Toshiaki Kodera

Experimental and clinical study of detection of glioma at surgery using fluorescent imaging by a surgical microscope after fluorescein administration.

Total resection is the optimal treatment for malignant gliomas. However, an unexpected residual tumor mass is sometimes found on magnetic resonance imaging performed after an operation because of a macroscopically unclear margin of the tumor at surgery. This study was designed to evaluate the effectiveness of fluorescent imaging by a surgical microscope after fluorescein administration for the detection of gliomas at surgery. For this study, we produced two filters for the excitation and emission of fluorescein that can be easily fitted to and removed from a surgical microscope manually during the operation. For the experimental study, Wistar rat brains bearing C6 glioma were removed at appropriate intervals after intravenous administration of 10-20 mg kg-1 body weight of sodium fluorescein, and their surface and coronal section through the tumor were observed using a surgical microscope with the filters. In clinical cases, 1000 mg of sodium fluorescein was intravenously administered to five patients with glioma before tumor resection. In the experimental study, the C6 glioma itself and the edematous brain adjacent to the tumor (within 2-3 mm of the gross surface of the tumor) were well stained a brilliant yellowish green for a few hours. The normal brain was not stained. In clinical cases, the tumors were stained a brilliant yellowish green under fluorescent observation at surgery. The patients had no side effects. At all times the fluorescent observation could be quickly changed to ordinary observation by removing the filters from the surgical microscope. The tumor was also stained a faint yellow under ordinary nonfluorescent observation. Although this contributed to detection of the tumor, the fluorescent staining demarcated the tumor more clearly than nonfluorescent staining. These results suggest that this imaging technique by a surgical microscope with special filters at surgery may be practical and useful for detection of gliomas and warrants further clinical evaluations.

Neurosurgical venous considerations for tumors of the pineal region resected using the infratentorial supracerebellar approach

The authors present a microsurgical technique for the resection of a heterogeneous group of pineal-region tumors and discuss the key points for successfully performing this surgery. Twenty-six consecutive patients with pineal-region tumors were resected by the senior author (H.B.) and analyzed retrospectively. For all 26 patients, the operation was conducted using the infratentorial supracerebellar (ITSC) approach in the sitting (23 patients) or Concorde (three patients) positions. Twenty-five patients had symptomatic obstructive hydrocephalus and were treated with ventricular drainage, a previously inserted ventriculoperitoneal shunt, or an endoscopic third ventriculostomy before undergoing resection of the pineal-region tumor. The gross total removal of the tumor was achieved in 23 patients and subtotal removal was achieved in three patients. The tumors were pathologically diagnosed mainly as pineocytomas (10), pilocytic astrocytomas (6), or pineal cysts (4). Twenty-five of the patients clinically improved after surgery, and there was no mortality. Two patients experienced transient postoperative neurological deterioration: one patient developed Parinaud syndrome, and one patient developed intermittent diplopia. Successful surgery and patient outcome when treating tumors of the pineal region using the ITSC approach requires: (i) preservation of the venous flow of the Galenic draining system; (ii) preservation of the thick bridging veins of the tentorial surface of the cerebellum, especially the hemispheric bridging veins; and (iii) minimizing retraction of the cerebellum during surgery to avoid adverse effects caused by both direct cerebellar compression and disturbance of the venous circulation.

MR imaging and CT of pituitary abscess: Case report and review

Pituitary abscess is a rare disorder. However, preoperative diagnosis is important to prevent a cranial approach leading to severe meningitis. A case of a 55 year-old woman with pituitary abcess is reported. The patient was admitted with a several-week history of frontal headache and no signs of inflammation. Computed tomographic (CT) scan showed a slightly low-density suprasellar expanding mass lesion with an enhanced thin wall in the pituitary region. Magnetic resonance imaging showed a homogenous high-intensity signal relative to brain parenchyma on T1-weighted images with an enhanced thin wall and a homogenous low-intensity signal on T2-weighted images. This was histologically shown to be a pituitary abscess. Our case and review of the available literature suggest that pituitary abscess generally shows a homogenous low-density on CT scan and a homogenous low- to iso- and high-intensity signals or homogenous high- and low-intensity signals on T1- and T2-weighted images, respectively, with a cystic appearance and enhanced smooth wall.

