage of the forensically important blowfly Calliphora vicina (Robineau-Desvoidy) (Diptera: Calliphoridae).  

Science.gov (United States)

This study investigates the pupal development times of the blow fly Calliphora vicina, which were studied in the laboratory at six different constant temperatures (15, 20, 23, 25, 28, and 30°C each ± 1°C). Lower thresholds (tL ) for development were estimated from the linear regression of the developmental rates on each temperature. These data have made it possible to calculate the accumulated degree days (ADD) necessary for C. vicina to complete the larval stage and to achieve adult emergence. The minimal duration of development from oviposition to adult emergence was found to be inversely related to temperature. Additionally, six landmarks in pupal development are showed, and for each of the landmarks, the ADD value was calculated for every rearing temperature involved. These data assist in calculating the duration of the pupal stage based on morphological characteristics and would be of great value for future forensic entomological casework. PMID:23899305

Defilippo, Francesco; Bonilauri, Paolo; Dottori, Michele

2013-11-01

352

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

Energy Technology Data Exchange (ETDEWEB)

{sup 18}F FP CIT positron emission tomography (PET) is an effective imaging for dopamine transporters. In usual clinical practice, {sup 18}F 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 {sup 18}F 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, Q{sup SPAM,} 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(Q{sup UVP)} was calculated for each striatal region. Q{sup SPAMa}nd Q{sup UVPw}as 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 Q{sup SPAMa}nd Q{sup UVPw}ere significantly different according to visual grading (0.001). The agreements of Q{sup UVPa}nd Q{sup SPAMw}ith 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, Q{sup SPAMa}nd Q{sup UVPh}ad a significant correlation with each other (0.001). Cerebral atrophy made a significant difference in Q{sup SPAMa}nd Q{sup UVPo}f the caudate nuclei regions with decreased {sup 18}F FP CIT uptake. Simple quantitative measurements of Q{sup SPAMa}nd Q{sup UVPs}howed acceptable agreement with visual grad-ing. although Q{sup SPAMi}n 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.

Kim, Yong Il; Im, Hyung Jun; Paeng, Jin Chul; Lee, Jae Sung; Eo, Jae Seon; Kim, Dong Hyun; Kim, Euishin E.; Kang, Keon Wook; Chung, June Key; Lee Dong Soo [Seoul National Univ. Hospital, Seoul (Korea, Republic of)

2012-12-15

353

Estimativas da composição anatômica da carcaça de frangos de corte com base no nível de proteína da ração e peso da carcaça Estimation of the carcasses anatomical composition of broiler from diet quality and carcass weight  

Directory of Open Access Journals (Sweden)

Full Text Available Um experimento foi desenvolvido com o objetivo de estimar as proporções dos cortes nobres da carcaça de frangos de corte pelo modelo linear. Foram utilizados 842 frangos machos da linhagem Avian Farms, de 22 a 42 dias de idade, distribuídos num delineamento inteiramente ao acaso em esquema fatorial 3x4. Foram fornecidas rações formuladas à base de milho e farelo de soja para conter 2.900 kcal de EM e 15,43; 17,26; 19,60; e 22,60% de PB; 3.100 kcal de EM e 16,49; 18,45; 20,95; e 24,22% de PB; e 3300 kcal de EM e 17,55; 19,64; 22,30; e 25,78% de PB, totalizando doze tratamentos. Cada tratamento foi constituído por quatro repetições de 18 aves. Fortes correlações foram observadas entre o peso vivo aos 42 dias e o peso da carcaça (r = 0,958, o peso da carcaça e o peso de pernas (r = 0,991, peso de peito+osso+pele (r = 0,965 e peso de peito desossado (r = 0,950. A porcentagem de lipídio foi negativamente correlacionada com a porcentagem de umidade da carcaça (r = -0,880. A equação linear é recomendada para a predição dos componentes anatômicos da carcaça de frangos de corte.An experiment was carried out to estimate the relations between broiler carcass weight and thighs+drumsticks, breast+bone+skin, and breast meat by the linear model. Eight hundred and sixty and four male poultry of Arbor Acres strain, from 22 to 42 days of age, were assigned to a completely randomized design in 3x4factorial scheme. Corn and soybean meal based diets were prepared to contain 2900 kcal ME and 15.43; 17.26; 19.60; and 22.60% CP; 3,100 kcal ME and 16.49; 18.45; 20.95; and 24.22%CP; and 3300 kcal ME and 17.55; 19.64; 22.30; and 25.78% CP, resulting in twelve treatments. Each treatment was constituted of four replicates of 18 birds. High correlations were observed between live weight at 42 days old and carcass weight (r = 0.958, carcass weight and thighs+drumsticks (r = 0.991, breast+bone+skin (r = 0.965 and deboned breast meat weight (r = 0.950. The lipid percentage was negatively correlated to the moisture percentage (r = -0.880. The linear equation is recommended to estimate carcass anatomical components in broiler chickens.

