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1

Anatomical landmarks for transnasal endoscopic skull base surgery.  

UK PubMed Central (United Kingdom)

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.

Sandu K; Monnier P; Pasche P

2012-01-01

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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

2011-07-09

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Anatomical landmarks of radical prostatecomy.  

UK PubMed Central (United Kingdom)

INTRODUCTION: In the present study, we review current literature and based on our experience, we present the anatomical landmarks of open and laparoscopic/endoscopic radical prostatectomy. METHODS: A thorough literature search was performed with the Medline database on the anatomy and the nomenclature of the structures surrounding the prostate gland. The correct handling of puboprostatic ligaments, external urethral sphincter, prostatic fascias and neurovascular bundle is necessary for avoiding malfunction of the urogenital system after radical prostatectomy. RESULTS: When evaluating new prostatectomy techniques, we should always take into account both clinical and final oncological outcomes. The present review adds further knowledge to the existing "postprostatectomy anatomical hazard" debate. It emphasizes upon the role of the puboprostatic ligaments and the course of the external urethral sphincter for urinary continence. When performing an intrafascial nerve sparing prostatectomy most urologists tend to approach as close to the prostatic capsula as possible, even though there is no concurrence regarding the nomenclature of the surrounding fascias and the course of the actual neurovascular bundles. After completion of an intrafascial technique the specimen does not contain any periprostatic tissue and thus the detection of pT3a disease is not feasible. This especially becomes problematic if the tumour reaches the resection margin. DISCUSSION: Nerve sparing open and laparoscopic radical prostatectomy should aim in maintaining sexual function, recuperating early continence after surgery, without hindering the final oncological outcome to the procedure. Despite the different approaches for radical prostatectomy the key for better results is the understanding of the anatomy of the bladder neck and the urethra.

Stolzenburg JU; Schwalenberg T; Horn LC; Neuhaus J; Constantinides C; Liatsikos EN

2007-03-01

4

Anatomic Landmarks for the First Dorsal Compartment  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Objective: Knowledge of anatomic landmarks for the first dorsal compartment can assist clinicians with management of de Quervain's disease. The radial styloid, the scaphoid tubercle, and Lister's tubercle can be used as superficial landmarks for the first dorsal compartment. Methods: Thirty-two cada...

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

5

Validation of anatomical landmarks-based registration for image-guided surgery: An in-vitro study.  

UK PubMed Central (United Kingdom)

INTRODUCTION: Perioperative navigation is a recent addition to orthognathic surgery. This study aimed to evaluate the accuracy of anatomical landmarks-based registration. MATERIALS AND METHODS: Eighty-five holes (1.2 mm diameter) were drilled in the surface of a plastic skull model, which was then scanned using a SkyView cone beam computed tomography scanner. DICOM files were imported into BrainLab ENT 3.0.0 to make a surgical plan. Six anatomical points were selected for registration: the infraorbital foramena, the anterior nasal spine, the crown tips of the upper canines, and the mesial contact point of the upper incisors. Each registration was performed five times by two separate observers (10 times total). RESULTS: The mean target registration error (TRE) in the anterior maxillary/zygomatic region was 0.93 ± 0.31 mm (p < 0.001 compared with other anatomical regions). The only statistically significant inter-observer difference of mean TRE was at the zygomatic arch, but was not clinically relevant. CONCLUSION: With six anatomical landmarks used, the mean TRE was clinically acceptable in the maxillary/zygomatic region. This registration technique may be used to access occlusal changes during bimaxillary surgery, but should be used with caution in other anatomical regions of the skull because of the large TRE observed.

Sun Y; Luebbers HT; Agbaje JO; Schepers S; Vrielinck L; Lambrichts I; Politis C

2013-09-01

6

Anatomic landmarks for Basal joint injections.  

UK PubMed Central (United Kingdom)

Objective: Basal joint arthritis is a common cause of pain and disability, particularly in elderly women. Corticosteroid injection with splinting provides a reliable long-term relief for patients with mild arthritis. Proper location of the basal joint with anatomic landmarks can facilitate diagnosis and treatment of basal joint arthritis while avoiding inadvertent injury to local structures. The purpose of this study is to identify bony anatomic landmarks for basal joint injections and aid clinicians in avoiding inadvertent injury to surrounding structures on the radial side of the wrist. Methods: Twenty fresh cadaveric wrists were dissected with the aid of loupe magnification. The distal edge of the radial styloid and the palpable dorsal aspect of the thumb metacarpophalangeal joint were used as bony anatomic landmarks for the identification of the basal joint along a longitudinal vector. Measurements of the distance from our anatomic landmarks to the basal joint space were recorded. The locations of the radial artery and the superficial branch of the radial nerve were noted in relation to the borders of the anatomic snuffbox at the basal joint level. Results: The basal joint of the thumb is located 2.44 ± 0.34 cm distal to the distal edge of the radial styloid, and 4.47 ± 0.29 cm proximal to the metacarpophalangeal joint. At the level of the basal joint, the radial artery is found 0.76 ± 0.12 cm dorsal to the extensor pollicis brevis tendon. The first branch of the superficial branch of the radial nerve is volar to the abductor pollicis longus tendon in 84% of the specimens and courses over the abductor pollicis longus tendon in 16%. Conclusion: The basal joint of the thumb is approximately 2.4 cm distal to the radial styloid and 4.5 cm proximal to the metacarpophalangeal joint. Placement of a needle in the basal joint space immediately dorsal to extensor pollicis brevis tendon while applying longitudinal traction on the thumb is more likely to avoid damage to the radial artery and the superficial branch of the radial nerve.

Hazani R; Engineer NJ; Elston J; Wilhelmi BJ

2012-01-01

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Anatomic landmarks in the sleeve gastrectomy.  

UK PubMed Central (United Kingdom)

BACKGROUND AND OBJECTIVES: The vertical sleeve gastrectomy is a common bariatric procedure. The operation is relatively standard, but there are still variations among surgeons. The two main variations are bougie size and extent of distal resection. Some surgeons will start the gastric resection at 2 cm proximal to the pylorus, whereas others start at 6 cm. Our hypothesis is that there are anatomic landmarks that are constant and can be used to help standardize the procedure. METHODS: Twenty-eight morbidly obese patients undergoing laparoscopic bariatric surgery (gastric bypass or sleeve gastrectomy) had the distance from the pylorus to the second branch of the right gastroepiploic artery on the inferior border of the greater curvature of the stomach measured. Body mass index, height, weight, age, and sex were also analyzed. RESULTS: The study comprised 22 women and 6 men with a mean age of 46.2 years (range, 22-68 years). The mean body mass index was 43.2 kg/m(2) (range, 37.2-62.4 kg/m(2)). The mean distance from the pylorus to the second branch of the right gastroepiploic vessel was 4.52 cm (range, 3.5-5.5 cm). CONCLUSION: The second branch of the right gastroepiploic artery can be used as a constant anatomic landmark. It is found about 4.5 cm from the pylorus. This can be safely used as a landmark for marking the distal extent of resection during a vertical sleeve gastrectomy and obviates the need to formally measure the distance from the pylorus.

Clapp B

2013-01-01

8

Progressive data transmission for anatomical landmark detection in a cloud.  

UK PubMed Central (United Kingdom)

BACKGROUND: In the concept of cloud-computing-based systems, various authorized users have secure access to patient records from a number of care delivery organizations from any location. This creates a growing need for remote visualization, advanced image processing, state-of-the-art image analysis, and computer aided diagnosis. OBJECTIVES: This paper proposes a system of algorithms for automatic detection of anatomical landmarks in 3D volumes in the cloud computing environment. The system addresses the inherent problem of limited bandwidth between a (thin) client, data center, and data analysis server. METHODS: The problem of limited bandwidth is solved by a hierarchical sequential detection algorithm that obtains data by progressively transmitting only image regions required for processing. The client sends a request to detect a set of landmarks for region visualization or further analysis. The algorithm running on the data analysis server obtains a coarse level image from the data center and generates landmark location candidates. The candidates are then used to obtain image neighborhood regions at a finer resolution level for further detection. This way, the landmark locations are hierarchically and sequentially detected and refined. RESULTS: Only image regions surrounding landmark location candidates need to be trans- mitted during detection. Furthermore, the image regions are lossy compressed with JPEG 2000. Together, these properties amount to at least 30 times bandwidth reduction while achieving similar accuracy when compared to an algorithm using the original data. CONCLUSIONS: The hierarchical sequential algorithm with progressive data transmission considerably reduces bandwidth requirements in cloud-based detection systems.

Sofka M; Ralovich K; Zhang J; Zhou SK; Comaniciu D

2012-01-01

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Anatomical landmarks based assessment of intravertebral space level for lumbar puncture is misleading in more than 30%.  

UK PubMed Central (United Kingdom)

BACKGROUND: The anatomical landmark which is used to identify the correct level for lumbar puncture is the line connecting both iliac crests. This crosses the vertebra column at the level of the L4-L5 intervertebral space or L4 vertebra. It can be difficult to determine in a group of orthopaedic patients due to chronic orthopaedic disorders, chronic pain, overweight, or difficulties with positioning for lumbar puncture. The objective of this study was to determine if identification of intervertebral space by a physical exam differs from that of an ultrasound assessment. METHODS: Adult patients scheduled for lower limb surgery under spinal block were enrolled in this study. The intervertebral space suitable for lumbar puncture was determined by physical exam by an anaesthetist in the sitting or lateral position. This was followed by a lumbar ultrasound. Primarily, a transducer was placed in paramedian sagittal view followed by transverse interlaminar view to confirm the identification of the interlaminar spaces. The 'counting-up' approach starting with the L5-1 space was applied. RESULTS: One hundred and twenty two patients (122) were included in this study. Lumbar intervertebral spaces were identified by ultrasound in all cases. There was concordance of intervertebral space identification (between clinical and ultrasound examination) in 78 cases (64%). Mean deviation of inacuracy was one intervertebral space with no statistical difference among cephalad and caudal direction. There were no statistically significant differences fund in terms of demographic data (sex, age, height, weight, or BMI), positioning for lumbar puncture, or intervertebral space chosen for the puncture between the concordant and the nonconcordant identification groups. The only statistically significant difference found was the difference in the years of experience of the anaesthetist performing the clinical assessment and puncture. CONCLUSIONS: The concordance rate between clinical examination and using assessment of intervertebral space identification for lumbar puncture is 64% among patients undergoing lower limb surgery. No special parameters were found which could make an anaesthetist aware that a patient is at greater risk of inadequate intervertebral space level assessment. Spinal ultrasound can reduce the incidence of inappropriate lumbar puncture level in orthopaedic patients.

Duniec L; Nowakowski P; Kosson D; ?azowski T

2013-01-01

10

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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Cardiac Conduction System: Delineation of Anatomic Landmarks With Multidetector CT  

Directory of Open Access Journals (Sweden)

Full Text Available Major components of the cardiac conduction system including the sinoatrial node (SAN), atrioventricular node (AVN), the His Bundle, and the right and left bundle branches are too small to be directly visualized by multidetector CT (MDCT) given the limited spatial resolution of current scanners. However, the related anatomic landmarks and variants of this system a well as the areas with special interest to electrophysiologists can be reliably demonstrated by MDCT. Some of these structures and landmarks include the right SAN artery, right atrial cavotricuspid isthmus, Koch triangle, AVN artery, interatrial muscle bundles, and pulmonary veins. In addition, MDCT has an imperative role in demarcating potential arrhythmogenic structures. The aim of this review will be to assess the extent at which MDCT can outline the described anatomic landmarks and therefore provide crucial information used in clinical practice.

Farhood Saremi; Maria Torrone; Nooshin Yashar

2009-01-01

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

International Nuclear Information System (INIS)

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

2010-01-01

13

The use of anatomical landmarks for percutaneous nephrolithotomy  

Directory of Open Access Journals (Sweden)

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

Esat Kaan Akbay; Burak Turna; Servet Çelik; Emil Mukhtarov; Ahmet Bar?? Altay; Oktay Nazl?

2012-01-01

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Intra-articular hip injection using anatomic surface landmarks.  

UK PubMed Central (United Kingdom)

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

Masoud MA; Said HG

2013-05-01

15

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

The identification of the facial nerve can be difficult in a bloody operative field or by an incision that limits exposure; hence anatomical landmarks and adequate operative exposure can aid such identification and preservation. In this clinico-anatomic study, we examined the stylomastoid artery (SM...

Upile, T; Jerjes, W; Nouraei, SA; Singh, SU; Kafas, P; Sandison, A; Sudhoff, H; Hopper, C

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Landmarks of the sacral hiatus for caudal epidural block: an anatomical study.  

UK PubMed Central (United Kingdom)

BACKGROUND: This study determined the landmarks for caudal epidural block (CEB) after morphometric measurements of the sacral hiatus on dry sacral bones. Anatomical features of the sacral hiatus of clinical importance during CEB, along with distances and angles of use in detecting the apex, were measured. This provides detailed knowledge of the anatomy of the sacral hiatus and practical landmarks. METHODS: Ninety-six dry sacral bones were used. Anatomical measurements were made with a Vernier caliper accurate to 0.1 mm. RESULTS: Two sacral bones were excluded since they had total posterior closure defect. Agenesis of the sacral hiatus was detected in six sacral bones. As the posterior superior iliac spines impose on the superolateral sacral crests of the sacrum, the latter were accepted as forming the base of a triangle. The distance between the two superolateral sacral crests and the distances between the sacral apex and the right and left superolateral sacral crest were 66.5 (SD 53.5), 67.1 (10.0) and 67.5 (9.5) mm respectively, on average. CONCLUSION: The triangle formed between the apex of the sacral hiatus and the superolateral sacral crests was found to have the features of an equilateral triangle. The sacrum and sacral hiatus are variable anatomical structures. However, the equilateral triangle located between the apex of the sacral hiatus and superolateral sacral crests will certainly be of use in determining the location of the sacral hiatus during CEB.

Senoglu N; Senoglu M; Oksuz H; Gumusalan Y; Yuksel KZ; Zencirci B; Ezberci M; Kizilkanat E

2005-11-01

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Anatomical confirmation of the use of radiographic landmarks in medial patellofemoral ligament reconstruction.  

UK PubMed Central (United Kingdom)

BACKGROUND: A recent study has described radiographic landmarks for femoral insertion of the medial patellofemoral ligament. Clinical relevance and application of these landmarks for surgical reconstruction have yet to be determined. HYPOTHESIS: Radiographic landmarks can be used to accurately determine the femoral insertion of the medial patellofemoral ligament in a percutaneous fluoroscopically guided surgical technique. STUDY DESIGN: Descriptive laboratory study. METHODS: The femoral insertion of the medial patellofemoral ligament was estimated using fluoroscopy in 8 fresh-frozen human cadaveric knees. The knees were dissected and the true anatomical medial patellofemoral ligament femoral insertion was identified. Radiographic markers were placed on both the estimated and anatomical medial patellofemoral ligament and a repeat lateral radiograph was performed. Using imaging software, the distance between the true anatomical insertion and the fluoroscopically determined insertion was calculated. Results All 8 points determined by fluoroscopically guided pin placement averaged less than 4 mm from the anatomical insertion. The radiographic landmark method consistently placed the origin on average 2.5 mm anterior and 0.6 mm distal to the anatomical insertion. CONCLUSION: Radiographic landmarks determined by fluoroscopy can be used to accurately reproduce the femoral insertion of the medial patellofemoral ligament in ligament reconstruction. CLINICAL RELEVANCE: Confirming the use of radiographic landmarks to determine the medial patellofemoral ligament femoral insertion may help to increase accuracy and precision in ligament reconstruction and minimize surgical dissection.

Redfern J; Kamath G; Burks R

2010-02-01

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Endoscopic endonasal transpterygoid approaches: anatomical landmarks for planning the surgical corridor.  

UK PubMed Central (United Kingdom)

OBJECTIVES/HYPOTHESIS: Endoscopic endonasal transpterygoid approaches (EETA) use the pneumatization of the sinonasal corridor to control lesions of the middle and posterior skull base. These surgical areas are complex and the required surgical corridors are difficult to predict. AIM: Define anatomical landmarks for the preoperative planning of EETAs. STUDY DESIGN: Anatomical study. METHODS: We reviewed images from high-resolution maxillofacial CT scans with (0.6-mm axial slice acquisition). Cephalometric measurements were obtained using Kodak Carestream Image Software (Rochester, NY). RESULTS: Average distance from midline to the vidian canal was 12.78 mm (range 9.4-15.8 mm). Average horizontal distance from the vidian canal to the foramen rotundum was 5.6 mm (range 2.8-11.5 mm). Average vertical distance from the vidian canal to the foramen rotundum was 6.22 mm (range 4.3-9.3 mm). These landmarks are consequential during the preoperative planning of the surgical corridor. To facilitate communication, we classified EETAs as: A) Partial removal of the pterygoid plates (transposition of temporo-parietal fascia); B) removal of anteromedial aspect of the pterygoid process (lesions involving the lateral recess of the sphenoid sinus); C) involves dissecting the vidian nerve to control the petrous ICA and removing the pterygoid plates base to reach the petrous apex, Meckel's cave, or cavernous sinus; D) variable removal of the pterygoid plates to access the infratemporal fossa; and E) removal of pterygoid process and medial third of the Eustachian tube to expose the nasopharynx. CONCLUSIONS: Our novel classification and landmarks system helps to understand the anatomy of this complex area and to accurately plan the EETA.

Kasemsiri P; Solares CA; Carrau RL; Prosser JD; Prevedello DM; Otto BA; Old M; Kassam AB

2013-04-01

19

Ultrasonographic identification of the anatomical landmarks that define cervical lymph nodes spaces.  

UK PubMed Central (United Kingdom)

The localization of cervical lymph nodes is extremely important in practice for the positive and differential diagnosis as well as the staging of cervical lymphadenopathies. Ultrasonography represents the first line imaging method in the diagnosis of cervical lymphadenopathies due to its excellent resolution and high diagnosis accuracy. The present paper aims to illustrate the ultrasonographic identification of the anatomical landmarks used for the definition of cervical lymphatic spaces. The application of standardized views allows a delineation of clear anatomical landmarks and an accurate localization of the cervical lymph nodes.

Lenghel LM; Baciu? G; Botar-Jid C; Vasilescu D; Bojan A; Dudea SM

2013-03-01

20

Anatomical landmarks to avoid injury to the great auricular nerve during rhytidectomy.  

UK PubMed Central (United Kingdom)

BACKGROUND: An estimated 116 086 facelifts were performed in 2011. Regardless of the technique employed, facial flap elevation carries with it anatomical pitfalls of which any surgeon performing these procedures should be aware. Injury to the great auricular nerve (GAN) is the most common of these injuries, occurring at a rate of 6% to 7%. OBJECTIVES: We report our findings on the location of the GAN on the basis of anatomical landmarks to aid surgeons with planning their surgical approach for safe elevation of rhytidectomy skin flaps in the lateral neck region. METHODS: Sixteen fresh cadaveric heads were dissected under loupe magnification. All specimens were dissected in a 45-degree (facelift) position in which a mid-sternocleidomastoid (SCM) incision was used for exposure. Measurements from the bony mastoid process, bony external auditory canal, external jugular vein, and anterior border of the SCM to the GAN were taken in each cadaver. RESULTS: The GAN follows a consistent course over the mid-body of the SCM before bifurcating into anterior and posterior branches and terminal arborization. Regardless of the length of the SCM, the GAN at its most superficial location was found to be consistently at a ratio of one-third the distance from either the mastoid process or the external auditory canal to the clavicular origin of the SCM. CONCLUSIONS: Knowledge of the anatomy, course, and location of the GAN along the surface of SCM muscle based on anatomic landmarks and distance ratios can facilitate a safer dissection in the lateral neck during rhytidectomy procedures.

Lefkowitz T; Hazani R; Chowdhry S; Elston J; Yaremchuk MJ; Wilhelmi BJ

2013-01-01

 
 
 
 
21

Automated landmark identification for human cortical surface-based registration.  

UK PubMed Central (United Kingdom)

Volume-based registration (VBR) is the predominant method used in human neuroimaging to compensate for individual variability. However, surface-based registration (SBR) techniques have an inherent advantage over VBR because they respect the topology of the convoluted cortical sheet. There is evidence that existing SBR methods indeed confer a registration advantage over affine VBR. Landmark-SBR constrains registration using explicit landmarks to represent corresponding geographical locations on individual and atlas surfaces. The need for manual landmark identification has been an impediment to the widespread adoption of Landmark-SBR. To circumvent this obstacle, we have implemented and evaluated an automated landmark identification (ALI) algorithm for registration to the human PALS-B12 atlas. We compared ALI performance with that from two trained human raters and one expert anatomical rater (ENR). We employed both quantitative and qualitative quality assurance metrics, including a biologically meaningful analysis of hemispheric asymmetry. ALI performed well across all quality assurance tests, indicating that it yields robust and largely accurate results that require only modest manual correction (<10 min per subject). ALI largely circumvents human error and bias and enables high throughput analysis of large neuroimaging datasets for inter-subject registration to an atlas.

Anticevic A; Repovs G; Dierker DL; Harwell JW; Coalson TS; Barch DM; Van Essen DC

2012-02-01

22

The lumbar sympathetic trunk: its visibility and distance to two anatomical landmarks.  

UK PubMed Central (United Kingdom)

OBJECTIVE: The lumbar sympathetic trunk's (LST) distance to two anatomical landmarks, the costal process and medial margin of the psoas muscle, was assessed due to its use as landmarks for lumbar sympathetic blocks: the costal process for fluoroscopic guided techniques and the psoas major for CT- and MRI-guided techniques. Based on the measurements, we evaluate the trunk's visibility in MR and CT images for accurate positioning of the needle. METHODS: A total of 54 cadavers embalmed with Thiel's method were investigated. The LST's distances to the psoas major's medial margin and to the base of the lumbar vertebrae's costal process were measured on the levels L2/3, L3/4 and L4/5. The measurements were compared to MR and CT images of 20 anonymous patients to identify the LST. RESULTS: LST's mean distance to the psoas major was 0.3 mm at L2/3, 3.1 mm at L3/4 and 4.6 mm at L4/5. The mean distance to the costal process was 31 mm at L2/3, 34 mm at L3/4 and 32.6 mm at L4/5. In both MR and CT imaging, a structure could be determined as the LST correlating to the measurements with decreasing possible identification from cephalad to caudad levels. CONCLUSIONS: The costal process is a usable landmark for fluoroscopic guidance and the psoas major for CT- and MRI-guided techniques. The LST is clearly visible in MR and CT images, which gives both techniques a decisive advantage over fluoroscopy concerning the block of the LST due to a visible target.

Feigl GC; Kastner M; Ulz H; Breschan C; Pixner T; Dreu M; Umschaden HW; Likar R

2013-03-01

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

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

Sugawara, Yasushi; Harii, Kiyonori (Tokyo Univ. (Japan). Faculty of Medicine); Hirabayashi, Shinichi

1994-05-01

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Anatomical landmarks for locating the sphenoid ostium during endoscopic endonasal approach: a cadaveric study.  

UK PubMed Central (United Kingdom)

PURPOSE: The sphenoid ostium (SO) provides a natural portal for entering the sphenoid sinus and beyond up to the skull base. It is not always easy to locate the ostium during the endoscopic approach. The present study was designed to establish readily identifiable anatomical landmarks for locating the sphenoid ostium. METHODS: Cadaveric dissection was performed in 30 hemisections of head and neck and various measurements were taken from fixed anatomical landmarks in the nasal cavity to the sphenoid ostium. The size, shape and position of sphenoid ostium were determined in relation to the anterior wall of the sphenoid sinus and the superior turbinate. RESULTS: The mean distance from the supero-lateral angle of the posterior choana to the SO was found to be 21.21 ± 6.02 mm. The mean distance of the SO from the midline was 4.85 ± 2.89 mm. In all the specimens, the SO was situated within 1 cm of the midline. The mean distance between the inferior end of the SO and the postero-inferior edge of the superior turbinate was 8.03 ± 3.52 mm. The SO was present on an average distance of 55.1 ± 3.54 mm from the limen nasi. In 93.3 % of the specimens, the SO was situated between 5 and 6 cm of the inferior end of the limen nasi. The angle between the anterior nasal spine and the SO was found to be remarkably constant. In 93.3 % of the specimens, it was from 25° to 30°. CONCLUSIONS: The sphenoid ostium could be localized medial to the superior turbinate between 1.5 and 3 cm above the supero-lateral angle of the posterior choana, within 1 cm of the midline and within 1 cm of the postero-inferior edge of the superior turbinate.

Gupta T; Aggarwal A; Sahni D

2013-03-01

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

Directory of Open Access Journals (Sweden)

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

Upile Tahwinder; Jerjes Waseem; Nouraei Seyed; Singh Sandeep U; Kafas Panagiotis; Sandison Ann; Sudhoff Holger; Hopper Colin

2009-01-01

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Image-guided surgical planning using anatomical landmarks in the retrosigmoid approach.  

UK PubMed Central (United Kingdom)

OBJECTIVE: The suboccipital lateral or retrosigmoid approach is the main neurosurgical approach to the cerebellopontine angle (CPA). It is mainly used in the treatment of CPA tumors and vascular decompression of cranial nerves. A prospective study using navigation registered with anatomical landmarks in order to identify the transverse and sigmoid sinuses junction (TSSJ) was carried out in a series of 30 retrosigmoid craniotomies. The goal of this study was to determine the accuracy of this navigation technique and to establish the relationship between the location of the asterion and the TSSJ. METHODS: From March through November 2008, 30 patients underwent a retrosigmoid craniotomy for removal of CPA tumors or for surgical treatment of neurovascular syndromes. Magnetic resonance imaging (MRI) T1 sequences with gadolinium (FSPGR with FatSst, 1.5 T GE Signa) and frameless navigation (Vector vision, Brainlab) were used for surgical planning. Registration was performed using six anatomical landmarks. The position of the TSSJ indicated by navigation was the landmark to guide the craniotomy. The location of the asterion was compared with the position of the TSSJ. After craniotomy, the real TSSJ position was compared with the virtual position, as demonstrated by navigation. RESULTS: There were 19 cases of vestibular schwannomas, 5 petroclival meningiomas, 3 trigeminal neuralgias, 1 angioblastoma, 1 epidermoid cyst and 1 hemifacial spasm. In all cases, navigation enabled the location of the TSSJ and the emissary vein, with an accuracy flaw below 2 mm. The asterion was located directly over the TSSJ in only seven cases. One patient had a laceration of the sigmoid sinus during the craniotomy. CONCLUSIONS: Navigation using anatomical landmarks for registration is a reliable method in the localization of the TSSJ for retrosigmoid craniotomies and thereby avoiding unnecessary sinus exposure. In addition, the method proved to be fast and accurate. The asterion was found to be a less accurate landmark for the localization of the TSSJ using navigation.

da Silva EB Jr; Leal AG; Milano JB; da Silva LF Jr; Clemente RS; Ramina R

2010-05-01

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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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A New Anatomical and Surgical Landmark in Internal Abdominal Oblique Muscle Fat Triangle  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: To determine the anatomical landmark within the internal oblique muscle. Materials and Methods: In a prospective study, the abdominal wall was examined for internal oblique muscle land marks in 900 patients undergoing laparatomy. Results: There was a fat line at anterior superior iliac spine level to access the underlying layers and then to the abdominal cavity. Conclusion: A fat triangle within the internal oblique muscle provides a suitable region of surgical incision at the lower part of the abdominal wall.

Kazem Madaen; Behrooz Niknafs

2012-01-01

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Intercostobrachial nerves as a novel anatomic landmark for dividing the axillary space in lymph node dissection.  

UK PubMed Central (United Kingdom)

Purpose. Our aim was to assess the feasibility of using the intercostobrachial nerves (ICBNs) as a possible new anatomic landmark for axillaries lymph node dissection in breast cancer patients. Background Data Summary. The preservation of ICBN is now an accepted procedure in this type of dissection; however, it could be improved further to reduce the number of postoperative complications. The axillary space is divided into lower and upper parts by the ICBN-a thorough investigation of the metastasis patterns in lymph nodes found in this area could supply new information leading to such improvements. Methods. Seventy-two breast cancer patients, all about to undergo lymph node dissection and with sentinel lymph nodes identified, were included in this trial. The lymph nodes were collected in two groups, from lower and upper axillary spaces, relative to the intercostobrachial nerves. The first group was further subdivided into sentinel (SLN) and nonsentinel (non-SLN) nodes. All lymph nodes were tested to detect macro- and micrometastasis. Results. All the sentinel lymph nodes were found under the intercostobrachial nerves; more than 10 lymph nodes were located in that space. Moreover, when lymph nodes macrometastasize or micrometastasize above the intercostobrachial nerves, we also observe metastasis-positive nodes under the nerves; when the lower group nodes show no metastasis, the upper group is also metastasis free. Conclusions. Our results show that the intercostobrachial nerves are good candidates for a new anatomic landmark to be used in lymph node dissection procedure.

Li J; Zhang Y; Zhang W; Jia S; Gu X; Ma Y; Li D

2013-01-01

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Subthalamic nucleus deep brain stimulation for Parkinson's disease: magnetic resonance imaging targeting using visible anatomical landmarks.  

UK PubMed Central (United Kingdom)

BACKGROUND: The aim of the present study was to validate a magnetic resonance imaging (MRI) visual procedure to target the subthalamic nucleus (STN) based on surrounding anatomical landmarks. METHODS: 31 consecutive bilaterally implanted parkinsonian patients were included in this study. After identification of the anterior commissure (AC), posterior commissure (PC) and midcommissural point on a three-dimensional T1-weighted sequence, inversion recovery (IR) T2-weighted coronal slices were performed orthogonal to the AC-PC line. On the slice showing the anterior pole of the red nucleus (RN), the target was placed in the inferolateral portion of the subthalamic zone, limited superiorly by the thalamus, laterally by the internal capsule, inferiorly by the substantia nigra and medially by the midline. The distribution of the targets was analyzed in the AC-PC referential. RESULTS: The mean target coordinates were as follows: anteroposterior (AP) = -2.54 mm (+/-1.37 mm), lateral (LAT) = 12.03 mm (+/-0.91 mm) and vertical (VERT) = -6.10 mm (+/-1.52 mm) for the right side, and AP = -2.65 mm (+/-1.36 mm), LAT = -11.97 mm (+/-1.30 mm) and VERT = -5.89 mm (+/-1.52 mm) for the left side. They projected in the inferior portion of the STN on the Schaltenbrand and Wahren atlas [Stuttgart, Thieme, 1977]. CONCLUSION: Identification of the anterior pole of the RN and the subthalamic zone on coronal IR T2-weighted MRI performed orthogonal to the AC-PC line provides a precise visual procedure to target the STN.

Pollo C; Meuli R; Maeder P; Vingerhoets F; Ghika J; Villemure JG

2003-01-01

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Vision-Based Navigation Using Natural Landmarks  

UK PubMed Central (United Kingdom)

MYNORCA is a vision-based navigation systemfor mobile robots, designed principally foroperation in indoor environments. The systemuses vision for detecting obstacles and locatingnatural landmarks. In addition, it is able tosolve navigation problems in which the robot'sinitial location is completely unknown. In thispaper, we present an overview of MYNORCA,describe its implementation and present someexperimental results.1 IntroductionMYNORCA is a vision-based navigation system for mobilerobots, designed principally for operation in indoorenvironments, such as office buildings. MYNORCA dividesthe overall navigation problem into two parts: localand global navigation. Local navigation is defined asthe immediate problem of detecting and avoiding obstacles,whilst global navigation is defined as the problem ofreaching distant goals. This division of responsibilitieshas a double benefit: global navigation can be treated asa fairly abstract planning problem, since ...

Andrew Howard; Les Kitchen

32

Landmark-based elastic registration using approximating thin-plate splines.  

UK PubMed Central (United Kingdom)

We consider elastic image registration based on a set of corresponding anatomical point landmarks and approximating thin-plate splines. This approach is an extension of the original interpolating thin-plate spline approach and allows to take into account landmark localization errors. The extension is important for clinical applications since landmark extraction is always prone to error. Our approach is based on a minimizing functional and can cope with isotropic as well as anisotropic landmark errors. In particular, in the latter case it is possible to include different types of landmarks, e.g., unique point landmarks as well as arbitrary edge points. Also, the scheme is general with respect to the image dimension and the order of smoothness of the underlying functional. Optimal affine transformations as well as interpolating thin-plate splines are special cases of this scheme. To localize landmarks we use a semi-automatic approach which is based on three-dimensional (3-D) differential operators. Experimental results are presented for two-dimensional as well as 3-D tomographic images of the human brain.

Rohr K; Stiehl HS; Sprengel R; Buzug TM; Weese J; Kuhn MH

2001-06-01

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A model-based, semi-global segmentation approach for automatic 3-D point landmark localization in neuroimages.  

UK PubMed Central (United Kingdom)

The existing differential approaches for localization of 3-D anatomic point landmarks in 3-D images are sensitive to noise and usually extract numerous spurious landmarks. The parametric model-based approaches are not practically usable for localization of landmarks that can not be modeled by simple parametric forms. Some dedicated methods using anatomic knowledge to identify particular landmarks are not general enough to cope with other landmarks. In this paper, we propose a model-based, semi-global segmentation approach to automatically localize 3-D point landmarks in neuroimages. To localize a landmark, the semi-global segmentation (meaning the segmentation of a part of the studied structure in a certain neighborhood of the landmark) is first achieved by an active surface model, and then the landmark is localized by analyzing the segmented part only. The joint use of global model-to-image registration, semi-global structure registration, active surface-based segmentation, and point-anchored surface registration makes our method robust to noise and shape variation. To evaluate the method, we apply it to the localization of ventricular landmarks including curvature extrema, centerline intersections, and terminal points. Experiments with 48 clinical and 18 simulated magnetic resonance (MR) volumetric images show that the proposed approach is able to localize these landmarks with an average accuracy of 1 mm (i.e., at the level of image resolution). We also illustrate the use of the proposed approach to cortical landmark identification and discuss its potential applications ranging from computer-aided radiology and surgery to atlas registration with scans.

Liu J; Gao W; Huang S; Nowinski WL

2008-08-01

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Development of a novel constellation based landmark detection algorithm  

Science.gov (United States)

Anatomical landmarks such as the anterior commissure (AC) and posterior commissure (PC) are commonly used by researchers for co-registration of images. In this paper, we present a novel, automated approach for landmark detection that combines morphometric constraining and statistical shape models to provide accurate estimation of landmark points. This method is made robust to large rotations in initial head orientation by extracting extra information of the eye centers using a radial Hough transform and exploiting the centroid of head mass (CM) using a novel estimation approach. To evaluate the effectiveness of this method, the algorithm is trained on a set of 20 images with manually selected landmarks, and a test dataset is used to compare the automatically detected against the manually detected landmark locations of the AC, PC, midbrain-pons junction (MPJ), and fourth ventricle notch (VN4). The results show that the proposed method is accurate as the average error between the automatically and manually labeled landmark points is less than 1 mm. Also, the algorithm is highly robust as it was successfully run on a large dataset that included different kinds of images with various orientation, spacing, and origin.

Ghayoor, Ali; Vaidya, Jatin G.; Johnson, Hans J.

2013-03-01

35

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-11-15

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Accuracy of a transformation method to estimate muscle attachments based on three bony landmarks.  

UK PubMed Central (United Kingdom)

In this work, the accuracy of a transformation method to estimate muscle attachments based on three bony landmarks was assessed. A concept of mathematical error was introduced and applied to a data-set of 17 muscles' attachment lines from the shoulders of seven cadavers. Within the muscles' attachment lines from the studied data-set, mathematical error and anatomical variability average percentage values were 37.3 and 62.7%, respectively, for the scapula, and 54.4 and 45.6%, respectively, for the humerus. To reduce mathematical error in the transformation method presented, the plane formed by the three landmarks of the segment corresponding to the scaled muscles should neither be too close to the origin of the global coordinate system, nor too far away from muscle attachment locations to be transformed. The procedure outlined in this work allows the researcher to analyse the anatomical variability within a data-set.

