scholarly journals Multi-Atlas MRI-Based Striatum Segmentation for 123I-FP-CIT SPECT (DAT-SPECT) Compared With the Bolt Method and SPECT-Atlas-Based Segmentation Method Toward the Accurate Diagnosis of Parkinson's Disease/Syndrome

2021 ◽  
Vol 8 ◽  
Author(s):  
Koji Sohara ◽  
Tetsuro Sekine ◽  
Amane Tateno ◽  
Sunao Mizumura ◽  
Masaya Suda ◽  
...  
Keyword(s):  
Healthy Volunteers ◽  
Healthy Subjects ◽  
Occipital Lobe ◽  
Occipital Cortex ◽  
Accurate Diagnosis ◽  
Reference Region ◽  
Uptake Ratio ◽  
Segmentation Method ◽  
Clinical Methods ◽  
Dat Spect

Aims: This study aimed to analyze the performance of multi-atlas MRI-based parcellation for 123I-FP-CIT SPECT (DAT-SPECT) in healthy volunteers. The proposed method was compared with the SPECT-atlas-based and Bolt methods. 18F-FE-PE2I-PET (DAT-PET) was used as a reference.Methods: Thirty healthy subjects underwent DAT-SPECT, DAT-PET, and 3D-T1WI-MRI. We calculated the striatum uptake ratio (SUR/SBR), caudate uptake ratio (CUR), and putamen uptake ratio (PUR) for DAT-SPECT using the multi-atlas MRI-based method, SPECT-atlas-based method, and Bolt method. In the multi-atlas MRI-based method, the cerebellum, occipital cortex, and whole-brain were used as reference regions. The correlation of age with DAT-SPECT activity and the correlations of SUR/SBR, CUR, and PUR between DAT-SPECT and DAT-PET were calculated by each of the three methods.Results: The correlation between age and SUR/SBR for DAT-SPECT based on the multi-atlas MRI-based method was comparable to that based on the SPECT-atlas-based method (r = −0.441 to −0.496 vs. −0.488). The highest correlation between DAT-SPECT and DAT-PET was observed using the multi-atlas MRI-based method with the occipital lobe defined as the reference region compared with the SPECT-atlas-based and Bolt methods (SUR, CUR, and PUR: 0.687, 0.723, and 0.676 vs. 0.698, 0.660, and 0.616 vs. 0.655).Conclusion: Multi-atlas MRI-based parcellation with the occipital lobe defined as the reference region was at least comparable to the clinical methods.

scholarly journals The use of a neck brace does not influence visual vertical perception

2011 ◽  
Vol 69 (3) ◽  
pp. 509-512 ◽  
Author(s):  
Martha Funabashi ◽  
Natya N.L. Silva ◽  
Luciana M. Watanabe ◽  
Taiza E.G Santos-Pontelli ◽  
José Fernando Colafêmina ◽  
...  
Keyword(s):  
Healthy Volunteers ◽  
Healthy Subjects ◽  
Afferent Input ◽  
Subjective Visual Vertical ◽  
Sensory Receptors ◽  
Ocular Torsion ◽  
Vertical Orientation ◽  
Mean Values ◽  
Visual Vertical ◽  
The Mean

Subjective visual vertical (SVV) evaluates the individual's capacity to determine the vertical orientation. Using a neck brace (NB) allow volunteers' heads fixation to reduce cephalic tilt during the exam, preventing compensatory ocular torsion and erroneous influence on SVV result. OBJECTIVE: To analyze the influence of somatosensory inputs caused by a NB on the SVV. METHOD: Thirty healthy volunteers performed static and dynamic SVV: six measures with and six without the NB. RESULTS: The mean values for static SVV were -0.075º±1.15º without NB and -0.372º±1.21º with NB. For dynamic SVV in clockwise direction were 1.73º±2.31º without NB and 1.53º±1.80º with NB. For dynamic SVV in counterclockwise direction was -1.50º±2.44º without NB and -1.11º±2.46º with NB. Differences between measurements with and without the NB were not statistically significant. CONCLUSION: Although the neck has many sensory receptors, the use of a NB does not provide sufficient afferent input to change healthy subjects' perception of visual verticality.

