Heterogeneity of Cerebral Blood Flow: a Fractal Approach

2000 ◽  
Vol 39 (02) ◽  
pp. 37-42 ◽  
Author(s):  
P. Hartikainen ◽  
J. T. Kuikka
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Fractal Dimension ◽  
Frontal Lobe ◽  
Fractal Analysis ◽  
Relative Dispersion ◽  
Emission Computed Tomography ◽  
Brain Blood Flow ◽  
Healthy Controls ◽  
Fractal Approach

Summary Aim: We demonstrate the heterogeneity of regional cerebral blood flow using a fractal approach and singlephoton emission computed tomography (SPECT). Method: Tc-99m-labelled ethylcysteine dimer was injected intravenously in 10 healthy controls and in 10 patients with dementia of frontal lobe type. The head was imaged with a gamma camera and transaxial, sagittal and coronal slices were reconstructed. Two hundred fifty-six symmetrical regions of interest (ROIs) were drawn onto each hemisphere of functioning brain matter. Fractal analysis was used to examine the spatial heterogeneity of blood flow as a function of the number of ROIs. Results: Relative dispersion (= coefficient of variation of the regional flows) was fractal-like in healthy subjects and could be characterized by a fractal dimension of 1.17 ± 0.05 (mean ± SD) for the left hemisphere and 1.15 ± 0.04 for the right hemisphere, respectively. The fractal dimension of 1.0 reflects completely homogeneous blood flow and 1.5 indicates a random blood flow distribution. Patients with dementia of frontal lobe type had a significantly lower fractal dimension of 1.04 ± 0.03 than in healthy controls. Conclusion: Within the limits of spatial resolution of SPECT, the heterogeneity of brain blood flow is well characterized by a fractal dimension. Fractal analysis may help brain scientists to assess age-, sex- and laterality-related anatomic and physiological changes of brain blood flow and possibly to improve precision of diagnostic information available for patient care.

scholarly journals Regional Cerebral Blood Flow Abnormalities in Neurosyphilis: A Pilot SPECT Study

2021 ◽  
Vol 12 ◽  
Author(s):  
Jooyeon J. Im ◽  
Hyeonseok Jeong ◽  
Young Do Kim ◽  
Kyung-Sool Jang ◽  
In-Uk Song ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Regional Cerebral Blood Flow ◽  
Photon Emission ◽  
Case Series ◽  
Emission Computed Tomography ◽  
Healthy Controls ◽  
Regional Cerebral Blood ◽  
Clinical Dementia Rating ◽  
Posterior Cingulate

Objective: Clinical and radiological findings on neurosyphilis are fairly non-specific and there is a paucity of functional neuroimaging studies on neurosyphilis other than case reports and case series. The purpose of this study was to investigate brain perfusion abnormalities in patients with neurosyphilis.Methods: Four HIV-negative neurosyphilis patients and 4 healthy controls underwent clinical evaluation, brain technetium-99m ethyl cysteinate dimer (99mTc-ECD) single-photon emission computed tomography (SPECT) imaging, and neuropsychological assessments which included the Mini-Mental State Examination (MMSE), Clinical Dementia Rating (CDR), Clinical Dementia Rating—Sum of Boxes (CDR-SOB), and Global Deterioration Scale (GDS). Voxel-wise differences in regional cerebral blood flow were compared between the two groups.Results: Neuropsychological test results indicated cognitive impairment in all patients. SPECT analysis revealed multifocal hypoperfusion predominantly in the frontal, insular, and posterior cingulate regions in neurosyphilis patients compared with healthy controls (family-wise error corrected p < 0.05).Conclusions: Together with previous findings, our results suggest that the hypoperfusion in the frontal, insular, and posterior cingulate regions may reflect cognitive impairments observed in neurosyphilis patients. Further studies with larger samples are needed to confirm our findings.

