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PubMed1984

Influence of dietary selenium on the mutagenic activity of perfusate and bile from rat liver, perfused with 1,1-dimethylhydrazine.

The mutagenic effect of 1,1-dimethylhydrazine (UDMH) was studied in the liver perfusion/cell culture system. Male Wistar rats, fed a selenium-deficient diet with or without selenium supplementation in the drinking water, were used as liver donors. UDMH caused an increased mutation frequency in Chinese hamster V79 cells exposed in the perfusate. The effect was statistically significant with both selenium-deficient and selenium-supplemented livers. With selenium-deficient livers, a significant mutagenic effect was also obtained when V79 cells were treated with bile collected after the administration of UDMH. Bile flow and bile acid excretion were not affected by UDMH treatment of selenium-deficient or selenium-supplemented livers. There was a tendency towards reduced C-oxygenation of N,N-dimethylaniline in microsomes from selenium-deficient livers perfused with UDMH. The lactate/pyruvate ratio in the perfusate was increased by UDMH, the effect being more pronounced with selenium-deficient than selenium-supplemented livers.

Aniline Compounds↗

PubMed2006

Detection of regional blood perfusion changes in epileptic seizures with dynamic brain perfusion CT--a pilot study.

BACKGROUND AND PURPOSE: Perfusion CT (P-CT) is used for acute stroke management, not, however, for evaluating epilepsy. To test the hypothesis that P-CT may identify patients with increased regional cerebral blood flow during subtle status epilepticus (SSE), we compared P-CT in SSE to different postictal conditions. METHODS: Fifteen patients (mean age 47 years, range 21-74) underwent P-CT immediately after evaluation in our emergency room. Asymmetry indices between affected and unaffected hemispheres were calculated for regional cerebral blood volume (rCBV), regional cerebral blood flow (rCBF), and mean transit time (MTT). Regional perfusion changes were compared to EEG findings. RESULTS: Three patients in subtle status epilepticus (group 1) had increased regional perfusion with electro-clinical correlate. Six patients showed postictal slowing on EEG corresponding to an area of regional hypoperfusion (group 2). CT and EEG were normal in six patients with a first epileptic seizure (group 3). Cluster analysis of asymmetry indices separated SSE from the other two groups in all three parameters, while rCBF helped to distinguish between chronic focal epilepsies and single events. CONCLUSION: Preliminary results indicate that P-CT may help to identify patients with SSE during emergency workup. This technique provides important information to neurologists or emergency physicians in the difficult clinical differential diagnosis of altered mental status due to subtle status epilepticus.

Adult↗

PubMed2005

High-frequency QRS electrocardiogram predicts perfusion defects during myocardial perfusion imaging.

BACKGROUND: Changes in high-frequency (HF) QRS components of the electrocardiogram (ECG) (150-250 Hz) are more sensitive than changes in conventional ST segments for detecting myocardial ischemia. We investigated the accuracy of 12-lead HF QRS ECG in detecting perfusion defects during adenosine tetrofosmin myocardial perfusion imaging (MPI). METHODS AND RESULTS: 12-lead HF QRS ECG recordings were obtained from 45 patients before and during adenosine technetium Tc 99m tetrofosmin MPI tests. Before the adenosine infusions, recordings of HF QRS were analyzed according to a morphologic score that incorporated the number, type, and location of reduced amplitude zones (RAZs) present in the 12 leads. During the adenosine infusions, recordings of HF QRS were analyzed according to the maximum percentage changes (in both the positive and negative directions) that occurred in root mean square voltage amplitudes within the 12 leads. The best set of prospective HF QRS criteria had a sensitivity of 94% and a specificity of 83% for correctly identifying the MPI result. The sensitivity of simultaneous ST-segment changes (18%) was significantly lower than that of any individual HF QRS criterion (P < .001). CONCLUSIONS: Analysis of 12-lead HF QRS ECG is highly sensitive and reasonably specific for detecting perfusion defects during adenosine MPI stress tests and significantly more sensitive than analysis of conventional ST segments.

Adenosine↗

PubMed2005

[Quantitative relationships between ADC and perfusion changes in acute ischemic stroke using combined diffusion-weighted imaging and perfusion MR (DWI/PMR)].