Matias R; Andrade C; Veloso AP

2011-01-01

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Anatomical landmarks for point-matching registration in image-guided neurosurgery.  

UK PubMed Central (United Kingdom)

BACKGROUND: Accurate patient to image registration is the core for successful image-guided neurosurgery. While skin adhesive markers (SMs) are widely used in point-matching registration, a proper implementation of anatomical landmarks (ALs) may overcome the inconvenience brought by the use of SMs. METHODS: Using nine ALs, a set of three configurations of different combinations of them is proposed. These configurations are defined according to the required positioning of the patient's head during surgery and the resulting distribution of the expected target registration error (TRE). These configurations were first evaluated by simulation experiment using the data of 20 patients from two hospitals, and then testing the applicability of them in eight real clinical surgeries of neuronavigation. RESULTS: The results of the simulation experiment showed that, by incorporating a fiducial registration error (FRE) of 3.5 mm measured in the clinical setting, the expected TRE in the whole skull was less than 2.5 mm, and the expected TRE in the whole brain was less than 1.75 mm when using all the nine ALs. A small TRE could also be achieved in the corresponding surgical field by using the other three configurations with less ALs. In the clinical experiment, the FLE ranges in the image and the patient space were 1.4-3.6 mm and 1.6-5.5 mm, respectively. The measured TRE and FRE were 3.1?±?0.75 mm and 3.5?±?0.17 mm, respectively. CONCLUSIONS: The AL configurations proposed in this investigation provide sufficient registration accuracy and can help to avoid the disadvantages of SMs if used clinically. Copyright © 2013 John Wiley & Sons, Ltd.

Omara AI; Wang M; Fan Y; Song Z

2013-06-01

38

Anatomical landmarks of maxillary bifurcated first premolars and their influence on periodontal diagnosis and treatment.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To assess the anatomical landmarks of the roots of bifurcated maxillary first premolars and study their effect on the diagnosis and management of periodontal disease. METHODS: One hundred sixty-five maxillary first premolars were selected. The frequency of single-, two-rooted, and three-rooted premolars was assessed, but only the dual-rooted were used for the purpose of this study. For each tooth, the following measurements were obtained using a micrometer caliper: buccal and palatal root length, mesial and distal root trunk length, crown length, and width of the furcation entrance. The types of root trunk were classified according to the ratio of root trunk height to root length into types A, B and C. Root trunk types A, B and C are defined as root trunks involving the cervical third or less, up to half of the length of the root, or greater than the apical half of the root, respectively. The presence of any root grooves and concavities, as well as bifurational ridges, was assessed. The crown to root ratio was calculated. RESULTS: Of the 165 maxillary first premolar teeth retrieved, 100 (60.6%) were two-rooted, 62 (37.57%) were single-rooted, and three (1.81%) were triple-rooted. Type A root trunks comprised only 7% of the examined teeth, while types B and C had more or less comparable results (46% and 47% respectively). Type B was more common in distal root trunks while type C was dominant in mesial root trunks. Bifurcation ridges were observed in 37% of the teeth; the mean root trunk length was greater in teeth with bifurcation ridges than in teeth without (7.41 mm vs. 5.96 mm). Root grooves and concavities were found in 96% of the mesial aspects of the root, and in 57% of the palatal aspect of the buccal root. The mean width of the furcation entrance was 0.89 +/- 0.19 mm (range 0.39-1.28). The average crown to root ratio was 0.69:1. CONCLUSION: Awareness of root surface anatomical variations may help the practitioner when assessing the diagnosis, treatment plan and prognosis of periodontally involved two-rooted maxillary premolars.

Dababneh R; Rodan R

2013-01-01

39

Medial arcuate ligament: a new anatomic landmark facilitates the location of the renal artery in retroperitoneal laparoscopic renal surgery.  

UK PubMed Central (United Kingdom)

PURPOSE: The purpose of this study was to introduce a new method for locating the renal artery during retroperitoneal laparoscopic renal surgery. PATIENTS AND METHODS: The medial arcuate ligament (MAL) is a tendinous arch in the fascia under the diaphragm that arches across the psoas major muscle and is attached medially to the side of the first or the second lumbar vertebra. The renal artery arises at the level of the intervertebral disc between the L1 and L2 vertebrae. We evaluate the role of the MAL that serves as an anatomic landmark for locating the renal artery during retroperitoneal laparoscopic renal surgery. RESULTS: There is a reproducible consistent anatomic relationship between MAL and the renal artery in 210 cases of retroperitoneal laparoscopic renal surgery. Two main types of the MAL, the "narrow arch" and the "fascial band" types, can be observed. CONCLUSION: MAL can serve as an accurate and reproducible anatomic landmark for the identification of the renal artery during retroperitoneal laparoscopic renal surgery.

Cai W; Li HZ; Zhang X; Song Y; Ma X; Dong J; Chen W; Chen GF; Xu Y; Lu JS; Wang BJ; Shi TP

2013-01-01

40

Direct and continuous localization of anatomical landmarks for image-guided orthognathic surgery.  

UK PubMed Central (United Kingdom)

OBJECTIVE: The accuracy and consistency of a new image-guided method for orthognathic surgery using direct and continuous landmark localization was compared with that of a conventional method. STUDY DESIGN: Maxillary and mandibular dental casts mounted on an articulator were used as a surgery phantom. We planned six types of surgeries including translations and rotations. The sequential positions of the landmarks determined before surgery could be traced and the difference between planned and actual positions of the landmarks could be visualized during surgery. The final deviation errors were determined with and without applying the pointing instrument to the landmarks. RESULTS: The mean RMS accuracy of 0.47 ± 0.22 mm by direct localization was significantly higher than that of 1.06 ± 0.49 mm by the manual localization. There were no significant differences in accuracies for surgeries using the direct localization method. CONCLUSION: The direct and continuous localization method showed higher accuracy and consistency than conventional manual localization in all phantom surgeries.

Kim SH; Kim DS; Huh KH; Lee SS; Heo MS; Choi SC; Hwang SJ; Yi WJ

2013-10-01

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

Scientific Electronic Library Online (English)

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

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

2005-06-01

42

Intensity-based elastic registration incorporating anisotropic landmark errors and rotational information.  

UK PubMed Central (United Kingdom)

PURPOSE: Thin-plate splines (TPS) represent an effective tool for estimating the deformation that warps one set of landmarks to another based on the physical equivalent of thin metal sheets. In the original formulation, data used to estimate the deformation field are restricted to landmark locations only and thus does not allow to incorporate information about the rotation of the image around the landmark. It furthermore assumes that landmark positions are known exactly which is not the case in real world applications. These localization inaccuracies are propagated to the entire deformation field as each landmark has a global influence. We propose to use a TPS approximation method that incorporates anisotropic landmark errors and rotational information and integrate it into a hierarchical elastic registration framework (HERA). The improvement of the registration performance has been evaluated. METHODS: The proposed TPS approximation scheme integrates anisotropic landmark errors with rotational information of the landmarks. The anisotropic landmark errors are represented by their covariance matrices estimated directly from the image data as a minimal stochastic localization error, i.e. the Cramér-Rao bound. The rotational attribute of each landmark is characterized by an additional angular landmark, thus doubling the number of landmarks in the TPS model. This allows the TPS approximation to better cope up with local deformations. RESULTS: We integrated the proposed TPS approach into the HERA registration framework and applied it to register 161 image pairs from a digital mammogram database. Experiments showed that the mean squared error using the proposed TPS approximation was superior to pure TPS interpolation. On artificially deformed breast images HERA, with the proposed TPS approximation, performed significantly better than the state-of-the-art registration method presented by Rueckert. CONCLUSION: The TPS approximation approach proposed in this publication allows to incorporate anisotropic landmark errors as well as rotational information. The integration of the method into an intensity-based hierarchical non-rigid registration framework is straightforward and improved the registration quality significantly.

Serifovi?-Trbali? A; Demirovi? D; Prljaca N; Szekely G; Cattin PC

2009-09-01

43

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

CERN Multimedia

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

44

Confirmation of needle placement within the piriformis muscle of a cadaveric specimen using anatomic landmarks and fluoroscopic guidance.  

Science.gov (United States)

Of patients presenting to pain clinics, complaints are of low back or buttock pain with or without radicular leg symptoms is one of the most common. Piriformis syndrome may be a contributor in up to 8% of these patients. The mainstay of treatment is conservative management with physical therapy, anti-inflammatory medications, muscle relaxants, and correction of biomechanical abnormalities. However, in recalcitrant cases, a piriformis injection of anesthetic and/or corticosteroids may be considered. Because of its small size, proximity to neurovascular structures, and deep location, the piriformis muscle is often injected with the use of commuted tomography (CT), magnetic resonance imaging (MRI), ultrasound (US), fluoroscopy, electrical stimulators, or electromyography (EMG). Numerous techniques have been proposed using one or a combination of the above modalities. However, application of these techniques is limited by unavailability of CT, MRI, and EMG equipment as well as a paucity of trained physicians in US-guided procedures in many pain treatment centers throughout the United States. Fluoroscopy, however, is more widely available in this setting. This study utilized a cadaveric specimen to confirm proper needle placement for piriformis or peri-sciatic injection utilizing the previously documented landmarks for fluoroscopic guidance as described by Betts. An anteroposterior of the pelvis with inclusion of the acetabular region of the hip and the inferior aspect of the sacroiliac joint was obtained. The most superior-lateral aspect of the acetabulum and the inferior aspect of the sacroiliac joint were identified. A marker was placed one-third of the distance from the acetabular location to the inferior sacroiliac joint, indicating the target location. A 22-gauge, 3.5-inch spinal needle was directed through the gluteal muscles to the target location using intermittent fluoroscopic guidance. The posterior ileum was contacted and the needle was withdrawn 1 -2 mm. This approach found the needle within the piriformis muscle belly 2 -3 cm lateral to sciatic nerve. The present study was the first study, to our knowledge, that has confirmed the intramuscular position of the needle within the piriformis muscle of a cadaveric specimen using these anatomic landmarks and fluoroscopic guidance. PMID:18523503

Gonzalez, Peter; Pepper, Michelle; Sullivan, William; Akuthota, Venu

45

A game-theoretic framework for landmark-based image segmentation.  

UK PubMed Central (United Kingdom)

A novel game-theoretic framework for landmark-based image segmentation is presented. Landmark detection is formulated as a game, in which landmarks are players, landmark candidate points are strategies, and likelihoods that candidate points represent landmarks are payoffs, determined according to the similarity of image intensities and spatial relationships between the candidate points in the target image and their corresponding landmarks in images from the training set. The solution of the formulated game-theoretic problem is the equilibrium of candidate points that represent landmarks in the target image and is obtained by a novel iterative scheme that solves the segmentation problem in polynomial time. The object boundaries are finally extracted by applying dynamic programming to the optimal path searching problem between the obtained adjacent landmarks. The performance of the proposed framework was evaluated for segmentation of lung fields from chest radiographs and heart ventricles from cardiac magnetic resonance cross sections. The comparison to other landmark-based segmentation techniques shows that the results obtained by the proposed game-theoretic framework are highly accurate and precise in terms of mean boundary distance and area overlap. Moreover, the framework overcomes several shortcomings of the existing techniques, such as sensitivity to initialization and convergence to local optima.

Ibragimov B; Likar B; Pernus F; Vrtovec T

2012-09-01

46

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

Directory of Open Access Journals (Sweden)

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

T ahmine Razi; Ali r eza Sighari deljavan

2013-01-01

47

The reproducibility of a kinematically-derived axis of the knee versus digitized anatomical landmarks using a knee navigation system.  

Science.gov (United States)

Component position is critical to longevity of knee arthroplasties. Femoral component rotation is typically referenced from the transepicondylar axis (TEA), the anterior-posterior (AP) axis or the posterior condylar axis. Other studies have shown high variability in locating the TEA while proposing digitization of other landmarks such as the AP axis as a less-variable reference. This study uses a navigation system to compare the reproducibility of computing a kinematically-derived, navigated knee axis (NKA) to digitizing the TEA and AP axis. Twelve knees from unembalmed cadavers were tested. Four arthroplasty surgeons digitized the femoral epicondyles and the AP axis direction as well as flexed and extended the knee repeatedly to allow for NKA determination. The variance of the NKA axis determined under neutral loading conditions was smaller than the variance of the TEA axis when the kinematics were measured in the closed surgical condition (P<0.001). However, varus, valgus, and internal loading of the leg increased the variability of the NKA. Distraction of the leg during knee flexion and extension preserved the low variability of the NKA. In conclusion, a kinematically-derived NKA under neutral or distraction loading is more reproducible than the TEA and AP axis determined by digitization. PMID:19662117

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

2008-09-10

48

Craniofacial osseous landmark determination from stereo computer tomography reconstructions.  

UK PubMed Central (United Kingdom)

The accurate and reproducible determination of the three dimensional (3D) co-ordinate positions of anatomical landmarks from computer tomography (CT) images has been limited even though potentially the data have been available for several years. This paper describes a method of acquisition of osseous landmark positions using an off-line computing technique based on multiple stereo images of 3D CT reconstructions. The use of stereo pairs greatly enhances the consistent identification of osseous landmarks. Further, the technique is of particular value where access to the CT scanner is restricted due to heavy clinical demand and separate high quality graphics facilities are unavailable. Osseous landmark position data were determined for dried skulls and patients with craniofacial conditions. Accuracies of the order 1.7mm (median) were obtained. These results encourage the use of the technique for acquisition of landmark positions for the study of the craniofacial complex in three dimensions.

Abbott AH; Netherway DJ; David DJ; Brown T

1990-09-01

49

Craniofacial osseous landmark determination from stereo computer tomography reconstructions.  

Science.gov (United States)

The accurate and reproducible determination of the three dimensional (3D) co-ordinate positions of anatomical landmarks from computer tomography (CT) images has been limited even though potentially the data have been available for several years. This paper describes a method of acquisition of osseous landmark positions using an off-line computing technique based on multiple stereo images of 3D CT reconstructions. The use of stereo pairs greatly enhances the consistent identification of osseous landmarks. Further, the technique is of particular value where access to the CT scanner is restricted due to heavy clinical demand and separate high quality graphics facilities are unavailable. Osseous landmark position data were determined for dried skulls and patients with craniofacial conditions. Accuracies of the order 1.7mm (median) were obtained. These results encourage the use of the technique for acquisition of landmark positions for the study of the craniofacial complex in three dimensions. PMID:2260813

Abbott, A H; Netherway, D J; David, D J; Brown, T

1990-09-01

50

Within-compound associations explain potentiation and failure to overshadow learning based on geometry by discrete landmarks.  

UK PubMed Central (United Kingdom)

In three experiments, rats were trained to locate a submerged platform in one of the base corners of a triangular arena above each of which was suspended one of two distinctive landmarks. In Experiment 1, it was established that these landmarks differed in their salience by the differential control they gained over behavior after training in compound with geometric cues. In Experiment 2, it was shown that locating the platform beneath the less salient landmark potentiated learning based on geometry compared with control rats for which landmarks provided ambiguous information about the location of the platform. The presence of the more salient landmark above the platform for another group of animals appeared to have no effect on learning based on geometry. Experiment 3 established that these landmark and geometry cues entered into within-compound associations during compound training. We argue that these within-compound associations can account for the potentiation seen in Experiment 2, as well as previous failures to demonstrate overshadowing of geometric cues. We also suggest that these within-compound associations need not be of different magnitudes, despite the different effects of each of the landmarks on learning based on geometry seen in Experiment 2. Instead, within-compound associations appear to mitigate the overshadowing effects that traditional theories of associative learning would predict.

Austen JM; Kosaki Y; McGregor A

2013-07-01

51

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

International Nuclear Information System (INIS)

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

2010-01-01

52

Anatomic Consideration of the C1 Laminar Arch for Lateral Mass Screw Fixation via C1 Lateral Lamina : A Landmark between the Lateral and Posterior Lamina of the C1.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To clarify the landmark for deciding the entry point for C1 lateral mass screws via the posterior arch by using 3-dimensional (3D) computed images. METHODS: Resnick insisted that the C1 posterior arch could be divided into pure posterior and lateral lamina (C1 pedicle). Authors studied where this transition point (TP) is located between the posterior lamina and the C1 pedicle and how it can be recognized. The 3D computed images of 86 cadaver C1s (M : F=45 : 41) were used in this study. RESULTS: The superior ridge of the C1 posterior arch had 2 types of orientation. One was in the vertical direction in the C1 posterior lamina and the other was in the horizontal direction in the C1 pedicle. The TP was located at the border between the 2 areas, the same site as the posterior end of the groove of the vertebral artery. On posterior-anterior projection, the posterior arch was sharpened abruptly at TP. We were unable to identify the TP in 6.4% of specimens due to complete or partial osseous bridges. A total of 93.8% of the TP were located between the most enlarged point of the spinal canal and the medial wall of the vertebral artery. CONCLUSION: The anatomic entry zone of C1 lateral laminar screws was clarified and identified based on the TP by using preoperative 3D computed images.

Kim JH; Kwak DS; Han SH; Cho SM; You SH; Kim MK

2013-07-01

53

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

Scientific Electronic Library Online (English)

Full Text Available 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 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 ob (more) jetivos 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 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 (more) 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

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

2006-09-01

54

A combinatorial method for 3D landmark-based morphometry: application to the study of coronal craniosynostosis.  

UK PubMed Central (United Kingdom)

We present a new method to analyze, classify and characterize 3D landmark-based shapes. It is based on a framework provided by oriented matroid theory, that is on a combinatorial encoding of convexity properties. We apply this method to a set of skull shapes presenting various types of coronal craniosynostosis.

Gioan E; Sol K; Subsol G

2012-01-01

55

Landmark detection and coupled patch registration for cardiac motion tracking  

Science.gov (United States)

Increasing attention has been focused on the estimation of the deformation of the endocardium to aid the diagnosis of cardiac malfunction. Landmark tracking can provide sparse, anatomically relevant constraints to help establish correspondences between images being tracked or registered. However, landmarks on the endocardium are often characterized by ambiguous appearance in cardiac MR images which makes the extraction and tracking of these landmarks problematic. In this paper we propose an automatic framework to select and track a sparse set of distinctive landmarks in the presence of relatively large deformations in order to capture the endocardial motion in cardiac MR sequences. To achieve this a sparse set of the landmarks is identified using an entropy-based approach. In particular we use singular value decomposition (SVD) to reduce the search space and localize the landmarks with relatively large deformation across the cardiac cycle. The tracking of the sparse set of landmarks is performed simultaneously by optimizing a two-stage Markov Random Field (MRF) model. The tracking result is further used to initialize registration based dense motion tracking. We have applied this framework to extract a set of landmarks at the endocardial border of the left ventricle in MR image sequences from 51 subjects. Although the left ventricle undergoes a number of different deformations, we show how the radial, longitudinal motion and twisting of the endocardial surface can be captured by the proposed approach. Our experiments demonstrate that motion tracking using sparse landmarks can outperform conventional motion tracking by a substantial amount, with improvements in terms of tracking accuracy of 20:8% and 19:4% respectively.

Wang, Haiyan; Shi, Wenzhe; Zhuang, Xiahai; Wu, Xianliang; Tung, Kai-Pin; Ourselin, Sebastien; Edwards, Philip; Rueckert, Daniel

2013-03-01

56

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2006-02-15

57

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

UK PubMed Central (United Kingdom)

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

Donner R; Menze BH; Bischof H; Langs G

2013-03-01

58

Automatic identification of the reference system based on the fourth ventricular landmarks in T1-weighted MR images.  

UK PubMed Central (United Kingdom)

RATIONALE AND OBJECTIVES: The reference system based on the fourth ventricular landmarks (including the fastigial point and ventricular floor plane) is used in medical image analysis of the brain stem. The objective of this study was to develop a rapid, robust, and accurate method for the automatic identification of this reference system on T1-weighted magnetic resonance images. MATERIALS AND METHODS: The fully automated method developed in this study consisted of four stages: preprocessing of the data set, expectation-maximization algorithm-based extraction of the fourth ventricle in the region of interest, a coarse-to-fine strategy for identifying the fastigial point, and localization of the base point. The method was evaluated on 27 Brain Web data sets qualitatively and 18 Internet Brain Segmentation Repository data sets and 30 clinical scans quantitatively. RESULTS: The results of qualitative evaluation indicated that the method was robust to rotation, landmark variation, noise, and inhomogeneity. The results of quantitative evaluation indicated that the method was able to identify the reference system with an accuracy of 0.7 +/- 0.2 mm for the fastigial point and 1.1 +/- 0.3 mm for the base point. It took <6 seconds for the method to identify the related landmarks on a personal computer with an Intel Core 2 6300 processor and 2 GB of random-access memory. CONCLUSION: The proposed method for the automatic identification of the reference system based on the fourth ventricular landmarks was shown to be rapid, robust, and accurate. The method has potentially utility in image registration and computer-aided surgery.

Fu Y; Gao W; Chen X; Zhu M; Shen W; Wang S

2010-01-01

59

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

This report describes the piloting mechanisms employed by honey bees during their final approach to a goal. Conceptually applying a bottom-up approach, we systematically varied the position, number and appearance landmarks associated with a rewarded target location within a large, homogenous flight ...

Fry, S N; Wehner, R

60

A Practical Subspace Approach To Landmarking  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 implemen...

Gert Beumer; Raymond Veldhuis

 
 
 
 
61

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

Directory of Open Access Journals (Sweden)

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; Sergey Anishenko; Dmitry Shaposhnikov; Lubov Podlachikova; Stephen Batty; John Clark

2007-01-01

62

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

International Nuclear Information System (INIS)

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

2001-09-01

63

[Method for segmenting medical image based on anatomical model].  

UK PubMed Central (United Kingdom)

OBJECTIVE: To improve the automatization and reliability of medical image segmentation. METHOD: An anatomical model was built and used to guide the low-level segmentation process. The system architecture was made up of an anatomical model, image processing routines and an inference engine, the interaction of which are governed by a blackboard. RESULT: The result of application of the segmentation for chest CT image was satisfactory and needs less operator intensive. CONCLUSION: This method improves automatization and reliability of the medical image segmentation. Because of the good expansibility, it may serve as a template for knowledge-based processing of medical image.

Yang XQ; Li B; Wei SM

2005-02-01

64

Characterization of Anatomical Shape Based on Random Walk Hitting Times  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents an implicit shape representation for describing anatomical shapes with high inter-patient variability based on the expected boundary hitting time of a random walk, which happens to be the solution to the Poisson equation. The main contribution of this paper is to test the validit...

Vesom, Grace; Cahill, Nathan; Gorelick, Lena; Noble, Alison

65

Multiobjective optimization framework for landmark measurement error correction in three-dimensional cephalometric tomography.  

UK PubMed Central (United Kingdom)

The purpose of this study is to minimize errors that occur when using a four vs six landmark superimpositioning method in the cranial base to define the co-ordinate system. Cone beam CT volumetric data from ten patients were used for this study. Co-ordinate system transformations were performed. A co-ordinate system was constructed using two planes defined by four anatomical landmarks located by an orthodontist. A second co-ordinate system was constructed using four anatomical landmarks that are corrected using a numerical optimization algorithm for any landmark location operator error using information from six landmarks. The optimization algorithm minimizes the relative distance and angle between the known fixed points in the two images to find the correction. Measurement errors and co-ordinates in all axes were obtained for each co-ordinate system. Significant improvement is observed after using the landmark correction algorithm to position the final co-ordinate system. The errors found in a previous study are significantly reduced. Errors found were between 1 mm and 2 mm. When analysing real patient data, it was found that the 6-point correction algorithm reduced errors between images and increased intrapoint reliability. A novel method of optimizing the overlay of three-dimensional images using a 6-point correction algorithm was introduced and examined. This method demonstrated greater reliability and reproducibility than the previous 4-point correction algorithm.

DeCesare A; Secanell M; Lagravère MO; Carey J

2013-01-01

66

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 curveof 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

67

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

68

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

Science.gov (United States)

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

69

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

UK PubMed Central (United Kingdom)

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.

Volkau I; Puspitasari F; Ng TT; Bhanu Prakash KN; Gupta V; Nowinski WL

2012-03-01

70

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

UK PubMed Central (United Kingdom)

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

Lisch W; Pitz S; Geerling G

2013-06-01

71

Flexible modeling for anatomically-based cardiac conduction system construction.  

UK PubMed Central (United Kingdom)

We present a method to automatically deploy the peripheral section of the cardiac conduction system in ventricles. The method encodes anatomical information thorough rules that ensure that Purkinje network structures generated are realistic and comparable to those observed in ex-vivo studies. The core methodology is based in non-deterministic production rules that are parameterized by means of statistical functions. Input parameters allow the construction of a great diversity of Purkinje structures that could be incorporated in fine element ventricular models to perform electrophysiology simulations. Resulting Purkinje trees show good geometrical approximations of Purkinje core network and bundles when compared to histological diagrams and do not require user interaction. Simulations carried out with these models result in activation sequences remarkably similar to micro-electrode electrical mapping studies.

Romero D; Zimmerman V; Sebastian R; Frangi AF

2010-01-01

72

PCR-based landmark unique gene (PLUG) markers effectively assign homoeologous wheat genes to A, B and D genomes  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background EST-PCR markers normally represent specific products from target genes, and are therefore effective tools for genetic analysis. However, because wheat is an allohexaploid plant, PCR products derived from homoeologous genes are often simultaneously amplified. Such products may be easier to differentiate if they include intron sequences, which are more polymorphic than exon sequences. However, genomic sequence data for wheat are limited; therefore it is difficult to predict the location of introns. By using the similarities in gene structures between rice and wheat, we developed a system called PLUG (PCR-based Landmark Unique Gene) to design primers so that PCR products include intron sequences. We then investigated whether products amplified using such primers could serve as markers able to distinguish multiple products derived from homoeologous genes. Results The PLUG system consists of the following steps: (1) Single-copy rice genes (Landmark Unique Gene loci; LUGs) exhibiting high degrees of homology to wheat UniGene sequences are extracted; (2) Alignment analysis is carried out using the LUGs and wheat UniGene sequences to predict exon-exon junctions, and LUGs which can be used to design wheat primers flanking introns (TaEST-LUGs) are extracted; and (3) Primers are designed in an interactive manner. From a total of 4,312 TaEST-LUGs, 24 loci were randomly selected and used to design primers. With all of these primer sets, we obtained specific, intron-containing products from the target genes. These markers were assigned to chromosomes using wheat nullisomic-tetrasomic lines. By PCR-RFLP analysis using agarose gel electrophoresis, 19 of the 24 markers were located on at least one chromosome. Conclusion In the development of wheat EST-PCR markers capable of efficiently sorting products derived from homoeologous genes, it is important to design primers able to amplify products that include intron sequences with insertion/deletion polymorphisms. Using the PLUG system, wheat EST sequences that can be used for marker development are selected based on comparative genomics with rice, and then primer sets flanking intron sequences are prepared in an interactive, semi-automatic manner. Hence, the PLUG system is an effective tool for large-scale marker development.

Ishikawa Goro; Yonemaru Junichi; Saito Mika; Nakamura Toshiki

2007-01-01

73

Computerized Three-Dimmensional Craniofacial Reconstruction from Skulls Based on Landmarks.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Human identification from a skull is a critical process in legal and forensic medicine, specially when no other means are available. Traditional clay-based methods attempt to generate the human face, in order to identify the corresponding person. However, these reconstructions lack of objectivity an...

Carnero Pascual, Leticia; Lastres Redondo, Carmen; Rios Sanchez, Belen; Garrido Garrido, David; Santamaria Galdon, Maria Asuncion

74

Landmarks in Hybrid Planning  

Directory of Open Access Journals (Sweden)

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

Mohamed Elkawkagy; Heba Elbeh

2013-01-01

75

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

International Nuclear Information System (INIS)

[en] 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.

2013-01-01

76

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

2010-01-01

77

Acetabular orientation: anatomical and functional measurement.  

UK PubMed Central (United Kingdom)

PURPOSE: Acetabular orientation is important to consider in hip joint pathology and treatment. This study aims to describe the functional orientation of the acetabulum as a representative measure of force transmitted through the hip joint generated from bone density mapping and compare it to landmark-based anatomical orientation measures. METHODS: CT scans of 38 non-pathologic individuals were analyzed. Functional orientation was computed as the density-weighted average of the acetabular surface normals based on surface density maps. Two anatomical measures were also used to describe the orientation of each acetabulum: the normal to the acetabular rim plane and the abduction angle based on AP pelvic "Radiographs" generated from the CT data. RESULTS: The average functional and anatomic abduction and anteversion angles ranged from 32°-58° and 22°-31°, respectively, with significant side-to-side correlation in individual patients for the majority of measures. Functional acetabular orientation was weakly correlated only with the rim plane measure. Native acetabular abduction in the 3D anatomic and functional methods was significantly shallower than the 2D "Radiographic" measure. The vector generated to describe functional acetabular orientation was found to be more vertically and posteriorly oriented than the anatomic measures. CONCLUSIONS: Functional acetabular orientation, reflecting the calculated directionality of the subchondral bone density, yields a more posterior and vertical measure of acetabular orientation as compared to the direction of load transmission suggested by the anatomic methods.

Lubovsky O; Wright D; Hardisty M; Kiss A; Kreder H; Whyne C

2012-03-01

78

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.

2010-11-21

79

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

Science.gov (United States)

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.

Chen, Hsin-Chen; Lin, Chii-Jeng; Wu, Chia-Hsing; Wang, Chien-Kuo; Sun, Yung-Nien

2010-11-01

80

First Steps toward Location of Landmarks on X-Ray Images  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We address the problem of locating some anatomical bone structures on lateral cranial X-ray images. These structures are landmarks used in orthodontic therapy. The main problem in this pattern recognition application is that the landmarks are difficult to distinguish on images even for the human exp...

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

 
 
 
 
81

Landmark-referenced voxel-based analysis of diffusion tensor images of the brainstem white matter tracts: application in patients with middle cerebral artery stroke  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Although DTI can provide detailed information about white matter anatomy, it is not yet straightforward enough to quantify the anatomical information it visualizes. In this study, we developed and tested a new tool to perform brain normalization and voxel-based analysis of DTI data. For the normaliz...

Zhang, W; Lin, X; Zhang, J; Luft, A; Hanley, D F; van Zijl, P; Miller, M I; Younes, L; Mori, S

82

Landmark TAL CB CBS  

UK PubMed Central (United Kingdom)

d.3.0]Figure 5. Isolated cerebellum.Table 3. Landmark locations in all subjects.(mean [s.d.] reported in mm)Landmark TAL CB CBSAC-PC Distance 23.0 [fixed] 27.1 [1.1] 27.1 [1.0]Obex-PC distance 54.4 [3.7] 53.4 [3.0] 54.0 [fixed]AC localization fixed 2.2 [0.7] 2.1 [0.7]Obex localization 5.2 [2.6] 2.3 [1.9] fixedV4 apex localization 3.9 [2.1] 2.9 [1.5] 2.4 [1.5]Lingula localization 2.8 [1.2] 2.1 [0.9] 2.0 [0.9]Primary fissure 3.5 [1.5] 3.0 [1.6] 2.6 [1.6]Horizontal fissure 4.4 [2.1] 4.7 [1.8] 4.5 [1.9]Preculminate fissure 3.1 [1.9] 2.4 [1.3] 2.1 [1.3]Prepyramidal fissure 4.0 [1.8] 3.3 [2.0] 3.0 [1.9]Secondary fissure 4.1 [1.9] 3.1 [1.8] 2.5 [1.7]Yaw angle: 0.4 [s.d. 2.6] Roll angle: 2.4 [s.d. 2.8]Use of Cerebellar Landmarks To Define a Coordinate System and an Isolation StrategyKelly Rehm , David Rottenberg , Kirt Schaper , J

83

Looking for landmarks in medial orbital trauma surgery.  

Science.gov (United States)

Knowledge of the precise location of anatomical landmarks such as the anterior (AEC) and posterior ethmoid (PEC) canals facilitates medial orbital wall surgery and is of major importance for the protection of the orbital nerve. The aim of this study was to identify these anatomical structures in 100 consecutive CT scans and measure the distance between them. The authors investigated whether a predictable symmetry existed between the left and right side. The AEC was not identified unilaterally in one patient, the PEC was not identified unilaterally in six patients and not bilaterally in one patient. An additional PEC was found unilaterally in 12 and bilaterally in five patients. If an anatomical structure was found bilaterally, the authors obtained a strong Pearson's correlation between the sides (r=0.798-0.903, pAEC as reliable surgical landmarks in medial orbital surgery. PMID:23287107

Lethaus, B; Weigl, S; Kloss-Brandstätter, A; Kloss, F R; Kessler, P; Hölzle, F; Bangard, C

2013-01-01

84

Unsupervised Connectivity-Based Thresholding Segmentation of Midsagittal Brain MR Images  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper, we propose an algorithm for automated segmentation of midsagittal brain MR images. First, we apply thresholding to obtain binary images. From the binary images, we locate some landmarks. Based on the landmarks and anatomical information, we preprocess the binary images, which substant...

Lee, C.; Huh, S.; Ketter, T.A.; Unser, M.

85

Breast Augmentation With Anatomic Implants: A Method Based on the Breast Implantation Base.  

UK PubMed Central (United Kingdom)

Currently, aesthetic and reconstructive surgery of the breast should be considered in terms of contouring, and hence in terms of dimensions. Based on experience performing more than 5,000 breast augmentations with highly cohesive anatomic implants, the authors explore the aesthetic anatomy of the (augmented) breast and explain the importance of the breast implantation base (BIB), the aesthetic proportions of the lower breast pole, and the patient's somatotype in the implant selection for a natural-appearing breast augmentation. A method is described for transferring all these concepts and proportions to the preoperative marking of the individual patient. LEVEL OF EVIDENCE V: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Martin Del Yerro JL; Vegas MR; Sanz I; Moreno E; Fernandez V; Puga S; Vecino MG; Biggs TM

2013-09-01

86

Opening base wedge osteotomies in hallux valgus correction: are anatomic plates the answer?  

Science.gov (United States)

This article reintroduces the opening base wedge osteotomy in the treatment of a hallux valgus deformity; moreover, the article identifies the prior pitfalls of the procedure and how these complications can be avoided with modern anatomic plates. These plates provide a stable construct with predictable results. PMID:23827489

Stover, Brian S

2013-05-23

87

Opening base wedge osteotomies in hallux valgus correction: are anatomic plates the answer?  

UK PubMed Central (United Kingdom)

This article reintroduces the opening base wedge osteotomy in the treatment of a hallux valgus deformity; moreover, the article identifies the prior pitfalls of the procedure and how these complications can be avoided with modern anatomic plates. These plates provide a stable construct with predictable results.

Stover BS

2013-07-01

88

Accuracy of computerized automatic identification of cephalometric landmarks by a designed software.  

UK PubMed Central (United Kingdom)

OBJECTIVES: The purpose of this study was to design software for localization of cephalometric landmarks and to evaluate its accuracy in finding landmarks. METHODS: 40 digital cephalometric radiographs were randomly selected. 16 landmarks which were important in most cephalometric analyses were chosen to be identified. Three expert orthodontists manually identified landmarks twice. The mean of two measurements of each landmark was defined as the baseline landmark. The computer was then able to compare the automatic system's estimate of a landmark with the baseline landmark. The software was designed using Delphi and Matlab programming languages. The techniques were template matching, edge enhancement and some accessory techniques. RESULTS: The total mean error between manually identified and automatically identified landmarks was 2.59 mm. 12.5% of landmarks had mean errors less than 1 mm. 43.75% of landmarks had mean errors less than 2 mm. The mean errors of all landmarks except the anterior nasal spine were less than 4 mm. CONCLUSIONS: This software had significant accuracy for localization of cephalometric landmarks and could be used in future applications. It seems that the accuracy obtained with the software which was developed in this study is better than previous automated systems that have used model-based and knowledge-based approaches.