The Expression and Activation of Matrix Metalloproteinase-2 in Rat Brain After Implantation of C6 Rat Glioma Cells

It has been reported that matrix metalloproteinases (MMPs) are highly expressed in malignant glioma cells and that this increased expression may facilitate the invasiveness of tumor cells. The authors investigated the expression and enzymatic activity of MMPs in rat brain during the growth of malignant gliomas at different time intervals. C6 rat glioma cells were unilaterally implanted into rat cerebral hemispheres. After 7 or 14 days, these brain tissues were prepared for SDS-PAGE zymography, Western blotting, immunohistochemistry, and in situ zymography. SDS-PAGE zymography and Western blotting revealed that the expression of proMMP-2 in rat brains with C6 glioma cells was significantly higher than that in normal or the sham-operated rat brains, and that the activated form of MMP-2 was detected only in the former but not in the latter. On immunohistochemistry, C6 glioma cells presenting invasive growth into the rat brain parenchyma and vessels demonstrated MMP-2 immunoreactivity. On in situ zymography, foci of invasive C6 glioma cells in rat brain tissue showed gelatinolytic activity. These results suggest that expression and activation of MMP-2 may be one of the crucial steps for glioma cell invasion into the brain parenchyma in vivo.

Analysis of the proliferative potential of tumor cells after stereotactic radiosurgery for recurrent astrocytic tumors.

Abstract We analyzed the effectiveness of stereotactic radiosurgery (SRS) for recurrent astrocytic tumors histologically. Five patients were followed by pathological examination after radlosurglcal treatment of recurrent astrocytic tumors. Histological diagnoses at the time of the last operation before SRS were Daumas-Duport grade II in two patients and grade IV (glioblastoma) in three patients. No histological diagnoses at the time of SRS were identified in any patients. Contrast enhanced lesions enlarged gradually on magnetic resonance (MR) images after SRS, and local control by SRS was judged as progressive disease radiologically in all patients. Four of five patients received re-operation after SRS, and the other patient died without re-operation and underwent post-mortem examination. After SRS, Ki-67 labeling indices (Lis) of recurrent astrocytomas initially diagnosed as grade II were 2.6% and 1.1%. These Us were relatively lower than those of the control group of patients with recurrent grade II astrocytomas that were not treated by SRS. Ki-67 Us of three glioblastomas after SRS were 23.5%, 18.6%, and 17.8%. These Us were significantly lower than those before SRS (2.3%, 4.5%, and 0.9%). In the autopsy case, there was a significant difference between the LI of tumor cells in the radiosurgically treated region (0.9%) and that in the untreated region (29.2%). These results suggest that the proliferative potential of malignant astrocytic tumors in the radiosurgically treated area is reduced after SRS, and that radiological enlargement of enhanced lesions on MR images is due to propagation of the residual tumor cells that were not covered by radlosurgical target volume or to radiation necrosis. SRS may be a useful therapeutic tool in multidisciplinary treatment of malignant gliomas. [Neurol Res 2000; 22: 802-808]

Arterial spin labeling perfusion-weighted MRI for long-term follow-up of a cerebral arteriovenous malformation after stereotactic radiosurgery

We present a longitudinal series of arterial spin-labeling magnetic resonance imaging (ASL-MRI) in a patient with cerebral arteriovenous malformations (AVMs) treated by stereotactic radiosurgery (SRS). Pretreatment ASL-MRI showed high signal intensity in both the nidus and draining veins, and the latter signal abnormality gradually moved proximally by 14 months after SRS. At 24 months, the signal abnormalities finally disappeared, indicating complete obliteration of the nidus. The hemodynamic changes in the AVM were clearly visualized in the longitudinal ASL-MRI series, thus this non-invasive MR method may be useful not only for detecting AVMs but also for assessment of their response after SRS.