Modeling Cerebral Blood Flow and Ventilation Instability due to CO2

2021 ◽  
Author(s):  
Stanley M. Yamashiro ◽  
Takahide Kato
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Current Model ◽  
Respiratory Control ◽  
Breath Hold ◽  
Chronic Obstructive ◽  
Brain Blood Flow ◽  
Linear Interaction ◽  
Non Linear ◽  
Flow Changes

A minimal model of cerebral blood flow and respiratory control was developed to describe hypocapnic and hypercapnic responses. Important non-linear properties such as cerebral blood flow changes with arterial partial pressure of carbon dioxide (PaCO2) and associated time dependent circulatory time delays were included. It was also necessary to vary cerebral metabolic rate as a function of PaCO2. The cerebral blood flow model was added to a previously developed respiratory control model to simulate central and peripheral controller dynamics for humans. Model validation was based on previously collected data. The variable time delay due to brain blood flow changes in hypercapnia was an important determinant of predicted instability due to non-linear interaction in addition to linear loop gain considerations. Peripheral chemoreceptor gains above a critical level, but within normal limits, was necessary to produce instability. Instability was observed in recovery from hypercapnia and hypocapnia. The 20 sec breath-hold test appears to be a simple test of brain blood flow mediated instability in hypercapnia. Brain blood flow was predicted to play an important role with non-linear properties. There is an important interaction predicted by the current model between central and peripheral control mechanisms related to instability in hypercapnia recovery. Post hyperventilation breathing pattern can also reveal instability tied to brain blood flow. Previous data collected in patients with chronic obstructive lung disease was closely fitted with the current model and instability predicted. Brain vascular volume was proposed as a potential cause of instability despite cerebral autoregulation promoting constant brain flow.

scholarly journals Analisis Dimensi Fraktal Kejadian Gempa Dl Laut Banda Indonesia

2016 ◽  
Vol 19 (2) ◽  
pp. 108
Author(s):  
Sugeng Widada
Keyword(s):  
Fractal Dimension ◽  
Fractal Analysis ◽  
Fractal Approach ◽  
Study Support ◽  
Tectonic System

The Banda Sea region is an active earthquakes area which indicated by mean monthly incident of quakes more than 220. The condition is caused the area being located in the triple jucntion. Earthquakes system in this region which occur during September 2015 up to October 2016 is analyzed by fractal approach to investigate the subduction system.Earthquakes system is chaotic, so can be quantified using fractal concept. Quantify result of Banda Sea earthquakes system using Aki method is fractal dimension 2.08. It indicates that the slab was fractured by some fault in form an angle or upright possition with the subduction strike. Such a thing also be proven by the fact that the length zone of slab moved during each earthquake is not same, the variation is about 6 – 1,056 m. Based on the fractal analysis, also be identified that about 6.25 magnitute six earthquakes are expected each year. The result of study support the previous studies which propose that the tectonic system in Banda Sea region is very complex. Keywards:  Earthuakes system, fractal, Banda Sea Kawasan Laut Banda merupakan daerah aktif gempa yang ditunjukan dengan kejadian gempa rata-rata bulanan Iebih dan 220. Keadaan ini dapat dimengerti mengingat kawasan tersebut merupakan pertemuan tiga buah lempeng yang bergerak. Pola kegempaan di daerah tesebut yang tejadi pada September 2015 hingga Oktober 2016 dicoba dianalisa menggunakan pendekatan fraktal untuk mengetahui pola subduksi di daerah tersebut. Pola kegempaan merupakan suatu kejadian yang chaos, sehingga dapat dilakukan kuantisasi berdasarkan konsep fraktal. Hasil kuantisasi pola gempa Laut Banda meggunakan metode Aki diperoleh dimensi fraktal 2,08. Hal ini menunjukan bahwa slab yang menunjam dan bergerak sehingga menimbulkan gempa terbagi dalarn beberapa bagian melalui suatu sesar yang menyududut / tegak lurus jurus subduksi. Keadaan ini dikuatkan oleh hasil perhitungan panjang daerah yang bergerak untuk setiap kejadian gempa tidak sama, yaitu bervariasi dari 6 – 1.056 m. Berdasarkan analisa fraktal tersebut juga diketahui bahwa gempa dengan magnitudo 6,25 akan terjadi 6 kali dalam satu tahun. Hasil penelitian ini mendukung hasil penelitian terdahulu yang menyatakan bahwa tatanan tektonik di daerah Laut Banda sangat kompleks. Kata Kunci: Pole gempa, fraktal, Laut Banda

A-67 Measuring Regional Cerebral Blood Flow with Single-Photon Emission Computed Tomography (SPECT) in Obsessive–Compulsive Disorder

