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K. M A Welch - One of the best experts on this subject based on the ideXlab platform.
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Cerebral Blood Flow in chronic posttraumatic headache
Headache, 1997Co-Authors: Stephanie J. Gilkey, Nabih M. Ramadan, Taruna K. Aurora, K. M A WelchAbstract:Background and Purpose.-Headache is the most common neurologic symptom following minor closed head injury. There is often a lack of objective evidence supporting an organic basis of Cerebral pathology in these cases. This pilot study considers the possibility of alterations in Cerebral Blood Flow, indicating evidence of an organic disorder in posttraumatic headache. Methods.-Regional Cerebral Blood Flow studies of 35 patients with chronic posttraumatic headache (PTH) (International Headache Society criteria), identified retrospectively from our Cerebral Blood Flow data base, were compared with those of 49 nonheadache controls and 92 migraineurs (Ad Hoc Committee criteria). Regional Cerebral Blood Flow (initial slope index method) was measured using the xenon Xe 133 inhalation technique. Results.-Compared to migraineurs and controls, and after adjusting for differences (analysis of covariance) in baseline variables such as Blood pressure, hematocrit, and Pco 2 , patients with PTH had: (1) significantly lower mean initial slope indices (P<0.001, P=0.002, respectively); (2) regional interhemispheric Flow differences (rlFD), with higher distribution of regional asymmetrical probe pairs (rIFD≥7%: P[PTH versus control]=0.006, P[PTH versus migraine]=0.016; rIFD≥10%: P[PTH versus control]=0.011, P[PTH versus migraine]=0.003]; and (3) more hemispheric asymmetries (P[PTH versus control]=0.023, P[PTH versus migraine]=0.57). Lower mean initial slope indices and hemispheric asymmetry (mean interhemispheric Flow difference ≥3.2%) predicted PTH over control (P=0.023 and 0.002, respectively). Lower mean initial slope indices predicted PTH over migraine (P=0.002). Conclusions.-Patients with PTH have reduced regional Cerebral Blood Flow, and regional and hemispheric asymmetries. These Cerebral hemodynamic alterations support an organic basis to chronic posttraumatic headache.
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Cerebral Blood Flow in chronic posttraumatic headache.
Headache, 1997Co-Authors: Stephanie J. Gilkey, Nabih M. Ramadan, Taruna K. Aurora, K. M A WelchAbstract:Background and Purpose.-Headache is the most common neurologic symptom following minor closed head injury. There is often a lack of objective evidence supporting an organic basis of Cerebral pathology in these cases. This pilot study considers the possibility of alterations in Cerebral Blood Flow, indicating evidence of an organic disorder in posttraumatic headache. Methods.-Regional Cerebral Blood Flow studies of 35 patients with chronic posttraumatic headache (PTH) (International Headache Society criteria), identified retrospectively from our Cerebral Blood Flow data base, were compared with those of 49 nonheadache controls and 92 migraineurs (Ad Hoc Committee criteria). Regional Cerebral Blood Flow (initial slope index method) was measured using the xenon Xe 133 inhalation technique. Results.-Compared to migraineurs and controls, and after adjusting for differences (analysis of covariance) in baseline variables such as Blood pressure, hematocrit, and Pco 2 , patients with PTH had: (1) significantly lower mean initial slope indices (P
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Cerebral Blood Flow and neuropsychological asymmetries in unilateral stroke.
Stroke, 1991Co-Authors: G. G. Brown, James R. Ewing, Wendy M. Robertson, K. M A WelchAbstract:This study sought to determine the degree of agreement between asymmetries of neuropsychological functioning and nine methods of quantifying asymmetries of regional Cerebral Blood Flow. The regional Cerebral Blood Flow methods combined three markers of Cerebral Blood Flow asymmetry (percent hemispheric difference, maximum percent probe-pair asymmetry, and number of probe-pair asymmetries) with three indexes of regional Cerebral Blood Flow (fast compartment Flow, initial slope index, and initial slope). Eleven patients with left hemispheric ischemic strokes and 13 with right hemispheric ischemic strokes were studied with the xenon-133 inhalation technique and neuropsychological tests. Blind clinical judgments of neuropsychological asymmetry significantly correlated with all nine methods of Cerebral Blood Flow asymmetry determination; correlations ranged from -0.42 to -0.77. Clinical judgment of asymmetry of neuropsychological functioning accurately predicted the hemisphere of lower Flow in 71-92% of cases, depending on the method of Cerebral Blood Flow asymmetry determination. Agreement between Cerebral Blood Flow and neurobehavioral signs of asymmetry was greater for initial slope and initial slope index than for the fast Flow index. The initial slope and initial slope index showed equally good agreement. The use of the number of asymmetrical probe pairs to detect Cerebral Blood Flow asymmetries agreed less well with neurobehavioral asymmetry than did the other two markers studied. Both the initial slope index and the initial slope measures of Cerebral Blood Flow are useful in predicting neuropsychological asymmetries, especially when the magnitude of the asymmetry is taken into account.
