Neurologia medico-chirurgica

Original Articles

Brain Hypothermia Relieves Severe Brain Swelling Following Acute Major Cerebral Artery Occlusion

Yasutaka KUROKAWA, Hitoshi KANO, Yasuyuki YONEMASU, Takahiro SASAKI, K ...

2001 Volume 41 Issue 2 Pages 53-62
Published: 2001
Released on J-STAGE: July 03, 2005

DOIhttps://doi.org/10.2176/nmc.41.53

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Seven patients were treated with brain hypothermia following acute major cerebral artery occlusion to utilize the suppressive effect against brain swelling. Five patients had internal carotid and two had proximal middle cerebral artery occlusion. Except for the first two cases, hypothermia was introduced early and the temperature reached 35.0°C within 6 hours after the onset. The core temperature finally stabilized between 32°C to 34°C. Hypothermia had a suppressive effect against brain swelling and the temperature showed a significant correlation to intracranial pressure. Recurrence of brain swelling was observed during the rewarming process, but two patients became independent and three patients were moderately disabled in wheelchairs. Only two patients died. Brain hypothermia is an effective treatment for acute major cerebral artery occlusion through the relief of brain swelling. The overall outcome may be improved by combining brain hypothermia with other conventional therapies such as osmotherapy and external decompression implemented with an extended period of rewarming.

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Time Course of Expression of Three Nitric Oxide Synthase Isoforms After Transient Middle Cerebral Artery Occlusion in Rats

Masahiro NIWA, Suguru INAO, Masakazu TAKAYASU, Tatsumi KAWAI, Yasukazu ...

2001 Volume 41 Issue 2 Pages 63-73
Published: 2001
Released on J-STAGE: July 03, 2005

DOIhttps://doi.org/10.2176/nmc.41.63

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The involvement of nitric oxide synthase (NOS) in ischemia was evaluated by detecting the expression of neuronal NOS (nNOS), endothelial NOS (eNOS), and inducible NOS (iNOS) by the immunohistochemical method in the rat model of middle cerebral artery (MCA) occlusion. Transient MCA occlusion (2 hours) was induced in 32 male Wistar rats by extracranial insertion of a 3-0 nylon thread through the internal carotid artery into the MCA. Animals were killed at 0, 6, 24, 72, and 168 hours after MCA occlusion (n = 6, 6, 8, 6, and 6, respectively). The brains were fixed with periodate-lysine-paraformaldehyde, frozen, and sectioned. Sections were stained with polyclonal antibody against nNOS, eNOS, and iNOS. Each section was evaluated by microscopic observation (×100). The number of nNOS-positive neurons was 41.6 ± 5.8 (mean ± SD) in the control hemisphere. nNOS was upregulated in the ischemic hemisphere (88.3 ± 18.9), especially in the border zone at 6 hours after MCA occlusion. However, the number decreased to 36.4 ± 3.6 and 26.3 ± 7.3 in the ischemic hemisphere after 72 and 168 hours, respectively. eNOS immunoreactivity was present in the endothelium of major vessels at each time point. eNOS was not detected in the microvessels before ischemia, but faint staining was found in the endothelium at 6 hours after MCA occlusion. Immunostaining became more intense thereafter. Faint iNOS immunoreactivity was seen in the microvessels at 6 hours after MCA occlusion. Macrophages in the ischemic core and astrocytes in the border zone showed immunoreactivity to iNOS at 72 and 168 hours after MCA occlusion. Three types of NOS must be related to different stages of ischemic brain damage. nNOS may be neurotoxic in ischemia in the early phase, like iNOS in the late phase. On the other hand, eNOS seemed to be neuroprotective in all stages. These observations suggest the necessity for tailored therapeutic intervention against NOS isoforms at each stage in patients with ischemic stroke.

