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1

Detecting corpus callosum abnormalities in autism based on anatomical landmarks  

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Autism is a severe developmental disorder whose neurological basis is largely unknown. Autism is a subtype of autism that displays more homogeneous features within group. The aim of this study was to identify the shape differences of the corpus callosum between patients with autism and the controls. Anatomical landmarks were collected from mid-sagittal MRI of 25 patients and 18 controls. Euclidean distance matrix analysis and thin-plate spline were used to analyze the landmark forms. Point-by...

Duan, Ye; Karsch, Kevin; Miles, Judith

2010-01-01

2

Anatomical landmarks for transnasal endoscopic skull base surgery.  

Science.gov (United States)

Resection of midline skull base lesions involve approaches needing extensive neurovascular manipulation. Transnasal endoscopic approach (TEA) is minimally invasive and ideal for certain selected lesions of the anterior skull base. A thorough knowledge of endonasal endoscopic anatomy is essential to be well versed with its surgical applications and this is possible only by dedicated cadaveric dissections. The goal in this study was to understand endoscopic anatomy of the orbital apex, petrous apex and the pterygopalatine fossa. Six cadaveric heads (3 injected and 3 non injected) and 12 sides, were dissected using a TEA outlining systematically, the steps of surgical dissection and the landmarks encountered. Dissection done by the "2 nostril, 4 hands" technique, allows better transnasal instrumentation with two surgeons working in unison with each other. The main surgical landmarks for the orbital apex are the carotid artery protuberance in the lateral sphenoid wall, optic nerve canal, lateral optico-carotid recess, optic strut and the V2 nerve. Orbital apex includes structures passing through the superior and inferior orbital fissure and the optic nerve canal. Vidian nerve canal and the V2 are important landmarks for the petrous apex. Identification of the sphenopalatine artery, V2 and foramen rotundum are important during dissection of the pterygopalatine fossa. In conclusion, the major potential advantage of TEA to the skull base is that it provides a direct anatomical route to the lesion without traversing any major neurovascular structures, as against the open transcranial approaches which involve more neurovascular manipulation and brain retraction. Obviously, these approaches require close cooperation and collaboration between otorhinolaryngologists and neurosurgeons. PMID:21744072

Sandu, Kishore; Monnier, Philippe; Pasche, Philippe

2012-01-01

3

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

International Nuclear Information System (INIS)

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

4

Robust Anatomical Landmark Detection for MR Brain Image Registration  

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Correspondence matching between MR brain images is often challenging due to large inter-subject structural variability. In this paper, we propose a novel landmark detection method for robust establishment of correspondences between subjects. Specifically, we first annotate distinctive landmarks in the training images. Then, we use regression forest to simultaneously learn (1) the optimal set of features to best characterize each landmark and (2) the non-linear mappings from local patch appearances of image points to their displacements towards each landmark. The learned regression forests are used as landmark detectors to predict the locations of these landmarks in new images. Since landmark detection is performed in the entire image domain, our method can cope with large anatomical variations among subjects. We evaluated our method by applying it to MR brain image registration. Experimental results indicate that by combining our method with existing registration method, obvious improvement in registration accuracy can be achieved. PMID:25333117

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

2014-01-01

5

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

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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

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Safe Treatment of Trigger Thumb With Longitudinal Anatomic Landmarks  

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

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

2010-01-01

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Characteristics of anatomical landmarks in the mandibular interforaminal region: A cone-beam computed tomography study  

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Objectives: This study was conducted to assess appearance, visibility, location and course of anatomical landmarks in mandibular interforaminal region using cone-beam computed tomography (CBCT). Study design: A total of 96 CBCT examinations was re-evaluated to exploit anatomical landmarks. The examinations used the Promax 3D CBCT unit. A sole examiner carried out all the measurements. Visibilities of the anatomical landmarks were scored using a four-point rating scale. Results: The mand...

Parnia, Fereidoun; Moslehifard, Elnaz; Hafezeqoran, Ali; Mahboub, Farhang; Mojaver-kahnamoui, Haniye

2012-01-01

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

International Nuclear Information System (INIS)

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

9

The use of anatomical landmarks for percutaneous nephrolithotomy  

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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

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[Anatomical key points and operative principle of "two planes and four landmarks" in extralevator abdominoperineal excision].  

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Abominoperineal resection (APR) is the main approach of lower rectal cancer treatment. Recently, it was found that conventional APR had higher incidence rate of positive circumferential resection margin(CRM) and intraoperative perforation (IOP), which was the crucial reason of local recurrence and worse prognosis. Extralevator abdominoperineal excision(ELAPE) procedure was proposed by European panels including surgeons, radiologist and pathologists, and considered to lower the positive rates of CRM and IOP. Definitive surgical planes and anatomic landmarks are the cores of this procedure, which are the prerequisite for the guarantee of safety and smoothness of surgery. To realize the anatomy of muscles, fascias, blood vessels and nervous of perineal region is the base of carrying out ELAPE procedure. In this paper, we introduce the key anatomy related to ELAPE procedure and summarize the principle of ELAPE procedure as "two planes and four landmarks", which will be beneficial to the popularization and application. PMID:25421764

Ye, Yingjiang; Shen, Zhanlong; Wang, Shan

2014-11-01

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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

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Detection and location of 127 anatomical landmarks in diverse CT datasets  

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The automatic detection and localization of anatomical landmarks has wide application, including intra and interpatient registration, study location and navigation, and the targeting of specialized algorithms. In this paper, we demonstrate the automatic detection and localization of 127 anatomically defined landmarks distributed throughout the body, excluding arms. Landmarks are defined on the skeleton, vasculature and major organs. Our approach builds on the classification forests method,1 using this classifier with simple image features which can be efficiently computed. For the training and validation of the method we have used 369 CT volumes on which radiographers and anatomists have marked ground truth (GT) - that is the locations of all defined landmarks occurring in that volume. A particular challenge is to deal with the wide diversity of datasets encountered in radiology practice. These include data from all major scanner manufacturers, different extents covering single and multiple body compartments, truncated cardiac acquisitions, with and without contrast. Cases with stents and catheters are also represented. Validation is by a leave-one-out method, which we show can be efficiently implemented in the context of decision forest methods. Mean location accuracy of detected landmarks is 13.45mm overall; execution time averages 7s per volume on a modern server machine. We also present localization ROC analysis to characterize detection accuracy - that is to decide if a landmark is or is not present in a given dataset.

Dabbah, Mohammad A.; Murphy, Sean; Pello, Hippolyte; Courbon, Romain; Beveridge, Erin; Wiseman, Stewart; Wyeth, Daniel; Poole, Ian

2014-03-01

13

Characteristics of anatomical landmarks in the mandibular interforaminal region: A cone-beam computed tomography study  

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Objectives: This study was conducted to assess appearance, visibility, location and course of anatomical landmarks in mandibular interforaminal region using cone-beam computed tomography (CBCT). Study design: A total of 96 CBCT examinations was re-evaluated to exploit anatomical landmarks. The examinations used the Promax 3D CBCT unit. A sole examiner carried out all the measurements. Visibilities of the anatomical landmarks were scored using a four-point rating scale. Results: The mandibular foramen, anterior loop, incisive canal and lingual foramen were observed in 100,84,83,49 % of the images, respectively. The mean size, diameter and width of anterior loop, incisive canal and lingual foramen were obtained 3.54± 1.41, 1.47±0.50 and 0.8 ± 0.09mm, respectively. Conclusion: It is not safe to recommend any definite distance mesially from the mental foramen. The diameter of the canals and foramens should be determined on a case-by-case basis to exploit the appropriate location for each individual. Key words:Anatomical landmarks, cone-beam computed tomography, implant surgery, radiographic evaluation, surgical complications. PMID:22143718

Parnia, Fereidoun; Hafezeqoran, Ali; Mahboub, Farhang; Mojaver-Kahnamoui, Haniye

2012-01-01

14

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

International Nuclear Information System (INIS)

rebrain 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.)

15

Are anatomical landmark measurements accurate for predicting endotracheal tube depth?  

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

Devanand Mangar

2013-03-01

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

Energy Technology Data Exchange (ETDEWEB)

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

Peters, Anton R.; Herk, Marcel van [Department of Radiotherapy, The Netherlands Cancer Institute/Antoni van Leeuwenhoek Huis (NKI/AVL), Plesmanlaan 121, 1066 CX Amsterdam (Netherlands); Muller, Sara H. [Department of Radiotherapy, The Netherlands Cancer Institute/Antoni van Leeuwenhoek Huis (NKI/AVL), Plesmanlaan 121, 1066 CX Amsterdam (Netherlands); Department of Radiology, NKI/AVL, Amsterdam (Netherlands); Munck, Jan C. de [MEG Centrum KNAW, Free University Hospital, De Boelelaan 1117, 1081 HV Amsterdam (Netherlands)

2000-08-01

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The resident's ridge as an arthroscopic landmark for anatomical femoral tunnel drilling in ACL reconstruction.  

Science.gov (United States)

The purposes of this study were to establish the technique to arthroscopically identify the resident's ridge without bony notchplasty even in patients with chronic ACL insufficiency and to elucidate if the ridge could be used as a landmark for anatomical femoral tunnel for ACL graft. There were 50 consecutive patients undergoing arthroscopic ACL reconstruction. With the thigh kept horizontal using a leg holder, a meticulous effort was made to find out a linear ridge running proximo-distal in a posterior one-third of the lateral notch wall, after removal of superficial soft tissue with radiofrequency energy. If the ridge was found, a socket with a rectangular aperture of 5 x 10 mm was created just behind the ridge. At 3-4-weeks post surgery, three-dimensional computed tomography (3-D CT) was performed to geographically identify the location of the ridge using the socket as a reference. Arthroscopically, a linear ridge running from superior-anterior to inferior-posterior on the lateral notch wall was consistently observed 7-10 mm anterior to the posterior articular cartilage margin of the lateral femoral condyle in all of the patients. The 3-D CT pictures proved the arthroscopically identified ridge to be the resident's ridge. The resident's ridge is arthroscopically identifiable after non-mechanical removal of the soft tissues without bony notchplasty. The ridge is a useful landmark for anatomical femoral tunnel drilling in arthroscopic ACL reconstruction. PMID:19915823

Shino, Konsei; Suzuki, Tomoyuki; Iwahashi, Takehiko; Mae, Tatsuo; Nakamura, Norimasa; Nakata, Ken; Nakagawa, Shigeto

2010-09-01

18

Verification of selected anatomic landmarks used as reference points for universal goniometer positioning during knee joint mobility range measurements.  

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The study was concerned with verification of the selection of reference points used for knee joint mobility range goniometry. The verification was based on photometric and electrogoniometric methods of femorotibial angle measurements. The material for measurements were three knee joint preparations. The obtained data were subjected to descriptive analysis; photographic documentation of geometric relations between the reference points was also prepared. Considerable divergence of measurement results was observed with respect to the actual knee joint flexion angle, amounting even to 16 degrees. The differences are due to the selection of anatomic landmarks, and depend in particular on the distance of the point to which the goniometer axis is applied from the approximate location of the mechanical joint axis. The corrections of knee joint flexion angle measurements were also estimated on the basis of data obtained from the photographs and the derived mathematical formula. PMID:11257742

Szulc, P; Lewandowski, J; Marecki, B

2001-01-01

19

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

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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

2015-05-01

20

Arterial tree tracking from anatomical landmarks in magnetic resonance angiography scans  

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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

 
 
 
 
21

Anatomic landmarks of fluoroscopy guided puncture of the pulseless femoral artery  

International Nuclear Information System (INIS)

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

22

Automatic Evaluation of Landmarks for Image-Based Navigation Update  

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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

23

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

24

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

International Nuclear Information System (INIS)

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

25

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

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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

26

Endoscopic orientation of the parasellar region in sphenoid sinus with ill-defined bony landmarks: an anatomic study.  

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The sphenoid bony landmarks are important for endoscopic orientation in skull base surgery but show a wide range of variations. We aimed to describe an instructional model for the endoscopic parasellar anatomy in sphenoid sinuses with ill-defined bony landmarks. Five preserved injected cadaveric heads and four sides of dry skulls were studied endoscopically via transethmoid, transsphenoidal approach. The parasellar region was exposed by drilling along the maxillary nerve (V2) canal [the length of the foramen rotundum (FR) between the middle cranial fossa and the pterygopalatine fossa]. This was achieved by drilling in the inferior part of the lateral wall of posterior ethmoids immediately above the sphenopalatine foramen. Cavernous V2 was traced to the paraclival internal carotid artery (ICA). Cavernous sinus (CS) apex was exposed by drilling a triangle bounded by V2 and its canal inferiorly, bone between FR and superior orbital fissure (SOF) anteriorly, and ophthalmic nerve (V1) superiorly. Drilling was continued toward the annulus of Zinn (AZ) and optic nerve superiorly and over the intracavernous ICA posteriorly. Endoscopic measurements between V2, SOF, AZ, and opticocarotid recess were obtained. Endoscopic systematic orientation of parasellar anatomy is presented that can be helpful for approaching sphenoid sinus with ill-defined bony landmarks. PMID:21772799

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

2010-11-01

27

Three-dimensional analysis of maxillary anatomic landmarks for greater palatine nerve block anesthesia.  

Science.gov (United States)

Greater palatine nerve block anesthesia (GPNBA) is a local anesthetic procedure used for maxillary and nasal treatment. Investigation of the three-dimensional anatomic location of the greater palatine foramen (GPF) is important for successful local anesthesia. The study aim was to provide standards for anatomic structures in the oral cavity that can be easily referred to in GPNBA. Maxillary computed tomography data were obtained from patients between 8 and 16 years of age whose maxillary incisors and first molars had already erupted (the growth group, n = 103); changes in the maxilla were observed over time in this group. Reference values for GPNBA in adults were measured in 107 patients older than 18 years. Maxillary computed tomography images were reconstructed three-dimensionally. Regression analysis demonstrates that all maxillary measurements in the growth group except for the distance from the posterior nasal spine to the GPF in the coronal plane correlated significantly with age. In adults, the mean perpendicular distance from the interdental alveolar bone between the left and right central incisors (1alvB) to the GPF in the coronal plane was 46.16 mm, and the mean distance from 1alvB to the GPF was 51.05 mm. The mean distance from the maxillary central incisor to the GPF was 57.58 mm. The mean angle between the line from the maxillary central incisor to each GPF and the sagittal plane was 16.49 degrees. The mean perpendicular distance from the anterior nasal spine to the GPF in the coronal plane was 43.49 mm, whereas the mean perpendicular distance from the GPF to the bone plane was 12.67 mm, and the mean perpendicular distance from the GPF to the occlusal plane was 22.13 mm. These measurements can be used to find the height of the GPF. In adults, the measured perpendicular distance from the incisive foramen to the GPF in the coronal plane was 32.04 mm, and the perpendicular distance from the median of the line that connects both of the contact points between the maxillary tuberosity and the pterygoid plate to the GPF in the coronal plane was 5.23 mm. Three-dimensional reference values relative to the anatomic structures in the oral cavity may increase the success rate of GPNBA and reduce complications. Although the maxillary growth pattern was analyzed, a limitation of this study is that maxillary anatomic measurements were not analyzed with regard to race or ethnicity. PMID:22627432

Kang, Sang-Hoon; Byun, In-Young; Kim, Jin-Hong; Park, Hee-Keun; Kim, Moon-Key

2012-05-01

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

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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

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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

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

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

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

2008-06-15

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

International Nuclear Information System (INIS)

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

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

CERN Document Server

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

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

1999-01-01

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

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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

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Active shape models incorporating isolated landmarks for medical image annotation  

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Apart from their robustness in anatomic surface segmentation, purely surface based 3D Active Shape Models lack the ability to automatically detect and annotate non-surface key points of interest. However, annotation of anatomic landmarks is desirable, as it yields additional anatomic and functional information. Moreover, landmark detection might help to further improve accuracy during ASM segmentation. We present an extension of surface-based 3D Active Shape Models incorporating isolated non-surface landmarks. Positions of isolated and surface landmarks are modeled conjoint within a point distribution model (PDM). Isolated landmark appearance is described by a set of haar-like features, supporting local landmark detection on the PDM estimates using a kNN-Classi er. Landmark detection was evaluated in a leave-one-out cross validation on a reference dataset comprising 45 CT volumes of the human liver after shape space projection. Depending on the anatomical landmark to be detected, our experiments have shown in about 1/4 up to more than 1/2 of all test cases a signi cant improvement in detection accuracy compared to the position estimates delivered by the PDM. Our results encourage further research with regard to the combination of shape priors and machine learning for landmark detection within the Active Shape Model Framework.

Norajitra, Tobias; Meinzer, Hans-Peter; Stieltjes, Bram; Maier-Hein, Klaus H.

2014-03-01

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Indoor Localization System based on Artificial Landmarks and Monocular Vision  

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Full Text Available This paper presents a visual localization approach well suited for the domestic and industrial environments due to its ability to provide an accurate, reliable and robust pose estimation.The mobile robot is equipped with a single camera to update their pose whenever a landmark is available on the field of view.The innovation presented by this research focus, especially, on the artificial landmark that has the ability to detect the presence of the robot, sinceboth entities communicates with each other using an infrared signal protocol modulated in frequency. Besides this communication ability, each landmark has several high intensity light-emitting diodes (leds that shine only for some instances according with the communication, which enables a synchronization between the camera shutter and the blinking of leds. This synchronization increases the system tolerance concerning to the changes in brightness of the ambient lights over time, independently of the landmarks location. The environment’s ceiling is populated with theselandmarks and an Extended Kalman Filter is usedto combine the dead-reckoning and landmark information. This increases the flexibility of the system by reducing the number of landmarks needed. The experimental evaluation of the proposed system was conducted in a real indoor environment with an autonomous wheelchair prototype.

Paulo G. Costa

2012-12-01

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

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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

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Clinical evaluation of semi-automatic landmark-based lesion tracking software for CT-scans  

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Background To evaluate a semi-automatic landmark-based lesion tracking software enabling navigation between RECIST lesions in baseline and follow-up CT-scans. Methods The software automatically detects 44 stable anatomical landmarks in each thoraco/abdominal/pelvic CT-scan, sets up a patient specific coordinate-system and cross-links the coordinate-systems of consecutive CT-scans. Accuracy of the software was evaluated on 96 RECIST lesions (target- and non-target lesions) in baseline and follow-up CT-scans of 32 oncologic patients (64 CT-scans). Patients had to present at least one thoracic, one abdominal and one pelvic RECIST lesion. Three radiologists determined the deviation between lesions’ centre and the software’s navigation result in consensus. Results The initial mean runtime of the system to synchronize baseline and follow-up examinations was 19.4?±?1.2 seconds, with subsequent navigation to corresponding RECIST lesions facilitating in real-time. Mean vector length of the deviations between lesions’ centre and the semi-automatic navigation result was 10.2?±?5.1 mm without a substantial systematic error in any direction. Mean deviation in the cranio-caudal dimension was 5.4?±?4.0 mm, in the lateral dimension 5.2?±?3.9 mm and in the ventro-dorsal dimension 5.3?±?4.0 mm. Conclusion The investigated software accurately and reliably navigates between lesions in consecutive CT-scans in real-time, potentially accelerating and facilitating cancer staging.

2014-01-01

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

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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

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Spatial cognition based on geometry and landmarks in the domestic chick (Gallus gallus).  

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Recent evidence suggest that encoding of spatial information based on extended surfaces may differ from encoding based on discrete arrays of local elements. Here we investigated the use of these different frames of reference in domestic chicks. Chicks were trained to search for food hidden under sawdust in the center of the floor of a square-shaped landmark array, with its center in coincidence with the center of a square-shaped enclosure. Displacement of the array to a corner caused a shift of searching behavior toward the array, the search activity spanning between the center of the arena and the center of the array. After changing distances between landmarks, chicks still searched in the central area. Asymmetries were apparent in chicks tested in monocular conditions, with left-eyed chicks being more affected by the overall enclosure and right-eyed chicks by local landmarks. These results suggest that chicks can use both distances from extended surfaces and local information provided by the landmarks of the array to orient in space. However, chicks do not seem to perceive the array as a whole configuration, rather they tend to rely only on single landmarks to locate the goal. PMID:16979247

Chiesa, A Della; Speranza, M; Tommasi, L; Vallortigara, G

2006-11-25

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Landmark matching based retinal image alignment by enforcing sparsity in correspondence matrix.  

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Retinal image alignment is fundamental to many applications in diagnosis of eye diseases. In this paper, we address the problem of landmark matching based retinal image alignment. We propose a novel landmark matching formulation by enforcing sparsity in the correspondence matrix and offer its solutions based on linear programming. The proposed formulation not only enables a joint estimation of the landmark correspondences and a predefined transformation model but also combines the benefits of the softassign strategy (Chui and Rangarajan, 2003) and the combinatorial optimization of linear programming. We also introduced a set of reinforced self-similarities descriptors which can better characterize local photometric and geometric properties of the retinal image. Theoretical analysis and experimental results with both fundus color images and angiogram images show the superior performances of our algorithms to several state-of-the-art techniques. PMID:24238743

Zheng, Yuanjie; Daniel, Ebenezer; Hunter, Allan A; Xiao, Rui; Gao, Jianbin; Li, Hongsheng; Maguire, Maureen G; Brainard, David H; Gee, James C

2014-08-01

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

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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

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Simulation of local anaesthetic nerve block of the infraorbital nerve within the pterygopalatine fossa: anatomical landmarks defined by computed tomography.  

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To provide anaesthesia of the maxillary cheek teeth, a local block of the infraorbital nerve in the pterygopalatine fossa has been suggested. The aim of this study was to re-examine the anatomy of the pterygopalatine fossa, giving special attention to relevant arteries, veins and nerves; simulate the infiltration of an anaesthetic by injecting a contrast medium; improve the injection technique to avoid puncturing of relevant anatomical structures. Five heads and two living horses were investigated using contrast medium injections and computed tomography (CT). Needles were inserted using two insertion techniques: "Palatine Bone Insertion" (PBI) and "Extraperiorbital Fat Body Insertion" (EFBI). Both techniques are suitable for achieving a consistent distribution of contrast medium around the infraorbital nerve. The periorbita prevents the contrast medium from penetrating into the intraperiorbital compartment. The EFBI-technique is most appropriate for providing a sufficient infraorbital nerve block with a minimised risk of complications. PMID:18371997

Staszyk, Carsten; Bienert, Astrid; Bäumer, Wolfgang; Feige, Karsten; Gasse, Hagen

2008-12-01

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Robust 3D Face Landmark Localization Based on Local Coordinate Coding.  

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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

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A Descriptive Comparison of Ultrasound Guided Central Venous Cannulation of the Internal Jugular to Landmark Based Subclavian Vein Cannulation  

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The safest site for central venous cannulation (CVC) remains debated. Many emergency medicine physicians advocate the ultrasound guided internal jugular approach (USIJ) because of data supporting its efficiency. However, a number of physicians prefer, and are most comfortable with, the subclavian vein approach. The purpose of this study was to describe adverse event rates among operators using the USIJ approach and the landmark subclavian vein approach without ultrasound (SC). Methods This was a prospective observational trial of patients undergoing CVC of the subclavian or internal jugular veins in the Emergency Department (ED). Physicians performing the procedures did not undergo standardized training in either technique. The primary outcome was a composite of adverse events defined as hematoma, arterial cannulation, pneumothorax, and failure to cannulate. Physicians recorded the anatomical site of cannulation, ultrasound assistance, indications and acute complications. Variables of interest were collected from the pharmacy and ED record. Physician experience was based on a self-reported survey. We followed outcomes of central line insertion until device removal or patient discharge. Results Physicians attempted 236 USIJ and 132 SC cannulations on 333 patients. The overall adverse event rate was 22% with failure to cannulate being the most common. Adverse events occurred in 19% of USIJ attempts compared to 29% of non-ultrasound guided subclavian attempts. Among highly experienced operators CVCs placed at the subclavian site resulted in more adverse events than those performed using USIJ (RR=1.89, 95%CI 1.05 to 3.39). Conclusions While limited by observational design, our results suggest that the USIJ technique may result in fewer adverse events compared to the landmark SC approach. PMID:20370781

Theodoro, Daniel; Bausano, Brian; Lewis, Lawrence; Evanoff, Bradley; Kollef, Marin

2013-01-01

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

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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

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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  

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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

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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  

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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

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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  

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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

49

Physics-based elastic image registration using splines and including landmark localization uncertainties.  

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We introduce an elastic registration approach which is based on a physical deformation model and uses Gaussian elastic body splines (GEBS). We formulate an extended energy functional related to the Navier equation under Gaussian forces which also includes landmark localization uncertainties. These uncertainties are characterized by weight matrices representing anisotropic errors. Since the approach is based on a physical deformation model, cross-effects in elastic deformations can be taken into account. Moreover, we have a free parameter to control the locality of the transformation for improved registration of local geometric image differences. We demonstrate the applicability of our scheme based on 3D CT images from the Truth Cube experiment, 2D MR images of the brain, as well as 2D gel electrophoresis images. It turns out that the new scheme achieves more accurate results compared to previous approaches. PMID:17354831

Wörz, Stefan; Rohr, Karl

2006-01-01

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

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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

51

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

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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

52

Bilateral Breast Asymmetry Detection using Intensity Histogram and Landmark based Registration Technique  

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Full Text Available Breast cancer is a serious health challenge faced all over the world. The cause of which is unclear so prevention is not possible. Effective monitoring by screening programs is the only solution for early detection and cure for this disease. Increasing awareness has led to mass screening programs that are generating huge number of mammograms that are required to be examined by radiologists. Determination of asymmetry between mammogram pairs may be indicative to the presence of possible abnormalities. Any change within the tissues results in variations in the anatomy of the organs. Such changes are also reflected, more often, morphologically in the shape and structure of the breasts. It is possible to detect the difference of structures and anatomy between the breast pair. In this paper we have developed algorithms and methodologies for CAD based determination of both morphological and anatomical asymmetry. The results obtained effectively identified both anatomical and morphological asymmetry in comparison to normal pairs.

Samir Kumar Bandyopadhyay

2012-09-01

53

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

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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

54

Toward a model for lexical access based on acoustic landmarks and distinctive features  

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This article describes a model in which the acoustic speech signal is processed to yield a discrete representation of the speech stream in terms of a sequence of segments, each of which is described by a set (or bundle) of binary distinctive features. These distinctive features specify the phonemic contrasts that are used in the language, such that a change in the value of a feature can potentially generate a new word. This model is a part of a more general model that derives a word sequence from this feature representation, the words being represented in a lexicon by sequences of feature bundles. The processing of the signal proceeds in three steps: (1) Detection of peaks, valleys, and discontinuities in particular frequency ranges of the signal leads to identification of acoustic landmarks. The type of landmark provides evidence for a subset of distinctive features called articulator-free features (e.g., [vowel], [consonant], [continuant]). (2) Acoustic parameters are derived from the signal near the landmarks to provide evidence for the actions of particular articulators, and acoustic cues are extracted by sampling selected attributes of these parameters in these regions. The selection of cues that are extracted depends on the type of landmark and on the environment in which it occurs. (3) The cues obtained in step (2) are combined, taking context into account, to provide estimates of ``articulator-bound'' features associated with each landmark (e.g., [lips], [high], [nasal]). These articulator-bound features, combined with the articulator-free features in (1), constitute the sequence of feature bundles that forms the output of the model. Examples of cues that are used, and justification for this selection, are given, as well as examples of the process of inferring the underlying features for a segment when there is variability in the signal due to enhancement gestures (recruited by a speaker to make a contrast more salient) or due to overlap of gestures from neighboring segments.

Stevens, Kenneth N.

2002-04-01

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Dissimilarity-Based Classification of Anatomical Tree Structures  

DEFF Research Database (Denmark)

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

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

2011-01-01

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The Jugular Dural Fold—A Helpful Skull Base Landmark to the Cranial Nerves  

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During a retrosigmoid (or combined retrolabyrinthine-retrosigmoid) approach to the posterior fossa for vestibular neurectomy or removal of small acoustic neuromas, a white dural fold is a consistent landmark to cranial nerves VII through XII. This fold of dura appears as a white linear structure extending from the foramen magnum across the sigmoid sinus, attaching to the posterior aspect of the temporal bone, anterior to the vestibular aqueduct. The name “jugular dural fold” is suggested ...

