Effect of arterial CO 2 tension on cerebral blood flow, mean transit time, and vascular volume.

1971 ◽  
Vol 31 (5) ◽  
pp. 701-707 ◽  
Author(s):  
A L Smith ◽  
G R Neufeld ◽  
A J Ominsky ◽  
H Wollman
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Transit Time ◽  
Mean Transit Time ◽  
Vascular Volume

scholarly journals Interrelationships Among Regional Cerebral Blood Flow, Mean Transit Time, Vascular Volume and Cerebral Vascular Resistance

Stroke ◽  
1974 ◽  
Vol 5 (6) ◽  
pp. 719-724 ◽  
Author(s):  
YOSHIHIRO KURIYAMA ◽  
TAKASHI AOYAMA ◽  
KUNIHIKO TADA ◽  
SHOTARO YONEDA ◽  
TADAATSU NUKADA ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Vascular Resistance ◽  
Transit Time ◽  
Regional Cerebral Blood Flow ◽  
Mean Transit Time ◽  
Regional Cerebral Blood ◽  
Vascular Volume ◽  
Cerebral Vascular Resistance ◽  
Cerebral Vascular

Effects of graded hypotension on cerebral blood flow, blood volume, and mean transit time in dogs

1992 ◽  
Vol 262 (6) ◽  
pp. H1908-H1914 ◽  
Author(s):  
M. Ferrari ◽  
D. A. Wilson ◽  
D. F. Hanley ◽  
R. J. Traystman
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Cerebral Perfusion Pressure ◽  
Blood Volume ◽  
Transit Time ◽  
Cerebral Perfusion ◽  
Pressure Range ◽  
Cerebral Blood Volume ◽  
Perfusion Pressure ◽  
Mean Transit Time

This study tested the hypothesis that cerebral blood flow (CBF) is maintained by vasodilation, which manifests itself as a progressive increase in mean transit time (MTT) and cerebral blood volume (CBV) when cerebral perfusion pressure is reduced. Cerebral perfusion pressure was decreased in 10 pentobarbital-anesthetized dogs by controlled hemorrhage. Microsphere-determined CBF was autoregulated in all tested cerebral regions over the 40- to 130-mmHg cerebral perfusion pressure range but decreased by 50% at approximately 30 mmHg. MTT and CBV progressively and proportionately increased in the right parietal cerebral cortex over the 40- to 130-mmHg cerebral perfusion pressure range. Total hemoglobin content (Hb1), measured in the same area by an optical method, increased in parallel with the increases in CBV computed as the (CBF.MTT) product. At 30 mmHg cerebral perfusion pressure, CBV and Hb were still increased and MTT was disproportionately lengthened (690% of control). We conclude that within the autoregulatory range, CBF constancy is maintained by both increased CBV and MTT. Outside the autoregulatory range, substantial prolongation of the MTT occurs. When CBV is maximal, further reductions in cerebral perfusion pressure produce disproportionate increases in MTT that signal the loss of cerebral vascular dilatory hemodynamic reserve.

CEREBRAL BLOOD FLOW/VOLUME/MEAN TRANSIT TIME RELATIONSHIPS IN THE DOG DURING HEMORRHAGIC HYPOTENSION

1987 ◽  
Vol 15 (4) ◽  
pp. 432
Author(s):  
David A. Wilson ◽  
Marco Ferrari ◽  
Daniel F. Hanley ◽  
Mark C. Rogers ◽  
Richard J. Traystman
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Transit Time ◽  
Mean Transit Time ◽  
Flow Volume ◽  
Hemorrhagic Hypotension ◽  
Blood Flow Volume

Comparison of Renal Blood Flow and Transit Times Measured by Means of 99mTc-Labelled Erythrocytes and Indocyanine Green in Humans with Normal and Diseased Kidneys

1976 ◽  
Vol 51 (2) ◽  
pp. 151-159
Author(s):  
F. C. Reubi ◽  
C. Vorburger ◽  
Gertrud Pfeiffer ◽  
S. Golder
Keyword(s):  
Blood Flow ◽  
Indocyanine Green ◽  
Renal Blood Flow ◽  
Transit Time ◽  
Mean Transit Time ◽  
Common Mechanism ◽  
Dilution Method ◽  
Appearance Time ◽  
Vascular Volume ◽  
Transit Times