Shahidi Sh; Shahidi S; Oshagh M; Gozin F; Salehi P; Danaei SM

2013-01-01

89

The landmark citation method: analysis of a citation pattern as a collection assessment method.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The landmark citation method is a new collection assessment method based on the citation record of a single landmark article. This citation record is developed by identifying sources which cite the landmark article. A bibliography, extracted from the citation record, is then used to complete an asse...

Soehner, C B; Wray, S T; Richards, D T

90

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; Dayou Liu; Yongming Yang

2011-01-01

91

Accuracy of surface landmark identification for cannula cricothyroidotomy.  

UK PubMed Central (United Kingdom)

Cannula cricothyroidotomy is recommended for emergency transtracheal ventilation by all current airway guidelines. Success with this technique depends on the accurate and rapid identification of percutaneous anatomical landmarks. Six healthy subjects underwent neck ultrasound to delineate the borders of the cricothyroid membrane. The midline and bisecting transverse planes through the membrane were marked with an invisible ink pen which could be revealed with an ultraviolet light. Eighteen anaesthetists were then invited to mark an entry point for cricothyroid membrane puncture. Only 32 (30%) attempts by anaesthetists accurately marked the skin area over the cricothyroid membrane. Of these only 11 (10%) marked over the centre point of the membrane. Entry point accuracy was not significantly affected by subjects' weight, height, body mass index, neck circumference or cricothyroid dimensions. Consultant and registrar anaesthetists were significantly more accurate than senior house officers at correctly identifying the cricothyroid membrane. Accuracy of percutaneously identifying the cricothyroid membrane was poor. Ultrasound may assist in identifying anatomical landmarks for cricothyroidotomy.

Elliott DS; Baker PA; Scott MR; Birch CW; Thompson JM

2010-09-01

92

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; Mark Anthony J. Torres; Cesar G. Demayo

2012-01-01

93

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 2min, 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

2013-08-02

94

Anatomical basis of lumboscopy.  

UK PubMed Central (United Kingdom)

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.

Yiou R; Delmas V; Chopin D; Abbou CC

2001-06-01

95

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; Saman K. Halgamuge

2006-01-01

96

An image processing system for locating craniofacial landmarks  

Energy Technology Data Exchange (ETDEWEB)

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

Cardillo, J.; Sid-Ahmed, M.A. (Univ. of Windsor, Ontario (Canada). Dept. of Electrical Engineering)

1994-06-01

97

[Digital inlaid design based on anatomical characteristics and preliminary implementation of its program].  

UK PubMed Central (United Kingdom)

OBJECTIVE: To explore the technical guideline of inlays computer aided design (CAD) for further development, to test the feasibility of processing for the design results of the technical guideline, and to assist co-operation with automatic inlay CAD software development. METHODS: On the basis of point cloud data of right mandibular first molar of standard crown, we established the coordinate system,the landmarks and lines and the characteristic curves. A dental cast of right mandibular first molar MOD-inlay of an individual normal occlusion was scanned. The following objects were digitized: prepared tooth, neighbor teeth and intercuspal bite record. On the basis of parametric standard crown established in the research, using Surfacer 11.0, we achieved the reconstruction of MOD-inlay by extracting margin line, constructing tissue surface, constructing outer surface and occlusal grinding, then the design result was processed and try-in on the cast. We also developed automatic inlay CAD software based on the guideline of inlay CAD. RESULTS: The guideline of inlay CAD was established, the design results were processed and an automatic inlay CAD software was developed on basis of Surfacer 11.0. CONCLUSION: It is a feasible method to establish technical guideline of inlay based on reverse engineering technology and process its design result, and a automatic inlay CAD software could be developed based on the technical guideline.

Song Y; Sun Yc; Wang Y; Han Jy; Lv Pj

2011-02-01

98

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.

2006-01-01

99

Anatomic considerations for central venous cannulation.  

UK PubMed Central (United Kingdom)

Central venous cannulation is a commonly performed procedure which facilitates resuscitation, nutritional support, and long-term vascular access. Mechanical complications most often occur during insertion and are intimately related to the anatomic relationship of the central veins. Working knowledge of surface and deep anatomy minimizes complications. Use of surface anatomic landmarks to orient the deep course of cannulating needle tracts appropriately comprises the crux of complication avoidance. The authors describe use of surface landmarks to facilitate safe placement of internal jugular, subclavian, and femoral venous catheters. The role of real-time sonography as a safety-enhancing adjunct is reviewed.

Bannon MP; Heller SF; Rivera M

2011-01-01

100

Anatomic considerations for central venous cannulation.  

Science.gov (United States)

Central venous cannulation is a commonly performed procedure which facilitates resuscitation, nutritional support, and long-term vascular access. Mechanical complications most often occur during insertion and are intimately related to the anatomic relationship of the central veins. Working knowledge of surface and deep anatomy minimizes complications. Use of surface anatomic landmarks to orient the deep course of cannulating needle tracts appropriately comprises the crux of complication avoidance. The authors describe use of surface landmarks to facilitate safe placement of internal jugular, subclavian, and femoral venous catheters. The role of real-time sonography as a safety-enhancing adjunct is reviewed. PMID:22312225

Bannon, Michael P; Heller, Stephanie F; Rivera, Mariela

2011-04-13

 
 
 
 
101

Recurrent laryngeal nerve landmarks revisited.  

UK PubMed Central (United Kingdom)

BACKGROUND: The aim of this work was to evaluate, to prove their reliability, the different surgical landmarks previously proposed as a mean to locate the recurrent laryngeal nerve (RLN). METHODS: The necks of 143 (68 male and 76 female) human adult embalmed cadavers were examined. RLN origin and length and its relationship to different landmarks were recorded and results compared with those previously reported. Statistical comparisons were performed using the chi-square test (significance, p ? .05). RESULTS: Mostly, RLN is located anterior to the tracheoesophageal sulcus (41.6%), posterior to the inferior thyroid artery (35.8%), lateral to Berry's ligament (88.1%), below the inferior rim of the inferior constrictor muscle (90.4%), and entering the larynx before its terminal division (54.6%). CONCLUSIONS: The position of the RLN in relation to those structures classically considered as landmarks is highly variable. The most reliable relationships are those with Berry's ligament or the inferior constrictor muscle.

Asgharpour E; Maranillo E; Sañudo J; Pascual-Font A; Rodriguez-Niedenführ M; Valderrama FJ; Viejo F; Parkin IG; Vázquez T

2012-09-01

102

Looking for landmarks in medial orbital trauma surgery.  

UK PubMed Central (United Kingdom)

Knowledge of the precise location of anatomical landmarks such as the anterior (AEC) and posterior ethmoid (PEC) canals facilitates medial orbital wall surgery and is of major importance for the protection of the orbital nerve. The aim of this study was to identify these anatomical structures in 100 consecutive CT scans and measure the distance between them. The authors investigated whether a predictable symmetry existed between the left and right side. The AEC was not identified unilaterally in one patient, the PEC was not identified unilaterally in six patients and not bilaterally in one patient. An additional PEC was found unilaterally in 12 and bilaterally in five patients. If an anatomical structure was found bilaterally, the authors obtained a strong Pearson's correlation between the sides (r=0.798-0.903, p<0.001). An anatomical variation was found in nearly every fourth patient. The authors think that these data call into question the use of the PEC and AEC as reliable surgical landmarks in medial orbital surgery.

Lethaus B; Weigl S; Kloss-Brandstätter A; Kloss FR; Kessler P; Hölzle F; Bangard C

2013-02-01

103

Errors in landmarking and the evaluation of the accuracy of traditional and 3D anthropometry.  

UK PubMed Central (United Kingdom)

Body dimensions are based on landmarks of the body, but the magnitude of error in landmark determination is not well known. Therefore, a study was performed in which 40 subjects were marked five times in total by one highly skilled marker and a novice marker. Immediately after marking, a skilled measurer determined 34 body dimensions that were based on the mark locations. Intra- and inter-observer errors in landmarking of 35 landmarks, as well as those in 34 body dimensions were quantified. The error in landmarking was defined as the distance between two marks made on the same landmark by the same marker (intra-observer error) or by two different markers (inter-observer error). To make the first mark invisible when the second mark was made, the first mark was made using an invisible ink pen under black light. Landmarks with large intra-observer errors also had large inter-observer errors. Errors in body dimensions were smaller than landmarking errors in 23 measurements, which suggested that the magnitude of landmarking error would be underestimated from errors in body dimensions. In 15 body dimensions, measurements based on marks made by two different markers were not comparable according to the ISO 20685 criterion. Examination of body dimensions and landmarks with large inter-observer errors suggested that reducing inter-observer landmarking errors was necessary to reduce inter-observer measurement errors, and that a possible solution was to explicitly define landmarks with large errors in more detail so that anthropometrists can pinpoint them on the skin. Quantitative data on the intra- and inter-observer landmarking errors in the present study may be useful as a reference when evaluating and comparing the performance of software for calculating landmark locations for 3D anthropometry.

Kouchi M; Mochimaru M

2011-03-01

104

Galeal flap based on superficial temporal vessels for oral cavity and pharynx reconstruction: an anatomical study  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english PURPOSE: Despite the advances in microvascular free tissue transfer for intraoral reconstruction, this surgery is not recommended for all patients. In specific cases, the pedicled temporoparietal galeal flap may be an option for reconstructive procedures in the head and neck regions. The objective of this paper is to present the anatomical aspects of a galeal flap based on the superficial temporal vessels and to test its potential for reconstructing diverse sites of the o (more) ral cavity and pharynx. METHODS: We performed 40 dissections on 34 fresh adult cadavers. The flap vascular anatomy was studied by injecting latex into the superficial temporal vessels. A standardized square-shape flap measuring 10 x 10 cm², pedicled on the superficial temporal vessels, was raised. Oral cavity and oropharynx reconstruction simulations were performed after flap transposition into the mouth by passing it under the zygomatic arch. Hypopharyngeal reconstruction was tested by transposing the flap to the neck under the facial nerve. RESULTS: After latex injection, a rich vascular network over the temporoparietal galea was observed directly from the superficial temporal artery, and a well-vascularized flap based on this vessel was raised. In the reconstruction simulations, the flap was shown to be suitable for the coverage of hypothetical defects in most oral cavity and pharyngeal sites, mainly the retromolar trigone, tonsil area, and buccal mucosa. CONCLUSIONS: A galeal flap based on the superficial temporal vessels presents favorable anatomical characteristics for oral cavity and pharyngeal reconstruction.

Pinto, Fabio; Magalhães, Roberto; Durazzo, Marcelo; Brandão, Lenine; Rodrigues Jr., Aldo Junqueira

2008-01-01

105

Galeal flap based on superficial temporal vessels for oral cavity and pharynx reconstruction: an anatomical study  

Directory of Open Access Journals (Sweden)

Full Text Available PURPOSE: Despite the advances in microvascular free tissue transfer for intraoral reconstruction, this surgery is not recommended for all patients. In specific cases, the pedicled temporoparietal galeal flap may be an option for reconstructive procedures in the head and neck regions. The objective of this paper is to present the anatomical aspects of a galeal flap based on the superficial temporal vessels and to test its potential for reconstructing diverse sites of the oral cavity and pharynx. METHODS: We performed 40 dissections on 34 fresh adult cadavers. The flap vascular anatomy was studied by injecting latex into the superficial temporal vessels. A standardized square-shape flap measuring 10 x 10 cm², pedicled on the superficial temporal vessels, was raised. Oral cavity and oropharynx reconstruction simulations were performed after flap transposition into the mouth by passing it under the zygomatic arch. Hypopharyngeal reconstruction was tested by transposing the flap to the neck under the facial nerve. RESULTS: After latex injection, a rich vascular network over the temporoparietal galea was observed directly from the superficial temporal artery, and a well-vascularized flap based on this vessel was raised. In the reconstruction simulations, the flap was shown to be suitable for the coverage of hypothetical defects in most oral cavity and pharyngeal sites, mainly the retromolar trigone, tonsil area, and buccal mucosa. CONCLUSIONS: A galeal flap based on the superficial temporal vessels presents favorable anatomical characteristics for oral cavity and pharyngeal reconstruction.

Fabio Pinto; Roberto Magalhães; Marcelo Durazzo; Lenine Brandão; Aldo Junqueira Rodrigues Jr.

2008-01-01

106

Anatomically based geometric modelling of the musculo-skeletal system and other organs.  

UK PubMed Central (United Kingdom)

Anatomically based finite element geometries are becoming increasingly popular in physiological modelling, owing to the demand for modelling that links organ function to spatially distributed properties at the protein, cell and tissue level. We present a collection of anatomically based finite element geometries of the musculo-skeletal system and other organs suitable for use in continuum analysis. These meshes are derived from the widely used Visible Human (VH) dataset and constitute a contribution to the world wide International Union of Physiological Sciences (IUPS) Physiome Project (www.physiome.org.nz). The method of mesh generation and fitting of tricubic Hermite volume meshes to a given dataset is illustrated using a least-squares algorithm that is modified with smoothing (Sobolev) constraints via the penalty method to account for sparse and scattered data. A technique ("host mesh" fitting) based on "free-form" deformation (FFD) is used to customise the fitted (generic) geometry. Lung lobes, the rectus femoris muscle and the lower limb bones are used as examples to illustrate these methods. Geometries of the lower limb, knee joint, forearm and neck are also presented. Finally, the issues and limitations of the methods are discussed.

Fernandez JW; Mithraratne P; Thrupp SF; Tawhai MH; Hunter PJ

2004-03-01

107

Functional and anatomic orientation of the femoral head.  

UK PubMed Central (United Kingdom)

BACKGROUND: Femoral neck geometry directly affects load transmission through the hip. Orientations may be described anatomically or using functional definitions that consider load transmission. QUESTIONS/PURPOSES: This study introduces and applies a new method for characterizing functional femoral orientation based on the distribution of subchondral bone density in the femoral head and compares it with orientation measures generated via established anatomic landmark-based methods. Both orientation methods then are used to characterize side-to-side symmetry of orientation and differences between men and women within the population. PATIENTS AND METHODS: A retrospective review of CT imaging data from 28 patients was performed. Anatomic orientation was determined using established two-dimensional and three-dimensional landmarking methods. Subchondral bone density maps were generated and used to define a density-weighted surface normal vector. Orientation angles generated by the three methods were compared, with side-to-side symmetry and differences between genders also investigated. RESULTS: The three methods measured substantially different angles for anteversion and neck-shaft angle. Weak correlations were found between anatomic and functional orientation measures for neck-shaft angle only. CONCLUSIONS: Neck-shaft angles calculated using the functional orientation method corresponded well with previous in vivo loading data. An absence of strong correlation between functional and anatomic measures reinforces the concept that bone geometry is not solely responsible for determining loading of the femoral head. LEVEL OF EVIDENCE: Level II, Diagnostic Studies--Investigating a Diagnostic Test. See the Guidelines for Authors for a complete description of levels of evidence.

Wright D; Whyne C; Hardisty M; Kreder HJ; Lubovsky O

2011-09-01

108

Anatomically based finite element models of the human pulmonary arterial and venous trees including supernumerary vessels.  

Science.gov (United States)

Studies of the origin of pulmonary blood flow heterogeneity have highlighted the significant role of vessel branching structure on flow distribution. To enable more detailed investigation of structure-function relationships in the pulmonary circulation, an anatomically based finite element model of the arterial and venous networks has been developed to more accurately reflect the geometry found in vivo. Geometric models of the arterial and venous tree structures are created using a combination of multidetector row X-ray computed tomography imaging to define around 2,500 vessels from each tree, a volume-filling branching algorithm to generate the remaining accompanying conducting vessels, and an empirically based algorithm to generate the supernumerary vessel geometry. The explicit generation of supernumerary vessels is a unique feature of the computational model. Analysis of branching properties and geometric parameters demonstrates close correlation between the model geometry and anatomical measures of human pulmonary blood vessels. A total of 12 Strahler orders for the arterial system and 10 Strahler orders for the venous system are generated, down to the equivalent level of the terminal bronchioles in the bronchial tree. A simple Poiseuille flow solution, assuming rigid vessels, is obtained within the arterial geometry of the left lung, demonstrating a large amount of heterogeneity in the flow distribution, especially with inclusion of supernumerary vessels. This model has been constructed to accurately represent available morphometric data derived from the complex asymmetric branching structure of the human pulmonary vasculature in a form that will be suitable for application in functional simulations. PMID:15802366

Burrowes, Kelly S; Hunter, Peter J; Tawhai, Merryn H

2005-03-31

109

Pitfalls at the root of facial assessment on photographs: a quantitative study of accuracy in positioning facial landmarks.  

UK PubMed Central (United Kingdom)

In the last years, facial analysis has gained great interest also for forensic anthropology. The application of facial landmarks may bring about relevant advantages for the analysis of 2D images by measuring distances and extracting quantitative indices. However, this is a complex task which depends upon the variability in positioning facial landmarks. In addition, literature provides only general indications concerning the reliability in positioning facial landmarks on photographic material, and no study is available concerning the specific errors which may be encountered in such an operation. The aim of this study is to analyze the inter- and intra-observer error in defining facial landmarks on photographs by using a software specifically developed for this purpose. Twenty-four operators were requested to define 22 facial landmarks on frontal view photographs and 11 on lateral view images; in addition, three operators repeated the procedure on the same photographs 20 times (at distance of 24 h). In the frontal view, the landmarks with less dispersion were the pupil, cheilion, endocanthion, and stomion (sto), and the landmarks with the highest dispersion were gonion, zygion, frontotemporale, tragion, and selion (se). In the lateral view, the landmarks with the least dispersion were se, pronasale, subnasale, and sto, whereas landmarks with the highest dispersion were gnathion, pogonion, and tragion. Results confirm that few anatomical points can be defined with the highest accuracy and show the importance of the preliminary investigation of reliability in positioning facial landmarks.

Cummaudo M; Guerzoni M; Marasciuolo L; Gibelli D; Cigada A; Obertovà Z; Ratnayake M; Poppa P; Gabriel P; Ritz-Timme S; Cattaneo C

2013-05-01

110

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

International Nuclear Information System (INIS)

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

2004-01-01

111

Landmark Discrimination Learning in the Dog  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Allocentric spatial memory was studied in dogs of varying ages and sources using a landmark discrimination task. The primary goal of this study was to develop a protocol to test landmark discrimination learning in the dog. Using a modified version of a landmark test developed for use in monkeys, we ...

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

112

3D facial landmark detection under large yaw and expression variations.  

UK PubMed Central (United Kingdom)

A 3D landmark detection method for 3D facial scans is presented and thoroughly evaluated. The main contribution of the presented method is the automatic and pose-invariant detection of landmarks on 3D facial scans under large yaw variations (that often result in missing facial data), and its robustness against large facial expressions. Three-dimensional information is exploited by using 3D local shape descriptors to extract candidate landmark points. The shape descriptors include the shape index, a continuous map of principal curvature values of a 3D object's surface, and spin images, local descriptors of the object's 3D point distribution. The candidate landmarks are identified and labeled by matching them with a Facial Landmark Model (FLM) of facial anatomical landmarks. The presented method is extensively evaluated against a variety of 3D facial databases and achieves state-of-the-art accuracy (4.5-6.3 mm mean landmark localization error), considerably outperforming previous methods, even when tested with the most challenging data.

Perakis P; Passalis G; Theoharis T; Kakadiaris IA

2013-07-01

113

Reorienting with terrain slope and landmarks.  

UK PubMed Central (United Kingdom)

Orientation (or reorientation) is the first step in navigation, because establishing a spatial frame of reference is essential for a sense of location and heading direction. Recent research on nonhuman animals has revealed that the vertical component of an environment provides an important source of spatial information, in both terrestrial and aquatic settings. Nonetheless, humans show large individual and sex differences in the ability to use terrain slope for reorientation. To understand why some participants--mainly women--exhibit a difficulty with slope, we tested reorientation in a richer environment than had been used previously, including both a tilted floor and a set of distinct objects that could be used as landmarks. This environment allowed for the use of two different strategies for solving the task, one based on directional cues (slope gradient) and one based on positional cues (landmarks). Overall, rather than using both cues, participants tended to focus on just one. Although men and women did not differ significantly in their encoding of or reliance on the two strategies, men showed greater confidence in solving the reorientation task. These facts suggest that one possible cause of the female difficulty with slope might be a generally lower spatial confidence during reorientation.

Nardi D; Newcombe NS; Shipley TF

2013-02-01

114

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.)

2009-01-01

115

Pontos referenciais nos acessos cranianos Landmarks to the cranial approaches  

Directory of Open Access Journals (Sweden)

Full Text Available O conhecimento da topografia cranioencefálica permite delimitar os acessos cranianos. Sistematiza-se os pontos referenciais, definidos em relação aos pontos craniométricos, usados nos diferentes acessos cranianos. Dos 22 pontos referenciais descritos, os doze primeiros estão em relação com a base do crânio e os demais com a convexidade.The knowledge of the craniotopography allows the delimitation of the cranial approaches. In this study the landmarks, defined in relation to the craniometric points and used in the different cranial approaches, were systematized. Twenty two landmarks are described: the first twelve are in relation to the skull base and the remainder are in relation to the skull vertex.

Sebastião Gusmão; Roberto Leal Silveira; Aluízio Arantes

2003-01-01

116

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

International Nuclear Information System (INIS)

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

2003-08-21

117

Discriminative BoW Framework for Mobile Landmark Recognition.  

UK PubMed Central (United Kingdom)

This paper proposes a new soft bag-of-words (BoW) method for mobile landmark recognition based on discriminative learning of image patches. Conventional BoW methods often consider the patches/regions in the images as equally important for learning. Amongst the few existing works that consider the discriminative information of the patches, they mainly focus on selecting the representative patches for training, and discard the others. This binary hard selection approach results in underutilization of the information available, as some discarded patches may still contain useful discriminative information. Further, not all the selected patches will contribute equally to the learning process. In view of this, this paper presents a new discriminative soft BoW approach for mobile landmark recognition. The main contribution of the method is that the representative and discriminative information of the landmark is learned at three levels: patches, images, and codewords. The patch discriminative information for each landmark is first learned and incorporated through vector quantization to generate soft BoW histograms. Coupled with the learned representative information of the images and codewords, these histograms are used to train an ensemble of classifiers using fuzzy support vector machine. Experimental results on two different datasets show that the proposed method is effective in mobile landmark recognition.

Chen T; Yap KH

2013-07-01

118

[Anatomic study and preliminary clinical application of the laterally based pericranial flap to treat traumatic enophthalmos].  

UK PubMed Central (United Kingdom)

OBJECTIVE: To assess the vascularization of the laterally based pericranial flap and the feasibility of bony channel on the orbital lateral wall for transplantation of the flap, and apply this flap to treat traumatic enophthalmos. METHODS: Two formalin preserved cadaver specimens were anatomized to observe the feasibility of pericranial flap transplantation through the bony channels on lateral orbital walls. Two fresh cadaver specimens were perfused with latex and ink respectively to observe the possible blood supply to laterally based pericranial flaps. Two patients with unilateral old orbital fracture were treated using this flap. The enophthalmos degrees were measured before and after operation to evaluate the effect of this therapy. RESULTS: It was feasible to transplant the pericranial flap into orbit through the bony channel on lateral orbital wall, reaching the medial wall and orbital floor. Vascular perfusion did not reveal that the laterally based pericranial flap over the supra temporal line was vascularized by any axial vessel. The ink perfusion of one side showed that the middle temporal artery extended deeply under the deep temporal fascia, but didn't cross the supra temporal line. The subgaleal vascular plexus was observed obviously in the superficial layer of pericranial flap. The enophthalmos degrees of the two patients were respectively 5.35 mm and 6.86 mm prior to operation. They both showed desirable outcomes postoperation (<2 mm). CONCLUSION: It is feasible to transfer the laterally based pericranial flap into orbit through the lateral orbital wall channel. The laterally based pericranial flap is possibly vascularized by the subgaleal vascular plexus. The primary treatment of traumatic enophthalmos using the laterally based pericranial flap is satisfactory.

He Y; Zhang Y; An JG

2011-10-01

119

A review of terminology for equine juvenile osteochondral conditions (JOCC) based on anatomical and functional considerations.  

UK PubMed Central (United Kingdom)

This manuscript describes a new classification of the various joint-related lesions that can be seen in the young, growing horse based on their anatomical and functional aetiopathogenesis. Juvenile osteochondral conditions (JOCC) is a term that brings together specific disorders according to their location in the joint and their biomechanical origin. When a biomechanical insult affects the process of endochondral ossification different types of osteochondrosis (OC) lesions may occur, including osteochondral fragmentation of the articular surface or of the periarticular margins, or the formation of juvenile subchondral bone cysts. In severe cases, osteochondral collapse of the articular surface or the epiphysis or even an entire small bone may occur. Tension on ligament attachments may cause avulsion fractures of epiphyseal (or metaphyseal) ossifying bone, which are classified as JOCC, but do not result from a disturbance of the process of endochondral ossification and are not therefore classified as a form of OC. The same applies to 'physitis' which can result from damage to the physeal growth plate.

Denoix JM; Jeffcott LB; McIlwraith CW; van Weeren PR

2013-07-01

120

A review of terminology for equine juvenile osteochondral conditions (JOCC) based on anatomical and functional considerations.  

Science.gov (United States)

This manuscript describes a new classification of the various joint-related lesions that can be seen in the young, growing horse based on their anatomical and functional aetiopathogenesis. Juvenile osteochondral conditions (JOCC) is a term that brings together specific disorders according to their location in the joint and their biomechanical origin. When a biomechanical insult affects the process of endochondral ossification different types of osteochondrosis (OC) lesions may occur, including osteochondral fragmentation of the articular surface or of the periarticular margins, or the formation of juvenile subchondral bone cysts. In severe cases, osteochondral collapse of the articular surface or the epiphysis or even an entire small bone may occur. Tension on ligament attachments may cause avulsion fractures of epiphyseal (or metaphyseal) ossifying bone, which are classified as JOCC, but do not result from a disturbance of the process of endochondral ossification and are not therefore classified as a form of OC. The same applies to 'physitis' which can result from damage to the physeal growth plate. PMID:23683533

Denoix, J-M; Jeffcott, L B; McIlwraith, C W; van Weeren, P R

2013-05-15

 
 
 
 
121

Modeling RBC and neutrophil distribution through an anatomically based pulmonary capillary network.  

Science.gov (United States)

An anatomically based finite element model of the human pulmonary microcirculation has been created and applied to simulating regional variations in blood flow. A geometric mesh of the capillary network over the surface of a single alveolar sac is created using a Voronoi meshing technique. A pressure-flow relationship that describes blood cell transit is implemented in the network. Regional flow is investigated by imposing gravity-dependent transpulmonary and transmural boundary conditions. Comparisons of red and white blood cell transit times in the upper, mid, and lower lung showed physiologically consistent trends of a decreasing average transit time and an increased homogeneity of transit time distributions as a result of increasing average capillary diameter and flow down the height of a vertical lung. The model was found to reproduce experimentally consistent trends in red blood cell transit times and relative blood flows with respect to lung height. This model enables flow properties and cell transit time behavior in the pulmonary microcirculation under varying conditions, for example in different "zones" of the lung, to be explored. PMID:15117032

Burrowes, Kelly S; Tawhai, Merryn H; Hunter, Peter J

2004-04-01

122

Impact of landmark parametrization on monocular EKF-SLAM with points and lines  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper explores the impact that landmark parametrization has in the performance of monocular, EKF-based, 6-DOF simultaneous localization and mapping (SLAM) in the context of undelayed landmark initialization. Undelayed initialization in monocular SLAM challenges EKF because of the combination of...

Solà, Joan; Vidal-Calleja, Teresa; Civera, Javier; Martinez-Monti, Jose Maria

123

Reproducibility of three-dimensional cephalometric landmarks in cone-beam and low-dose computed tomography.  

UK PubMed Central (United Kingdom)

OBJECTIVES: The purpose of this study is to compare the reproducibility of three-dimensional cephalometric landmarks on three-dimensional computed tomography (3D-CT) surface rendering using clinical protocols based on low-dose (35-mAs) spiral CT and cone-beam CT (I-CAT). The absorbed dose levels for radiosensitive organs in the maxillofacial region during exposure in both 3D-CT protocols were also assessed. MATERIALS AND METHODS: The study population consisted of ten human dry skulls examined with low-dose CT and cone-beam CT. Two independent observers identified 24 cephalometric anatomic landmarks at 13 sites on the 3D-CT surface renderings using both protocols, with each observer repeating the identification 1 month later. A total of 1,920 imaging measurements were performed. Thermoluminescent dosimeters were placed at six sites around the thyroid gland, the submandibular glands, and the eyes in an Alderson phantom to measure the absorbed dose levels. RESULTS: When comparing low-dose CT and cone-beam CT protocols, the cone-beam CT protocol proved to be significantly more reproducible for four of the 13 anatomical sites. There was no significant difference between the protocols for the other nine anatomical sites. Both low-dose and cone-beam CT protocols were equivalent in dose absorption to the eyes and submandibular glands. However, thyroid glands were more irradiated with low-dose CT. CONCLUSIONS: Cone-beam CT was more reproducible and procured less irradiation to the thyroid gland than low-dose CT. CLINICAL RELEVANCE: Cone-beam CT should be preferred over low-dose CT for developing three-dimensional bony cephalometric analyses.

Olszewski R; Frison L; Wisniewski M; Denis JM; Vynckier S; Cosnard G; Zech F; Reychler H

2013-01-01

124

Robot Navigation Using Panoramic Landmark Tracking  

UK PubMed Central (United Kingdom)

A vision based navigation system is presented for determininga mobile robot's position and orientation usingpanoramic imagery. Omni-directional sensors are usefulin obtaining afield of view, permitting objects in thevicinity of a robot to be imaged simultaneously. Recognizinglandmarks in a panoramic image from an a priori modelof distinct features in an environment allows a robot's locationinformation to be updated. A system is shown fortracking vertex and line features for omni-directional camerasconstructed with catadioptric (containing both mirrorsand lenses) optics. With the aid of the Panoramic HoughTransform, line features can be tracked without restrictingthe mirror geometry to that which satisfies the single viewpointcriteria. Two paradigms for landmark tracking are explored,with experiments shown with synthetic and real imagesreported. A working implementation on a mobile robotis shown.

Mark Fiala; Anup Basu

125

The island hemisoleus flap on distal vascular pedicle: anatomical bases and clinical applications.  

Science.gov (United States)

The coverage of skin defects of the ankle and of the distal fourth of the leg remains a difficult problem despite progress in reconstructive surgery. The aim of our study was to establish an arterial map of the lateral head of the soleus muscle, to compare it with the existing data in order to investigate the possibility of raising a fibular artery-based pedicle island reverse flow flap. It has the theoretical advantage over its medial counterpart of sparing the main arterial axis of the leg and foot. The anatomical study was undertaken on 15 fresh cadavers, 8 left and 7 right randomly chosen lower extremities from different subjects. For each calf, the following measurements were obtained: fibular length from the fibular head to the tip of the lateral malleolus; length of the lateral head of the soleus from its most proximal insertion point on the fibula to the most proximal part of the ending of the muscle belly on the Achilles tendon; width of the lateral head of the soleus; distance between the origin of the fibular artery and the tip of the fibular head; number and height of the pedicles for the lateral soleus, taking as reference their origin from the fibular artery. The mean dimensions of the muscle belly of the lateral soleus were 218 mm in length (between 160 and 270) and 73 mm in width (58-95). In all the examined lower extremities, we found a main pedicle for the lateral soleus emerging from the fibular artery; and in all cases the blood supply of the proximal part of the muscle was of a segmental distribution by way of multiple branches originating from the fibular artery. Then the flaps were raised with a distal pivot point represented by the perforating branch of the fibular artery. In all the cases, the flap would have covered an ankle or a dorsal foot defect up to the metatarsal heads. PMID:19415161

Le Nen, Dominique; Rizzo, C; Hu, W; Gérard, R; Oana, Dima; Lefèvre, C; Sénécail, B

2009-05-05

126

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

Scientific Electronic Library Online (English)

Full Text Available 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 septocutaneas individuales, el microcirujano reconstructivodebe tener la información anatómica detallada para planificar la transferencia de colgajos perforantes. El fin de este (more) 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 (more) 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.

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

2006-12-01

127

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

International Nuclear Information System (INIS)

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

2008-05-01

128

Assessment of potential orthodontic mini-implant insertion sites based on anatomical hard tissue parameters: a systematic review.  

UK PubMed Central (United Kingdom)

PURPOSE: To estimate the applicability of potential sites for insertion of orthodontic mini-implants (OMIs) by a systematic review of studies that used computed tomography (CT) or cone beam CT to evaluate anatomical bone quality and quantity parameters, such as bone thickness, available space, and bone density. MATERIALS AND METHODS: Medline and the Cochrane Database of Systematic Reviews were searched to identify all relevant papers. Several key words were used, such as computerized/computed tomography, mini-implants, and OMIs. The anatomical variables that were assigned in each article to a specific site suggesting it as the ideal or best alternative were assessed separately and evaluated with a scoring system. RESULTS: Twenty-two articles were included in the study. The most favorable areas for OMI insertion in the maxilla are proposed between the first and second molars buccally and palatally. The best area in the mandible is also between the first and second molars, both buccally and lingually. In the palate, the paramedian area 3 to 6 mm posterior to and 2 to 9 mm lateral to the incisive foramen was identified as the best site for OMI placement. CONCLUSIONS: Despite the heterogeneity of the studies, there was considerable agreement regarding the optimal site for OMI insertion among most studies that investigated anatomical hard tissue parameters based on CT or CBCT data. In this respect, the posterior area from the second premolar to the second molar is the best option for OMI placement in alveolar bone.

AlSamak S; Gkantidis N; Bitsanis E; Christou P

2012-07-01

129

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

International Nuclear Information System (INIS)

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

2007-01-01

130

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.

131

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

132

Dewatering induced settlement of a historic landmark  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Construction related dewatering in urban areas often induces damage of existing structures. The following forensic investigation highlights the complexities of such a phenomenon. Somerset plantation, a national historic landmark located in northeastern North Carolina is currently exhibiting distress...

Laefer, Debra F.; Frazier, Jon; Evans, Ashely

133

Determining functional connectivity using fMRI data with diffusion-based anatomical weighting.  

UK PubMed Central (United Kingdom)

There is strong interest in investigating both functional connectivity (FC) using functional magnetic resonance imaging (fMRI) and structural connectivity (SC) using diffusion tensor imaging (DTI). There is also emerging evidence of correspondence between functional and structural pathways within many networks (Greicius, et al., 2009; Skudlarski et al., 2008; van den Heuvel et al., 2009), although some regions without SC exhibit strong FC (Honey et al., 2008). These findings suggest that FC may be mediated by (direct or indirect) anatomical connections, offering an opportunity to supplement fMRI data with DTI data when determining FC. We develop a novel statistical method for determining FC, called anatomically weighted FC (awFC), which combines fMRI and DTI data. Our awFC approach implements a hierarchical clustering algorithm that establishes neural processing networks using a new distance measure consisting of two components, a primary functional component that captures correlations between fMRI signals from different regions and a secondary anatomical weight reflecting probabilities of SC. The awFC approach defaults to conventional unweighted clustering for specific parameter settings. We optimize awFC parameters using a strictly functional criterion, therefore our approach will generally perform at least as well as an unweighted analysis, with respect to intracluster coherence or autocorrelation. AwFC also yields more informative results since it provides structural properties associated with identified functional networks. We apply awFC to two fMRI data sets: resting-state data from 6 healthy subjects and data from 17 subjects performing an auditory task. In these examples, awFC leads to more highly autocorrelated networks than a conventional analysis. We also conduct a simulation study, which demonstrates accurate performance of awFC and confirms that awFC generally yields comparable, if not superior, accuracy relative to a standard approach.