Silverstein, Herbert; Willcox, Thomas O.; Rosenberg, Seth I.; Seidman, Michael D.

1995-01-01

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Towards a new speech event detection approach for landmark-based speech recognition  

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In this work, we present a new approach for the classification and detection of speech units for the use in landmark or eventbased speech recognition systems. We use segmentation to model any time-variable speech unit by a fixed-dimensional observation vector, in order to train a committee of boosted decision stumps on labeled training data. Given an unknown speech signal, the presence of a desired speech unit is estimated by searching for each time frame the corresponding segment, that provi...

Ziegler, Stefan; Ludusan, Bogdan; Gravier, Guillaume

2012-01-01

58

High-precision Detection of Facial Landmarks to Estimate Head Motions Based on Vision Models  

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Full Text Available A new approach of determination of head movement is presented from the pictures recorded via digital cameras monitoring the scanning processing of PET. Two human vision models of CIECAMs and BMV are applied to segment the face region via skin colour and to detect local facial landmarks respectively. The developed algorithms are evaluated on the pictures (n=12 monitoring a subject?s head while simulating PET scanning captured by two calibrated cameras (located in the front and left side from a subject. It is shown that centers of chosen facial landmarks of eye corners and middle point of nose basement have been detected with very high precision (1 0.64 pixels. Three landmarks on pictures received by the front camera and two by the side camera have been identified. Preliminary results on 2D images with known moving parameters show that movement parameters of rotations and translations along X, Y, and Z directions can be obtained very accurately via the described methods.

Xiaohong W. Gao

2007-01-01

59

Anatomically based lower limb nerve model for electrical stimulation  

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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 ...

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

2007-01-01

60

A Simple and Fast Method of 3D Registration and Statistical Landmark Localization for Sparse Multi-Modal/Time-Series Neuroimages Based on Cortex Ellipse Fitting.  

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Existing methods of neuroimage registration typically require high quality scans and are time-consuming. We propose a simple and fast method which allows intra-patient multi-modal and time-series neuroimage registration as well as landmark identification (including commissures and superior/inferior brain landmarks) for sparse data. The method is based on elliptical approximation of the brain cortical surface in the vicinity of the midsagittal plane (MSP). Scan registration is performed by a 3D affine transformation based on parameters of the cortex elliptical fit and by aligning the MSPs. The landmarks are computed using a statistical localization method based on analysis of 53 structural scans without detectable pathology. The method is illustrated for multi-modal registration, analysis of hemorrhagic stroke time series, and ischemic stroke follow ups, as well as for localization of hardly visible or not discernible landmarks in sparse neuroimages. The method also enables a statistical localization of landmarks in sparse morphological/non-morphological images, where landmark points may be invisible. PMID:24028883

Volkau, I; Puspitasari, F; Ng, T T; Bhanu Prakash, K N; Gupta, V; Nowinski, W L

2012-03-01

 
 
 
 
61

Automatic anatomical segmentation of the liver by separation planes  

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Surgical planning in oncological liver surgery is based on the location of the 8 anatomical segments according to Couinaud's definition and tumors inside these structures. The detection of the boundaries between the segments is then the first step of the preoperative planning. The proposed method, devoted to binary images of livers segmented from CT-scans, has been designed to delineate these segments. It automatically detects a set of landmarks using a priori anatomical knowledge and differential geometry criteria. These landmarks are then used to position the Couinaud's segments. Validations performed on 7 clinical cases tend to prove that the method is reliable for most of these separation planes.

Boltcheva, Dobrina; Passat, Nicolas; Agnus, Vincent; Jacob-Da, Marie-Andrée, , Col; Ronse, Christian; Soler, Luc

2006-03-01

62

Group-wise FMRI activation detection on corresponding cortical landmarks.  

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Group-wise activation detection in task-based fMRI has been widely used because of its robustness to noises and statistical power to deal with variability of individual brains. However, current group-wise fMRI activation detection methods typically rely on the spatial alignment established by coregistration of individual brains' fMRI images into the same template space, which has difficulty in dealing with the remarkable anatomic variation of different brains. As a consequence, the resulted misalignment among multiple brains could substantially degrade the accuracy and specificity of group-wise fMRI activation detection. To address these challenges, this paper presents a novel methodology to detect group-wise fMRI activation based on a publicly released dense map of DTI-derived structural cortical landmarks, which possess intrinsic correspondences across individuals and populations. The basic idea here is that a first-level general linear model (GLM) analysis is performed on fMRI signals of each corresponding cortical landmark in each individual brain's own space, and then the single-subject effect size of the same landmark from a group of subjects are statistically integrated and assessed at the group level using the mixed-effects model. As a result, the consistently activated cortical landmarks are determined and declared group-wisely in response to external block-based stimuli. Our experimental results demonstrated that the proposed approach can map meaningful group-wise activation patterns on the atlas of cortical landmarks without image registration between subjects and spatial smoothing. PMID:24579198

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

2013-01-01

63

Anatomically based lower limb nerve model for electrical stimulation  

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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

64

Feature-based groupwise registration by hierarchical anatomical correspondence detection.  

Science.gov (United States)

Groupwise registration has been widely investigated in recent years due to its importance in analyzing population data in many clinical applications. To our best knowledge, most of the groupwise registration algorithms only utilize the intensity information. However, it is well known that using intensity only is not sufficient to achieve the anatomically sound correspondences in medical image registration. In this article, we propose a novel feature-based groupwise registration algorithm to establish the anatomical correspondence across subjects by using the attribute vector that is defined as the morphological signature for each voxel. Similar to most of the state-of-the-art groupwise registration algorithms, which simultaneously estimate the transformation fields for all subjects, we develop an energy function to minimize the intersubject discrepancies on anatomical structures and drive all subjects toward the hidden common space. To make the algorithm efficient and robust, we decouple the complex groupwise registration problem into two easy-to-solve subproblems, namely (1) robust correspondence detection and (2) dense transformation field estimation, which are systematically integrated into a unified framework. To achieve the robust correspondences in the step (1), several strategies are adopted. First, the procedure of feature matching is evaluated within a neighborhood, rather than only on a single voxel. Second, the driving voxels with distinctive image features are designed to drive the transformations of other nondriving voxels. Third, we take advantage of soft correspondence assignment not only in the spatial domain but also across the population of subjects. Specifically, multiple correspondences are allowed to alleviate the ambiguity in establishing correspondences w.r.t. a particular subject and also the contributions from different subjects are dynamically controlled throughout the registration. Eventually in the step (2), based on the correspondences established for the driving voxels, thin-plate spline is used to propagate correspondences on the driving voxels to other locations in the image. By iteratively repeating correspondence detection and dense deformation estimation, all the subjects will be aligned onto the common space. Our feature-based groupwise registration algorithm has been extensively evaluated over 18 elderly brains, 16 brains from NIREP (with 32 manually delineated labels), 40 brains from LONI LPBA40 (with 54 manually delineated labels), and 12 pairs of normal controls and simulated atrophic brain images. In all experiments, our algorithm achieves more robust and accurate registration results, compared with another groupwise algorithm and a pairwise registration method. PMID:21391266

Wu, Guorong; Wang, Qian; Jia, Hongjun; Shen, Dinggang

2012-02-01

65

Establishing Cephalometric Landmarks for the Translational Study of Le Fort-based Facial Transplantation in Swine: Enhanced applications using computer-assisted surgery and custom cutting guides  

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Background Le Fort-based, maxillofacial allotransplantation is a reconstructive alternative gaining clinical acceptance. However, the vast majority of single-jaw transplant recipients demonstrate less-than-ideal skeletal and dental relationships with suboptimal aesthetic harmony. The purpose of this study was to investigate reproducible cephalometric landmarks in a large animal model, where refinement of computer-assisted planning, intra-operative navigational guidance, translational bone osteotomies, and comparative surgical techniques could be performed. Methods Cephalometric landmarks that could be translated into the human craniomaxillofacial skeleton, and would remain reliable following maxillofacial osteotomies with mid-facial alloflap inset, were sought on six miniature swine. Le Fort I-and Le Fort III-based alloflaps were harvested in swine with osteotomies, and all alloflaps were either auto-replanted or transplanted. Cephalometric analyses were performed on lateral cephalograms pre- and post-operatively. Critical cephalometric data sets were identified with the assistance of surgical planning and virtual prediction software, and evaluated for reliability and translational predictability. Results Several pertinent landmarks and human analogues were identified including pronasale (PRN), zygion (Zy), parietale (PA), gonion (GO), gnathion (GN), lower incisior base (LIB), and alveolare (ALV). PA-PRN-ALV and PA-PRN-LIB were found to be reliable correlates of SNA and SNB measurements in humans, respectively. Conclusions There is a set of reliable cephalometric landmarks and measurement angles pertinent for utilization within a translational large animal model. These craniomaxillofacial landmarks will allow us to develop novel navigational software technology, improve our cutting guide designs, and explore new avenues for investigation and collaboration. Level of Evidence N/A (Large Animal Study) PMID:24445879

Santiago, Gabriel F.; Susarla, Srinivas M.; Al Rakan, Mohammed; Coon, Devin; Rada, Erin M.; Sarhane, Karim; Shores, Jamie T.; Bonawitz, Steven C.; Cooney, Damon; Sacks, Justin; Murphy, Ryan J.; Fishman, Elliot K.; Brandacher, Gerald; Lee, WP Andrew; Liacouras, Peter; Grant, Gerald; Armand, Mehran; Gordon, Chad R.

2014-01-01

66

A Practical Subspace Approach To Landmarking  

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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

67

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

68

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.

69

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-02-15

70

A new automatic landmark extraction framework on ultrasound images of femoral condyles  

Science.gov (United States)

In Computer Assisted Orthopaedic Surgery (CAOS), surgeons have to acquire some anatomical landmarks as inputs to the system. To do so, they use manual pointers that are localized in the Operating Room (OR) space using an infrared camera. When the needed landmark is not reachable through an opening, it is palpated directly on skin and there is a loss of precision that can vary from several millimeters to centimeters depending on the thickness of soft tissues. In this paper, we propose a new framework based on three main steps to register the bone surface and extract automatically anatomical landmarks with an ultrasound probe. This framework is based on an oriented gradient calculation, a simulated-compound and a contour closure using a graph representation. The oriented gradient allows extracting a set of pixels that probably belong to the bone surface. The simulatedcompound step allows using ultrasound images properties to define a set of small segments which may belong to the bone surface, and the graph representation allows eliminating false positive detection among remaining segments. The proposed method has been validated on a database of 230 ultrasound images of anterior femoral condyles (on the knee). The average computation time is 0.11 sec per image, and average errors are: 0.54 mm for the bone surface extraction, 0.31 mm for the condylar line, and 1.4 mm for the trochlea middle.

Masson-Sibut, Agnès; Nakib, Amir; Petit, Eric; Leitner, François

2012-03-01

71

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

International Nuclear Information System (INIS)

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

72

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

Directory of Open Access Journals (Sweden)

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

Hampe O Baszio S

2010-06-01

73

Exploring the Anatomical Basis of Effective Connectivity Models with DTI-Based Fiber Tractography  

Directory of Open Access Journals (Sweden)

Full Text Available Diffusion tensor imaging (DTI is considered to be a promising tool for revealing the anatomical basis of functional networks. In this study, we investigate the potential of DTI to provide the anatomical basis of paths that are used in studies of effective connectivity, using structural equation modeling. We have taken regions of interest from eight previously published studies, and examined the connectivity as defined by DTI-based fiber tractography between these regions. The resulting fiber tracts were then compared with the paths proposed in the original studies. For a substantial number of connections, we found fiber tracts that corresponded to the proposed paths. More importantly, we have also identified a number of cases in which tractography suggested direct connections which were not included in the original analyses. We therefore conclude that DTI-based fiber tractography can be a valuable tool to study the anatomical basis of functional networks.

Frans A. J. Verstraten

2008-05-01

74

Hierarchical scale-based multiobject recognition of 3-D anatomical structures.  

Science.gov (United States)

Segmentation of anatomical structures from medical images is a challenging problem, which depends on the accurate recognition (localization) of anatomical structures prior to delineation. This study generalizes anatomy segmentation problem via attacking two major challenges: 1) automatically locating anatomical structures without doing search or optimization, and 2) automatically delineating the anatomical structures based on the located model assembly. For 1), we propose intensity weighted ball-scale object extraction concept to build a hierarchical transfer function from image space to object (shape) space such that anatomical structures in 3-D medical images can be recognized without the need to perform search or optimization. For 2), we integrate the graph-cut (GC) segmentation algorithm with prior shape model. This integrated segmentation framework is evaluated on clinical 3-D images consisting of a set of 20 abdominal CT scans. In addition, we use a set of 11 foot MR images to test the generalizability of our method to the different imaging modalities as well as robustness and accuracy of the proposed methodology. Since MR image intensities do not possess a tissue specific numeric meaning, we also explore the effects of intensity nonstandardness on anatomical object recognition. Experimental results indicate that: 1) effective recognition can make the delineation more accurate; 2) incorporating a large number of anatomical structures via a model assembly in the shape model improves the recognition and delineation accuracy dramatically; 3) ball-scale yields useful information about the relationship between the objects and the image; 4) intensity variation among scenes in an ensemble degrades object recognition performance. PMID:22203704

Bagci, Ulas; Chen, Xinjian; Udupa, Jayaram K

2012-03-01

75

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

76

Anatomical-based segmentation with stenosis bridging and gap closing in atherosclerotic cardiac MSCT  

Science.gov (United States)

In the diagnosis of coronary artery disease, 3D-multi-slice computed tomography (MSCT) has recently become more and more important. In this work, an anatomical-based method for the segmentation of atherosclerotic coronary arteries in MSCT is presented. This technique is able to bridge severe stenosis, image artifacts or even full vessel occlusions. Different anatomical structures (aorta, blood-pool of the heart chambers, coronary arteries and their orifices) are detected successively to incorporate anatomical knowledge into the algorithm. The coronary arteries are segmented by a simulated wave propagation method to be able to extract anatomically spatial relations from the result. In order to bridge segmentation breaks caused by stenosis or image artifacts, the spatial location, its anatomical relation and vessel curvature-propagation are taken into account to span a dynamic search space for vessel bridging and gap closing. This allows the prevention of vessel misidentifications and improves segmentation results significantly. The robustness of this method is proven on representative medical data sets.

Merges, Reto D.; Rinck, Daniel; Sühling, Michael; Dössel, Olaf; Scheuering, Michael

2006-03-01

77

Anatomical basis of lumboscopy.  

Science.gov (United States)

Lumboscopy provides an approach to the retroperitoneum for the majority of upper urinary tract operations. The technique involves a knowledge of specific anatomical landmarks that differ from those in classical open surgery, because of the inferior approach to the renal pedicle with the kidney initially mobilized in a ventral and cranial position. An anatomical study was conducted on five cadavers, using images from surgical operations, in order to describe the vascular elements of the retroperitoneal spaces as they are approached during lumboscopy, as well as to define specific anatomical landmarks. Identification of psoas major is crucial as it is then possible to locate the renal pedicle opposite and the area of the great vessels medially. During dissection of the renal pedicle the renal vein and its branches are the first elements to be approached. On the left side the distal portion of the renal vein can be confused with a reno-hemi-azygo-lumbar trunk, due to the initial ventral mobilization of the kidney stretching it. Because of the inferior view of the renal pedicle the reno-hemi-azygo-lumbar trunk can obscure part of the renal artery and may be confused with the renal vein. On the right side initial identification of the inferior vena cava on the medial aspect of psoas major facilitates identification of the gonadal, renal and suprarenal veins all located in the same plane. PMID:11490929

Yiou, R; Delmas, V; Chopin, D; Abbou, C C

2001-06-01

78

Enhancing Planning Heuristic with Landmarks  

Directory of Open Access Journals (Sweden)

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

Jingjing Zhao

2011-12-01

79

Two anatomic resources of canine pelvic limb muscles based on CT and MRI.  

Science.gov (United States)

Advances in magnetic resonance (MR) imaging and three-dimensional (3D) modeling software provide the tools necessary to create sophisticated, interactive anatomic resources that can assist in the interpretation of MR images of extremities, and learning the structure and function of limb musculature. Modeling provides advantages over dissection or consultation of print atlases because of the associated speed, flexibility, 3D nature, and elimination of superimposed arrows and labels. Our goals were to create a diagnostic atlas of pelvic limb muscles that will facilitate interpretation of MR images of patients with muscle injury and to create a 3D model of the canine pelvic limb musculature to facilitate anatomic learning. To create these resources, we used structural segmentation of MR images, a process that groups image pixels into anatomically meaningful regions. The Diagnostic Atlas is an interactive, multiplanar, web-based MR atlas of the canine pelvic limb musculature that was created by manually segmenting clinically analogous MR sequences. Higher resolution volumetric MR and computed tomography (CT) data were segmented into separately labeled volumes of data and then transformed into a multilayered 3D computer model. The 3D Model serves as a resource for students of gross anatomy, encouraging integrative learning with its highly interactive and selective display capabilities. For clinicians, the 3D Model also serves to bridge the gap between topographic and tomographic anatomy, displaying both formats alongside, or even superimposed over each other. Both projects are hosted on an open-access website, http://3dvetanatomy.ncsu.edu/ PMID:22360713

Sunico, Sarena K; Hamel, Corentin; Styner, Martin; Robertson, Ian D; Kornegay, Joe N; Bettini, Chris; Parks, Jerry; Wilber, Kathy; Smallwood, J Edgar; Thrall, Donald E

2012-01-01

80

Automated landmarking and labeling of fully and partially scanned spinal columns in CT images.  

Science.gov (United States)

The spinal column is one of the most distinguishable structures in CT scans of the superior part of the human body. It is not necessary to segment the spinal column in order to use it as a frame of reference. It is sufficient to place landmarks and the appropriate anatomical labels at intervertebral disks and vertebrae. In this paper, we present an automated system for landmarking and labeling spinal columns in 3D CT datasets. We designed this framework with two goals in mind. First, we relaxed input data requirements found in the literature, and we label both full and partial spine scans. Secondly, we intended to fulfill the performance requirement for daily clinical use and developed a high throughput system capable of processing thousands of slices in just a few minutes. To accomplish the aforementioned goals, we encoded structural knowledge from training data in probabilistic boosting trees and used it to detect efficiently the spinal canal, intervertebral disks, and three reference regions responsible for initializing the landmarking and labeling. Final landmarks and labels are selected by Markov Random Field-based matches of newly introduced 3-disk models. The framework has been tested on 36 CT images having at least one of the regions around the thoracic first ribs, the thoracic twelfth ribs, or the sacrum. In an average time of 2 min, we achieved a correct labeling in 35 cases with precision of 99.0% and recall of 97.2%. Additionally, we present results assuming none of the three reference regions could be detected. PMID:23978670

Major, David; Hlad?vka, Ji?í; Schulze, Florian; Bühler, Katja

2013-12-01

 
 
 
 
81

DETEKSI LANDMARK CITRA WAJAH DENGAN EXTRAKSI FITUR GABOR ANALISA FUZZY  

Directory of Open Access Journals (Sweden)

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

Resmana Lim

2003-01-01

82

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

83

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

84

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

85

36 CFR 65.5 - Designation of National Historic Landmarks.  

Science.gov (United States)

...property with multiple ownership it...appropriate. In making its recommendation...finds that the criteria of the landmarks...based on the criteria set forth herein, makes a decision on National Historic...properties with multiple...

2010-07-01

86

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

Science.gov (United States)

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. PMID:25306436

2014-01-01

87

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

88

Development of an anatomically based whole-body musculoskeletal model of the Japanese macaque (Macaca fuscata).  

Science.gov (United States)

We constructed a three-dimensional whole-body musculoskeletal model of the Japanese macaque (Macaca fuscata) based on computed tomography and dissection of a cadaver. The skeleton was modeled as a chain of 20 bone segments connected by joints. Joint centers and rotational axes were estimated by joint morphology based on joint surface approximation using a quadric function. The path of each muscle was defined by a line segment connecting origin to insertion through an intermediary point if necessary. Mass and fascicle length of each were systematically recorded to calculate physiological cross-sectional area to estimate the capacity of each muscle to generate force. Using this anatomically accurate model, muscle moment arms and force vectors generated by individual limb muscles at the foot and hand were calculated to computationally predict muscle functions. Furthermore, three-dimensional whole-body musculoskeletal kinematics of the Japanese macaque was reconstructed from ordinary video sequences based on this model and a model-based matching technique. The results showed that the proposed model can successfully reconstruct and visualize anatomically reasonable, natural musculoskeletal motion of the Japanese macaque during quadrupedal/bipedal locomotion, demonstrating the validity and efficacy of the constructed musculoskeletal model. The present biologically relevant model may serve as a useful tool for comprehensive understanding of the design principles of the musculoskeletal system and the control mechanisms for locomotion in the Japanese macaque and other primates. PMID:19115360

Ogihara, Naomichi; Makishima, Haruyuki; Aoi, Shinya; Sugimoto, Yasuhiro; Tsuchiya, Kazuo; Nakatsukasa, Masato

2009-07-01

89

Optimal Weighting of Landmarks for Face Recognition  

Directory of Open Access Journals (Sweden)

Full Text Available A new method named Landmark Model Matching was recently proposed for fully automatic face recognition. It was inspired by Elastic Bunch Graph Matching and Active Shape Model. Landmark Model Matching consists of four phases: creation of the landmark distribution model, face finding, landmark finding, and recognition. A drawback in Landmark Model Matching is that, in the recognition phase, the weights given to different landmarks or facial feature points were determined experimentally. In this work, we optimized the weights given to landmarks, and thereby improved the recognition rates for the two benchmarks used.

Rajinda S. Senaratne

2006-06-01

90

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

Science.gov (United States)

In order to provide scientific and empirical evidence for the clinical application of the polyaxial self-locking anatomical plate, 80 human tibias from healthy adults were scanned by spiral CT and their three-dimensional images were reconstructed using the surface shaded display (SSD) method. Firstly, based on the geometric data of distal tibia, a polyaxial self-locking anatomical plate for distal tibia was designed and constructed. Biomechanical tests were then performed by applying axial loading, 4-point bending, and axial torsion loading on the fracture fixation models of fresh cadaver tibias. Our results showed that variation in twisting angles of lateral tibia surface was found in various segments of the distal tibia. The polyaxial self-locking anatomical plate was constructed based on the geometry of the distal tibia. Compared to the conventional anatomical locking plate, the polyaxial self-locking anatomical plate of the distal tibia provides a better fit to the geometry of the distal tibia of the domestic population, and the insertion angle of locking screws can be regulated up to 30°. Collectively, this study assesses the geometry of the distal tibia and provides variable locking screw trajectory to improve screw-plate stability through the design of a polyaxial self-locking anatomical plate. PMID:25025051

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

2014-01-01

91

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

International Nuclear Information System (INIS)

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

92

Mapping melanoma lymphoscintigraphy data onto a 3D anatomically based model.  

Science.gov (United States)

This study describes three-dimensional (3D) visualization of two-dimensional (2D) melanoma lymphatic mapping data, to provide a framework for analysis of melanoma spread patterns and a platform for recording new lymphoscintigraphy (LS) data more accurately in 3D. Specifically, the Sydney Melanoma Unit's LS database of over 5000 patients' primary cutaneous melanoma sites and sentinel lymph nodes have been mapped from 2D images onto a 3D anatomically based model. Anatomically accurate model geometries were created using the Visible Human dataset, giving a bicubic finite element skin mesh and discrete sentinel lymph node model. The full dataset of 2D melanoma site coordinates, excluding the head and neck, has been transformed onto this 3D skin mesh via free-form deformation and projection techniques. Sentinel lymph nodes were mapped onto the generic lymph node model for each patient. Preliminary spatial analysis indicates that a patient with a primary melanoma on the torso around the waist (on the standardized 3D model this region is 180 mm above and 130 mm below the umbilicus) with lymphatic drainage to the left axilla or left groin, will have a 17.7% probability of dual drainage to both node fields, with 95% confidence limits between 14.5 and 21.0%. PMID:17453347

Reynolds, Hayley M; Dunbar, P Rod; Uren, Roger F; Thompson, John F; Smith, Nicolas P

2007-08-01

93

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

Science.gov (United States)

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 connectivity to the striatum. We found that a dorsomedial region of the SN/VTA preferentially connected to the ventral striatum whereas a more ventrolateral region connected to the dorsal striatum. These SN/VTA subregions could be characterised by differences in quantitative structural imaging parameters, suggesting different underlying tissue properties. We also observed that these connectivity patterns differentially mapped onto reward dependence personality trait. We show that tractography can be used to parcellate the SN/VTA into anatomically plausible and behaviourally meaningful compartments, an approach that may help future studies to provide a more fine-grained synopsis of pathological changes in the dopaminergic midbrain and their functional impact. PMID:23684858

Chowdhury, Rumana; Lambert, Christian; Dolan, Raymond J; Düzel, Emrah

2013-11-01

94

Symmetry and appearance based automated detection of salient anatomical regions in ultrasound.  

Science.gov (United States)

In this paper we present a method for automated detection of enclosed anatomical regions in ultrasound images by utilizing the coarse shape symmetry as well as relative homogeneity of their sonographic appearance. The proposed method comprises of two steps: First, local phase based filtering [2] is used to detect points in the image which are roughly positioned along the axes of spatial symmetry with respect to structures around them. Secondly, the sonographic 'appearance' and location of these points is used to define a distance-map on the image, which is supplied to a simple fast-marching algorithm in order to provide the final feature detections. The method is robust to ultrasound speckle and works well with or without specialized pre-processing (e.g. speckle-reduction filtering). We illustrate the proposed method with qualitative results on in-vivo Ultrasound images. PMID:23366909

Patwardhan, Kedar A

2012-01-01

95

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

96

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

97

The incidence of invasion and metastasis of nasopharyngeal carcinoma at different anatomic sites in the skull base.  

Science.gov (United States)

This study aimed to investigate the incidence of direct invasion and metastasis of nasopharyngeal carcinoma (NPC) at different anatomic sites in the skull base using magnetic resonance imaging (MRI). MRI data from 101 NPC patients with skull base invasion were collected and we analyzed the incidence and anatomic sites of invasion of NPC in the skull base. Of the 101 NPC patients, 84 had direct invasion at the skull base (83.2%), and 17 had skull base metastasis (16.8%). Affected sites with direct invasion in the skull base included sphenoid sinus and sella base, cavernous sinus, internal carotid canal, and clivus blumenbachii. Skull base metastasis sites included the internal carotid canal and jugular foramen area. Because of early lymphatic metastasis of NPC to the skull base, MRI examination can be helpful in increasing the accuracy of diagnostic imaging for skull base invasion of NPC and selecting appropriate target sites, radiotherapy techniques, and operative approaches. PMID:22692884

Han, Jun; Zhang, Qiuhang; Kong, Feng; Gao, Yongan

2012-08-01

98

Acquistion of Structural versus Object Landmark Knowledge  

Science.gov (United States)

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

Stankiewicz, Brian J.; Kalia, Amy A.

2007-01-01

99

Segmentation of anatomical branching structures based on texture features and conditional random field  

Science.gov (United States)

This work is a part of our ongoing study aimed at understanding a relation between the topology of anatomical branching structures with the underlying image texture. Morphological variability of the breast ductal network is associated with subsequent development of abnormalities in patients with nipple discharge such as papilloma, breast cancer and atypia. In this work, we investigate complex dependence among ductal components to perform segmentation, the first step for analyzing topology of ductal lobes. Our automated framework is based on incorporating a conditional random field with texture descriptors of skewness, coarseness, contrast, energy and fractal dimension. These features are selected to capture the architectural variability of the enhanced ducts by encoding spatial variations between pixel patches in galactographic image. The segmentation algorithm was applied to a dataset of 20 x-ray galactograms obtained at the Hospital of the University of Pennsylvania. We compared the performance of the proposed approach with fully and semi automated segmentation algorithms based on neural network classification, fuzzy-connectedness, vesselness filter and graph cuts. Global consistency error and confusion matrix analysis were used as accuracy measurements. For the proposed approach, the true positive rate was higher and the false negative rate was significantly lower compared to other fully automated methods. This indicates that segmentation based on CRF incorporated with texture descriptors has potential to efficiently support the analysis of complex topology of the ducts and aid in development of realistic breast anatomy phantoms.