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19F NMR imaging of Cerebral Blood Flow.
Magnetic resonance in medicine, 1991Co-Authors: Craig A. Branch, James R. Ewing, J. A. Helpern, K. M A WelchAbstract:Techniques for the quantitative imaging assessment of Cerebral Blood Flow are presented in a cat using 19F NMR imaging of trifluoromethane. The input function of the indicator was acquired noninvasively, while its uptake and clearance were followed in 2-cc volume voxels from images acquired at 67 sintervals. A single compartment model yielded normal Cerebral Blood Flow estimates. © 1991 Academic Press, Inc.
Susan Wilson - One of the best experts on this subject based on the ideXlab platform.
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Effect of labor on maternal Cerebral Blood Flow velocity
American Journal of Obstetrics and Gynecology, 1998Co-Authors: Keith Williams, Susan WilsonAbstract:Abstract OBJECTIVE: Our purpose was to determine the effect of contractions and second-stage pushing on Cerebral Blood Flow velocity as an indirect assessment of Cerebral hemodynamic changes during labor and delivery. STUDY DESIGN: A prospective cohort of 15 normotensive patients in early labor had maternal middle Cerebral Blood Flow velocity assessed continuously with transcranial Doppler ultrasonography. Assessment was performed during the peak of a contraction, during the trough of a contraction, and with pushing in the second stage. We assessed systolic, diastolic, mean Cerebral Blood Flow velocity (in centimeters per second), and pulsatility index over four contractions. We used analysis of variance to compare velocities at these three stages. RESULTS: Mean maternal Cerebral Blood Flow velocity fell significantly (61.2 ± 6.4, 50 ± 10.2, 52.2 ± 6.5 cm/sec) ( p p CONCLUSIONS: Middle Cerebral vessels vasodilated during the peak of contractions and second-stage pushing as assessed by transcranial Doppler ultrasonography. Pushing in the second stage with the Valsalva maneuver does not expose the patient to a greater risk for middle Cerebral vasospasm than contractions developing in the first stage. (Am J Obstet Gynecol 1998;178:59-61.)
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Maternal Cerebral Blood Flow changes associated with eclampsia.
American Journal of Perinatology, 1995Co-Authors: Keith Williams, Susan WilsonAbstract:To determine whether there is a difference in middle Cerebral Blood Flow velocity in eclampsia compared to a match control of severe preeclamptic patients in the peripartum phase. Three eclamptic and six preeclamptic women had maternal middle Cerebral Blood Flow velocity assessed antepartum and at 24 and 48 hours postpartum. We compared the effect of an eclamptic convulsion on Cerebral Blood Flow velocity changes using analysis of variance. Cerebral Blood Flow velocity was significantly higher in eclamptic than in preeclamptic women (p < 0.01) and rose significantly in the post-convulsive phase. Cerebral Blood Flow velocity was significantly elevated in eclamptic women compared with preeclamptic women in a setting of minimal change in mean arterial pressure.
Guido Rosadini - One of the best experts on this subject based on the ideXlab platform.
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Regional Cerebral Blood Flow in chronic hypertension. A correlative study.