Bowman FD; Zhang L; Derado G; Chen S

2012-09-01

134

Determining functional connectivity using fMRI data with diffusion-based anatomical weighting.  

Science.gov (United States)

There is strong interest in investigating both functional connectivity (FC) using functional magnetic resonance imaging (fMRI) and structural connectivity (SC) using diffusion tensor imaging (DTI). There is also emerging evidence of correspondence between functional and structural pathways within many networks (Greicius, et al., 2009; Skudlarski et al., 2008; van den Heuvel et al., 2009), although some regions without SC exhibit strong FC (Honey et al., 2008). These findings suggest that FC may be mediated by (direct or indirect) anatomical connections, offering an opportunity to supplement fMRI data with DTI data when determining FC. We develop a novel statistical method for determining FC, called anatomically weighted FC (awFC), which combines fMRI and DTI data. Our awFC approach implements a hierarchical clustering algorithm that establishes neural processing networks using a new distance measure consisting of two components, a primary functional component that captures correlations between fMRI signals from different regions and a secondary anatomical weight reflecting probabilities of SC. The awFC approach defaults to conventional unweighted clustering for specific parameter settings. We optimize awFC parameters using a strictly functional criterion, therefore our approach will generally perform at least as well as an unweighted analysis, with respect to intracluster coherence or autocorrelation. AwFC also yields more informative results since it provides structural properties associated with identified functional networks. We apply awFC to two fMRI data sets: resting-state data from 6 healthy subjects and data from 17 subjects performing an auditory task. In these examples, awFC leads to more highly autocorrelated networks than a conventional analysis. We also conduct a simulation study, which demonstrates accurate performance of awFC and confirms that awFC generally yields comparable, if not superior, accuracy relative to a standard approach. PMID:22634220

Bowman, F DuBois; Zhang, Lijun; Derado, Gordana; Chen, Shuo

2012-05-24

135

International variation in clinical injury incidence: exploring the performance of indicators based on health care, anatomical and outcome criteria.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To analyse international variation in clinical injury incidence, and explore the performance of different injury indicators in cross-country comparisons. METHODS: Hospital discharge data of seven European countries (Austria, Denmark, Ireland, Netherlands, Norway, England and Wales) were analysed. We tested existing and newly developed indicators based on (a) health care use, (b) anatomical criteria, or (c) expected health outcome: admissions excluding day-cases (a), hospital stay 4+ (a) and 7+ days (a), (serious) long-bone fractures (b), selected radiological verifiable fractures 'SRVFs' (b), and indicators based on international (Global Burden of Disease) and Dutch disability weights). Assessment criteria were reduction in incidence variation and length of stay in hospital, and the association between incidence and mortality rates. RESULTS: Indicators based on health care use led to increased variation in incidence rates. Long bone fractures and SRVFs, and both indicators based on injuries with moderate to high disability showed similar variation in clinical incidence compared to the crude rates, smaller variation in median length of stay in hospital and a good association with mortality rates. CONCLUSION: No perfect or near perfect indicators of clinical injury incidence exist. For international comparisons, indicators based on disability weights, SRVFs and long bone fractures may be sensible indicators to use, in the absence of a direct measure of anatomical severity.

Polinder S; Meerding WJ; Lyons RA; Haagsma JA; Toet H; Petridou ET; Mulder S; van Beeck EF

2008-01-01

136

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

2012-01-01

137

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

Scientific Electronic Library Online (English)

Full Text Available 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 o (more) f 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.

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

2012-02-01

138

The landmark citation method: analysis of a citation pattern as a collection assessment method.  

Science.gov (United States)

The landmark citation method is a new collection assessment method based on the citation record of a single landmark article. This citation record is developed by identifying sources which cite the landmark article. A bibliography, extracted from the citation record, is then used to complete an assessment of the collection. This method was developed and used to assess the biotechnology collection of the National Library of Medicine. The information gained from this study, in addition to demonstrating the technique, also provided insight into the evolution of the biotechnology literature. PMID:1422507

Soehner, C B; Wray, S T; Richards, D T

1992-10-01

139

The landmark citation method: analysis of a citation pattern as a collection assessment method.  

UK PubMed Central (United Kingdom)

The landmark citation method is a new collection assessment method based on the citation record of a single landmark article. This citation record is developed by identifying sources which cite the landmark article. A bibliography, extracted from the citation record, is then used to complete an assessment of the collection. This method was developed and used to assess the biotechnology collection of the National Library of Medicine. The information gained from this study, in addition to demonstrating the technique, also provided insight into the evolution of the biotechnology literature.

Soehner CB; Wray ST; Richards DT

1992-10-01

140

Design Guidelines for Landmarks to Support Navigation in Virtual Environments  

CERN Multimedia

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

Vinson, N G

2003-01-01

 
 
 
 
141

Design Optimization of Concentric Tube Robots Based on Task and Anatomical Constraints.  

UK PubMed Central (United Kingdom)

Concentric tube robots are a novel continuum robot technology that is well suited to minimally invasive surgeries inside small body cavities such as the heart. These robots are constructed of concentrically combined pre-curved elastic tubes to form 3D curves. Each telescopic section of the robot is either of fixed or variable curvature. One advantage of this approach is that the component tube curvatures, lengths and stiffnesses can easily be fabricated to be procedure- and patient-specific. This paper proposes an optimization framework for solving the robot design problem. Given a 3D description of the constraining anatomy, the number of fixed and variable curvature robot sections and a tip workspace description, the algorithm solves for the robot design that possesses the desired workspace, remains inside the anatomical constraints and minimizes the curvature and length of all sections. The approach is illustrated in the context of beating-heart closure of atrial septal defects.

Bedell C; Lock J; Gosline A; Dupont PE

2011-05-01

142

Design Optimization of Concentric Tube Robots Based on Task and Anatomical Constraints.  

Science.gov (United States)

Concentric tube robots are a novel continuum robot technology that is well suited to minimally invasive surgeries inside small body cavities such as the heart. These robots are constructed of concentrically combined pre-curved elastic tubes to form 3D curves. Each telescopic section of the robot is either of fixed or variable curvature. One advantage of this approach is that the component tube curvatures, lengths and stiffnesses can easily be fabricated to be procedure- and patient-specific. This paper proposes an optimization framework for solving the robot design problem. Given a 3D description of the constraining anatomy, the number of fixed and variable curvature robot sections and a tip workspace description, the algorithm solves for the robot design that possesses the desired workspace, remains inside the anatomical constraints and minimizes the curvature and length of all sections. The approach is illustrated in the context of beating-heart closure of atrial septal defects. PMID:22229108

Bedell, Chris; Lock, Jesse; Gosline, Andrew; Dupont, Pierre E

2011-05-01

143

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

2012-12-30

144

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

UK PubMed Central (United Kingdom)

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.

Sinclair J; Taylor PJ; Greenhalgh A; Edmundson CJ; Brooks D; Hobbs SJ

2012-12-01

145

Anatomic characteristics and radiographic references of the anterolateral and posteromedial bundles of the posterior cruciate ligament.  

UK PubMed Central (United Kingdom)

BACKGROUND: Anatomic graft tunnel placement is reported to be essential in double-bundle posterior cruciate ligament (PCL) reconstruction. A measurement system that correlates anatomy and radiographs is lacking so far. PURPOSE: To define the femoral and tibial attachments of the anterolateral (AL) and posteromedial (PM) bundles and to correlate them with digital and radiographic images to establish a radiographic anatomy based on anatomic landmarks and evaluate whether radiographs can serve as an accurate method for intraoperative and postoperative assessments of tunnel placement. STUDY DESIGN: Descriptive laboratory study. METHODS: Fifteen human cadaveric knee specimens were used. After preparation, the insertion areas of the 2 fiber bundles were marked with colorants, and high-definition digital images were obtained. With radiopaque tubes placed in the center of each bundle's footprint, anteroposterior and lateral radiographs were created. A measurement grid system was superimposed to determine the position of the AL and PM bundles' femoral and tibial insertion areas on both digital images and radiographs. The measurement zones were numbered 1 to 16, starting in the anterosuperior corner and ending in the posteroinferior corner. RESULTS: On radiographs and digital images, the femoral centers of the AL and PM bundles were found in zones 2 and 7, respectively. The tibial centers of the AL and PM bundles were found at 47.88% and 50.93%, respectively, of the total mediolateral diameter, 83.09% and 92.29%, respectively, of the total anteroposterior diameter, and 3.53 mm and 8.57 mm, respectively, inferior from the tibial plateau on radiographs. CONCLUSION: This study provides a geometric characterization of the AL and PM bundles of the PCL and establishes a reliable and feasible correlation system between anatomy and radiography based on anatomic landmarks. CLINICAL RELEVANCE: Accurate definition of the insertion sites of the PCL is essential for anatomic double-bundle reconstruction. The results of our study may be used as a reference for intraoperative and postoperative assessments of correct femoral and tibial tunnel placements.

Osti M; Tschann P; Künzel KH; Benedetto KP

2012-07-01

146

The dorsal pedis artery as a new distal landmark for extramedullary tibial alignment in total knee arthroplasty.  

UK PubMed Central (United Kingdom)

PURPOSE: It is better to use multiple anatomical landmarks to reduce errors in component alignment in total knee arthroplasty. Therefore, it is worthwhile to find a new landmark that can be used as an addition to conventional ones. Herein, we assessed the dorsal pedis artery as a new distal landmark for extramedullary tibial alignment. METHODS: Fifty-two ankles in patients undergoing total knee arthroplasty and 10 ankles in normal controls were included. Color Doppler ultrasonography was used to locate the dorsal pedis artery at the level of the ankle joint. Conventional landmarks, including the tibialis anterior tendon, the extensor hallucis longus tendon, the extensor digitorum longus tendon, and the malleolar centre, were also located on ultrasound images. The distances between the ankle centre and each landmark were measured and compared. RESULTS: The dorsal pedis artery was absent in 2 patients and impalpable but visible with ultrasonography in other 2 patients. The dorsal pedis artery was located anatomically closest to the ankle centre in patients (0.4 ± 3.4 mm lateral). Statistical analysis showed that the dorsal pedis artery, the extensor hallucis longus tendon, and the malleolar centre were located significantly closer to the ankle centre comparing with the extensor digitorum longus tendon and the tibialis anterior tendon in both patients and controls (p < 0.001). CONCLUSIONS: As long as the dorsal pedis artery exists, it can be used as an addition to the conventional landmarks in total knee arthroplasty. Using this new landmark will help reduce errors in coronal plane alignment of tibial component. LEVEL OF EVIDENCE: II.

Sugimura N; Ikeuchi M; Izumi M; Aso K; Ushida T; Tani T

2013-02-01

147

Observer Reliability in identification of Three-Dimensional Cephalometric Landmarks on CBCT Images  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract:Background and Aim: An important step before establishing CBCT as a common orthodontic diagnostic approach is to assess landmark reliability. The purpose of the present study was to evaluate intra- and inter observer reliability in 3D landmark identification using CBCT images.Materials and Methods: A total of 30 CBCT images were selected for this experimental study. Working independently, two observers identified 14 landmarks, twice in the CBCT images. Selecting the most appropriate slice in the axial, coronal, and sagittal views, the position of the landmark was recorded in millimeters for the X, Y, and Z coordinates respectively. Intra- and inter observer reliability values were determined using Pearson’s correlation test.Results: The Intra class correlation (ICC) was >0.7 for 97.6% of intra observer assessments and 92.8% of inter observer assessments. None of the ICCs were <0.6. The ICC was ?0.9 for 25 (59.5%) of the intra observer assessments. The ICC was ?0.9 for 28 (66.67%) of the inter observer assessments. The mean differences between the two observers in 95.2% of the cases were less than 2 millimeters.Conclusions: Considering the limitations and the results of the present study, the intra- and inter observer reliability was high. With proper training of the operator, the three-dimensional landmark identification using CBCT can offer consistent and reproducible data.Key words: Anatomic Landmarks; Cephalometry; Cone Beam CTJournal Res Dent Sci 2013;10(3): 192-199

Ghaffari R; Saghaie; Sheikhi M

2013-01-01

148

Automatic Dent-landmark detection in 3-D CBCT dental volumes.  

UK PubMed Central (United Kingdom)

Orthodontic craniometric landmarks provide critical information in oral and maxillofacial imaging diagnosis and treatment planning. The Dent-landmark, defined as the odontoid process of the epistropheus, is one of the key landmarks to construct the midsagittal reference plane. In this paper, we propose a learning-based approach to automatically detect the Dent-landmark in the 3D cone-beam computed tomography (CBCT) dental data. Specifically, a detector is learned using the random forest with sampled context features. Furthermore, we use spacial prior to build a constrained search space other than use the full three dimensional space. The proposed method has been evaluated on a dataset containing 73 CBCT dental volumes and yields promising results.

Cheng E; Chen J; Yang J; Deng H; Wu Y; Megalooikonomou V; Gable B; Ling H

2011-01-01

149

Perceptual organization and artificial attention for visual landmarks detection.  

UK PubMed Central (United Kingdom)

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

Antúnez E; Palomino AJ; Marfil R; Bandera JP

2013-03-01

150

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

UK PubMed Central (United Kingdom)

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

Schunke AC; Bromiley PA; Tautz D; Thacker NA

2012-01-01

151

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

Directory of Open Access Journals (Sweden)

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

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

2012-01-01

152

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

Directory of Open Access Journals (Sweden)

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

Houyel Lucile; Khoshnood Babak; Anderson Robert H; Lelong Nathalie; Thieulin Anne-Claire; Goffinet François; Bonnet Damien

2011-01-01

153

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

UK PubMed Central (United Kingdom)

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

Zamora N; Llamas JM; Cibrián R; Gandia JL; Paredes V

2012-07-01

154

Radiographic landmarks for measurement of cranial tibial subluxation in the canine cruciate ligament deficient stifle.  

UK PubMed Central (United Kingdom)

OBJECTIVES: The primary objective was to develop a repeatable radiographic technique for assessment of cranial tibial subluxation (CTS) and test the intra-observer and inter-observer repeatability of the chosen landmarks. A secondary objective was to determine the effects of digital radiographic magnification on CTS measurement repeatability. METHODS: Twenty-three normal canine pelvic limbs were used to determine the magnitude of CTS before and after transection of the cranial cruciate ligament. Mediolateral radiographs were taken with and without fiduciary markers in place. Three investigators measured the CTS using radiographically visible anatomic landmarks at two different magnifications. The total observed variabilities were assessed by inter-observer and intra-observer differences. Paired t-tests were used to determine the effect of magnification and marker presence on CTS measures. RESULTS: Measurement of the CTS from the caudal margin of the intercondylar fossa on the femur to the intercondylar eminence was the most repeatable. Poor correlation between the anatomic landmarks and the fiduciary bone markers was observed. We found no effect of magnification or presence or absence of bone markers on measurement of CTS. CLINICAL SIGNIFICANCE: Cranial tibial subluxation can be detected with the most repeatability by measuring between the caudal margin of the intercondylar fossa and the intercondylar eminence. Magnification of the digitized radiographic image had minimal effect on repeatability. This technique can be used for in vivo analysis of the canine cruciate ligament deficient stifle joint.

Plesman R; Sharma A; Gilbert P; Campbell J; Johnston JD; Shmon C; Linn K

2012-11-01

155

Homing in pigeons: the role of the hippocampal formation in the representation of landmarks used for navigation.  

UK PubMed Central (United Kingdom)

When given repeated training from a location, homing pigeons acquire the ability to use familiar landmarks to navigate home. Both control and hippocampal-lesioned pigeons succeed in learning to use familiar landmarks for homing. However, the landmark representations that guide navigation are strikingly different. Control and hippocampal-lesioned pigeons were initially given repeated training flights from two locations. On subsequent test days from the two training locations, all pigeons were rendered anosmic to eliminate use of their navigational map and were phase- or clock-shifted to examine the extent to which their learned landmark representations were dependent on the use of the sun as a compass. We show that control pigeons acquire a landmark representation that allows them to directly use landmarks without reference to the sun to guide their flight home, called "pilotage". Hippocampal-lesioned birds only learn to use familiar landmarks at the training location to recall the compass direction home, based on the sun, flown during training, called "site-specific compass orientation." The results demonstrate that for navigation of 20 km or more in a natural field setting, the hippocampal formation is necessary if homing pigeons are to learn a spatial representation based on numerous independent landmark elements that can be used to directly guide their return home.

Gagliardo A; Ioalé P; Bingman VP

1999-01-01

156

Homing in pigeons: the role of the hippocampal formation in the representation of landmarks used for navigation.  

Science.gov (United States)

When given repeated training from a location, homing pigeons acquire the ability to use familiar landmarks to navigate home. Both control and hippocampal-lesioned pigeons succeed in learning to use familiar landmarks for homing. However, the landmark representations that guide navigation are strikingly different. Control and hippocampal-lesioned pigeons were initially given repeated training flights from two locations. On subsequent test days from the two training locations, all pigeons were rendered anosmic to eliminate use of their navigational map and were phase- or clock-shifted to examine the extent to which their learned landmark representations were dependent on the use of the sun as a compass. We show that control pigeons acquire a landmark representation that allows them to directly use landmarks without reference to the sun to guide their flight home, called "pilotage". Hippocampal-lesioned birds only learn to use familiar landmarks at the training location to recall the compass direction home, based on the sun, flown during training, called "site-specific compass orientation." The results demonstrate that for navigation of 20 km or more in a natural field setting, the hippocampal formation is necessary if homing pigeons are to learn a spatial representation based on numerous independent landmark elements that can be used to directly guide their return home. PMID:9870960

Gagliardo, A; Ioalé, P; Bingman, V P

1999-01-01

157

Landmark papers on photorefractive nonlinear optics  

CERN Multimedia

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

158

Remembered landmarks enhance the precision of path integration  

Directory of Open Access Journals (Sweden)

Full Text Available When navigating by path integration, knowledge of one?s position becomes increasingly uncertain as one walks from a known location. This uncertainty decreases if one perceives a known landmark location nearby. We hypothesized that remembering landmarks might serve a similar purpose for path integration as directly perceiving them. If this is true, walking near a remembered landmark location should enhance response consistency in path integration tasks. To test this, we asked participants to view a target and then attempt to walk to it without vision. Some participants saw the target plus a landmark during the preview. Compared with no-landmark trials, response consistency nearly doubled when participants passed near the remembered landmark location. Similar results were obtained when participants could audibly perceive the landmark while walking. A control experiment ruled out perceptual context effects during the preview. We conclude that remembered landmarks can enhance path integration even though they are not directly perceived.

John W. Philbeck; Shannon O´Leary

2005-01-01

159

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

UK PubMed Central (United Kingdom)

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.

Matsushima K; Kawashima M; Matsushima T; Hiraishi T; Noguchi T; Kuraoka A

2013-08-01

160

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

International Nuclear Information System (INIS)

Purpose: To quantitatively compare a scanning liquid ion chamber electronic portal imaging device (SLIC-EPID) and an amorphous silicon flat panel (aSi) EPID with portal film in clinical applications using measures of landmark visibility and treatment review accuracy. Methods and Materials: Six radiation oncologists viewed 39 electronic portal images (EPIs) from the SLIC-EPID, 36 EPIs from the aSi-EPID, and portal films of each of these treatment fields. The physicians rated the clarity of anatomic landmarks in the portal images, and the scores were compared between EPID and film. Nine hundred portal image reviews were performed. EPID and film portal images were acquired with known setup errors in either phantom or cadaver treatments. Physicians identified the errors visually in portal films and with computerized analysis for EPID. Results: There were no statistically significant (p

2002-10-01

 
 
 
 
161

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

UK PubMed Central (United Kingdom)

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

Heath E; Collins DL; Keall PJ; Dong L; Seuntjens J

2007-11-01

162

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

UK PubMed Central (United Kingdom)

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.

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

2013-02-01

163

Radiographic landmarks for tunnel positioning in posterior cruciate ligament reconstructions.  

UK PubMed Central (United Kingdom)

BACKGROUND: Consistent radiographic guidelines for tunnel placement in single- or double-bundle posterior cruciate ligament (PCL) reconstructions are not well defined. Quantitative guidelines reporting the location of the individual PCL bundle attachments would aid in intraoperative tunnel placement and postoperative assessment of a PCL reconstruction. HYPOTHESIS: Consistent and reproducible measurements in relation to radiographic landmarks for the entire PCL and its individual bundle attachments are achievable. STUDY DESIGN: Controlled laboratory study. METHODS: The femoral and tibial PCL bundle attachment centers of 20 nonpaired fresh-frozen cadaveric knees were labeled using radio-opaque spheres and the attachment areas were labeled using barium sulfate. Anteroposterior (AP) and lateral radiographs of the femur and tibia were obtained, and measurements of the distances between the PCL bundle centers and landmarks were acquired. RESULTS: On the AP femur view, the anterolateral bundle (ALB) and posteromedial bundle (PMB) centers were 34.1 ± 3.0 mm and 29.2 ± 3.0 mm lateral to the most medial border of the medial femoral condyle, respectively. The lateral femur images revealed that the ALB center was 17.4 ± 1.7 mm and the PMB center was 23.9 ± 2.7 mm posteroproximal to a line perpendicular to the Blumensaat line that intersected the anterior margin of the medial femoral condyle cortex. Anteroposterior tibia images revealed that the ALB and PMB centers were located 0.2 ± 2.1 mm proximal and 4.9 ± 2.9 mm distal to the proximal joint line, respectively. The PCL attachment center was 1.6 ± 2.5 mm distal to the proximal joint line. On the lateral tibia view, the ALB center was 8.4 ± 1.8 mm, the PCL attachment center was 5.5 ± 1.7 mm, and the PMB center was 2.5 ± 1.5 mm superior to the champagne glass drop-off of the posterior tibia. CONCLUSION: Radiographic measurements from several clinically relevant views of the femur and tibia were reproducible with regard to the anatomic locations of the ALB and PMB centers. The measurements from the lateral femur and tibia views provided the most clinically pertinent radiographic measurements intraoperatively. CLINICAL RELEVANCE: This study established a set of clinically relevant radiographic guidelines for anatomic reconstruction of the PCL. The parameters set forth in this study can be used in both the intraoperative and postoperative settings for both single- and double-bundle PCL reconstructions.

Johannsen AM; Anderson CJ; Wijdicks CA; Engebretsen L; LaPrade RF

2013-01-01

164

Landmark recognition for underground robotics  

Energy Technology Data Exchange (ETDEWEB)

The development of a neural network based on IGI (Indirect Generalized Inverse) Bi-directional Associative Memory (BAM) is presented in this paper. As a part of an autonomous navigation system, the developed neural network is used to recognize video images from an underground coal mine. Computer simulation shows that the recognition system has a greatly improved performance over the well known Kosko BAM in recognition of underground mine images. 8 refs., 1 fig., 3 tabs.

Li, P.; Nutter, R.S. (West Virginia University, Morgantown, WV (USA). Electrical and Computer Engineering)

1992-01-01

165

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

166

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

Directory of Open Access Journals (Sweden)

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

Natalia N. Kruglova

2013-01-01

167

Imaging-based right-atrial anatomy by computed tomography, magnetic resonance imaging, and three-dimensional transoesophageal echocardiography: correlations with anatomic specimens.  

UK PubMed Central (United Kingdom)

Nowadays computed tomography, cardiac magnetic resonance imaging, and tridimensional transoesophageal echocardiography provide anatomic images of right-atrial structures with an impressive richness of anatomical details. It is therefore surprising that these techniques are not routinely used as complementary tools in teaching anatomy. This review aims to fill this gap showing the normal anatomy of right atrium as displayed by these sophisticated imaging techniques. A better understanding of right-atrial anatomy is crucial for the treatment of primary right-atrium electrical disorders as well as for catheter-based interventions for structural heart disease. The success of these procedures is, in fact, related to an accurate anatomical pre-procedural assessment. In this review, we describe the normal anatomy and variants of those right-atrial structures relevant for both ablationists and interventionalists.

Faletra FF; Muzzarelli S; Dequarti MC; Murzilli R; Bellu R; Ho SY

2013-09-01

168

The effect of interface adhesion, water immersion and anatomical notches on the mechanical properties of denture base resins reinforced with continuous high performance polyethylene fibres.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Previous work has presented a study of the mechanical properties of denture base resins reinforced with a new type of high performance fibre. It is now shown that the substantial improvements demonstrated in those composites remain largely unaffected by a watery environment, anatomical notches, moul...

Ladizesky, NH; Chow, TW

169

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; Mehmet Tugrul Yilmaz; Demet Kiresi; Muzaffer Seker

2012-01-01

170

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

Scientific Electronic Library Online (English)

Full Text Available Abstract in spanish El objetivo de este estudio fue investigar el curso de los vasos faciales de acuerdo con varios puntos de referencias mandibulares en sujetos vivos mediante angiografía por tomografía computarizada multidetector (ATCM) para determinar si éstos están relacionados con el sexo y el lado. El estudio se llevó a cabo en el Departamento de Radiología, Facultad de Medicina de Meram en Necmettin Erbakan (Konya, Turkey). En total, sesenta caras de 30 sujetos (15 hombres y 15 (more) mujeres), que presentaban síntomas y signos de la enfermedad vascular fueron evaluados para explorar los vasos faciales por ATCM. Los parámetros sobre los vasos faciales se midieron en relación a puntos de referencia (ángulo de la mandíbula, proceso mental, foramen mental y línea mediana facial). La distancia desde el punto en el que la arteria facial aparece por primera vez en el margen inferior de la mandíbula hasta el ángulo mandibular de la arteria facial derecha y izquierda fueron 3,53±0,66 cm y 3,31±0,73 cm en hombres, respectivamente. En mujeres fueron 2,91±0,52 cm y 3,35± 0,48 cm. La ATCM es un examen nuevo, poderoso, seguro y no invasivo para demostrar la vascularización de la cabeza. Las estructuras óseas y la morfología de los vasos vecinos pueden ser evaluados por esta técnica en casos de trauma con sospecha de lesiones de los vasos y se puede considerar de selección en pacientes para realizar cirugías de colgajo. Abstract in english The aim of this study was to investigate the course of the facial vessels according to several mandibular landmarks in living individuals using multidetector computed tomography angiography (MDCTA) to determine these related to sex and side. This study was conducted in the Radiology Department, 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 disea (more) se 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.

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

2012-06-01

171

Statistical 3D prostate imaging atlas construction via anatomically constrained registration  

Science.gov (United States)

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

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

2013-03-01

172

Multivariate tensor-based brain anatomical surface morphometry via holomorphic one-forms.  

UK PubMed Central (United Kingdom)

Here we introduce multivariate tensor-based surface morphometry using holomorphic one-forms to study brain anatomy. We computed new statistics from the Riemannian metric tensors that retain the full information in the deformation tensor fields. We introduce two different holomorphic one-forms that induce different surface conformal parameterizations. We applied this framework to 3D MRI data to analyze hippocampal surface morphometry in Alzheimer's Disease (AD; 26 subjects), lateral ventricular surface morphometry in HIV/AIDS (19 subjects) and cortical surface morphometry in Williams Syndrome (WS; 80 subjects). Experimental results demonstrated that our method powerfully detected brain surface abnormalities. Multivariate statistics on the local tensors outperformed other TBM methods including analysis of the Jacobian determinant, the largest eigenvalue, or the pair of eigenvalues, of the surface Jacobian matrix.

Wang Y; Chan TF; Toga AW; Thompson PM

2009-01-01

173

Multivariate tensor-based brain anatomical surface morphometry via holomorphic one-forms.  

Science.gov (United States)

Here we introduce multivariate tensor-based surface morphometry using holomorphic one-forms to study brain anatomy. We computed new statistics from the Riemannian metric tensors that retain the full information in the deformation tensor fields. We introduce two different holomorphic one-forms that induce different surface conformal parameterizations. We applied this framework to 3D MRI data to analyze hippocampal surface morphometry in Alzheimer's Disease (AD; 26 subjects), lateral ventricular surface morphometry in HIV/AIDS (19 subjects) and cortical surface morphometry in Williams Syndrome (WS; 80 subjects). Experimental results demonstrated that our method powerfully detected brain surface abnormalities. Multivariate statistics on the local tensors outperformed other TBM methods including analysis of the Jacobian determinant, the largest eigenvalue, or the pair of eigenvalues, of the surface Jacobian matrix. PMID:20426005

Wang, Yalin; Chan, Tony F; Toga, Arthur W; Thompson, Paul M

2009-01-01

174

Bilateral participation of the hippocampus in familiar landmark navigation by homing pigeons.  

Science.gov (United States)

Recent findings indicate a different role of the left and right hippocampal formation (RHF) in homing pigeon navigational map learning. However, it remains uncertain whether the left or the RHF may play a more important role in navigation based on familiar landmarks. In the present study, we attempted to answer this question by experimentally releasing control and left and right hippocampal ablated pigeons from familiar training sites under anosmia, to render their navigational map dysfunctional, and after a phase-shift of the light-dark cycle, to place into conflict a pilotage-like landmark navigational strategy and a site-specific compass orientation landmark navigational strategy. Both left and right hippocampal ablated birds succeeded in learning to navigate by familiar landmarks, and both preferentially relied on sun-compass based, site-specific compass orientation to home. Like bilateral hippocampal lesioned birds, and in contrast to intact controls, neither ablation group adopted a pilotage-like strategy. We conclude that both the left and RHF are necessary if pilotage-like, familiar landmark navigation is to be learned or preferentially used for navigation. PMID:12385806

Gagliardo, Anna; Odetti, Francesca; Ioalè, Paolo; Bingman, Verner P; Tuttle, Sarah; Vallortigara, Giorgio

2002-10-17

175

Bilateral participation of the hippocampus in familiar landmark navigation by homing pigeons.  

UK PubMed Central (United Kingdom)

Recent findings indicate a different role of the left and right hippocampal formation (RHF) in homing pigeon navigational map learning. However, it remains uncertain whether the left or the RHF may play a more important role in navigation based on familiar landmarks. In the present study, we attempted to answer this question by experimentally releasing control and left and right hippocampal ablated pigeons from familiar training sites under anosmia, to render their navigational map dysfunctional, and after a phase-shift of the light-dark cycle, to place into conflict a pilotage-like landmark navigational strategy and a site-specific compass orientation landmark navigational strategy. Both left and right hippocampal ablated birds succeeded in learning to navigate by familiar landmarks, and both preferentially relied on sun-compass based, site-specific compass orientation to home. Like bilateral hippocampal lesioned birds, and in contrast to intact controls, neither ablation group adopted a pilotage-like strategy. We conclude that both the left and RHF are necessary if pilotage-like, familiar landmark navigation is to be learned or preferentially used for navigation.

Gagliardo A; Odetti F; Ioalè P; Bingman VP; Tuttle S; Vallortigara G

2002-10-01

176

Using the landmark-route-survey framework to evaluate spatial knowledge obtained from synthetic vision systems.  

UK PubMed Central (United Kingdom)

OBJECTIVE: Using the landmark-route-survey framework, this research investigated the effect of synthetic vision systems (SVS) in either low or high visibility conditions on performance in wayfinding and spatial-knowledge-based tasks that probed spatial awareness. BACKGROUND: SVS are cockpit displays that depict computer-generated views of the terrain surrounding an aircraft and have been developed to support flight efficiency through improved spatial awareness. No studies have directly measured SVS impact on the three levels of spatial knowledge (landmark, route, and survey). METHOD: A total of 55 nonpilots learned a route in four different experimental conditions (high or low visibility, either with or without SVS). Subsequently, they underwent four recall tasks: way finding, scene recognition, scene classification, and sketch map. Six dependent measures were used to probe the three levels of spatial knowledge (selection errors, sorting errors, number of landmarks depicted, bidimensional regression) and their use in the wayfinding task (direction errors, designated landmark errors, and wayfinding verbalized hesitations). RESULTS: SVS produced higher performance in all four tasks. The low visibility condition lowered the wayfinding and scene-recognition performance. CONCLUSION: The overall results indicated that visibility mostly affected the first level of spatial knowledge (landmark) inducing a decreased wayfinding performance, whereas the use of SVS influenced the three levels of spatial knowledge (route and survey) inducing an increased wayfinding performance. APPLICATION: Potential applications of this work include spatial knowledge-based measures to evaluate SVS prototypes as well as to assess the relationship between spatial knowledge and spatial awareness.

Lapeyre B; Hourlier S; Servantie X; N'Kaoua B; Sauzéon H

2011-12-01

177

Voxel-based morphometric analysis in hypothyroidism using diffeomorphic anatomic registration via an exponentiated lie algebra algorithm approach.  

UK PubMed Central (United Kingdom)

The present study aimed to investigate whether brain morphological differences exist between adult hypothyroid subjects and age-matched controls using voxel-based morphometry (VBM) with diffeomorphic anatomic registration via an exponentiated lie algebra algorithm (DARTEL) approach. High-resolution structural magnetic resonance images were taken in ten healthy controls and ten hypothyroid subjects. The analysis was conducted using statistical parametric mapping. The VBM study revealed a reduction in grey matter volume in the left postcentral gyrus and cerebellum of hypothyroid subjects compared to controls. A significant reduction in white matter volume was also found in the cerebellum, right inferior and middle frontal gyrus, right precentral gyrus, right inferior occipital gyrus and right temporal gyrus of hypothyroid patients compared to healthy controls. Moreover, no meaningful cluster for greater grey or white matter volume was obtained in hypothyroid subjects compared to controls. Our study is the first VBM study of hypothyroidism in an adult population and suggests that, compared to controls, this disorder is associated with differences in brain morphology in areas corresponding to known functional deficits in attention, language, motor speed, visuospatial processing and memory in hypothyroidism.

Singh S; Modi S; Bagga D; Kaur P; Shankar LR; Khushu S

2013-03-01

178

Improving nodule detection in chest CT images using a cylindrical filter based on the anatomical structure of the lung  

International Nuclear Information System (INIS)

In a previous study, we developed a cylindrical filter for the detection of lung nodules in chest CT images. However, the detection rate of this method is reduced when nodules are adjacent to or overlap blood vessels or bronchi. The main objective of the present study was to develop a novel technique for improving the nodule detection capabilities of our method based on the anatomical structure of the bronchi and blood vessels obtained from CT images. In the proposed method, chest CT images are divided into a region consisting of normal lung structures (bronchi and blood vessels) and another region. Then, cylindrical filters with different characteristics are applied to the two regions. In order to evaluate the effectiveness of this method, the proposed method and the conventional method were applied to chest CT images, and their nodule detection capabilities were compared. The results showed that the true positive rate of the conventional method was 0.72, whereas that of the proposed method was 0.79. The number of false positives per case was 4.19 for both methods. These results indicate that the proposed method may be useful for improving nodule detection performance. (author)

2012-01-01

179

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

Science.gov (United States)

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

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

1998-06-01

180

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. Hum Brain Mapp, 2013. © 2013 Wiley Periodicals, Inc. 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

2013-05-14

 
 
 
 
181

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

International Nuclear Information System (INIS)

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

2011-01-01

182

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-09-15

183

[Anatomic features of the base of hearts with a solitary ventricle  

UK PubMed Central (United Kingdom)

Twenty-eight preparations of hearts having three chambers with two atria have been investigated. The age of the deceased was from several hours up to 21 years. Absence of the interventricular septum results in a complex rearrangement of the vessels in the basis cordis. Only in three cases the aorta and the pulmonary trunk situated typically, in others there was a complete transposition. Since the only ventricle, as a rule, is accompanied with a presence of a small chamber--"emissary", the topography of the vessels is mainly determined by the latter. The "emissary" is situated either along the right or left contour of the base of the common ventricle, its dimensions are variable. When the "emissary" is situated along the anterior-right contour of the basis cordis, as a rule, the aorta takes origin from the latter, its bulb is situated ventrally, initial parts of the venous arteries are visible. The cuspides of the aortal valve sag into the "emissary" lumen. When the aorta is situated normally, it can get off the cavity of the common ventricle, or the "emissary". The state of the children is determined first of all by the character of the pulmonary circulation. If there is no stenosis in the pulmonary trunk and it takes its origin from the common ventricle, or from the "emissary" of a great size, the prognosis is more favourable. Cases of early death among the children are connected with small size of the "emissary" chamber and a small diameter of the pulmonary trunk.(ABSTRACT TRUNCATED AT 250 WORDS)

Pekulin IV; Kir'iakulov GS; Shira AI

1985-08-01

184

Landmark risk prediction of residual life for breast cancer survival.  