Nuzhnaya, Tatyana; Bakic, Predrag; Kontos, Despina; Megalooikonomou, Vasileios; Ling, Haibin

2012-02-01

100

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

 
 
 
 
101

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.)

102

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

103

Geographic Surveillance - Landmark Studies  

Science.gov (United States)

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

104

Live-wire-based segmentation of 3D anatomical structures for image-guided lung interventions  

Science.gov (United States)

Computed Tomography (CT) has been widely used for assisting in lung cancer detection/diagnosis and treatment. In lung cancer diagnosis, suspect lesions or regions of interest (ROIs) are usually analyzed in screening CT scans. Then, CT-based image-guided minimally invasive procedures are performed for further diagnosis through bronchoscopic or percutaneous approaches. Thus, ROI segmentation is a preliminary but vital step for abnormality detection, procedural planning, and intra-procedural guidance. In lung cancer diagnosis, such ROIs can be tumors, lymph nodes, nodules, etc., which may vary in size, shape, and other complication phenomena. Manual segmentation approaches are time consuming, user-biased, and cannot guarantee reproducible results. Automatic methods do not require user input, but they are usually highly application-dependent. To counterbalance among efficiency, accuracy, and robustness, considerable efforts have been contributed to semi-automatic strategies, which enable full user control, while minimizing human interactions. Among available semi-automatic approaches, the live-wire algorithm has been recognized as a valuable tool for segmentation of a wide range of ROIs from chest CT images. In this paper, a new 3D extension of the traditional 2D live-wire method is proposed for 3D ROI segmentation. In the experiments, the proposed approach is applied to a set of anatomical ROIs from 3D chest CT images, and the results are compared with the segmentation derived from a previous evaluated live-wire-based approach.

Lu, Kongkuo; Xu, Sheng; Xue, Zhong; Wong, Stephen T.

2012-02-01

105

Anatomic feature-based registration for patient set-up in head and neck cancer radiotherapy  

Energy Technology Data Exchange (ETDEWEB)

Modern radiotherapy equipment is capable of delivering high precision conformal dose distributions relative to isocentre. One of the barriers to precise treatments is accurate patient re-positioning before each fraction of treatment. At Massachusetts General Hospital, we perform daily patient alignment using radiographs, which are captured by flat panel imaging devices and sent to an analysis program. A trained therapist manually selects anatomically significant features in the skeleton, and couch movement is computed based on the image coordinates of the features. The current procedure takes about 5 to 10 min and significantly affects the efficiency requirement in a busy clinic. This work presents our effort to develop an improved, semi-automatic procedure that uses the manually selected features from the first treatment fraction to automatically locate the same features on the second and subsequent fractions. An implementation of this semi-automatic procedure is currently in clinical use for head and neck tumour sites. Radiographs collected from 510 patient set-ups were used to test this algorithm. A mean difference of 1.5 mm between manual and automatic localization of individual features and a mean difference of 0.8 mm for overall set-up were seen.

Sharp, Gregory C; Kollipara, Sashidhar; Madden, Thomas; Jiang, Steve B; Rosenthal, Stanley J [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114 (United States)

2005-10-07

106

The study of femoral 3D reconstruction process based on anatomical parameters using a numerical method  

International Nuclear Information System (INIS)

Computer based three-dimensional (3D) reconstruction technique is widely used in clinical practices and its accuracy is still improving due to introducing of high resolution imaging modalities. Practically, two-dimensional X-ray image might be considered as one of major tools in orthopaedics, due to its lower cost and lower dose of radiation than computer tomography (CT). The purpose of the current study is generating 3D model of femoral bone using conventional X-ray images incorporating the anatomical parameters into a referential 3D model. For the 3D reconstruction, the 2D shape and specific parameters of bone were firstly measured from X-ray images. Then, the referential CT model was modified as follows: the axial scaling, shearing transformation and radial scaling. In this study, the 3D reconstruction algorithm was tested using femoral X-ray images from the 28 years old male. The current study showed that the 3D reconstruction technique by using X-ray images can be useful and feasible in clinical practices. It could easily generate 3D femoral model not only with saving time and costs, but also less radiation exposure to the patients. (author)

107

A combined anatomic and electrophysiologic substrate based approach for sudden cardiac death risk stratification  

Science.gov (United States)

Background Although left ventricle ejection fraction (LVEF) is the primary determinant for sudden cardiac death (SCD) risk stratification, in isolation, LVEF is a sub-optimal risk stratifier. We assessed whether a multi-marker strategy would provide more robust SCD risk stratification than LVEF alone. Methods We collected patient-level data (n=3355) from 6 studies assessing the prognostic utility of microvolt T-wave alternans (MTWA) testing. Two-thirds of the group was used for derivation (n=2242) and one-third for validation (n=1113). The discriminative capacity of the multivariable model was assessed using the area under the receiver-operating characteristic (ROC) curve (c-index). The primary endpoint was SCD at 24 months. Results In the derivation cohort, 59 patients experienced SCD by 24 months. Stepwise selection suggested that a model based on 3 parameters (LVEF, coronary artery disease [CAD] and MTWA status) provided optimal SCD risk prediction. In the derivation cohort, the c-index of the model was 0.817, which was significantly better than LVEF used as a single variable (0.637, p < 0.001). In the validation cohort, 36 patients experienced SCD by 24 months. The c-index of the model for predicting the primary endpoint was again significantly better than LVEF alone (0.774 vs. 0.671, p = 0.020). Conclusions A multivariable model based on presence of CAD, LVEF and MTWA status provides significantly more robust SCD risk prediction than LVEF as a single risk marker. These findings suggest that multi-marker strategies based on different aspects of the electro-anatomic substrate may be capable of improving primary prevention ICD treatment algorithms. PMID:24093856

Merchant, Faisal M.; Zheng, Hui; Bigger, Thomas; Steinman, Richard; Ikeda, Takanori; Pedretti, Roberto F.E.; Salerno-Uriarte, Jorge A.; Klersy, Catherine; Chan, Paul S.; Bartone, Cheryl; Hohnloser, Stefan H.; Ruskin, Jeremy N.; Armoundas, Antonis A.

2014-01-01

108

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

Scientific Electronic Library Online (English)

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

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

2006-12-01

109

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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, B...

MUH RAHMAD SUHARTANTO; SOBIR; ALFIN WIDIASTUTI

2010-01-01

110

Anatomical-functional image correlation problem: an interactive tool based on a hybrid method  

Science.gov (United States)

The accurate localization of anatomical structures in functional images is a crucial point in positron emission tomography (PET) studies, due to the relatively poor spatial resolution in PET and to the strict dependence from the metabolic behavior of the used tracer. Until now, mainly two software approaches to the solution of the above problem have been used: the automatic match of PET images with a corresponding anatomical image, and the use of a computerized atlas of brain anatomical structures. The decision to adopt a `hybrid' method, allowing the users to rely on automatic image matching and, at the same time, also being able to intervene at any moment in the anatomic localization process, has led to the development of a user-friendly, interactive image processing tool, including a computer driven correlation process and a set of general-purpose image processing routines. The package, called CHIP (correlative hybrid image processing tool), has been implemented in C on a SUN 3/60 graphic workstation, with X11-R4 window system, using the XView toolkit (from OpenLook) to build the user-interface, and will soon be ported on a SUN SPARC-II workstation, with the aim of enhancing its performance. The correlation is implemented by extracting contours from the image obtained performing an anatomical scan (CT or MRI) of the patient, using a physical head-holder to match the PET slice, and transforming the contour image into a set of significant regions of interest (ROIs); these can undergo additional editing by the user to correct possible inaccuracies generated by the automated edge-finding process. CHIP is able to perform a lot of general-purpose image utilities, including: (1) Spatial filtering -- e.g., smoothing, edge crispening, median filtering, convolution with user-defined filter; and (2) Histogram package -- histogram drawing, automatic equalization, user-friendly manual histogram, rescaling and cutting. This package, together with the former, permits the user to enhance anatomical images. This is particularly important when using CT images that typically, especially in the brain cortex, show a contrast inadequate for detecting small cerebral structures.

Pisani, Patrizia; Guzzardi, Riccardo; Bellina, C. R.; Sorace, O.

1992-06-01

111

Retrosplenial Cortex Codes for Permanent Landmarks  

Science.gov (United States)

Landmarks are critical components of our internal representation of the environment, yet their specific properties are rarely studied, and little is known about how they are processed in the brain. Here we characterised a large set of landmarks along a range of features that included size, visual salience, navigational utility, and permanence. When human participants viewed images of these single landmarks during functional magnetic resonance imaging (fMRI), parahippocampal cortex (PHC) and retrosplenial cortex (RSC) were both engaged by landmark features, but in different ways. PHC responded to a range of landmark attributes, while RSC was engaged by only the most permanent landmarks. Furthermore, when participants were divided into good and poor navigators, the latter were significantly less reliable at identifying the most permanent landmarks, and had reduced responses in RSC and anterodorsal thalamus when viewing such landmarks. The RSC has been widely implicated in navigation but its precise role remains uncertain. Our findings suggest that a primary function of the RSC may be to process the most stable features in an environment, and this could be a prerequisite for successful navigation. PMID:22912894

Auger, Stephen D.; Mullally, Sinead L.; Maguire, Eleanor A.

2012-01-01

112

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

113

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

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

2012-01-01

114

Probabilistic MRI Brain Anatomical Atlases Based on 1,000 Chinese Subjects  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Brain atlases are designed to provide a standard reference coordinate system of the brain for neuroscience research. Existing human brain atlases are widely used to provide anatomical references and information regarding structural characteristics of the brain. The majority of them, however, are derived from one paticipant or small samples of the Western population. This poses a limitation for scientific studies on Eastern subjects. In this study, 10 new Chinese brain atlases f...

Xing, Wang; Nan, Chen; Zhentao, Zuo; Rong, Xue; Luo, Jing; Zhuo, Yan; Dinggang, Shen; Kuncheng, Li

2013-01-01

115

Removal of normal anatomic structures in radiographs using wavelet-based nonlinear variational method for image matching  

Science.gov (United States)

A wavelet-based image matching method was developed for removal of normal anatomic structures in chest radiographs for reduction of false positives reported by our computer- aided diagnosis (CAD) scheme for detection of lung nodules. In our approach, two regions of interest (ROIs) are extracted, one from the position where a candidate of a nodule is located, and the other from the position located at a point symmetric to the first position relative to the spine. The second ROI contains normal anatomic structures similar to those of the first ROI. A non-linear functional representing the squared differences between the two images is formulated, and is minimized by a coarse-to-fine approach to yield a planar mapping that matches the two similar images. A smoothing term is added to the non-linear functional, which penalizes discontinuous and irregular mappings. If no structure remains in the difference between these matched images, then the first ROI is identified to be a false detection (i.e., it contains only normal structures); otherwise, it is regarded as a nodule (i.e., it contains an abnormal structure). A preliminary result shows that our method is effective in removing normal anatomic structures and thus is useful for substantially reducing the number of false detections in our CAD scheme.

Yoshida, Hiroyuki

1998-10-01

116

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

117

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2014-02-15

118

Origin of the anterior cruciate ligament and the surrounding osseous landmarks of the femur.  

Science.gov (United States)

The aims of this study were to evaluate the discernibility of the LIR (lateral intercondylar ridge) and the LBR (lateral bifurcate ridge) and show their reliability in femoral tunnel placement in ACL (anterior cruciate ligament) reconstruction. Additionally, their position to the femoral axis, their course, and the ACL footprint were analyzed. For this study, 235 human femora were evaluated. Of these, 166 specimens originated from the Museum of Natural History (group A), and 69 were obtained from fixed cadavers at the Anatomic Institute (group B). The femoral footprint and the osseous landmarks were identified macroscopically and labeled in the photographs. A coordinate system was outlined, and the dimensions, position, and orientation of the femoral footprint of the ACL were measured. The LBR was found in 24.7% of the specimens in group A and in only 13.2% of the specimens in group B. The LIR was found in 97.9% and 85.3% of the specimens in groups A and B, respectively. The area of the ACL footprint was 127.21?±?32.54 mm(2) in group A and 119.58?±?34.84 mm(2) in group B. The shapes and angles of the osseous landmarks near the line of Blumensaat were highly variable. The LBR is an unreliable intraoperative landmark for arthroscopic ACL reconstruction due to its low incidence. Other anatomical structures, such as the LIR or the osteochondral border, may be more helpful and reliable landmarks to guide proper tunnel placement. PMID:25065356

Zauleck, Max Konstantin; Gabriel, Sebastian; Fischmeister, Martin Franz; Hirtler, Lena

2014-10-01

119

Muscle fibre direction of longissimus, iliocostalis and multifidus: landmark-derived reference lines.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Considerable inter-individual variations in the fibre direction angles of the iliocostalis lumborum, longissimus and multifidus were observed, thus bringing the applicability of a two dimensional fixed angle grid system for fibre direction determination into question. However, the angulation of the fibres of the multifidus and iliocostalis lumborum were found to be easily identifiable by the use of three surface anatomical landmarks: the caudal tip of the superior iliac spine, the lateral bor...

Foa, J. L.; Forrest, W.; Biedermann, H. J.

1989-01-01

120

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

 
 
 
 
121

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

122

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

Directory of Open Access Journals (Sweden)

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

Ivy Kiemle Trindade-Suedam

2012-02-01

123

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

Energy Technology Data Exchange (ETDEWEB)

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.

Castillo, Richard [Department of Imaging Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Castillo, Edward [Department of Mathematics, University of California, Irvine, CA (United States); Guerra, Rudy [Department of Statistics, Rice University, Houston, TX (United States); Johnson, Valen E [Department of Biostatistics and Applied Mathematics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); McPhail, Travis [Department of Computer Science, Rice University, Houston, TX (United States); Garg, Amit K; Guerrero, Thomas [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States)], E-mail: tguerrero@mdanderson.org

2009-04-07

124

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.

125

Automatic landmarking of cephalograms using active appearance models.  

Science.gov (United States)

There have been many attempts to further improve and automate cephalometric analysis in order to increase accuracy, reduce errors due to subjectivity, and to provide more efficient use of clinicians' time. The aim of this research was to evaluate an automated system for landmarking of cephalograms based on the use of an active appearance model (AAM) that contains a statistical model of shape and grey-level appearance of an object of interest and represents both shape and texture variations of the region covered by the model. Multi-resolution implementation was used, in which the AAM iterate to convergence at each level before projecting the current solution to the next level of the model. The AAM system was trained using 60 randomly selected, hand-annotated digital cephalograms of subjects between 7.2 and 25.6 years of age, and tested with a leave-five-out method that enabled testing not only of the accuracy of the AAM system but also the accuracy of each AAM. Differences between methods were examined using the non-parametric Wilcoxon signed rank test. An average accuracy of 1.68 mm was obtained, with 61 per cent of landmarks detected within 2 mm and 95 per cent of landmarks detected within 5 mm precision. A noticeable increase in overall precision and detection of low-contrast cephalometric landmarks was achieved compared with other automated systems. These results suggest that the AAM approach can adequately represent the average shape and texture variations of craniofacial structures on digital radiographs. As such it can successfully be implemented for automatic localization of cephalometric landmarks. PMID:20203126

Vucini?, Predrag; Trpovski, Zeljen; S?epan, Ivana

2010-06-01

126

The test-retest reliability of anatomical co-ordinate axes definition for the quantification of lower extremity kinematics during running.  

Science.gov (United States)

Three-dimensional (3-D) kinematic analyses are used widely in both sport and clinical examinations. However, this procedure depends on reliable palpation of anatomical landmarks and mal-positioning of markers between sessions may result in improperly defined segment co-ordinate system axes which will produce in-consistent joint rotations. This had led some to question the efficacy of this technique. The aim of the current investigation was to assess the reliability of the anatomical frame definition when quantifying 3-D kinematics of the lower extremities during running. Ten participants completed five successful running trials at 4.0 m·s(-1) ± 5%. 3-D angular joint kinematics parameters from the hip, knee and ankle were collected using an eight camera motion analysis system. Two static calibration trials were captured. The first (test) was conducted prior to the running trials following which anatomical landmarks were removed. The second was obtained following completion of the running trials where anatomical landmarks were re-positioned (retest). Paired samples t-tests were used to compare 3-D kinematic parameters quantified using the two static trials, and intraclass correlations were employed to examine the similarities between the sagittal, coronal and transverse plane waveforms. The results indicate that no significant (p>0.05) differences were found between test and retest 3-D kinematic parameters and strong (R(2)?0.87) correlations were observed between test and retest waveforms. Based on the results obtained from this investigation, it appears that the anatomical co-ordinate axes of the lower extremities can be defined reliably thus confirming the efficacy of studies using this technique. PMID:23487393

Sinclair, Jonathan; Taylor, Paul John; Greenhalgh, Andrew; Edmundson, Christopher James; Brooks, Darrell; Hobbs, Sarah Jane

2012-12-01

127

Landmarks selection in street map design  

Science.gov (United States)

In Taiwan many electrical maps present their landmarks according to the category of the feature, a designer short of knowledge about mental representation of space, can cause the map to lose its communication effects. To resolve this map design problem, in this research through long-term memory recall, navigation and observation, and short-term memory processing 111 participants were asked to select the proper landmark from study area. The results reveal that in Taiwan convenience stores are the most popular local landmark in rural and urban areas. Their commercial signs have a unique design and bright color. Contrasted to their background, this makes the convenience store a salient feature. This study also developed a rule to assess the priority of the landmarks to design them in different scale maps.

Kao, C. J.

2014-02-01

128

75 FR 69120 - National Natural Landmark Designations  

Science.gov (United States)

...Landmarks: Big Bone Lick, Boone County, Kentucky; Cave Without a Name, Kendall County, Texas; Chazy Fossil Reef...e., Federal, State, county or municipal governments...located within the State of Kentucky, southwest of...

2010-11-10

129

From objects to landmarks: the function of visual location information in spatial navigation  

Directory of Open Access Journals (Sweden)

Full Text Available Landmarks play an important role in guiding navigational behavior. A host of studies in the last 15 years has demonstrated that environmental objects can act as landmarks for navigation in different ways. In this review, we propose a parsimonious four-part taxonomy for conceptualizing object location information during navigation. We begin by outlining object properties that appear to be important for a landmark to attain salience. We then systematically examine the different functions of objects as navigational landmarks based on previous behavioral and neuroanatomical findings in rodents and humans. Evidence is presented showing that single environmental objects can function as navigational beacons, or act as associative or orientation cues. In addition, we argue that extended surfaces or boundaries can act as landmarks by providing a frame of reference for encoding spatial information. The present review provides a concise taxonomy of the use of visual objects as landmarks in navigation and should serve as a useful reference for future research into landmark-based spatial navigation.

OliverBaumann

2012-08-01

130

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

131

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

International Nuclear Information System (INIS)

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

132

Interoperator test for anatomical annotation of earprints.  

Science.gov (United States)

As part of the Forensic Ear Identification (FearID) research project, which aims to obtain estimators for the strength of evidence of earmarks found on crime scenes, a large database of earprints (over 1200 donors) has been collected. Starting from a knowledge-based approach where experts add anatomical annotations of minutiae and landmarks present in prints, comparison of pairs of prints is done using the method of Vector Template Matching (VTM). As the annotation process is subjective, a validation experiment was performed to study its stability. Comparing prints on the basis of VTM, it appears that there are interoperator effects, individual operators yielding significantly more consistent results when annotating prints than different operators. The operators being well trained and educated, the observed variation on both clicking frequency and choice of annotation points suggests that implementation of the above is not the best way to go about objectifying earprint comparison. Processes like the above are relevant for any forensic science dealing with identification (e.g., of glass, tool marks, fibers, faces, fingers, handwriting, speakers) where manual (nonautomated) processes play a role. In these cases, results may be operator dependent and the dependencies need to be studied. PMID:17199610

Alberink, Ivo B; Ruifrok, Arnout C C; Kieckhoefer, Hartmut

2006-11-01

133

Brain mapping in stereotactic surgery: a brief overview from the probabilistic targeting to the patient-based anatomic mapping.  

Science.gov (United States)

In this article, we briefly review the concept of brain mapping in stereotactic surgery taking into account recent advances in stereotactic imaging. The gold standard continues to rely on probabilistic and indirect targeting, relative to a stereotactic reference, i.e., mostly the anterior (AC) and the posterior (PC) commissures. The theoretical position of a target defined on an atlas is transposed into the stereotactic space of a patient's brain; final positioning depends on electrophysiological analysis. The method is also used to analyze final electrode or lesion position for a patient or group of patients, by projection on an atlas. Limitations are precision of definition of the AC-PC line, probabilistic location and reliability of the electrophysiological guidance. Advances in MR imaging, as from 1.5-T machines, make stereotactic references no longer mandatory and allow an anatomic mapping based on an individual patient's brain. Direct targeting is enabled by high-quality images, an advanced anatomic knowledge and dedicated surgical software. Labeling associated with manual segmentation can help for the position analysis along non-conventional, interpolated planes. Analysis of final electrode or lesion position, for a patient or group of patients, could benefit from the concept of membership, the attribution of a weighted membership degree to a contact or a structure according to its level of involvement. In the future, more powerful MRI machines, diffusion tensor imaging, tractography and computational modeling will further the understanding of anatomy and deep brain stimulation effects. PMID:17644002

Lemaire, Jean-Jacques; Coste, Jérôme; Ouchchane, Lemlih; Caire, François; Nuti, Christophe; Derost, Philippe; Cristini, Vittorio; Gabrillargues, Jean; Hemm, Simone; Durif, Franck; Chazal, Jean

2007-01-01

134

Anatomical deficits in adult posttraumatic stress disorder: a meta-analysis of voxel-based morphometry studies.  

Science.gov (United States)

Evidence from previous anatomical studies indicate that widespread brain regions are involved in the pathogenesis of posttraumatic stress disorder (PTSD). The aim of the present study was to quantitatively integrate the literature on structural abnormalities seen on individuals with PTSD. Twenty voxel-based analysis studies were analysed through a comprehensive series of meta-analyses. Compared with healthy controls, PTSD patients showed a significant reduction in grey matter (GM) in the left anterior cingulate gyrus (ACC) at the whole-brain level. Several brain regions, including the left ACC, the left insula and the right parahippocampal gyrus were significantly smaller in individuals with PTSD than in trauma-exposed healthy subjects. Furthermore, the clinician-administered PTSD scale scores were negatively correlated with GM in the left ACC and positively correlated with GM in the left insula. In addition, PTSD patients who experienced accidental or non-accidental trauma had anatomical changes in different brain regions. These results suggest that the smaller ACC and insular cortex within the limbic-prefrontal circuit contribute to the pathogenesis of PTSD. Moreover, the PTSD patients with different types of trauma may have different cerebral deficits. PMID:24859173

Meng, Yajing; Qiu, Changjian; Zhu, Hongru; Lama, Sunima; Lui, Su; Gong, Qiyong; Zhang, Wei

2014-08-15

135

'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

136

Color-contrast landmark detection and encoding in outdoor images  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Todt, Eduardo; Torras Geni?s, Carme

2005-01-01

137

Repeatability and reproducibility of landmarks--a three-dimensional computed tomography study.  

Science.gov (United States)

The aim of this study was to investigate the repeatability and reproducibility of the placement of anthropological cephalometric landmarks on three-dimensional computed tomography (3D CT) cranial reconstructions derived from volume data sets. In addition, the influence of the observer's experience on the repeatability of landmark setting was also explored. Twenty patients without any craniofacial deformity (11 females and 9 males; age range 6.1-16 years) were selected retrospectively from CT volume data sets already available from 695 patients of Dental Clinic 3, Orthodontics of Erlangen University Hospital. The CT examination was performed with the SOMATOM Sensation64 (Siemens AG Medical Solutions, Erlangen, Germany). The program VoXim6.1 (IVS Solutions AG, Chemnitz, Germany) was used for 3D reconstruction of the volume data sets. A total of 28 landmarks were examined in the skeleton module of the program VoXim6.1. The randomly sorted data sets were analysed by two orthodontists and two postgraduate students. Each data set was analysed twice by each observer at an interval of 3 weeks. The analysis of variance regarding random effects was used to calculate the intraobserver and interobserver components of standard deviation (SD) of depiction of individual landmarks as measures of repeatability and reproducibility, respectively. Median intraserial SD and interserial SD of 0.46 mm (range: 0.14-2.00 mm) and 0.20 mm (range: 0.02-2.47 mm), respectively, were obtained depending on the landmark and plane. This study included systematic analysis of extreme values (outliers) in the assessment of the quality of measurements obtained. Descriptive statistics revealed qualitative differences in the depiction of different landmarks. The landmarks nasion and infradentale revealed a minor SD in all three spatial coordinates with the smallest SD for infradentale (SD = 0.18 mm) in the transverse plane. However, no systematic trend was identified with regard to the influence of the observer's level of experience affecting the repeatability of landmark positioning. Thus, the repeatability and reproducibility of placements of landmarks with 3D CT were found to be acceptable for a majority of anatomical positions. PMID:21566086

Titiz, Irem; Laubinger, Michala; Keller, Thomas; Hertrich, Klaus; Hirschfelder, Ursula

2012-06-01

138

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

139

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

140

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

 
 
 
 
141

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

Science.gov (United States)

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

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

2000-06-01

142

Posterior condylar canals and posterior condylar emissary veins-a microsurgical and CT anatomical study.  

Science.gov (United States)

The posterior condylar canals (PCCs) and posterior condylar emissary veins (PCEVs) are potential anatomical landmarks for surgical approaches through the lateral foramen magnum. We conducted computed tomography (CT) and microsurgical investigation of how PCCs and PCEVs can aid in planning and performing these approaches. We analyzed the microanatomy of PCCs and PCEVs using cadaveric specimens, dry skulls, and CT images. The recognition frequency and geometry of PCCs and PCEVs and their relationships with surrounding structures were evaluated. PCCs were identified in 36 of 50 sides in dry bones and 82 of 100 sides by CT. PCCs had a 3.5-mm mean diameter and a 6.8-mm mean canal length. We classified their courses into four types according to intracranial openings: the sigmoid sinus (SS) type, the jugular bulb (JB) type, the occipital sinus type, and the anterior condylar emissary vein type. In most cases, PCEV originated near the boundary between the SS and JB. PCCs and PCEVs can be useful anatomical landmarks to differentiate the transcondylar fossa approach from the transcondylar approach, thus preventing unnecessary injury of the atlantooccipital joint. They can also be used as landmarks when the jugular foramen (JF) and hypoglossal canal (HGC) are being exposed. The area anterior to the brain stem and the medial part of HGC can be accessed by removal of the lateral foramen magnum medial to PCC. JF and the lateral part of HGC can be accessed by removal of the skull base lateral to PCC without damaging the lateral rim of the foramen magnum. PMID:23996282

Matsushima, Ken; Kawashima, Masatou; Matsushima, Toshio; Hiraishi, Tetsuya; Noguchi, Tomoyuki; Kuraoka, Akio

2014-01-01

143

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

Science.gov (United States)

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 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.

Tinniswood, A. D.; Furse, C. M.; Gandhi, O. P.

1998-08-01

144

Landmark advances in the development of erythropoietin.  