Increased frequency of aberrant CSF circulation in schizophrenic patients compared to healthy volunteers

1996 ◽  
Vol 11 (1) ◽  
pp. 16-20 ◽  
Author(s):  
G Oxenstierna ◽  
G Bergstrand ◽  
G Edman ◽  
L Flyckt ◽  
H Nybäck ◽  
...  
Keyword(s):  
Healthy Volunteers ◽  
Healthy Subjects ◽  
Flow Dynamics ◽  
Resonance Imaging ◽  
Improved Method ◽  
Csf Circulation ◽  
Recent Developments ◽  
Schizophrenic Patients ◽  
Duration Of Disease ◽  
Csf Levels

SummaryIn a previous cisternographic study of the cerebrospinal fluid (CSF) circulation in schizophrenic patients, indications for disturbed flow dynamics were found in 10 of 30 subjects. In order to replicate and investigate the clinical and pathophysiological significance of this finding, 39 schizophrenic patients and 42 healthy subjects were examined with an improved method for measurement of CSF circulation. 99mTc-DTPA was injected intrathecally and the gamma cisternograms were evaluated blindly. Correlations between cisternography findings and age, duration of disease, previous hospitalizations, positive or negative symptomatology, exposure to neuroleptics, psychiatric family history, CT findings and CSF levels of protein, tryptophan and monoamine metabolites, were calculated. Seven of the patients showed abnormalities in the cisternograms with a slow or obstructed flow of CSF over the convexities (P < 0.01) whereas none of the healthy volunteers showed abnormalities. There were no correlations between disturbed CSF circulation in the patients and the clinical and biochemical parameters, thus the significance of the deviations, similar to other biological aberrations found in schizophrenic patients, is not known. Recent developments in magnetic resonance imaging offer new possibilities to further examine CSF circulation abnormalities in schizophrenia.

scholarly journals Safety, pharmacokinetics, and reversal of apixaban anticoagulation with andexanet alfa

2017 ◽  
Vol 1 (21) ◽  
pp. 1827-1838 ◽  
Author(s):  
Deborah Siegal ◽  
Genmin Lu ◽  
Janet M. Leeds ◽  
Mark Karbarz ◽  
Janice Castillo ◽  
...  
Keyword(s):  
Healthy Volunteers ◽  
Healthy Subjects ◽  
Preclinical Models ◽  
Key Points ◽  
Andexanet Alfa

Key Points Andexanet reversed apixaban anticoagulation in healthy volunteers within minutes after administration and for the duration of infusion. Andexanet was generally well tolerated, with no evidence of prothrombotic activity in preclinical models and in healthy subjects.

scholarly journals Exhaled Breath Condensate: Pilot Study of the Method and Initial Experience in Healthy Subjects

2018 ◽  
Vol 61 (1) ◽  
pp. 8-16
Author(s):  
Eva Peterová ◽  
Jaroslav Chládek ◽  
Darina Kohoutová ◽  
Veronika Knoblochová ◽  
Paula Morávková ◽  
...  
Keyword(s):  
Pilot Study ◽  
Healthy Volunteers ◽  
Coefficient Of Variation ◽  
Healthy Subjects ◽  
Lung Diseases ◽  
Exhaled Breath Condensate ◽  
Exhaled Breath ◽  
Initial Experience ◽  
Major Disadvantage ◽  
Breath Condensate