2021 ◽  
Vol 36 (6) ◽  
pp. 1109-1109
Author(s):  
Sophia G Perez ◽  
Bailey McDonald ◽  
Samantha Spagna ◽  
Charles J Golden ◽  
Kristen Willeumier ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Basal Ganglia ◽  
Limbic System ◽  
Regional Cerebral Blood Flow ◽  
Healthy Controls ◽  
Regional Cerebral Blood ◽  
Obsessive Compulsive ◽  
Compulsive Disorder ◽  
The Right

Abstract Objective To identify regional cerebral blood flow (rCBF) differences between individuals with Obsessive–Compulsive Disorder (OCD) and healthy controls. Mehtods: Healthy controls (n = 81, Mage = 41.9, 53.0% female, 42.0% Caucasian) and persons diagnosed by psychiatric examination with OCD (n = 1020, Mage = 34.8, 33.6% female, 66.3% Caucasian) were selected from a deidentified adult clinical outpatient database. Those with comorbid diagnoses were included. Significant differences (alpha = 0.001) were found for age [t(1099) = −4.4], gender [χ2(2) = 25.7], and race [χ2(12) = 30.1] between groups and therefore were controlled for. Significant rCBF differences were noted in the cerebellum [left:F(1,1096) = 21.6; right:F(1,1096) = 18.3], limbic system [left:F(1,1096) = 12.2; right:F(1,1096) = 10.4], and basal ganglia [left:F(1,1096) = 18.6; right:F(1,1096) = 18.3]. Results Group means comparisons indicated higher perfusion in the cerebellum for the OCD group. Lower perfusion was found in the limbic system and basal ganglia in the OCD group. This study found higher perfusion in the cerebellum among the OCD group. Previous research found increased rCBF in the left cerebellum in OCD before pharmacotherapy. In the right cerebellum, increased rCBF was found among participants with early-onset OCD. Conclusion Overall, there is limited research on the cerebellum because of its use as a reference point. No research was found regarding the limbic system in OCD using SPECT; however, other neuroimaging found increased amygdala reactivity to emotional face stimuli. This study found lower perfusion in the basal ganglia among the OCD group. Previous research found hypoperfusion in the right; however, hypoperfusion in the left was not significant. Updated OCD and rCBF research with SPECT are needed. Limitations included the inclusion of comorbidities and use of DSM-IV-TR rather than DSM-5 diagnosis criteria.

Validity of Doppler Measurements of Anterior Cerebral Artery Blood Flow Velocity: Correlation with Brain Blood Flow in Piglets

PEDIATRICS ◽  
1983 ◽  
Vol 72 (4) ◽  
pp. 526-531
Author(s):  
Nancy B. Hansen ◽  
Barbara S. Stonestreet ◽  
Ted S. Rosenkrantz ◽  
William Oh
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Flow Velocity ◽  
Blood Flow Velocity ◽  
Continuous Wave ◽  
Anterior Cerebral Artery ◽  
Brain Blood Flow ◽  
Velocity Measurements ◽  
Doppler Flow ◽  
Continuous Wave Doppler

Continuous wave Doppler ultrasonography through the anterior fontanel has recently been used to assess changes in cerebral blood flow in human neonates. There has been controversy concerning whether measurements of Doppler blood flow velocity indeed correlate with brain blood flow. An in vivo correlation was performed between brain blood flow as measured by the microsphere method and Doppler flow velocity measurements of the cerebral arteries via an artificial fontanel in young piglets. The peak systolic velocity (r = .76, P < .001), end diastolic velocity (r = .72, P < .001) and area under the velocity curve (r = .86, P<.001) all showed significant positive correlations with brain blood flow. The pulsatility index did not correlate with brain blood flow. Although continuous wave Doppler flow velocity measurements of the anterior cerebral artery cannot quantitatively assess cerebral blood flow, this methodology can be used to correlate changes in cerebral blood flow and provide a meaningful trend analysis following physiologic or pharmacologic perturbation of the cerebral circulation.