Science.gov (United States)

The importance of developing personalized risk prediction estimates has become increasingly evident in recent years. In general, patient populations may be heterogenous and represent a mixture of different unknown subtypes of disease. When the source of this heterogeneity and resulting subtypes of disease are unknown, accurate prediction of survival may be difficult. However, in certain disease settings, the onset time of an observable short-term event may be highly associated with these unknown subtypes of disease and thus may be useful in predicting long-term survival. One approach to incorporate short-term event information along with baseline markers for the prediction of long-term survival is through a landmark Cox model, which assumes a proportional hazards model for the residual life at a given landmark point. In this paper, we use this modeling framework to develop procedures to assess how a patient's long-term survival trajectory may change over time given good short-term outcome indications along with prognosis on the basis of baseline markers. We first propose time-varying accuracy measures to quantify the predictive performance of landmark prediction rules for residual life and provide resampling-based procedures to make inference about such accuracy measures. Simulation studies show that the proposed procedures perform well in finite samples. Throughout, we illustrate our proposed procedures by using a breast cancer dataset with information on time to metastasis and time to death. In addition to baseline clinical markers available for each patient, a chromosome instability genetic score, denoted by CIN25, is also available for each patient and has been shown to be predictive of survival for various types of cancer. We provide procedures to evaluate the incremental value of CIN25 for the prediction of residual life and examine how the residual life profile changes over time. This allows us to identify an informative landmark point, t0 , such that accurate risk predictions of the residual life could be made for patients who survive past t0 without metastasis. Copyright © 2013 John Wiley & Sons, Ltd. PMID:23494768

Parast, Layla; Cai, Tianxi

2013-03-14

185

Ocular toxocariasis: epidemiologic, anatomic, and therapeutic variations based on a survey of ophthalmic subspecialists.  

UK PubMed Central (United Kingdom)

PURPOSE: To assess the current burden of ocular toxocariasis (OT) and to gain knowledge regarding the diagnostic and treatment practices used in the ophthalmologic community in the United States. DESIGN: Web-based, cross-sectional survey. PARTICIPANTS: Subspecialty ophthalmologists who are currently practicing in the United States. METHODS: An electronic survey was sent to 3020 ophthalmologic subspecialists belonging to the American Uveitis Society (AUS), the American Society of Retina Specialists (ASRS), or the American Association for Pediatric Ophthalmology and Strabismus (AAPOS) to capture demographic, clinical, diagnostic, and treatment data on patients with OT seen in their practices between September 2009 and September 2010. MAIN OUTCOME MEASURES: The demographic, epidemiologic, and clinical characteristics of each reported patient with OT. RESULTS: A total of 159 patients with OT were reported by 559 respondents (19%). The median patient age was 11.5 years (range, 1-66 years). Seventy-two patients (45%) with OT lived in the Southern region of the United States. Thirty-one (69%) of 45 patients with OT owned a dog or cat. Vision loss was reported in 46 (85%) of 54 patients with OT; 32 (71%) of 45 patients had permanent vision loss, 13 patients (29%) had temporary vision loss, and duration of vision loss was unreported for 1 patient. Of the 32 patients with OT with permanent vision loss, 30 (94%) had a subretinal granulomatous mass/scar, peripheral granuloma with traction bands, or posterior pole granuloma noted on ophthalmologic examination. Subretinal granulomatous mass/scar, vitritis, and scotoma were the most common ophthalmologic signs found on examination of patients with OT. CONCLUSIONS: Ocular toxocariasis continues to occur in the United States, where it affects mainly children and causes permanent vision loss in many patients. Healthcare professionals should counsel patients and their family members about prevention strategies in an effort to decrease infection rates and morbidity due to Toxocara. Further improvement of diagnostic and treatment tools is needed to assist ophthalmologists in treating patients with OT. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Woodhall D; Starr MC; Montgomery SP; Jones JL; Lum F; Read RW; Moorthy RS

2012-06-01

186

Acetabular orientation with different pelvic registration landmarks.  

Science.gov (United States)

This study determined the relationship of various pelvic landmarks to the pelvic plane in the lateral position. Five whole-body cadavers were used in this study. All navigation data were collected using the OrthoPilot navigation system (B. Braun Aesculap, Tuttlingen, Germany) to register all landmarks. The pelvic plane was registered with the body in the supine position for comparison. The ipsilateral posterosuperior iliac spine (PSIS) and contralateral PSIS were registered for comparison of the line made by the 2 anterosuperior iliac spines (ASIS) in the supine position. Registration points along the acetabular rim at the 12-, 3-, and 9-o'clock positions were recorded, and the transverse acetabular ligament (TAL) was registered using the ends and middle of the ligament for the 3 registration points. Inclination as determined by the TAL was 49.7 degrees +/-25.8 degrees , whereas the acetabular rim resulted in an inclination of 36.3 degrees +/-7.2 degrees . When the interspinal posterior line was calculated, the difference in inclination compared with the pelvic plane was 1.8 degrees +/-1.7 degrees . Anteversion using the acetabular rim resulted in a difference of 8.1 degrees +/-4.9 degrees and using the TAL resulted in a difference of 13.4 degrees +/-7.9 degrees . The difference in anteversion using the pelvic plane and the posterior interspinal line was 1.2 degrees +/-1.3 degrees . This study determined that the alternative landmarks of the acetabular rim and the TAL were not as accurate as using the posterior interspinal line as determined by registering the PSIS. PMID:19835300

Mihalko, William M; Kammerzell, Sergej; Saleh, Khaled J

2009-10-01

187

Acetabular orientation with different pelvic registration landmarks.  

UK PubMed Central (United Kingdom)

This study determined the relationship of various pelvic landmarks to the pelvic plane in the lateral position. Five whole-body cadavers were used in this study. All navigation data were collected using the OrthoPilot navigation system (B. Braun Aesculap, Tuttlingen, Germany) to register all landmarks. The pelvic plane was registered with the body in the supine position for comparison. The ipsilateral posterosuperior iliac spine (PSIS) and contralateral PSIS were registered for comparison of the line made by the 2 anterosuperior iliac spines (ASIS) in the supine position. Registration points along the acetabular rim at the 12-, 3-, and 9-o'clock positions were recorded, and the transverse acetabular ligament (TAL) was registered using the ends and middle of the ligament for the 3 registration points. Inclination as determined by the TAL was 49.7 degrees +/-25.8 degrees , whereas the acetabular rim resulted in an inclination of 36.3 degrees +/-7.2 degrees . When the interspinal posterior line was calculated, the difference in inclination compared with the pelvic plane was 1.8 degrees +/-1.7 degrees . Anteversion using the acetabular rim resulted in a difference of 8.1 degrees +/-4.9 degrees and using the TAL resulted in a difference of 13.4 degrees +/-7.9 degrees . The difference in anteversion using the pelvic plane and the posterior interspinal line was 1.2 degrees +/-1.3 degrees . This study determined that the alternative landmarks of the acetabular rim and the TAL were not as accurate as using the posterior interspinal line as determined by registering the PSIS.

Mihalko WM; Kammerzell S; Saleh KJ

2009-10-01

188

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

Directory of Open Access Journals (Sweden)

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

Peters Remco PH; Verweij Stephan P; Nijsten Noëmi; Ouburg Sander; Mutsaers Johan; Jansen Casper L; van Leeuwen A Petra; Morré Servaas A

2011-01-01

189

The use of radial symmetry to localize retinal landmarks.  

UK PubMed Central (United Kingdom)

Locating the optic disc center and the fovea in digital fundus images is surprisingly difficult due to the variation range in color and contrast and the possible presence of pathologies creating bright spots or changing the appearance of retinal landmarks. These reasons make it difficult to find good templates of optic disc and fovea shape and color for pattern matching. In this paper we propose radial symmetry as the principal cue to locate both optic disc and macula centers. Centers of bright and dark circularly symmetrical regions with arbitrary radii, can be found robustly against changes in brightness and contrast by using the Fast Radial Symmetry transform. Detectors based on this transform coupled with a weak hypothesis on vessel density (optic disc intersects large vessels while the fovea lies in an avascular region), can provide a fast location of both OD and macula with accuracy similar or better than state-of-the-art methods. The approach has been chosen as the default technique for fast localization of the two landmarks in the VAMPIRE software suite.

Giachetti A; Ballerini L; Trucco E; Wilson PJ

2013-07-01

190

Combining Path Integration and Remembered Landmarks When Navigating without Vision  

Science.gov (United States)

This study investigated the interaction between remembered landmark and path integration strategies for estimating current location when walking in an environment without vision. We asked whether observers navigating without vision only rely on path integration information to judge their location, or whether remembered landmarks also influence judgments. Participants estimated their location in a hallway after viewing a target (remembered landmark cue) and then walking blindfolded to the same or a conflicting location (path integration cue). We found that participants averaged remembered landmark and path integration information when they judged that both sources provided congruent information about location, which resulted in more precise estimates compared to estimates made with only path integration. In conclusion, humans integrate remembered landmarks and path integration in a gated fashion, dependent on the congruency of the information. Humans can flexibly combine information about remembered landmarks with path integration cues while navigating without visual information.

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

2013-01-01

191

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

Scientific Electronic Library Online (English)

Full Text Available 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 epilep (more) sy. 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

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

2005-03-01

192

A New 2D Corner Detector for Extracting Landmarks from Brain MR Images  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Point-based registration of images strongly depends on the extraction of suitable landmarks. Recently, various 2D operators have been proposed for the detection of corner points but most of them are not effective for medical images that need a high accuracy. In this paper we have proposed a new auto...

Mohammadi, Gelareh; Fatemizadeh, Emad

193

[Mediaeval anatomic iconography (Part II)  

UK PubMed Central (United Kingdom)

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.

Barg L

1996-01-01

194

Anatomic Total Shoulder System  

Medline Plus

Full Text Available ... harder down at the bottom. I think the best place to start is about right here, just ... inferiorly than the anatomic neck, and so the best place to define the anatomic neck is here ...

195

Anatomical Study of The Sacum for Transsacral Block of Sacral Nerves  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Inroduction: For transsacral block of sacral nerves in analgesia and anesthesia of the rectal, anal or urethral region the dorsal sacral foramina are used.To find solution of this by identifying additional anatomical landmarks and measurements of dorsal sacral foramina for transsacral nerve block. M...

D S Patil; H R Jadav; K B Chauhan; C R Bhatt; R Brahmbhatt

196

Bony landmarks as an aid for intraoperative facial nerve identification  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Identification of the facial nerve trunk is essential during surgery of the parotid gland. Numerous landmarks have been researched and used. The relation between the facial nerve to two constant bony landmarks, the tip of the mastoid process and the central point of the transverse process of the atl...

Greyling, Linda M.; Glanvill, R.; Boon, J.M.; Schabort, D.; Meiring, J.H.; Pretorius, Jan P.; Van Schoor, Albert-Neels

197

Sparse Decomposition and Modeling of Anatomical Shape Variation  

DEFF Research Database (Denmark)

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

Sjöstrand, Karl; Rostrup, Egill

2007-01-01

198

Sparse decomposition and modeling of anatomical shape variation  

DEFF Research Database (Denmark)

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

Sjöstrand, Karl; Rostrup, Egill

2007-01-01

199

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

2012-01-01

200

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

International Nuclear Information System (INIS)

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

1997-01-01

 
 
 
 
201

Supraclavicular approach to brachial plexus block using fluoroscopic anatomic landmarks and nerve stimulation.  

Science.gov (United States)

Irritation of neural structures, specifically the brachial plexus outside of the cervical spine is capable of producing pain in the upper extremity. These pain patterns may be similar to pain originating from the cervical spine, presenting a diagnostic challenge. Brachial plexus block is performed at multiple levels, including interscalene, supraclavicular, infraclavicular, and axillary. Interscalene block is frequently utilized by interventional pain management physicians for diagnostic and therapeutic purposes to isolate and manage the brachial plexus as a pain generator. The traditional methods employed in performing interscalene or supraclavicular brachial plexus blocks are associated with multiple disadvantages. A new technique is described to meet five essential requirements encompassing safety, specificity, consistency, reproducibility and a high success rate. Relevant anatomy and proposed technique of brachial plexus block is described. The procedure is performed under fluoroscopy with contrast injection. It is concluded that the proposed technique of brachial plexus block is useful for brachial plexus blockade providing precision and specificity with minimal complications. PMID:16883379

Vilims, Bradley D; Wright, Robert E

2003-04-01

202

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

International Nuclear Information System (INIS)

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

2002-01-01

203

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; Erika Hingst-Zaher; Hussam Zaher

2000-01-01

204

Technical note: A new method for measuring long bone curvature using 3D landmarks and semi-landmarks.  

UK PubMed Central (United Kingdom)

Here we describe and evaluate a new method for quantifying long bone curvature using geometric morphometric and semi-landmark analysis of the human femur. The technique is compared with traditional ways of measuring subtense and point of maximum curvature using either coordinate calipers or projection onto graph paper. Of the traditional methods the graph paper method is more reliable than using coordinate calipers. Measurement error is consistently lower for measuring point of maximum curvature than for measuring subtense. The results warrant caution when comparing data collected by the different traditional methods. Landmark data collection proves reliable and has a low measurement error. However, measurement error increases with the number of semi-landmarks included in the analysis of curvature. Measurements of subtense can be estimated more reliably using 3D landmarks along the curve than using traditional techniques. We use equidistant semi-landmarks to quantify the curve because sliding the semi-landmarks masks the curvature signal. Principal components analysis of these equidistant semi-landmarks provides the added benefit of describing the shape of the curve. These results are promising for functional and forensic analysis of long bone curvature in modern human populations and in the fossil record.

De Groote I; Lockwood CA; Aiello LC

2010-04-01

205

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

2005-01-01

206

Anatomical variability of the lateral frontal lobe surface: implication for intersubject variability in language neuroimaging.  

Science.gov (United States)

The lateral surface of the frontal lobe shows functional activation in a large number of language related tasks. Group analyses, however, demonstrate remarkable intersubject variability of activation. There are different sources for functional variability, anatomical variability being considered as one of them. The aim of the present study therefore was to qualitatively and quantitatively investigate the anatomical variability of the lateral frontal lobe surface and to search for reliable and stable landmarks connected to language functions. MRIs of 23 healthy right-handed subjects were investigated using the publicly available software "Anatomist/BrainVISA". After standardization of the brains (SPM) and sulci identification, the most frequent pattern was determined and the variance of selected landmarks calculated. The variability of the lateral frontal lobe surface is remarkable, particularly in the prefrontal region. Relatively stable landmarks were selected as follows: (1) connection between the superior frontal sulcus (SFS) and the superior precentral sulcus (SPCS); (2) connection between the inferior frontal sulcus (IFS) and the inferior precentral sulcus (IPCS); (3) inferior end of the precentral sulcus (PCS); and (4) origin of the ascending ramus (AscR) of the Sylvian fissure (SYF). The variability (standard deviation) of the spatial coordinates along the 3 axis of these landmarks after normalization ranged from 2.5 to 5.7 mm. The present study demonstrates that intersubject variability of selected landmarks of the frontal lobe surface remains notable even after spatial normalization of the brains. These results support the concept that anatomical variability is a relevant source of functional variability. We therefore suggest to express functional activation in relation to landmarks obtained from individual anatomy. This approach may contribute to a better analysis of the differences between individuals. PMID:15627592

Juch, Heike; Zimine, Ivan; Seghier, Mohamed L; Lazeyras, François; Fasel, Jean H D

2005-01-15

207

Algorithms to automatically quantify the geometric similarity of anatomical surfaces  

CERN Document Server

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

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

2011-01-01

208

Functionally Informed Cortex Based Alignment: An Integrated Approach for Whole-Cortex Macro-Anatomical and ROI-Based Functional Alignment.  

UK PubMed Central (United Kingdom)

Due to anatomical variability across subjects many brain mapping experiments choose to focus their analysis on a few particular regions of interest so as to circumvent the problem of sub-optimal statistics resulting from the lack of anatomical correspondence across subjects. Since the topographic distribution of experimental effects across the cortex is also often of interest, two separate analyses are often conducted, one on the regions of interest alone, as well as a separate 'whole brain' analysis with sub-optimal spatial correspondence across brains. In this paper we present a new group alignment procedure which incorporates, from each subject, both macro-anatomical (curvature) information and functional information from standard localizer experiments. After specifying appropriate parameters to weight anatomical and functional alignment forces, we were able to create a group cortical reconstruction which was well aligned in terms of both anatomical and functional areas. We observed an increase in the overlap of functional areas as well as an improvement in group statistics following this integrated alignment procedure. We propose that, using this alignment scheme, two separate analyses may not be necessary as both analyses can be integrated into a single procedure. After an integrated structural and functional alignment one is able to carry out a whole brain analysis with improved statistical sensitivity due to the reduction in spatial variation in the location of functional regions of interest which fCBA accomplishes. Furthermore, regions in the vicinity of localised and aligned regions-of-interest will also benefit from the integrated alignment.

Frost MA; Goebel R

2013-07-01

209

Proposal of landmarks for clamping neurovascular elements during endoscopic surgery of the supraglottic region.  

UK PubMed Central (United Kingdom)

BACKGROUND: Bleeding within the supraglottic region can be a lethal complication after CO(2) laser microsurgery. Our aim was to propose endoluminal anatomical landmarks to locate the superior laryngeal vessels resulting in a safer microsurgery. METHODS: Endoluminal dissections were made in 22 larynges without laryngeal disease. RESULTS: The neurovascular structures were in the superior third of a triangle defined by the vocal process, the anterior commissure, and the epiglottic attachment of the aryepiglottic fold. They overlapped in 4 different ways: pattern I (70.4%): superior laryngeal vein (SLV), superior laryngeal artery (SLA), and internal laryngeal nerve (ILN); pattern II (13.6%): SLA, SLV, ILN; pattern III (4.6%): SLV, ILN, and SLA; pattern IV (4.6%): SLA, ILN, and SLV. CONCLUSION: Microsurgery in the supraglottic region may be safer if surgeons are aware of the superior third of the above-defined triangle, "danger area", where the vascular elements of this region are located.

Souvirón R; Maranillo E; Vázquez T; Patel N; McHanwell S; Cobeta I; Scola B; Sañudo J

2013-01-01

210

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

211

Transpetrosal approach: an anatomical study of temporal bone.  

UK PubMed Central (United Kingdom)

Resection of the petrous temporal bone to various degrees provides different levels of access to lesions of the posterior fossa. However, regarding the numerous variations, precise distances of petrosal bone are not still clearly described. This may lead to serious complications during transpetrosal surgeries. Our objective was to evaluate different distances of temporal bone landmarks in order to assess their variations and the possible correlations between them. This anatomical study was performed on 60 temporal bones from 60 human cadavers in the years 2006 and 2007. All the bones contained an adequate portion of the petrous apex and attached fossa dura. Twelve landmarks were defined and 27 different distances were measured for each temporal bone using two-point caliper. Less variation was observed in the superoinferior diameter of horizontal carotid canal with the less coefficient of variation (CV) of 9.29; whereas, the most variation was detected in the inferior (axial) plane of posterior semicircular canal to superior plane of jugular bulb (CV = 57.65). There was a significant correlation between vertical intratemporal diameter of carotid in pyramidal direction, and superior-inferior diameter of horizontal carotid canal (r (Pearson) = 0.500, P < 0.001). Other significant correlations were also found between other distances. The variations of different distances and landmarks were evaluated and many significant correlations were demonstrated between them which could potentially aid ENT specialists and neurosurgeons in order to approach anatomical landmarks and cranial fossas more safely during otologic and neurotologic surgeries. It could also help the design of middle ear prosthesis.

Memari F; Tabatabaee RM; Borghei Razavi H; Fereshtehnejad SM; Daneshi A

2009-09-01

212

Anatomy and surgical landmarks for the ansa pectoralis: application to pectoralis major nerve selective neurotomy.  

UK PubMed Central (United Kingdom)

BACKGROUND: Ansa pectoralis neurotomy is a surgical approach in the treatment of the pectoralis major muscle spasticity causing an attitude in adduction and internal rotation of the shoulder. OBJECTIVE: To establish the anatomical landmarks allowing an easier localisation of the ansa pectoralis during neurotomy. MATERIAL AND METHODS: Fifteen adult human cadavers (10 embalmed and 5 fresh) were dissected in order to determine anatomical landmarks allowing an easier localization of the ansa pectoralis during neurotomy. RESULTS: In all the cadavers, the lateral pectoral nerve arose from the lateral cord of the brachial plexus, 0.2 cm above to 1.5 cm below the inferior border of the clavicle with a mean distance of 0.76 cm for left and right side, whereas the medial pectoral nerve arose from the medial cord of the brachial plexus, 0.7-2.3 cm below the inferior border of the clavicle with a mean distance of 0.61 cm for the left side and 0.68 cm for the right side. We systematically found both the origin of pectoral nerves and the ansa pectoralis at the level of the middle third of the distance between the sternoclavicular and the acromioclavicular joints. Moreover, ansa pectoralis was constantly localized lateral to the thoracoacromial artery. In four cases, the division of the lateral pectoral nerve was not found. In one case, medial pectoral nerve did not exist. CONCLUSION: Ansa pectoralis can be found by a curved incision made at the mid-third of the distance between the sternoclavicular and the acromioclavicular joints, the medial point being located just below the lower edge of the clavicle and the lateral point 2 cm below the inferior edge of the clavicle.

Creze M; Peltier J; Havet E; Potier A; Lefranc M; Foulon P; Le Gars D

2012-12-01

213

Radiographic landmarks for femoral tunnel placement in medial patellofemoral ligament reconstruction.  

UK PubMed Central (United Kingdom)

BACKGROUND: Reconstruction of the medial patellofemoral ligament has recently become popular for restoring patellofemoral stability. Femoral insertion site anatomy of the medial patellofemoral ligament has been described. This anatomical insertion has been inferred to be the isometric point in medial patellofemoral ligament reconstruction, but data about radiographic landmarks for a postoperative or intraoperative control are missing. PURPOSE: To determine the radiographic landmarks for control of postoperative and intraoperative femoral medial patellofemoral ligament insertion. STUDY DESIGN: Descriptive laboratory study. METHODS: Eight fresh-frozen human knees were dissected, and the medial patellofemoral ligament was exposed. After identification of the femoral medial patellofemoral ligament insertion site, the insertion center was marked with a lead ball of 2-mm diameter. Straight lateral radiographs were taken, and posterior-anterior as well as proximal-distal position were evaluated. RESULTS: Six of 8 insertion points were anterior to a line representing an extension of the posterior cortex, 1 point was touching this line, and 1 point was posterior to it. All points were situated distal to the posterior origin of the medial femoral condyle and proximal to the most posterior point of the Blumensaat line. CONCLUSION: A reproducible anatomical and radiographic point, 1 mm anterior to the posterior cortex extension line, 2.5 mm distal to the posterior origin of the medial femoral condyle, and proximal to the level of the posterior point of the Blumensaat line on a lateral radiograph with both posterior condyles projected in the same plane, shows the mean femoral medial patellofemoral ligament center. CLINICAL RELEVANCE: This radiographic point may be useful both intraoperatively and postoperatively.

Schöttle PB; Schmeling A; Rosenstiel N; Weiler A

2007-05-01

214

Anatomic Total Shoulder System  

Medline Plus

Full Text Available GLOBAL AP ANATOMIC TOTAL SHOULDER SYSTEM METHODIST HOSPITAL PHILADELPHIA, PA April 17, 2008 00:00:10 ANNOUNCER: DePuy Orthopedics ... ll be able to watch a live global AP anatomic total shoulder surgery from Methodist Hospital in ...

215

Sex differences in a landmark environmental re-orientation task only during the learning phase.  

UK PubMed Central (United Kingdom)

Sex differences are consistently reported in human navigation. Indeed, to orient themselves during navigation women are more likely to use landmark-based strategies and men Euclidean-based strategies. The difference could be due to selective social pressure, which fosters greater spatial ability in men, or biological factors. And the great variability of the results reported in the literature could be due to the experimental setting more than real differences in ability. In this study, navigational behaviour was assessed by means of a place-learning task in which a modified version of the Morris water maze for humans was used to evaluate sex differences. In using landmarks, sex differences emerged only during the learning phase. Although the men were faster than the women in locating the target position, the differences between the sexes disappeared in delayed recall.

Piccardi L; Bianchini F; Iasevoli L; Giannone G; Guariglia C

2011-10-01

216

Identifying intrasulcal medial surfaces for anatomically consistent reconstruction of the cerebral cortex  

Science.gov (United States)

A novel approach to identifying poorly resolved boundaries between adjacent sulcal cortical banks in MR images of the human brain is presented. The algorithm calculates an electrostatic potential field in a partial differential equation (PDE) model of an inhomogeneous dielectric layer of gray matter that surrounds conductive white matter. Correspondence trajectories and geodesic distances are computed along the streamlines of the potential field gradient using PDEs in a Eulerian framework. The skeleton of a sulcal medial boundary is identified by a simple procedure that finds irregularities/collisions in the field of correspondences. The skeleton detection procedure is robust to noise, does not produce spurious artifacts and does not require tunable parameters. Results of the algorithm are compared with a closely related technique, called Anatomically Consistent Enhancement (ACE) (Han et al. CRUISE: Cortical reconstruction using implicit surface evolution, 2004). Results demonstrate that the approach proposed here has a number of advantages over ACE and produces skeletons with a more regular structure. This algorithm was developed as a part of a more general PDE-based framework for cortical reconstruction, which integrates the potential field gradient flow and the skeleton barriers into a level set deformable model. This technique is primarily aimed at anatomically consistent and accurate reconstruction of cortical surface models in the presence of imaging noise and partial volume effects, but the identified intrasulcal medial surfaces can serve other purposes as well, e.g. as landmarks in nonrigid registration, or as sulcal ribbons that characterize the cortical folding.

Osechinskiy, Sergey; Kruggel, Frithjof

2011-03-01

217

Anatomical model-based finite element analysis of the combined cryosurgical and hyperthermic ablation for knee bone tumor.  

Science.gov (United States)

This paper is aimed at investigating the capacity of using combined cryosurgical and hyperthermic modality for treating knee bone tumor with complex shape. An anatomical model for human knee was constructed and a three-dimensional (3D) finite element analysis was developed to determine temperature distribution of the tissues subject to single freezing (SF), single heating (SH) and alternate freezing-heating (AFH), respectively. The heat fluxes of the probes wall and the ablation volume are particularly tracked to comparatively evaluate the ablation ability of different probe configurations with varied diameter, number and active working length. As example, an effective conformal treatment strategy via one time's insertion while cyclic freezing-heating using multiple probes is designed for a predefined knee bone tumor ablation. Both SF and SH could create large enough ablation volume, while it is hard for them to perform a conformal treatment on irregular and slender knee tumor. As an alternative, AFH could form a flexible and controlled shape and volume of the ablation by changing the size and number of the probes and adjusting their insertion depth. In addition, a thermal protection method is considered to reduce cryoinjury of the health tissue. PMID:24070544

He, Zhi Zhu; Xue, Xu; Xiao, Jian; Liu, Jing

2013-09-23

218

An anatomic study of the sacral hiatus: a basis for successful caudal epidural block.  

UK PubMed Central (United Kingdom)

STUDY DESIGN: An anatomic study of the sacral hiatus using isolated sacra. OBJECTIVES: To clarify the anatomic variations of the sacral hiatus using the bony landmarks of the sacrum for improving the reliability of caudal epidural block (CEB). BACKGROUND DATA: The CEB has been widely used for the diagnosis and treatment of lumbar spinal disorders. The reliability of CEB is 70%-80% in the literatures. The cause of failure of CEB may depend on anatomic basis. METHODS: A total of 92 isolated sacra were used in this study. The bony landmarks were sacral hiatus and sacral cornua. Morphologic types of the sacral hiatus were classified using these landmarks. Also, location of the apex of sacral hiatus, diameter of the sacral canal at the apex of sacral hiatus, and the distance between bilateral cornua were measured. Two orthopedic surgeons performed measurements independently. RESULTS: Forty-two percent of the cases have both hiatus and cornu. Four percent of the cases showed the absent hiatus. The apex of sacral hiatus existed at the level of S4 vertebrae in 64% of the cases. The average diameter of the sacral canal was 6.0 +/- 1.9 mm. The average distance of bilateral sacral cornua was 10.2 +/- 0.35 mm. There were closed hiatus in 3% of cases. CONCLUSIONS: The sacral hiatus has anatomic variations. Understanding of these variations may improve the reliability of CEB.

Sekiguchi M; Yabuki S; Satoh K; Kikuchi S

2004-01-01

219

[Anatomic considerations on the pyramid and nasal septum. Quantitative data apropos of 33 dissections on fresh corpses  

UK PubMed Central (United Kingdom)

The authors have dissected a series of nasal pyramids and septum. The various a anatomical structures have been measured and their relations with surgical landmarks have been recorded. Histograms show their findings. Surgical interest was emphasized for each stage of dissection. Some important points have been noticed during this study. They could bring some explanations to certain failures encountered after a septorhinoplasty.

Soudant J; Szalay M; Lamas G; Chic M; Beltran M

1989-01-01

220

On landmark selection and sampling in high-dimensional data analysis  

CERN Multimedia

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

Belabbas, Mohamed-Ali

2009-01-01

 
 
 
 
221

Landmark image super-resolution by retrieving web images.  

UK PubMed Central (United Kingdom)

This paper proposes a new super-resolution (SR) scheme for landmark images by retrieving correlated web images. Using correlated web images significantly improves the exemplar-based SR. Given a low-resolution (LR) image, we extract local descriptors from its up-sampled version and bundle the descriptors according to their spatial relationship to retrieve correlated high-resolution (HR) images from the web. Though similar in content, the retrieved images are usually taken with different illumination, focal lengths, and shot perspectives, resulting in uncertainty for the HR detail approximation. To solve this problem, we first propose aligning these images to the up-sampled LR image through a global registration, which identifies the corresponding regions in these images and reduces the mismatching. Second, we propose a structure-aware matching criterion and adaptive block sizes to improve the mapping accuracy between LR and HR patches. Finally, these matched HR patches are blended together by solving an energy minimization problem to recover the desired HR image. Experimental results demonstrate that our SR scheme achieves significant improvement compared with four state-of-the-art schemes in terms of both subjective and objective qualities.

Yue H; Sun X; Yang J; Wu F

2013-12-01

222

Landmark image super-resolution by retrieving web images.  

Science.gov (United States)

This paper proposes a new super-resolution (SR) scheme for landmark images by retrieving correlated web images. Using correlated web images significantly improves the exemplar-based SR. Given a low-resolution (LR) image, we extract local descriptors from its up-sampled version and bundle the descriptors according to their spatial relationship to retrieve correlated high-resolution (HR) images from the web. Though similar in content, the retrieved images are usually taken with different illumination, focal lengths, and shot perspectives, resulting in uncertainty for the HR detail approximation. To solve this problem, we first propose aligning these images to the up-sampled LR image through a global registration, which identifies the corresponding regions in these images and reduces the mismatching. Second, we propose a structure-aware matching criterion and adaptive block sizes to improve the mapping accuracy between LR and HR patches. Finally, these matched HR patches are blended together by solving an energy minimization problem to recover the desired HR image. Experimental results demonstrate that our SR scheme achieves significant improvement compared with four state-of-the-art schemes in terms of both subjective and objective qualities. PMID:23974626

Yue, Huanjing; Sun, Xiaoyan; Yang, Jingyu; Wu, Feng

2013-08-21

223

Desert ants benefit from combining visual and olfactory landmarks.  

UK PubMed Central (United Kingdom)

The desert ant, Cataglyphis fortis, uses both visual and olfactory cues to guide its return to the nest. The ants use vision-based path integration for long-distance navigation and memorize the visual and olfactory surrounding of the nest to finally locate the entrance. In the present study we investigated how the visual and the olfactory navigation systems interact. In field experiments ants were trained to associate the nest with a visual cue, an olfactory cue or a combination of both cues. We tested ants after one, five and 15 training runs, to investigate whether the ants would make use of the training cues to pinpoint the nest. We found that they were slow to learn the location of the nest when it was specified by just an olfactory or a visual cue. However, the ants focused their nest search after the first training run with the combined cue. Equally experienced ants responded to the individually presented visual or olfactory cues with the same high accuracy as they did to the combined cue. After 15 training runs, the combined cue still evoked an accurate response in the test, whereas the individually presented cues no longer did. Apparently, C. fortis benefit from combining their visual and olfactory navigational tools, because the bimodal sensory input accelerates the acquisition of landmark information.

Steck K; Hansson BS; Knaden M

2011-04-01

224

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

Science.gov (United States)

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

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

2012-11-27

225

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

UK PubMed Central (United Kingdom)

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

Lochner SJ; Huissoon JP; Bedi SS

2012-11-01

226

Landmark learning by the Ozark zigzag salamander Plethodon angusticlavius  

Directory of Open Access Journals (Sweden)

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

Adam L. CRANE, Alicia MATHIS

2011-01-01

227

Evidence for discrete landmark use by pigeons during homing.  

UK PubMed Central (United Kingdom)

Considerable efforts have been made to investigate how homing pigeons (Columba livia f. domestica) are able to return to their loft from distant, unfamiliar sites while the mechanisms underlying navigation in familiar territory have received less attention. With the recent advent of global positioning system (GPS) data loggers small enough to be carried by pigeons, the role of visual environmental features in guiding navigation over familiar areas is beginning to be understood, yet, surprisingly, we still know very little about whether homing pigeons can rely on discrete, visual landmarks to guide navigation. To assess a possible role of discrete, visual landmarks in navigation, homing pigeons were first trained to home from a site with four wind turbines as salient landmarks as well as from a control site without any distinctive, discrete landmark features. The GPS-recorded flight paths of the pigeons on the last training release were straighter and more similar among birds from the turbine site compared with those from the control site. The pigeons were then released from both sites following a clock-shift manipulation. Vanishing bearings from the turbine site continued to be homeward oriented as 13 of 14 pigeons returned home. By contrast, at the control site the vanishing bearings were deflected in the expected clock-shift direction and only 5 of 13 pigeons returned home. Taken together, our results offer the first strong evidence that discrete, visual landmarks are one source of spatial information homing pigeons can utilize to navigate when flying over a familiar area.

Mora CV; Ross JD; Gorsevski PV; Chowdhury B; Bingman VP

2012-10-01

228

Spectral analysis of magnetic fields from domestic appliances and corresponding induced current densities in an anatomically based model of the human head  

Energy Technology Data Exchange (ETDEWEB)

Magnetic fields emitted by electric appliances such as razors, hair dryers, and drills were measured in the frequency domain. Results show the presence of high-frequency components (up to 96 kHz for razors, up to 3.4 kHz for hair dryers, and up to 8.6 kHz for drills) in the harmonic content of the fields. The measured fields were used to calculate the induced current densities in an anatomically based model of the human head (resolution 1.31 cm) by using the impedance method. The harmonic field contribution to the current density was higher than that from the carrier frequency for all the tested appliances.