José Humberto Vilar da Silva

2003-04-01

354

Morphological and anatomical studies of Cyani herba  

Directory of Open Access Journals (Sweden)

Full Text Available Morphological and anatomical investigation were carried out on stem, leaves, flowers and bracts of the species Centaurea cyanusL. The diagnostic parameters of vegetal product Cyani herbawere defined.

Tatiana Chiru

2013-04-01

355

Anatomical basis for Wilms tumor surgery  

OpenAIRE

Wilms tumor surgery requires meticulous planning and sophisticated surgical technique. Detailed anatomical knowledge can facilitate the uneventful performance of tumor nephrectomy and cannot be replaced by advanced and sophisticated imaging techniques. We can define two main goals for surgery: (1) exact staging as well as (2) safe and complete resection of tumor without spillage. This review aims to review the anatomical basis for Wilms tumor surgery. It focuses on the surgical anatomy of ret...

Trobs R

2009-01-01

356

Introducing International Journal of Anatomical Variations  

OpenAIRE

Welcome to International Journal of Anatomical Variations (IJAV) - an annual journal of anatomical variations and clinical anatomy case reports. After having a notable experience for eight years in NEUROANATOMY, we are pleased to introduce you IJAV. We are eventually announcing our new journal after three years of feasibility and background study period. We hope that IJAV will fill in the gap in anatomy journals’ bunch. IJAV is an annual, open access journal having electronic version only. ...

Tunali S

2008-01-01

357

Engineering anatomically shaped human bone grafts  

OpenAIRE

The ability to engineer anatomically correct pieces of viable and functional human bone would have tremendous potential for bone reconstructions after congenital defects, cancer resections, and trauma. We report that clinically sized, anatomically shaped, viable human bone grafts can be engineered by using human mesenchymal stem cells (hMSCs) and a “biomimetic” scaffold-bioreactor system. We selected the temporomandibular joint (TMJ) condylar bone as our tissue model, because of its clini...

Grayson, Warren L.; Fro?hlich, Mirjam; Yeager, Keith; Bhumiratana, Sarindr; Chan, M. Ete; Cannizzaro, Christopher; Wan, Leo Q.; Liu, X. Sherry; Guo, X. Edward; Vunjak-novakovic, Gordana

2009-01-01

358

3-D Facial Landmark Localization With Asymmetry Patterns and Shape Regression from Incomplete Local Features.  

Science.gov (United States)

We present a method for the automatic localization of facial landmarks that integrates nonrigid deformation with the ability to handle missing points. The algorithm generates sets of candidate locations from feature detectors and performs combinatorial search constrained by a flexible shape model. A key assumption of our approach is that for some landmarks there might not be an accurate candidate in the input set. This is tackled by detecting partial subsets of landmarks and inferring those that are missing, so that the probability of the flexible model is maximized. The ability of the model to work with incomplete information makes it possible to limit the number of candidates that need to be retained, drastically reducing the number of combinations to be tested with respect to the alternative of trying to always detect the complete set of landmarks. We demonstrate the accuracy of the proposed method in the face recognition grand challenge database, where we obtain average errors of approximately 3.5 mm when targeting 14 prominent facial landmarks. For the majority of these our method produces the most accurate results reported to date in this database. Handling of occlusions and surfaces with missing parts is demonstrated with tests on the Bosphorus database, where we achieve an overall error of 4.81 and 4.25 mm for data with and without occlusions, respectively. To investigate potential limits in the accuracy that could be reached, we also report experiments on a database of 144 facial scans acquired in the context of clinical research, with manual annotations performed by experts, where we obtain an overall error of 2.3 mm, with averages per landmark below 3.4 mm for all 14 targeted points and within 2 mm for half of them. The coordinates of automatically located landmarks are made available on-line. PMID:25314716

Sukno, Federico M; Waddington, John L; Whelan, Paul F

2014-10-01

359

Anatomical correlates of foreign speech sound production.  

