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Anatomic Structures (anatomic + structure)
Selected AbstractsFetal anatomic survey using three-dimensional ultrasound in conjunction with first-trimester nuchal translucency screeningPRENATAL DIAGNOSIS, Issue 3 2010Mousumi Bhaduri Abstract Objective To determine the visualization rates of fetal anatomic structures by three-dimensional ultrasound (3DUS) at 12,13 weeks of gestation. Study Design This was a prospective observational study of women presenting for nuchal translucency ultrasound. Five 3D volumes of the fetus were acquired transabdominally. Two investigators independently reviewed the stored volumes offline following a standardized protocol. Results One hundred singleton fetuses were examined. The mean time for 3D volumes acquisition was 4.8 min; and for 3D review 17 min. Anatomic structures were seen as follows: cranium, lateral cerebral ventricles and abdominal wall 100%; stomach, vertebrae, upper and lower limbs , 94%; face 71%, bladder 58%, both kidneys 39%, skin overlying spine 26% and heart 18%. Agreement between two observers ranged from 100% (for head, abdominal wall and lower limbs) to 43% (for visualization of skin overlying spine). A complete basic anatomic survey was achieved in 11.4% of the 12-week fetuses and 33.3% of the 13-week fetuses (p -value = 0.038). Conclusions First-trimester transabdominal 3DUS was adequate for assessment of the head, abdominal wall, stomach, limbs and vertebral alignment. It was less effective for evaluating the heart and intactness of the skin over the spine. Copyright © 2010 John Wiley & Sons, Ltd. [source] Spatial independent component analysis of functional MRI time-series: To what extent do results depend on the algorithm used?HUMAN BRAIN MAPPING, Issue 3 2002Fabrizio Esposito Abstract Independent component analysis (ICA) has been successfully employed to decompose functional MRI (fMRI) time-series into sets of activation maps and associated time-courses. Several ICA algorithms have been proposed in the neural network literature. Applied to fMRI, these algorithms might lead to different spatial or temporal readouts of brain activation. We compared the two ICA algorithms that have been used so far for spatial ICA (sICA) of fMRI time-series: the Infomax (Bell and Sejnowski [1995]: Neural Comput 7:1004,1034) and the Fixed-Point (Hyvärinen [1999]: Adv Neural Inf Proc Syst 10:273,279) algorithms. We evaluated the Infomax- and Fixed Point-based sICA decompositions of simulated motor, and real motor and visual activation fMRI time-series using an ensemble of measures. Log-likelihood (McKeown et al. [1998]: Hum Brain Mapp 6:160,188) was used as a measure of how significantly the estimated independent sources fit the statistical structure of the data; receiver operating characteristics (ROC) and linear correlation analyses were used to evaluate the algorithms' accuracy of estimating the spatial layout and the temporal dynamics of simulated and real activations; cluster sizing calculations and an estimation of a residual gaussian noise term within the components were used to examine the anatomic structure of ICA components and for the assessment of noise reduction capabilities. Whereas both algorithms produced highly accurate results, the Fixed-Point outperformed the Infomax in terms of spatial and temporal accuracy as long as inferential statistics were employed as benchmarks. Conversely, the Infomax sICA was superior in terms of global estimation of the ICA model and noise reduction capabilities. Because of its adaptive nature, the Infomax approach appears to be better suited to investigate activation phenomena that are not predictable or adequately modelled by inferential techniques. Hum. Brain Mapping 16:146,157, 2002. © 2002 Wiley-Liss, Inc. [source] Conduction Characteristics at the Crista Terminalis During Onset of Pulmonary Vein Atrial FibrillationJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 8 2004SIMON P. FYNN M.D. Introduction: Focal atrial fibrillation (AF) may initiate with an irregular rapid burst of atrial ectopic (AE) activity from a pulmonary vein (PV) focus, but how AF is maintained it is not known. The crista terminalis (CT) is an important line of block in atrial flutter (AFL), but its role in AF has not been determined. The aim of this study was to examine the conduction properties of the CT during onset of AF. Methods and Results: In 10 patients (mean age 38 ± 8 