Cerebral blood flow change during postcibal hypotension. Comparison between multiple system atrophy and pure autonomic failure

ABSTRACTS

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CEREBRALBLOOD FLOW CHANGE DURINGPOSTCIBALHYPOTENSION. -COMPARISON BETWEEN MULTIPLE SYSTEM ATROPHY AND PURE AUTONOMIC FAILUREY Maruki. M Matsuzaki. A Onoda. Y Narabavashi. K Shimazu. Saitama Neuropsychiatric Institute and Saitama Medical School, Saitama, JAPAN. Obiectives: Autonomic nervous functional and biochemical basis of postcibal hypotension (PH) has been well investigated. To date, however, there has been few studies about cerebral blood flow (CBF) change during PH. The aim of the present study was to evaluate whether and how PH effected on cerebral circulation. Methods: Patients with multiple system atrophy (MSA; 57years, female) and pure autonomic failure (PAF; S8years, male) were subjected to this study. After an overnight fast from midnight, regional CBF (rCBF) was measured before and after 7Sg glucose load (0, 15, 30, 60, 90, 120min) using Xe-CT method (30% Xe gas, 4rain. inhalation). Results: 1.MSA: Mean arterial blood pressure (MABP) decreased from 100mmHg(0min) to 93(15rain), 53(30min), 47(60rain), 47(90min), 67(120min). In parallel with decrease of MA8P, rCBF in the patient with MSA decreased (Fig1). 2. PAF: MABP decreased from126mmHg (0rain) to 112(15rain), 89 (30rain), 90(60rain), 82(90rain), 77(120min). r C B F did not change during PH (Fig2). rCBF did not change during PH sO 1 rCBF d e c r e a s e d d u r i n g PH 50 PAF(Fig2) ............ ~so MSA(Fig 1) 50

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The Diffusion Status of Metabolites in Human Brain: Measured Using Proton Diffusion MR Spectroscopy. Fan~, R a n d . Nishitani Rlrnmul,

Fllrnkl~u Mivoshi.Ms~afnmiHIrada.Ohl~nka |lidekl. I.Dgpl. of Radiology,XiJingHospital.TheFourth Military Medical University giaa (710032),P.R.ofChina 2.Dept.of Radioiog~,,MedicaiSchooI,Tokushima University,Tokushima,lapan Mmterl=l,and Methndl: The watersuppressedSTEAMsequence wereused for localizeddiffusion measurementin 5 normal humanbrain in viva The diffusion gradients(2.4.and 6 roT/M)were applied during the TFJ2 period. corresponding the b factors as 72,285,and 642 s/ramS.Other parameters including the TE=68ms,TM=200ms,TK= 1625msand 256 acquisition.The signal intensity of NAA ,Cho,and Cr were measured and the diffusion coefficient(D) werecalculatedaccordingthe equationD=Ln(SIIS0y(bl-bO) [l~nla:The diffusion coefficientof NAA,Choand Cr werelist in followtable table: The Diffusion Coefficient of NAA,Cho and Cr in the normal human brain white matter.(unit:10 -3 mm2/sec)

Subject I 2 3 4

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NAA

Cho

0262 0.155 0.064 0. Ill 0163

0.185 0084 0,088 0.117 0.125

Cr 0.175 0. I19 0106 0.110 0.146

Conclusion:It was acceptedthat diffusion MR imagingof watercan provide

useful informationabout tissue sLmctureand function.andit has been used in some disease of brain,suchas infarction and brain tumors.But it is unable to discriminatebetween multiple comparh'nant.Watersuppressed diffusion spocttoscopy can reflectsintracellularmetabolitemobility,andsome specific metabolites,like NAA,Cho end Cr may provide future information about physiologic changesof brain diseases.

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Abb.STEAM=stimulated-echoacquisition mode,NAA=N-acetylaspartate. Cho=choline.Cr=creatinr

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Conclusiorl; 1. In parallel with decrease of MABP, rCBF in the patient with MSA decreased, however, rCBF with PAF did not decrease. 2. In the patient with MSA, decrease of rCBF in posterior circulation was more prominent than in anterior circulation.

PROSPECTS OF SURGICAL REMOVAL OF A CONTUSIONAL LESION BY INTRACRANIAL PRESSURE, CEREBRAL BLOOD FLOW AND BRAIN TISSUE pH. Hidehiko Kushi, M.D., Narivuki Havashi, M.D., Takeshi Saitoh, M.D, and Takashi Moriya, M.D. Department of Emergency and Critical Care Medicine, Nihon University School of Medicine. Tokyo, Japan. Objective Decision of surgical removal area of contusional hemorrhage is very difficult at emergency surgery. We examined 8 patients of cerebral contusion, all of whom had previously undergone surgical removal of hematoma. For the determination of the pericontusional edema zone (PEZ), we first utilized the XeCT and dynamic CT to record CBF and CBV, and subsequently conducted a mapping study based on the recordings of latter pair. With regards to the operation, after we had removed the hematoma, several sites of the PEZ were punctured and an original brain tissue pH sensor was used to measure the pH of these areas.

Results

CBF of the PEZ before operation had

exhibited and ischemic level of 12.5"18.7 ml/100g/min. Likewise, CBV was recorded at 2.5-3.6 ml/100g, a value comparatively lower than that of normal brain tissue and significantly lower than that of our institutional standards (6.8--0.37 mt/100g). Brain tissue pH of PEZ was 6.3-7.1 and in state of evident acidosis, necessitating the complete removal of the contusional core. Conclusion These results would therefore indicate that the measument of brain tissue pH as well as the analysis of CBF and CBV are key factors contributing to the determination of the appropriate excisional boundary for contusional hemorrhage.

COMPARISON OF CALCULATION METHODS IN XENON/CT CBF: ANALYTICAL VS. NUMERICAL. Z Zhang. Diversified Diagnostic Products, Inc., Houston, Texas, USA

CBF calculation can be performed by either numerical or analytical solution of the Kety equation based, respectively, on measured or fitted air curve values. A comparison of these two methods was made, using patient data (n=30) and computer simulations. Although calculated CBF values were highly correlated, the numerical method was superior to the analytical in yielding less error of the fitted tissue curves, and being more adaptable Io variations in the measuring protocol.