Science.gov (United States)

Previous work has shown a relationship between brain anatomy and how quickly adults learn to perceive foreign speech sounds. Faster learners have greater asymmetry (left>right) in parietal lobe white matter (WM) volumes and larger WM volumes of left Heschl's gyrus than slower learners. Here, we tested native French speakers who were previously scanned using high-resolution anatomical magnetic resonance imaging. We asked them to pronounce a Persian consonant that does not exist in French but which can easily be distinguished from French speech sounds, the voiced uvular stop. Two judges scored the goodness of the utterances. Voxel-based morphometry revealed that individuals who more accurately pronounce the foreign sound have higher WM density in the left insula/prefrontal cortex and in the inferior parietal cortices bilaterally compared with poorer producers. Results suggest that WM anatomy in brain regions previously implicated in articulation and phonological working memory, or the size/shape of these or adjacent regions, is in part predictive of the accuracy of speech sound pronunciation. PMID:16740583

Golestani, Narly; Pallier, Christophe

2007-04-01

360

Visual attention-based robot self-localization  

OpenAIRE

This paper reports a landmark-based localization method relying on visual attention. In a learning phase, the multi-cue, multi-scale saliency-based model of visual attention is used to automatically acquire robust visual landmarks that are integrated into a topological map of the navigation environment. During navigation, the same visual attention model detects the most salient visual features that are then matched to the learned landmarks. The matching result yields a probabilistic measure o...

Ouerhani, Nabil; Bur, Alexandre; Hu?gli, Heinz

2005-01-01

361

Anatomical models for space radiation applications: An overview  

Science.gov (United States)

Extremely detailed computerized anatomical male (CAM) and female (CAF) models that have been developed for use in space radiation analyses are discussed and reviewed. Recognizing that the level of detail may currently be inadequate for certain radiological applications, one of the purposes of this paper is to elicit specific model improvements or requirements from the scientific user-community. Methods and rationale are presented which describe the approach used in the Space Shuttle program to extrapolate dosimetry measurements (skin doses) to realistic astronaut body organ doses. Several mission scenarios are presented which demonstrate the utility of the anatomical models for obtaining specific body organ exposure estimates and can be used for establishing cancer morbidity and mortality risk assessments. These exposure estimates are based on the trapped Van Allen belt and galactic cosmic radiation environment models and data from the major historical solar particle events.

Atwell, W.

1994-10-01

362

The early history of keratoconus prior to Nottingham's landmark 1854 treatise on conical cornea: a review.  

Science.gov (United States)

In an era of scientific method, precision of nomenclature and an electronically accessible publication record, the early history of keratoconus still remains, in parts, as complex and perplexing as the disease itself. Historically, the disease has been somewhat confusingly referred to by several different terms, including hyperkeratosis, ochlodes, conical formed cornea, cornea conica, cornée conique, sugar loaf cornea, prolapses corneae, procidentia corneae, staphyloma transparent de la cornée, staphyloma pellucidum, staphyloma corneae totale conicum pellucidum, staphyloma diaphanum, keratconus and keratoconus. In his major 1854 treatise on conical cornea, John Nottingham is widely cited as the first author to succinctly define keratoconus and its associations; however, for 150 years prior to this landmark publication, others had been slowly deciphering elements of keratoconus and distilling their knowledge in a series of publications obscured by the passage of years. Uncritical re-writing of core information and references without their full verification has also led to confusion in the published literature in the 150 years since Nottingham's comprehensive description of keratoconus. In the light of the preceding limitations in the established literature, the authors conducted an historical survey, based on the analysis of original sources, to more fully establish the chronology of early descriptions of keratoconus prior to 1854, with particular focus on the works of Duddell, Taylor, Mauchart, Scarpa, Wardrop, Lyall, MacKenzie, Lawrence, Schmidt, von Ammon and Pickford. This review attempts to place the observations of these practitioners and others both in the context of contemporary ophthalmic practice and historical precedent. PMID:23414219

Grzybowski, Andrzej; McGhee, Charles N J

2013-03-01

363

Indexing Anatomical Phrases in Neuro-Radiology Reports to the UMLS 2005AA  

OpenAIRE

This work describes a methodology to index anatomical phrases to the 2005AA release of the Unified Medical Language System (UMLS). A phrase chunking tool based on Natural Language Processing (NLP) was developed to identify semantically coherent phrases within medical reports. Using this phrase chunker, a set of 2,551 unique anatomical phrases was extracted from brain radiology reports. These phrases were mapped to the 2005AA release of the UMLS using a vector space model. Pr...