UNLABELLED: MR-based diffusion- and perfusion-weighted imaging (DWI/PWI) has become the standard imaging technique to assess the individual brain pathophysiological status in acute ischemic stroke. The finding of a "mismatch" with larger PWI than DWI abnormality is thought to reflect the presence of tissue at-risk of infarction, i.e., penumbra. However, there has been no detailed study of the quantitative relationships between perfusion and diffusion changes in stroke patients. According to the experimental concept of penumbra, the ADC would be expected to remain unchanged despite decreasing perfusion until a critical threshold is reached. We have tested this hypothesis directly in man. METHODS: DWI/PWI was performed in 7 patients with MCA territory stroke within 4-10 hrs from onset. Mismatch was defined on diffusion and rMTT maps, and circular ROIs were positioned within the ADC lesion (D), the mismatch area (M), and the normal appearing cortex (N); mirror ROIs were also obtained, and affected/unaffected ratios for ADC and rCBF were computed for each ROI. RESULTS: The mean (+/-1 SD) ADC ratios were 0.60 +/- 0.09, 0.95 +/- 0.10 and 1.02 +/- 0.04 in L, M and N, respectively; the corresponding rCBF ratios were 0.32 +/- 0.12, 0.75 +/- 0.14 and 0.97 +/- 0.09, respectively. The relationship was non-linear, with the rCBF but not the ADC ratio for M being significantly lower (p < 0.01) than that for N. A threshold for decline in ADC was apparent around 0.50 rCBF ratio. COMMENT: These results directly document in man that the ADC declines only after hypoperfusion has reached a certain degree (about 50%), consistent with the concept of the ischaemic penumbra.

Acute Disease↗

PubMed2005

Foot pulse oximeter perfusion index correlates with calf muscle perfusion measured by near-infrared spectroscopy in healthy neonates.

OBJECTIVE: In critically ill neonates, peripheral perfusion and oxygenation assessment may provide indirect information on the circulatory failure of vital organs during circulatory shock. The development of pulse oximetry has recently made it possible to calculate the perfusion index (PI), obtained from the ratio between the pulsatile and nonpulsatile signals of absorbed light. The main goals of this study were: (1) to study foot PI; and (2) to evaluate the relationship between foot PI, obtained continuously by pulse oximetry, and a number of variables, i.e. blood flow (BF), oxygen delivery (DO(2)), oxygen consumption (VO(2)), and fractional oxygen extraction (FOE), measured indirectly by near-infrared spectroscopy (NIRS) on the calf in 43 healthy term neonates (weight 3474.6 +/- 466.9 g; gestational age 39.1 +/- 1.4 weeks). STUDY DESIGN: Calf BF, DO(2) and VO(2) were assessed by NIRS on short-lived venous and arterial occlusion maneuvers. PI was measured on the contralateral foot. RESULTS: Foot PI was 1.26 +/- 0.39. There was a positive correlation between foot PI and both calf BF (r = 0.32, p = 0.03) and DO(2) (r = 0.32, p = 0.03), but no correlation was found between foot PI and calf FOE and between foot PI and VO(2). CONCLUSIONS: In the neonatal intensive care unit, continuously measuring foot PI by pulse oximetry seems clinically more feasible for peripheral perfusion monitoring than spot measurements of the calf BF and/or VO(2) by indirect NIRS.

Foot↗

PubMed2004

Myocardial perfusion imaging using OMNISCAN: a dose finding study for visual assessment of stress-induced regional perfusion abnormalities.

BACKGROUND: Different doses of contrast agent are applied for magnetic resonance perfusion studies and mainly semiquantitative approaches have been reported for analysis. We aimed to determine the optimal dose for a visual detection of perfusion defects. METHODS: 49 patients (59+/-8 years; 33 male) scheduled for invasive angiography were examined at stress (0.14 mg adenosine/kg body weight/minute) and rest using a TFE-EPI hybrid sequence (Philips ACS NT; 1.5 T). Patients were assigned to three different dose groups of gadodiamide (0.05, 0.1, and 0.15 mmol/kg body weight) injected as a bolus via a peripheral vein. Visual assessment was used to detect a regional reduction of peak signal intensity or speed of contrast agent inflow at stress in comparison to rest. RESULTS: Prevalence for coronary artery disease was 67%. The highest diagnostic accuracy was reached for a dose of 0.1 mmol gadodiamide/kg body weight (86% p=nonsignificant vs. 0.15 and 0.05 mmol gadodiamide/kg). At this dose, no major artifacts related to the contrast agent were found. CONCLUSIONS: Visual assessment of myocardial perfusion using a high-flow rate contrast agent bolus injection and a TFE-EPI sequence can be best achieved with a dose of gadodiamide 0.1 mmol/kg bodyweight.