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Improvement of Phase-Contrast Flow Measurements: Opposite Directional Flow-Encoding Technique to Eliminate the Influence of the Maxwell Term Phase Errors

Osamu YUKAWA

2001 Volume 41 Issue 2 Pages 74-82
Published: 2001
Released on J-STAGE: July 03, 2005

DOIhttps://doi.org/10.2176/nmc.41.74

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A new method termed the opposite directional flow-encoding (ODFE) technique is proposed to increase the accuracy and the reproducibility of phase-contrast flow measurements by correcting the non-linear background of velocity images induced by concomitant magnetic fields (Maxwell terms). In this technique, the volume flow rate is calculated from the difference of two region of interest (ROI) values derived from two velocity images obtained by reversing the flow-encoding direction. To evaluate the technique, various phantom experiments were carried out and volume blood flow rates of internal carotid arteries (ICAs) were measured in four volunteers. The technique could measure the volume flow rates of the phantom with higher accuracy (mean absolute percentage error = 1.04%) and reproducibility (coefficient of variation = 1.18%) than conventional methods. Flow measurements with the technique was not significantly affected by ROI size variation, measuring position, and flow obliquity not exceeding 30°. The volume flow rates in the ICAs of a volunteer were measured with high reproducibility (coefficient of variation = 2.89% on the right, 1.48% on the left), and the flow measurement was not significantly affected by ROI size variation. The ODFE technique can minimize the effect of the non-linear background due to Maxwell terms. The technique allows use of ROIs of approximate size including the flow signal and provides accurate and objective phase-contrast flow measurements.

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Case Reports

Growth of Occult Arteriovenous Malformation After Cerebral Hemorrhage Demonstrated by Serial Magnetic Resonance Imaging

—Case Report—

Takahisa FUSE, Yuji NIWA, Masanari UMEZU, Kazuo YAMADA

2001 Volume 41 Issue 2 Pages 83-86
Published: 2001
Released on J-STAGE: July 03, 2005

DOIhttps://doi.org/10.2176/nmc.41.83

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A 19-year-old male presented with sudden onset of right hemiparesis caused by left cerebral hemorrhage. Cerebral angiography demonstrated no vascular abnormality, and the hematoma was removed surgically. At operation, no abnormal vascular lesion was found in the brain adjoining the hematoma. Two years later, magnetic resonance (MR) imaging demonstrated a few foci of flow voids adjacent to the hematoma cavity. Four years after the hemorrhage, MR imaging showed more extensive flow-void abnormalities that indicated growth of an occult arteriovenous malformation (AVM). Cerebral angiography indicated a definite AVM supplied mainly by branches of the middle cerebral artery. Total resection of this lesion was performed. The histological diagnosis was typical AVM. Immunohistochemistry with vascular endothelial growth factor showed staining in the walls of the abnormal vessels. Serial MR imaging is very useful for the diagnosis and management of occult AVMs.

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Hemifacial Spasm Due to Cerebellopontine Angle Meningiomas

—Two Case Reports—

Yoshiyasu IWAI, Kazuhiro YAMANAKA, Hideki NAKAJIMA

2001 Volume 41 Issue 2 Pages 87-89
Published: 2001
Released on J-STAGE: July 03, 2005

DOIhttps://doi.org/10.2176/nmc.41.87

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A 54-year-old female and a 49-year-old female presented with complaints of hemifacial spasm. Both patients underwent surgery to remove cerebellopontine angle meningiomas. In one case, no vascular compression was observed at the root exit zone. The tumor was removed subtotally leaving residual tumor adhered to the lower cranial nerves. The hemifacial spasm disappeared immediately after the operation. The residual tumor was treated using gamma knife radiosurgery. In the other case, the root exit zone of the facial nerve was compressed by both the tumor and anterior inferior cerebellar artery and the tumor was removed totally. Postoperatively, the hemifacial spasm disappeared, but the patient suffered facial nerve paresis and deafness that was probably due to intraoperative manipulation. However, the facial nerve paresis gradually improved. Cerebellopontine angle meningioma with hemifacial spasm must be treated by surgical resection limited to preserve cranial nerve function. Subtotal removal with subsequent radiosurgery to treat the remaining tumor tissue is one option for the treatment of cerebellopontine angle meningioma.