Tofani, S.; Anglesio, L.; Ossola, P.; d`Amore, G. [Servizio di Fisica Sanitaria, Ivrea (Italy)

1995-12-31

229

Anatomic Total Shoulder System  

Medline Plus

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

230

Anatomic Total Shoulder System  

Medline Plus

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

231

Anatomic Total Shoulder System  

Medline Plus

Full Text Available ... the anatomic neck starts. We're going to follow this all the way around. So that's the ... this technique with the osteotomy allows you to follow subscap healing radiographically post-op. 01:17:08 ...

232

A multi-atlas based method for automated anatomical Macaca fascicularis brain MRI segmentation and PET kinetic extraction.  

UK PubMed Central (United Kingdom)

UNLABELLED: MRI templates and digital atlases are needed for automated and reproducible quantitative analysis of non-human primate PET studies. Segmenting brain images via multiple atlases outperforms single-atlas labelling in humans. We present a set of atlases manually delineated on brain MRI scans of the monkey Macaca fascicularis. We use this multi-atlas dataset to evaluate two automated methods in terms of accuracy, robustness and reliability in segmenting brain structures on MRI and extracting regional PET measures. METHODS: Twelve individual Macaca fascicularis high-resolution 3DT1 MR images were acquired. Four individual atlases were created by manually drawing 42 anatomical structures, including cortical and sub-cortical structures, white matter regions, and ventricles. To create the MRI template, we first chose one MRI to define a reference space, and then performed a two-step iterative procedure: affine registration of individual MRIs to the reference MRI, followed by averaging of the twelve resampled MRIs. Automated segmentation in native space was obtained in two ways: 1) Maximum probability atlases were created by decision fusion of two to four individual atlases in the reference space, and transformation back into the individual native space (MAXPROB)(.) 2) One to four individual atlases were registered directly to the individual native space, and combined by decision fusion (PROPAG). Accuracy was evaluated by computing the Dice similarity index and the volume difference. The robustness and reproducibility of PET regional measurements obtained via automated segmentation was evaluated on four co-registered MRI/PET datasets, which included test-retest data. RESULTS: Dice indices were always over 0.7 and reached maximal values of 0.9 for PROPAG with all four individual atlases. There was no significant mean volume bias. The standard deviation of the bias decreased significantly when increasing the number of individual atlases. MAXPROB performed better when increasing the number of atlases used. When all four atlases were used for the MAXPROB creation, the accuracy of morphometric segmentation approached that of the PROPAG method. PET measures extracted either via automatic methods or via the manually defined regions were strongly correlated, with no significant regional differences between methods. Intra-class correlation coefficients for test-retest data were over 0.87. CONCLUSIONS: Compared to single atlas extractions, multi-atlas methods improve the accuracy of region definition. They also perform comparably to manually defined regions for PET quantification. Multiple atlases of Macaca fascicularis brains are now available and allow reproducible and simplified analyses.

Ballanger B; Tremblay L; Sgambato-Faure V; Beaudoin-Gobert M; Lavenne F; Le Bars D; Costes N

2013-08-01

233

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

International Nuclear Information System (INIS)

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

2003-01-01

234

Tracking in Anatomic Pathology.  

UK PubMed Central (United Kingdom)

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

Pantanowitz L; Mackinnon AC Jr; Sinard JH

2013-05-01

235

Algorithms to automatically quantify the geometric similarity of anatomical surfaces.  

Science.gov (United States)

We describe approaches for distances between pairs of two-dimensional surfaces (embedded in three-dimensional space) that use local structures and global information contained in interstructure geometric relationships. We present algorithms to automatically determine these distances as well as geometric correspondences. This approach is motivated by the aspiration of students of natural science to understand the continuity of form that unites the diversity of life. At present, scientists using physical traits to study evolutionary relationships among living and extinct animals analyze data extracted from carefully defined anatomical correspondence points (landmarks). Identifying and recording these landmarks is time consuming and can be done accurately only by trained morphologists. This necessity renders these studies inaccessible to nonmorphologists and causes phenomics to lag behind genomics in elucidating evolutionary patterns. Unlike other algorithms presented for morphological correspondences, our approach does not require any preliminary marking of special features or landmarks by the user. It also differs from other seminal work in computational geometry in that our algorithms are polynomial in nature and thus faster, making pairwise comparisons feasible for significantly larger numbers of digitized surfaces. We illustrate our approach using three datasets representing teeth and different bones of primates and humans, and show that it leads to highly accurate results. PMID:22025685

Boyer, Doug M; Lipman, Yaron; St Clair, Elizabeth; Puente, Jesus; Patel, Biren A; Funkhouser, Thomas; Jernvall, Jukka; Daubechies, Ingrid

2011-10-24

236

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

2007-05-01

237

Analysing intensive longitudinal data after summarization at landmarks: an application to daily pain evaluation in a clinical trial  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The paper addresses some of the key issues to be considered in analysing intensive longitudinal data after summarization at scheduled landmarks (i.e. prespecified times). In this context, the derivation of outcomes requires rigorous rules and the selection of covariates should be based on a thorough...

Bunouf, P.; Grouin, J. -M.; Molenberghs, G.; Koch, G.

238

Direct stereotactic targeting of the ventrointermediate nucleus of the thalamus based on anatomic 1.5-T MRI mapping with a white matter attenuated inversion recovery (WAIR) sequence.  

UK PubMed Central (United Kingdom)

BACKGROUND: The ventrointermediate nucleus (Vim) of the thalamus is still considered "invisible" on current magnetic resonance imaging (MRI), requiring indirect methods based on stereotactic atlases for estimation of its location. Direct visualization of Vim is desirable to improve targeting. OBJECTIVE: To evaluate the ability of Inversion-Recovery 1.5-T MR images to produce high-resolution, anatomical depiction of the thalamus suitable for direct Vim targeting. METHODS: Twenty patients with essential tremor or tremor associated with Parkinson's disease received Vim deep brain stimulation (DBS). Fahn-Tolosa-Marin and Unified Parkinson's Disease Rating Scale (UPDRS) tremor scores were assessed pre- and postoperatively. Preoperative stereotactic 1.5-T MR images of the thalamus were acquired using a White Matter Attenuated Inversion Recovery (WAIR) sequence. Thalamic nuclei were manually contoured on the basis of spontaneous MRI contrasts; labeling relied on 3D identification from stereotactic books and in-house ex vivo 4.7-T microscopic MRI atlas. Vim was then directly probed for electrophysiological confirmation and determination of the optimal site for electrode placement. RESULTS: The shape, spatial orientation, and signal contrast of Vim as depicted on our WAIR images were similar to those observed on the Schaltenbrand and Bailey atlas, as well as in our high-field MRI atlas. These images were successfully used for pure direct Vim targeting: at the last follow-up (median = 46.3 months), the average tremor score improved from 3.80 preoperatively to 0.50 postoperatively (on stimulation; P < 0.01). CONCLUSION: 1.5-T MRI with WAIR sequence provides high-quality images of Vim suitable in DBS surgery, for accurate preoperative planning, direct targeting and anatomic analysis.

Vassal F; Coste J; Derost P; Mendes V; Gabrillargues J; Nuti C; Durif F; Lemaire JJ

2012-10-01

239

Prenatal assessment of the antero-posterior jaw relationship in human fetuses: from anatomical to ultrasound cephalometric analysis.  

UK PubMed Central (United Kingdom)

Objectives : We wished to develop an ultrasound cephalometric analysis, particularly of the antero-posterior jaw relationship, to increase the accuracy of prenatal diagnosis of retrognathism during the routine midterm test. Methods : Anatomical cephalometric analysis was performed in 18 formalin-fixed human fetuses (between 16 and 39 gestational weeks), and ultrasound cephalometry was prospectively carried out in 52 pregnant women (21 to 25 gestational weeks). The same landmarks were used in the anatomical and ultrasound median sagittal planes for comparison. Four cephalometric angles were measured relative to the anterior cranial base: alveolar projection of the maxilla and the mandible, chin projection, and facial angle. The antero-posterior jaw discrepancy was calculated. Results : The projection of the maxilla was similar in the two cephalometric analyses (IC [-3.39, 0.23]), whereas the values of the projection of the mandible were lower in the ultrasound sample. The slope of the regression line of the antero-posterior jaw discrepancy on fetuses' age did not show significant differences (IC [-0.05, 1.54]) between anatomical and ultrasound cephalometry, although a difference of 3.23° ± 0.78° (IC [1.69, 4.77]) was observed. Despite this variability, the projections of mandible and chin were well determined by the projection of the maxilla both in the anatomical and ultrasound sample. Conclusions : Cephalometric analysis by prenatal sonography can be performed to study the antero-posterior jaw relationship. We think that this procedure could be useful to improve prenatal diagnosis of retrognathism in high-risk pregnancies. Further studies should address the reproducibility and accuracy of such analysis.

Captier G; Faure JM; Bäumler M; Canovas F; Demattei C; Daures JP

2011-07-01

240

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

UK PubMed Central (United Kingdom)

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

Wang L; Beyer ST; Cronk QC; Walus K

2011-01-01

 
 
 
 
241

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

Directory of Open Access Journals (Sweden)

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

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

2011-01-01

242

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

243

Object-oriented landmark recognition for UAV-navigation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Computer vision is an ever more important means for the navigation of UAVs. Here we propose a landmark recognition system looking for salient man-made infrastructure. An object-oriented structural system is preferred since it can utilize known properties of these objects such as part-of hierarchies,...

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

244

On-line SLAM using clustered landmarks with omnidirectional vision  

Scientific Electronic Library Online (English)

Full Text Available 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 inherent to the sensors. One common solution consists of establishing landmarks in the environment which are used as reference points for absolute localization estimates and form a (more) 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.

Okamoto Jr., Jun; Guizilini, Vitor Campanholo

2010-12-01

245

Pigeons combine compass and landmark guidance in familiar route navigation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

How do birds orient over familiar terrain? In the best studied avian species, the homing pigeon (Columba livia), two apparently independent primary mechanisms are currently debated: either memorized visual landmarks provide homeward guidance directly, or birds rely on a compass to home from familiar...

Biro, Dora; Freeman, Robin; Meade, Jessica; Roberts, Stephen; Guilford, Tim

246

On-line SLAM using clustered landmarks with omnidirectional vision  

Directory of Open Access Journals (Sweden)

Full Text Available The problem of SLAM (simultaneous localization and mapping) is a fundamental problem in autonomous robotics. It arises when a robot must create a map of the regions it has navigated while localizing itself on it, using results from one step to increase precision in another by eliminating errors inherent to the sensors. One common solution consists of establishing landmarks in the environment which are used as reference points for absolute localization estimates and form a sparse map that is iteratively refined as more information is obtained. This paper introduces a method of landmark selection and clustering in omnidirectional images for on-line SLAM, using the SIFT algorithm for initial feature extraction and assuming no prior knowledge of the environment. Visual sensors are an attractive way of collecting information from the environment, but tend to create an excessive amount of landmarks that are individually prone to false matches due to image noise and object similarities. By clustering several features in single objects, our approach eliminates landmarks that do not consistently represent the environment, decreasing computational cost and increasing the reliability of information incorporated. Tests conducted in real navigational situations show a significant improvement in performance without loss of quality.

Jun Okamoto Jr.; Vitor Campanholo Guizilini

2010-01-01

247

The Landmark Decision that Faded into Historical Obscurity  

Science.gov (United States)

This article takes a look at the Mendez v. Westminster School District, a landmark case that faded into historical obscurity. In the 1940s, Gonzalo and Felicita Mendez wanted their three children to attend the school nearest their farm, which was the 17th Street Elementary School in Westminster. But in the Westminster, Orange County, El Medina,…

Nance, Molly

2007-01-01

248

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

249

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

UK PubMed Central (United Kingdom)

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

Röser F; Hamburger K; Knauff M

2011-05-01

250

Is there an anatomical marker for the deep peroneal nerve in midfoot surgical approaches?  

UK PubMed Central (United Kingdom)

The deep peroneal nerve (DPN) passes over the dorsum of the foot and is susceptible to injury during surgical approaches. The purpose of this anatomical study is to examine the relationship of the extensor hallucis brevis (EHB) as it passes over the DPN. Ten cadaver feet specimens were dissected and the anatomical structures surrounding the neurovascular bundle containing the DPN were examined. In nine out of the ten specimens the DPN was under the EHB musculotendinous junction. In one case it passed through the musculotendinous junction. This cadaver study has found a consistent easily identifiable landmark for protecting the neurovascular bundle containing the DPN during dorsal midfoot surgery.

Loveday DT; Nogaro MC; Calder JD; Carmichael J

2013-04-01

251

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

252

Improving Detection Rate in Intrusion Detection Systems Using FCM Clustering to Select Meaningful Landmarks in Incremental Landmark Isomap Algorithm  

Directory of Open Access Journals (Sweden)

Full Text Available Dimension reduction is crucial when it is applied on intrusion detection systems. Many data mining algorithms have been used for this purpose. For example, manifold learning algorithms, especially Isometric feature mapping (Isomap) have been investigated. Researchers successfully applied Isomap on intrusion detection system as a nonlinear dimension reduction method. But it had some problems such as operation on batch mode and being disabled to handle new data points, additionally, it had computational cost and could not be properly applied on huge datasets. Losing time and reducing speed of detection is another problem of Isomap in intrusion detection systems. Incremental Landmark Isomap which selects landmarks among whole data points has been invented for solving these problems. In this paper, we use FCM as a data reduction method to select meaningful landmarks for Incremental L-Isomap instead of choosing them randomly. This method is implemented and applied on some UCI datasets and also NSLKDD dataset. The results demonstrate higher detection rate for the proposed method, comparing to classical Incremental L-Isomap which chooses landmarks randomly.

Seyed Mehdi Iranmanesh; Mehdi Mohammadi; Ahmad Akbari; Babak Nassersharif

2012-01-01

253

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 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 Santiago en el Servicio de Cirugía Plástica desde enero de 2008 hasta diciembre de 2010. Se reclutaron a un total de 15 pacientes, 13 (87%) de los cuales eran unilatera (more) les 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 and Methods: Retrospective study of patients treated at two plastic surgery departments from January 2008 to December 2010. We recruited a total of 15 patients aged 9 to 25 years (more) . 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.

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

2012-12-01

254

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 ...

255

Anatomical Global Spatial Normalization  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Anatomical global spatial normalization (aGSN) is presented as a method to scale high-resolution brain images to control for variability in brain size without altering the mean size of other brain structures. Two types of mean preserving scaling methods were investigated, “shape preserving” and “sha...

Lancaster, Jack L.; Cykowski, Matthew D.; McKay, David Reese; Kochunov, Peter V.; Fox, Peter T.; Rogers, William

256

Development of IDL-based software for multimodal image registration  

Energy Technology Data Exchange (ETDEWEB)

Image registration with anatomical modalities such as CT and MRI, facilitates the anatomical localization in the interpretation of nuclear medicine images, which are relatively lacking in anatomical information. User-friendly program for image registration and fusion of registered images was developed. In consideration of easy transplantation to various operating systems (OS), the program was developed using IDL language. For the registration without operator's interaction, several automatic algorithms were implemented, which include principal axes matching and maximization of mutual information methods. User interface was designed to support the manual registration using point landmarks and the correction for unwanted mis-registration. Fused images were composed by overlaying one image with the other one transparently, in which the opacity of overlaid image was interactively controlled. OS and platform independent program for image registration was developed based on IDL language. It will be useful for the clinical application of image registration techniques.

Lee, Jae Sung; Park, Kwang Suk; Lee, Dong Soo; Chung, June Key; Lee, Myung Chul [College of Medicine, Seoul National Univ., Seoul (Korea, Republic of)

2001-07-01

257

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

Science.gov (United States)

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

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

2010-03-01

258

[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

259

Transcatheter aortic valve implantation using anatomically oriented, marrow stromal cell-based, stented, tissue-engineered heart valves: technical considerations and implications for translational cell-based heart valve concepts.  

Science.gov (United States)

OBJECTIVES: While transcatheter aortic valve implantation (TAVI) has rapidly evolved for the treatment of aortic valve disease, the currently used bioprostheses are prone to continuous calcific degeneration. Thus, autologous, cell-based, living, tissue-engineered heart valves (TEHVs) with regeneration potential have been suggested to overcome these limitations. We investigate the technical feasibility of combining the concept of TEHV with transapical implantation technology using a state-of-the-art transcatheter delivery system facilitating the exact anatomical position in the systemic circulation. METHODS: Trileaflet TEHVs fabricated from biodegradable synthetic scaffolds were sewn onto self-expanding Nitinol stents seeded with autologous marrow stromal cells, crimped and transapically delivered into the orthotopic aortic valve position of adult sheep (n = 4) using the JenaValve transapical TAVI System (JenaValve, Munich, Germany). Delivery, positioning and functionality were assessed by angiography and echocardiography before the TEHV underwent post-mortem gross examination. For three-dimensional reconstruction of the stent position of the anatomically oriented system, a computed tomography analysis was performed post-mortem. RESULTS: Anatomically oriented, transapical delivery of marrow stromal cell-based TEHV into the orthotopic aortic valve position was successful in all animals (n = 4), with a duration from cell harvest to TEHV implantation of 101 ± 6 min. Fluoroscopy and echocardiography displayed sufficient positioning, thereby entirely excluding the native leaflets. There were no signs of coronary obstruction. All TEHV tolerated the loading pressure of the systemic circulation and no acute ruptures occurred. Animals displayed intact and mobile leaflets with an adequate functionality. The mean transvalvular gradient was 7.8 ± 0.9 mmHg, and the mean effective orifice area was 1.73 ± 0.02 cm². Paravalvular leakage was present in two animals, and central aortic regurgitation due to a single-leaflet prolapse was detected in two, which was primarily related to the leaflet design. No stent dislocation, migration or affection of the mitral valve was observed. CONCLUSIONS: For the first time, we demonstrate the technical feasibility of a transapical TEHV delivery into the aortic valve position using a commercially available and clinically applied transapical implantation system that allows for exact anatomical positioning. Our data indicate that the combination of TEHV and a state-of-the-art transapical delivery system is feasible, representing an important step towards translational, transcatheter-based TEHV concepts. PMID:23657551

Emmert, Maximilian Y; Weber, Benedikt; Behr, Luc; Sammut, Sebastien; Frauenfelder, Thomas; Wolint, Petra; Scherman, Jacques; Bettex, Dominique; Grünenfelder, Jürg; Falk, Volkmar; Hoerstrup, Simon P

2013-05-01

260

Transcatheter aortic valve implantation using anatomically oriented, marrow stromal cell-based, stented, tissue-engineered heart valves: technical considerations and implications for translational cell-based heart valve concepts.  

UK PubMed Central (United Kingdom)

OBJECTIVES: While transcatheter aortic valve implantation (TAVI) has rapidly evolved for the treatment of aortic valve disease, the currently used bioprostheses are prone to continuous calcific degeneration. Thus, autologous, cell-based, living, tissue-engineered heart valves (TEHVs) with regeneration potential have been suggested to overcome these limitations. We investigate the technical feasibility of combining the concept of TEHV with transapical implantation technology using a state-of-the-art transcatheter delivery system facilitating the exact anatomical position in the systemic circulation. METHODS: Trileaflet TEHVs fabricated from biodegradable synthetic scaffolds were sewn onto self-expanding Nitinol stents seeded with autologous marrow stromal cells, crimped and transapically delivered into the orthotopic aortic valve position of adult sheep (n = 4) using the JenaValve transapical TAVI System (JenaValve, Munich, Germany). Delivery, positioning and functionality were assessed by angiography and echocardiography before the TEHV underwent post-mortem gross examination. For three-dimensional reconstruction of the stent position of the anatomically oriented system, a computed tomography analysis was performed post-mortem. RESULTS: Anatomically oriented, transapical delivery of marrow stromal cell-based TEHV into the orthotopic aortic valve position was successful in all animals (n = 4), with a duration from cell harvest to TEHV implantation of 101 ± 6 min. Fluoroscopy and echocardiography displayed sufficient positioning, thereby entirely excluding the native leaflets. There were no signs of coronary obstruction. All TEHV tolerated the loading pressure of the systemic circulation and no acute ruptures occurred. Animals displayed intact and mobile leaflets with an adequate functionality. The mean transvalvular gradient was 7.8 ± 0.9 mmHg, and the mean effective orifice area was 1.73 ± 0.02 cm². Paravalvular leakage was present in two animals, and central aortic regurgitation due to a single-leaflet prolapse was detected in two, which was primarily related to the leaflet design. No stent dislocation, migration or affection of the mitral valve was observed. CONCLUSIONS: For the first time, we demonstrate the technical feasibility of a transapical TEHV delivery into the aortic valve position using a commercially available and clinically applied transapical implantation system that allows for exact anatomical positioning. Our data indicate that the combination of TEHV and a state-of-the-art transapical delivery system is feasible, representing an important step towards translational, transcatheter-based TEHV concepts.

Emmert MY; Weber B; Behr L; Sammut S; Frauenfelder T; Wolint P; Scherman J; Bettex D; Grünenfelder J; Falk V; Hoerstrup SP

2013-05-01

 
 
 
 
261

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

DEFF Research Database (Denmark)

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

Goranko, Valentin

2012-01-01

262

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

2012-10-18

263

Dung beetles ignore landmarks for straight-line orientation.  

UK PubMed Central (United Kingdom)

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.

Dacke M; Byrne M; Smolka J; Warrant E; Baird E

2013-01-01

264

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

265

AUGMENTED INLINE-BASED NAVIGATION FOR STEREOTACTIC IMAGE GUIDED NEUROSURGERY  

Science.gov (United States)

Image-guided neurosurgery requires navigation in 3D using a computer-assisted surgery system that tracks surgical tools in realtime and displays their positions with respect to the preoperatively acquired images (e.g. CT, MRI, fMRI etc.) A key problem in image guided procedures is the need to navigate to specific locations highlighted in the images, such as image-derived functional areas, that have no obvious corresponding anatomical landmarks – we refer to such locations as virtual landmarks. To address these issues, we contribute a novel interactive visualization technique to provide improved feedback to surgeons - Augmented inline visualization. Based on the results of an expert evaluation, we found neurosurgeons to be 30% more accurate when using our augmented inline representation.

Joshi, A; Scheinost, D; Globinsky, R; Vives, K. P.; Spencer, D. D.; Staib, L. H.; Papademetris, X

2011-01-01

266

Experience in Aligning Anatomical Ontologies.  

Science.gov (United States)

An ontology is a formal representation of a domain modeling the entities in the domain and their relations. When a domain is represented by multiple ontologies, there is need for creating mappings among these ontologies in order to facilitate the integration of data annotated with these ontologies and reasoning across ontologies. The objective of this paper is to recapitulate our experience in aligning large anatomical ontologies and to reflect on some of the issues and challenges encountered along the way. The four anatomical ontologies under investigation are the Foundational Model of Anatomy, GALEN, the Adult Mouse Anatomical Dictionary and the NCI Thesaurus. Their underlying representation formalisms are all different. Our approach to aligning concepts (directly) is automatic, rule-based, and operates at the schema level, generating mostly point-to-point mappings. It uses a combination of domain-specific lexical techniques and structural and semantic techniques (to validate the mappings suggested lexically). It also takes advantage of domain-specific knowledge (lexical knowledge from external resources such as the Unified Medical Language System, as well as knowledge augmentation and inference techniques). In addition to point-to-point mapping of concepts, we present the alignment of relationships and the mapping of concepts group-to-group. We have also successfully tested an indirect alignment through a domain-specific reference ontology. We present an evaluation of our techniques, both against a gold standard established manually and against a generic schema matching system. The advantages and limitations of our approach are analyzed and discussed throughout the paper. PMID:18974854

Zhang, Songmao; Bodenreider, Olivier

2007-01-01

267

Experience in Aligning Anatomical Ontologies.  

UK PubMed Central (United Kingdom)

An ontology is a formal representation of a domain modeling the entities in the domain and their relations. When a domain is represented by multiple ontologies, there is need for creating mappings among these ontologies in order to facilitate the integration of data annotated with these ontologies and reasoning across ontologies. The objective of this paper is to recapitulate our experience in aligning large anatomical ontologies and to reflect on some of the issues and challenges encountered along the way. The four anatomical ontologies under investigation are the Foundational Model of Anatomy, GALEN, the Adult Mouse Anatomical Dictionary and the NCI Thesaurus. Their underlying representation formalisms are all different. Our approach to aligning concepts (directly) is automatic, rule-based, and operates at the schema level, generating mostly point-to-point mappings. It uses a combination of domain-specific lexical techniques and structural and semantic techniques (to validate the mappings suggested lexically). It also takes advantage of domain-specific knowledge (lexical knowledge from external resources such as the Unified Medical Language System, as well as knowledge augmentation and inference techniques). In addition to point-to-point mapping of concepts, we present the alignment of relationships and the mapping of concepts group-to-group. We have also successfully tested an indirect alignment through a domain-specific reference ontology. We present an evaluation of our techniques, both against a gold standard established manually and against a generic schema matching system. The advantages and limitations of our approach are analyzed and discussed throughout the paper.

Zhang S; Bodenreider O

2007-01-01

268

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.)

2005-01-01

269

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 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 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 variaçõ (more) es 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 cervi (more) cal 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.

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

2006-06-01

270

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; Mangala M. Pai; Latha V. Prabhu; Sujatha D'Costa; Prakash Shetty

2006-01-01

271

Anatomical study of sacral hiatus for successful caudal epidural block  

Directory of Open Access Journals (Sweden)

Full Text Available Present study determined the landmarks for caudal epidural block (CEB) after morphometric measurements of the sacral hiatus on dry sacral bones. The CEB has been widely used procedure for the diagnosis and treatment of lumbar spinal disorders. Anatomical features of the sacral hiatus and the detailed knowledge about sacral hiatus. Materials & Methods: 116 sacral bones are used for the study. Anatomical measurements were measured by using vernier caliper accuracy to 0.1 mm. Results: Agenesis of sacral hiatus was detected in two sacral bones. Various shapes of sacral hiatus were observed which included inverted U (31%), inverted V (25.8%), irregular (20.6%), Elongated (17.2%) and dumbbell (5%). Apex of sacral hiatus was commonly found at the level of 4th sacral vertebra in 50.8%. The distance between the two supero lateral sacral crests and the distance between the apex of sacral hiatus and the right and left supero lateral crests were 69.5 (5.8) mm, 61.4 (11.2) mm, 57.4 (9.7) mm respectively, on average. The mean, mode, SD is calculated for all the measurements. Conclusion: The sacral hiatus has anatomic variations. Understanding of these variations may improve the reliability of CEB.

Ramamurthi KS, Anilkumar Reddy Y

2013-01-01

272

The post-birthday world: consequences of temporal landmarks for temporal self-appraisal and motivation.  

UK PubMed Central (United Kingdom)

Much as physical landmarks help structure our representation of space, temporal landmarks such as birthdays and significant calendar dates structure our perception of time, such that people may organize or categorize their lives into "chunks" separated by these markers. Categories on the temporal landscape may vary depending on what landmarks are salient at a given time. We suggest these landmarks have implications for identity and motivation. The present research examined consequences of salient temporal landmarks for perceptions of the self across time and motivation to pursue successful future selves. Studies 1 and 2 show that temporally extended selves are perceived as less connected to, and more dissimilar from, the current self when an intervening landmark event has been made salient. Study 3 addresses the proposed mechanism, demonstrating that intervening landmarks lead people to categorize pre- and postlandmark selves into separate categories more often than when the same time period contains no salient landmarks. Finally, we examined whether landmark-induced mental contrasting of present state and future desired state could increase goal-pursuit motivation (in an effort to bridge the gap between inferior present and better future states). Studies 4-6 demonstrate that landmark-induced discrepancies between current health and hoped-for future health increased participants' motivation to exercise and increased the likelihood that they acted in line with their future-oriented goals.

Peetz J; Wilson AE

2013-02-01

273

Anatomic Hemispherectomy: Historical Perspective.  

Science.gov (United States)

The history of surgical treatment for hemispheric epilepsy is rich with colorful twists and turns. The authors trace the evolution of the surgical treatment of hemispheric epilepsy from radical anatomic resections to current less invasive disconnection procedures. Anatomic hemispherectomy (AH) was first described by Dandy in 1928 as a treatment for gliomas. The first report of this technique to control seizures was by McKenzie in 1938. AH gained wide popularity but began to fall out of favor after the description of superficial cerebral hemosiderosis in 1966. To reduce the morbidity and mortality associated with AH, Rasmussen introduced functional hemispherectomy in 1974. The technique of hemispherotomy was introduced in the 1990s to minimize the extent of brain removal while maximizing the white matter disconnections. Thus, surgery for hemispheric epilepsy has undergone dramatic transformation since the technique was first introduced. Less invasive techniques have been developed to reduce surgical morbidity. Although optimal seizure control is best achieved with radical AH, the newer less invasive disconnection techniques appear to achieve near-comparable postoperative seizure control with a significantly lower rate of complications. PMID:22480976

Bahuleyan, Biji; Robinson, Shenandoah; Nair, Ajith Rajappan; Sivanandapanicker, Jyothish L; Cohen, Alan R

2012-04-01

274

Landmark trials affecting the surgical management of invasive breast cancer.  

UK PubMed Central (United Kingdom)

Significant progress has been made in the surgical management of breast cancer. Most women diagnosed with early stage invasive breast cancer can now be managed with breast-conserving therapy to include a segmental mastectomy followed by radiation. Axillary lymph nodes are routinely assessed by sentinel lymph node biopsy. Axillary lymph node dissection is reserved for patients with documented nodal metastasis; however, here too progress has been made because a population of low-risk patients has been identified in whom a complete dissection is not required even in the setting of a positive sentinel lymph node. This article details the landmark clinical trials that have guided the surgical management of breast cancer.

Black DM; Mittendorf EA

2013-04-01

275

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

Directory of Open Access Journals (Sweden)

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; Flavio Prieto

2010-01-01

276

Vaginal malformations: a proposed classification based on embryological, anatomical and clinical criteria and their surgical management (an analysis of 167 cases).  

UK PubMed Central (United Kingdom)

BACKGROUND: Although it is virtually impossible to formulate a scheme that can satisfactorily collect all different types of vaginal malformations, a simple classification would be of a considerable value and would permit logical operative decisions. Many classifications of anomalies of uterus and vagina have been proposed: we find them unsatisfactory and confusing, being either too simple or too complex. We propose a new classification, focused only on vagina and based on embryological, anatomical, clinical and surgical criteria. METHODS: In over 30 years, 167 females with vaginal malformations have been observed in our department. Intersex cases were excluded. The encountered anomalies have been divided into six types and ten subtypes: type I vaginal agenesis (IA associated with uterine agenesis/17 Pts, IB isolated/1 Pt); type II vaginal atresia (IIA proximal/1 Pt, IIB distal/4 Pts); type III vaginal atresia with urethrovaginal fistula-urogenital sinus (IIIA proximal fistula-high sinus/42 Pts, IIIB distal fistula-low sinus/55 Pts); type IV vaginal atresia with transverse septum (IVA transverse septum/6 Pts, IVB imperforate hymen/17 Pts); type V disorders of müllerian ducts fusion (VA vaginal duplication/4 Pts, VB longitudinal septum/4 Pts); type VI cloaca/16 Pts. Of each type and subgroup of malformation the appropriate surgical correction is reported. Types of malformation and surgical treatment are analysed: IA vaginal reconstruction using a sigmoid conduit, IB vaginal reconstruction using a sigmoid conduit, atresic cervical resection and uterus-new vagina anastomosis according to Schmid; II perineal vaginal pull-through; IIIA anterior sagittal transanorectal vaginal pull-through, IIIB perineal flap vaginoplasty; IVA excision with abdominovaginal approach, IVB hymen incision; VA tubularization, VB septectomy via perineal approach; VI posterior sagittal anorectal-vaginal-urethroplasty. RESULTS: Most of the patients had good aesthetic and functional results. Type III showed relatively more complications: four redo operations (IIIA), four revisions of the vaginoplasty (IIIB). One patient is still waiting for definitive surgical correction. CONCLUSIONS: An early diagnosis is desirable to correct adequately vaginal malformations, which becomes mostly evident around puberty. The better timing for surgery is early age, to obtain better results and to avoid many of the psychological problems that arise at a later age.

Ruggeri G; Gargano T; Antonellini C; Carlini V; Randi B; Destro F; Lima M

2012-08-01

277

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)

[en] 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

2008-01-01

278

Slice-based supine-to-standing posture deformation for Chinese anatomical models and the dosimetricresults with wide band frequency electromagnetic field exposure: simulation.  

UK PubMed Central (United Kingdom)

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.

Wu T; Tan L; Shao Q; Li Y; Yang L; Zhao C; Xie Y; Zhang S

2013-04-01

279

Dominance of the odometer over serial landmark learning in honeybee navigation  

Science.gov (United States)

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

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

2010-08-01

280

Do individuals with intellectual disability select appropriate objects as landmarks when learning a new route?  

UK PubMed Central (United Kingdom)

BACKGROUND: The present study was aimed at investigating the selection of landmarks by individuals with intellectual disability (ID). The hypothesis was that they would be less efficient than individuals without IDs in the selection of landmarks when learning a new route. METHODS: The experiment took place in a natural setting with a group of participants with ID and a group of control participants matched by chronological age. The participants were first guided along a route situated in an unfamiliar district. Then, they had to guide the experimenter along the route while pointing to all the objects and features they found useful for wayfinding. RESULTS: The designated objects were categorised as a function of their landmarks properties. There were significant differences between the two groups for non-permanent landmarks, distant landmarks and non-unique landmarks. The two groups selected landmarks near intersections in the same proportions. However, the individuals with ID selected more non-unique landmarks and less textual signage than the control group at these decision points. CONCLUSION: Individuals with ID seem to be less efficient than individuals without disability in landmark selection. This may limit their wayfinding abilities in their day-to-day travelling. This may also account for their difficulties in obtaining the kind of spatial knowledge which relates to the configural structure of their environment.

Courbois Y; Blades M; Farran EK; Sockeel P

2013-01-01

 
 
 
 
281

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Component position is critical to longevity of knee arthroplasties. Femoral component rotation is typically referenced from the transepicondylar axis (TEA), the anterior-posterior (AP) axis or the posterior condylar axis. Other studies have shown high variability in locating the TEA while proposing ...

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

282

Anatomical study for SLAP lesion repair.  

UK PubMed Central (United Kingdom)

PURPOSE: The purpose of this study was to meticulously observe the structures around the origin of the long head of the biceps tendon (LHB) in order to propose a method of anatomical superior labrum anterior and posterior repair. METHODS: Twenty-eight shoulders of 16 cadavers with intact LHB origin were macroscopically investigated. Among them, 20 shoulders with an intact superior labrum were additionally observed, to determine whether the anterior edge of LHB on the labrum (point 'A') was anterior to the supraglenoid tubercle. Serial sections vertical to LHB were observed using ordinary light and polarized microscopy in three glenoids and scanning acoustic microscopy in one. RESULTS: The labrum had a meniscal appearance, and no LHB fibre was sent anterior to the anterior edge of the supraglenoid tubercle. 'A' was not located more posterior than the supraglenoid tubercle. All specimens had the so-called 'the sheet-like structure', in which the portion closer to the LHB origin tends to be stiffer. Fibres of the sheet-like structure ran vertically to LHB. CONCLUSION: Fibre orientation and the stiffness of the sheet-like structure suggest its support of LHB. As LHB fibres do not anteriorly cross over 'A', 'A' could be a landmark for the anterior border of LHB, independent from the sheet-like structure. Considering a previous report mentioning that the horizontal mattress suture maintains the meniscus-like structure which might be sufficient for proper motion of the normal superior labrum, the horizontal mattress suture not crossing over 'A' should be recommended from the viewpoint of functional anatomy.