Reduced regional cerebral blood flow measured by 99mTc-HMPAO SPECT in microgravity simulated by 5-day dry immersion

2021 ◽  
Author(s):  
Laurent Guillon ◽  
Marc Kermorgant ◽  
Thomas Charvolin ◽  
Fabrice Bonneville ◽  
Marie-Pierre Bareille ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Regional Cerebral Blood Flow ◽  
Peak Level ◽  
Emission Computed Tomography ◽  
Regional Cerebral Blood ◽  
Caudate Nuclei ◽  
Dry Immersion ◽  
Hmpao Spect ◽  
Significant Difference

Abstract Purpose Neuro-ophthalmological changes defined as spaceflight-associated neuro-ocular syndrome have been reported after long duration space flights. The pathophysiology of this syndrome remains unclear, with the possible involvement of elevated intracranial pressure. Changes in blood flow in the brain, evaluated indirectly by Doppler, have been reported in flight. However, the effects of microgravity on regional cerebral blood flow (rCBF) are not known. We therefore investigated changes in rCBF in a 5-day dry immersion (DI) model. Moreover, we tested thigh cuffs as a countermeasure to prevent potential microgravity-induced modifications in rCBF.Methods 18 healthy male participants underwent 5-day DI with or without a thigh cuffs countermeasure. They were randomly allocated to a control (n = 9) or cuffs (n = 9) group. rCBF was measured 4 days before DI (Pre-DI) and at the end of the fifth day of DI (Post-DI), using single-photon emission computed tomography (SPECT) with radiopharmaceutical 99mTc-hexamethyl propylene amine oxime (HMPAO). SPECT images were processed using statistical parametric mapping (SPM12) software.Results At DI5, we observed a significant decrease in rCBF in 32 cortical and subcortical patterns, with greater hypoperfusion in the occipital region (occipital peak level: z = 4.51, puncorr < 0.001) and basal ganglia (putamen peak level: z = 4.71, puncorr < 0.001; caudate nuclei peak level: z = 3.80, puncorr < 0.001). No significant difference was found between the control and cuffs groups on variations in rCBF at DI5.Conclusion 5-day DI induces a relative decrease in rCBF in cortical and subcortical regions. Nevertheless, the consequences of this decrease for brain function and mechanisms need further investigation.

Regional cerebral blood flow response during and after acute asphyxia in newborn piglets

1989 ◽  
Vol 66 (6) ◽  
pp. 2827-2832 ◽  
Author(s):  
J. M. Goplerud ◽  
L. C. Wagerle ◽  
M. Delivoria-Papadopoulos
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Brain Stem ◽  
Regional Cerebral Blood Flow ◽  
Muscle Blood Flow ◽  
Organ Blood Flow ◽  
Brain Blood Flow ◽  
Regional Cerebral Blood ◽  
Newborn Piglets ◽  
Total Brain

The hemodynamic response during and after acute asphyxia was studied in 14 newborn piglets. An apnea-like asphyxial insult was produced in paralyzed mechanically ventilated piglets by discontinuing ventilation until the piglets became bradycardic (heart rate less than 80 beats/min). Seven piglets had organ blood flow measured by microspheres at control, during asphyxia (PO2 = 16 +/- 11 Torr, pH = 7.31 +/- 0.07, PCO2 = 47 +/- 9 Torr), and during recovery from asphyxia. During acute asphyxia, rapid organ blood flow redistribution occurred, producing decreased renal and skeletal muscle blood flow, while coronary blood flow increased. Although total brain blood flow changed little during asphyxia, regional cerebral blood flow (rCBF) analysis revealed significant nonhomogeneous blood flow distribution within the brain during asphyxia, with decreases to the cerebral gray and white matter and the choroid plexus, whereas brain stem structures had increased flow. During recovery with reventilation, total brain blood flow increased 24% above control, with a more uniform distribution and increased flow to all brain regions. The time course of rCBF changes during acute asphyxia was then determined in seven additional piglets with CBF measurements made sequentially at 30–60 s, 60–120 s, and 120–180 s of asphyxia. The vasoconstriction seen in cortical structures, concurrent with the reduction in skeletal and kidney blood flow, known to be sympathetically mediated, suggest a selective reflex effect in this brain region. The more gradual and progressive vasodilation in brain stem regions during asphyxia is consistent with chemical control. These findings demonstrate significant regional heterogeneity in CBF regulation in newborn piglets.

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