Stroke, 1993Co-Authors: Flavio Nobili, Guido Rodriguez, S Marenco, F. De Carli, M Gambaro, C Castello, Roberto Pontremoli, Guido RosadiniAbstract:Cerebral hypoperfusion has occasionally been reported during essential hypertension. We explored regional Cerebral Blood Flow in a large series of neurologically asymptomatic hypertensive patients to determine relations among Cerebral Blood Flow, concomitant main vascular risk factors, and the most common signs of end-organ damage.Regional Cerebral Blood Flow was measured by the 133Xe inhalation method in 101 hypertensive patients without clinically apparent central nervous system involvement, including 39 mild to moderate untreated and 62 mild to severe treated patients.Compared with age- and sex-matched normal control subjects, Cerebral Blood Flow was significantly reduced in untreated hypertensive patients (P < .01) and to a lesser extent in treated patients (P = .047). Both regional and global Cerebral Blood Flow reductions were observed in approximately one third of patients in both groups. Analysis of variance failed to show significant correlations between Cerebral Blood Flow and total cholesterol ...
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Regional Cerebral Blood Flow in chronic stroke patients.
Stroke, 1993Co-Authors: Guido Rodriguez, Flavio Nobili, S Marenco, F. De Carli, S Francione, Maria Assunta Celestino, Khalil Hassan, Guido RosadiniAbstract:The aim of this study was to investigate regional Cerebral Blood Flow parameters during the postacute phase of unilateral ischemic stroke and to correlate them with clinical data.Regional Cerebral Blood Flow was measured in 187 patients in the stabilized phase of stroke by the xenon-133 inhalation method with 32 extracranial detectors. Thirty-eight patients were reexamined after a mean +/- SD time of 32 +/- 21.4 months.The overall detection of hypoperfusion was 92.0%, with asymmetries as the most sensitive index, especially for patients with a lesser degree of neurological disability. Neurological disability score was strongly associated with regional Cerebral Blood Flow in the affected hemisphere (p < 0.0001) and with asymmetries (p < 0.0001). The presence of carotid obstruction further decreased the regional Cerebral Blood Flow in the affected hemisphere and significantly increased asymmetry (p < 0.0001). Subjects who had no hypoperfusion at absolute values analysis were more frequently free of carotid ...
Guido Rodriguez - One of the best experts on this subject based on the ideXlab platform.
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Cerebral Blood Flow reserve in patients with syndrome X.
Coronary artery disease, 1996Co-Authors: Claudio Brunelli, Flavio Nobili, Paolo Spallarossa, Luca Olivotti, P. Rossettin, Guido Rodriguez, S. CaponnettoAbstract:BACKGROUND: Patients with syndrome X frequently show disorders of oesophageal motility, bronchial reactivity or impaired vasodilator capacity of peripheral vascular beds. For these reasons, it has been suggested that syndrome X may represent a generalized abnormality of vascular and non-vascular smooth muscle function, rather than an isolated coronary problem. OBJECTIVE: To measure the Cerebral Blood Flow and cerebrovascular vasodilator reserve in syndrome X patients and in controls. METHODS: We measured the Cerebral Blood Flow and cerebrovascular reserve in 16 patients with syndrome X [11 women, aged 59.5 +/- 10.8 years (mean +/- SD)] and in 16 age-matched healthy volunteers. No patients had evidence of stenoses of carotid and vertebral arteries on Doppler sonography. Cerebral Blood Flow was measured by the 133Xe inhalation method, using the initial slope index as the Cerebral Blood Flow index. After a baseline measurement, a second Cerebral Blood Flow measurement was performed 20 min after administration of 10 mg/kg acetazolamide intravenously. Acetazolamide is known to be a potent Cerebral vasodilator. The percentage increase in Cerebral Blood Flow after acetazolamide administration was considered an index of cerebrovascular vasodilator reserve. RESULTS: Under basal conditions, both regional and global Cerebral Blood Flow were nearly identical in the control group and in the patient group (initial slope index 50.2 +/- 3.8 versus 50.3 +/-6.2, NS). After acetazolamide administration, the Cerebral Blood Flow increase was 29.0 +/- 14% in the patient group and 29.5 +/- 11% in the control group (NS). CONCLUSIONS: Our data show that Cerebral Blood Flow and cerebrovascular vasodilator reserve were preserved in a series of patients with syndrome X. These results are not consistent with the hypothesis of a diffuse smooth muscle disorder.
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Regional Cerebral Blood Flow in chronic hypertension. A correlative study.