Analysis of Exhaled breath condensate (EBC) is a re-discovered approach to monitoring the course of the disease and reduce invasive methods of patient investigation. However, the major disadvantage and shortcoming of the EBC is lack of reliable and reproducible standardization of the method. Despite many articles published on EBC, until now there is no clear consensus on whether the analysis of EBC can provide a clue to diagnosis of the diseases. The purpose of this paper is to investigate our own method, to search for possible standardization and to obtain our own initial experience. Thirty healthy volunteers provided the EBC, in which we monitored the density, pH, protein, chloride and urea concentration. Our results show that EBC pH is influenced by smoking, and urea concentrations are affected by the gender of subjects. Age of subjects does not play a role. The smallest coefficient of variation between individual volunteers is for density determination. Current limitations of EBC measurements are the low concentration of many biomarkers. Standardization needs to be specific for each individual biomarker, with focusing on optimal condensate collection. EBC analysis has a potential become diagnostic test, not only for lung diseases.

Combining fiber tracking and functional brain imaging for revealing brain networks involved in auditory–visual integration in humans

2012 ◽  
Vol 25 (0) ◽  
pp. 5 ◽  
Author(s):  
Anton L. Beer ◽  
Tina Plank ◽  
Evangelia-Regkina Symeonidou ◽  
Georg Meyer ◽  
Mark W. Greenlee
Keyword(s):  
White Matter ◽  
Functional Activity ◽  
Occipital Lobe ◽  
Object Perception ◽  
Occipital Cortex ◽  
Fiber Tracking ◽  
Visual Object ◽  
Body Movements ◽  
Body Area ◽  
Probabilistic Tracking

Previous functional magnetic resonance imaging (MRI) found various brain areas in the temporal and occipital lobe involved in integrating auditory and visual object information. Fiber tracking based on diffusion-weighted MRI suggested neuroanatomical connections between auditory cortex and sub-regions of the temporal and occipital lobe. However, the relationship between functional activity and white-matter tracks remained unclear. Here, we combined probabilistic tracking and functional MRI in order to reveal the structural connections related to auditory–visual object perception. Ten healthy people were examined by diffusion-weighted and functional MRI. During functional examinations they viewed either movies of lip or body movements, listened to corresponding sounds (phonological sounds or body action sounds), or a combination of both. We found that phonological sounds elicited stronger activity in the lateral superior temporal gyrus (STG) than body action sounds. Body movements elicited stronger activity in the lateral occipital cortex than lip movements. Functional activity in the phonological STG region and the lateral occipital body area were mutually modulated (sub-additive) by combined auditory–visual stimulation. Moreover, bimodal stimuli engaged a region in the posterior superior temporal sulcus (STS). Probabilistic tracking revealed white-matter tracks between the auditory cortex and sub-regions of the STS (anterior and posterior) and occipital cortex. The posterior STS region was also found to be relevant for auditory–visual object perception. The anterior STS region showed connections to the phonological STG area and to the lateral occipital body area. Our findings suggest that multisensory networks in the temporal lobe are best revealed by combining functional and structural measures.

scholarly journals Visual hallucinations in Alzheimer's disease do not seem to be associated with chronic hypoperfusion of to visual processing areas V2 and V3 but may be associated with reduced cholinergic input to these areas

2019 ◽  
Vol 11 (1) ◽  
Author(s):  
Lindsey Isla Sinclair ◽  
Amit Kumar ◽  
Taher Darreh-Shori ◽  
Seth Love
Keyword(s):  
Microvessel Density ◽  
Visual Processing ◽  
Occipital Lobe ◽  
Occipital Cortex ◽  
Cholinergic Innervation ◽  
Density Level ◽  
Post Mortem ◽  
Visual Hallucinations ◽  
Metabolic Demand ◽  
Cell Content