Bashyam, Vijayaraghavan; Taira, Ricky K.

2005-01-01

364

Anatomical and functional perspectives of the cervical spine: Part III: the “unstable” cervical spine †  

OpenAIRE

In this, the last of the three part series on the anatomical and functional perspectives of the cervical spine, the clinical entity-instability-is addressed. A summative definition of instability, addressing both the clinical and radiographic issues, is presented based on current available literature. The etiology of instability is discussed as it pertains to three possible mechanisms: acute trauma, latent evidence of trauma and repetitive microtrauma. The anatomical, clinical and radiographi...

Mcgregor, Marion

1990-01-01

365

Comparative Validity and Reproducibility Study of Various Landmark-Oriented Reference Planes in 3-Dimensional Computed Tomographic Analysis for Patients Receiving Orthognathic Surgery  

Science.gov (United States)

Background Three-dimensional computed tomographic imaging has become popular in clinical evaluation, treatment planning, surgical simulation, and outcome assessment for maxillofacial intervention. The purposes of this study were to investigate whether there is any correlation among landmark-based horizontal reference planes and to validate the reproducibility and reliability of landmark identification. Materials and Methods Preoperative and postoperative cone-beam computed tomographic images of patients who had undergone orthognathic surgery were collected. Landmark-oriented reference planes including the Frankfort horizontal plane (FHP) and the lateral semicircular canal plane (LSP) were established. Four FHPs were defined by selecting 3 points from the orbitale, porion, or midpoint of paired points. The LSP passed through both the lateral semicircular canal points and nasion. The distances between the maxillary or mandibular teeth and the reference planes were measured, and the differences between the 2 sides were calculated and compared. The precision in locating the landmarks was evaluated by performing repeated tests, and the intraobserver reproducibility and interobserver reliability were assessed. Results A total of 30 patients with facial deformity and malocclusion—10 patients with facial symmetry, 10 patients with facial asymmetry, and 10 patients with cleft lip and palate—were recruited. Comparing the differences among the 5 reference planes showed no statistically significant difference among all patient groups. Regarding intraobserver reproducibility, the mean differences in the 3 coordinates varied from 0 to 0.35 mm, with correlation coefficients between 0.96 and 1.0, showing high correlation between repeated tests. Regarding interobserver reliability, the mean differences among the 3 coordinates varied from 0 to 0.47 mm, with correlation coefficients between 0.88 and 1.0, exhibiting high correlation between the different examiners. Conclusions The 5 horizontal reference planes were reliable and comparable for 3D craniomaxillofacial analysis. These reference planes were useful in standardizing the orientation of 3D skull models. PMID:25668209

Lin, Hsiu-Hsia; Chuang, Ya-Fang; Weng, Jing-Ling; Lo, Lun-Jou

2015-01-01

366

Visual landmark information gains control of the head direction signal at the lateral mammillary nuclei.  

Science.gov (United States)

The neural representation of directional heading is conveyed by head direction (HD) cells located in an ascending circuit that includes projections from the lateral mammillary nuclei (LMN) to the anterodorsal thalamus (ADN) to the postsubiculum (PoS). The PoS provides return projections to LMN and ADN and is responsible for the landmark control of HD cells in ADN. However, the functional role of the PoS projection to LMN has not been tested. The present study recorded HD cells from LMN after bilateral PoS lesions to determine whether the PoS provides landmark control to LMN HD cells. After the lesion and implantation of electrodes, HD cell activity was recorded while rats navigated within a cylindrical arena containing a single visual landmark or while they navigated between familiar and novel arenas of a dual-chamber apparatus. PoS lesions disrupted the landmark control of HD cells and also disrupted the stability of the preferred firing direction of the cells in darkness. Furthermore, PoS lesions impaired the stable HD cell representation maintained by path integration mechanisms when the rat walked between familiar and novel arenas. These results suggest that visual information first gains control of the HD cell signal in the LMN, presumably via the direct PoS ? LMN projection. This visual landmark information then controls HD cells throughout the HD cell circuit. PMID:25632114

Yoder, Ryan M; Peck, James R; Taube, Jeffrey S

2015-01-28

367

Anatomical accuracy of brain connections derived from diffusion MRI tractography is inherently limited.  

