Yoshikatsu Seiki

Comparison of cerebral blood flow between perfusion computed tomography and xenon-enhanced computed tomography for normal subjects territorial analysis

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.

Quantitative Cerebral Blood Flow Calculation Method Using White Matter Lambda in Xenon Ct

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 (&ggr;), 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 &ggr;, it is possible to calculate the arterial rate constant (calculated Karterial) from Kend-tidal. A procedure was developed to determine the &ggr; value utilizing the characteristics of white matter lambda (&lgr;). This procedure was applied to three healthy volunteers. The &ggr; &ggr;alues 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.

Early Cerebral Circulation Disturbance in Patients Suffering from Different Types of Severe Traumatic Brain Injury: A Xenon CT and Perfusion CT Study

INTRODUCTION Traumatic brain injury (TBI) is widely known to cause dynamic changes in cerebral blood flow (CBF). In particular, secondary brain insults have been reported to decrease CBF. The purpose of this study was to clarify the cerebral circulation in different types of TBI. METHODS Sixty-nine patients with TBI were divided into four groups, the subdural hematoma group, the contusion/intracerebral hematoma group, the diffuse axonal injury group, and the diffuse brain swelling group. In these patients, we simultaneously performed Xe-CT and perfusion CT to evaluate the cerebral circulation on post-injury days 1-3. We measured CBF using Xe-CT and mean transit time using perfusion CT and calculated the cerebral blood volume using the AZ-7000 W98 computer system. RESULTS There were no significant differences in the Glasgow Coma Scale score on arrival or the Glasgow Outcome Scale score between the groups. The patients who had suffered focal TBI displayed more significant cerebral circulation disturbances than those that had suffered diffuse TBI. We were able to evaluate the cerebral circulation of TBI patients using these parameters. CONCLUSION Moderate hypothermia therapy, which decreases CBF, the cerebral metabolic rate oxygen consumption (CMRO2), and intracranial pressure might be effective against the types of TBI accompanied by cerebral circulation disturbance. We have to use all possible measures including hypothermia therapy to treat severe TBI patients according to the type of TBI that they have suffered.

Early Cerebral Circulation Disturbance in Patients Suffering from Severe Traumatic Brain Injury (TBI): A Xenon CT and Perfusion CT Study.

Traumatic brain injury (TBI) is widely known to cause dynamic changes in cerebral blood flow (CBF). Ischemia is a common and deleterious secondary injury following TBI. Detecting early ischemia in TBI patients is important to prevent further advancement and deterioration of the brain tissue. The purpose of this study was to clarify the cerebral circulatory disturbance during the early phase and whether it can be used to predict patient outcome. A total of 90 patients with TBI underwent a xenon-computed tomography (Xe-CT) and subsequently perfusion CT to evaluate the cerebral circulation on days 1–3. We measured CBF using Xe-CT and mean transit time (MTT: the width between two inflection points [maximum upward slope and maximum downward slope from inflow to outflow of the contrast agent]) using perfusion CT and calculated the cerebral blood volume (CBV) using the AZ-7000W98 computer system. The relationships of the hemodynamic parameters CBF, MTT, and CBV to the Glasgow Coma Scale (GCS) score and the Glasgow Outcome Scale (GOS) score were examined. There were no significant differences in CBF, MTT, and CBV among GCS3–4, GCS5–6, and GCS7–8 groups. The patients with a favorable outcome (GR and MD) had significantly higher CBF and lower MTT than those with an unfavorable one (SD, VS, or D). The discriminant analysis of these parameters could predict patient outcome with a probability of 70.6%. During the early phase, CBF reduction and MTT prolongation might influence the clinical outcome of TBI. These parameters are helpful for evaluating the severity of cerebral circulatory disturbance and predicting the outcome of TBI patients.

Occlusion of the deep cerebral veins

There are very few reports on occlusion of the deep cerebral veins in the adult, and none where cerebroangiography was used. We report here a case of occlusion in the Galen and straight sinuses.

Intra-operative scalp expansion for wound closure without tension in craniosynostosis operation : technical innovation

Primary scalp wound closure using intra-operative scalp expansion in a craniosynostosis operation is described. Since this method enables easy scalp expansion, it is considered to be a useful adjunctive technique which should be taken into account when closing scalp wounds in craniosynostosis surgery, where the risk exists of cranial expansion-induced compression and deformity of the remodelled bone flaps after bone fixation.

The study of systemic general circulation disturbance during the initiation of therapeutic hypothermia: Pit fall of hypothermia

Aims: Neurointensive care has reduced the mortality and improved the outcome of patients for severe brain damage, over recent decades, and made it possible to perform this therapy in safety. However, we have to understand the complications of this therapy well. The purpose of our study was to determine the systemic circulation disturbance during the initiation of therapeutic hypothermia by using this continuous neurointensive monitoring system. Materials and Methods: Ten severe brain damage patients treated with hypothermia were enrolled. All patients had Glasgow Coma Scale (GCS) less than or equal to 8, on admission. Results: We verified that heart rate, cardiac output, and oxygen delivery index (DO2I) decreased with decreasing core temperature. We recognized that depressed cardiac index (CI) was attributed to bradycardia, dehydration, and increased systemic vascular resistance index (SVRI) upon initiation of hypothermia. Conclusion: Although the hypothermia has a therapeutic role in severe brain damage patients, we have to carry out this therapy while maintaining their cardiac output using multimodality monitoring devices during hypothermia period.

Neurointesive Care with Multimodal Monitoring

Head injury is a major cause of disability and death among young people. Neurointensive care has reduced the mortality and improved the outcome after severe traumatic brain over recent decades. The development of neuromonitoring in neurointensive care units has enabled early detection of secondary complications and, thereby reduce secondary brain damage. Neurointensive care units have made advances with continuous neuromonitoring during the past decade. Improvements in neurointensive care have been predominantly in intensification and optimization of already established ways to monitor and treat patients. Primary brain damage is damage sustained immediately on direct impact. Secondary brain damage often results several days after from a secondary brain insult. Modern neurointensive care focus has been on prevention of secondary brain damage. Intracranially, as secondary brain damage advances, we see a rise in intracranial pressure, increased edema, vasospasm and seizure activity. Systemic manifestations of secondary brain damage are anoxia, hypercapnia, hypocapnia, hypotension, hyperthermia and hyperglycemia. In our study we collected the intracranial and systemic clinical effects of brain damage by using our NICU’s advanced monitoring systems. By using this continuous neurointensive monitoring our institution’s goal is to ultimately prevent and to establish effective treatment strategies for secondary brain insult.