Abstract Background Up to 20% of patients with AD experience hallucinations. The pathological substrate is not known. Visual hallucinations (VH) are more common in dementia with Lewy bodies (DLB). In autopsy studies, up to 60% of patients with AD have concomitant Lewy body pathology. Decreased perfusion of the occipital lobe has been implicated in DLB patients with VH, and post-mortem studies point to both decreased cholinergic activity and reduced oxygenation of the occipital cortex in DLB. Methods We used biochemical methods to assess microvessel density (level of von Willebrand factor, a marker of endothelial cell content), ante-mortem oxygenation (vascular endothelial growth factor, a marker of tissue hypoxia; myelin-associated glycoprotein to proteolipid protein-1 ratio, a measure of tissue oxygenation relative to metabolic demand), cholinergic innervation (acetylcholinesterase and choline acetyltransferase), butyrylcholinesterase and insoluble α-synuclein content in the BA18 and BA19 occipital cortex obtained post-mortem from 23 AD patients who had experienced visual hallucinations, 19 AD patients without hallucinations, 19 DLB patients, and 36 controls. The cohorts were matched for age, gender and post-mortem interval. Results There was no evidence of reduced microvessel density, hypoperfusion or reduction in ChAT activity in AD with visual hallucinations. Acetylcholinesterase activity was reduced in both BA18 and BA19, in all 3 dementia groups, and the concentration was also reduced in BA19 in the DLB and AD without visual hallucinations groups. Insoluble α-synuclein was raised in the DLB group in both areas but not in AD either with or without visual hallucinations. Conclusions Our results suggest that visual hallucinations in AD are associated with cholinergic denervation rather than chronic hypoperfusion or α-synuclein accumulation in visual processing areas of the occipital cortex.

Is Occipital Cortex a Valid Reference Region in 123I-FP-CIT SPECT Imaging?

2015 ◽  
Vol 40 (7) ◽  
pp. 615-616 ◽  
Author(s):  
Juho Joutsa ◽  
Jarkko Johansson ◽  
Valtteri Kaasinen
Keyword(s):  
Occipital Cortex ◽  
Spect Imaging ◽  
Reference Region

CHANGES IN THYROXINE-BINDING GLOBULIN LEVELS IN THYROTOXICOSIS AND IN HEALTHY SUBJECTS AFTER TRIIODOTHYRONINE ADMINISTRATION

1970 ◽  
Vol 63 (3) ◽  
pp. 527-532 ◽  
Author(s):  
R. F. Harvey ◽  
E. S. Williams ◽  
S. Ellis ◽  
R. P. Ekins
Keyword(s):  
Healthy Volunteers ◽  
Healthy Subjects ◽  
Intramuscular Injection ◽  
Thyroid Stimulating Hormone ◽  
Thyroxine Binding Globulin ◽  
Consistent Effect ◽  
Stimulating Hormone

ABSTRACT Thyroxine-binding globulin (TBG) levels were found to be significantly lower in 40 thyrotoxic patients than in 70 healthy subjects. A similar mean fall in TBG of 18% was produced by administration of 'physiological' doses of triiodothyronine to healthy volunteers. However, intramuscular injection of thyroid-stimulating hormone (TSH) had no consistent effect on the level of TBG as measured up to 4 days after injection. These findings are believed to explain the anomalous results described by earlier workers. It is suggested that TBG concentration is regulated by unknown mechanisms subject to the influence of many hormones, including triiodothyronine.

scholarly journals Human V4 and ventral occipital retinotopic maps

2015 ◽  
Vol 32 ◽  
Author(s):  
JONATHAN WINAWER ◽  
NATHAN WITTHOFT
Keyword(s):  
Occipital Lobe ◽  
Occipital Cortex ◽  
Ventral Surface ◽  
Anatomical Landmarks ◽  
Retinotopic Maps ◽  
Visual Encoding ◽  
Retinotopic Organization ◽  
History Of ◽  
The Subject

AbstractThe ventral surface of the human occipital lobe contains multiple retinotopic maps. The most posterior of these maps is considered a potential homolog of macaque V4, and referred to as human V4 (“hV4”). The location of the hV4 map, its retinotopic organization, its role in visual encoding, and the cortical areas it borders have been the subject of considerable investigation and debate over the last 25 years. We review the history of this map and adjacent maps in ventral occipital cortex, and consider the different hypotheses for how these ventral occipital maps are organized. Advances in neuroimaging, computational modeling, and characterization of the nearby anatomical landmarks and functional brain areas have improved our understanding of where human V4 is and what kind of visual representations it contains.

