S17. Experimental Study on

Mitsuo TsURU, Kenzoh YADA and Minoru TSUNODA Dept. of Neurosurgery, Hokkaido University School of Medicine

Using a physiological pressure transducer, prolonged supratentorial intra- cranial pressure was recorded in cats with experimentally produced intracerebral hematoms, together with recordings of electroencephalogram, arterial and venous pressure, pulse rate, respiration rate, and electrocardiogram. Except for these which die right after the introduction of intracerebral hematoma due to respiratory arrest, the intracranial pressure soon starts to de- cline and continues to decline until it reaches close to normal range. In this stage, although resting intracranial pressure is fairly close to normal, it can extremely easily be elevated by various factors such as minor change of respira- tion, straining etc. We offer to call this appearing normal, but very unstable state of intracranial condition as "latent intracranial hypertension". This im- portant finding gives us warning not to give unnecessary manipulations to the patients with intracranial hematomas even in case they do not seem to have extremely high intracranial pressure.

S18. Experimental Studies in : Echoencephalographic, Electroencephalographic and Histologic Observations

Hajime NAGAI,Kazumi SAKURAI,Masayuki HAYASHI,Kazuhiro FURUSE, Kazuhiko OKAMURA,A. SHINTANI,and T. KOBAYASHI 2nd Dept. of Surgery,School of Medicine,Nagoya University

Recent advances in neurosurgery for hypertensive intracerebral hemorrhage have made possible to improve patients suffering from cerebrovascular disease. It is difficult problem, however, to differentiate cerebral hemorrhage from cerebral softening in practice. The purpose of the present paper is to estimate differentiation in both diseases, using echoencephalography and electroencephalography in dogs with experimental- ly produced intracerebral hematoma and cerebral infarction. Experiments have been performed on 36 dogs. 1) Echoencephalogram a) Intracerebral hematoma - 143- Intracerebral hematoma was produced by infusion of an aliquot (2 cc) of clot into the capsula interna using stereotaxic apparatus in 18 dogs. After infusion of the clot, immediately, multiple and sharp echos were obtained cor- responding to the foci. Then, these echos gradually decreased and became to be simple and dull at the beginning of the 3rd postoperative day. Both gradual autolysis in the hematoma and round cell infiltrations in the surrounding tissue were histologically observed. It was, therefore, concluded that, as the boarder line of the hematoma become obscure, difference of the impedance in both tissues and thus the inten- sity of the hematoma echos were decreased. b) Cerebral infarction Cerebral infarction was produced in 18 dogs by ligation of the middle cere- bral artery. No echos as characteristic to the infarcted region as the hematoma was recorded. Therefore, it was reasonable to conclude that the echoencephalography is a excellent procedure to differentiate the hematoma from the softening. 2) Electroencephalogram a) Intracerebral hematoma Serial investigations of electroencephalography of the dogs with intracerebral hematoma were performed in 31 postoperative days. Variable and inconstant findings in the involved side were obtained immedi- ately after the infusion, and then these pathological changes were gradually reduced up to approximately normal level. About one hour after the procedure, a few of slow waves appeared in the involved side and then increased gradually. On the 3rd to 7th postoperative day, in which period edema in the tissue sur- rounding the hematoma was most remarkable histologically, the slow waves be- came most dominant in the involved side and thereafter these changes were reduced day by day. b) Cerebral infarction Immediately after the ligation of the artery, flattening of the waves was observed in electroencephalogram. On the course of the experiment, slow waves that initially appeared were diminished gradually. Histological examination showed in the tissue surrounding the infarcted region that the nervous cells gradually regained the function and edema began to be reduced within 3 to 7 postoperative days. Serial electroencephalographic observations suggested the gradual restora- tion of the cerebral function immediately after the onset in the case of brain softening, and, on the other hand, the temporary deterioration for 3 to 7 post- operative days, followed by progressive improvement in the cases with intra- cerebral hematoma. Conclusively, the findings which seems to be characteristic to the softening or the hemorrhage can not be obtained by the electroencephalogram recorded -144- only one time after the .

Therefore, the follow-up data that differs from each other through the course, above mentioned, may suggest the possibility of differential diagnosis of the both diseases.

S19. Ultrasonic Diagnosis of Apoplexy

Sadanori KIKUCHI, Kazufumi ITO, Yuichi ABE and Toshio WAGAI Dept. of Surgery, Juntendo UniversitySchool of Medicine

As already reported, the present writers have succeeded since 1952 in dia- gnosing brain tumors mainly employing A-scope indication method. It is very important to differentiate accurately the cerebral hemorrhage from other condition such as stroke, not only for the purpose of an ordinary treatment but also for the surgical treatment of this disease. In this paper the ultrasonic diagnosis of apoplexy will be presented. Through the experiment of the formalin-hardend brain slice of apoplexy, the echoes from the hematoma are obtained by using brain slice with cerebral hematoma; however, no special echoes are observed in the case of brain softening and subarachnoid hemorrhage. The present writers then confirmed experimental- ly that artificial cerebral hematoma made by injection of blood coagula into a cat brain can be detected by using 5 megacycle ultrasound together with the finding of simultaneous shift of midline echo. In clinical cases of intracerebral hemorrhage, echoes reflected from hematoma are generally detected together with the displacement of third ventricle echo. The echoes of hematoma show a characteristic pattern, irregularly grouped but continuous pulsive echoes. On the contrary, in the cases of subarachnoid hemor- rhage and-brain softening, remarkable echo is never observed. Ultrasonic examination is very suitable for the quick diagnosis of these cases especially in acute cases.

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