years), we analyzed conduction across the CT during onset of focal AF from an arrhythmogenic PV and during pacing from the same PV at cycle lengths of 700 and 300 ms. A 20-pole catheter was positioned on the CT using intracardiac echocardiography. In 10 control patients with no history of AF, we analyzed conduction across the CT during pacing from the distal coronary sinus at 700 and 300 ms. In all 10 AF patients, AF was initiated with 1 to 9 AE beats (median 5) from a PV. During sinus rhythm, there were no split components (SC) recorded on the CT. During PV AE activity, discrete SC were recorded on the CT in all patients over 6.3 ± 0.9 bipoles (3.7 ± 0.3 cm). Maximal splitting of SC was 66 ± 31 ms (37,139). There was an inverse relationship between AE coupling intervals and the degree of splitting between SC in all patients. Degeneration to AF was preceded by progressive decrement across the CT. SC were recorded during PV pacing at 700 and 300 ms (maximal distance between SC of 24 ± 3 ms and 43 ± 5 ms, respectively, P < 0.001). Maximum SC at CT in controls was 13 ± 8 ms at 700 ms (P = 0.06 vs AF patients) and 16 ± 9 ms at 300 ms (P < 0.01 vs AF patients). Conclusion: (1) These observations provide evidence of anisotropic, decremental conduction across the CT during onset of focal AF and during pacing from the same PV. A line of functional conduction block develops along this anatomic structure (CT). Whether this line of block acts as an initiator of AF or simply contributes passively to nonuniform fibrillatory conduction is unknown. (2) In some patients with focal AF, development of conduction block along the CT may provide a substrate for typical AFL. [source] Functional neuroanatomy of the human pre-Bötzinger complex with particular reference to sudden unexplained perinatal and infant deathNEUROPATHOLOGY, Issue 1 2008Anna M. Lavezzi The authors are the first to identify in man the pre-Bötzinger complex, a structure of the brainstem critical for respiratory rhythmogenesis, previously investigated only in rats. The evaluation of the neurokinin 1 receptors and somatostatin immunoreactivity in a total of 63 brains from 25 fetuses, nine newborns and 29 infants, allowed to delineate the anatomic structure and the boundaries of this human neural center in a restricted area of the ventrolateral medulla at the obex level, ventral to the semicompact ambiguus nucleus. The neurons of the pre-Bötzinger complex were roundish in fetuses before 30 gestational weeks and lengthened after birth, embedded in a dendritic system belonging to the reticular formation. Besides, structural and/or functional alterations of the pre-Bötzinger complex were present in a high percentage of sudden deaths (47%), prevalent in late fetal deaths. In particular, different developmental defects (hypoplasia with a decreased neuronal number and/or dendritic hypodevelopment of the reticular formation, abnormal neuronal morphology, immunonegativity of neurotransmitters, and agenesis) were found. The authors suggest that the pre-Bötzinger complex contains a variety of neurons not only involved in respiratory rhythm generation, but more extensively, essential to the control of all vital functions. Sudden death and in particular sudden unexpected fetal death could therefore be ascribed to a selective process when developmental alterations of the pre-Bötzinger complex arise. [source] Importance of glutathione in the nodulation process of peanut (Arachis hypogaea)PHYSIOLOGIA PLANTARUM, Issue 2 2008Eliana Bianucci GSH appears to be essential for proper development of the root nodules during the symbiotic association of legume,rhizobia in which the entry of rhizobia involves the formation of infection threads. In the particular case of peanut,rhizobia symbiosis, the entry of rhizobia occurs by the mechanism of infection called ,crack entry', i.e. entry at the point of emergence of lateral roots. We have previously shown the role of GSH content of Bradyrhizobium sp. SEMIA 6144 during the symbiotic association with peanut using a GSH-deficient mutant obtained by disruption of the gshA gene, encoding ,-glutamylcysteine synthetase (,-GCS), which was able to induce nodules in peanut roots without alterations in the symbiotic phenotype. To investigate the role of the peanut GSH content in the symbiosis, the compound l -buthionine-sulfoximine (BSO), a specific inhibitor of ,-GCS in plants, was used. There were no differences in the plant growth