Arai R; Kobayashi M; Harada H; Tsukiyama H; Saji T; Toda Y; Hagiwara Y; Miura T; Matsuda S

2013-01-01

283

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

Directory of Open Access Journals (Sweden)

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

2010-01-01

284

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

UK PubMed Central (United Kingdom)

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

Kettunen P; Irvankoski K; Krause CM; Sarjakoski LT

2013-08-01

285

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; Chiriva-Internati Maurizio

2005-01-01

286

Recent advances in standards for collaborative Digital Anatomic Pathology  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Context Collaborative Digital Anatomic Pathology refers to the use of information technology that supports the creation and sharing or exchange of information, including data and images, during the complex workflow performed in an Anatomic Pathology department from specimen reception to report transmission and exploitation. Collaborative Digital Anatomic Pathology can only be fully achieved using medical informatics standards. The goal of the international integrating the Healthcare Enterprise (IHE) initiative is precisely specifying how medical informatics standards should be implemented to meet specific health care needs and making systems integration more efficient and less expensive. Objective To define the best use of medical informatics standards in order to share and exchange machine-readable structured reports and their evidences (including whole slide images) within hospitals and across healthcare facilities. Methods Specific working groups dedicated to Anatomy Pathology within multiple standards organizations defined standard-based data structures for Anatomic Pathology reports and images as well as informatic transactions in order to integrate Anatomic Pathology information into the electronic healthcare enterprise. Results The DICOM supplements 122 and 145 provide flexible object information definitions dedicated respectively to specimen description and Whole Slide Image acquisition, storage and display. The content profile “Anatomic Pathology Structured Report” (APSR) provides standard templates for structured reports in which textual observations may be bound to digital images or regions of interest. Anatomic Pathology observations are encoded using an international controlled vocabulary defined by the IHE Anatomic Pathology domain that is currently being mapped to SNOMED CT concepts. Conclusion Recent advances in standards for Collaborative Digital Anatomic Pathology are a unique opportunity to share or exchange Anatomic Pathology structured reports that are interoperable at an international level. The use of machine-readable format of APSR supports the development of decision support as well as secondary use of Anatomic Pathology information for epidemiology or clinical research.

Daniel Christel; Macary François; García Rojo Marcial; Klossa Jacques; Laurinavi?ius Arvydas; Beckwith Bruce A; Della Mea Vincenzo

2011-01-01

287

Anatomical Variations of the Flexor Hallucis Longus and Flexor Digitorum Longus in the Chiasma Plantare.  

UK PubMed Central (United Kingdom)

BACKGROUND: The flexor hallucis longus (FHL) and flexor digitorum longus (FDL) tendon are routinely used in reconstructive foot and ankle surgery. The tendons cross in the chiasma plantare and show variable interconnections. This can complicate harvesting of the tendons. Previous anatomical studies were inconclusive and did not reference the connections to surgically relevant landmarks. The purpose of this study was to integrate these conflicting results, introduce a thorough classification system, and analyze the position of the interconnections relative to the surgically relevant bone landmarks. METHODS: Sixty embalmed feet of 30 cadavers were analyzed anatomically with respect to the individual cross-links in the planta pedis. All feet were photo documented. The interconnections were classified in a modified classification system and distances to surgically relevant anatomic landmarks measured. RESULTS: A proximal to distal connection from the FHL to the FDL was found in 95% of the feet (types I and III), in 3% there was a proximal to distal connection from the FDL to the FHL (type II) tendon only, and in 30% a crossed connection (type III) was found. The average point of branching of the FHL and FDL tendon was 5.3 and 4.6 cm distal to the medial malleolus, respectively. CONCLUSION: Our modified classification system accommodated all found variations. In over 90% of the feet, a proximal to distal connection from the FHL to the FDL was found, which might contribute to the residual function of the lesser toes after FDL transfer. CLINICAL RELEVANCE: The exact knowledge of the anatomy of the crossing of FDL and FHL in the plantar foot is essential to facilitate tendon harvesting, reduce morbidity and explain possible postoperative functional loss.

Plaass C; Abuharbid G; Waizy H; Ochs M; Stukenborg-Colsman C; Schmiedl A

2013-06-01

288

A neural wayfinding mechanism adjusts for ambiguous landmark information.  

UK PubMed Central (United Kingdom)

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

Janzen G; Jansen C

2010-08-01

289

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

Directory of Open Access Journals (Sweden)

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

Rosalia Leonardi; Daniela Giordano; Francesco Maiorana

2009-01-01

290

Incorporating Anatomical Side Information Into PET Reconstruction Using Nonlocal Regularization.  

UK PubMed Central (United Kingdom)

With the introduction of combined positron emission tomography (PET)/computed tomography (CT) or PET/magnetic resonance imaging (MRI) scanners, there is an increasing emphasis on reconstructing PET images with the aid of the anatomical side information obtained from X-ray CT or MRI scanners. In this paper, we propose a new approach to incorporating prior anatomical information into PET reconstruction using the nonlocal regularization method. The nonlocal regularizer developed for this application is designed to selectively consider the anatomical information only when it is reliable. As our proposed nonlocal regularization method does not directly use anatomical edges or boundaries which are often used in conventional methods, it is not only free from additional processes to extract anatomical boundaries or segmented regions, but also more robust to the signal mismatch problem that is caused by the indirect relationship between the PET image and the anatomical image. We perform simulations with digital phantoms. According to our experimental results, compared to the conventional method based on the traditional local regularization method, our nonlocal regularization method performs well even with the imperfect prior anatomical information or in the presence of signal mismatch between the PET image and the anatomical image.

Nguyen VG; Lee SJ

2013-10-01

291

Axial MR imaging of the internal structures of the brain stem with anatomic and pathologic correlation  

International Nuclear Information System (INIS)

This exhibit displays the detailed internal anatomy of the brain stem in the axial plane as seen with high-resolution, high-field (1.5 T) MR imaging. The authors correlate the MR images with cadaver anatomic sections and extensive diagrams at multiple levels. By using external surface landmarks and the visible internal structures, one is able to approximate many of the small nuclei and tracts of the brain stem. Correlation of individual lesions with clinical symptoms is made. Examples of pathology including tumors, arteriovenous malformations, demyelinating disorders, and congenital malformations are shown

1987-12-04

292

A multi-segment foot model based on anatomically registered technical coordinate systems: method repeatability and sensitivity in pediatric planovalgus feet.  

UK PubMed Central (United Kingdom)

Several multisegment foot models have been proposed and some have been used to study foot pathologies. These models have been tested and validated on typically developed populations; however application of such models to feet with significant deformities presents an additional set of challenges. For the first time, in this study, a multisegment foot model is tested for repeatability in a population of children with symptomatic abnormal feet. The results from this population are compared to the same metrics collected from an age matched (8-14 years) typically developing population. The modified Shriners Hospitals for Children, Greenville (mSHCG) foot model was applied to ten typically developing children and eleven children with planovalgus feet by two clinicians. Five subjects in each group were retested by both clinicians after 4-6 weeks. Both intra-clinician and inter-clinician repeatability were evaluated using static and dynamic measures. A plaster mold method was used to quantify variability arising from marker placement error. Dynamic variability was measured by examining trial differences from the same subjects when multiple clinicians carried out the data collection multiple times. For hindfoot and forefoot angles, static and dynamic variability in both groups was found to be less than 4° and 6° respectively. The mSHCG model strategy of minimal reliance on anatomical markers for dynamic measures and inherent flexibility enabled by separate anatomical and technical coordinate systems resulted in a model equally repeatable in typically developing and planovalgus populations.

Saraswat P; MacWilliams BA; Davis RB; D'Astous JL

2013-01-01

293

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

Energy Technology Data Exchange (ETDEWEB)

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

294

Review of the Historical Evolution of Anatomical Terms  

Directory of Open Access Journals (Sweden)

Full Text Available Most of the medical terms of Greek origin are traditionally attributed to Hippocrates (460-370 BC). Claudius Galen of Pergamum (130-200 BC) developed a classification of bones and joints and described different brain areas. His teachings have remained unchanged for over a thousand years. Andreas Vesalius of Brussels (1514-1564), through the systematic study of human body structure, changed many concepts. He published his work in his production "De humani corporis fabrica libri septem", where a special attention is evident to the discovery and description of new anatomical facts. From here there is a revolution in the morphological sciences, where the same anatomical structure passed to receive different names. In the nineteenth century, the different anatomists in the world decide to meet in order to unify criteria regarding the anatomical structures and determine a only one universal language in the anatomical sciences. In 1895, in Basel (Switzerland) it’s approved a list of 5.573 terms, called Basle Nomina Anatomica (BNA) and was written in Latin. Eponyms were deleted. In 1903, he founded the International Federation of Associations of anatomists (IFAA). In 1935, in Jena (Germany), approving the Jena Nomina Anatomica (JNA). In 1950, in Oxford, formed the Committee of the International Anatomical Nomenclature (IANC). In 1955, in Paris (France) it is agreed to adopt a Latin nomenclature based on the BNA, the Paris Nomina Anatomica (PNA). In 1980, for the first time in Latin America, takes place on the 11th International Congress of Anatomists, Mexico. In 1989, the International Committee of Anatomical Nomenclature, published the sixth edition of the Nomina Anatomica, without review by the IFAA. The same year, the latter established a Federative International Committee of Anatomical Terminology (FICAT). In 1998, he published a new list FICAT: International Anatomical Terminology (TAI), with the structures named in Latin language and their equivalence in English, listing which updates and supersedes all previous nomenclatures. In September 2001, the Spanish Anatomical Society translated this International Anatomical Terminology into Spanish language.The study of the historical backgrounds in the worldwide development of Anatomical Terms, give us valuable data about the origin and foundation of the names. It is necessary to raise awareness about the implementation of a unified, updated and uniform anatomical terminology, when conducting scientific communications and publications. As specialists in this discipline, we must study and know the existence of the official list of anatomical terms of use worldwide (International Anatomical Terminology), its equivalence with previous classifications, keeping us updated about its changes to teach it to new generations of health professionals.

Algieri, Rubén D.; Pró, Eduardo A.; Forlizzi, Valeria; Ferrante, María Soledad

2011-01-01

295

Anatomical education and surgical simulation based on the Chinese Visible Human: a three-dimensional virtual model of the larynx region.  

UK PubMed Central (United Kingdom)

Anatomical knowledge of the larynx region is critical for understanding laryngeal disease and performing required interventions. Virtual reality is a useful method for surgical education and simulation. Here, we assembled segmented cross-section slices of the larynx region from the Chinese Visible Human dataset. The laryngeal structures were precisely segmented manually as 2D images, then reconstructed and displayed as 3D images in the virtual reality Dextrobeam system. Using visualization and interaction with the virtual reality modeling language model, a digital laryngeal anatomy instruction was constructed using HTML and JavaScript languages. The volume larynx models can thus display an arbitrary section of the model and provide a virtual dissection function. This networked teaching system of the digital laryngeal anatomy can be read remotely, displayed locally, and manipulated interactively.

Liu K; Fang B; Wu Y; Li Y; Jin J; Tan L; Zhang S

2013-09-01

296

Anatomic and CT scan assessment of Teres Minor: a new index of trophicity.  

UK PubMed Central (United Kingdom)

INTRODUCTION: The present study reports the development of a CT assessment protocol for Teres Minor (TM) trophicity. HYPOTHESIS: Quantitative reproductible Terres Minor assessment on CT estimates the influence of muscle trophicity on the clinical and radiological results of palliative treatment of irreparable rotator cuff tear. MATERIALS AND METHOD: An anatomic study of 30 cadaveric shoulders confirmed a constant anatomic relation between Terres Minor and the inferior pole of the glenoid cavity. This landmark was used to develop a novel CT assessment of TM trophicity. RESULTS: The CT assessment showed excellent inter- and intra-observer reproductibility. The protocol defines a trophicity index, T2/G (T2 being TM thickness on axial CT slice, and G the maximum glenoid cavity thickness on axial slice), enabling reproductible TM analysis on preoperative arthro-CT. CONCLUSION: The study validated the CT protocol, allowing application in pre- and postoperative assessment of irreparable rotator cuff tear. LEVEL OF EVIDENCE: Level IV. Retrospective study.

Szymanski C; Boniface O; Demondion X; Deladerrière JY; Vervoort T; Cotten A; Maynou C

2013-06-01

297

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

Directory of Open Access Journals (Sweden)

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; Fatma Nur Kaya; Alp Gurbet; Hale Aksu; Cuneyt Erdogan; Ahmet Atlas

2009-01-01

298

Anatomical targeting in functional neurosurgery by the simultaneous use of multiple Schaltenbrand-Wahren brain atlas microseries.  

Science.gov (United States)

This paper presents a novel approach for the use of the Atlas for Stereotaxy of the Human Brain by Schaltenbrand and Wahren [Stuttgart, Thieme, 1977] for anatomical targeting in functional neurosurgery. We propose to use simultaneously all three electronic axial, coronal and sagittal mutually coregistered Schaltenbrand-Wahren brain atlas microseries. The printed atlas microseries are digitized, extended to cover both hemispheres, contoured, labeled, organized into atlas volumes, and mutually coregistered. The electronic atlas is interactively registered with the data by using the three-dimensional Talairach proportional grid system transformation, followed up by local warping in the region of interest based on any clearly visible landmarks. The detailed targeting steps for pallidotomy, thalamotomy and subthalamotomy are formulated. The potential of this approach is to increase the accuracy of target definition, to decrease the time of the procedure by reducing the number of microelectrode tracts, and to give an extra degree of confidence to the neurosurgeon. The advantages of the approach and the limitations of the Schaltenbrand-Wahren atlas are discussed. PMID:10420144

Nowinski, W L

1998-01-01

299

Anatomical targeting in functional neurosurgery by the simultaneous use of multiple Schaltenbrand-Wahren brain atlas microseries.  

UK PubMed Central (United Kingdom)

This paper presents a novel approach for the use of the Atlas for Stereotaxy of the Human Brain by Schaltenbrand and Wahren [Stuttgart, Thieme, 1977] for anatomical targeting in functional neurosurgery. We propose to use simultaneously all three electronic axial, coronal and sagittal mutually coregistered Schaltenbrand-Wahren brain atlas microseries. The printed atlas microseries are digitized, extended to cover both hemispheres, contoured, labeled, organized into atlas volumes, and mutually coregistered. The electronic atlas is interactively registered with the data by using the three-dimensional Talairach proportional grid system transformation, followed up by local warping in the region of interest based on any clearly visible landmarks. The detailed targeting steps for pallidotomy, thalamotomy and subthalamotomy are formulated. The potential of this approach is to increase the accuracy of target definition, to decrease the time of the procedure by reducing the number of microelectrode tracts, and to give an extra degree of confidence to the neurosurgeon. The advantages of the approach and the limitations of the Schaltenbrand-Wahren atlas are discussed.

Nowinski WL

1998-01-01

300

Reproducibility of facial soft tissue landmarks on facial images captured on a 3D camera.  

UK PubMed Central (United Kingdom)

OBJECTIVE: Fast and non-invasive systems of the three-dimensional (3D) technology are a recent trend in orthodontics. The reproducibility of facial landmarks is important so that 3D facial measurements are accurate and may-be applied clinically. The aim of this study is to evaluate the reproducibility of facial soft tissue landmarks using a non-invasive stereo-photogrammetry 3D camera. MATERIAL AND METHODS: Twenty-four soft tissue landmarks on 3D facial images captured using a VECTRA-3D dual module camera system for full face imaging (Canfield Scientific inc, Fairfield, NJ, USA) were viewed and analysed using Mirror software on 30 adult subjects (15 males and 15 females, in the age range of 20-25 years). The landmarks were identified, recorded and measured twice on each 3D facial image by one examiner after a 2-week interval. Intra-class correlations and paired t-test or Wilcoxon Rank test were performed for each landmark to assess intra-examiner reproducibility. RESULTS: Intra-class correlation coefficients for all 24 landmarks ranged from 0.68 to 0.97, indicating moderate to high reliability and reproducibility of all facial soft tissue landmarks. Paired t-tests and Wilcoxon Rank test also revealed that there were no significant differences in all 24 facial soft tissue landmarks measurements (p = 0. 17 - 0.99). CONCLUSION: The results indicated that the reproducibility of identification of landmarks by one operator on facial images captured using a VECTRA-3D camera was acceptable. This device may be useful in treatment planning and may provide accurate information in making clinical decisions. However, it is suggested that further studies on inter-examiner reproducibility should be undertaken.

Othman SA; Ahmad R; Mericant AF; Jamaludin M

2013-05-01

 
 
 
 
301

Probabilistic anatomical labeling of brain structures using statistical probabilistic anatomical maps  

Energy Technology Data Exchange (ETDEWEB)

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

Kim, Jin Su; Lee, Dong Soo; Lee, Byung Il; Lee, Jae Sung; Shin, Hee Won; Chung, June Key; Lee, Myung Chul [Seoul National University College of Medicine, Seoul (Korea, Republic of)

2002-12-01

302

Landmark Image Super-resolution by Retrieving Web Images.  

UK PubMed Central (United Kingdom)

This paper proposes a new super-resolution (SR) scheme for landmark images by retrieving correlated web images. Using correlated web images significantly improves the exemplarbased SR. Given a low-resolution (LR) image, we extract local descriptors from its up-sampled version and bundle the descriptors according to their spatial relationship to retrieve correlated highresolution (HR) images from the web. Though similar in content, the retrieved images are usually taken with different illumination, focal lengths, and shot perspectives, resulting in uncertainty for the HR detail approximation. To solve this problem, we first propose aligning these images to the up-sampled LR image through a global registration, which identifies the corresponding regions in these images and reduces the mismatching. Second, we propose a structure-aware matching criterion and adaptive block sizes to improve the mapping accuracy between LR and HR patches. Finally, these matched HR patches are blended together by solving an energy minimization problem to recover the desired HR image. Experimental results demonstrate that our SR scheme achieves significant improvement compared with four state-of-the-art schemes in terms of both subjective and objective qualities.

Yue H; Sun X; Yang J; Wu F

2013-08-01

303

Regularized emission tomography reconstruction using adaptive filtering and anatomical prior  

International Nuclear Information System (INIS)

[en] Full text: In emission tomography, a substantial amount of smoothing is often required for suppression of noise in the reconstructed images. A technique based on minimum cross-entropy (MXE) has been developed that utilizes both functional and anatomical data for edge-preserving regularization of SPET reconstruction. MXE provides a natural scheme for using an edge-preserving smoothing filter for coding edge information obtained from CT or MR images. A limitation is that smoothing that is constrained to within anatomical boundaries may reduce edge resolution in areas where variation in functional data does not align with anatomical boundaries. To overcome this problem, we have introduced a filter that is both adaptive to the anatomical edges and the functional edges defined in previous iterations. A brain phantom with lesions has been constructed to represent emission and anatomical data. The phantom was forward-projected with Poisson noise, depth-dependent detector resolution, uniform linear attenuation coefficient and fan-beam geometry. Projections were generated for clinically realistic counts. The phantom was designed for quantifying resolution, contrast and reconstructed noise of MXE with and without corresponding anatomical prior. Our findings confirm that MXE reconstruction provides significant improvement in the signal-to-noise ratio; smaller variance for lesions; and better recovery coefficients compared to maximum likelihood reconstructions. The algorithm therefore appears to provide a regularized solution that incorporates anatomical prior information without loss of emission edge definition

1999-01-01

304

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

Directory of Open Access Journals (Sweden)

Full Text Available OBJETIVOS: Describir los resultados funcionales y anatómicos obtenidos con la facoemulsificación coaxial estándar por la técnica de multichop en la cirugía de catarata. MÉTODOS: Estudio descriptivo, longitudinal y prospectivo en el período comprendido entre septiembre de 2005 y mayo de 2007, de pacientes operados de catarata en el Instituto Cubano de Oftalmología "Ramón Pando Ferrer". RESULTADOS: El poder del ultrasonido promedio fue de 20,7 %, el tiempo de ultrasonido medio fue de 46 segundos y el tiempo efectivo de facoemulsificación promedio fue de 10,2 s; existió relación significativa entre la dureza del núcleo y el tiempo de ultrasonido empleado (p OBJECTIVES: To describe the functional and anatomical results achieved in standard coaxial phacoemulsification using multichop technique in the cataract surgery. METHODS: Prospective longitudinal and descriptive study of patients operated on from cataract at "Ramón Pando Ferrer" Cuban Institute of Ophthalmology, conducted from September 2005 to May 2007. RESULTS: The average ultrasound power was 20,7 %, the average ultrasound time was 46 seconds and the average effective phaco time was 10,3 seconds; there was significant relation between nucleus hardness and time of ultrasound (p < 0.05). Postoperative best corrected average visual acuity was 0,8 with significant relation (p = 0.00) as well as induced astigmatism of 0,37 dioptres. Significant relation was observed between loss of endothelial cells and nucleus hardness (p < 0.05). CONCLUSIONS: The used phacodynamic parameters were low, postoperative visual acuity improved and induced astigmatism was also low.

Neisy Bernal Reyes; Luis Curbelo Cunill; Alejandro Arias Díaz

2009-01-01

305

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

Scientific Electronic Library Online (English)

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

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

2009-12-01

306

Anatomical relationships and branching patterns of the dorsal cutaneous branch of the ulnar nerve.  

UK PubMed Central (United Kingdom)

PURPOSE: To describe the variable branching patterns of the dorsal cutaneous branch of the ulnar nerve (DCBUN) relative to identifiable anatomical landmarks on the ulnar side of the wrist. METHODS: We dissected the ulnar nerve in 28 unmatched fresh-frozen cadavers to identify the DCBUN and its branches from its origin to the level of the metacarpophalangeal joints. The number and location of branches of the DCBUN were recorded relative to the distal ulnar articular surface. Relationships to the subcutaneous border of the ulna, the pisotriquetral joint, and the extensor carpi ulnaris tendon were defined in the pronated wrist. RESULTS: On average, 2 branches of the DCBUN were present at the level of the distal ulnar articular surface (range, 1-4). On average, 2.2 branches were present 2 cm distal to the ulnar articular surface (range, 1-4). At least 1 longitudinal branch crossed dorsal to the extensor carpi ulnaris tendon prior to its insertion at the base of the fifth metacarpal in 23 of 28 specimens (82%). In 27 of 28 specimens (96%), all longitudinal branches of the DCBUN coursed between the dorsal-volar midpoint of the subcutaneous border of the ulna and the pisotriquetral joint. In 20 of 28 specimens (71%), a transverse branch of the DCBUN to the distal radioulnar joint was present. CONCLUSIONS: During exposure of the dorsal and ulnar areas of the wrist, identification and protection of just a single branch of the DCBUN are unlikely to ensure safe dissection because multiple branches normally are present. The 6U, 6R, and ulnar midcarpal arthroscopy portals may place these branches at risk. In the pronated forearm, the area between the DCBUN and the pisotriquetral joint contained all longitudinal branches of the DCBUN in 96% of specimens. CLINICAL RELEVANCE: During surgery involving the dorsal and ulnar areas of the wrist, multiple longitudinal branches and a transverse branch of the DCBUN are normally present and must be respected.

Root CG; London DA; Schroeder NS; Calfee RP

2013-06-01

307

77 FR 53230 - Landmarks Committee of the National Park System Advisory Board Meeting  

Science.gov (United States)

...Landmarks Committee may consider the following nominations: Alabama EDMUND PETTUS BRIDGE, Dallas County Connecticut HARRIET BEECHER STOWE HOUSE, Hartford Illinois SECOND PRESBYTERIAN CHURCH, Chicago Kentucky CAMP NELSON HISTORIC AND...

2012-08-31

308

Accuracy and landmark error calculation using cone-beam computed tomography-generated cephalograms.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To evaluate systematic differences in landmark position between cone-beam computed tomography (CBCT)-generated cephalograms and conventional digital cephalograms and to estimate how much variability should be taken into account when both modalities are used within the same longitudinal study. MATERIALS AND METHODS: Landmarks on homologous cone-beam computed tomographic-generated cephalograms and conventional digital cephalograms of 46 patients were digitized, registered, and compared via the Hotelling T(2) test. RESULTS: There were no systematic differences between modalities in the position of most landmarks. Three landmarks showed statistically significant differences but did not reach clinical significance. A method for error calculation while combining both modalities in the same individual is presented. CONCLUSION: In a longitudinal follow-up for assessment of treatment outcomes and growth of one individual, the error due to the combination of the two modalities might be larger than previously estimated.

Grauer D; Cevidanes LS; Styner MA; Heulfe I; Harmon ET; Zhu H; Proffit WR

2010-03-01

309

Milestones in movement disorders clinical trials: advances and landmark studies.  

UK PubMed Central (United Kingdom)

Over the past 25 years clinical trials testing in movement disorders has evolved in order to more effectively and efficiently analyze the safety and efficacy of new interventions. Studies today regularly incorporate methods to decrease placebo and bias effects and to ensure more rigorous statistical analyses. Newer, standardized, and validated rating scales such as the Unified Parkinson's Disease Rating Scale and the Unified Huntington's Disease Rating Scale are routinely employed in an effort to produce results that are comparable across different sites and studies. Several landmark studies in movement disorder research highlight these and other prominent procedural advances. The Deprenyl and Tocopherol Antioxidative Therapy of Parkinsonism trial pioneered the use of functional clinical end points, utilized a 2 × 2 factorial design to more efficiently analyze multiple interventions, and employed a washout design to assist in sorting putative neuroprotective from symptomatic effects. PRECEPT included neuroimaging as an outcome measure and highlighted the importance of futility studies in more efficiently directing resources. TEMPO and ADAGIO introduced the use of delayed-start (or 2-period) trials to try to identify disease-modifying interventions. NET-PD used futility studies to streamline the evaluation of potentially valuable treatments, followed by a large, long-term simple study design to assess the clinical significance of a new intervention. There have also been advances in clinical trials testing new surgical interventions, with the introduction of blinded outcome assessments and sham-surgery control groups. Collectively, methodological advances in clinical trials have permitted the safety and efficacy of new interventions to be tested more efficiently and economically and with a higher level of certainty that the potential benefits and adverse effects of interventions recommended for general use are well understood.

Olanow CW; Wunderle KB; Kieburtz K

2011-05-01

310

Restriction landmark genome scanning for the detection of mutations.  

UK PubMed Central (United Kingdom)

There is a continuing need for more efficient methods to examine mutations in humans and other species resulting from exposures to environmental toxins and radiation. Environmental genomic studies, which often utilize nonmodel system species and as a result, there is a particular need for a method that does not rely on the availability of genome sequence information. Restriction landmark genome scanning (RLGS) is a two-dimensional electrophoresis (2-DE) of end-labeled DNA fragments. A vertical giant gel 2-DE system has been developed and applied to the RLGS. On a single RLGS pattern of mouse or human DNA, approx 2000 DNA fragments (spots) varying in size from 1.0 to 5.0 kb in the first dimension and 0.2 to 3.0 kb in the second dimension are visualized. In principle, this system will detect genomic alterations of two types: (1) that due to gain or loss of a cut site for the three restriction fragment enzymes employed in the study and (2) that due to insertion/deletion/rearrangement (I/D/R) events. After optimization of the sample preparation and electrophoresis conditions, the gel quality reached a level such that the electrophoresis patterns derived from a single DNA sample gave distribution patterns of spots able to be superimposed. This technology can visualize up to 3000 DNA fragments per gel without using any probes, and thus should be highly efficient in monitoring for mutations resulting in I/D/R events in DNA fragments distributed throughout the genome. This method relies on direct labeling of DNA fragments rather than hybridization and therefore precise information on genome sequences is not required. As a result this method is applicable to any species.

Asakawa J

2008-01-01

311

Evaluation of Some Anatomical and Anthropometric Characteristics of the Chest Based on the Analysis of Digital Images of the Anterior Aspect of Trunk in Top Athletes  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of this research was to assess the size and shape of the chest in students and top athletes. The research involved 23 first-year students of the Faculty of Sport and Physical Education, and 23 top athletes of the Athletic Federation of Serbia. The digital images of the frontal trunk aspect were made and further analyzed in ImageJ program. The vertical and horizontal distances and as well as the angles were determined: the infrasternal angle and the angle of umbilicus (sides of the angle connect the points on the left and right). Both students and athletes were divided into three height groups (I – 165-174 cm; II – 175-184 cm; III – 185-194 cm). BMI and BI were determined (shoulder width. No statistical differences in height, weight and BMI among the groups of students and top athletes were found, which pointed to the homogeneity of the groups. All the parameters determined, the vertical and horizontal ones, except AAD, were significantly higher in top athletes (p?0.05) compared to the same parameters obtained in students of all three height groups. Acromial distance increases with height, but not statistically significantly. The above mentioned indicates a significantly better development of the bone-joint-muscle system of the chest in top athletes. The infrasternalni angle correlates with the angle of the umbilicus and it can be used to assess the shape of the chest. In our researches, analysing the individual cases, the presence of normasthenic, asthenic (elongated) and barrel-shaped chest was determined. The program ImageJ is very precise, objective and easily applicable for determining the lenghtwise parameters and angles in anatomic and anthropometric measurements. The method does not require anthropometric equipment, digital images can be made quickly and efficiently. Therefore, we consider it particularly suitable for measurements in childhood and athletes.

Natalija Stefanovi?; Ivana Mladenovi? ?iri?; Snežana Pavlovi?; Braca Kundali?; Saša Bubanj; Emilija Petkovi?; Miloš Puleti?; Vlada Anti?

2012-01-01

312

Compensation for fluctuations in crosswind drift without stationary landmarks in butterflies migrating over seas.  

UK PubMed Central (United Kingdom)

Migrating insects may fly over large bodies of water that lack landmarks, but little is known about their ability to navigate in such a fluid environment. Using boat navigation instruments to measure compensation for fluctuations in crosswind drift, I investigated the ability of butterflies (Lepidoptera: Hesperiidae, Nymphalidae and Pieridae) to orient with and without landmarks as they migrated naturally over the Caribbean Sea. I used the presence or absence of landmarks or clouds to evaluate their use by the butterflies as guides for compensation. Forty-one per cent of the butterflies compensated for crosswind drift, whereas only 16% did not compensate. No conclusion could be drawn for the remainder. Without landmarks or clouds, butterflies were significantly less likely to compensate for drift than when these local cues were present. Butterflies were more likely to compensate fully in the presence of a landmark than when only clouds were present. Phoebis sennae butterflies drifted in the morning and overcompensated for drift in the afternoon, a pattern found both within and between individuals independent of landmarks. Although I cannot exclude the use of clouds, this would probably result in undercompensation. Hence, a ground reference in conjunction with a sun or magnetic compass is the most likely orientation cue. In the absence of clouds, one butterfly compensated, at least in part, indicating that it was using ripples on the sea surface as a ground reference in conjunction with a sun or magnetic compass. Copyright 2001 The Association for the Study of Animal Behaviour.

Srygley RB

2001-01-01

313

Clinical study of quantitative analysis of the anatomical structure after canalicular laceration  

Directory of Open Access Journals (Sweden)

Full Text Available AIM: To quantitatively analyse the anatomical structure after canalicular laceration, to provide a basis for finding nasal ends of the canalicular and to evaluate the feasibility of taking the lacrimal caruncle as anatomic landmarks for finding the nasal ends of the inferior canalicular. METHODS: In this prospective case-control study, 100 cases(72 males and 28 females)of traumatic inferior canalicular laceration were chosen. They were completely random divided into the experimental group(n=50), finding the nasal ends of the inferior canalicular by applying the method of lacrimal caruncle anatomic landmarks; the control group(n=50), finding the nasal ends of the inferior canalicular by applying the direct vision method. The distance of the lacrimal punctum and the temporal side of the stump, the vertical distance and quadrant between nasal ends of the canalicular and lacrimal caruncle were measured. The success rate of the two groups to find the nasa lends of the canalicular were recorded. The data were compared using ?2 test. RESULTS: The nasal ends of the inferior canalicular in the semi-quadrant of the lacrimal caruncle was 94%. The canalicular nasal ends from the lacrimal caruncle of the vertical distance was 2.34±0.68 mm,in which lacrimal punctums pitch temporal side of the stump7mm was 3.05±0.97mm. The success rate of surgery looking the inferior lacrimal duct nasal stump: experimental group: 49/50(98%), control group: 40/50(80%), the difference was statistically significant(PCONCLUSION: Nasal ends of the inferior canalicular locates below the parallel lines of the lacrimal caruncle. The canalicular nasal ends locates in the deep side of the lacrimal caruncle within 2-3mm. The lacrimal punctum and the length of the temporal side can be used to clear the radius around the lacrimal caruncle. The success rate of finding the nasal ends of the experimental group is faster than the control group. The lacrimal caruncle as anatomic landmarks to find the nasal ends of the inferior canalicular is feasible, especially for patients whose inferior canalicular bitamporal side of the stump from inferior lacrimal punctum was 4-7mm.

Min Wei; Shu-Sen Jiang; Hong-Qi Wu; Qiu-Feng Zong

2013-01-01

314

Obturator neuropathy. An anatomic perspective.  

Science.gov (United States)

Entrapment of the anterior division of the obturator nerve is a recently described cause of medial groin pain. This anatomic study examines the extrapelvic course of the nerve and related fascia in the adductor region to provide an anatomic basis for the syndrome and to aid in surgical treatment. Twelve anatomic specimen limbs were dissected to document the extrapelvic course of the obturator nerve, the myofascial arrangement, and the vasculature. A thirteenth limb was prepared with intraarterial glycerin to examine the vessels in more detail. A distinct fascial plane was found deep to the adductor longus and pectineus overlying the anterior division of the obturator nerve. The arterial supply to the adductor muscles is related intimately to the nerve and its branches, with associated local thickening of the fascial connective tissue. The relationship between the nerve, vessels, and fascia appears sufficient to result in an entrapment syndrome. The anatomic findings from this series will help plan the surgical treatment of this condition. PMID:10379324

Harvey, G; Bell, S

1999-06-01

315

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

UK PubMed Central (United Kingdom)

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.

Lopez-Serna R; Gomez-Amador JL; Barges-Coll J; Arriada-Mendicoa N; Romero-Vargas S; Ramos-Peek M; Celis-Lopez MA; Revuelta-Gutierrez R; Portocarrero-Ortiz L

2012-08-01

316

Anatomical correlates of blepharospasm  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Focal dystonia is a neurological disorder characterized by unwanted muscle spasms. Blepharospasm is a focal dystonia producing an involuntary closure of the eyelid. Its etiology is unknown. Objective To investigate if there are structural changes in the white and grey matter of blepharospasm patients, and if the changes are related to disease features. Methods T1 and diffusion-weighted magnetic resonance imaging scans were collected from 14 female blepharospasm patients and 14 healthy matched controls. Grey matter volumes, fractional anisotropy (FA), and mean diffusivity maps were compared between the groups. Based on grey matter differences within the facial portion of the primary motor cortex, the corticobulbar tract was traced and compared between groups. Results Changes in grey matter in patients included the facial portion of the sensorimotor area and anterior cingulate gyrus. These changes did not correlate with disease duration. Corticobulbar tract volume and peak tract connectivity were decreased in patients compared with controls. There were no significant differences in FA or mean diffusivity between groups. Conclusions Grey matter changes within the primary sensorimotor and the anterior cingulate cortices in blepharospasm patients may help explain involuntary eyelid closure and the abnormal sensations often reported in this condition.