Science.gov (United States)

This is a Minireview covering landmarks or milestones in the development of erythropoietin (EPO). Thirty-nine landmark advances have been identified, which cover the period 1863-2003. Several reports are included that directly support these original landmark advances. This Minireview also updates some of the advances in EPO research since my last Minireview update on EPO published in this journal in 2003. The areas of EPO research updated are: sites of production; purification, assay and standardization; regulation; action; use in anemias; extraerythropoietic actions; adverse effects; and blood doping. The new reports on the use of EPO in the therapy of myocardial infarction; stroke and other neurological diseases; diabetic retinopathy and other retinal diseases are also covered. PMID:21127338

Fisher, James W

2010-12-01

145

Bases Anatómicas de la Gluteoplastía Dinámica / Anatomical Basis of the Dinamic Gluteoplaty  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish La disrupción anatómica del esfínter es el mecanismo más común de incontinencia fecal. La creación de un mecanismo esfinteriano con control voluntario permite mantener la contracción en el reposo o durante los movimientos y es uno de los principios fisiológicos y quirúrgicos para la continencia. Est [...] a corrección puede realizarse mediante la transposición de músculo glúteo mayor alrededor del ano y recrear así un esfínter voluntario. La gluteoplastía dinámica consiste en la colocación de un marcapasos que permite la estimulación eléctrica crónica intermitente del músculo esquelético, resultando en la adaptación de la contractilidad basal. El objetivo del trabajo consiste en el estudio anatómico de la longitud in situ y esqueletizado del fascículo inferior del músculo glúteo máximo, de su principal pedículo nervioso, la altura en la cual penetra al músculo desde el cóccix, y la longitud de su rama más distal para finalmente, proponer variantes técnicas para este procedimiento. Se disecaron 21 regiones glúteas de ambos lados de cadáveres frescos y formolizados al 10% de ambos sexos. La longitud del fascículo muscular sin esqueletizar osciló entre 17,8 y 19,65 cm, y esqueletizado entre 23,9 y 20.7 cm. La distancia de penetración del nervio principal fue entre 11,25 10,2 cm y la del nervio más medial se situó promedialmente entre 8,72 y 5,97 cm. La máxima longitud adquirida por el nervio principal hasta su rama más distal, osciló entre 10,4 y 9,2 cm. El fascículo inferior posee una longitud final que permite rodear completamente al ano e incluso, llegar al isquion contralateral hechos que apoyan el uso de este músculo en las transposiciones para la corrección de las incontinencias anales, sin la necesidad de realizar abordajes desmedidos y lejanos, permitiendo a su vez, el uso de un músculo de la región, evitando tracciones del pedículo neurovascular y la consiguiente isquemia luego del procedimiento quirúrgico. Se proponen tres técnicas para la rotación del colgajo Abstract in english The anatomical disruption of the sphincter is the most common mechanism of fecal incontinence. The creation of an sphincter mechanism with voluntary control allows to maintain the contraction during rest or movements and is one of the physiological and surgical principles of continence. This correct [...] ion can be made by the gluteus maximus muscle transposition around the anus recreating a voluntary sphincter. The dynamic gluteoplasty consists in the positioning of a nerve stimulator that allows the intermittent chronic electrical stimulation of the skeletal muscle resulting in the adaptation of the basal contractility. The objective of the work is the anatomic study of the inferior fascicle of the gluteus maximus muscle (its length in situ and squeletized) and of its main nervous pedicle (the height in which penetrates the muscle from coccyx, and the length of its distal branch) so as to propose technical changes for the procedure. Twenty and one gluteus regions of both sides from fresh and formalized cadavers of both sexes were dissected. The length of muscular fascicle without squeletized oscillated between 17.8 and 19.65 cm, and squeletized between 23.9 and 20.7 cm. The distance of penetration of the main nerve was between 11.25 and 10.2 cm and the one of the most internal nerve was located promedially between 8.72 and 5.97 cm. The maximun length acquired by the main nerve until its distal branch oscillated between 10.4 and 9.2 cm. The inferior fascicle has a final length that allows to surround completely the anus or even to reach the contralateral isquion, facts which support the use of this muscle in the transpositions for the correction of the anal incontinence, without making excessive or distant boardings, allowing as well the use of a muscle from the region, avoiding tractions of neurovascular pedicle and the consequent isquemia after the surgical procedure. Three technical changes for the rotation of

Laura, Borgno; Varinia, Scanniello; Omar, Rompani; Alejandra, Laxague; Sofía, Páez.

146

An ethanol-based fixation method for anatomical and micro-morphological characterization of leaves of various tree species.  

Science.gov (United States)

The use of formalin constitutes serious health hazards for laboratory workers. We investigated the suitability and performance of the ethanol-based fixative, FineFIX, as a substitute for formalin for anatomical and cellular structure investigations of leaves by light microscopy and for leaf surface and ultrastructural analysis by scanning electron microscopy (SEM). We compared the anatomical features of leaf materials prepared using conventional formalin fixation with the FineFIX. Leaves were collected from ornamental tree species commonly used in urban areas. FineFIX was also compared with glutaraldehyde fixation and air drying normally used for scanning electron microscopy to develop a new method for evaluating leaf morphology and microstructure in three ornamental tree species. The cytological features of the samples processed for histological analysis were well preserved by both fixatives as demonstrated by the absence of nuclear swelling or shrinkage, cell wall detachment or tissue flaking, and good presentation of cytoplasmic vacuolization. In addition, good preservation of surface details and the absence of shrinkage artefacts confirmed the efficacy of FineFIX fixation for SEM analysis. Cuticular wax was preserved only in air dried samples. Samples treated with chemical substances during the fixation and dehydration phases showed various alterations of the wax structures. In some air dried samples a loss of turgidity of the cells was observed that caused general wrinkling of the epidermal surfaces. Commercial FineFIX is an adequate substitute for formalin in histology and it can be applied successfully also for SEM investigation, while reducing the health risks of glutaraldehyde or other toxic fixatives. To investigate the potential for plants to absorb and capture particulates in air, which requires preservation of the natural morphology of trichomes and epicuticular waxes, a combination of FineFIX fixation and air drying is recommended. PMID:23244233

Chieco, C; Rotondi, A; Morrone, L; Rapparini, F; Baraldi, R

2013-02-01

147

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

148

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

149

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

Energy Technology Data Exchange (ETDEWEB)

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.)

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

2009-02-15

150

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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.

Kruglova, Natalia N.

2013-01-01

151

36 CFR 62.6 - Natural landmark monitoring.  

Science.gov (United States)

... false Natural landmark monitoring. 62.6 Section 62...62.6 Natural landmark monitoring. (a) Owner contact...Offices of the NPS maintain periodic contacts with the owners...Offices are responsible for monitoring the condition of,...

2010-07-01

152

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

153

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

Science.gov (United States)

...the Landmark Legal Foundation. [[Page 49976...Reconsideration Landmark Legal Foundation (``Landmark...and existing power plants. See Justin Sink...Power Co. v. Nuclear Regulatory Com...everything from power plants to the Keystone...President Landmark Legal Foundation, 19415...

2013-08-16

154

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

155

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. Am. J. Hematol. 89:943-946, 2014. © 2014 Wiley Periodicals, Inc. 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

156

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

157

Anatomic and magnetic resonance imaging bases for the naso-maxillo-cheek flap technique.  

Science.gov (United States)

A transfacial approach to the deep cranio-maxillo-facial areas by the naso-maxillo-cheek flap technique (NMCF) is indicated for the treatment of some bulky tumors of the naso-pharynx. The procedure requires precise preoperative imaging. This study presents the morphologic bases of this surgical access and the reasonable limits of the excision preoperatively determined by magnetic resonance imaging (MRI). 18 facial and skull specimens were submitted to surgical facial dismantling by the NMCF technique according to Curioni's method. The clinical application in a 66-year-old patient suffering from a neuroblastoma of the olfactory nerve extended into the naso-pharynx is presented. Pre- and postoperative MRI correlations were made in transverse, sagittal and frontal acquisitions. Several structures were preserved in the procedure: facial reliefs, inferior orbital rim and orbital floor, posterior wall of the maxillary sinus covering the pterygopalatine fossa, lateral and medial pterygoid plates and pterygopalatine ganglion with its branches, lateral facial neurovascular pedicle, teeth and soft palate. Other structures were sacrificed: arteries and nerves located at the sites of skin and mucosal incision, and at the sites of osteotomies, ie the infraorbital nerve, the distal part of the greater palatine nerve, the nerves supplying the naso-pharynx, the nasal septum and the nasal conchae, nasolacrimal groove and lacrimal canal. The NMCF technique gives wide access to the deep nasal and nasopharyngeal areas. It is essential to preserve the lateral facial neurovascular pedicle to prevent necrosis of the midface structures. Preservation of the bony architecture surrounding the osteotomy sites is of great importance to allow precise final bone reassembly. Preoperative MRI appears of paramount importance to determine the borders of the lesion and the possibility of block resection. PMID:9894318

Prudhomme, M; Landgrebe, J; Maubon, M; Curioni, C; Clauser, L; Godlewski, G

1998-01-01

158

Locally Linear Diffeomorphic Metric Embedding (LLDME) for surface-based anatomical shape modeling.  

Science.gov (United States)

This paper presents the algorithm, Locally Linear Diffeomorphic Metric Embedding (LLDME), for constructing efficient and compact representations of surface-based brain shapes whose variations are characterized using Large Deformation Diffeomorphic Metric Mapping (LDDMM). Our hypothesis is that the shape variations in the infinite-dimensional diffeomorphic metric space can be captured by a low-dimensional space. To do so, traditional Locally Linear Embedding (LLE) that reconstructs a data point from its neighbors in Euclidean space is extended to LLDME that requires interpolating a shape from its neighbors in the infinite-dimensional diffeomorphic metric space. This is made possible through the conservation law of momentum derived from LDDMM. It indicates that initial momentum, a linear transformation of the initial velocity of diffeomorphic flows, at a fixed template shape determines the geodesic connecting the template to a subject's shape in the diffeomorphic metric space and becomes the shape signature of an individual subject. This leads to the compact linear representation of the nonlinear diffeomorphisms in terms of the initial momentum. Since the initial momentum is in a linear space, a shape can be approximated by a linear combination of its neighbors in the diffeomorphic metric space. In addition, we provide efficient computations for the metric distance between two shapes through the first order approximation of the geodesic using the initial momentum as well as for the reconstruction of a shape given its low-dimensional Euclidean coordinates using the geodesic shooting with the initial momentum as the initial condition. Experiments are performed on the hippocampal shapes of 302 normal subjects across the whole life span (18-94years). Compared with Principal Component Analysis and ISOMAP, LLDME provides the most compact and efficient representation of the age-related hippocampal shapes. Even though the hippocampal volumes among young adults are as variable as those in older adults, LLDME disentangles the hippocampal local shape variation from the hippocampal size and thus reveals the nonlinear relationship of the hippocampal morphometry with age. PMID:21281721

Yang, Xianfeng; Goh, Alvina; Qiu, Anqi

2011-05-01

159

Navigation with two landmarks in rats (Rattus norvegicus): The role of landmark salience.  

Science.gov (United States)

In two experiments, male and female rats were trained in a Morris pool in the presence of 1 (Experiment 1) or 2 (Experiment 2) landmarks, which were placed relatively close in relation to a hidden platform. Experiment 1 established the relative salience of 3 landmarks. Two of them revealed a similar salience, and smaller than a third one, the most salient landmark, both in training and on a test trial without the platform. Then in Experiment 2 rats were extensively trained to find a hidden platform in the presence of a configuration formed by 2 landmarks and the effects of varying the salience of one of the landmarks were studied. Subsequent test trials without the platform revealed that finding the platform was controlled by different strategies and that the rats were taking advantage of this redundancy depending on the nature of the test trials. Surprisingly, in Experiment 2 a clear sex difference was found on escape trials only, with males reaching the platform faster than females. (PsycINFO Database Record (c) 2014 APA, all rights reserved). PMID:24749502

Rodrigo, Teresa; Gimeno, Elisabet; Ayguasanosa, Meritxell; Chamizo, Victoria D

2014-11-01

160

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

International Nuclear Information System (INIS)

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.

 
 
 
 
161

Motion representation of the long fingers: a proposal for the definitions of new anatomical frames.  

Science.gov (United States)

Despite the availability of the International Society of Biomechanics (ISB) recommendations for the orientation of anatomical frames, no consensus exists about motion representations related to finger kinematics. This paper proposes novel anatomical frames for motion representation of the phalangeal segments of the long fingers. A three-dimensional model of a human forefinger was acquired from a non-pathological fresh-frozen hand. Medical imaging was used to collect phalangeal discrete positions. Data processing was performed using a customized software interface ("lhpFusionBox") to create a specimen-specific model and to reconstruct the discrete motion path. Five examiners virtually palpated two sets of landmarks. These markers were then used to build anatomical frames following two methods: a reference method following ISB recommendations and a newly-developed method based on the mean helical axis (HA). Motion representations were obtained and compared between examiners. Virtual palpation precision was around 1mm, which is comparable to results from the literature. The comparison of the two methods showed that the helical axis method seemed more reproducible between examiners especially for secondary, or accessory, motions. Computed Root Mean Square distances comparing methods showed that the ISB method displayed a variability 10 times higher than the HA method. The HA method seems to be suitable for finger motion representation using discrete positions from medical imaging. Further investigations are required before being able to use the methodology with continuous tracking of markers set on the subject's hand. PMID:24612716

Coupier, Jérôme; Moiseev, Fédor; Feipel, Véronique; Rooze, Marcel; Van Sint Jan, Serge

2014-04-11

162

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

163

The importance of accurate anatomic assessment for the volumetric analysis of the amygdala  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english There is a wide range of values reported in volumetric studies of the amygdala. The use of single plane thick magnetic resonance imaging (MRI) may prevent the correct visualization of anatomic landmarks and yield imprecise results. To assess whether there is a difference between volumetric analysis [...] of the amygdala performed with single plane MRI 3-mm slices and with multiplanar analysis of MRI 1-mm slices, we studied healthy subjects and patients with temporal lobe epilepsy. We performed manual delineation of the amygdala on T1-weighted inversion recovery, 3-mm coronal slices and manual delineation of the amygdala on three-dimensional volumetric T1-weighted images with 1-mm slice thickness. The data were compared using a dependent t-test. There was a significant difference between the volumes obtained by the coronal plane-based measurements and the volumes obtained by three-dimensional analysis (P

L., Bonilha; E., Kobayashi; F., Cendes; L.M., Li.

164

The importance of accurate anatomic assessment for the volumetric analysis of the amygdala  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english There is a wide range of values reported in volumetric studies of the amygdala. The use of single plane thick magnetic resonance imaging (MRI) may prevent the correct visualization of anatomic landmarks and yield imprecise results. To assess whether there is a difference between volumetric analysis [...] of the amygdala performed with single plane MRI 3-mm slices and with multiplanar analysis of MRI 1-mm slices, we studied healthy subjects and patients with temporal lobe epilepsy. We performed manual delineation of the amygdala on T1-weighted inversion recovery, 3-mm coronal slices and manual delineation of the amygdala on three-dimensional volumetric T1-weighted images with 1-mm slice thickness. The data were compared using a dependent t-test. There was a significant difference between the volumes obtained by the coronal plane-based measurements and the volumes obtained by three-dimensional analysis (P

L., Bonilha; E., Kobayashi; F., Cendes; L.M., Li.

2005-03-01

165

[Mediaeval anatomic iconography (Part II)].  

Science.gov (United States)

In the second part of his paper the author has presented a mediaeval anatomical draft based on empirical studies. From the first drawings from XVth century showing the places of blood-letting and connected with astrological prognostics, to systematical drawings by Guido de Vigevano. He has stressed the parallel existence of two lines of teaching anatomy; one based on philosophical concepts (discussed in the first part of paper), the second one based on empirical concepts. The latter trend has formed the grounds for final transformation, which has taken place in anatomical science in age of Renaissance. PMID:11625191

Barg, L

1996-01-01

166

Concurrent map building and localization with landmark validation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This communication addresses the issue of concurrent map building and localization (CML) for a mobile robot in an unknown environment. The proposed solution extends over previous contributions in that the environment must not be static, nor the landmarks be uniquely identifiable. To this aim we introduce a map model that includes not only the robot and landmark locations in a reference frame, but also a model for landmark quality assessment. Convergence of the map covariance is preserved in t...

Andrade Cetto, Juan; Sanfeliu Corte?s, Alberto

2002-01-01

167

Detection of natural landmarks through multiscale opponent features  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Todt, Eduardo; Torras Geni?s, Carme

2000-01-01

168

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

169

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; Larsen, Rasmus

2007-01-01

170

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 SciELO Brazil | Language: English Abstract in portuguese 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.

171

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 SciELO Brazil | Language: English Abstract in portuguese 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

172

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

173

Coronary arterial dynamics computation with medical-image-based time-dependent anatomical models and element-based zero-stress state estimates  

Science.gov (United States)

We propose a method for coronary arterial dynamics computation with medical-image-based time-dependent anatomical models. The objective is to improve the computational analysis of coronary arteries for better understanding of the links between the atherosclerosis development and mechanical stimuli such as endothelial wall shear stress and structural stress in the arterial wall. The method has two components. The first one is element-based zero-stress (ZS) state estimation, which is an alternative to prestress calculation. The second one is a "mixed ZS state" approach, where the ZS states for different elements in the structural mechanics mesh are estimated with reference configurations based on medical images coming from different instants within the cardiac cycle. We demonstrate the robustness of the method in a patient-specific coronary arterial dynamics computation where the motion of a thin strip along the arterial surface and two cut surfaces at the arterial ends is specified to match the motion extracted from the medical images.

Takizawa, Kenji; Torii, Ryo; Takagi, Hirokazu; Tezduyar, Tayfun E.; Xu, Xiao Y.

2014-10-01

174

Midline Incisional Hernia. Anatomical Repairs for the Treatment with Prothesis  

Directory of Open Access Journals (Sweden)

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

Madeo, Sergio Damián

2012-09-01

175

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

Science.gov (United States)

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.

Mertes, Marcel; Dittmar, Laura; Egelhaaf, Martin; Boeddeker, Norbert

2014-01-01

176

Elections and landmark policies in Tanzania and Uganda  

DEFF Research Database (Denmark)

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

Kjær, Anne Mette; Therkildsen, Ole

2013-01-01

177

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

Science.gov (United States)

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

Takano, Yukinori; Hirata, Akimasa; Fujiwara, Osamu

178

The importance of accurate anatomic assessment for the volumetric analysis of the amygdala  

Directory of Open Access Journals (Sweden)

Full Text Available There is a wide range of values reported in volumetric studies of the amygdala. The use of single plane thick magnetic resonance imaging (MRI may prevent the correct visualization of anatomic landmarks and yield imprecise results. To assess whether there is a difference between volumetric analysis of the amygdala performed with single plane MRI 3-mm slices and with multiplanar analysis of MRI 1-mm slices, we studied healthy subjects and patients with temporal lobe epilepsy. We performed manual delineation of the amygdala on T1-weighted inversion recovery, 3-mm coronal slices and manual delineation of the amygdala on three-dimensional volumetric T1-weighted images with 1-mm slice thickness. The data were compared using a dependent t-test. There was a significant difference between the volumes obtained by the coronal plane-based measurements and the volumes obtained by three-dimensional analysis (P < 0.001. An incorrect estimate of the amygdala volume may preclude a correct analysis of the biological effects of alterations in amygdala volume. Three-dimensional analysis is preferred because it is based on more extensive anatomical assessment and the results are similar to those obtained in post-mortem studies.

L. Bonilha

2005-03-01

179

Post-trial anatomical frame alignment procedure for comparison of 3D joint angle measurement from magnetic/inertial measurement units and camera-based systems.  

Science.gov (United States)

Magnetic and inertial measurement units (MIMUs) have been widely used as an alternative to traditional camera-based motion capture systems for 3D joint kinematics measurement. Since these sensors do not directly measure position, a pre-trial anatomical calibration, either with the assistance of a special protocol/apparatus or with another motion capture system is required to establish the transformation matrices between the local sensor frame and the anatomical frame (AF) of each body segment on which the sensors are attached. Because the axes of AFs are often used as the rotational axes in the joint angle calculation, any difference in the AF determination will cause discrepancies in the calculated joint angles. Therefore, a direct comparison of joint angles between MIMU systems and camera-based systems is less meaningful because the calculated joint angles contain a systemic error due to the differences in the AF determination. To solve this problem a new post-trial AF alignment procedure is proposed. By correcting the AF misalignments, the joint angle differences caused by the difference in AF determination are eliminated and the remaining discrepancies are mainly from the measurement accuracy of the systems themselves. Lower limb joint angles from 30 walking trials were used to validate the effectiveness of the proposed AF alignment procedure. This technique could serve as a new means for calibrating magnetic/inertial sensor-based motion capture systems and correcting for AF misalignment in scenarios where joint angles are compared directly. PMID:25340557

Li, Qingguo; Zhang, Jun-Tian

2014-12-01

180

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

Science.gov (United States)

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

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

2014-01-01

 
 
 
 
181

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

182

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

183

Anatomic Total Shoulder System  

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Full Text Available ... able to watch a live global AP anatomic total shoulder surgery from Methodist Hospital in Philadelphia. A revolution in ... Thank you for watching this Global AP Anatomic Total Shoulder surgery, which featured the latest innovation in shoulder surgery ...

184

Anatomic Total Shoulder System  

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

185

Including Anatomical and Functional Information in MC Simulation of PET and SPECT Brain Studies. Brain-VISET: A Voxel-Based Iterative Method.  

Science.gov (United States)

Monte Carlo (MC) simulation provides a flexible and robust framework to efficiently evaluate and optimize image processing methods in emission tomography. In this work we present Brain-VISET (Voxel-based Iterative Simulation for Emission Tomography), a method that aims to simulate realistic [ (99m) Tc]-SPECT and [ (18) F]-PET brain databases by including anatomical and functional information. To this end, activity and attenuation maps generated using high-resolution anatomical images from patients were used as input maps in a MC projector to simulate SPECT or PET sinograms. The reconstructed images were compared with the corresponding real SPECT or PET studies in an iterative process where the activity inputs maps were being modified at each iteration. Datasets of 30 refractory epileptic patients were used to assess the new method. Each set consisted of structural images (MRI and CT) and functional studies (SPECT and PET), thereby allowing the inclusion of anatomical and functional variability in the simulation input models. SPECT and PET sinograms were obtained using the SimSET package and were reconstructed with the same protocols as those employed for the clinical studies. The convergence of Brain-VISET was evaluated by studying the behavior throughout iterations of the correlation coefficient, the quotient image histogram and a ROI analysis comparing simulated with real studies. The realism of generated maps was also evaluated. Our findings show that Brain-VISET is able to generate realistic SPECT and PET studies and that four iterations is a suitable number of iterations to guarantee a good agreement between simulated and real studies. PMID:24876110

Marti-Fuster, Berta; Esteban, Oscar; Thielemans, Kris; Setoain, Xavier; Santos, Andres; Ros, Domenec; Pavia, Javier

2014-10-01

186

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

187

NOTE: The Virtual Family—development of surface-based anatomical models of two adults and two children for dosimetric simulations  

Science.gov (United States)

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

Christ, Andreas; Kainz, Wolfgang; Hahn, Eckhart G.; Honegger, Katharina; Zefferer, Marcel; Neufeld, Esra; Rascher, Wolfgang; Janka, Rolf; Bautz, Werner; Chen, Ji; Kiefer, Berthold; Schmitt, Peter; Hollenbach, Hans-Peter; Shen, Jianxiang; Oberle, Michael; Szczerba, Dominik; Kam, Anthony; Guag, Joshua W.; Kuster, Niels

2010-01-01

188

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

189

Landmarks and ant search strategies after interrupted tandem runs.  

Science.gov (United States)

During a tandem run, a single leading ant recruits a single follower to an important resource such as a new nest. To examine this process, we used a motorized gantry, which has not previously been used in ant studies, to track tandem running ants accurately in a large arena and we compared their performance in the presence of different types of landmark. We interrupted tandem runs by taking away the leader and moved a large distant landmark behind the new nest just at the time of this separation. Our aim was to determine what information followers might have obtained from the incomplete tandem run they had followed, and how they behaved after the tandem run had been interrupted. Our results show that former followers search by using composite random strategies with elements of sub-diffusive and diffusive movements. Furthermore, when we provided more landmarks former followers searched for longer. However, when all landmarks were removed completely from the arena, the ants' search duration lasted up to four times longer. Hence, their search strategy changes in the presence or absence of landmarks. Even after extensive search of this kind, former followers headed back to their old nest but did not return along the path of the tandem run they had followed. The combination of the position to which the large distant landmark behind the new nest was moved and the presence or absence of additional landmarks influenced the orientation of the former followers' paths back to the old nest. We also found that these ants exhibit behavioural lateralization in which they possibly use their right eye more than their left eye to recognize landmarks for navigation. Our results suggest that former follower ants learn landmarks during tandem running and use this information to make strategic decisions. PMID:24198259

Basari, Norasmah; Bruendl, Aisha C; Hemingway, Charlotte E; Roberts, Nicholas W; Sendova-Franks, Ana B; Franks, Nigel R

2014-03-15

190

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

International Nuclear Information System (INIS)

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

191

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

192

3D face analysis : landmarking, expression recognition and beyond  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

193

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

194

Anatomic Total Shoulder System  

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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. ...

195

Anatomic Total Shoulder System  

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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 ...

196

Anatomic Total Shoulder System  

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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 ...

197

Anatomic Total Shoulder System  

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Full Text Available ... so that it comes out of the osteotomy surface at the anatomic neck. Hit me. 00:05: ... and then advance it over to the osteotomy surface, but pretty much anything else, I think anything ...

198

Anatomic Total Shoulder System  

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

199

A Multi-Atlas Based Method for Automated Anatomical Rat Brain MRI Segmentation and Extraction of PET Activity  

Science.gov (United States)

Introduction Preclinical in vivo imaging requires precise and reproducible delineation of brain structures. Manual segmentation is time consuming and operator dependent. Automated segmentation as usually performed via single atlas registration fails to account for anatomo-physiological variability. We present, evaluate, and make available a multi-atlas approach for automatically segmenting rat brain MRI and extracting PET activies. Methods High-resolution 7T 2DT2 MR images of 12 Sprague-Dawley rat brains were manually segmented into 27-VOI label volumes using detailed protocols. Automated methods were developed with 7/12 atlas datasets, i.e. the MRIs and their associated label volumes. MRIs were registered to a common space, where an MRI template and a maximum probability atlas were created. Three automated methods were tested: 1/registering individual MRIs to the template, and using a single atlas (SA), 2/using the maximum probability atlas (MP), and 3/registering the MRIs from the multi-atlas dataset to an individual MRI, propagating the label volumes and fusing them in individual MRI space (propagation & fusion, PF). Evaluation was performed on the five remaining rats which additionally underwent [18F]FDG PET. Automated and manual segmentations were compared for morphometric performance (assessed by comparing volume bias and Dice overlap index) and functional performance (evaluated by comparing extracted PET measures). Results Only the SA method showed volume bias. Dice indices were significantly different between methods (PF>MP>SA). PET regional measures were more accurate with multi-atlas methods than with SA method. Conclusions Multi-atlas methods outperform SA for automated anatomical brain segmentation and PET measure’s extraction. They perform comparably to manual segmentation for FDG-PET quantification. Multi-atlas methods are suitable for rapid reproducible VOI analyses. PMID:25330005

Lancelot, Sophie; Roche, Roxane; Slimen, Afifa; Bouillot, Caroline; Levigoureux, Elise; Langlois, Jean-Baptiste; Zimmer, Luc; Costes, Nicolas

2014-01-01

200

Anatomical imaging for radiotherapy  

International Nuclear Information System (INIS)

ue as well as radiation attenuation estimation for dose prediction. Magnetic resonance imaging is fast becoming widespread alongside CT, enabling superior soft-tissue visualization. Traditionally scanning for treatment planning has relied on the use of a single snapshot scan. Recent years have seen the development of techniques such as 4D CT and adaptive radiotherapy (ART). In 4D CT raw data are encoded with phase information and reconstructed to yield a set of scans detailing motion through the breathing, or cardiac, cycle. In ART a set of scans is taken on different days. Both allow planning to account for variability intrinsic to the patient. Treatment verification has been carried out using a variety of technologies including: MV portal imaging, kV portal/fluoroscopy, MVCT, conebeam kVCT, ultrasound and optical surface imaging. The various methods have their pros and cons. The four x-ray methods involve an extra radiation dose to normal tissue. The portal methods may not generally be used to visualize soft tissue, consequently they are often used in conjunction with implanted fiducial markers. The two CT-based methods allow measurement of inter-fraction variation only. Ultrasound allows soft-tissue measurement with zero dose but requires skilled interpretation, and there is evidence of systematic differences between ultrasound and other data sources, perhaps due to the effects of the probe pressure. Optical imaging also involves zero dose but requires good correlation between the target and the external measurement and thus is often used in conjunction with an x-ray method. The use of anatomical imaging in radiotherapy allows treatment uncertainties to be determined. These include errors between the mean position at treatment and that at planning (the systematic error) and the day-to-day variation in treatment set-up (the random error). Positional variations may also be categorized in terms of inter- and intra-fraction errors. Various empirical treatment margin formulae and intervention approaches exist to determine the optimum strategies for treatment in the presence of these known errors. Other methods exist to try to minimize error margins drastically including the currently available breath-hold techniques and the tracking methods which are largely in development. This paper will review anatomical imaging techniques in radiotherapy and how they are used to boost the therapeutic benefit of the treatment. (topical review)

 
 
 
 
201

Geometry and landmark representation by pigeons: evidence for species-differences in the hemispheric organization of spatial information processing?  

