RESUMEN
OBJECTIVE: The purpose of this study was to clarify the difference between cerebral blood flow (CBF) by perfusion computed tomography (CT) and that by xenon-enhanced CT (Xe-CT) through simultaneous measurement. METHODS: Xenon-enhanced CT and perfusion CT were continually performed on 7 normal subjects. Ratios of CBF by perfusion CT (P-CBF) to CBF by Xe-CT (Xe-CBF) were measured for 5 arterial territories; 3 were territories of 3 major arteries (the anterior [ACA], middle [MCA], and posterior [PCA] cerebral arteries), and the other 2 were areas of the thalamus and putamen. RESULTS: The ratios were 1.30 +/- 0.10, 1.26 +/- 0.15, 1.61 +/- 0.15, 0.801 +/- 0.087, and 0.798 +/- 0.080 for the ACA, MCA, PCA, thalamus, and putamen, respectively. Although a good correlation was observed between P-CBF and Xe-CBF for each territory, the ratios were significantly different (P < 0.0001) between 3 territory groups (group 1: ACA and MCA, group 2: PCA, and group 3: thalamus and putamen). CONCLUSIONS: The difference in the ratio of P-CBF to Xe-CBF between the 3 territory groups was considered to result principally from the features of P-CBF. To evaluate P-CBF properly, its territorial characteristics should be taken into account.
Asunto(s)
Encéfalo/irrigación sanguínea , Angiografía Cerebral , Medios de Contraste , Aumento de la Imagen , Procesamiento de Imagen Asistido por Computador , Tomografía Computarizada por Rayos X , Xenón , Adulto , Anciano , Ganglios Basales/irrigación sanguínea , Velocidad del Flujo Sanguíneo/fisiología , Arterias Cerebrales/diagnóstico por imagen , Senos Craneales/diagnóstico por imagen , Femenino , Cefalea/diagnóstico por imagen , Humanos , Aneurisma Intracraneal/diagnóstico por imagen , Masculino , Persona de Mediana Edad , Putamen/irrigación sanguínea , Flujo Sanguíneo Regional/fisiología , Sensibilidad y Especificidad , Tálamo/irrigación sanguínea , Vértigo/diagnóstico por imagenRESUMEN
Cerebral blood flow (ml/min/100g) (CBF) was detected by two methods, static xenon inhalation dynamic CT (Xe-CT) and perfusion CT, and a comparison of these two methods (Xe-CBF and perfusion CBF) was carried out in the same cases. Xe CT used 30% static xenon, 4 min wash-in, and 5 min wash-out, while perfusion CT was done by injecting 30 ml of non-ionic contrast medium at a rate of 9 ml/sec. Forty-eight patients underwent these examinations (30 serious cases and 18 mild). The correlation coefficients in the hemispheric area were r=0.713 (p<0.01) with Xe-CBF and perfusion CBF in mild cases and r=0.567 (p<0.01) in serious cases. The two CBF values were especially disparate in serious cases. The value for perfusion CBF was almost double that of Xe-CBF in these cases. Perfusion CT was a useful examination for the detection of CBF, but in serious cases, CBF needs to be determined by Xe-CT as well.
Asunto(s)
Enfermedad Cerebrovascular de los Ganglios Basales/diagnóstico por imagen , Enfermedad Cerebrovascular de los Ganglios Basales/fisiopatología , Circulación Cerebrovascular , Medios de Contraste , Tomografía Computarizada por Rayos X/métodos , Xenón , Administración por Inhalación , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Índice de Severidad de la Enfermedad , Xenón/administración & dosificaciónRESUMEN
PURPOSE: Cerebral blood blow (ml/100g/min) (CBF) and cerebral blood volume (%) (CBV) were determined in 102 patients (68 men and 34 women; average age, 55.6 years) with diagnostic cerebral blood flow accident. METHODS: CBF was obtained by xenon inhalation computed tomography (Xe CT) and transit time (TT) by perfusion CT. CBV was calculated under the expression CBV=CBF x TT. The patients were divided into three categories: mild (outpatient), moderate (inpatient), and serious (dead), and CBF and CBV were compared between categories. RESULTS: On regions of interest (ROI) in the thalamus, the value for mild cases was 58.8+/-10.4 ml/100g/min (CBF) and that for moderate cases was 40.2+/-19.4, a significant difference. In serious cases, CBV was decreased in the thalamus, but there was no difference in CBF between mild and moderate cases. CONCLUSION: CBV was useful for determining prognosis in severe cases of diagnostic cerebral blood flow accident.
Asunto(s)
Circulación Cerebrovascular , Tomografía Computarizada por Rayos X/métodos , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Accidente Cerebrovascular/diagnóstico por imagen , Accidente Cerebrovascular/fisiopatología , XenónRESUMEN
The objective of this work is to propose a quantitative cerebral blood flow (CBF) calculation method for xenon CT (Xe-CT) by logically estimating the time course change rate (rate constant) of the arterial xenon concentration from that of end-tidal xenon concentration. A single factor, gamma (gamma), which is considered to reflect the diffusing capacity of the lung for xenon, was introduced to correlate the end-tidal rate constant (Kend-tidal) with the arterial rate constant (Karterial). When an appropriate value is given to gamma, it is possible to calculate the arterial rate constant (calculated Karterial) from Kend-tidal. A procedure was developed to determine the gamma value utilizing the characteristics of white matter lambda (lambda). This procedure was applied to three healthy volunteers. The gamma gammaalues for the three subjects were consistent with those directly calculated from end-tidal and arterial (abdominal aorta) xenon data. Hemispheric CBF values with use of calculated Karterial (47.3 +/- 10.3 ml/100 g/min) were close to the reported normative values. We conclude this method could make current Xe-CT examinations substantially reliable and quantitative in measuring CBF.
Asunto(s)
Encéfalo/irrigación sanguínea , Medios de Contraste , Procesamiento de Imagen Asistido por Computador , Tomografía Computarizada por Rayos X , Xenón , Adulto , Aorta Abdominal/diagnóstico por imagen , Velocidad del Flujo Sanguíneo/fisiología , Mapeo Encefálico , Medios de Contraste/farmacocinética , Femenino , Humanos , Masculino , Persona de Mediana Edad , Valores de Referencia , Flujo Sanguíneo Regional/fisiología , Xenón/farmacocinéticaRESUMEN
Perfusion computed tomography (CT) has great value for detecting stroke and evaluating blood flow in the brain. With perfusion CT, it is possible to obtain two absolute values, cerebral blood flow (CBF) (ml/min/100g) and cerebral blood volume (CBV) (%). In using this examination, the main problem is the method of iodine injection. The maximum slope of time-attenuation curve in organs must be reached before the peak enhancement time of the sagittal sinus. To solve this problem, we used a new method in which total injection volume is 30ml, and the rate of injection is 9ml/sec. The data acquisition time is one second for each scan, and the time interval is one second, for 20 scans in total. With this method, we can obtain reliable information on blood flow in the damaged brain. The most common examination used for the detection of brain blood flow is single-phased dynamic CT with Xe inhalation. However, the Xe inhalant examination is difficult to use in the routine clinical setting. Perfusion CT will be more useful for the detection of brain blood flow.