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Intracranial Meningeal Malignant Fibrous Histiocytoma Mimicking Parasagittal Meningioma

—Case Report—

Masanori TSUTSUMI, Teruaki KAWANO, Tsutomu KAWAGUCHI, Yoshirou KANEKO, ...

2001 Volume 41 Issue 2 Pages 90-93
Published: 2001
Released on J-STAGE: July 03, 2005

DOIhttps://doi.org/10.2176/nmc.41.90

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A 69-year-old female presented with a rare intracranial meningeal malignant fibrous histiocytoma (MFH). The neuroimaging appearance of this tumor was very similar to parasagittal meningioma. The tumor was grossly totally removed, and local irradiation of 50 Gy was performed. The histological diagnosis was MFH. The patient recovered from the preoperative deficits, and no recurrence was observed by 27 months after surgery.

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Midline Posterior Fossa Teratoma

—Case Report—

Ketan DESAI, Trimurti NADKARNI, Dattatraya MUZUMDAR, Atul GOEL

2001 Volume 41 Issue 2 Pages 94-96
Published: 2001
Released on J-STAGE: July 03, 2005

DOIhttps://doi.org/10.2176/nmc.41.94

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A 20-day-old female neonate presented with an immature teratoma in the midline posterior fossa. The tumor was totally removed but the patient died of pneumonia. Teratoma is a rare tumor, but very difficult to treat as the patients tend to be young, and the outcome is very poor.

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Migration of a Lumboperitoneal Shunt Catheter into the Spinal Canal

—Case Report—

Takeshi SATOW, Yasushi MOTOYAMA, Naohiro YAMAZOE, Fumiaki ISAKA, Kazus ...

2001 Volume 41 Issue 2 Pages 97-99
Published: 2001
Released on J-STAGE: July 03, 2005

DOIhttps://doi.org/10.2176/nmc.41.97

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A 50-year-old female suffered upward migration of a lumboperitoneal (LP) shunt catheter into the spinal canal, manifesting as disturbance of short-term memory. Revision of the shunt confirmed that the tube had migrated into the spinal canal. The tube was pulled back into the peritoneal cavity and attached firmly to the fascia with a new anchoring device. LP shunts have the advantages of technical simplicity and extracranial procedure, but firm fixation is recommended since movements of the spine may cause proximal tube migration.

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In Vivo Histological Changes Occurring in Hydroxyapatite Cranial Reconstruction

—Case Report—

Norifumi OKII, Shigeru NISHIMURA, Kaoru KURISU, Yukio TAKESHIMA, Tohru ...

2001 Volume 41 Issue 2 Pages 100-104
Published: 2001
Released on J-STAGE: July 03, 2005

DOIhttps://doi.org/10.2176/nmc.41.100

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Histological changes were observed in a hydroxyapatite plate and hydroxyapatite granules used to repair a craniotomy defect and removed after 2 years and 9 months of use. The hydroxyapatite plates and granules had completely fused to the cranium, with new bone formation on the dural side extending in a three-dimensional matrix along the pores with the Haversian system in the center. New bone formation was less extensive under the artificial dura than under the normal dura. This finding suggests that the dura has the ability to promote bone formation. A new vessel was found along the interconnecting pores. The interconnecting pores allow osteoconduction in the hydroxyapatite plate, so new bone formation can progress. Hydroxyapatite has osteoconduction properties and is biocompatible, so gains strength in vivo through new bone formation, and is the ideal material for artificial bones. Factors important to achieving good bone formation after cranial reconstruction surgery include presence of the dura, and pore size approximate to the Haversian system (100-500 μm) and interconnecting pores in the hydroxyapatite plate.

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