Science.gov (United States)

Tractography based on diffusion-weighted MRI (DWI) is widely used for mapping the structural connections of the human brain. Its accuracy is known to be limited by technical factors affecting in vivo data acquisition, such as noise, artifacts, and data undersampling resulting from scan time constraints. It generally is assumed that improvements in data quality and implementation of sophisticated tractography methods will lead to increasingly accurate maps of human anatomical connections. However, assessing the anatomical accuracy of DWI tractography is difficult because of the lack of independent knowledge of the true anatomical connections in humans. Here we investigate the future prospects of DWI-based connectional imaging by applying advanced tractography methods to an ex vivo DWI dataset of the macaque brain. The results of different tractography methods were compared with maps of known axonal projections from previous tracer studies in the macaque. Despite the exceptional quality of the DWI data, none of the methods demonstrated high anatomical accuracy. The methods that showed the highest sensitivity showed the lowest specificity, and vice versa. Additionally, anatomical accuracy was highly dependent upon parameters of the tractography algorithm, with different optimal values for mapping different pathways. These results suggest that there is an inherent limitation in determining long-range anatomical projections based on voxel-averaged estimates of local fiber orientation obtained from DWI data that is unlikely to be overcome by improvements in data acquisition and analysis alone. PMID:25368179

Thomas, Cibu; Ye, Frank Q; Irfanoglu, M Okan; Modi, Pooja; Saleem, Kadharbatcha S; Leopold, David A; Pierpaoli, Carlo

2014-11-18

368

The language of landmarks: the role of background knowledge in indoor wayfinding.  

Science.gov (United States)

To effectively wayfind through unfamiliar buildings, humans infer their relative position to target locations not only by interpreting geometric layouts, especially length of line of sight, but also by using background knowledge to evaluate landmarks with respect to their probable spatial relation to a target. Questionnaire results revealed that participants have consistent background knowledge about the relative position of target locations. Landmarks were rated significantly differently with respect to their spatial relation to targets. In addition, results from a forced-choice task comparing snapshots of a virtual environment revealed that background knowledge influenced wayfinding decisions. We suggest that landmarks are interpreted semantically with respect to their function and spatial relation to the target location and thereby influence wayfinding decisions. This indicates that background knowledge plays a role in wayfinding. PMID:22806666

Frankenstein, Julia; Brüssow, Sven; Ruzzoli, Felix; Hölscher, Christoph

2012-08-01

369

Estimativas da composição anatômica da carcaça de frangos de corte com base no nível de proteína da ração e peso da carcaça / Estimation of the carcasses anatomical composition of broiler from diet quality and carcass weight  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Um experimento foi desenvolvido com o objetivo de estimar as proporções dos cortes nobres da carcaça de frangos de corte pelo modelo linear. Foram utilizados 842 frangos machos da linhagem Avian Farms, de 22 a 42 dias de idade, distribuídos num delineamento inteiramente ao acaso em esquema fatorial [...] 3x4. Foram fornecidas rações formuladas à base de milho e farelo de soja para conter 2.900 kcal de EM e 15,43; 17,26; 19,60; e 22,60% de PB; 3.100 kcal de EM e 16,49; 18,45; 20,95; e 24,22% de PB; e 3300 kcal de EM e 17,55; 19,64; 22,30; e 25,78% de PB, totalizando doze tratamentos. Cada tratamento foi constituído por quatro repetições de 18 aves. Fortes correlações foram observadas entre o peso vivo aos 42 dias e o peso da carcaça (r = 0,958), o peso da carcaça e o peso de pernas (r = 0,991), peso de peito+osso+pele (r = 0,965) e peso de peito desossado (r = 0,950). A porcentagem de lipídio foi negativamente correlacionada com a porcentagem de umidade da carcaça (r = -0,880). A equação linear é recomendada para a predição dos componentes anatômicos da carcaça de frangos de corte. Abstract in english An experiment was carried out to estimate the relations between broiler carcass weight and thighs+drumsticks, breast+bone+skin, and breast meat by the linear model. Eight hundred and sixty and four male poultry of Arbor Acres strain, from 22 to 42 days of age, were assigned to a completely randomize [...] d design in 3x4factorial scheme. Corn and soybean meal based diets were prepared to contain 2900 kcal ME and 15.43; 17.26; 19.60; and 22.60% CP; 3,100 kcal ME and 16.49; 18.45; 20.95; and 24.22%CP; and 3300 kcal ME and 17.55; 19.64; 22.30; and 25.78% CP, resulting in twelve treatments. Each treatment was constituted of four replicates of 18 birds. High correlations were observed between live weight at 42 days old and carcass weight (r = 0.958), carcass weight and thighs+drumsticks (r = 0.991), breast+bone+skin (r = 0.965) and deboned breast meat weight (r = 0.950). The lipid percentage was negatively correlated to the moisture percentage (r = -0.880). The linear equation is recommended to estimate carcass anatomical components in broiler chickens.

