scholarly journals Development of an H215O Steady-State Method Combining a Bolus and Slow Increasing Injection with a Multiprogramming Syringe Pump

2010 ◽  
Vol 31 (2) ◽  
pp. 527-534 ◽  
Author(s):  
Masato Kobayashi ◽  
Yasushi Kiyono ◽  
Rikiya Maruyama ◽  
Tetsuya Mori ◽  
Keiichi Kawai ◽  
...  
Keyword(s):  
Steady State ◽  
Animal Studies ◽  
Quantitative Measurement ◽  
Small Animal ◽  
Syringe Pump ◽  
Arterial Blood ◽  
Steady State Method ◽  
Positron Emission ◽  
State Method ◽  
Pet Scans

An 15O-labeled water (H215O) steady-state method for quantitative measurement of cerebral blood flow ( CBF), which is less stressful to small animals with a few point blood sampling, was developed. After a simulation using a dose meter to achieve stable H215O radioactivity in the blood with a multiprogramming syringe pump programmed for slowly increasing injection volume, 10 rats were studied with the injection method. Arterial blood was sampled every minute during 6-minute positron emission tomography (PET) scans. After the PET scan, N-isopropyl- p-[125I]-iodoamphetamine (125I-IMP) was injected into the same rat to measure CBF using the autoradiography method based on a microsphere model. Regions of interest were placed on the whole brain in H215O-PET and 125I-IMP-autoradiography images, and CBF values calculated from both methods were compared. Radioactivity in the dose meter achieved equilibrium ~1 minute after starting the H215O injection. In rat studies, radioactivity in the blood and brain rapidly achieved equilibrium at 2 minutes after administration. The correlation of CBF values of H215O PET (49.2 ± 5.4 mL per 100 g per minute) and those of 125I-IMP autoradiography (49.1 ± 5.2 mL per 100 g per minute) was excellent ( y = 1.01 x −0.37, r2 = 0.97). The H215O steady-state method with a continuously increasing injection is useful for CBF measurement in small animal studies, especially when multiple scans are required in the same animal.

scholarly journals Linearization Correction of 99mTc-Labeled Hexamethyl-Propylene Amine Oxime (HM-PAO) Image in Terms of Regional CBF Distribution: Comparison to C15O2 Inhalation Steady-State Method Measured by Positron Emission Tomography

1988 ◽  
Vol 8 (1_suppl) ◽  
pp. S52-S60 ◽  
Author(s):  
Atsushi Inugami ◽  
Iwao Kanno ◽  
Kazuo Uemura ◽  
Fumio Shishido ◽  
Matsutaro Murakami ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Steady State ◽  
Emission Tomography ◽  
Emission Computed Tomography ◽  
Whole Brain ◽  
Steady State Method ◽  
Positron Emission ◽  
State Method

The radioisotope distribution following intravenous injection of 99mTc-labeled hexamethylpropyleneamine oxime (HM-PAO) in the brain was measured by single photon emission computed tomography (SPECT) and corrected for the nonlinearity caused by differences in net extraction. The “linearization” correction was based on a three compartment model, and it required a region of reference to normalize the SPECT image in terms of regional cerebral blood flow distribution. Two different regions of reference, the cerebellum and the whole brain, were tested. The uncorrected and corrected HM-PAO images were compared with cerebral blood flow (CBF) image measured by the C15O2 inhalation steady state method and positron emission tomography (PET). The relationship between uncorrected HM-PAO and PET–CBF showed a correlation coefficient of 0.85 but tended to saturate at high CBF values, whereas it was improved to 0.93 after the “linearization” correction. The whole-brain normalization worked just as well as normalization using the cerebellum. This study constitutes a validation of the “linearization” correction and it suggests that after linearization the HM-PAO image may be scaled to absolute CBF by employing a global hemispheric CBF value as measured by the nontomographic 133Xe clearance method.

scholarly journals Quantitative Comparison of the Bolus and Steady-State Methods for Measurement of Cerebral Perfusion and Oxygen Metabolism: Positron Emission Tomography Study Using 15O-Gas and Water

2001 ◽  
Vol 21 (7) ◽  
pp. 793-803 ◽  
Author(s):  
Hidehiko Okazawa ◽  
Hiroshi Yamauchi ◽  
Kanji Sugimoto ◽  
Masaaki Takahashi ◽  
Hiroshi Toyoda ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Steady State ◽  
Blood Volume ◽  
Cerebral Perfusion ◽  
Oxygen Metabolism ◽  
Emission Tomography ◽  
Parametric Images ◽  
Steady State Method ◽  
Positron Emission ◽  
State Method