Science.gov (United States)

In this study, we investigated how pigeons (Columba livia) represent environmental geometry and landmark information. Birds learned to locate the centre of a square arena by means of geometric cues alone, or by means of both geometric and landmark cues. By manipulating the type of information available at training and testing, we assessed which cues the birds had encoded, and through the use of monocular occlusion we examined how the information was represented by the two brain hemispheres. Our results show that both brain hemispheres encoded geometric and landmark information. During all viewing conditions, the geometric representation was based mainly on an absolute metric for distance. The relative use of geometry and landmarks was experience dependent. With both brain hemispheres available birds relied, to a greater degree, on geometric information and used it in a more integrated way than with either hemisphere alone. Overall, our findings show a different pattern for the hemispheric encoding of geometric and landmark information by the pigeon than that previously reported for the domestic chick. Our results suggest that the organization of spatial information processing in the left and right brain hemispheres of birds may be more diverse than what is currently known. PMID:19200073

Wilzeck, Christiane; Prior, Helmut; Kelly, Debbie M

2009-02-01

202

Modeling and matching of landmarks for automation of Mars Rover localization  

Science.gov (United States)

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

Wang, Jue

203

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

International Nuclear Information System (INIS)

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

204

Proper name retrieval in temporal lobe epilepsy: naming of famous faces and landmarks.  

Science.gov (United States)

The objective of this study was to further explore proper name (PN) retrieval and conceptual knowledge in patients with left and right temporal lobe epilepsy (69 patients with LTLE and 62 patients with RTLE) using a refined assessment procedure. Based on the performance of a large group of age- and education-matched normals, a new test of famous faces and famous landmarks was designed. Recognition, naming, and semantic knowledge were assessed consecutively, allowing for a better characterization of deficient levels in the naming system. Impairment in PN retrieval was common in the cohort with TLE. Furthermore, side of seizure onset impaired stages of name retrieval differently: LTLE impaired the lexico-phonological processing, whereas RTLE mainly impaired the perceptual-semantic stage of object recognition. In addition to deficient PN retrieval, patients with TLE had reduced conceptual knowledge regarding famous persons and landmarks. PMID:23542541

Benke, Thomas; Kuen, Eva; Schwarz, Michael; Walser, Gerald

2013-05-01

205

Anatomical considerations of the neonatal ilio-inguinal/ iliohypogastric nerve block  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The ilioinguinal/ iliohypogastric nerve block is an effective technique that provides analgesia for a variety of inguinal surgical procedures in children. However, a relatively high failure rate of between 20-30% has been reported. The aim of this study was to determine the exact anatomical position of the ilio-inguinal and iliohypogastric nerves in relation to an easily identifiable bony landmark, the anterior superior iliac spine (ASIS), in neonates. Dissections were performed on a sample o...

Schoor, A.; Bosman, M. C.; Bosenberg, A. T.

2009-01-01

206

Honey bees store landmarks in an egocentric frame of reference.  

Science.gov (United States)

Honey bees are well known to rely on stored landmark information to locate a previously visited site. While various mechanisms underlying insect navigation have been thoroughly explored, little is yet known about the degree of integration of spatial parameters to form higher-level spatial representations. In this paper we explore the basic interactions between landmark cues and directional cues, which stand at the basis of our understanding of piloting mechanisms. A novel experimental paradigm allowed us independent manipulation of each parameter in a highly controlled environment. The approach taken was twofold: cue-conflict experiments were first conducted to examine the interactions between positional cues and directional cues. The bees were then successively deprived of sensory cues to question the dependence of landmark navigation on context cues. Our results confirm previous findings that landmark cues are used in concert with external directional cues if present. Conversely, the bees' ability to locate a food site was not disrupted in the absence of an external directional reference. Thus, bees store landmark memories in an egocentric frame of reference and only loose and facultative associations between visual memories and compass cues are formed. PMID:11913810

Fry, Steven N; Wehner, Rüdiger

2002-01-01

207

Interactions of visual odometry and landmark guidance during food search in honeybees.  

Science.gov (United States)

How do honeybees use visual odometry and goal-defining landmarks to guide food search? In one experiment, bees were trained to forage in an optic-flow-rich tunnel with a landmark positioned directly above the feeder. Subsequent food-search tests indicated that bees searched much more accurately when both odometric and landmark cues were available than when only odometry was available. When the two cue sources were set in conflict, by shifting the position of the landmark in the tunnel during test, bees overwhelmingly used landmark cues rather than odometry. In another experiment, odometric cues were removed by training and testing in axially striped tunnels. The data show that bees did not weight landmarks as highly as when odometric cues were available, tending to search in the vicinity of the landmark for shorter periods. A third experiment, in which bees were trained with odometry but without a landmark, showed that a novel landmark placed anywhere in the tunnel during testing prevented bees from searching beyond the landmark location. Two further experiments, involving training bees to relatively longer distances with a goal-defining landmark, produced similar results to the initial experiment. One caveat was that, with the removal of the familiar landmark, bees tended to overshoot the training location, relative to the case where bees were trained without a landmark. Taken together, the results suggest that bees assign appropriate significance to odometric and landmark cues in a more flexible and dynamic way than previously envisaged. PMID:16244171

Vladusich, Tony; Hemmi, Jan M; Srinivasan, Mandyam V; Zeil, Jochen

2005-11-01

208

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-07-15

209

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

International Nuclear Information System (INIS)

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

210

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

211

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

Science.gov (United States)

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

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

2014-12-01

212

Precise visual navigation using multi-stereo vision and landmark matching  

Science.gov (United States)

Traditional vision-based navigation system often drifts over time during navigation. In this paper, we propose a set of techniques which greatly reduce the long term drift and also improve its robustness to many failure conditions. In our approach, two pairs of stereo cameras are integrated to form a forward/backward multi-stereo camera system. As a result, the Field-Of-View of the system is extended significantly to capture more natural landmarks from the scene. This helps to increase the pose estimation accuracy as well as reduce the failure situations. Secondly, a global landmark matching technique is used to recognize the previously visited locations during navigation. Using the matched landmarks, a pose correction technique is used to eliminate the accumulated navigation drift. Finally, in order to further improve the robustness of the system, measurements from low-cost Inertial Measurement Unit (IMU) and Global Positioning System (GPS) sensors are integrated with the visual odometry in an extended Kalman Filtering framework. Our system is significantly more accurate and robust than previously published techniques (1~5% localization error) over long-distance navigation both indoors and outdoors. Real world experiments on a human worn system show that the location can be estimated within 1 meter over 500 meters (around 0.1% localization error averagely) without the use of GPS information.

Zhu, Zhiwei; Oskiper, Taragay; Samarasekera, Supun; Kumar, Rakesh

2007-04-01

213

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

214

Anatomic Total Shoulder System  

Medline Plus

Full Text Available ... What makes one patient a candidate for an anatomic versus a reverse arthroplasty? 00:51:31 GERALD WILLIAMS, MD: Lack of a rotator cuff. If somebody has an intact rotator cuff with a center joint, they don't ever get a reverse. At least not in the United States. They might in Europe, but they don't ...

215

Anatomic Total Shoulder System  

Medline Plus

Full Text Available ... III, MD: Exactly. Choices -- selection of primary versus reverse shoulder arthroplasty. 00:51:24 GERALD WILLIAMS, MD: Say that again. 00:51:26 N. DOUGLAS BOARDMAN III, MD: What makes one patient a candidate for an anatomic versus a reverse arthroplasty? 00:51:31 GERALD WILLIAMS, MD: Lack ...

216

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 ...

217

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 SciELO Chile | Language: Spanish Abstract in spanish 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

218

Anatomy of the Clitoris: Revision and Clarifications about the Anatomical Terms for the Clitoris Proposed (without Scientific Bases) by Helen O'Connell, Emmanuele Jannini, and Odile Buisson  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The anatomy of the clitoris is described in human anatomy textbooks. Some researchers have proposal and divulged a new anatomical terminology for the clitoris. This paper is a revision of the anatomical terms proposed by Helen O'Connell, Emmanuele Jannini, and Odile Buisson. Gynecologists, sexual medicine experts, and sexologists should spread certainties for all women, not hypotheses or personal opinions, they should use scientific terminology: clitoral/vaginal/uterine orgasm, G/A/C/U spot o...

Vincenzo Puppo

2011-01-01

219

[Establishment of anatomical terminology in Japan].  

Science.gov (United States)

The history of anatomical terminology in Japan began with the publication of Waran Naikei Ihan-teim? in 1805 and Ch?tei Kaitai Shinsho in 1826. Although the establishment of Japanese anatomical terminology became necessary during the Meiji era when many western anatomy books imported into Janan were translated, such terminology was not unified during this period and varied among translators. In 1871, Tsukumo Ono's Kaib?gaku Gosen was published by the Ministry of Education. Although this book is considered to be the first anatomical glossary terms in Japan, its contents were incomplete. Overseas, the German Anatomical Society established a unified anatomical terminology in 1895 called the Basle Nomina Anatomica (B.N.A.). Based on this development, Kaib?gaku Meish? which follows the BNA, by Buntar? Suzuki was published in 1905. With the subsequent establishment in 1935 of Jena Nomina Anatomica (J.N.A.), the unification of anatomical terminology was also accelerated in Japan, leading to the further development of terminology. PMID:19108488

Shimada, Kazuyuki

2008-12-01

220

A field study investigating effects of landmarks on territory size and shape.  

Science.gov (United States)

Few studies have examined how landmarks affect territories' fundamental characteristics. In this field study, we investigated effects of landmarks on territory size, shape and location in a cichlid fish (Amatitlania siquia). We provided cans as breeding sites and used plastic plants as landmarks. During 10 min trials, we recorded locations where residents chased intruders and used those locations to outline and measure the territory. In two experiments, we observed pairs without landmarks and with either a point landmark (one plant) or linear landmark (four plants) placed near the nest can. We alternated which trial occurred first and performed the second trial 24 h after the first. Territories were approximately round without landmarks or with a point landmark but were significantly more elongated when we added a linear landmark. Without landmarks, nests were centrally located; however, with any landmark, pairs set territory boundaries closer to the landmark and thus the nest. Territory size was significantly reduced in the presence of any landmark. This reduction suggests that a smaller territory with well-defined boundaries has greater benefits than a larger territory with less well-defined borders. PMID:24759367

Suriyampola, Piyumika S; Eason, Perri K

2014-01-01

 
 
 
 
221

Assessment of organ doses from exposure to neutrons using the Monte Carlo technique and an image-based anatomical model  

Science.gov (United States)

The distribution of absorbed doses in the body can be computationally determined using mathematical or tomographic representations of human anatomy. A whole- body model was developed from the color images of the National Library of Medicine's Visible Human Project® for simulating the transport of radiation in the human body. The model, called Visible Photographic Man (VIP-Man), has sixty-one organs and tissues represented in the Monte Carlo code MCNPX at 4-mm voxel resolution. Organ dose calculations from external neutron sources were carried out using VIP-man and MCNPX to determine a new set of dose conversion coefficients to be used in radiation protection. Monoenergetic neutron beams between 10-9 MeV and 10 GeV were studied under six different irradiation geometries: anterior-posterior, posterior-anterior, right lateral, left lateral, rotational and isotropic. The results for absorbed doses in twenty-four organs and the effective doses based on twelve critical organs are presented in tabular form. A comprehensive comparison of the results with those from the mathematical models show discrepancies that can be attributed to the variations in body modeling (size, location and shape of the individual organs) and the use of different nuclear datasets or models to derive the reaction cross sections, as well as the use of different transport packages for simulation radiation effects. The organ dose results based on the realistic VIP-Man body model allow the existing radiation protection dosimetry on neutrons to be re-evaluated and improved.

Bozkurt, Ahmet

222

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

223

Anatomical consideration of Dhamani marma in Ayurveda  

Directory of Open Access Journals (Sweden)

Full Text Available 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 structures. Marma in Ayurvedic classics is illustrated as the vital point in human body, the injury of which leads to termination of life. Descriptions of 107 marmas given by all acharyas being classified into five varieties on the basis of structure involved; five on the basis of effect of injury and five on the basis of location on the body. According to anatomical consideration marmas can be divided into mansa-marma, sira-marma, snayu-marma, sandhi-marma, and asthi-marma (respectively, marma of muscle, blood vessel, ligament, joint and bone. According to Vagabhatta there are six types of marma. He has enumerated a sixth group of marma known as dhamani marma. Dhamani marma is one such vital region in human anatomy which falls under the classification on the basis of structure involved. This study is aimed to emphasize on why Ashtanga Hridaya has considered a separate group called dhamani marmas of which other acharyas have considered under different groups & finally to conclude with clearing out the controversy & thereby to fulfill the lacuna in the subject.

Bhan Pratap Yadaw

2014-09-01

224

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

225

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

226

Cuttlefish rely on both polarized light and landmarks for orientation.  

Science.gov (United States)

Cuttlefish are sensitive to linear polarization of light, a sensitivity that they use in predation and possibly in intraspecific communication. It has also been shown that cuttlefish are able to solve a maze using visual landmarks. In this study, cuttlefish were trained to solve a Y-maze with the e-vector of a polarized light and landmarks as redundant spatial information. The results showed that cuttlefish can use the e-vector orientation and landmarks in parallel to orient and that they are able to use either type of cue when the other one is missing. When they faced conflicting spatial information in the experimental apparatus, the majority of cuttlefish followed the e-vector rather than landmarks. Differences in response latencies in the different conditions of testing (training with both types of cue, tests with single cue or with conflicting information) were observed and discussed in terms of decision making. The ability to use near field and far field information may enable animals to interpret the partially occluded underwater light field. PMID:22460628

Cartron, Lelia; Darmaillacq, Anne-Sophie; Jozet-Alves, Christelle; Shashar, Nadav; Dickel, Ludovic

2012-07-01

227

Identifying landmark articles for advancing the practice of geriatrics.  

Science.gov (United States)

Landmark articles from the peer-reviewed literature can be used to teach the fundamental principles of geriatric medicine. Three approaches were used in sequential combination to identify landmark articles as a resource for geriatricians and other healthcare practitioners. Candidate articles were identified first through a literature review and expert opinion survey of geriatric medicine faculty. Candidate articles in a winnowed list (n = 30) were then included in a bibliometric analysis that incorporated the journal impact factor and average monthly citation index. Finally, a consensus panel reviewed articles to assess each manuscript's clinical relevance. For each article, a final score was determined by averaging, with equal weight, the opinion survey, bibliometric analysis, and consensus panel review. This process ultimately resulted in the identification of 27 landmark articles. Overall, there was weak correlation between articles that the expert opinion survey and bibliometric analysis both rated highly. This process demonstrates a feasible method combining subjective and objective measures that can be used to identify landmark papers in geriatric medicine for the enhancement of geriatrics education and practice. PMID:25366821

Vaughan, Camille P; Fowler, Rachel; Goodman, Richard A; Graves, Taylor R; Flacker, Jonathan M; Johnson, Theodore M

2014-11-01

228

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

229

36 CFR 65.9 - Withdrawal of National Historic Landmark designation.  

Science.gov (United States)

(a) National Historic Landmarks will be considered for withdrawal of designation only at the request of the owner or upon the initiative of the Secretary. (b) Four justifications exist for the withdrawal of National Historic Landmark...

2010-07-01

230

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

231

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)

232

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

233

Solving small spaces: investigating the use of landmark cues in brown capuchins (Cebus apella).  

Science.gov (United States)

Some researchers have recently argued that humans may be unusual among primates in preferring to use landmark information when reasoning about some kinds of spatial problems. Some have explained this phenomenon by positing that our species' tendency to prefer landmarks stems from a human-unique trait: language. Here, we test this hypothesis-that preferring to use landmarks to solve such tasks is related to language ability-by exploring landmark use in a spatial task in one non-human primate, the brown capuchin monkey (Cebus apella). We presented our subjects with the rotational displacement task, in which subjects attempt to relocate a reward hidden within an array of hiding locations which are subsequently rotated to a new position. Over several experiments, we varied the availability and the salience of a landmark cue within the array. Specifically, we varied (1) visual access to the array during rotation, (2) the type of landmark, (3) the consistency of the landmark qualities, and (4) the amount of exposure to the landmark. Across Experiments 1 through 4, capuchins did not successfully use landmarks cues, suggesting that non-linguistic primates may not spontaneously use landmarks to solve some spatial problems, as in this case of a small-scale dynamic spatial task. Importantly, we also observed that capuchins demonstrated some capacity to learn to use landmarks in Experiment 4, suggesting that non-linguistic creatures may be able to use some landmarks cues in similar spatial tasks with extensive training. PMID:23430144

Hughes, Kelly D; Mullo, Enma; Santos, Laurie R

2013-09-01

234

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

Science.gov (United States)

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

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

1998-06-01

235

[Extra-anatomic bypass].  

Science.gov (United States)

The authors describe their experience on extra-anatomic bypass effected in five years at their Hospital. This note assesses indications relative to rebuilding operations of this kind (in particular distal revascularization in patients at high risk, or as secondary operations at prosthesis infections), the complications that can derive and finally the series in our Hospital in the years between 1986 and 1991. In our experience axillo-mono, bi-femoral and femoro-femoral bypass have been effected getting excellent results, so we believe that these operating techniques should also be extended to younger patients and to patients with arteriopathies to the late second stage of Leriche-Fontaine. PMID:7991199

Tobaldi, F; Parca, A; Martino, G; Carnali, M

1994-09-01

236

What is expected of the facial nerve in michel aplasia? Anatomic variation.  

Science.gov (United States)

We sought better understanding about the facial nerve anatomy in the rare inner ear Michel anomaly to help better define this aplasia and prevent potential complications in surgery on these patients. The data from computed tomography scans and magnetic resonance images of six Michel aplastic ears (three patients) were evaluated for a facial nerve course. Facial nerve course and anatomic landmarks were noted. Based on data obtained from this group of very rare patients, three different facial nerve anatomies were encountered. The first patient had normal-looking mastoid cells, normal middle ear ossicles, and a completely formed facial nerve canal through the middle ear. The second patient had pneumatized mastoid air cells despite an anomalous ossicular chain. This patient also had a facial nerve canal but not through the middle ear. In the third patient, although mastoid cells were present, neither ossicles nor a definite facial nerve canal could be detected. With guidance provided by the anatomy of the other parts of the ear, such as air cells and the ossicular chain, the danger zones posing a high probability of facial nerve injury can be predicted. Although all Michel aplasias may have aplastic petrous bone in common, there are some degrees of variation. PMID:21772803

Zarandy, Masoud Motasaddi; Kouhi, Ali; Kashany, Shervin Sharif; Rabiei, Sohrab; Hajimohamadi, Fatemeh; Rabbani-Anari, Mahtab

2010-11-01

237

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

Scientific Electronic Library Online (English)

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

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

2006-06-01

238

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

Scientific Electronic Library Online (English)

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

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

239

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

Directory of Open Access Journals (Sweden)

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

Soubhagya R. Nayak

2006-06-01

240

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.)

 
 
 
 
241

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

242

A veterinary digital anatomical database.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper describes the Veterinary Digital Anatomical Database Project. The purpose of the project is to investigate the construction and use of digitally stored anatomical models. We will be discussing the overall project goals and the results to date. Digital anatomical models are 3 dimensional, solid model representations of normal anatomy. The digital representations are electronically stored and can be manipulated and displayed on a computer graphics workstation. A digital database of a...

Snell, J. R.; Green, R.; Stott, G.; Baerle, S.

1991-01-01

243

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

244

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

245

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)

246

MR neurography with multiplanar reconstruction of 3D MRI datasets: an anatomical study and clinical applications  

Energy Technology Data Exchange (ETDEWEB)

Extracranial MR neurography has so far mainly been used with 2D datasets. We investigated the use of 3D datasets for peripheral neurography of the sciatic nerve. A total of 40 thighs (20 healthy volunteers) were examined with a coronally oriented magnetization-prepared rapid acquisition gradient echo sequence with isotropic voxels of 1 x 1 x 1 mm and a field of view of 500 mm. Anatomical landmarks were palpated and marked with MRI markers. After MR scanning, the sciatic nerve was identified by two readers independently in the resulting 3D dataset. In every volunteer, the sciatic nerve could be identified bilaterally over the whole length of the thigh, even in areas of close contact to isointense muscles. The landmark of the greater trochanter was falsely palpated by 2.2 cm, and the knee joint by 1 cm. The mean distance between the bifurcation of the sciatic nerve and the knee-joint gap was 6 cm ({+-}1.8 cm). The mean results of the two readers differed by 1-6%. With the described method of MR neurography, the sciatic nerve was depicted reliably and objectively in great anatomical detail over the whole length of the thigh. Important anatomical information can be obtained. The clinical applications of MR neurography for the brachial plexus and lumbosacral plexus/sciatic nerve are discussed. (orig.)

Freund, Wolfgang; Aschoff, Andrik J.; Stuber, Gregor; Schmitz, Bernd [University Hospitals Ulm, Clinic for Diagnostic and Interventional Radiology, Ulm (Germany); Brinkmann, Alexander; Wagner, Florian; Dinse, Alexander [University Hospitals Ulm, Department of Anesthesiology, Ulm (Germany)

2007-04-15

247

MR neurography with multiplanar reconstruction of 3D MRI datasets: an anatomical study and clinical applications  

International Nuclear Information System (INIS)

Extracranial MR neurography has so far mainly been used with 2D datasets. We investigated the use of 3D datasets for peripheral neurography of the sciatic nerve. A total of 40 thighs (20 healthy volunteers) were examined with a coronally oriented magnetization-prepared rapid acquisition gradient echo sequence with isotropic voxels of 1 x 1 x 1 mm and a field of view of 500 mm. Anatomical landmarks were palpated and marked with MRI markers. After MR scanning, the sciatic nerve was identified by two readers independently in the resulting 3D dataset. In every volunteer, the sciatic nerve could be identified bilaterally over the whole length of the thigh, even in areas of close contact to isointense muscles. The landmark of the greater trochanter was falsely palpated by 2.2 cm, and the knee joint by 1 cm. The mean distance between the bifurcation of the sciatic nerve and the knee-joint gap was 6 cm (±1.8 cm). The mean results of the two readers differed by 1-6%. With the described method of MR neurography, the sciatic nerve was depicted reliably and objectively in great anatomical detail over the whole length of the thigh. Important anatomical information can be obtained. The clinical applications of MR neurography for the brachial plexus and lumbosacral plexus/sciatic nerve are discussed. (orig.)

248

The complexity of anatomical systems  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background The conception of anatomical entities as a hierarchy of infinitely graduated forms and the increase in the number of observed anatomical sub-entities and structural variables has generated a growing complexity, thus highlighting new properties of organised biological matter. Results (1 Complexity is so pervasive in the anatomical world that it has come to be considered as a primary characteristic of anatomical systems. (2 Anatomical entities, when viewed at microscopic as well as macroscopic level of observation, show a different degree of complexity. (3 Complexity can reside in the structure of the anatomical system (having many diverse parts with varying interactions or an intricate architecture or in its behaviour. Often complexity in structure and behaviour go together. (4 Complex systems admit many descriptions (ways of looking at the system each of which is only partially true. Each way of looking at a complex system requires its own description, its own mode of analysis and its own breaking down of the system in different parts; (5 Almost all the anatomical entities display hierarchical forms: their component structures at different spatial scales or their process at different time scales are related to each other. Conclusion The need to find a new way of observing and measuring anatomical entities, and objectively quantifying their different structural changes, prompted us to investigate the non-Euclidean geometries and the theories of complexity, and to apply their concepts to human anatomy. This attempt has led us to reflect upon the complex significance of the shape of an observed anatomical entity. Its changes have been defined in relation to variations in its status: from a normal (i.e. natural to a pathological or altered state introducing the concepts of kinematics and dynamics of anatomical forms, speed of their changes, and that of scale of their observation.

Grizzi Fabio

2005-07-01

249

Comparison of three standard anatomical reference frames for the tibia-fibula complex.  

Science.gov (United States)

Definition of anatomical reference frames is necessary both for in vitro biomechanical testing, and for in vivo human movement analyses. Different reference frames have been proposed in the literature for the lower limb, and in particular for the tibia-fibula complex. The scope of this work was to compare the three most commonly referred proposals (proposed by [Ruff, C.B., Hayes, W.C., 1983. Cross-sectional geometry at Pecos Pueblo femora and tibiae -A biomechanical investigation: I. method and general patterns of variation. American Journal of Physical Anthropology 60, pp. 359-381.], by [Cappozzo, A., Catani, F., Della Croce, U., Leardini, A., 1995. Position and orientation in space of bones during movement: anatomical frame definition and determination. Clinical Biomechanics (Bristol, Avon) 10, pp. 171-178.], and by the Standardization and Terminology Committee of the International Society of Biomechanics, [Wu, G., Siegler, S., Allard, P., Kirtley, C., Leardini, A., Rosenbaum, D., Whittle, M., D'Lima, D.D., Cristofolini, L., Witte, H., Schmid, O., Stokes, I., 2002. ISB recommendation on definitions of joint coordinate system of various joints for reporting of human joint motion-part I: ankle, hip and spine. International Society of Biomechanics. Journal of Biomechanics 35, pp. 543-548.]). These three frames were identified on six cadaveric tibia-fibula specimens based on the relevant anatomical landmarks, using a high-precision digitizer. The intra-operator (ten repetitions) and inter-operator (three operators) repeatability were investigated in terms of reference frame orientation. The three frames had similar intra-operator repeatability. The reference frame proposed by Ruff et al. had a better inter-operator repeatability (this must be put in relation with the original context of interest, i.e. in vitro measurements on dissected bones). The reference frames proposed by Ruff et al. and by ISB had a similar alignment; the frame proposed by Cappozzo et al. was considerably externally rotated and flexed with respect to the other two. Thus, the reference frame proposed by Ruff et al. is preferable when the full bone surface is accessible (typically during in vitro tests). Conversely, no advantage in terms of repeatability seems to exist between the reference frames proposed by Cappozzo et al. and ISB. PMID:18995859

Conti, Giorgia; Cristofolini, Luca; Juszczyk, Mateusz; Leardini, Alberto; Viceconti, Marco

2008-12-01

250

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.

251

Based On Edge Extraction of ASM Automatic Landmark Placement  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

252

Based On Edge Extraction of ASM Automatic Landmark Placement  

Directory of Open Access Journals (Sweden)

Full Text Available 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 model. Aiming at the characteristics of ASM modeling, this paper adopts a multiscale wavelet transform modulus maximum method of edge extraction, using the maximum variance method to obtain a threshold, after the use of connectivity judgment for each scale edge fusion. The simulation results show that, this algorithm can effectively reduce the burden, improve the modeling accuracy.

Zhang Liguo

2012-11-01

253

Extracción de puntos característicos del rostro para medidas antropométricas Face landmarks extraction for anthropometric measures  

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Full Text Available En este documento se propone una técnica para la extracción de 22 puntos característicos del rostro, orientada a aplicaciones de antropometría. La técnica se fundamenta en la transformada wavelets-Gabor y el uso del algoritmo EBGM (del término en inglés: Elastic Bunch Graph Matching. Este último algoritmo fue modificado para que los puntos extraídos correspondan a puntos característicos del rostro, los cuales se utilizan comúnmente en medidas antropométricas faciales. Las modificaciones consisten en un conjunto de restricciones geométricas para ajustar inicialmente la ubicación de los centros de búsqueda, y posteriormente para la definición de la región de esta búsqueda. Los resultados mostraron que los puntos centrales del rostro presentan errores de ubicación inferiores al milímetro, lo cual es consistente con las medidas en antropometría facial directa.In this research, a technique for the extraction of a 22 face landmarks set oriented to anthropometry applications has been proposed. The technique is based on wavelets Gabor transformation and the Elastic Bunch Graph Matching (EBGM algorithm. The EBGM algorithm was modified so that the extracted points correspond to face landmarks which are commonly used in face anthropometric measures. Modifications were: some geometric restrictions to initially fit the centers location of the region search, and later for the definition of the region. Results show that the face central points present location errors smaller than a millimeter, which is consistent with the measures in direct face anthropometry.