and the typical anatomic structure of the peanut roots when the plants grew in the Fahraeus medium either in presence or in absence of 0.1 mM BSO. However, the GSH content was reduced by 51% after treatment with BSO. The BSO-treated plants inoculated with wild-type or mutant strains of Bradyrhizobium sp. showed a significant reduction in the number and dry weight of nodules, suggesting that GSH content could play an important role in the nodulation process of root peanut with Bradyrhizobium sp. [source] Classification of the External Auditory Canal CholesteatomaTHE LARYNGOSCOPE, Issue 3 2005Ramin Naim Abstract Objectives/Hypothesis: The external auditory canal cholesteatoma (EACC) is a rare disease in the field of otolaryngology. Only 1 in 1,000 new otologic patients present with this entity, which was first described by Toynbee. The aim of this article is to classify EACC by different histopathologic and clinical findings of patients presenting to the Department of Otolaryngology at the University of Mannheim, Germany. Methods: From 2000 to 2004, 17 patients presented to our clinic with EACC. The cholesteatoma were treated surgically, and the specimens were investigated histologically. Clinical findings were also recorded. We classified four stages: stage I with hyperplasia of the canal epithelium, stage II including periosteitis, Stage III including a defective bony canal, and stage IV showing an erosion of adjacent anatomic structure. Results: Eight patients presented with stage II, five patients with stage III, three with stage I, and only one patient presented with erosion of the mastoid cells, which was determined as stage IV. Conclusion: In summary, our classification serves to describe the different histopathologic and clinical stages of EACC. [source] Dynamic morphological changes in the skulls of mice mimicking human Apert syndrome resulting from gain-of-function mutation of FGFR2 (P253R)JOURNAL OF ANATOMY, Issue 2 2010Xiaolan Du Abstract Apert syndrome is caused mainly by gain-of-function mutations of fibroblast growth factor receptor 2. We have generated a mouse model (Fgfr2+/P253R) mimicking human Apert syndrome resulting from fibroblast growth factor receptor 2 Pro253Arg mutation using the knock-in approach. This mouse model in general has the characteristic skull morphology similar to that in humans with Apert syndrome. To characterize the detailed changes of form in the overall skull and its major anatomic structures, euclidean distance matrix analysis was used to quantitatively compare the form and growth difference between the skulls of mutants and their wild-type controls. There were substantial morphological differences between the skulls of mutants and their controls at 4 and 8 weeks of age (P < 0.01). The mutants showed shortened skull dimensions along the rostrocaudal axis, especially in their face. The width of the frontal bone and the distance between the two orbits were broadened mediolaterally. The neurocrania were significantly increased along the dorsoventral axis and slightly increased along the mediolateral axis, and also had anteriorly displayed opisthion along the rostrocaudal axis. Compared with wild-type, the mutant mandible had an anteriorly displaced coronoid process and mandibular condyle along the rostrocaudal axis. We further found that there was catch-up growth in the nasal bone, maxilla, zygomatic bone and some regions of the mandible of the mutant skulls during the 4,8-week interval. The above-mentioned findings further validate the Fgfr2+/P253R mouse strain as a good model for human Apert syndrome. The changes in form characterized in this study will help to elucidate the mechanisms through which the Pro253Arg mutation in fibroblast growth factor receptor 2 affects craniofacial development and causes Apert syndrome. [source] Reentry in a Morphologically Realistic Atrial ModelJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 9 2001EDWARD J. VIGMOND Ph.D. Reentry in Morphologically Realistic Atria.Introduction: Atrial fibrillation is the most common cardiac arrhythmia. In ablation procedures, identification of the reentrant pathways is vital. This has proven difficult because of the complex morphology of the atria. The purpose of this study was to ascertain the role of specific anatomic structures on reentry induction and maintenance. Method and Results: A computationally efficient, morphologically realistic, computer model of the atria was