Aged↗

PubMed2003

Changes in cerebral perfusion precede plaque formation in multiple sclerosis: a longitudinal perfusion MRI study.

New MRI techniques such as the analysis of magnetization transfer or diffusion have provided evidence for subtle progressive alterations in tissue integrity prior to focal leakage of the blood-brain barrier (BBB) as part of plaque formation in multiple sclerosis. Since inflammation is capable of modulating the microcirculation, we investigated the hypothesis that changes in the local perfusion might be one of the earliest signs of lesion development. 20 patients with definite relapsing-remitting multiple sclerosis were analysed with regard to cerebral blood volume, cerebral blood flow, mean transit time and apparent diffusion coefficient (ADC), as well as conventional MRI parameters, on monthly follow-up scans. Among 89 gadolinium-enhancing lesions, we selected 18 that developed during the study and met strict inclusion criteria. In these, changes of perfusion parameters were detectable not only prior to the BBB breakdown, but also prior to increases in the ADC. Our data indicate that inflammation is accompanied by altered local perfusion, which can be detected prior to permeability of the BBB.

Adult↗

PubMed2000

Effects of perfusion pressure on tissue perfusion in septic shock.

OBJECTIVE: To measure the effects of increasing mean arterial pressure (MAP) on systemic oxygen metabolism and regional tissue perfusion in septic shock. DESIGN: Prospective study. SETTING: Medical and surgical intensive care units of a tertiary care teaching hospital. PATIENTS: Ten patients with the diagnosis of septic shock who required pressor agents to maintain a MAP > or = 60 mm Hg after fluid resuscitation to a pulmonary artery occlusion pressure (PAOP) > or = 12 mm Hg. INTERVENTIONS: Norepinephrine was titrated to MAPs of 65, 75, and 85 mm Hg in 10 patients with septic shock. MEASUREMENTS AND MAIN RESULTS: At each level of MAP, hemodynamic parameters (heart rate, PAOP, cardiac index, left ventricular stroke work index, and systemic vascular resistance index), metabolic parameters (oxygen delivery, oxygen consumption, arterial lactate), and regional perfusion parameters (gastric mucosal Pco2, skin capillary blood flow and red blood cell velocity, urine output) were measured. Increasing the MAP from 65 to 85 mm Hg with norepinephrine resulted in increases in cardiac index from 4.7+/-0.5 L/min/m2 to 5.5+/-0.6 L/min/m2 (p < 0.03). Arterial lactate was 3.1+/-0.9 mEq/L at a MAP of 65 mm Hg and 3.0+/-0.9 mEq/L at 85 mm Hg (NS). The gradient between arterial P(CO2) and gastric intramucosal Pco2 was 13+/-3 mm Hg (1.7+/-0.4 kPa) at a MAP of 65 mm Hg and 16+/-3 at 85 mm Hg (2.1+/-0.4 kPa) (NS). Urine output at 65 mm Hg was 49+/-18 mL/hr and was 43+/-13 mL/hr at 85 mm Hg (NS). As the MAP was raised, there were no significant changes in skin capillary blood flow or red blood cell velocity. CONCLUSIONS: Increasing the MAP from 65 mm Hg to 85 mm Hg with norepinephrine does not significantly affect systemic oxygen metabolism, skin microcirculatory blood flow, urine output, or splanchnic perfusion.

Aged↗

PubMedDate not supplied

Evaluation of cerebral perfusion parameters measured by perfusion CT in chronic cerebral ischemia: comparison with xenon CT.

PURPOSE: The purpose of this work was to evaluate the usefulness of perfusion CT in the evaluation of patients with chronic cerebral ischemia by comparing it with xenon CT (Xe-CT). METHOD: Cerebral blood flow (CBF) of perfusion CT (CBFper) and time to peak (TTP) were compared with the CBF of Xe-CT (CBFxe) in 18 patients. Cerebral blood volume (CBV) was compared with cerebral vascular reserve (CVR) in 10 of 18 patients who underwent pre- and postacetazolamide Xe-CT. RESULTS: CBFper and TTP demonstrated a high correlation with CBFxe in relative values by side-to-side comparisons (r = 0.743, p < 0.0001 and r = -0.760, p < 0.0001, respectively). There was a negative correlation between relative CBV and relative CVR (r = -0.637, p = 0.0025). Visually, territories with delayed TTP corresponded well to those of decreased CBFxe, but these territories tended to be larger in TTP maps. CONCLUSION: Perfusion CT is a useful tool to evaluate chronic hemodynamic disturbance and can be an alternative method for those using acetazolamide challenge.