Alejandro González

2010-07-01

254

Multiplanar transcranial ultrasound imaging: standards, landmarks and correlation with magnetic resonance imaging.  

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The purpose of this study was to define a standardized multiplanar approach for transcranial ultrasound (US) imaging of brain parenchyma based on matched data from 3-D US and 3-D magnetic resonance imaging (MRI). The potential and limitations of multiple insonation planes in transverse and coronal orientation were evaluated for the visualization of intracranial landmarks in 60 healthy individuals (18 to 83 years old, mean 41.4 years) with sufficient temporal bone windows. Landmarks regularly visualized even in moderate sonographic conditions with identification rates of >75% were mesencephalon, pons, third ventricle, lateral ventricles, falx, thalamus, basal ganglia, pineal gland and temporal lobe. Identification of medulla oblongata, fourth ventricle, cerebellar structures, hippocampus, insula, frontal, parietal and occipital lobes was more difficult (<75%). We hypothesize that multiplanar transcranial US images, with standardized specification of tilt angles and orientation, not only allow comparison with other neuroimaging modalities, but may also provide a more objective framework for US monitoring of cerebral disease than freehand scanning. PMID:15749552

Kern, Rolf; Perren, Fabienne; Kreisel, Stefan; Szabo, Kristina; Hennerici, Michael; Meairs, Stephen

2005-03-01

255

Defining esophageal landmarks, gastroesophageal reflux disease, and Barrett's esophagus.  

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The following paper on gastroesophageal reflux disease (GERD) and Barrett's esophagus (BE) includes commentaries on defining esophageal landmarks; new techniques for evaluating upper esophageal sphincter (UES) tone; differential diagnosis of GERD, BE, and hiatal hernia (HH); the use of high-resolution manometry for evaluation of reflux; the role of fundic relaxation in reflux; the use of 24-h esophageal pH-impedance testing in differentiating acid from nonacid reflux and its potential inclusion in future Rome criteria; classification of endoscopic findings in GERD; the search for the cell origin that generates BE; and the relationship between BE, Barrett's carcinoma, and obesity. PMID:24117649

DeVault, Kenneth; McMahon, Barry P; Celebi, Altay; Costamagna, Guido; Marchese, Michele; Clarke, John O; Hejazi, Reza A; McCallum, Richard W; Savarino, Vincenzo; Zentilin, Patrizia; Savarino, Edoardo; Thomson, Mike; Souza, Rhonda F; Donohoe, Claire L; O'Farrell, Naoimh J; Reynolds, John V

2013-10-01

256

Ultrasound Anatomical Visualization of the rabbit liver  

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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

257

The avascular plane of the Achilles tendon: A quantitative anatomic and angiographic approach and a base for a possible new treatment option after rupture  

International Nuclear Information System (INIS)

Introduction: Achilles tendon ruptures, especially ruptures caused by pathologic conditions and also by achillotendinitis are often attributed to the alleged hypovascularisation of the Achilles tendon. Anatomic studies often mention an avascular plane. The purpose of this study was to re-investigate the arterial supply of the Achilles tendon. Material and methods: Lower legs of 28 anatomic specimen were injected with a radiologic contrast agent and subsequently an arterial angiography was performed. Afterwards the legs were embalmed and later anatomically dissected. The origin of arteries entering the paratenon of the tendo calcanei branching off from either the anterior (TA) or the posterior tibial artery (TP) was determined. The distance between the points of commencement of these nutrient arteries and a specific reference point, i.e. the insertion of the Achilles tendon into the tuber calcanei, was measured digitally on the radiographs and again with a slide-gauge on the dissected specimens. Results: As revealed by angiographic analysis, the TA gave off 5 vessels (v) at a frequency and median distance to the tuber calcanei (in cm) of v1: 50%, 6.01 cm; v2: 39.3%, 7.88 cm; v3: 35.7%, 9.71 cm; v4: 17.9%, 12.7 cm; v5: 10.7%, 14.6 cm. The TP contributed to the arterial supply of the Achilles tendon by means of 7 inserting arteries branching off at a frequency and mean distances of v1: 67.9%, 4.53 cm; v2: 60.7%, 6.97 cm, v3: 50%, 9.58 cm; v4: 35.7%, 10.89 cm; v5: 25%, 12.65 cm; v6: 10.7%, 16.94 cm; v7: 3.6%, 18.7 cm proximal to the tuber calcanei. However, due to the small diameter of these branches, by anatomic dissection no nutrient arteries commencing from the TA could be detected. On the other hand, a maximum of 7 vessels originating from the TP, larger than the former vessels, had been also revealed by anatomic dissection (frequency and mean distances, v1: 100%, 6.8 cm; v2: 82.1%, 7.7 cm; v3: 71.4%, 9.5 cm; v4: 35.7%, 11.3 cm; v5: 17.9%, 9.9 cm; v6: 7.1, 10.5 cm; v7: 3.6%, 12.0 cm). Conclusion: A dense net of small arteries inserts into the paratenon of the Achilles tendon in its lower 20 cm. The angiographic method was more specific and showed vessels that could not be identified as arteries originating from the TA by macroscopic anatomic dissection.

258

Dominance of the odometer over serial landmark learning in honeybee navigation  

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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

259

Anatomical variation in the position of the greater palatine foramen.  

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The present study measured the position of the greater palatine foramen relative to adjacent anatomical landmarks in Brazilian skulls. The perpendicular distance of the greater palatine foramen to the midline maxillary suture in Brazilian skulls was about 14 mm and the distance of greater palatine foramen to the incisive foramen was approximately 36 mm. The distance of greater palatine foramen to the posterior border of the hard palate was approximately 3 mm, and the mean angle between the midline maxillary suture and the line from the incisive foramen and the greater palatine foramen was 22.71 degrees . In almost 70% of the cases, the greater palatine foramen opened in an anterior direction. The mean palatine length was approximately 52 mm. In the greater majority of the skulls (93.81%), the greater palatine foramina were opposite or distal to the maxillary third molar. These data will be helpful in comparing these skulls to those from various other regions as well as comparing skulls of different races. It can also provide professionals with anatomical references, in order to block the maxillary division of the trigeminal nerve through the greater palatine foramen. Our results would help clinicians locate the greater palatine foramen in patients with and without upper molars. PMID:20339241

Chrcanovic, Bruno R; Custódio, Antônio L N

2010-03-01

260

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.)

 
 
 
 
261

Integrating anatomical pathology to the healthcare enterprise.  

Science.gov (United States)

For medical decisions, healthcare professionals need that all required information is both correct and easily available. We address the issue of integrating anatomical pathology department to the healthcare enterprise. The pathology workflow from order to report, including specimen process and image acquisition was modeled. Corresponding integration profiles were addressed by expansion of the IHE (Integrating the Healthcare Enterprise) initiative. Implementation using respectively DICOM Structured Report (SR) and DICOM Slide-Coordinate Microscopy (SM) was tested. The two main integration profiles--pathology general workflow and pathology image workflow--rely on 13 transactions based on HL7 or DICOM standard. We propose a model of the case in anatomical pathology and of other information entities (orders, image folders and reports) and real-world objects (specimen, tissue samples, slides, etc). Cases representation in XML schemas, based on DICOM specification, allows producing DICOM image files and reports to be stored into a PACS (Picture Archiving and Communication System. PMID:17108550

Daniel-Le Bozec, Christel; Henin, Dominique; Fabiani, Bettina; Bourquard, Karima; Ouagne, David; Degoulet, Patrice; Jaulent, Marie-Christine

2006-01-01

262

Application of the Restriction Landmark Genome Scanning (RLGS Method for Analysis of Genetic Diversity between Asian and African Sorghum  

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Full Text Available Restriction Landmark Genome Scanning (RLGS used to detect large numbers of restriction landmarks in a single experiment andapplied to analyze the genetic diversity of Asian and African sorghum accessions. This method is one of the genome analysistools based on the concept that restriction enzyme sites can serve as landmarks throughout a genome. RLGS uses direct endlabelingof the genomic DNA digested with a rare-cutting restriction enzyme and high-resolution two-dimensionalelectrophoresis. It has an advantage of providing precise information on a spot intensity that reflects the copy number ofrestriction landmarks and to visualize differences in methylation levels across the genome. RLGS becomes very useful for doingwhole genome scans that equals the work of thousands of polymerase chain reactions. A study was carried out using Sorghumaccessions collected from countries viz., Morocco, Nigeria, Sudan, South Africa, Japan, South Korea, and China. Onerepresentative sample was chosen from a country for analysis carried out at National Institute of Agrobiological Sciences(NIAS. Two dimensional spot images for seven accessions obtained and spot intensities were scanned. Totally, 119 spots weredetected of which 95 spots observed as polymorphic and 24 as non polymorphic. Unique presence and null spots werespecifically detected in all accessions taken for study. A total of 37 unique spots and 12 null spots, detected in this experiment.Principal Coordinate Analysis indicated, four African accessions scattered in the diagram were diverse and three Asianaccessions closely distributed with narrow diversity. The phylogenetic tree showed that Sudan and Nigerian accessions weredistant while Chinna, Japan and Korea accessions had close proximity

Hisato Okuizumi*, Tomotsugu Noguchi, Tatsuya Saguchi,Takuma Fujita, Eri Nonaka, Shinsuke Yamanaka, Koffi Kombate, Subbarayan Sivakumar , Kulandaivelu Ganesamurthy, Yasufumi Murakami

2010-07-01

263

Maximized Posteriori Attributes Selection from Facial Salient Landmarks for Face Recognition  

Science.gov (United States)

This paper presents a robust and dynamic face recognition technique based on the extraction and matching of devised probabilistic graphs drawn on SIFT features related to independent face areas. The face matching strategy is based on matching individual salient facial graph characterized by SIFT features as connected to facial landmarks such as the eyes and the mouth. In order to reduce the face matching errors, the Dempster-Shafer decision theory is applied to fuse the individual matching scores obtained from each pair of salient facial features. The proposed algorithm is evaluated with the ORL and the IITK face databases. The experimental results demonstrate the effectiveness and potential of the proposed face recognition technique also in case of partially occluded faces.

Gupta, Phalguni; Kisku, Dakshina Ranjan; Sing, Jamuna Kanta; Tistarelli, Massimo

264

Maximized Posteriori Attributes Selection from Facial Salient Landmarks for Face Recognition  

CERN Document Server

This paper presents a robust and dynamic face recognition technique based on the extraction and matching of devised probabilistic graphs drawn on SIFT features related to independent face areas. The face matching strategy is based on matching individual salient facial graph characterized by SIFT features as connected to facial landmarks such as the eyes and the mouth. In order to reduce the face matching errors, the Dempster-Shafer decision theory is applied to fuse the individual matching scores obtained from each pair of salient facial features. The proposed algorithm is evaluated with the ORL and the IITK face databases. The experimental results demonstrate the effectiveness and potential of the proposed face recognition technique also in case of partially occluded faces.

Gupta, Phalguni; Sing, Jamuna Kanta; Tistarelli, Massimo

2010-01-01

265

Anatomical and functional imaging in endocrine hypertension  

Science.gov (United States)

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 used in patients with endocrine hypertension. PMID:23087854

Chaudhary, Vikas; Bano, Shahina

2012-01-01

266

3D CT-based cephalometric analysis: 3D cephalometric theoretical concept and software  

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We present an original three-dimensional cephalometric analysis based on a transformation of a classical two dimensional topological cephalometry. To validate the three-dimensional cephalometric CT based concept we systematically compared the alignments of anatomic structures. We used digital lateral radiography to perform the classical two-dimensional cephalometry, and a three-dimensional CT surface model for the three-dimensional cephalometry. Diagnoses based on both two-dimensional and three-dimensional analyses were adequate, but the three-dimensional analysis gave more information such as the possibility of comparing the right and left side of the skull. Also the anatomic structures were not superimposed which improved the visibility of the reference landmarks. We demonstrated that three-dimensional analysis gives the same results as two-dimensional analysis using the same skull. We also present possible applications of the method. (orig.)

Olszewski, R.; Mahy, P.; Reychler, H. [Universite Catholique de Louvain, Department of Oral and Maxillofacial Surgery, Saint Luc University Clinics, Brussels (Belgium); Cosnard, G. [Universite Catholique de Louvain, Department of Radiology, Saint Luc University Clinics, Brussels (Belgium); Macq, B. [Universite Catholique de Louvain, Communications and Remote Sensing Laboratory, Faculty of Engineering, Louvain-la-Neuve (Belgium)

2006-11-15

267

3D CT-based cephalometric analysis: 3D cephalometric theoretical concept and software  

International Nuclear Information System (INIS)

We present an original three-dimensional cephalometric analysis based on a transformation of a classical two dimensional topological cephalometry. To validate the three-dimensional cephalometric CT based concept we systematically compared the alignments of anatomic structures. We used digital lateral radiography to perform the classical two-dimensional cephalometry, and a three-dimensional CT surface model for the three-dimensional cephalometry. Diagnoses based on both two-dimensional and three-dimensional analyses were adequate, but the three-dimensional analysis gave more information such as the possibility of comparing the right and left side of the skull. Also the anatomic structures were not superimposed which improved the visibility of the reference landmarks. We demonstrated that three-dimensional analysis gives the same results as two-dimensional analysis using the same skull. We also present possible applications of the method. (orig.)

268

ROLE OF ANATOMICAL OBSTRUCTION IN THE PATHOGENESIS OF CHRONIC SINUSITIS  

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Full Text Available 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 is caused by more than one anatomical factor.

Balasubramanian Thiagarajan

2012-08-01

269

Assessing the role of the biomaterial Aquavene in patient reactions to Landmark midline catheters.  

Science.gov (United States)

Landmark midline catheters (Menlo Care, Inc., Palo Alto, CA) provide peripheral venous access for the infusion of medications or fluids. They are constructed of an inner layer of polyurethane and an outer layer of the biomaterial Aquavene, a blend of polyurethane and polyethylene oxide to which butylated hyroxyanisole (BHA), butylated hydroxytoluene (BHT), and triallyl-s-triazine trione (TTT) are added. Once inside the vein, the Aquavene material becomes hydrated and the catheter swells resulting in minimal trauma to the vein. It is well recognized that some patients experience reactions to catheterization. Recent reports of hypersensitivity-like reactions in some patients catheterized with Landmark catheters have prompted the manufacturer to reexamine biocompatibility data and clinical data to assess whether Aquavene was the source of the patient responses. None of the biocompatibility studies provided by Menlo Care in support of U.S. registration and marketing of Aquavene-based catheters demonstrated any tendency for Aquavene or material extracted from Aquavene to invoke an immunological or toxicological response. Examination of potential catheter residuals revealed that significant amounts of BHA and BHT were unlikely to be released from the catheters during expected use. The amounts of polyethylene oxide and TTT expected to be released during the first few minutes after catheter insertion (when most of the patient reactions were reported) are almost 92,500 and 270,000 times lower, respectively, than nontoxic animal exposures. These analyses do not support chemically mediated toxicity as an explanation for the adverse events experienced by some patients. A review of the postmarket surveillance data on Aquavene-based catheters revealed that the reported events were not consistent with a hypersensitivity (immunogenic) response to the biomaterial. The rare reported adverse events tend to occur quickly, most often after flushing of the catheter, and resolve quickly, even when the catheter remains in place. Determining the frequency and severity of adverse events reported in association with the use of Landmark catheters will ultimately require a controlled prospective study, preferably one with a concurrent control group using alternative products. PMID:9056501

Silverstein, B; Witkin, K M; Frankos, V H; Terr, A I

1997-02-01

270

Probabilistic anatomical labeling of brain structures using statistical probabilistic anatomical maps  

International Nuclear Information System (INIS)

The use of statistical parametric mapping (SPM) program has increased for the analysis of brain PET and SPECT images. Montreal neurological institute (MNI) coordinate is used in SPM program as a standard anatomical framework. While the most researchers look up Talairach atlas to report the localization of the activations detected in SPM program, there is significant disparity between MNI templates and Talairach atlas. That disparity between Talairach and MNI coordinates makes the interpretation of SPM result time consuming, subjective and inaccurate. The purpose of this study was to develop a program to provide objective anatomical information of each x-y-z position in ICBM coordinate. Program was designed to provide the anatomical information for the given x-y-z position in MNI coordinate based on the statistical probabilistic anatomical map (SPAM) images of ICBM. When x-y-z position was given to the program, names of the anatomical structures with non-zero probability and the probabilities that the given position belongs to the structures were tabulated. The program was coded using IDL and JAVA language for the easy transplantation to any operating system or platform. Utility of this program was shown by comparing the results of this program to those of SPM program. Preliminary validation study was performed by applying this program to the analysis of PET brain activation study of human memory in which the anatomical information on the activated areas are previouslytion on the activated areas are previously known. Real time retrieval of probabilistic information with 1 mm spatial resolution was archived using the programs. Validation study showed the relevance of this program: probability that the activated area for memory belonged to hippocampal formation was more than 80%. These programs will be useful for the result interpretation of the image analysis performed on MNI coordinate, as done in SPM program

271

An evaluation of cellular neural networks for the automatic identification of cephalometric landmarks on digital images.  

Science.gov (United States)

Several efforts have been made to completely automate cephalometric analysis by automatic landmark search. However, accuracy obtained was worse than manual identification in every study. The analogue-to-digital conversion of X-ray has been claimed to be the main problem. Therefore the aim of this investigation was to evaluate the accuracy of the Cellular Neural Networks approach for automatic location of cephalometric landmarks on softcopy of direct digital cephalometric X-rays. Forty-one, direct-digital lateral cephalometric radiographs were obtained by a Siemens Orthophos DS Ceph and were used in this study and 10 landmarks (N, A Point, Ba, Po, Pt, B Point, Pg, PM, UIE, LIE) were the object of automatic landmark identification. The mean errors and standard deviations from the best estimate of cephalometric points were calculated for each landmark. Differences in the mean errors of automatic and manual landmarking were compared with a 1-way analysis of variance. The analyses indicated that the differences were very small, and they were found at most within 0.59 mm. Furthermore, only few of these differences were statistically significant, but differences were so small to be in most instances clinically meaningless. Therefore the use of X-ray files with respect to scanned X-ray improved landmark accuracy of automatic detection. Investigations on softcopy of digital cephalometric X-rays, to search more landmarks in order to enable a complete automatic cephalometric analysis, are strongly encouraged. PMID:19753320

Leonardi, Rosalia; Giordano, Daniela; Maiorana, Francesco

2009-01-01

272

Development and application of a portable manual non-contact-type goniometric instrument for measuring human anatomical angular parameters.  

Science.gov (United States)

Several manual contact-type goniometric instruments have previously been developed to measure joint range of motion (ROM) during physical-therapy evaluation. These include the universal goniometer and the gravity-dependent goniometer, or inclinometer, which are used to measure the ROM angle of a subject in a fully erect posture. Here, we developed a manual non-contact-type portable goniometric instrument for the measurement of anatomical angular parameters based on the principle of spot irradiation by using laser markers. The accuracy of the developed instrument was tested and its performance was compared with that of a contact-type instrument by using a skeletal model (14 static angle assessments), a free posture manikin (18 static angle assessments), and healthy human bodies (5 males and 5 females; 11 dynamic angle assessments). Measurement errors were examined also. When taking the measurements, a visual landmark-detection method was used in place of the conventional palpation method, which is inappropriate for a non-contact measuring system. The instrument developed here is applicable for practical non-contact goniometry and ROM measurements. PMID:22609063

Susato, Shin-ichi

2013-02-01

273

Brain activity during landmark and line bisection tasks  

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Full Text Available Neglect patients bisect lines far rightward of center whereas normal subjects typically bisect lines with a slight leftward bias supporting a right hemisphere bias for attention allocation. We used fMRI to assess the brain regions related to this function in normals, using two complementary tasks. In the Landmark task subjects were required to judge whether or not a presented line was bisected correctly. During the line bisection task, subjects moved a cursor and indicated when it reached the center of the line. The conjunction of BOLD activity for both tasks showed right lateralized intraparietal sulcus and lateral peristriate cortex activity. The results provide evidence that predominantly right hemisphere lateralized processes are engaged in normal subjects during tasks that are failed in patients with unilateral neglect and highlight the importance of a right fronto-parietal network in attention allocation.

MetehanCicek

2009-05-01

274

Clinically Significant Anatomical Variants of the Paranasal Sinuses  

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Full Text Available Objective: Anatomic structural variations of the paranasal sinuses have a practical significance during surgical procedures conducted on the sinuses by otolaryngologists. This study aims to evaluate the prevalence of clinically significant anatomical variations of the paranasal sinuses. Methods: A prospective analysis of 435 computed tomography (CT examinations of adult Omani patients was conducted to determine the prevalence of clinically significant anatomical variations of the paranasal sinuses. A total of 360 CT scans were included from January 2009 to January 2010. Results: The findings showed abnormal Agger nasi cells in 49% of cases (95% CI: 44-54%, concha bullosa in 49% (95% CI: 44-54%, Haller cells in 24% (95% CI: 18-31%, asymmetry in anterior ethmoidal roof 32% (CI: 29-37%, Onodi cells in 8% (CI: 5%-10%. The type of skull base were as follows; Type 1 was 30% (n=107; 95% CI: 25-35%, Type 2 was 34% (n=123; 95% CI: 29-39, and Type 3 was 36% (n=130; 95% CI: 31-41%. Many other surgically significant anatomical variations in small numbers (1-3 were incidentally identified. Conclusion: Knowledge of the presence of anatomical variations of the sinuses has a clinical significance as it minimizes the potential for surgical complications. There is an ethnical difference in the prevalence of anatomical variations. Further studies of anatomical variations with clinical disease correlations are needed.

Deepa Bhargava

2014-03-01

275

Applying the functional abnormality ontology pattern to anatomical functions  

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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

276

Morphometric analysis of facial landmark data to characterize the facial phenotype associated with fetal alcohol syndrome  

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Procrustes analysis and principal component analysis were applied to stereo-photogrammetrically obtained landmarks to compare the facial features associated with fetal alcohol syndrome (FAS) in subjects with FAS and normal controls. Two studies were performed; both compared facial landmark data of FAS and normal subjects, but they differed in the number of landmarks chosen. The first study compared landmarks representing palpebral fissure length, upper lip thinness and philtrum smoothness and revealed no significant difference in shape. The second study added to the landmarks used in the first those affected by mid-face hypoplasia, and revealed significant differences in shape between the two groups, broadly confirming the FAS gestalt reported in the literature. Some disagreement in the characteristic FAS facial shape between our results and those reported in the literature may be due to ethnic variation. PMID:17310546

Mutsvangwa, Tinashe; Douglas, Tania S

2007-01-01

277

Quantification of organ motion based on an adaptive image-based scale invariant feature method  

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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

278

Quantification of organ motion based on an adaptive image-based scale invariant feature method  

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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.

Paganelli, Chiara [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, piazza L. Da Vinci 32, Milano 20133 (Italy); Peroni, Marta [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, piazza L. Da Vinci 32, Milano 20133, Italy and Paul Scherrer Institut, Zentrum für Protonentherapie, WMSA/C15, CH-5232 Villigen PSI (Italy); Baroni, Guido; Riboldi, Marco [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, piazza L. Da Vinci 32, Milano 20133, Italy and Bioengineering Unit, Centro Nazionale di Adroterapia Oncologica, strada Campeggi 53, Pavia 27100 (Italy)

2013-11-15

279

Differentiating the impact of anatomic and non-anatomic liver resection on early recurrence in patients with Hepatocellular Carcinoma  

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Full Text Available Abstract Background For Hepatocellular Carcinoma (HCC treated with hepatectomy, the extent of the resection margin remains controversial and data available on its effect on early tumor recurrence are very few and contradictory. The purpose of this study was to compare the impact of the type of resection (anatomic versus non-anatomic on early intra-hepatic HCC recurrence in patients with solitary HCC and preserved liver function. Methods Among 53 patients with similar clinico-pathologic data who underwent curative liver resection for HCC between 2000 and 2006, 28 patients underwent anatomic resection of at least one liver segment and 25 patients underwent limited resection with a margin of at least 1 cm. Results After a close follow-up period of 24 months, no difference was detected in recurrence rates between the anatomic (35.7% and the non-anatomic (40% groups in either univariate (p = 0.74 and multivariate (p = 0.65 analysis. Factors contributing to early recurrence were tumor size (p = 0.012 and tumor stage including vascular invasion (p = 0.009. Conclusion The choice of the type of resection for HCC should be based on the maintenance of adequate hepatic reserve. The type of resection (anatomic vs non-anatomic was found not to be a risk factor for early tumor recurrence.

Giovinazzo Francesco

2010-05-01

280

Study on the Construction of a High-definition Whole-body Voxel Model based on Cadaver's Color Photographic Anatomical Slice Images and Monte Carlo Dose Calculations  

International Nuclear Information System (INIS)

Ajou University School of Medicine made the serially sectioned anatomical images from the Visible Korean Human (VKH) Project in Korea. The VKH images, which are the high-resolution color photographic images, show the organs and tissues in the human body very clearly at 0.2 mm intervals. In this study, we constructed a high-quality voxel model (VKH-Man) with a total of 30 organs and tissues by manual and automatic segmentation method using the serially sectioned anatomical image data from the Visible Korean Human (VKH) project in Korea. The height and weight of VKH-Man voxel model is 164 cm and 57.6 kg, respectively, and the voxel resolution is 1.875 x 1.875 x 2 mm3. However, this voxel phantom can be used to calculate the organ and tissue doses of only one person. Therefore, in this study, we adjusted the voxel phantom to the 'Reference Korean' data to construct the voxel phantom that represents the radiation workers in Korea. The height and weight of the voxel model (HDRK-Man) that is finally developed are 171 cm and 68 kg, respectively, and the voxel resolution is 1.981 x 1.981 x 2.0854 mm3. VKH-Man and HDRK-Man voxel model were implemented in a Monte Carlo particle transport simulation code for calculation of the organ and tissue doses in various irradiation geometries. The calculated values were compared with each other to see the effect of the adjustment and also compared with other computational models (KTMAN-2, ICRP-74 and VIP-Man). According to the results, the adjustment of the voxel model was found hardly affect the dose calculations and most of the organ and tissue equivalent doses showed some differences among the models. These results shows that the difference in figure, and organ topology affects the organ doses more than the organ size. The calculated values of the effective dose from VKH-Man and HDRK-Man according to the ICRP-60 and upcoming ICRP recommendation were compared. For the other radiation geometries (AP, LLAT, RLAT) except for PA radiation geometry, the effective dose according to the upcoming ICRP recommendation was somewhat larger than that according to the ICRP-60. This seems due to change of the tissue weighting factor in the upcoming ICRP recommendation. The developed phantoms (VKH-Man and HDRK-Man) are expected to be used to estimate the radiation risk of only Korean in external and internal dosimetry. Dose conversion coefficients calculated in this study are also expected to be used in radiation protection assessment of Korean since those were distinguished from those of the western

 
 
 
 
281

Quantifying anatomical shape variations in neurological disorders.  

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We develop a multivariate analysis of brain anatomy to identify the relevant shape deformation patterns and quantify the shape changes that explain corresponding variations in clinical neuropsychological measures. We use kernel Partial Least Squares (PLS) and formulate a regression model in the tangent space of the manifold of diffeomorphisms characterized by deformation momenta. The scalar deformation momenta completely encode the diffeomorphic changes in anatomical shape. In this model, the clinical measures are the response variables, while the anatomical variability is treated as the independent variable. To better understand the "shape-clinical response" relationship, we also control for demographic confounders, such as age, gender, and years of education in our regression model. We evaluate the proposed methodology on the Alzheimer's Disease Neuroimaging Initiative (ADNI) database using baseline structural MR imaging data and neuropsychological evaluation test scores. We demonstrate the ability of our model to quantify the anatomical deformations in units of clinical response. Our results also demonstrate that the proposed method is generic and generates reliable shape deformations both in terms of the extracted patterns and the amount of shape changes. We found that while the hippocampus and amygdala emerge as mainly responsible for changes in test scores for global measures of dementia and memory function, they are not a determinant factor for executive function. Another critical finding was the appearance of thalamus and putamen as most important regions that relate to executive function. These resulting anatomical regions were consistent with very high confidence irrespective of the size of the population used in the study. This data-driven global analysis of brain anatomy was able to reach similar conclusions as other studies in Alzheimer's disease based on predefined ROIs, together with the identification of other new patterns of deformation. The proposed methodology thus holds promise for discovering new patterns of shape changes in the human brain that could add to our understanding of disease progression in neurological disorders. PMID:24667299

Singh, Nikhil; Fletcher, P Thomas; Preston, J Samuel; King, Richard D; Marron, J S; Weiner, Michael W; Joshi, Sarang

2014-04-01

282

ANATOMICAL PROPERTIES OF PLANTAGO ARENARIA  

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Full Text Available Psammophytes are marked by a number of adaptations that enable them to exist in the hard environmental conditions of the sand habitats. In this study, the anatomical characteristics of Plantago arenaria were examined. Studies were conducted to assess the diversity of anatomical adaptations of vegetative organs in this taxa. Results are presented with original photographs. The analysis of leaf anatomy in P. arenaria showed that the leaves contained a contained xeromorphic traits. Arbuscular mycorrhizal symbiosis seems to be critical for their survival.