developed that incorporates its major structural features, including discrete electrical connections between the right and left atria, physiologic fiber orientation in three dimensions, muscle structures representing the crista terminalis (CT) and pectinate muscles, and openings for the veins and AV valves. Reentries were induced near the venous openings in the left and right atria, the mouth of the coronary sinus, and the free wall of the right atrium. The roles of certain muscular structures were ascertained by selectively removing the structures and observing how the propagation of activity was affected. Conclusion: (1) The muscular sheath of the coronary sinus acts as a pathway for a reentrant circuit and stabilizes any circuits that utilize the isthmus near the inferior vena cava. (2) Poor trans-CT coupling serves to stabilize flutter circuits. (3) Wall thickness is an important factor in the propagation of electrical activity, especially in the left atrium. (4) The openings of the inferior and superior venae cavae form natural anatomic anchors that make reentry easier to initiate by allowing for smaller ectopic beats to induce reentry. [source] Concurrence Between the Maxillary Midline and Bisector to the Interpupillary LineJOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY, Issue 1 2009EVANIA ESKELSEN DDS ABSTRACT Purpose:, Symmetry is one of the factors that contributes to facial harmony, and in oral rehabilitation it determines the success of esthetic treatment. Therefore, the aim of the present study was to analyze the axial symmetry between the bipupillar midline and maxillary central incisors midline of 102 dental students (both genders) distributed across five Brazilian dental schools. Materials and Methods:, Students with no teeth missing and who had never been subjected to any dental treatment were selected. Photographs were taken with a Dental Eye III camera with a 100-mm macro objective and ratio of 1 : 10 from natural size, recorded on an Ektachrome ASA/ISO 100 film. The images were developed and applied to Microsoft Office Power Point 2007 software. The results were analyzed by analysis of variance and Student's t -test (, = 0.05). Results:, There was no significant correlation between bipupillar midline and the maxillary dental midline, irrespective of gender. Conclusion:, No significant coincidence was observed between the interpupillary and dental midline. However, the interpupillar distance and its relationship with other anatomic structures may be used as a reference in treatment, but measurements must be assessed individually. CLINICAL SIGNIFICANCE Anatomic measurements and facial proportions can be helpful during the planning of esthetic oral rehabilitation. [source] Impact of a regional anesthesia rotation on ultrasonographic identification of anatomic structures by anesthesiology residentsACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 3 2009S. L. OREBAUGH Objective: The specific aim of this study was to determine the ability of anesthesiology residents to independently identify a series of anatomic structures in a live model using ultrasound, both before and after a 4-week regional anesthesia rotation that incorporates a standardized ultrasound training curriculum for peripheral nerve blockade. Methods: Ten CA2 and CA3 anesthesiology residents volunteered to participate in this study. Each resident was subjected to a pre-rotation practical exam, in which he attempted to identify 15 structures at four sites of peripheral nerve blockade, in a test subject. Each resident then received specific training for ultrasound-guided nerve blocks during a 4-week regional anesthesia rotation, and then completed a post-rotation exam. The mean number of structures correctly identified on the exams was compared for significant differences utilizing a paired t -test. Results: Residents were able to identify significantly more anatomic structures on the post-rotation exam as compared with the pre-rotation exam (mean 14.1 vs. 9.9, P<.001), as well as more peripheral nerve targets. The most frequently misidentified structures on the pre-rotation exam were the subclavian vein, the sciatic nerve in the popliteal fossa, and the femur. Conclusions: Ultrasound-naïve anesthesiology residents, who received instruction and experience with ultrasound-guided peripheral nerve blocks on a 4-week regional anesthesia rotation, significantly improved their ability to independently identify