Stroke, 1993Co-Authors: Flavio Nobili, Guido Rodriguez, S Marenco, F. De Carli, M Gambaro, C Castello, Roberto Pontremoli, Guido RosadiniAbstract:Cerebral hypoperfusion has occasionally been reported during essential hypertension. We explored regional Cerebral Blood Flow in a large series of neurologically asymptomatic hypertensive patients to determine relations among Cerebral Blood Flow, concomitant main vascular risk factors, and the most common signs of end-organ damage.Regional Cerebral Blood Flow was measured by the 133Xe inhalation method in 101 hypertensive patients without clinically apparent central nervous system involvement, including 39 mild to moderate untreated and 62 mild to severe treated patients.Compared with age- and sex-matched normal control subjects, Cerebral Blood Flow was significantly reduced in untreated hypertensive patients (P < .01) and to a lesser extent in treated patients (P = .047). Both regional and global Cerebral Blood Flow reductions were observed in approximately one third of patients in both groups. Analysis of variance failed to show significant correlations between Cerebral Blood Flow and total cholesterol ...
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Regional Cerebral Blood Flow in chronic stroke patients.
Stroke, 1993Co-Authors: Guido Rodriguez, Flavio Nobili, S Marenco, F. De Carli, S Francione, Maria Assunta Celestino, Khalil Hassan, Guido RosadiniAbstract:The aim of this study was to investigate regional Cerebral Blood Flow parameters during the postacute phase of unilateral ischemic stroke and to correlate them with clinical data.Regional Cerebral Blood Flow was measured in 187 patients in the stabilized phase of stroke by the xenon-133 inhalation method with 32 extracranial detectors. Thirty-eight patients were reexamined after a mean +/- SD time of 32 +/- 21.4 months.The overall detection of hypoperfusion was 92.0%, with asymmetries as the most sensitive index, especially for patients with a lesser degree of neurological disability. Neurological disability score was strongly associated with regional Cerebral Blood Flow in the affected hemisphere (p < 0.0001) and with asymmetries (p < 0.0001). The presence of carotid obstruction further decreased the regional Cerebral Blood Flow in the affected hemisphere and significantly increased asymmetry (p < 0.0001). Subjects who had no hypoperfusion at absolute values analysis were more frequently free of carotid ...
Keith Williams - One of the best experts on this subject based on the ideXlab platform.
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Effect of labor on maternal Cerebral Blood Flow velocity
American Journal of Obstetrics and Gynecology, 1998Co-Authors: Keith Williams, Susan WilsonAbstract:Abstract OBJECTIVE: Our purpose was to determine the effect of contractions and second-stage pushing on Cerebral Blood Flow velocity as an indirect assessment of Cerebral hemodynamic changes during labor and delivery. STUDY DESIGN: A prospective cohort of 15 normotensive patients in early labor had maternal middle Cerebral Blood Flow velocity assessed continuously with transcranial Doppler ultrasonography. Assessment was performed during the peak of a contraction, during the trough of a contraction, and with pushing in the second stage. We assessed systolic, diastolic, mean Cerebral Blood Flow velocity (in centimeters per second), and pulsatility index over four contractions. We used analysis of variance to compare velocities at these three stages. RESULTS: Mean maternal Cerebral Blood Flow velocity fell significantly (61.2 ± 6.4, 50 ± 10.2, 52.2 ± 6.5 cm/sec) ( p p CONCLUSIONS: Middle Cerebral vessels vasodilated during the peak of contractions and second-stage pushing as assessed by transcranial Doppler ultrasonography. Pushing in the second stage with the Valsalva maneuver does not expose the patient to a greater risk for middle Cerebral vasospasm than contractions developing in the first stage. (Am J Obstet Gynecol 1998;178:59-61.)
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Maternal Cerebral Blood Flow changes associated with eclampsia.
American Journal of Perinatology, 1995Co-Authors: Keith Williams, Susan WilsonAbstract:To determine whether there is a difference in middle Cerebral Blood Flow velocity in eclampsia compared to a match control of severe preeclamptic patients in the peripartum phase. Three eclamptic and six preeclamptic women had maternal middle Cerebral Blood Flow velocity assessed antepartum and at 24 and 48 hours postpartum. We compared the effect of an eclamptic convulsion on Cerebral Blood Flow velocity changes using analysis of variance. Cerebral Blood Flow velocity was significantly higher in eclamptic than in preeclamptic women (p < 0.01) and rose significantly in the post-convulsive phase. Cerebral Blood Flow velocity was significantly elevated in eclamptic women compared with preeclamptic women in a setting of minimal change in mean arterial pressure.