Horovitz Silvina G; Ford Anastasia; Najee-ullah Muslimah; Ostuni John L; Hallett Mark

2012-01-01

317

Piriformis syndrome resulting from a rare anatomic variation.  

UK PubMed Central (United Kingdom)

STUDY DESIGN: Case report. OBJECTIVES: We report a rare case of piriformis syndrome accompanying anatomic variation in the piriformis muscle and sciatic nerve. SUMMARY OF BACKGROUND DATA: Beaton classified anatomic variation in the piriformis muscle and sciatic nerve into 6 types based on cadaver studies. There has been no report in the English literature of surgical treatment for a case of piriformis syndrome accompanying Beaton type d anatomic variation. METHODS: A patient with sciatica showing no nerve root compression in lumbar MRI underwent pelvic MRI and perineurography of the sciatic nerve followed by CT. The findings in these images suggested piriformis syndrome accompanying anatomic variation of the piriformis muscle and sciatic nerve. Surgical treatment was performed. RESULTS: Surgical exploration of the piriformis muscle revealed Beaton type d anatomic variation. Both anterior and posterior lobes of the piriformis muscle were resected. The pain in the leg had completely disappeared after surgery. CONCLUSIONS: This is a very rare case of surgically treated piriformis syndrome resulting from type d anatomic variation in Beaton's classification. Pelvic MRI and perineurography of the sciatic nerve were useful for diagnosis in this case.

Kosukegawa I; Yoshimoto M; Isogai S; Nonaka S; Yamashita T

2006-08-01

318

An anatomic study of the distal femoral epiphysis.  

UK PubMed Central (United Kingdom)

BACKGROUND: The anatomy of the undulating distal femoral physis may be relevant to growth disturbance after physeal fractures and screw fixation about the physis. The surface anatomy of this physis has not been well described. METHODS: We performed an anatomic study on 26 cadaveric distal femoral epiphyses in specimens 3 to 18 years of age. High-resolution 3-dimensional surface scans were obtained and analyzed to determine the heights, approximate surface areas, and locations of the major undulations. RESULTS: Gross examination revealed lateral and anteromedial peripheral notches at the metaphyseal-epiphyseal junction, which deepen with advancing skeletal maturity. Within the epiphysis, there are 3 major undulations: a central ridge, lateral ridge, and medial peak, with mean heights of 5.5 mm (range, 2.9 to 9.8 mm), 2.5 mm (1.0 to 5.7 mm), and 2.9 mm (0.9 to 4.7 mm), respectively. The normalized height and surface area of each undulation decreased with increasing age, most dramatically in the central ridge. With respect to a line connecting the medial and lateral aspects of the physis, we found that the central peak passes more superior with younger age, and tends to be more posteriorly located. The lowest point of the physis is located either anteromedial or posterolateral. CONCLUSIONS: The central ridge, lateral ridge, and medial peak are the 3 major undulations in the distal femoral physis. The central ridge has the greatest height and most dramatic decrease in relative size with increasing age, suggesting structural importance. This anatomic data can guide metaphyseal and epiphyseal screw fixation. CLINICAL RELEVANCE: This study provides quantitative data on the topographic anatomy of the distal femoral physis, which can guide screw placement about the physis. These data may help identify fractures patterns with a greater risk of growth disturbance and key radiographic landmarks for guiding fracture reduction.

Liu RW; Armstrong DG; Levine AD; Gilmore A; Thompson GH; Cooperman DR

2013-10-01

319

Anatomical structure of Polystichum Roth ferns rachises  

Directory of Open Access Journals (Sweden)

Full Text Available The morpho-anatomical characteristics of rachis cross sections of five Polystichum species is presented. The main and auxiliary anatomical features which help to distinguish investigated species are revealed.

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

2012-01-01

320

Cranial and cerebral-ventricular landmarks for accurate stereotaxic approach to hypothalamic nuclei in the goat brain.  

UK PubMed Central (United Kingdom)

This paper describes a new stereotaxic coordinate system for the goat brain based on cranial landmarks. An osseous triangle (a-b-c) formed by the point of junction of the crista galli with the caudal ventral part of the frontal sinus septum (a), the external occipital protuberance (b), and the midsagittal projection of the external acoustic meatus (c), was measured using lateral radiographs and ventriculographs and showed a constant mathematical relation. The rostral angle was 20.3 +/- 1.0 (mean +/- SD) degree in 23 goats studied regardless of their cranial size which varied considerably from one animal to another. The hypotenuse length (a-b distance) was found to be a good predictor of the rostral nuchal position of the anterior commissure (AC) and the infundibular recess of the third ventricle (INF), by which the individual variance of the stereotaxic coordinates for a given hypothalamic structure could be compensated. The anterior-posterior distances from the external acoustic meatus was highly correlated with the a-b distance for AC (r = 0.88) and INF (r = 0.90). Using these cranial landmarks and the method outlined in this paper, uncertainty in coordinate values for AC and INF in the goat brain was reduced considerably in comparison to deviation observed when the ordinary Horsley-Clarke axis (Reid's plane) was employed.

Zuccolilli GO; Mori Y

1995-06-01

 
 
 
 
321

[Anatomic study of parapharyneal space].  

Science.gov (United States)

The parapharyngeal space is considered the key space of the suprahioid neck, being essential to establish the origin and anatomic relations of the lesions of the profound neck. The descriptions of the fascial limits of the parapharyngeal space are variable in the litterature, reflecting some ambiguity in the manuals of anatomy and surgery. We have done a detailed study of this region, working on 5 cadavers, fixed in a solution of phenol and alcohol, and correlating the disection pieces with a radiologic study. The goal has been to improve our anatomic knowledge of the suprahioid neck, to be able to establish an anatomo-clinic-radiologic correlation of the lesions of this region, to be able to establish an differential diagnosis, predict possible ways of dissemination and facilitate the most proper surgical approach. PMID:15566269

Tornero Saltó, J; Rodríguez Baeza, A; Rovira Cañellas, A; Juan Prada, A; Maños Pujol, M; Palau Viarnés, M; Dicenta Sousa, M

2004-01-01

322

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

Science.gov (United States)

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

Grzybowski, Andrzej; McGhee, Charles N J

2013-02-18

323

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

UK PubMed Central (United Kingdom)

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

Grzybowski A; McGhee CN

2013-03-01

324

Anatomic variations on PNS CT  

Energy Technology Data Exchange (ETDEWEB)

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

325

Anatomic variations on PNS CT  

International Nuclear Information System (INIS)

[en] 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

1994-01-01

326

Gaze-centered spatial updating in delayed reaching even in the presence of landmarks.  

Science.gov (United States)

Previous results suggest that the brain predominantly relies on a constantly updated gaze-centered target representation to guide reach movements when no other visual information is available. In the present study, we investigated whether the addition of reliable visual landmarks influences the use of spatial reference frames for immediate and delayed reaching. Subjects reached immediately or after a delay of 8 or 12s to remembered target locations, either with or without landmarks. After target presentation and before reaching they shifted gaze to one of five different fixation points and held their gaze at this location until the end of the reach. With landmarks present, gaze-dependent reaching errors were smaller and more precise than when reaching without landmarks. Delay influenced neither reaching errors nor variability. These findings suggest that when landmarks are available, the brain seems to still use gaze-dependent representations but combine them with gaze-independent allocentric information to guide immediate or delayed reach movements to visual targets. PMID:23770521

Schütz, I; Henriques, D Y P; Fiehler, K

2013-06-12

327

Gaze-centered spatial updating in delayed reaching even in the presence of landmarks.  

UK PubMed Central (United Kingdom)

Previous results suggest that the brain predominantly relies on a constantly updated gaze-centered target representation to guide reach movements when no other visual information is available. In the present study, we investigated whether the addition of reliable visual landmarks influences the use of spatial reference frames for immediate and delayed reaching. Subjects reached immediately or after a delay of 8 or 12s to remembered target locations, either with or without landmarks. After target presentation and before reaching they shifted gaze to one of five different fixation points and held their gaze at this location until the end of the reach. With landmarks present, gaze-dependent reaching errors were smaller and more precise than when reaching without landmarks. Delay influenced neither reaching errors nor variability. These findings suggest that when landmarks are available, the brain seems to still use gaze-dependent representations but combine them with gaze-independent allocentric information to guide immediate or delayed reach movements to visual targets.

Schütz I; Henriques DY; Fiehler K

2013-07-01

328

Automated landmark extraction for orthodontic measurement of faces using the 3-camera photogrammetry methodology.  

UK PubMed Central (United Kingdom)

OBJECTIVES: To set up a three-dimensional photogrammetric scanning system for precise landmark measurements, without any physical contact, using a low-cost and noninvasive digital photogrammetric solution, for supporting several necessity in clinical orthodontics and/or surgery diagnosis. MATERIALS AND METHODS: Thirty coded targets were directly applied onto the subject's face on the soft tissue landmarks, and then, 3 simultaneous photos were acquired using photogrammetry, at room light conditions. For comparison, a dummy head was digitized both with a photogrammetric technique and with the laser scanner Minolta Vivid 910i (Konica Minolta, Tokyo, Japan). RESULTS: The precise measurement of the landmarks is ranged between 0.017 and 0.029 mm. The system automatically measures spatial position of face landmarks, from which distances and angles can be obtained. The facial measurements were compared with those done using laser scanning and manual caliper. The adopted method gives higher precision than the others (0.022-mm mean value on points and 0.038-mm mean value on linear distances on a dummy head), is simple, and can be used easily as a standard routine. CONCLUSIONS: The study demonstrated the validity of photogrammetry for accurate digitization of human face landmarks. This research points out the potential of this low-cost photogrammetry approach for medical digitization.

Deli R; Di Gioia E; Galantucci LM; Percoco G

2010-01-01

329

ANTHEM: anatomically tailored hexagonal MRI.  

UK PubMed Central (United Kingdom)

PURPOSE: This study aimed to investigate the use of anatomically tailored hexagonal sampling for scan-time and error reduction in MRI. MATERIALS AND METHODS: Anatomically tailored hexagonal MRI (ANTHEM), a method that combines hexagonal sampling with specific symmetry in anatomical geometry, is proposed. By using hexagonal sampling, aliasing artifacts are moved to regions where, due to the nature of the anatomy, aliasing is inconsequential. This can be used to either reduce scan time while maintaining spatial resolution or reduce residual errors in speedup techniques like UNFOLD and k-t BLAST/SENSE, which undersample k-space and unwrap fold-over artifacts during reconstruction. Computer simulations as well as phantom and volunteer studies were used to validate the theory. A simplified reconstruction algorithm for hexagonally sampled and subsampled k-space data was also used. RESULTS: A reduction in sampling density of 13.4% and 25% in each hexagonally sampled dimension was achieved for spherical and conical geometries without aliasing or reduction in spatial resolution. Optimal subsampling schemes that can be utilized by UNFOLD and k-t BLAST/SENSE were derived using hexagonal subsampling, which resulted in maximal, isotropic dispersal of the aliases. In combination with UNFOLD, ANTHEM was shown to move residual aliasing artifacts to the corners of the field of view, yielding reduced artifacts in CINE reconstructions. CONCLUSIONS: ANTHEM was successful in reducing acquisition time in conventional MRI and in reducing errors in UNFOLD imaging.

Saranathan M; Ramanan V; Gulati R; Venkatesan R

2007-09-01

330

Minimizing femoral access complications in patients undergoing percutaneous coronary interventions: a proposed strategy of bony landmark guided femoral access, routine access site angiography and appropriate use of closure devices.  

UK PubMed Central (United Kingdom)

INTRODUCTION: In this study we report local complication rates in patients undergoing percutaneous coronary intervention (PCI) utilizing a strategy of fluoroscopically guided puncture and preferential use of a closure device based on access site angiography. METHODS: We included 201 consecutive PCIs where the initial puncture was fluoroscopically guided using the inferior border of the femoral head as the guiding bony landmark. At the end of each PCI, access site angiography determined whether the deployment of a closure device, specifically the Angioseal device, was anatomically feasible. The access site was evaluated 3 and 24 hours post PCI. All patients were contacted by phone 30 days following the index procedure and questioned about any further incidents following hospital discharge. RESULTS: Deployment of the Angioseal device was feasible in 76% (153/201) of cases with a success rate over 99% (152/153). In the remaining 48 patients the access site was managed with manual compression, elastic bandage placement and prolonged bed rest. Patients who received the Angioseal device could be mobilized after 6 hours, while the group that was managed with manual compression required overnight bed rest. Local complication rates where very low for the study group as a whole (1.5%) without significant differences associated with the use of the Angioseal device. We did not observe any significant influence of the established risk factors for local complications, such as age, female sex, sheath size, elevated systolic blood pressure or use of glycoprotein IIb/IIIa platelet inhibitors, within our study population. CONCLUSION: The appropriate use of the Angioseal is feasible in three quarters of patients undergoing PCI and allows for more rapid mobilization while ensuring very low local complication rates.

Tzinieris IN; Papaioannou GI; Dragomanovits SI; Deliargyris EN

2007-05-01

331

Wayfinding behavior and spatial knowledge of adults and children in a virtual environment: The role of landmarks.  

UK PubMed Central (United Kingdom)

This study investigated the effect of different organizations of landmark-location pairings as fine-space information on wayfinding behavior and spatial knowledge on a total of 90 participants: 30 second graders, 30 sixth graders, and 30 adults. All participants had to find their way to a goal in a virtual environment with either randomized or categorical landmarks, or without any landmarks. Thereafter, they had to find the shortest way from the start position to the goal in two consecutive trials (wayfinding performance), and they had to solve a number of spatial knowledge tasks. The results showed that independent of their categorical function, the existence of landmarks influenced the way-finding performance of adults and children in the same way. Whereas the presence of landmarks had no effect on spatial survey knowledge, landmark knowledge itself was influenced by the categorical function of the landmarks presented. Moreover, second graders showed limited achievement compared to adults independent of the existence of landmarks. The main results implicate firstly that children at school age indeed are able to use landmark-location pairings as fine-space information like adults during learning an unknown environmental space, and secondly that a dissociation between wayfinding behavior and spatial knowledge might exist.

Jansen-Osmann P; Fuchs P

2006-01-01

332

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

Scientific Electronic Library Online (English)

Full Text Available Abstract in english 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 plac (more) ement, 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

Turker, Gurkan; Kaya, Fatma Nur; Gurbet, Alp; Aksu, Hale; Erdogan, Cuneyt; Atlas, Ahmet

2009-01-01

333

The influence of excitatory and inhibitory landmarks on choice in environments with a distinctive shape.  

UK PubMed Central (United Kingdom)

In two experiments rats were trained to find one of two submerged platforms that were located in diagonally opposite corners-the correct corners-of a rectangular pool. Additional training was given to endow two different landmarks with excitatory and inhibitory properties, by using them to indicate where a platform was or was not located in either a rectangular (Experiment 1) or a square pool (Experiment 2). Subsequent test trials, with the platforms removed from the pool, revealed that placing the excitatory landmark in each of the four corners of the rectangle resulted in more time being spent in the correct corners than when the four corners contained inhibitory landmarks. This result is contrary to predictions derived from a choice rule for spatial behavior proposed by Miller and Shettleworth (2007).

Horne MR; León SP; Pearce JM

2013-01-01

334

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

UK PubMed Central (United Kingdom)

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

Frankenstein J; Brüssow S; Ruzzoli F; Hölscher C

2012-08-01

335

Influence of local objects on hippocampal representations: Landmark vectors and memory.  

Science.gov (United States)

The hippocampus is thought to represent nonspatial information in the context of spatial information. An animal can derive both spatial information as well as nonspatial information from the objects (landmarks) it encounters as it moves around in an environment. In this article, correlates of both object-derived spatial as well as nonspatial information in the hippocampus of rats foraging in the presence of objects are demonstrated. A new form of CA1 place cells, called landmark-vector cells, that encode spatial locations as a vector relationship to local landmarks is described. Such landmark vector relationships can be dynamically encoded. Of the 26 CA1 neurons that developed new fields in the course of a day's recording sessions, in eight cases, the new fields were located at a similar distance and direction from a landmark as the initial field was located relative to a different landmark. In addition, object-location memory in the hippocampus is also described. When objects were removed from an environment or moved to new locations, a small number of neurons in CA1 and CA3 increased firing at the locations where the objects used to be. In some neurons, this increase occurred only in one location, indicating object + place conjunctive memory; in other neurons, the increase in firing was seen at multiple locations where an object used to be. Taken together, these results demonstrate that the spatially restricted firing of hippocampal neurons encode multiple types of information regarding the relationship between an animal's location and the location of objects in its environment. PMID:23447419

Deshmukh, Sachin S; Knierim, James J

2013-02-27

336

Influence of local objects on hippocampal representations: Landmark vectors and memory.  

UK PubMed Central (United Kingdom)

The hippocampus is thought to represent nonspatial information in the context of spatial information. An animal can derive both spatial information as well as nonspatial information from the objects (landmarks) it encounters as it moves around in an environment. In this article, correlates of both object-derived spatial as well as nonspatial information in the hippocampus of rats foraging in the presence of objects are demonstrated. A new form of CA1 place cells, called landmark-vector cells, that encode spatial locations as a vector relationship to local landmarks is described. Such landmark vector relationships can be dynamically encoded. Of the 26 CA1 neurons that developed new fields in the course of a day's recording sessions, in eight cases, the new fields were located at a similar distance and direction from a landmark as the initial field was located relative to a different landmark. In addition, object-location memory in the hippocampus is also described. When objects were removed from an environment or moved to new locations, a small number of neurons in CA1 and CA3 increased firing at the locations where the objects used to be. In some neurons, this increase occurred only in one location, indicating object + place conjunctive memory; in other neurons, the increase in firing was seen at multiple locations where an object used to be. Taken together, these results demonstrate that the spatially restricted firing of hippocampal neurons encode multiple types of information regarding the relationship between an animal's location and the location of objects in its environment.

Deshmukh SS; Knierim JJ

2013-04-01

337

Surface-based prostate registration with biomechanical regularization  

Science.gov (United States)

Adding MR-derived information to standard transrectal ultrasound (TRUS) images for guiding prostate biopsy is of substantial clinical interest. A tumor visible on MR images can be projected on ultrasound by using MRUS registration. A common approach is to use surface-based registration. We hypothesize that biomechanical modeling will better control deformation inside the prostate than a regular surface-based registration method. We developed a novel method by extending a surface-based registration with finite element (FE) simulation to better predict internal deformation of the prostate. For each of six patients, a tetrahedral mesh was constructed from the manual prostate segmentation. Next, the internal prostate deformation was simulated using the derived radial surface displacement as boundary condition. The deformation field within the gland was calculated using the predicted FE node displacements and thin-plate spline interpolation. We tested our method on MR guided MR biopsy imaging data, as landmarks can easily be identified on MR images. For evaluation of the registration accuracy we used 45 anatomical landmarks located in all regions of the prostate. Our results show that the median target registration error of a surface-based registration with biomechanical regularization is 1.88 mm, which is significantly different from 2.61 mm without biomechanical regularization. We can conclude that biomechanical FE modeling has the potential to improve the accuracy of multimodal prostate registration when comparing it to regular surface-based registration.

van de Ven, Wendy J. M.; Hu, Yipeng; Barentsz, Jelle O.; Karssemeijer, Nico; Barratt, Dean; Huisman, Henkjan J.

2013-03-01

338

Anatomic reference for computed tomography of paranasal sinuses and their communication in the Egyptian buffalo (Bubalus bubalis).  

UK PubMed Central (United Kingdom)

The purpose of this work was to present an anatomic reference for computed tomography (CT) for the paranasal sinuses of adult buffalo fit the use of anatomists, radiologists, clinicians and veterinary students. CT images with the most closely corresponding cross sections of the head were selected and studied serially in a rostral to caudal progression from the level of the interdental space to the level of the nuchal line. The anatomical features were compared with the dissected heads and skulls. The paranasal sinuses of buffalo comprise dorsal conchal, middle conchal, maxillary, frontal, palatine, sphenoidal (inconstant, small and shallow when present), lacrimal and ethmoidal that were identified and labelled according to the premolar and molar teeth as landmarks. The topographic description of all the compartments, diverticula, septa and communication of the paranasal sinuses in buffalo has been presented. The relationship between the various air cavities and paranasal sinuses was easily visualized.

Alsafy MA; El-Gendy SA; El Sharaby AA

2013-06-01

339

Dosimetric accuracy of a deterministic radiation transport based (192)Ir brachytherapy treatment planning system. Part III. Comparison to Monte Carlo simulation in voxelized anatomical computational models.  

UK PubMed Central (United Kingdom)

PURPOSE: To compare TG43-based and Acuros deterministic radiation transport-based calculations of the BrachyVision treatment planning system (TPS) with corresponding Monte Carlo (MC) simulation results in heterogeneous patient geometries, in order to validate Acuros and quantify the accuracy improvement it marks relative to TG43. METHODS: Dosimetric comparisons in the form of isodose lines, percentage dose difference maps, and dose volume histogram results were performed for two voxelized mathematical models resembling an esophageal and a breast brachytherapy patient, as well as an actual breast brachytherapy patient model. The mathematical models were converted to digital imaging and communications in medicine (DICOM) image series for input to the TPS. The MCNP5 v.1.40 general-purpose simulation code input files for each model were prepared using information derived from the corresponding DICOM RT exports from the TPS. RESULTS: Comparisons of MC and TG43 results in all models showed significant differences, as reported previously in the literature and expected from the inability of the TG43 based algorithm to account for heterogeneities and model specific scatter conditions. A close agreement was observed between MC and Acuros results in all models except for a limited number of points that lay in the penumbra of perfectly shaped structures in the esophageal model, or at distances very close to the catheters in all models. CONCLUSIONS: Acuros marks a significant dosimetry improvement relative to TG43. The assessment of the clinical significance of this accuracy improvement requires further work. Mathematical patient equivalent models and models prepared from actual patient CT series are useful complementary tools in the methodology outlined in this series of works for the benchmarking of any advanced dose calculation algorithm beyond TG43.

Zourari K; Pantelis E; Moutsatsos A; Sakelliou L; Georgiou E; Karaiskos P; Papagiannis P

2013-01-01

340

Dosimetric accuracy of a deterministic radiation transport based {sup 192}Ir brachytherapy treatment planning system. Part III. Comparison to Monte Carlo simulation in voxelized anatomical computational models  

Energy Technology Data Exchange (ETDEWEB)

Purpose: To compare TG43-based and Acuros deterministic radiation transport-based calculations of the BrachyVision treatment planning system (TPS) with corresponding Monte Carlo (MC) simulation results in heterogeneous patient geometries, in order to validate Acuros and quantify the accuracy improvement it marks relative to TG43. Methods: Dosimetric comparisons in the form of isodose lines, percentage dose difference maps, and dose volume histogram results were performed for two voxelized mathematical models resembling an esophageal and a breast brachytherapy patient, as well as an actual breast brachytherapy patient model. The mathematical models were converted to digital imaging and communications in medicine (DICOM) image series for input to the TPS. The MCNP5 v.1.40 general-purpose simulation code input files for each model were prepared using information derived from the corresponding DICOM RT exports from the TPS. Results: Comparisons of MC and TG43 results in all models showed significant differences, as reported previously in the literature and expected from the inability of the TG43 based algorithm to account for heterogeneities and model specific scatter conditions. A close agreement was observed between MC and Acuros results in all models except for a limited number of points that lay in the penumbra of perfectly shaped structures in the esophageal model, or at distances very close to the catheters in all models. Conclusions: Acuros marks a significant dosimetry improvement relative to TG43. The assessment of the clinical significance of this accuracy improvement requires further work. Mathematical patient equivalent models and models prepared from actual patient CT series are useful complementary tools in the methodology outlined in this series of works for the benchmarking of any advanced dose calculation algorithm beyond TG43.

Zourari, K.; Pantelis, E.; Moutsatsos, A.; Sakelliou, L.; Georgiou, E.; Karaiskos, P.; Papagiannis, P. [Medical Physics Laboratory, Medical School, University of Athens, 75 Mikras Asias, 115 27 Athens (Greece); Department of Physics, Nuclear and Particle Physics Section, University of Athens, Ilisia, 157 71 Athens (Greece); Medical Physics Laboratory, Medical School, University of Athens, 75 Mikras Asias, 115 27 Athens (Greece)

2013-01-15

 
 
 
 
341

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

UK PubMed Central (United Kingdom)

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

Matsumoto H; Sakai T

2009-12-01

342

Evaluation of contrast reproduction method based on the anatomical guidance of the cerebral images reconstruction in positron emission tomography; Evaluation d'une methode de restitution de contraste basee sur le guidage anatomique de la reconstruction des images cerebrales en tomographie par emission de positons  

Energy Technology Data Exchange (ETDEWEB)

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

Bataille, F

2007-04-15

343

Utilization Management in Anatomic Pathology.  

UK PubMed Central (United Kingdom)

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

Lewandrowski K; Black-Schaffer S

2013-10-01

344

Three-dimensional musculoskeletal kinematics during bipedal locomotion in the Japanese macaque, reconstructed based on an anatomical model-matching method.  

UK PubMed Central (United Kingdom)

Studying the bipedal locomotion of non-human primates is important for clarifying the evolution of habitual bipedalism in the human lineage. However, quantitative descriptions of three-dimensional kinematics of bipedal locomotion in non-human primates are very scarce, due to difficulties associated with measurements. In this study, we performed a kinematic analysis of bipedal locomotion on two highly trained (performing) Japanese macaques walking on a treadmill at different speeds and estimated three-dimensional angular motions of hindlimb and trunk segments, based on a model-based registration method. Our results demonstrated a considerable degree of axial rotation occurring at the trunk and hip joints during bipedal locomotion, suggesting that bipedal locomotion in Japanese macaques is essentially three-dimensional. In addition, ranges of angular motions at the hip and ankle joints were larger and the knee joint was more flexed in the mid-stance phase with increasing speed, indicating that gait kinematics are modulated depending on speed. Furthermore, macaques were confirmed to have actually acquired, at least to some extent, the energy conservation mechanism of walking due to pendular exchange of potential and kinetic energy, but effective utilization of this mutual exchange of energy was found to occur only at comparatively low velocity. Spring-like running mechanics were probably more exploited at higher speed because the duty factor was above 0.5. Fundamental differences in bipedal strategy seem to exist between human and non-human primate bipedal locomotion.

Ogihara N; Makishima H; Nakatsukasa M

2010-03-01

345

Three-dimensional musculoskeletal kinematics during bipedal locomotion in the Japanese macaque, reconstructed based on an anatomical model-matching method.  

Science.gov (United States)

Studying the bipedal locomotion of non-human primates is important for clarifying the evolution of habitual bipedalism in the human lineage. However, quantitative descriptions of three-dimensional kinematics of bipedal locomotion in non-human primates are very scarce, due to difficulties associated with measurements. In this study, we performed a kinematic analysis of bipedal locomotion on two highly trained (performing) Japanese macaques walking on a treadmill at different speeds and estimated three-dimensional angular motions of hindlimb and trunk segments, based on a model-based registration method. Our results demonstrated a considerable degree of axial rotation occurring at the trunk and hip joints during bipedal locomotion, suggesting that bipedal locomotion in Japanese macaques is essentially three-dimensional. In addition, ranges of angular motions at the hip and ankle joints were larger and the knee joint was more flexed in the mid-stance phase with increasing speed, indicating that gait kinematics are modulated depending on speed. Furthermore, macaques were confirmed to have actually acquired, at least to some extent, the energy conservation mechanism of walking due to pendular exchange of potential and kinetic energy, but effective utilization of this mutual exchange of energy was found to occur only at comparatively low velocity. Spring-like running mechanics were probably more exploited at higher speed because the duty factor was above 0.5. Fundamental differences in bipedal strategy seem to exist between human and non-human primate bipedal locomotion. PMID:20060569

Ogihara, Naomichi; Makishima, Haruyuki; Nakatsukasa, Masato

2010-01-08

346

Anatomically Plausible Surface Alignment and Reconstruction  

DEFF Research Database (Denmark)

With the increasing clinical use of 3D surface scanners, there is a need for accurate and reliable algorithms that can produce anatomically plausible surfaces. In this paper, a combined method for surface alignment and reconstruction is proposed. It is based on an implicit surface representation combined with a Markov Random Field regularisation method. Conceptually, the method maintains an implicit ideal description of the sought surface. This implicit surface is iteratively updated by realigning the input point sets and Markov Random Field regularisation. The regularisation is based on a prior energy that has earlier proved to be particularly well suited for human surface scans. The method has been tested on full cranial scans of ten test subjects and on several scans of the outer human ear.

Paulsen, Rasmus R.; Larsen, Rasmus

2010-01-01

347

Accuracy of distal radius positioning using an anatomical plate.  

UK PubMed Central (United Kingdom)

Over the past decade, several anatomical plates have been introduced to improve the result of open reduction and internal fixation of the distal radius. Using 3-dimensional imaging techniques, the authors studied the accuracy and reproducibility of distal radius positioning using anatomical plates.Distal radius fractures and the correction of these fractures were simulated with plastic bone models of radii. The authors simulated a defect by removing an arbitrary wedge shape from the artificial radii. Two surgeons corrected these fractures by placing 2 anatomical plate types according to the plate manufacturers' instructions. The residual positioning errors of the distal segment in relation to the unaffected radii were determined using 3-dimensional imaging and were compared with naturally occurring bilateral radius differences in healthy individuals. In many cases, positioning does not agree with differences based on bilateral asymmetry in healthy patients.This study indicated the accuracy of anatomical plates. Positioning an anatomical plate may lead to considerable residual errors in individual patients. Volar distal radius plate shapes differ among plate manufacturers. Therefore, one plate may perform better than another in an individual.

Vroemen JC; Dobbe JG; Sierevelt IN; Strackee SD; Streekstra GJ

2013-04-01

348

Technique for creating the anterior cruciate ligament femoral socket: optimizing femoral footprint anatomic restoration using outside-in drilling.  

UK PubMed Central (United Kingdom)

PURPOSE: The purpose of this study was to investigate and optimize anterior cruciate ligament (ACL) femoral outside-in drilling technique with a goal of anatomic restoration of the footprint morphologic length, width, area, and angular orientation. METHODS: Ex vivo, computer navigation was used to create virtual 3-dimensional maps of femoral bone tunnels for ACL drill guide pin insertion paths on small, medium, and large models of averaged femora considering various pin insertion angles to the femur. We then determined which pin insertion angle resulted in an ACL femoral footprint optimally matching normal human anatomic length, width, area, and angular orientation of the footprint long axis. RESULTS: During outside-in drilling of the ACL femoral socket, a guide pin entrance angle of 60° to a line perpendicular to the femoral anatomic axis, combined with a guide pin entrance angle of 20° to the transepicondylar axis, results in the closest approximation of the gold standard of normal anatomic morphology of the human knee ACL femoral footprint length, width, area, and angular orientation. CONCLUSIONS: During outside-in drilling of the ACL femoral socket, a guide pin entrance angle of 60° to a line perpendicular to the femoral anatomic axis, combined with a guide pin entrance angle of 20° to the transepicondylar axis, results in optimal reconstruction of the normal human anatomic ACL femoral footprint length, width, area, and angular orientation. CLINICAL RELEVANCE: We describe arthroscopic landmarks for anatomic ACL femoral socket creation that may be considered by practicing arthroscopic surgeons in the operating room, without open dissection or fluoroscopy and unaffected by type of drill guide or variations in the thickness of the femoral soft-tissue envelope.

Lubowitz JH; Akhavan S; Waterman BR; Aalami-Harandi A; Konicek J

2013-03-01

349

Angiosomes of the brachial plexus: an anatomical study.  

UK PubMed Central (United Kingdom)

This anatomical study analyzed the neurovascular relationships of the brachial plexus. Ten fresh cadaveric brachial plexuses were examined after injection of the arterial system. The vascular anatomical features of the brachial plexus were documented with microdissection after lead oxide/gelatin injection. The specimens were analyzed by using radiography (including digital subtraction techniques) and light-microscopic, macroscopic, and digital photography. Four angiosomes, based on the subclavian, axillary, vertebral, and dorsal scapular arteries, were observed. As noted in previous angiosome studies, connections between angiosome territories lay within tissues, in this case, nerve trunks. Nutrient vessels penetrated nerve trunks at points of branching within the brachial plexus, with a Y-shaped mode of division on entry. The vascular supply was markedly rich, often with true anastomotic connections occurring within the nerves. There was much variation in supply, depending on the vascular anatomical features of the subclavian artery.

Levy SM; Taylor GI; Baudet J; Guérin J; Casoli V; Pan WR; Houseman ND

2003-12-01

350

Electric field and current density distributions induced in an anatomically-based model of the human head by magnetic fields from a hair dryer  

Energy Technology Data Exchange (ETDEWEB)

We have used the impedance method to calculate the induced electric (E) fields and current densities (J) for the spatially varying vector magnetic fields due to a hair dryer. In this method, applicable for low-frequency exposures where the quasi-static approximation may be made, the biological body or the exposed parts thereof are represented by a three-dimensional (3-D) network of impedances whose individual values are obtained from the electrical properties {sigma}, {epsilon}{sub t} for the various tissues. We have measured the 3-D variations of the 50-Rz magnetic fields from a typical hair dryer and found that the various components correlate well with those for a helical coil. The non-uniform magnetic fields thus obtained are used to calculate the induced E and J with a resolution of 1.31 cm for the model of the head and neck. The induced E values are compared with the fields endogenous to the body and the minimum detectable E-field limits based on the cellular thermal noise model proposed Weaver and Astumian. 34 refs., 8 figs., 1 tab.

Tofani, S.; Ossola, P.; d`Amore, G. [Laboratorio di Sanita Pubblica, Ivrea (Italy)] [and others

1995-01-01

351

Automatic voxel-based morphometry of structural MRI by SPM8 plus diffeomorphic anatomic registration through exponentiated lie algebra improves the diagnosis of probable Alzheimer Disease.  

UK PubMed Central (United Kingdom)

BACKGROUND AND PURPOSE: The necessity for structural MRI is greater than ever to both diagnose AD in its early stage and objectively evaluate its progression. We propose a new VBM-based software program for automatic detection of early specific atrophy in AD. MATERIALS AND METHODS: A target VOI was determined by group comparison of 30 patients with very mild AD and 40 age-matched healthy controls by using SPM. Then this target VOI was incorporated into a newly developed automated software program independently running on a Windows PC for VBM by using SPM8 plus DARTEL. ROC analysis was performed for discrimination of 116 other patients with AD with very mild stage (n = 45), mild stage (n = 30) and moderate-to-advanced stages (n = 41) from 40 other age-matched healthy controls by using a z score map in the target VOI. RESULTS: Medial temporal structures involving the entire region of the entorhinal cortex, hippocampus, and amygdala showed significant atrophy in the patients with very mild AD and were determined as a target VOI. When we used the severity score of atrophy in this target VOI, 91.6%, 95.8%, and 98.2% accuracies were obtained in the very mild AD, mild AD, and moderate-to-severe AD groups, respectively. In the very mild AD group, a high specificity of 97.5% with a sensitivity of 86.4% was obtained, and age at onset of AD did not influence this accuracy. CONCLUSIONS: This software program with application of SPM8 plus DARTEL to VBM provides a high performance for AD diagnosis by using MRI.

Matsuda H; Mizumura S; Nemoto K; Yamashita F; Imabayashi E; Sato N; Asada T

2012-06-01

352

Multivariate models of inter-subject anatomical variability  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents a very selective review of some of the approaches for multivariate modelling of inter-subject variability among brain images. It focusses on applying probabilistic kernel-based pattern recognition approaches to pre-processed anatomical MRI, with the aim of most accurately modelli...

Ashburner, John; Klöppel, Stefan

353

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)

2010-01-01

354

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

355

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).

2008-10-07