Adult↗

PubMed2000

Poststress measurements of left ventricular function with gated perfusion SPECT: comparison with resting measurements by using a same-day perfusion-function protocol.

PURPOSE: To investigate the relationship between the development of ischemia during stress testing and the changes in left ventricular ejection fraction (LVEF) measurements obtained after stress and at rest with a same-day perfusion-function imaging protocol. MATERIALS AND METHODS: One hundred twenty-six patients underwent a same-day rest-stress (61%) or stress-rest (39%) protocol and gated single photon emission computed tomography (SPECT). Perfusion analysis was performed with a 12-segment model. Defects were scored (0 = no defect, 1 = mild defect, 2 = moderate defect, and 3 = severe defect); differences between the summed stress and resting scores of greater than three indicated substantial ischemia. RESULTS: Resting and poststress LVEFs correlated significantly (r = 0.97, P <.001); however, patients with and patients without ischemia had significant differences in poststress versus resting LVEFs (-4.0 vs 1.0, respectively; P <.01). In patients with ischemia versus patients without ischemia, subgroup analysis stress-rest (-2.5 vs 1.0, P =.047) and rest-stress (-4.0 vs 1.0, P =.006) protocols yielded similar results. CONCLUSION: In patients with clinically important stress-induced perfusion abnormalities, the LVEF after stress was significantly lower than the LVEF at rest with same-day rest-stress and stress-rest imaging protocols. In the clinical setting, poststress LVEFs may be lower than true resting measurements, particularly in patients with moderate to severe stress-induced ischemia.

Adenosine↗

PubMed1990

Contributions of liver perfusion flow rate and enzyme inhibition to altered verapamil clearance with halothane: a study in the isolated perfused rat liver.

Verapamil clearance is reduced during halothane administration. This study evaluated relative contributions of reduced hepatic flow rate and hepatic metabolizing enzyme inhibition by halothane as a cause of reduced verapamil clearance. An isolated perfused rat liver model was utilized in which flow rate could be fixed during halothane administration. Perfusions were performed on five to six livers under each of the following conditions: (a) control--40 mL/min flow rate with no anesthetic exposure; (b) 1.5% halothane--40 mL/min; (c) 2.25% halothane--40 mL/min; (d) reduced flow--20 mL/min with no anesthetic exposure; and (e) reduced flow with 1.5% halothane--20 mL/min. Halothane caused dose-dependent decreases in both total hepatic and intrinsic clearance rates (P less than 0.05). With no anesthetic exposure, a flow reduction of 50% (20 mL/min) also gave a large reduction (P less than 0.05) in hepatic clearance of verapamil compared with the control condition (40 mL/min). The addition of 1.5% halothane to the reduced flow condition was not associated with further reduction in hepatic clearance rate. Results of this study suggest that although both reduced hepatic perfusion and hepatic enzymatic inhibition by halothane administration are associated with decreased verapamil clearance, a greater proportion of this decrease appears to be due to reductions in hepatic flow. The present results may apply to other drugs used in anesthesia that have high hepatic extraction ratios; thus, clearance of these drugs may be more dependent on hepatic blood flow than on hepatic enzyme activity.

Animals↗

PubMed2005

Myocardial perfusion imaging using adenosine triphosphate stress multi-slice spiral computed tomography: alternative to stress myocardial perfusion scintigraphy.

BACKGROUND: The present study was designed to: (i) detect myocardial ischemia in contrast enhanced multi-slice spiral computed tomography (CE-MSCT) using adenosine triphosphate (ATP) pharmacological stress test; and (ii) evaluate the potential of ATP stress CE-MSCT in a clinical setting. METHODS AND RESULTS: Twelve patients underwent ATP stress CE-MSCT and stress thallium-201 myocardial perfusion scintigraphy (MPS) and 9 of the patients received conventional coronary angiography (CAG). Dual CE-MSCT scans were performed for stress and rest images, with and without intravenous infusion of ATP (0.16 mg.kg-1.min-1) at intervals of 20 min. Myocardial perfusion and coronary artery were visually evaluated using MSCT and compared the results obtained from MPS and CAG. Of 36 territories, stress images of CE-MSCT described 26 hypo-perfusion areas and MPS described 22 redistributions. The agreement between MSCT and MPS was 83% (30/36, p<0.05). In 141 coronary artery segments of 9 patients undergoing CAG, rest images of CE-MSCT, which had significantly higher assessability than stress images (89% vs 48%, p<0.05), described 76% (13/17) of culprit coronary stenoses. CONCLUSIONS: Although CT-angiography should be currently assessed using rest images, ATP stress CE-MSCT can describe both ATP-induced myocardial ischemia and coronary artery stenoses in patients with coronary artery disease.

