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Masahito Fujimoto, Eiji Yoshino, Norihiko Mizukawa and Kimiyoshi Hirakawa

✓ The authors describe the case of a pregnant woman with a large prolactin-producing pituitary adenoma that regressed after delivery. The patient's neurological signs and symptoms spontaneously disappeared soon after delivery without treatment. Reduction in tumor size was confirmed on computerized tomography scans. It is hypothesized that the growth rate of a prolactinoma may be accelerated by estrogen.

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Satoshi Okada, Yoshio Nakagawa and Kimiyoshi Hirakawa

✓ A 10-year-old girl was admitted to the hospital with complaints of progressive right hemiparesis and sensory disturbance. Magnetic resonance imaging revealed a Chiari Type I malformation and syringomyelia from T-10 to C-1. The syrinx extended from the medulla to the right putamen along the pyramidal tract.

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Eiji Yoshino, Tarumi Yamaki, Toshihiro Higuchi, Yoshiharu Horikawa and Kimiyoshi Hirakawa

✓ Dynamic computerized tomography (CT) was performed on 42 patients with acute head injury to evaluate the hemodynamics and to elucidate the nature of fatal diffuse brain bulk enlargement. Patients were divided into two groups according to the outcome: Group A included 17 nonfatally injured patients, eight with acute epidural hematomas and nine with acute subdural hematomas; Group B included 25 fatally injured patients, 16 with acute subdural hematomas and nine with bilateral brain bulk enlargement. Remarkable brain bulk enlargement could be seen in all fatally injured patients with acute subdural hematoma. In 29 (69%) of 42 patients, dynamic CT was performed within 2 hours after the impact.

In the nonfatally injured patients with brain bulk enlargement, dynamic CT scans suggested a hyperemic state. On the other hand, in 17 (68%) of the 25 fatally injured patients, dynamic CT scans revealed a severely ischemic state. In the fatally injured patients with acute subdural hematoma, CT Hounsfield numbers in the enlarged hemisphere (hematoma side) were significantly lower than those of the opposite side (p < 0.001). Severe diffuse brain damage confirmed by follow-up CT scans and uncontrollable high intracranial pressure were noted in the fatally injured patients. Brain bulk enlargement following head injury originates from acute brain edema and an increase of cerebral blood volume. In cases of fatal head injury, acute brain edema is the more common cause of brain bulk enlargement and occurs more rapidly than is usually thought.

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Takanori Fukushima, Buichi Ishijima, Kimiyoshi Hirakawa, Norio Nakamura and Keiji Sano

✓ The authors report a new ventriculofiberscope useful in both diagnosing and operating on lesions of the ventricular system. The technique and its advantages are illustrated in representative cases.

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Masahito Fujimoto, Eiji Yoshino, Tadashi Ueguchi, Norihiko Mizukawa and Kimiyoshi Hirakawa

✓ Two cases of pituitary apoplexy are presented. A fluid blood density level was demonstrated by computerized tomography in a suprasellar ring-enhancing lesion.

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Shoji Naruse, Yoshiharu Horikawa, Chuzo Tanaka, Kimiyoshi Hirakawa, Hiroyasu Nishikawa and Kazuo Yoshizaki

✓ The water in normal and edematous brain tissues of rats was studied by the pulse nuclear magnetic resonance (NMR) technique, measuring the longitudinal relaxation time (T1) and the transverse relaxation time (T2). In the normal brain, T1 and T2 were single components, both shorter than in pure water. Prolongation and separation of T2 into two components, one fast and one slow, were the characteristic findings in brain edema induced by both cold injury and triethyl tin (TET), although some differences between the two types of edema existed in the content of the lesion and in the degree of changes in T1 and T2 values. Quantitative analysis of T1 and T2 values in their time course relating to water content demonstrated that prolongation of T1 referred to the volume of increased water in tissues examined, and that the two phases of T2 reflected the distribution and the content of the edema fluid. From the analysis of the slow component of T2 versus water content during edema formation, it was demonstrated that the increase in edema fluid was steady, and its content was constant during formation of TET-induced edema. On the contrary, during the formation of cold-injury edema, water-rich edema fluid increased during the initial few hours, and protein-rich edema fluid increased thereafter. It was concluded that proton NMR relaxation time measurements may provide new understanding in the field of brain edema research.

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Tomokatsu Hori, Kimiyoshi Hirakawa, Buichi Ishijima, Shinya Manaka, Takanori Fukushima, Natsue Shimizu and Tsunemasa Sato

✓ The successful surgical treatment of an intrameatal aneurysm is reported, and the signs, symptoms, and neurootological findings discussed. Anatomical consideration of the course of the anterior inferior cerebellar artery and origin of internal auditory artery are emphasized.