relevant anatomic structures with ultrasonography. [source] Popliteal artery entrapment syndrome: Non-invasive diagnosis by MDCT and MRIJOURNAL OF MEDICAL IMAGING AND RADIATION ONCOLOGY, Issue 2007D Utsunomiya SUMMARY We present a case of a 19-year-old male patient complaining of right leg pain, which appeared after exercise and abated with rest. Computed tomography (CT) and magnetic resonance angiography (MRA) showed occlusion of right popliteal artery. Volume rendering CT image showed not only occlusion of right popliteal artery but also abnormal course of the medial head of the gastrocnemius muscle (MHG). CT and MR images of right popliteal fossa showed the abnormal anatomy that MHG coursed between popliteal artery with thrombus and popliteal vein. Popliteal artery entrapment syndrome was diagnosed non-invasively by multidetector CT and MRI. Sectional radiological and three-dimensional images are useful for not only depiction of the arterial changes but also identification of the abnormal anatomic structures responsible for the entrapment. [source] Fetal anatomic survey using three-dimensional ultrasound in conjunction with first-trimester nuchal translucency screeningPRENATAL DIAGNOSIS, Issue 3 2010Mousumi Bhaduri Abstract Objective To determine the visualization rates of fetal anatomic structures by three-dimensional ultrasound (3DUS) at 12,13 weeks of gestation. Study Design This was a prospective observational study of women presenting for nuchal translucency ultrasound. Five 3D volumes of the fetus were acquired transabdominally. Two investigators independently reviewed the stored volumes offline following a standardized protocol. Results One hundred singleton fetuses were examined. The mean time for 3D volumes acquisition was 4.8 min; and for 3D review 17 min. Anatomic structures were seen as follows: cranium, lateral cerebral ventricles and abdominal wall 100%; stomach, vertebrae, upper and lower limbs , 94%; face 71%, bladder 58%, both kidneys 39%, skin overlying spine 26% and heart 18%. Agreement between two observers ranged from 100% (for head, abdominal wall and lower limbs) to 43% (for visualization of skin overlying spine). A complete basic anatomic survey was achieved in 11.4% of the 12-week fetuses and 33.3% of the 13-week fetuses (p -value = 0.038). Conclusions First-trimester transabdominal 3DUS was adequate for assessment of the head, abdominal wall, stomach, limbs and vertebral alignment. It was less effective for evaluating the heart and intactness of the skin over the spine. Copyright © 2010 John Wiley & Sons, Ltd. [source] Computed Tomographic, Magnetic Resonance Imaging, and Cross-Sectional Anatomic Features of the Manus in a Normal American Black Bear (Ursus americanus)ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 3 2010C. P. Ober With 11 figures and 1 table Summary The purpose of this study was to provide a detailed description of cross-sectional anatomic structures of the manus of a black bear cadaver and correlate anatomic findings with corresponding features in computed tomographic (CT) and magnetic resonance (MR) images. CT, MR imaging, and transverse sectioning were performed on the thoracic limb of a cadaver female black bear which had no evidence of lameness or thoracic limb abnormality prior to death. Features in CT and MR images corresponding to clinically important anatomic structures in anatomic sections were identified. Most of the structures identified in transverse anatomic sections were also identified using CT and MR imaging. Bones, muscles and tendons were generally easily identified with both imaging modalities, although divisions between adjacent muscles were rarely visible with CT and only visible sometimes with MR imaging. Vascular structures could not be identified with either imaging modality. [source] CT-Soft Tissue Window of the Cranial Abdomen in Clinically Normal Dogs: An Anatomical description using Macroscopic Cross-Sections with Vascular InjectionANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 1 2009M. A. Rivero Summary The aim of this study was to provide a detailed anatomic atlas of the cranial abdomen by means of computed tomography (CT). Three mature dogs, all mixed breed males, were used. The dogs were sedated, anaesthetized and positioned in sternal recumbency. CT scans from the eighth thoracic vertebra to the fourth lumbar vertebra were performed using a third-generation equipment (TOSHIBA 600HQ scanner) with 1 