Adenosine Triphosphate↗

PubMed1993

Attenuation of myocardial stunning by an increase in the H+ buffering capacity of the perfusate and that by hypoxic preperfusion are affected differently by the free [Ca2+] of the perfusate.

OBJECTIVES: Protons produced during ischemia may increase intracellular Na+ (Na+i) through Na+/H+ exchange, and may lead to Ca2+ overload through Na+/Ca2+ exchange to cause myocardial stunning. This study investigated whether an increase in the H+ buffering capacity of the perfusate or a reduction of H+ production by a brief hypoxic preperfusion before ischemia would reduce myocardial stunning. We also investigated whether the protective effect of these maneuvers depends on the free [Ca2+] of the perfusate. METHODS: Isolated rat hearts were preperfused with oxygenated or hypoxic buffer (pH 7.4) containing 100 mM of either sucrose or HEPES for 10 min, followed by 15 min of total ischemia and 30 min of reperfusion. To investigate the dependence of the effects of HEPES or a brief hypoxic preperfusion, the free Ca2+ concentration in the buffer was changed from 1.25 mM to 2.5 mM in some hearts. RESULTS: Oxygenated preperfusion with buffer containing HEPES and 1.25 or 2.5 mM Ca2+ improved the metabolic and functional recovery with a decrease in the accumulation of Na+i during ischemia and in 45Ca2+ uptake during reperfusion. A brief hypoxic preperfusion with 1.25 mM Ca2+ provided a similar protective effect whereas no protective effect was observed when the [Ca2+] was raised to 2.5 mM. CONCLUSIONS: An increase in the H+ buffering capacity or a brief hypoxic preperfusion reduced myocardial stunning with improved metabolic recovery, and reduced Ca2+ uptake. However, the effects of these interventions were affected differently by the free [Ca2+] of the perfusate, which suggests that they work, at least in part, through some different mechanism(s).

Animals↗

PubMed2006

Enhanced perfusion in eyes and cerebral perfusion defects in a patient with Fragile X Syndrome.

Fragile X syndrome (FXS) is known as the most common form of inherited mental retardation. In our study, brain perfusion single photon emission computed tomography (SPECT) was performed in a 6 year-old boy diagnosed with FXS. Diffuse bilateral uptake of Technetium-99m hexamethyl propylene amine oxime (99mTc-HMPAO) was noted in his orbits, as well as cortical perfusion defects (hypoperfusion in the right parietal and the left temporal lobe). Ophthalmologic examination showed no pathological findings. Magnetic resonance imaging (MRI) revealed no abnormality in the orbital structures, although hypoplasia of cerebellum and vermis was visualized. Since the patient was crying during the injection, the increased blood flow or the increased metabolism of the eyes and/or ocular muscles may be responsible for this orbital finding. Alternatively, the enhanced uptake of HMPAO in the orbits may reflect the pathology associated with FXS, because patients with FXS might have visual-motor abnormalities. To the best of our knowledge, there has been no report documenting such an orbital uptake of HMPAO. Moreover, the visualization of decreased cerebral perfusion, with the normal findings of MRI, indicates that brain SPECT imaging with HMPAO is helpful for detecting brain abnormalities in children with FXS.

Child↗

PubMed2006

Evaluation of safety and pharmacokinetics of vancomycin after intraosseous regional limb perfusion and comparison of results with those obtained after intravenous regional limb perfusion in horses.

OBJECTIVE: To evaluate the clinical effects and pharmacokinetics of vancomycin in plasma and synovial fluid after intraosseous regional limb perfusion (IORLP) in horses and to compare results with those obtained after IV regional limb perfusion (IVRLP). ANIMALS: 6 horses. PROCEDURES: 1 forelimb of each horse received vancomycin hydrochloride (300 mg in 60 mL of saline [0.9% NaCl] solution) via IORLP; the contralateral limb received 60 mL of saline solution (control). Solutions were injected into the medullary cavity of the distal portion of the third metacarpal bone. Synovial fluid from the metacarpophalangeal (MTCP) and distal interphalangeal (DIP) joints and blood were collected prior to perfusion and 15, 30, 45, 65, and 90 minutes after beginning IORLP, and synovial fluid from the MTCP joint only and blood were collected 4, 8, 12, and 24 hours after beginning IORLP. Plasma urea and creatinine concentrations and clinical appearance of the MTCP joint region and infusion sites were determined daily for 7 days. Results were compared with those of a separate IVRLP study. RESULTS: Clinical complications were not observed after IORLP. Mean vancomycin concentration in the MTCP joint was 4 microg/mL for 24 hours after IORLP. Compared with IORLP, higher vancomycin concentrations were detected in the DIP joint after IVRLP. Compared with IVRLP, higher vancomycin concentrations were detected in the MTCP joint for a longer duration after IORLP. CONCLUSIONS AND CLINICAL RELEVANCE: IORLP with 300 mg of vancomycin in a 0.5% solution was safe and may be clinically useful in horses. Intravenous and intraosseous routes may be better indicated for infectious processes in the DIP and MTCP joints, respectively.