Radiological findings for arterial dissection of the anterior cerebral artery

We treated a patient with anterior cerebral artery (ACA) dissection that caused an ischaemic stroke, and investigated serial changes over time by using three different radiological methods. The conventional angiography findings for ACA dissection corresponded to those of computed tomography (CT) angiography, but not those of magnetic resonance angiography for each phase. We presume that the results were based on the velocity of the blood flow in the pseudolumen of the dissected artery, and we believe that CT angiography is a useful and less invasive diagnostic tool for intracranial arterial dissection.

Percutaneous Glycerol Rhizotomy for Trigeminal Neuralgia Using a Single-Plane, Flat Panel Detector Angiography System: Technical Note

Percutaneous treatments for trigeminal neuralgia (TN) including glycerol rhizotomy (GR), radiofrequency thermocoagulation (RT), and balloon compression (BC) are effective for patients with medical comorbidities and risk factors of microvascular decompression (MVD). These procedures are usually performed under fluoroscopy. Surgeons advance the needle to the trigeminal plexus through the foramen ovale while observing landmarks of fluoroscopic images; however, it is sometimes difficult to appropriately place the needle tip in Meckel’s cave. We present the technical details of percutaneous GR using a single-plane, flat panel detector angiography system to check the needle positioning. When the needle tip may be located near the trigeminal cistern, three-dimensional (3-D) bone images are taken with cone-beam computed tomography (CT). These images clearly show the position of the needle tip in Meckel’s cave. If it is difficult to place it through the foramen ovale, surgeons perform cone beam CT to observe the actual position of the needle tip at the skull base. After confirming the positional relation between the needle tip and foramen ovale, surgeons can advance it in the precise direction. In 10 procedures, we could place the nerve-block needle in about 14.5 minutes on average without complications. We think that our method is simple and convenient for percutaneous treatments for TN, and it may be helpful for surgeons to perform such treatments.

Spontaneous spinal epidural hematoma in a patient with acquired Factor X deficiency secondary to systemic amyloid light-chain amyloidosis

Abstract Background Spontaneous spinal epidural hematoma (SSEH) is relatively rare. SSEH with anticoagulants including warfarin and rivaroxaban (Factor Xa inhibitor) have been reported; however, SSEH with Factor X deficiency has not been described yet. Methods Case report. Findings An 82-year-old woman with acquired Factor X deficiency complained of sudden onset of severe posterior neck pain. Magnetic resonance imaging demonstrated an epidural hematoma from C3 to T3 levels. Because she showed tetraparesis on the third hospital day, we performed surgery. Just before surgery, her prothrombin time-international normalized ratio was 2.49, which was immediately reversed by infusion of prothrombin complex concentrate. The patient safely underwent an emergency laminectomy from C3 to T2, in which the epidural hematoma was evacuated. Post-operatively, the patient recovered completely without rebleeding. Hematologists found acquired deficiency of Factor X in this patient with systemic amyloid light-chain amyloidosis. Conclusion To our knowledge, this is the first report of a case of SSEH with Factor X deficiency. A blood coagulation disorder should be considered in patients with SSEH.

Expression of Matrix Metalloproteinases in the Chronic Subdural Haematoma Membrane

Summary¶ To study the role of matrix metalloproteinases (MMP) in the development of chronic subdural haematoma, we investigated the expression and activity of MMPs (MMP-1, -2, -3, -7 and -9) and tissue inhibitors of MMP (TIMP-1 and -2) in capsules of chronic subdural haematoma from 10 patients. Outer membranes of chronic subdural haematoma were immunostained for MMP-1, MMP-2, MMP-9, TIMP-1 and TIMP-2. Moreover, we confirmed MMP activity in membranes by SDS-PAGE zymography and in situ zymography. These results suggest that MMP degrades extracellular matrix in outer membranes of chronic subdural haematoma, which is thought to decrease their integrity followed by direct haemorrhage and exudation of oedematous fluid from membrane vessels into the haematoma cavity.