Nicoleta IANOVICI

2011-01-01

283

Steps towards automatic building of anatomical atlases  

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This paper presents a general scheme for the building of anatomical atlases. We propose to use specific and stable features, the crest lines (or ridge lines) which are automatically extracted from 3D images by differential geometry operators. We have developed non-rigid registration techniques based on polynomial transformations to find correspondences between lines. We got encouraging results for the building of atlases of the crest lines of the skull and of the brain based on several CT-Scan and MRI images of different patients.

Subsol, Gerard; Thirion, Jean-Philippe; Ayache, Nicholas

1994-09-01

284

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

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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. Clin. Anat. 27:1178-1184, 2014. © 2014 Wiley Periodicals, Inc. PMID:24863980

Konschake, Marko; Fritsch, Helga

2014-11-01

285

Internal jugular vein cannulation: an ultrasound-guided technique versus a landmark-guided technique  

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Full Text Available OBJECTIVES: To compare the landmark-guided technique versus the ultrasound-guided technique for internal jugular vein cannulation in spontaneously breathing patients. METHODS: A total of 380 patients who required internal jugular vein cannulation were randomly assigned to receive internal jugular vein cannulation using either the landmark- or ultrasound-guided technique in Bursa, Uludag University Faculty of Medicine, between April and November, 2008. Failed catheter placement, risk of complications from placement, risk of failure on first attempt at placement, number of attempts until successful catheterization, time to successful catheterization and the demographics of each patient were recorded. RESULTS: The overall complication rate was higher in the landmark group than in the ultrasound-guided group (p < 0.01. Carotid puncture rate and hematoma were more frequent in the landmark group than in the ultrasound-guided group (p < 0.05. The number of attempts for successful placement was significantly higher in the landmark group than in the ultrasound-guided group, which was accompanied by a significantly increased access time observed in the landmark group (p < 0.05 and p < 0.01, respectively. Although there were a higher number of attempts, longer access time, and a more frequent complication rate in the landmark group, the success rate was found to be comparable between the two groups. CONCLUSION: The findings of this study indicate that internal jugular vein catheterization guided by real-time ultrasound results in a lower access time and a lower rate of immediate complications.

Gurkan Turker

2009-01-01

286

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

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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

287

Knowledge of skull base anatomy and surgical implications of human sacrifice among pre-Columbian Mesoamerican cultures.  

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Human sacrifice became a common cultural trait during the advanced phases of Mesoamerican civilizations. This phenomenon, influenced by complex religious beliefs, included several practices such as decapitation, cranial deformation, and the use of human cranial bones for skull mask manufacturing. Archaeological evidence suggests that all of these practices required specialized knowledge of skull base and upper cervical anatomy. The authors conducted a systematic search for information on skull base anatomical and surgical knowledge among Mesoamerican civilizations. A detailed exposition of these results is presented, along with some interesting information extracted from historical documents and pictorial codices to provide a better understanding of skull base surgical practices among these cultures. Paleoforensic evidence from the Great Temple of Tenochtitlan indicates that Aztec priests used a specialized decapitation technique, based on a deep anatomical knowledge. Trophy skulls were submitted through a stepwise technique for skull mask fabrication, based on skull base anatomical landmarks. Understanding pre-Columbian Mesoamerican religions can only be realized by considering them in their own time and according to their own perspective. Several contributions to medical practice might have arisen from anatomical knowledge emerging from human sacrifice and decapitation techniques. PMID:22853827

Lopez-Serna, Raul; Gomez-Amador, Juan Luis; Barges-Coll, Juan; Arriada-Mendicoa, Nicasio; Romero-Vargas, Samuel; Ramos-Peek, Miguel; Celis-Lopez, Miguel Angel; Revuelta-Gutierrez, Rogelio; Portocarrero-Ortiz, Lesly

2012-08-01

288

Anatomical structure of Polystichum Roth ferns rachises  

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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.

Tyshchenko, Oksana V.; Vasheka, Olena V.; Polyshchuk, Iryna O.

2012-01-01

289

77 FR 14420 - Landmarks Committee of the National Park System Advisory Board Meeting  

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...May 16 at 9 a.m. Location: The Charles Sumner School Museum and Archives, 3rd...FURTHER INFORMATION CONTACT: Patricia Henry, National Historic Landmarks Program...Telephone (202) 354-2216; Email: Patty_Henry@nps.gov. SUPPLEMENTARY...

2012-03-09

290

36 CFR 62.4 - Natural landmark designation and recognition process.  

Science.gov (United States)

...that may affect the area's natural values, integrity, or other matters of...owner's interest in protecting and managing the area in a manner that prevents the loss or deterioration of the natural values on which landmark designation is...

2010-07-01

291

Numerical landmarks are useful--except when they're not.  

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Placing landmarks on number lines, such as marking each tenth on a 0-1 line with a hatch mark and the corresponding decimal, has been recommended as a useful tool for improving children's number sense. Four experiments indicated that some landmarks do have beneficial effects, others have harmful effects, and yet others have no effects on representations of common fractions (N/M). The effects of the landmarks were seen not only on the number line task where they appeared but also on a subsequent magnitude comparison task and on correlations with mathematics achievement tests. Landmarks appeared to exert their effects through the encodings and strategies that they promoted. Theoretical and educational implications are discussed. PMID:24382407

Siegler, Robert S; Thompson, Clarissa A

2014-04-01

292

An Evaluation of Cellular Neural Networks for the Automatic Identification of Cephalometric Landmarks on Digital Images  

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Several efforts have been made to completely automate cephalometric analysis by automatic landmark search. However, accuracy obtained was worse than manual identification in every study. The analogue-to-digital conversion of X-ray has been claimed to be the main problem. Therefore the aim of this investigation was to evaluate the accuracy of the Cellular Neural Networks approach for automatic location of cephalometric landmarks on softcopy of direct digital cephalometric X-rays. Forty-one, di...

Rosalia Leonardi; Daniela Giordano; Francesco Maiorana

2009-01-01

293

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

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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

294

A comparison of two methods for natural landmark classification with Biosonar  

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Most current sonar systems for mobile robots only yield time of flight distance information produced by measuring the time of a single sonar pulse. However, sonar systems of animals like sonar bats are much more sophisticated, allowing to recognize not only the shape, but also the type of landmark trees that they use during their nocturnal flights. In this paper we compare two methods for natural landmark classification by a biomimetic sonar consisting of one sender (mouth) and two receivers ...

Wang, Maosen; Zell, Andreas; Mu?ller, Rolf; Wilhelm-schickard-institut Fu?r Informatik, Tu?bingen

2004-01-01

295

Influence of Landmarks on Spatial Memory in Short-nosed Fruit Bat, Cynopterus sphinx.  

Science.gov (United States)

In order to study the relationship between landmarks and spatial memory in short-nosed fruit bat, Cynopterus sphinx (Megachiroptera, Pteropodidae), we simulated a foraging environment in the laboratory. Different landmarks were placed to gauge the spatial memory of C. sphinx. We changed the number of landmarks every day with 0 landmarks again on the fifth day (from 0, 2, 4, 8 to 0). Individuals from the control group were exposed to the identical artificial foraging environment, but without landmarks. The results indicated that there was significant correlation between the time of the first foraging and the experimental days in both groups (Pearson Correlation: experimental group: r=-0.593, P0.05), but there was significant correlation between the success rates of foraging and the experimental days in the control groups (Pearson Correlation: r=0.445, P0.05); also, there was no significant difference in success rates of foraging between these two groups (GLM: F(0.05,1 )=0.849, P>0.05). The results of our experiment suggest that spatial memory in C. sphinx was formed gradually and that the placed landmarks appeared to have no discernable effects on the memory of the foraging space. PMID:20545006

Zeng, Yu; Zhang, Xin-Wen; Zhu, Guang-Jian; Gong, Yan-Yan; Yang, Jian; Zhang, Li-Biao

2010-04-01

296

Anatomic variations on PNS CT  

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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) 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.

Lee, Kuk Jin; Youn, Eun Kyung; Lee, Young Uk; Kim, Dong Hyun; Suh, Jong Dae [Koryo General Hospital, Seoul (Korea, Republic of)

1994-09-15

297

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) 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

298

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.

299

Insite: Canada's landmark safe injecting program at risk  

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Full Text Available Abstract InSite is North Americas first supervised injection site and a landmark public heath initiative operating in Vancouver since 2003. The program is a vital component of that cities internationally recognized harm reduction approach to its serious problems with drugs, crime, homelessness and AIDS. InSite currently operates under a waiver of Federal rules that allow it to provide services as a research project. An extensive evaluation has produced very positive results for thousands of users. Normally such strong evidence documenting the successes of such a program, and the medical and public health significance of these positive outcomes, would be the basis for celebration and moves to expand the model and provide similar services elsewhere in Canada. Instead, there is a distinct possibility that InSite will be closed by the newly elected Canadian Prime Minister Paul Harper – a conservative who has traveled to the US to visit George WQ Bush and come back antagonistic to harm reduction in all its forms. Because InSites federal waiver is expiring and up for renewal in September, the fear is that Mr. Harpers will not renew the approval and that the program will be forced to close down. The risks associated with the potential closure of InSite need to be fully understood. This editorial lays out these public health risks and the associated economic impact if InSite were to be closed. In addition to preventable deaths and disease, InSites closure will cost Vancouver and British Columbia between $3.8 and $ 8.8 million in preventable health care expenses over the next two years.

Drucker Ernest

2006-08-01

300

Selenium-based digital radiography of the cervical spine. Comparison with screen-film radiography for the depiction of anatomic details; Digitale Selenradiographie der HWS. Vergleich mit der konventionellen Film-Folien-Radiographie bezueglich der Erkennbarkeit anatomischer Details  

Energy Technology Data Exchange (ETDEWEB)

Purpose: To compare selenium-based digital radiography with conventional screen-film radiography of the cervical spine. Materials and Methods: In a prospective study X-ray images of the cervical spine were obtained in 25 patients using selenium-based digital radiography and conventional screen-film radiography. All images were clinically indicated. Selenium-based digital radiography and conventional screen-film radiography were used in a randomized order. Four radiologists independently evaluated all 50 examinations for the visibility of 76 anatomic details according to a five-level confidence scale (1=not visible, 5=very good visibility). From the evaluation of these anatomic details scores for the upper and middle cervical spine, the cervicothoracic junction and the cervical soft tissues were calculated. The scores for selenium-based digital radiography and conventional screen-film radiography were compared using Wilcoxon's signed rank test. Results: From a total of 15,200 observations (608 per patient) the following scores were calculated for selenium-based digital radiography and for screen-film radiography, respectively: Upper cervical spine 3.88 and 3.94; middle cervical spine 4.60 and 4.48; cervico-thoracic junction 3.64 and 2.62; cervical soft tissue 4.47 and 3.46. The differences between the last two scores were statistically significant (p<0.05). Conclusion: the use of selenium-based digital radiography is superior to conventional screen-film radiography in the depiction of anatomic details of the cervicothoracic junction and the cervical soft tissues. (orig.) [German] Zielsetzung: Bietet der Einsatz eines digitalen Selendetektorsystems zur Roentgenuntersuchung des HWS Vorteile gegenueber einem konventionellen Film-Folien-Systems? Material und Methoden: Prospektiv wurden bei 25 Patienten Roentgenaufnahmen der HWS im Verlauf mittels digitaler Selenradiographie und mittels konventioneller Film-Folien-Radiographie angefertigt. Alle Aufnahmen waren klinisch indiziert. Die Reihenfolge, in der Selenradiographie oder Film-Folien-System zum Einsatz kamen, war randomisiert. 4 Radiologen beurteilten unabhaengig voneinander auf allen 50 Untersuchungen die Sichtbarkeit 76 anatomischer Strukturen unter Verwendung einer 5-teiligen Skala (1=nicht sichtbar, 5=sehr gut sichtbar). Aus den Bewertungen der anatomischen Strukturen wurden Scores fuer die Strukturen der oberen und der mittleren HWS, des zervikothorakalen Ueberganges und der zervikalen Weichteilstrukturen errechnet. Die Scores fuer die Selenradiographie und die Film-Folien-Radiographie wurden mittels Wilcoxon-Text fuer verbundene Stichproben mit zweiseitiger Fragestellung verglichen. Ergebnisse: Aus insgesamt 15 200 Einzelbeobachtungen (608 pro Patient) ergaben sich folgende Scores fuer die Selenradiographie bzw. die Film-Folien-Radiographie: Obere HWS 3,88 bzw. 3,94; mittlere HWS 4,60 bzw. 4,48; zervikothorakaler Uebergang 3,64 bzw. 2,62; zervikale Weichteilstrukturen 4,47 bzw. 3,46. Die Unterschiede zwischen den beiden letztgenannten Scores waren statistisch signifikant (p<0,05). Schlussfolgerung: Der Einsatz eines digitalen Selendetektorsystems bietet Vorteile gegenueber dem konventionellen Film-Folien-System hinsichtlich der Erkennbarkeit anatomischer Strukturen im zervikothorakalen Uebergang und der zervikalen Weichteile. (orig.)

Ludwig, K.; Diederich, S.; Wormanns. D.; Link, T.M.; Lenzen, H.; Heindel, W. [Muenster Univ. (Germany). Inst. fuer Klinische Radiologie

2002-08-01

 
 
 
 
301

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

Directory of Open Access Journals (Sweden)

Full Text Available Computational models of neural networks can be based on a variety of different parameters. These parameters include, for example, the 3d shape of neuron layers, the neurons' spatial projection patterns, spiking dynamics and neurotransmitter systems. While many well-developed approaches are available to model, for example, the spiking dynamics, there is a lack of approaches for modeling the anatomical layout of neurons and their projections. We present a new method, called Parametric Anatomical Modeling (PAM, to fill this gap. PAM can be used to derive network connectivities and conduction delays from anatomical data, such as the position and shape of the neuronal layers and the dendritic and axonal projection patterns. Within the PAM framework, several mapping techniques between layers can account for a large variety of connection properties between pre- and post-synaptic neuron layers. PAM is implemented as a Python tool and integrated in the 3d modeling software Blender. We demonstrate on a 3d model of the hippocampal formation how PAM can help reveal complex properties of the synaptic connectivity and conduction delays, properties that might be relevant to uncover the function of the hippocampus. Based on these analyses, two experimentally testable predictions arose: i the number of neurons and the spread of connections is heterogeneously distributed across the main anatomical axes, ii the distribution of connection lengths in CA3-CA1 differ qualitatively from those between DG-CA3 and CA3-CA3. Models created by PAM can also serve as an educational tool to visualize the 3d connectivity of brain regions. The low-dimensional, but yet biologically plausible, parameter space renders PAM suitable to analyse allometric and evolutionary factors in networks and to model the complexity of real networks with comparatively little effort.

Martin Pyka

2014-09-01

302

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

Science.gov (United States)

Computational models of neural networks can be based on a variety of different parameters. These parameters include, for example, the 3d shape of neuron layers, the neurons' spatial projection patterns, spiking dynamics and neurotransmitter systems. While many well-developed approaches are available to model, for example, the spiking dynamics, there is a lack of approaches for modeling the anatomical layout of neurons and their projections. We present a new method, called Parametric Anatomical Modeling (PAM), to fill this gap. PAM can be used to derive network connectivities and conduction delays from anatomical data, such as the position and shape of the neuronal layers and the dendritic and axonal projection patterns. Within the PAM framework, several mapping techniques between layers can account for a large variety of connection properties between pre- and post-synaptic neuron layers. PAM is implemented as a Python tool and integrated in the 3d modeling software Blender. We demonstrate on a 3d model of the hippocampal formation how PAM can help reveal complex properties of the synaptic connectivity and conduction delays, properties that might be relevant to uncover the function of the hippocampus. Based on these analyses, two experimentally testable predictions arose: (i) the number of neurons and the spread of connections is heterogeneously distributed across the main anatomical axes, (ii) the distribution of connection lengths in CA3-CA1 differ qualitatively from those between DG-CA3 and CA3-CA3. Models created by PAM can also serve as an educational tool to visualize the 3d connectivity of brain regions. The low-dimensional, but yet biologically plausible, parameter space renders PAM suitable to analyse allometric and evolutionary factors in networks and to model the complexity of real networks with comparatively little effort. PMID:25309338

Pyka, Martin; Klatt, Sebastian; Cheng, Sen

2014-01-01

303

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

Science.gov (United States)

Computational models of neural networks can be based on a variety of different parameters. These parameters include, for example, the 3d shape of neuron layers, the neurons' spatial projection patterns, spiking dynamics and neurotransmitter systems. While many well-developed approaches are available to model, for example, the spiking dynamics, there is a lack of approaches for modeling the anatomical layout of neurons and their projections. We present a new method, called Parametric Anatomical Modeling (PAM), to fill this gap. PAM can be used to derive network connectivities and conduction delays from anatomical data, such as the position and shape of the neuronal layers and the dendritic and axonal projection patterns. Within the PAM framework, several mapping techniques between layers can account for a large variety of connection properties between pre- and post-synaptic neuron layers. PAM is implemented as a Python tool and integrated in the 3d modeling software Blender. We demonstrate on a 3d model of the hippocampal formation how PAM can help reveal complex properties of the synaptic connectivity and conduction delays, properties that might be relevant to uncover the function of the hippocampus. Based on these analyses, two experimentally testable predictions arose: (i) the number of neurons and the spread of connections is heterogeneously distributed across the main anatomical axes, (ii) the distribution of connection lengths in CA3-CA1 differ qualitatively from those between DG-CA3 and CA3-CA3. Models created by PAM can also serve as an educational tool to visualize the 3d connectivity of brain regions. The low-dimensional, but yet biologically plausible, parameter space renders PAM suitable to analyse allometric and evolutionary factors in networks and to model the complexity of real networks with comparatively little effort.

Pyka, Martin; Klatt, Sebastian; Cheng, Sen

2014-01-01

304

Anatomical modeling of the bronchial tree  

Science.gov (United States)

The bronchial tree is of direct clinical importance in the context of respective diseases, such as chronic obstructive pulmonary disease (COPD). It furthermore constitutes a reference structure for object localization in the lungs and it finally provides access to lung tissue in, e.g., bronchoscope based procedures for diagnosis and therapy. This paper presents a comprehensive anatomical model for the bronchial tree, including statistics of position, relative and absolute orientation, length, and radius of 34 bronchial segments, going beyond previously published results. The model has been built from 16 manually annotated CT scans, covering several branching variants. The model is represented as a centerline/tree structure but can also be converted in a surface representation. Possible model applications are either to anatomically label extracted bronchial trees or to improve the tree extraction itself by identifying missing segments or sub-trees, e.g., if located beyond a bronchial stenosis. Bronchial tree labeling is achieved using a naïve Bayesian classifier based on the segment properties contained in the model in combination with tree matching. The tree matching step makes use of branching variations covered by the model. An evaluation of the model has been performed in a leaveone- out manner. In total, 87% of the branches resulting from preceding airway tree segmentation could be correctly labeled. The individualized model enables the detection of missing branches, allowing a targeted search, e.g., a local rerun of the tree-segmentation segmentation.

Hentschel, Gerrit; Klinder, Tobias; Blaffert, Thomas; Bülow, Thomas; Wiemker, Rafael; Lorenz, Cristian

2010-02-01

305

Anatomic variants at sinonasal CT  

International Nuclear Information System (INIS)

The threefold role of CT scanning in functional endoscopic sinus surgery is providing anatomic definition, determining significant variants, and relating these to current pathology. Significant variants were present in 330 (55%) of a series of 600 patients. These variants were sufficient to cause potential obstruction or to interfere with endoscopic access to the ostiomeatal complex and the frontal recess. Twenty-four percent of patients had more than one variant. This paper demonstrates the major variants that the surgeon encounters and may impair mucociliary drainage. It shows multiple variants in common combinations and also illustrates less common anomalies

306

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

307

Anatomical studies of some medicinal plants of family polygonaceae  

International Nuclear Information System (INIS)

Anatomical studies of the 6 different species of family Polygonaceae viz., Rumex hastatus D. Don, Rumex dentatus Linn, Rumex nepalensis Spreng, Rheum australe D. Don, Polygonum plebejum R. Br and Persicaria maculosa S.F. Gay are presented. The study is based on the presence and absence of epidermis, parenchyma, collenchyma, sclerenchyma, endodermis, pericycle, xylem, phloem, pith, mesophyll cells and stone cells. (author)

308

Morphometric analysis of anatomical relationships of the facial nerve for mastoid surgery.  

Science.gov (United States)

Surgical anatomical relationships of the facial nerve (FN) with several landmarks used in mastoid surgery were studied in temporal bone axial high resolution CT scans of 90 patients (180 ears). The shortest distances between the FN and external auditory canal (EAC), sigmoid sinus (SS), posterior fossa dural plate (PFD), and joint of the bony EAC with the lateral surface of the mastoid (M) were measured. These measurements were also analysed in respect of pneumatization and side differences. On average, it was found that FN-EAC was 2.9 mm, FN-SS was 10.5 mm, FN-PFD was 7.3 mm and FN-M was 15.3 mm. FN-EAC was found to be longer in poorly pneumatized bones whereas other distances were longer in pneumatized bones. FN-M was found to be longer on the right side. PMID:11429065

Aslan, A; Goktan, C; Okumus, M; Tarhan, S; Unlu, H

2001-06-01

309

CT-Angiography–Based Evaluation of the Aortic Annulus for Prosthesis Sizing in Transcatheter Aortic Valve Implantation (TAVI)–Predictive Value and Optimal Thresholds for Major Anatomic Parameters  

Science.gov (United States)

Background/Objectives To evaluate the predictive value of CT-derived measurements of the aortic annulus for prosthesis sizing in transcatheter aortic valve implantation (TAVI) and to calculate optimal cutoff values for the selection of various prosthesis sizes. Methods The local IRB waived approval for this single-center retrospective analysis. Of 441 consecutive TAVI-patients, 90 were excluded (death within 30 days: 13; more than mild aortic regurgitation: 10; other reasons: 67). In the remaining 351 patients, the CoreValve (Medtronic) and the Edwards Sapien XT valve (Edwards Lifesciences) were implanted in 235 and 116 patients. Optimal prosthesis size was determined during TAVI by inflation of a balloon catheter at the aortic annulus. All patients had undergone CT-angiography of the heart or body trunk prior to TAVI. Using these datasets, the diameter of the long and short axis as well as the circumference and the area of the aortic annulus were measured. Multi-Class Receiver-Operator-Curve analyses were used to determine the predictive value of all variables and to define optimal cutoff-values. Results Differences between patients who underwent implantation of the small, medium or large prosthesis were significant for all except the large vs. medium CoreValve (all p’s<0.05). Furthermore, mean diameter, annulus area and circumference had equally high predictive value for prosthesis size for both manufacturers (multi-class AUC’s: 0.80, 0.88, 0.91, 0.88, 0.88, 0.89). Using the calculated optimal cutoff-values, prosthesis size is predicted correctly in 85% of cases. Conclusion CT-based aortic root measurements permit excellent prediction of the prosthesis size considered optimal during TAVI. PMID:25084451

Schwarz, Florian; Lange, Philipp; Zinsser, Dominik; Greif, Martin; Boekstegers, Peter; Schmitz, Christoph; Reiser, Maximilian F.; Kupatt, Christian; Becker, Hans C.

2014-01-01

310

A method based on Monte Carlo simulations and voxelized anatomical atlases to evaluate and correct uncertainties on radiotracer accumulation quantitation in beta microprobe studies in the rat brain  

International Nuclear Information System (INIS)

The ?-microprobe is a simple and versatile technique complementary to small animal positron emission tomography (PET). It relies on local measurements of the concentration of positron-labeled molecules. So far, it has been successfully used in anesthetized rats for pharmacokinetics experiments and for the study of brain energetic metabolism. However, the ability of the technique to provide accurate quantitative measurements using 18F, 11C and 15O tracers is likely to suffer from the contribution of 511 keV gamma rays background to the signal and from the contribution of positrons from brain loci surrounding the locus of interest. The aim of the present paper is to provide a method of evaluating several parameters, which are supposed to affect the quantification of recordings performed in vivo with this methodology. We have developed realistic voxelized phantoms of the rat whole body and brain, and used them as input geometries for Monte Carlo simulations of previous ?-microprobe reports. In the context of realistic experiments (binding of 11C-Raclopride to D2 dopaminergic receptors in the striatum; local glucose metabolic rate measurement with 18F-FDG and H2O15 blood flow measurements in the somatosensory cortex), we have calculated the detection efficiencies and corresponding contribution of 511 keV gammas from peripheral organs accumulation. We confirmed that the 511 keV gammas background does not impair quantification. To evaluate the contribution of positrons from adjacent structures, we have developed ?-Assistant, a program based on a rat brain voxelized atlas and matrices of local detection efficiencies calculated by Monte Carlo simulations for several probe geometries. This program was used to calculate the 'apparent sensitivity' of the probe for each brain structure included in the detection volume. For a given localization of a probe within the brain, this allows us to quantify the different sources of beta signal. Finally, since stereotaxic accuracy is crucial for quantification in most microprobe studies, the influence of stereotaxic positioning error was studied for several realistic experiments in favorable and unfavorable experimental situations (binding of 11C-Raclopride to D2 dopaminergic receptors in the striatum; binding of 18F-MPPF to 5HT1A receptors in the dorsal raphe nucleus)

311

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

312

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 | Language: 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.

313

Digital photography in anatomical pathology  

Directory of Open Access Journals (Sweden)

Full Text Available Digital imaging has made major inroads into the routine practice of anatomical pathology and replaces photographic prints and Kodachromes for reporting and conference purposes. More advanced systems coupled to computers allow greater versatility and speed of turnaround as well as lower costs of incorporating macroscopic and microscopic pictures into pathology reports and publications. Digital images allow transmission to remote sites via the Internet for consultation, quality assurance and educational purposes, and can be stored on and disseminated by CD-ROM. Total slide digitisation is now a reality and will replace glass slides to a large extent. Three-dimensional images of gross specimens can be assembled and posted on websites for interactive educational programmes. There are also applications in research, allowing more objective and automated quantitation of a variety of morphological and immunohistological parameters. Early reports indicate that medical vision systems are a reality and can provide for automated computer-generated histopathological diagnosis and quality assurance.

Leong F

2004-01-01

314

Network models in anatomical systems.  

Science.gov (United States)

Network theory has been extensively used to model the underlying structure of biological processes. From genetics to ecology, network thinking is changing our understanding of complex systems, specifically how their internal structure determines their overall behavior. Concepts such as hubs, scale-free or small-world networks, common in the complexity literature, are now used more and more in sociology, neurosciences, as well as other anthropological fields. Even though the use of network models is nowadays so widely applied, few attempts have been carried out to enrich our understanding in the classical morphological sciences such as in comparative anatomy or physical anthropology. The purpose of this article is to introduce the usage of network tools in morphology; specifically by building anatomical networks, dealing with the most common analyses and problems, and interpreting their outcome. PMID:21911916

Esteve-Altava, Borja; Marugán-Lobón, Jesús; Botella, Héctor; Rasskin-Gutman, Diego

2011-01-01

315

Automated anatomical interpretation of ion distributions in tissue: linking imaging mass spectrometry to curated atlases.  