1. In nineteen patients with normal or diseased kidneys, renal blood flow, transit times and vascular volume were determined by means of an indicator-dilution method. Two different indicators, plasma-bound Indocyanine Green (IG) and 99mTc-labelled erythrocytes, were used simultaneously. 2. Comparison of the results indicates that IG slightly overestimates renal blood flow, appearance time, mean transit time and vascular volume, as the erythrocyte/IG ratios averaged 0·972, 0·903, 0·93 and 0·921 respectively. Overestimation of the mean transit time was less apparent when it was prolonged. In patients with reduced renal function, the average blood flow values obtained with the two indicators were in good agreement. 3. It is unlikely that axial streaming of erythrocytes accounts for their shorter mean transit time, because the individual erythrocyte/IG mean transit time ratios were independent of the rate of blood flow and the peripheral packed cell volume. 4. Since the erythrocyte/IG mean transit time ratios correlated significantly with the erythrocyte/IG ratios for appearance time and renal blood flow, the common mechanism leading to a depression of all erythrocyte/IG ratios is presumably extravascular circulation and delayed recovery of a small fraction of IG.

The effect of increased intracranial pressure on cerebrovascular hemodynamics

1971 ◽  
Vol 34 (6) ◽  
pp. 760-769 ◽  
Author(s):  
Harry M. Lowell ◽  
Byron M. Bloor
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Intracranial Pressure ◽  
Transit Time ◽  
Mean Transit Time ◽  
Progressive Decrease ◽  
Increased Intracranial Pressure ◽  
Sagittal Sinus ◽  
The Mean ◽  
Wedge Pressure

✓ Both brain edema (increased water content) and enlargement of the vascular compartment have been implicated as being responsible for intracranial hypertension following trauma. In this study pertinent cerebrovascular hemodynamic parameters have been investigated in states of increased intracranial pressure (ICP) and graded trauma to determine whether cerebral edema or vascular factors are of major importance. Utilizing the monkey-epidural balloon experimental model, continuous measurements of the mean arterial pressure (MABP) , jugular outflow pressure (MJVP), and sagittal sinus wedge pressure (SSWP) were obtained. Shulman's observations that the sagittal sinus wedge pressure accurately reflects the intracranial pressure have been confirmed. The total cerebral blood flow (CBF) and mean transit time (t̄) were determined and the total cerebral blood volume (CBV) computed. From these data the venous (Rv), arterial (Ra), and total resistances (Rt) were calculated. Analysis of these parameters during both the acute elevation of ICP and that following graded trauma has demonstrated: 1) a progressive decrease in the total cerebral blood flow and volume and a concomitant increase in the mean transit time; 2) a progressive increase in the total resistance with a shift from the arterial to the venous side; 3) a progressive decrease in the perfusion pressure (PP = MABP-SSWP); 4) impairment of CO2 reactivity pari passu with vasomotor activity and autoregulation of flow to pressure. The findings did not support the concept that increased intracranial pressure following trauma is the result of an increase in the size of the cerebrovascular compartment.

Arterial spin labeling in patients with chronic cerebral artery steno-occlusive disease: Correlation with 15O-PET

2013 ◽  
Vol 54 (1) ◽  
pp. 99-106 ◽  
Author(s):  
Hironori Kamano ◽  
Takashi Yoshiura ◽  
Akio Hiwatashi ◽  
Koichiro Abe ◽  
Osamu Togao ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Transit Time ◽  
Cerebral Artery ◽  
Regional Cerebral Blood Flow ◽  
Flow Measurement ◽  
Mean Transit Time ◽  
Regional Cerebral Blood ◽  
Cerebral Blood Flow Measurement ◽  
Arterial Transit Time