To evaluate a new simplified bolus method for measurement of cerebral perfusion and metabolism, the parametric images with that method were compared with those obtained from the conventional steady-state method with 15O-gas. The new method also provided images of arterial blood volume (V0), which is a different parameter from cerebral blood volume (CBV) obtained using a C15O technique. Seven healthy volunteers and 10 patients with occlusive cerebrovascular diseases underwent positron emission tomography (PET) scans with both methods. Three-weighted integration was applied to calculate regional cerebral blood flow (rCBF) and regional cerebral metabolic rate of oxygen (rCMRO2) in the bolus method. Global and regional CBF and CMRO2 in volunteers were compared between the two methods and used as control data. Regional values in patients also were evaluated to observe differences between the bilateral hemispheres. Both rCBF and rCMRO2 were linearly well correlated between the two methods, although global difference in CMRO2 was significant. The difference in each parametric image except for V0 was significant between the bilateral hemispheres in patients. The bolus method can simplify oxygen metabolism studies and yield parametric images comparable with those with the steady-state method, and can allow for evaluation of V0 simultaneously. Increase in CBV without a change in V0 suggested the increase might mainly be caused by venous dilatation in the ischemic regions.

scholarly journals The 15O Steady-State Method: Correction for Variation in Arterial Concentration

1988 ◽  
Vol 8 (5) ◽  
pp. 681-690 ◽  
Author(s):  
Michio Senda ◽  
Richard B. Buxton ◽  
Nathaniel M. Alpert ◽  
John A. Correia ◽  
Bruce C. Mackay ◽  
...  
Keyword(s):  
Steady State ◽  
Statistical Error ◽  
Repeated Measurements ◽  
New Method ◽  
Oxygen Extraction Fraction ◽  
Inhalation Technique ◽  
Arterial Blood ◽  
Steady State Method ◽  
Arterial Concentration ◽  
State Method

One of the factors limiting the accuracy of the 15O steady-state method for the measurement of regional cerebral blood flow and oxygen metabolism is the requirement that a constant arterial blood concentration be maintained over long periods. A new method has been developed to correct for the variation of the arterial concentration in the C15O2 and 15O2 steady-state inhalation technique. The time course of the arterial activity is obtained by multiple sampling over the study period. The same 15O model as is used in the steady-state method is employed but is solved without assuming equilibrium. Look-up tables are generated to relate flow and oxygen extraction fraction to tissue activity, and from them the regional parameters are estimated. Theory and simulation studies suggest that substantial improvement in accuracy can be obtained with no increase in statistical error. The validity of the method was checked experimentally by making repeated measurements in the same subject after perturbing the gas delivery. The conventional steady-state method showed significantly larger deviations in repeat measurement than did the new method. Thus, it is concluded that the proposed method is superior.

scholarly journals Cerebral Oxygen Metabolism of Rats using Injectable 15O-Oxygen with a Steady-State Method

2011 ◽  
Vol 32 (1) ◽  
pp. 33-40 ◽  
Author(s):  
Masato Kobayashi ◽  
Tetsuya Mori ◽  
Yasushi Kiyono ◽  
Vijay Narayan Tiwari ◽  
Rikiya Maruyama ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Steady State ◽  
Emission Tomography ◽  
Tracer Injection ◽  
Simple Method ◽  
Whole Brain ◽  
Steady State Method ◽  
Positron Emission ◽  
State Method ◽  
Cerebral Arterial Occlusion

To develop a less-stressful and simple method for measurement of the cerebral metabolic rate of oxygen ( CMRO2) in small animals, the steady-state method was applied to injectable 15O2-PET (15O2-positron emission tomography) using hemoglobin-containing vesicles (15O2-HbV). Ten normal rats and 10 with middle cerebral arterial occlusion (MCAO) were studied using a small animal PET scanner. A series of 15O-PET scans with C15O-labeled HbV, H215O, and 15O2-HbV were performed with 10 to 15 minutes intervals to measure cerebral blood volume (CBV), cerebral blood flow (CBF), and CMRO2. Positron emission tomography scans were started with a tracer injection using a multiprogramming syringe pump, which provides a slowly increasing injection volume to achieve steady-state radioactivity for H215O and 15O2-HbV scans. The radioactivity concentration of 15O rapidly achieved equilibrium in the blood and whole brain at about 2 minutes after H215O and 15O2-HbV administration, which was stable during the scans. The whole brain mean values of CBF, CBV, and CMRO2 were 54.3 ± 2.0 mL per 100 g per minute, 4.9 ± 0.4 mL/100 g, and 2.8 ±0.2 μmoL per g per minute (6.2 ± 0.4 mL per 100 g per minute) in the normal rats, respectively. In the MCAO model rats, all hemodynamic parameters of the infarction area on the occlusion side significantly decreased. The steady-state method with 15O-labeled HbV is simple and useful to analyze hemodynamic changes in studies with model animals.