José Humberto Vilar da, Silva; Luís Fernando Teixeira, Albino; Adriana Helena do, Nascimento.

2003-04-01

370

Cardiac Anatomic Considerations in Pediatric Electrophysiology  

Directory of Open Access Journals (Sweden)

Full Text Available Although interventional electrophysiology and the use of radiofrequency energy to cure various arrhythmias primarily developed in the adult population, similar applications in children have grown dramatically over the last decade. The anatomic basis for various arrhythmias is critically important for the pediatric ablationists to appreciate. Such understanding allows the use of alternative technique to affect cure while avoiding complications. Further, because of the relatively small heart and less thick myocardium in children, without the appreciation of the underlying cardiac anatomic relationships, collateral injury, for example to the arterial system, may occur. In this review, the cardiac anatomic consideration important in approaching various supraventricular and ventricular arrhythmias in the normal heart is discussed.

Samuel J. Asirvatham

2008-05-01

371

Anatomical basis for Wilms tumor surgery  

Directory of Open Access Journals (Sweden)

Full Text Available Wilms tumor surgery requires meticulous planning and sophisticated surgical technique. Detailed anatomical knowledge can facilitate the uneventful performance of tumor nephrectomy and cannot be replaced by advanced and sophisticated imaging techniques. We can define two main goals for surgery: (1 exact staging as well as (2 safe and complete resection of tumor without spillage. This review aims to review the anatomical basis for Wilms tumor surgery. It focuses on the surgical anatomy of retroperitoneal space, aorta, vena cava and their large branches with lymphatics. Types and management of vascular injuries are discussed.

Trobs R

2009-01-01

372

Use of Landmark Features and Geometry by Children and Adults during a Two-Dimensional Search Task  

Science.gov (United States)

Three- to six-year-old children (n=28) and adults (n=46) participated in a two-dimensional search task that included geometry and feature conditions. During each of 24 trials, participants watched as a cartoon character hid behind one of three landmarks arranged in a triangle on a computer screen. The landmarks and character then disappeared and…

Gibson, Brett M.; Leichtman, Michelle D.; Kung, Deborah A.; Simpson, Michael J.

2007-01-01

373

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  

Energy Technology Data Exchange (ETDEWEB)

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.)

Abreu, Marcelo R. [University of California San Diego, VA Health Care System, San Diego, CA (United States); Chung, Christine B.; Trudell, Debra; Resnick, Donald [University of California San Diego, VA Health Care System, San Diego, CA (United States); Hospital Mae de Deus, Porto Alegre, RS (Brazil)

2008-04-15

374

Anatomical single bundle anterior cruciate ligament reconstruction  

OpenAIRE

We present a review of the literature looking at the anatomy of the Anterior Cruciate Ligament, the biomechanical aspects of ACL reconstruction, review the outcomes of single and double bundle ACL reconstruction and present the current techniques for anatomic single bundle reconstruction.

Carmont, Michael R.; Scheffler, Sven; Spalding, Tim; Brown, Jeremy; Sutton, Paul M.

2011-01-01

375