Ex-Vivo Assessments in the Evaluation of Dose Response to Recombinant Factor VIIa When Administered for Bleeding Following Punch Biopsies in Healthy Volunteers.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4055-4055
Author(s):  
Don A. Gabriel ◽  
Brett E. Skolnick ◽  
Philip Leese ◽  
David Mathews
Keyword(s):  
Blood Loss ◽  
Healthy Volunteers ◽  
Dose Response ◽  
Healthy Subjects ◽  
Ex Vivo ◽  
Punch Biopsy ◽  
Safety Issues ◽  
Part C ◽  
Hemostatic Agents ◽  
Blood Loss Volume

Abstract The utility of existing methods for the evaluation of hemostatic agents has been limited. The purpose of this study was to evaluate and optimize the use of a standardized punch biopsy to investigate the effects of hemostatic agents in healthy subjects. Recombinant FVIIa (rFVIIa) is licensed for the treatment of bleeding episodes in patients with hemophilia A or B with inhibitors. Recent reports (anecdotal and from randomized clinical trials) have described the successful use of rFVIIa in patients with liver disease, intracerebral hemorrhage, congenital and acquired coagulation factor deficiency, warfarin-induced bleeding, thrombocytopenia, traumatic brain injury, spinal cord surgery, and platelet disorders using a wide range of doses and dosing regimens. This variety of clinical situations, suggests a need to determine the optimal dose and dosing regime of rFVIIa for use in these potentially new therapeutic areas. A study was designed to evaluate the dose-response of rFVIIa in a controlled manner using a punch biopsy procedure in healthy volunteers that consented to participate in an IRB approved protocol. The study was designed as a three-part trial. Part A (6 subjects) optimized the size of the biopsy needed to create bleeding times and durations appropriate for study purposes. Part B (10 subjects) determined the feasibility of evaluating rFVIIa efficacy and safety in this bleeding model. Part C (48 subjects) examined, in an ascending dose escalation paradigm, the effect of a single dose of rFVIIa on bleeding time, blood loss volume, coagulation parameters and coagulation status in healthy volunteers. In Part C, all patients underwent three punch biopsies: the first (baseline biopsy) with no treatment, the second with either a low or high rFVIIa dose administered prior to biopsy, the third with either a low or high dose of rFVIIa administered prior to biopsy. The treatment pair sequences were placebo/10, 10/20, 20/40, 40/80, 80/120, and 120/160 μg/kg. Blood samples were drawn 15 minutes pre-, 15 minutes post-, and 1 hour post-biopsy to monitor coagulation and conduct ex-vivo assessments of hemostasis [Hemodyne Hemostasis Analyzer (HHA)]. Safety evaluations were conducted by an Independent Safety Officer after each dose tier, and subjects were permitted to enroll in the next higher dose tier only if no significant safety issues were observed. In healthy subjects with no pre-existing coagulopathies, regression analyses indicated that increasing doses of rFVIIa did not have a dose-related linear effect on blood loss volume or duration of bleeding. However, it is of interest that with HHA, a statistically significant impact was noted on the time to 20 mm clot strength, platelet contractile force, and clot elastic modulus, suggesting that rFVIIa does have a measureable and perhaps meaningful effect in individuals with normal coagulation systems. No safety issues were detected during this study. Thus in this model system, designed to evaluate hemostasis, interesting effects were seen with the HHA instrument which suggest that increasing doses of rFVIIa may impact clot stability, but these observations are limited by the significant hetereogeneity which may benefit from improved experimental controls.

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