Science.gov (United States)

Imaging mass spectrometry (IMS) has become a prime tool for studying the distribution of biomolecules in tissue. Although IMS data sets can become very large, computational methods have made it practically feasible to search these experiments for relevant findings. However, these methods lack access to an important source of information that many human interpretations rely upon: anatomical insight. In this work, we address this need by (1) integrating a curated anatomical data source with an empirically acquired IMS data source, establishing an algorithm-accessible link between them and (2) demonstrating the potential of such an IMS-anatomical atlas link by applying it toward automated anatomical interpretation of ion distributions in tissue. The concept is demonstrated in mouse brain tissue, using the Allen Mouse Brain Atlas as the curated anatomical data source that is linked to MALDI-based IMS experiments. We first develop a method to spatially map the anatomical atlas to the IMS data sets using nonrigid registration techniques. Once a mapping is established, a second computational method, called correlation-based querying, gives an elementary demonstration of the link by delivering basic insight into relationships between ion images and anatomical structures. Finally, a third algorithm moves further beyond both registration and correlation by providing automated anatomical interpretation of ion images. This task is approached as an optimization problem that deconstructs ion distributions as combinations of known anatomical structures. We demonstrate that establishing a link between an IMS experiment and an anatomical atlas enables automated anatomical annotation, which can serve as an important accelerator both for human and machine-guided exploration of IMS experiments. PMID:25153352

Verbeeck, Nico; Yang, Junhai; De Moor, Bart; Caprioli, Richard M; Waelkens, Etienne; Van de Plas, Raf

2014-09-16

316

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

317

Anatomical Entity Recognition with a Hierarchical Framework Augmented by External Resources  

Science.gov (United States)

References to anatomical entities in medical records consist not only of explicit references to anatomical locations, but also other diverse types of expressions, such as specific diseases, clinical tests, clinical treatments, which constitute implicit references to anatomical entities. In order to identify these implicit anatomical entities, we propose a hierarchical framework, in which two layers of named entity recognizers (NERs) work in a cooperative manner. Each of the NERs is implemented using the Conditional Random Fields (CRF) model, which use a range of external resources to generate features. We constructed a dictionary of anatomical entity expressions by exploiting four existing resources, i.e., UMLS, MeSH, RadLex and BodyPart3D, and supplemented information from two external knowledge bases, i.e., Wikipedia and WordNet, to improve inference of anatomical entities from implicit expressions. Experiments conducted on 300 discharge summaries showed a micro-averaged performance of 0.8509 Precision, 0.7796 Recall and 0.8137 F1 for explicit anatomical entity recognition, and 0.8695 Precision, 0.6893 Recall and 0.7690 F1 for implicit anatomical entity recognition. The use of the hierarchical framework, which combines the recognition of named entities of various types (diseases, clinical tests, treatments) with information embedded in external knowledge bases, resulted in a 5.08% increment in F1. The resources constructed for this research will be made publicly available. PMID:25343498

Xu, Yan; Hua, Ji; Ni, Zhaoheng; Chen, Qinlang; Fan, Yubo; Ananiadou, Sophia; Chang, Eric I-Chao; Tsujii, Junichi

2014-01-01

318

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

319

PET image reconstruction using information theoretic anatomical priors.  

Science.gov (United States)

We describe a nonparametric framework for incorporating information from co-registered anatomical images into positron emission tomographic (PET) image reconstruction through priors based on information theoretic similarity measures. We compare and evaluate the use of mutual information (MI) and joint entropy (JE) between feature vectors extracted from the anatomical and PET images as priors in PET reconstruction. Scale-space theory provides a framework for the analysis of images at different levels of detail, and we use this approach to define feature vectors that emphasize prominent boundaries in the anatomical and functional images, and attach less importance to detail and noise that is less likely to be correlated in the two images. Through simulations that model the best case scenario of perfect agreement between the anatomical and functional images, and a more realistic situation with a real magnetic resonance image and a PET phantom that has partial volumes and a smooth variation of intensities, we evaluate the performance of MI and JE based priors in comparison to a Gaussian quadratic prior, which does not use any anatomical information. We also apply this method to clinical brain scan data using F(18) Fallypride, a tracer that binds to dopamine receptors and therefore localizes mainly in the striatum. We present an efficient method of computing these priors and their derivatives based on fast Fourier transforms that reduce the complexity of their convolution-like expressions. Our results indicate that while sensitive to initialization and choice of hyperparameters, information theoretic priors can reconstruct images with higher contrast and superior quantitation than quadratic priors. PMID:20851790

Somayajula, Sangeetha; Panagiotou, Christos; Rangarajan, Anand; Li, Quanzheng; Arridge, Simon R; Leahy, Richard M

2011-03-01

320

Use of deformed intensity distributions for on-line modification of image-guided IMRT to account for interfractional anatomic changes  

International Nuclear Information System (INIS)

Purpose: Recent imaging studies have demonstrated that there can be significant changes in anatomy from day to day and over the course of radiotherapy as a result of daily positioning uncertainties and physiologic and clinical factors. There are a number of strategies to minimize such changes, reduce their impact, or correct for them. Measures to date have included improved immobilization of external and internal anatomy or adjustment of positions based on portal or ultrasound images. Perhaps the most accurate way is to use CT image-guided radiotherapy, for which the possibilities range from simple correction of setup based on daily CT images to on-line near real-time intensity modulated radiotherapy (IMRT) replanning. In addition, there are numerous intermediate possibilities. In this paper, we report the development of one such intermediate method that takes into account anatomic changes by deforming the intensity distributions of each beam based on deformations of anatomy as seen in the beam's-eye-view. Methods and materials: The intensity distribution deformations are computed based on anatomy deformations discerned from the changes in the current image relative to a reference image (e.g., the pretreatment CT scan). First, a reference IMRT plan is generated based on the reference CT image. A new CT image is acquired using an in-room CT for every fraction. The anatomic structure contours are obtained for the new image. (For this article, these contours were manuall this article, these contours were manually drawn. When image guided IMRT methods are implemented, anatomic structure contours on subsequent images will likely be obtained with automatic or semiautomatic means. This could be achieved by, for example, first deforming the original CT image to match today's image, and then using the same deformation transformation to map original contours to today's image.) The reference intensity distributions for each beam are then deformed so that the projected geometric relationship within the beam's-eye-view between the anatomy (both target and normal tissues) extracted from the reference image and the reference intensity distribution is the same as (or as close as possible to) the corresponding relationship between anatomy derived from today's image and the newly deformed intensity distributions. To verify whether the dose distributions calculated using the deformed intensity distributions are acceptable for treatment as compared to the original intensity distributions, the deformed intensities are transformed into leaf sequences, which are then used to compute intensity and dose distributions expected to be delivered. The corresponding dose-volume histograms and dose-volume and dose-response indices are also computed. These data are compared with the corresponding data derived (a) from the original treatment plan applied to the original image, (b) from the original treatment plan applied to today's image, and (c) from a new full-fledged IMRT plan designed based on today's image. Results: Depending on the degree of anatomic changes, the use of an IMRT plan designed based on the original planning CT for the treatment of the current fraction could lead to significant differences compared to the intended dose distributions. CT-guided setup compared to the setup based on skin marks or bony landmarks may improve dose distributions somewhat. Replanning IMRT based on the current fraction's image yields the best physically deliverable plan (the 'gold standard'). For the prostate and head-and-neck examples studied as proof of principle, the results of deforming intensities within each beam based on the anatomy seen in the beam's-eye-view are a good approximation of full-fledged replanning compared with other alternatives. Conclusions: Our preliminary results encourage us to believe that deforming intensities taking into account deformation in the anatomy may be a rapid way to produce new treatment plans on-line in near real-time based on daily CT images. The methods we have developed need to be applied to a group of patients for b

 
 
 
 
321

36 CFR 62.4 - Natural landmark designation and recognition process.  

Science.gov (United States)

...area's natural values, integrity, or...official land or tax records, whichever...State the land or tax records are not helpful...purposes of NEPA which impacts the NNL or these...natural landmarks are added to the National Registry...deterioration of the natural values on which...

2010-07-01

322

Landmarks in the Professional and Academic Development of Mid-Career Teacher Educators  

Science.gov (United States)

This paper focuses on the professional and academic development of mid-career teacher educators from two universities in England. The objectives of the study were to analyse and compare the career experiences of teacher educators; in particular, to identify stages of development, landmark events and contextual factors affecting professional…

Griffiths, Vivienne; Thompson, Simon; Hryniewicz, Liz

2014-01-01

323

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

324

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

325

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

326

36 CFR 65.5 - Designation of National Historic Landmarks.  

Science.gov (United States)

...Themes which reflect the broad planning needs of NPS...from official land or tax record, whichever is...any State the land or tax record is not the appropriate...and any comments and, based on the criteria set forth...and any comments and, based on the criteria set...

2010-07-01

327

36 CFR 65.5 - Designation of National Historic Landmarks.  

Science.gov (United States)

...the National Park System,” 1982. (2...which reflect the broad planning needs of...from official land or tax record, whichever...State the land or tax record is not the...any comments and, based on the criteria set...any comments and, based on the criteria...

2010-07-01

328

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

329

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

330

Morphological and anatomical studies of Cyani herba  

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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

331

[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

332

Effects of Instructional Strategies Using Cross Sections on the Recognition of Anatomical Structures in Correlated CT and MR Images  

Science.gov (United States)

This research is an effort to best utilize the interactive anatomical images for instructional purposes based on cognitive load theory. Three studies explored the differential effects of three computer-based instructional strategies that use anatomical cross-sections to enhance the interpretation of radiological images. These strategies include:…

Khalil, Mohammed K.; Paas, Fred; Johnson, Tristan E.; Su, Yung K.; Payer, Andrew F.

2008-01-01

333

Evaluation of soft tissue thicknesses of facial midline landmarks before and after puberty  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction: In recent years, proportions and harmony of orofacial soft tissues have gained great importance in orthodontics. The aim of this research was to evaluate soft tissue thickness changes of facial midline landmarks during growth in both genders.Materials and methods: In this analytical-descriptive study, lateral cephalometric views of ninety-eight 6-18 year-old patients referring to the Orthodontics Department of Khorasegan Azad University were evaluated. The positions of 7 facial midline landmarks, including glabella, soft tissue nasion, soft tissue points A and B, soft tissue pogonion, and superior and inferior labrale, were determined and then the thicknesses of the landmarks were measured. Data was compared between two groups of under and above 12 years of age between males and females using independent t-test (?=0.05.Results: There were no statistically significant differences between the soft tissue thicknesses of both sexes in any of the landmarks except nasion (p value=0.026 and point B (p value=0.043 in the group under 12 years of age. Differences between the soft tissue thicknesses in both sexes over 12 years of age were statistically significant in nasion (p value = 0.043, point A (p value=0.001, and superior labrale (p value<0.001. Differences between soft tissue thicknesses of all the landmarks were statistically significant between the two age groups in males except point B (p value=0.119; however, in females only the thickness of soft tissue nasion (p value=0.105 and superior labrale (p value=0.968 were not statistically significant between the two age groups.Conclusion: Soft tissue thicknesses were almost the same in boys and girls except nasion and point B before puberty. After puberty upper face soft tissue thicknesses, including glabella and point A, were greater in boys compared to girls. However, in both sexes, soft tissue thicknesses of facial midline landmarks increased after 12 years of age. Key words: Soft tissue, Orthodontics, Radiography.

Soosan Sadeghian

2011-01-01

334

Anatomical basis for Wilms tumor surgery  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2009-01-01

335

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

336

A high-resolution anatomical framework of the neonatal mouse brain for managing gene expression data  

Directory of Open Access Journals (Sweden)

Full Text Available This study aims to provide a high-resolution atlas and use it as an anatomical framework to localize the gene expression data for mouse brain on postnatal day 0 (P0. A color Nissl-stained volume with a resolution of 13.3×50×13.3 µm3 was constructed and co-registered to a standard anatomical space defined by an averaged geometry of C57BL/6J P0 mouse brains. A 145 anatomical structures were delineated based on the histological images. Anatomical relationships of delineated structures were established based on the hierarchical relations defined in the atlas of adult mouse brain (MacKenzie-Graham et al., 2004 so the P0 atlas can be related to the database associated with the adult atlas. The co-registered multimodal atlas as well as the original anatomical delineations is available for download at http://www.loni.ucla.edu/Atlases/. The region-specific anatomical framework based on the neonatal atlas allows for the analysis of gene activity within a high-resolution anatomical space at an early developmental stage. We demonstrated the potential application of this framework by incorporating gene expression data generated using in situ hybridization to the atlas space. By normalizing the gene expression patterns revealed by different images, experimental results from separate studies can be compared and summarized in an anatomical context. Co-displaying multiple registered datasets in the atlas space allows for 3D reconstruction of the co-expression patterns of the different genes in the atlas space, hence providing better insight into the relationship between the differentiated distribution pattern of gene products and specific anatomical systems.

JylBoline

2007-11-01

337

Development of a landmark recognition system for the posture measurement of mobile robots  

International Nuclear Information System (INIS)

A landmark recognition system, consisting of retroreflective landmarks, a CCD camera, a strobe unit, an image processing board, and processing software, has been developed to solve the problem of the posture (position and orientation) identification of mobile robots in manufacturing environments. The binary image processing technique instead of gray image technique has been adapted in this system to perform the fast posture measurement of the robots. The experimental results demonstrated real-time measurement capability of this system while maintaining good reliability and reasonable accuracy. A camera calibration technique has been described to reduce the effects of unwanted measurement error sources. The system after camera calibration procedure has demonstrated enhanced performance in terms of error component in posture measurement. (Author)

338

Employing anatomical knowledge in vertebral column labeling  

Science.gov (United States)

The spinal column constitutes the central axis of human torso and is often used by radiologists to reference the location of organs in the chest and abdomen. However, visually identifying and labeling vertebrae is not trivial and can be timeconsuming. This paper presents an approach to automatically label vertebrae based on two pieces of anatomical knowledge: one vertebra has at most two attached ribs, and ribs are attached only to thoracic vertebrae. The spinal column is first extracted by a hybrid method using the watershed algorithm, directed acyclic graph search and a four-part vertebra model. Then curved reformations in sagittal and coronal directions are computed and aggregated intensity profiles along the spinal cord are analyzed to partition the spinal column into vertebrae. After that, candidates for rib bones are detected using features such as location, orientation, shape, size and density. Then a correspondence matrix is established to match ribs and vertebrae. The last vertebra (from thoracic to lumbar) with attached ribs is identified and labeled as T12. The rest of vertebrae are labeled accordingly. The method was tested on 50 CT scans and successfully labeled 48 of them. The two failed cases were mainly due to rudimentary ribs.

Yao, Jianhua; Summers, Ronald M.

2009-02-01

339

Molecular architecture of classical cytological landmarks: Centromeres and telomeres  

Energy Technology Data Exchange (ETDEWEB)

Both the human telomere repeat and the pericentromeric repeat sequence (GGAAT)n were isolated based on evolutionary conservation. Their isolation was based on the premise that chromosomal features as structurally and functionally important as telomeres and centromeres should be highly conserved. Both sequences were isolated by high stringency screening of a human repetitive DNA library with rodent repetitive DNA. The pHuR library (plasmid Human Repeat) used for this project was enriched for repetitive DNA by using a modification of the standard DNA library preparation method. Usually DNA for a library is cut with restriction enzymes, packaged, infected, and the library is screened. A problem with this approach is that many tandem repeats don`t have any (or many) common restriction sites. Therefore, many of the repeat sequences will not be represented in the library because they are not restricted to a viable length for the vector used. To prepare the pHuR library, human DNA was mechanically sheared to a small size. These relatively short DNA fragments were denatured and then renatured to C{sub o}t 50. Theoretically only repetitive DNA sequences should renature under C{sub o}t 50 conditions. The single-stranded regions were digested using S1 nuclease, leaving the double-stranded, renatured repeat sequences.

Meyne, J.

1994-11-01

340

The role of anatomic information in quantifying functional neuroimaging data  

International Nuclear Information System (INIS)

When using modern neuroimaging tools, such as CT, PET, SPECT, MRI and MEG, in brain research and brain diagnostics, there is a common need for including external anatomical information into the interpretation and analysis of data. This information may be used to aid the interpretation of structures in images from low resolution imaging tools. With high resolution tools it can help to identify resolved structures. It can also facilitate the merging of data from different modalities, or from different individuals. The anatomical information is often given as regions of interests (ROIs), which may be manually created from an anatomy rich image or automatically created from a standard template collection or from an atlas data base. Automatic methods will lead to a substantial reduction in bias and in size of the systematic errors. Functional ROIs can correspondingly be derived from functional images (usually PET or SPECT). Different aspects of these processes are discussed in the report. (authors)

 
 
 
 
341

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

342

Groupwise registration by hierarchical anatomical correspondence detection.  

Science.gov (United States)

We present a novel feature-based groupwise registration method to simultaneously warp the subjects towards the common space. Due to the complexity of the groupwise registration, we resort to decoupling it into two easy-to-solve tasks, i.e., alternatively establishing the robust correspondences across different subjects and interpolating the dense deformation fields based on the detected sparse correspondences. Specifically, several novel strategies are proposed in the correspondence detection step. First, attribute vector, instead of intensity only, is used as a morphological signature to guide the anatomical correspondence detection among all subjects. Second, we detect correspondence only on the driving voxels with distinctive attribute vectors for avoiding the ambiguity in detecting correspondences for non-distinctive voxels. Third, soft correspondence assignment (allowing for adaptive detection of multiple correspondences in each subject) is also presented to help establish reliable correspondences across all subjects, which is particularly necessary in the beginning of groupwise registration. Based on the sparse correspondences detected on the driving voxels of each subject, thin-plate splines (TPS) are then used to propagate the correspondences on the driving voxels to the entire brain image for estimating the dense transformation for each subject. By iteratively repeating correspondence detection and dense transformation estimation, all the subjects will be aligned onto a common space simultaneously. Our groupwise registration algorithm has been extensively evaluated by 18 elderly brains, 16 NIREP, and 40 LONI data. In all experiments, our algorithm achieves more robust and accurate registration results, compared to a groupwise registration method and a pairwise registration method, respectively. PMID:20879375

Wu, Guorong; Wang, Qian; Jia, Hongjun; Shen, Dinggang

2010-01-01

343

Gamma camera-mounted anatomical X-ray tomography: technology, system characteristics and first images  

International Nuclear Information System (INIS)

Scintigraphic diagnosis, based on functional image interpretation, becomes more accurate and meaningful when supported by corresponding anatomical data. In order to produce anatomical images that are inherently registered with images of emission computerised tomography acquired with a gamma camera, an X-ray transmission system was mounted on the slip-ring gantry of a GEMS millennium VG gamma camera. The X-ray imaging system is composed of an X-ray tube and a set of detectors located on opposite sides of the gantry rotor that moves around the patient along with the nuclear detectors. A cross-sectional anatomical transmission map is acquired as the system rotates around the patient in a manner similar to a third-generation computerised tomography (CT) system. Following transmission, single-photon emission tomography (SPET) or positron emission tomography (PET) coincidence detection images are acquired and the resultant emission images are thus inherently registered to the anatomical maps. Attenuation correction of the emission images is performed with the same anatomical maps to generate transmission maps. Phantom experiments of system performance and examples of first SPET and coincidence detection patient images are presented. Despite limitations of the system when compared with a state of the art CT scanner, the transmission anatomical maps allow for precise anatomical localisation and for attenuation correction of the emission images. (orig.)

344

Megaliths as land-marks. Chronicle of the territorial role of the megalithic monuments through written sources  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Megalithic monuments have played dijferent roles throughout History. One of them has a spatial function, i.e. as landmarks. The aim of this paper has been to collect and analyse every written reference concerning Galician megaliths operating as landmarks between the 6th and 19th centuries AD. On this basis, the evolution of this social-territorial function of the monuments through time is reconstructed, and an interpretative hypothesis for this phenomenon is proposed. Finally, the importance ...

Martino?n-torres, Marcos

2001-01-01

345

Restoration of the round locomotive depot, a moscow landmark ??????????? ????????? ??????????? — ?????? ????????? ??????????? ????  

Directory of Open Access Journals (Sweden)

Full Text Available Nikolaev railway depot is one of the first locomotive depots in Russia. It is a monument of cultural heritage, and it belongs to a group of buildings of the Leningrad Railroad Station in Moscow. The depot was designed by renowned architects K.A. Ton andR.A. Zhelyazevich in 1951. The depot building is round; it consists of 22 sections. The bearing structures of the building, its columns, arches and vaults are made of masonry. The depot building was remodeled several times, following changes in its intended use. Therefore, the original look of the building has lost its initial splendour. Now its structures are badly damaged, and the bearing capacity of its masonry columns and arches has changed for the worse. Its reconstruction will be accompanied by the restoration of its original exterior. Its reconstruction must be accompanied by the comprehensive monitoring of the stress-strain state of its surviving structures. The renovation must be based on the structural analysis of changes of its properties and damages. Currently, the engineering staff of our university is monitoring the strained state of the building to give advice in the course of its further restoration.????????? ??????? ??????? ?????????? ? ???? ???????? ??????????????? ??????????????? ?????????? ?????? ????????? ???? — ?????? ?? ???????? ?????????? ???????????? ??????????? XIX ?. ??????? ???????????? ??????????? ???????????? ????? ?????? ? ?? ??????????? ??????????? ?????????. ??????????? ???????? ???????????? ?????? ??? ??????????? ??????. ?????????? ???????????? ?? ??????????? ??????? ??????????? ? ??????????? ?????????.

Perunov Aleksandr Sergeevich

2013-05-01

346

Lateral laryngopharyngeal diverticulum: anatomical and videofluoroscopic study  

International Nuclear Information System (INIS)

The aims were to characterize the anatomical region where the lateral laryngopharyngeal protrusion occurs and to define if this protrusion is a normal or a pathological entity. This protrusion was observed on frontal contrasted radiographs as an addition image on the upper portion of the laryngopharynx. We carried out a plane-by-plane qualitative anatomical study through macroscopic and mesoscopic surgical dissection on 12 pieces and analyzed through a videofluoroscopic method on frontal incidence the pharyngeal phase of the swallowing process of 33 patients who had a lateral laryngopharyngeal protrusion. The anatomical study allowed us to identify the morphological characteristics that configure the high portion of the piriform recess as a weak anatomical point. The videofluoroscopic study allowed us to observe the laryngopharyngeal protrusion and its relation to pharyngeal repletion of the contrast medium. All kinds of the observed protrusions could be classified as ''lateral laryngopharyngeal diverticula.'' The lateral diverticula were more frequent in older people. These lateral protrusions can be found on one or both sides, usually with a small volume, without sex or side prevalence. This formation is probably a sign of a pharyngeal transference difficulty associated with a deficient tissue resistance in the weak anatomical point of the high portion of the piriform recess. (orig.)

347

Lateral laryngopharyngeal diverticulum: anatomical and videofluoroscopic study  

Energy Technology Data Exchange (ETDEWEB)

The aims were to characterize the anatomical region where the lateral laryngopharyngeal protrusion occurs and to define if this protrusion is a normal or a pathological entity. This protrusion was observed on frontal contrasted radiographs as an addition image on the upper portion of the laryngopharynx. We carried out a plane-by-plane qualitative anatomical study through macroscopic and mesoscopic surgical dissection on 12 pieces and analyzed through a videofluoroscopic method on frontal incidence the pharyngeal phase of the swallowing process of 33 patients who had a lateral laryngopharyngeal protrusion. The anatomical study allowed us to identify the morphological characteristics that configure the high portion of the piriform recess as a weak anatomical point. The videofluoroscopic study allowed us to observe the laryngopharyngeal protrusion and its relation to pharyngeal repletion of the contrast medium. All kinds of the observed protrusions could be classified as ''lateral laryngopharyngeal diverticula.'' The lateral diverticula were more frequent in older people. These lateral protrusions can be found on one or both sides, usually with a small volume, without sex or side prevalence. This formation is probably a sign of a pharyngeal transference difficulty associated with a deficient tissue resistance in the weak anatomical point of the high portion of the piriform recess. (orig.)

Costa, Milton Melciades Barbosa [Universidade Federal do Rio de Janeiro ICB/CCS/UFRJ, Laboratorio de Motilidade Digestiva e Imagem, S. F1-008, Departamento de Anatomia, Rio de Janeiro (Brazil); Koch, Hilton Augusto [Universidade Federal do Rio de Janeiro ICB/CCS/UFRJ, Departamento de Radiologia, Rio de Janeiro (Brazil)

2005-07-01

348

Anatomic research of suboccipito-retrosigmoidal approach for minimally invasive exposure of facial-acoustic nerve complex utilizing virtual reality skill  

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Full Text Available Objective To discuss microanatomy features of facial-acoustic nerve complex in suboccipito-retrosigmoidal minimally invasive approach based on virtual reality image model. Methods CT and MRI scans were performed to 5 adult cadaver heads, and then, image data was inputted into Vitrea virtual reality system to establish three-dimensional anatomy model of facial-acoustic nerve complex. Suboccipito-retrosigmoidal approach was simulated by selecting osseous landmark points on the calvaria and skull base. Anatomic exposures in surgical trajectory were observed and measured following minimally invasive design. Statistical comparison was launched by paired t test. Results Routes simulating suboccipito-retrosigmoidal approach for exposure of facial-acoustic nerve complex passed under the inferior edge of transverse sinus. Spacial sequence of nerves and vessels in the route was displayed clearly. Vertebral artery and posterior inferior cerebellar artery did not show in the route. Cerebella, lower cranial nerves, anterior inferior cerebellar artery, facial-acoustic nerve complex were exposed successively in route before minimally invasive design. Then, lower cranial nerves pierced the jugular foramen at the site between the jugular bulb and inferior petrosal sinus. Minimally invasive route was higher than that before minimally invasive design and involved cerebella, anterior inferior cerebellar artery and facial-acoustic nerve complex successively. Lower cranial nerves and jugular bulb were not shown in minimally invasive route. Measure and comparative analysis showed that volumes of route (t = 36.331, P = 0.000 and cerebella (t = 16.775, P = 0.000 involved before minimally invasive design were more than that after minimally invasive design with statistically significant difference. Comparison did not show significant differences for the volumes of facial-acoustic nerve complex (t = 1.680, P = 0.127 and anterior inferior cerebellar artery (t = 1.278, P = 0.233 between routes before and after minimally invasive design. Conclusions Minimally invasive routes of suboccipito-retrosigmoidal approach can reduce surgical injury without sacrifice of anatomic exposure for facial-acoustic nerve complex. doi: 10.3969/j.issn.1672-6731.2014.06.008

Ke TANG

2014-06-01

349

3D reconstruction of prostate histology based on quantified tissue cutting and deformation parameters  

Science.gov (United States)

Methods for 3D histology reconstruction from sparse 2D digital histology images depend on knowledge about the positions, orientations, and deformations of tissue slices due to the histology process. This work quantitatively evaluates typical assumptions about the position and orientation of whole-mount prostate histology sections within coarsely sliced tissue blocks and about the deformation of tissue during histological processing and sectioning. 3-5 midgland tissue blocks from each of 7 radical prostatectomy specimens were imaged using magnetic resonance imaging before histology processing. After standard whole-mount paraffin processing and sectioning, the resulting sections were digitised. Homologous anatomic landmarks were identified on 22 midgland histology and MR images. Orientations and depths of sections relative to the front faces of the tissue blocks were measured based on the best-fit plane through the landmarks on the MR images. The mean+/-std section orientation was 1.7+/-1.1° and the mean+/-std depth of the sections was 1.0+/-0.5 mm. Deformation was assessed by using four transformation models (rigid, rigid+scale, affine and thin-plate-spline (TPS)) to align landmarks from histology and MR images, and evaluating each by measuring the target registration error (TRE) using a leave-one-out cross-validation. The rigid transformation model had higher mean TRE (p<0.001) than the other models, and the rigid+scale and affine models had higher mean TRE than the TPS model (p<0.001 and p<0.01 respectively). These results informed the design and development of a method for 3D prostate histology reconstruction based on extrinsic strand-shaped fiducial markers which yielded a 0.7+/-0.4 mm mean+/-std TRE.

Gibson, Eli; Gómez, José A.; Moussa, Madeleine; Crukley, Cathie; Bauman, Glenn; Fenster, Aaron; Ward, Aaron D.

2012-03-01

350