Background Heterogeneity of arterial transit time due to cerebral artery steno-occlusive lesions hampers accurate regional cerebral blood flow measurement by arterial spin labeling (ASL). Purpose To assess the feasibility of regional cerebral blood flow measurement by ASL with multiple-delay time sampling in patients with steno-occlusive diseases by comparing with positron emission tomography (PET), and to determine whether regional arterial transit time measured by this ASL technique is correlated with regional mean transit time, a PET index of perfusion pressure. Material and Methods Sixteen patients with steno-occlusive diseases received both ASL and 15O-PET. The mean regional cerebral blood flow measured by ASL and PET, regional arterial transit time by ASL, and regional mean transit time by PET were obtained by a region-of-interest analysis. Correlation between regional cerebral blood flow by ASL and that by PET, and correlation between regional arterial transit time by ASL and regional mean transit time by PET were tested using Pearson's correlation coefficient for both absolute and relative values. A multivariate regression analysis was performed to test whether regional arterial transit time by ASL was a significant contributor in modeling regional mean transit time by PET after controlling the effect of regional cerebral blood flow by ASL. Results A significant positive correlation was found between regional cerebral blood flow by ASL and that by PET for both absolute (r = 0.520, P < 0.0001) and relative (r = 0.691, P < 0.0001) values. A significant positive correlation was found between regional arterial transit time by ASL and regional mean transit time by PET both for absolute (r = 0.369, P = 0.0002) and relative (r = 0.443, P < 0.0001) values. The regression analysis revealed that regional arterial transit time by ASL was a significant contributor in modeling regional mean transit time by PET after controlling regional cerebral blood flow by ASL (P = 0.0011). Conclusion The feasibility of regional cerebral blood flow measurement using ASL with multiple-delay time sampling was confirmed in patients with cerebral artery steno-occlusive diseases. Moreover, it was suggested that mapping of regional arterial transit time has the potential to detect hemodynamic impairment.

scholarly journals Cerebral Blood Flow, Blood Volume, and Mean Transit Time Responses to Propofol and Indomethacin in Peritumor and Contralateral Brain Regions

2010 ◽  
Vol 112 (1) ◽  
pp. 50-56 ◽  
Author(s):  
Mads Rasmussen ◽  
Niels Juul ◽  
Søren M. Christensen ◽  
Kristjana Y. Jónsdóttir ◽  
Carsten Gyldensted ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Brain Tumors ◽  
Blood Volume ◽  
Transit Time ◽  
Gray Matter ◽  
Cerebral Blood Volume ◽  
Mean Transit Time ◽  
Brain Regions ◽  
Normal Brain

Background The regional cerebral blood flow (CBF) response to propofol and indomethacin may be abnormal in patients with brain tumors. First, the authors tested the hypothesis that during propofol anesthesia alone and combined with indomethacin, changes in CBF, cerebral blood volume (CBV), and plasma mean transit time (MTT) differ in the peritumoral tissue compared with the contralateral normal brain region. Second, the authors tested the hypothesis that CBF and CBV are reduced and MTT is prolonged, in both regions during propofol anesthesia and indomethacin administration compared with propofol alone. Methods The authors studied eight patients subjected to craniotomy under propofol-fentanyl anesthesia for supratentorial brain tumors. Magnetic resonance imaging, including perfusion- and diffusion-weighted and structural sequences, was performed (1) on the day before surgery, (2) before and (3) after administration of indomethacin in the propofol-fentanyl anesthetized patient, and (4) 2 days after surgery. Maps of CBF, CBV, and MTT were calculated. The regions of interest were peritumoral gray matter and opposite contralateral gray matter. Analysis of variance was used to analyze flow data. Results Propofol anesthesia was associated with a median 32% (range, 3-61%) and 47% (range, 17-67%) reduction in CBF in the peritumoral and contralateral regions, respectively.The interaction between intervention with propofol and indomethacin and region of interest was not significant for any flow modalities. Neither intervention nor region was significant for MTT, CBF, and CBV (P &gt; 0.05). Conclusion The CBF, CBV, and MTT responses to propofol and indomethacin are not different in the peritumoral region compared with contralateral brain tissue. Indomethacin did not further influence regional CBF, CBV, and MTT during propofol anesthesia.

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