cm slice thickness. CT-images of the cranial abdomen were taken with soft-tissue window (WL: ,14, WW: 658) settings. Dogs were killed and vascular-injection technique was performed: red and blue latex filled the vascular system. Injected dogs were frozen in the same position as used for CT examination and sectioned with an electric bandsaw at 1-cm-thick intervals. The cuts matched as closely as possible to the CT-images. The anatomic sections were compared and studied with the corresponding CT-images, and clinically relevant abdominal anatomic structures were identified and labelled on the corresponding CT-images. The results of our study could be used as a reference for evaluating CT-images of the canine cranial abdomen with abdominal diseases. [source] CT and Cross-sectional Anatomy of the Normal Head of the Loggerhead Sea Turtle (Caretta caretta)ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 2005A. Arencibia The objective of this study is to describe the CT anatomy of the normal loggerhead sea turtle (Caretta caretta) head using three loggerhead sea turtle heads. CT imaging was performed using the following parameters: K.v.: 120 mAs: 220, and a soft-tissue window (WW 1880, WL 465): Transverse and sagittal CT images were obtained. Detailed anatomy of the head was acquired with the sagittal and transverse series. The heads were frozen and then sectioned using an electric saw, to compare them with the CT images. In CT, the grey scale is directly related to the radiation attenuation of the head structures. The skull and hyoid bones, and the lower jaw were easily identifiable due to the high CT density image compared to adjacent or surrounding structures such as the respiratory system, oral cavity, oesophagus and cranial cavity that appeared as a low opacity. The nervous structures, salt gland, eyeball, ramphoteca structure and different muscles of the head had an intermediate CT density and appeared grey. CT images of the loggerhead sea turtle head provided excellent detail of clinically relevant anatomy and correlated well with corresponding gross specimens. CT of the head has considerable advantages over other techniques: CT provides excellent spatial resolution and good discrimination between bone and soft tissue, and the structures are viewed without superimposition. The planimetric or sectional anatomy of the head allows a correct morphologic and topographic evaluation of the anatomic structures, which is a useful tool for the identification of the CT images. With developing technology, CT imaging may soon become more readily available for exotic animals imaging. In the same way, we consider it quite useful to be able to establish some references on head, in order to scan only selected parts during a clinical or experimental approach. The information presented in this communication should serve as an initial reference to evaluate CT images of the loggerhead sea turtle head and to assist interpretation of lesions of this region. [source] Clinical Assessment and Surgical Implications of Anatomic Challenges in the Anterior MandibleCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 4 2003Nuri Mraiwa BDS ABSTRACT Background: The anterior mandible is generally considered a rather safe surgical area, involving few risks of damage to vital anatomic structures. Nevertheless, both neurosensory disturbances and hemorrhages have been reported after implant surgery in that particular area. Purpose: With the increasing demand for oral implant placement, the anatomy of the anterior mandible should receive more attention. This review will focus on the anatomic peculiarities of the anterior mandible and the related clinical implications. Methods: The scientific evidence on the anatomic, histologic, physiologic, and clinical aspects of the neurovascularization of the anterior mandible will be reviewed. Results: Surgical complications may be attributed to the existence of a mandibular incisive canal with a true neurovascular supply. Potential risks may also be related to the presence of the lingual foramen and anatomic variations, such as an anterior looping of the mental nerve. Conclusions: Preoperative radiographic planning for oral implant placement in the anterior mandible should therefore not only consider all esthetic and functional demands but should also pay particular attention to the anatomic peculiarities of this region to avoid any neurovascular complications. [source] | |||||||||||||