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Ryuta Suzuki, Hiroyuki Masaoka, Yukio Hirata, Fumiaki Marumo, Eiji Isotani and Kimiyoshi Hirakawa

✓ Plasma and cerebrospinal fluid (CSF) endothelin (ET)-1-like immunoactivity in 27 patients with aneurysmal subarachnoid hemorrhage (SAH) was measured serially by radioimmunoassay for 2 weeks after SAH onset. Mean ET-1-like immunoactivity levels in plasma of patients with SAH were highly elevated during the whole study period, while the levels in CSF of the same patients were not. Plasma ET-1-like immunoactivity levels in patients with SAH classified as Fisher computerized tomography (CT) Group 3 were higher than those in patients with SAH classified as Fisher CT Groups 1 and 2. There were no significant differences in plasma ET-1-like immunoactivity levels between the patient groups stratified by Hunt and Kosnik grade. In this series, plasma ET-1-like immunoactivity levels in the 12 patients with vasospasm were higher than those in the 15 patients without vasospasm during the 1st week; CSF ET-1-like immunoactivity levels in patients with vasospasm were in the normal range on Days 0 to 3 after SAH onset, then became elevated on Days 5 to 7 and remained high until the end of the 2nd week. In contrast, CSF ET-1-like immunoactivity levels in patients without vasospasm were within the normal range during the entire period of study. The time course of the occurrence of vasospasm and that of the increase in CSF ET-1-like immunoactivity coincided precisely. The possible role of endogenous ET-1 in the pathogenesis of vasospasm due to SAH is discussed.

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Toshihiko Kuroiwa, Tsukasa Nagaoka, Masato Ueki, Ichiro Yamada, Naoyuki Miyasaka, Hideaki Akimoto, Shizuko Ichinose, Riki Okeda and Kimiyoshi Hirakawa

Object. The authors examined the correlation between changes in the apparent diffusion coefficient, regional water content, and tissue ultrastructure after vasogenic brain edema.

Methods. Vasogenic edema was induced in the white matter of six cats by cortical cold lesioning. The trace of diffusion tensor (Trace[D]) obtained from magnetic resonance imaging to measure the orientationally averaged water diffusibility was compared with the corresponding tissue water content determined by gravimetric studies and with ultrastructural water localization. Edema fluid had spread to the subcortical and deep white matter by 4.5 hours postlesioning. The increase in Trace(D) showed a significant linear correlation with the increase in tissue water content, both in the subcortical and deep white matter as follows: y = 45.5x − 2367 (r = 0.94) and y = 37.0x − 1769 (r = 0.93), respectively, where x is the water content (gram water/gram tissue) and y the Trace(D) (× 10−6 mm2/second). On histological examination, nerve fibers were found to be dissociated in the white matter and the extracellular space was markedly enlarged with protein-rich fluid. No noticeable hydropic swelling of the cellular components was observed.

Conclusions. A linear correlation was observed between increases in Trace(D) and increases in extracellular water volume in in vivo vasogenic brain edema. A similar correlation between the subcortical and deep white matter showing different arrangements of nerve fibers (parallel compared with intermingled, respectively) indicated that measurement of Trace(D) is a suitable parameter for the evaluation of vasogenic brain edema.

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Tadashi Nariai, Katsushige Sato, Kimiyoshi Hirakawa, Yoshihisa Ohta, Yoji Tanaka, Kiichi Ishiwata, Kenji Ishii, Kohtaro Kamino and Kikuo Ohno

Object

Intrinsic optical signals in response to somatosensory stimuli were intraoperatively recorded during brain tumor surgery. In the present study, the authors report on the use of this technique as an intraoperative guide for the safe resection of tumors adjacent to or within the sensorimotor cortex.

Methods

In 14 patients with tumors adjacent to or within the sensorimotor cortex, intrinsic optical signals in response to somatosensory stimuli were recorded by illuminating the brain surface with Xe white light and imaging the reflected light passing through a bandpass filter (605 nm). Results were compared with intraoperative recordings of sensory evoked potentials in all 14 patients and with noninvasive mapping modalities such as magnetoencephalography and positron emission tomography in selected patients. In all but two patients, the somatosensory optical signals were recorded on the primary sensory cortex. Optical signals elicited by stimulation of the first and fifth digits and the three branches of the trigeminal nerve were recorded at different locations on the sensory strip. This somatotopic information was useful in determining the resection border in patients with glioma located in the sensorimotor cortex.

Conclusions

Optical imaging of intrinsic signals is a useful technique with superior spatial resolution for delineating the somatotopic representation of human primary sensory cortex. Furthermore, it can be used as an intraoperative monitoring tool to improve the safety and accuracy of resections of brain tumors adjacent to or within the sensorimotor cortex.