Influence of indomethacin on ventilatory and cerebrovascular responsiveness to CO2 and breathing stability: the influence of Pco2 gradients

2010 ◽  
Vol 298 (6) ◽  
pp. R1648-R1658 ◽  
Author(s):  
Jui-Lin Fan ◽  
Keith R. Burgess ◽  
Kate N. Thomas ◽  
Karen C. Peebles ◽  
Samuel J. E. Lucas ◽  
...  
Keyword(s):  
Steady State ◽  
Blood Gases ◽  
Cerebrovascular Reactivity ◽  
Arterial Blood Gases ◽  
Ventilatory Control ◽  
Arterial Blood ◽  
Steady State Method ◽  
Variability Index ◽  
State Method

Indomethacin (INDO), a reversible cyclooxygenase inhibitor, is a useful tool for assessing the role of cerebrovascular reactivity on ventilatory control. Despite this, the effect of INDO on breathing stability during wakefulness has yet to be examined. Although the effect of reductions in cerebrovascular CO2 reactivity on ventilatory CO2 sensitivity is likely dependent upon the method used, no studies have compared the effect of INDO on steady-state and modified rebreathing estimates of ventilatory CO2 sensitivity. The latter method includes the influence of Pco2 gradients and cerebral perfusion, whereas the former does not. We examined the hypothesis that INDO-induced reduction in cerebrovascular CO2 reactivity would 1) cause unstable breathing in conscious humans and 2) increase ventilatory CO2 sensitivity during the steady-state method but not during rebreathing methods. We measured arterial blood gases, ventilation (V̇e), and middle cerebral artery velocity (MCAv) before and 90 min following INDO ingestion (100 mg) or placebo in 12 healthy participants. There were no changes in resting arterial blood gases or V̇e following either intervention. INDO increased the magnitude of V̇e variability (index of breathing stability) during spontaneous air breathing (+4.3 ± 5.2 Δl/min, P = 0.01) and reduced MCAv (−25 ± 19%, P < 0.01) and MCAv-CO2 reactivity during steady-state (−47 ± 27%, P < 0.01) and rebreathing (−32 ± 25%, P < 0.01). The V̇e-CO2 sensitivity during the steady-state method was increased with INDO (+0.5 ± 0.5 l·min−1·mmHg−1, P < 0.01), while no changes were observed during rebreathing ( P > 0.05). These data indicate that the net effect of INDO on ventilatory control is an enhanced ventilatory loop gain resulting in increased breathing instability. Our findings also highlight important methodological and physiological considerations when assessing the effect of INDO on ventilatory CO2 sensitivity, whereby the effect of INDO-induced reduction of cerebrovascular CO2 reactivity on ventilatory CO2 sensitivity is unmasked with the rebreathing method.

Steady State Measurement of Oxygenation Capacity

1985 ◽  
Vol 17 (2-3) ◽  
pp. 303-311
Author(s):  
Kees de Korte ◽  
Peter Smits
Keyword(s):  
Steady State ◽  
Activated Sludge ◽  
Plug Flow ◽  
Usual Method ◽  
Steady State Method ◽  
State Measurement ◽  
Flow Systems ◽  
Air System ◽  
State Method ◽  
Steady State Measurement

The usual method for OC measurement is the non-steady state method (reaeration) in tapwater or, sometimes, in activated sludge. Both methods are more or less difficult and expensive. The steady state method with activated sludge is presented. Fundamentals are discussed. For complete mixed aeration tanks, plug flow systems with diffused air aeration and carousels the method is described more in detail and the results of measurements are presented. The results of the steady state measurements of the diffused air system are compared with those of the reaeration method in tapwater. The accuracy of the measurements in the 3 systems is discussed. Measurements in other aeration systems are described briefly. It is concluded that the steady state OC measurement offers advantages in comparison with the non-steady state method and is useful for most purposes.

Sign in / Sign up

Export Citation Format

Share Document