Animals↗

PubMed2002

[Significance of 99mTc-labeled perfusion agents in the simultaneous assessment of myocardial perfusion and cardiac function].

Simultaneous assessment of left ventricular myocardial perfusion and systolic function was accomplished by utilizing ECG-gated myocardial perfusion SPECT. This development in nuclear cardiology will be attributed to the recent advances in new 99mTc-labeled perfusion agents, multi-detector SPECT system and software for automatic edge-detection of the left ventricle. In this article, we described about the clinical utilities of this method in detecting "hibernating myocardium," severe coronary artery disease patients with exercise-induced LV dysfunction, in predicting functional recovery after reperfusion therapy for acute myocardial infarction patients and in diagnosing patients with right heart diseases.

Coronary Circulation↗

PubMed1976

[Regional myocardial perfusion redistribution through coronary drugs. II. Influence of dipyridamole and oxyfedrin on regional perfusion distribution].

The influence of Dipyridamol and Oxyfedrin on regional myocardial precapillary microperfusion patterns was investigated in groups of 15 and 13 patients by means of selective double lable perfusion scintigraphy. Automatic impulse rate integration allows the comparison of different perfusion areas in the same scintigram as well as the comparison of different identical regions in different scintigrams. The scans were taken in two positions (frontal and l.a.o.). Microperfusion patterns were measured before and after the intravenous application of the drug. We found a typical shift of the microperfusion patterns with both medicaments. Under the influence of Oxyfedrin and Dipyridamol there was an increase of the relative microperfusion intensity in the vicinity of the major arteries but there were great differences as to the degree of their reaction maximum. Besides the results of the groups some typical cases are demonstrated. The method allows a satisfactory measurement of differences in the regional precapillary myocardial perfusion under the influence of coronary active drugs. We believe that statements on physiologic and pathologic functions are possible.

Angiocardiography↗

PubMedDate not supplied

Cerebral perfusion alterations during the acute phase of experimental generalized status epilepticus: prediction of survival by using perfusion-weighted MR imaging and histopathology.

BACKGROUND AND PURPOSE: Persistent generalized status epilepticus (SE) is associated with alterations of cerebral perfusion (CP). Because perfusion-weighted MR imaging (PWI) allows noninvasive CP-determination, the aim of this study was to investigate CP alterations during acute experimental SE correlated with SE-induced neuronal cell loss. METHODS: The rat pilocarpine model was used to induce SE. Multilocal PWI was performed before (baseline) and 3, 15, 30, 60, and 120 minutes after onset of SE. Bolus-peak ratio (BPR) was calculated for the retrosplenial and piriform cortex, hippocampus, amygdala, and thalamus and compared with baseline. Neuronal cell loss was quantified at different time points after induction of SE by cresyle violet staining. RESULTS: Immediately after SE onset (3 minutes), BPR temporarily increased to 102%-130% in all regions, with a maximum in the amygdala (129 +/- 16%) and hippocampus (130 +/- 21%). At 15, 30, and 60 minutes, BPR decreased continuously to 57%-76%. BPR values <55% in the parietal and/or temporal cortex resulted in death. In surviving animals, BPR recovered to 66%-79% and there was a good correlation between neuronal cell loss in specific brain regions at 2 weeks after SE onset and maximal decrease in BPR (r > 0.73). CONCLUSION: PWI demonstrated a transient cerebral hyperperfusion immediately after SE onset, followed by a significant continuous decline to different perfusion levels. In our experimental setting, a decline of cortical BPR below 55% of baseline seems to be a prognostic threshold value associated with subsequent death. In surviving animals, there is good correlation between the maximal decrease in BPR in the acute phase of SE and late neuronal cell loss.

Acute Disease↗