Jun-ichi Nakamura

Gamma knife surgery for Cushing's disease

BACKGROUND The efficacy of gamma knife surgery on Cushings disease is not well known to date. In most reported cases of Cushings disease treated with gamma knife, the area to be irradiated was determined with computed tomography or pneumoencephalography. We report two cases of recurrent pituitary-dependent Cushings disease treated with gamma knife using stereotactic magnetic resonance imaging (MRI). MATERIALS AND METHODS Recurrent microadenomas were visualized as hypointense areas using gadolinium-enhanced MRI after two transsphenoidal surgeries in both cases. The doses of irradiation given were 35 Gy and 20 Gy to the margin of the tumors, and less than 8 Gy and 21 Gy to the optic apparatus and cranial nerves in the cavernous sinus, respectively. RESULTS Both patients had clinical remission with normal serum cortisol and adrenocorticotrophic hormone levels, during 2-year follow-up after radiosurgery, without endocrinologic deficiency or neurologic deterioration. CONCLUSIONS Gamma knife surgery can be an alternative therapy for Cushings disease when pituitary adenomas are apart from the optic apparatus and can be visualized clearly by MRI, even if tumors are recurrent after microsurgery.

Quantification of regional cerebral blood flow and vascular reserve in childhood Moyamoya disease using [123I]IMP-ARG method

Both regional cerebral blood flow (rCBF) and regional vascular reserve (rVR) in ten childhood Moyamoya disease were quantified pre- and post-operatively by autoradiographic processing using single photon emission computed tomography (SPECT) and N-isopropyl-rho-iodoamphetamine (IMP) (IMP-ARG method) to estimate hemodynamic effectiveness of surgical revascularization. Before surgery, in two patients, rCBF was reduced in the whole territories and loss of rVR in the anterior circulation was observed; +4.3% in the anterior cerebral artery (ACA), -3.0% in the middle cerebral artery (MCA) and +17.5% in posterior cerebral artery (PCA) territories. After surgery, in eight patients without transient ischemic attack (TIA) episodes, rCBF at rest was maintained around subnormal level in the whole territories, and mean rVR was up to +11.9, +17.3 and +28.3% in ACA, MCA and PCA territories, respectively. However, rVR in the anterior circulation was significantly reduced in comparison with rVR in the posterior circulation. Quantification of both resting rCBF and rVR using IMP-ARG method could provide reliable information concerning on surgical indication and its effectiveness in childhood Moyamoya disease.

Transient ischemic attacks caused by unruptured intracranial aneurysm

A case is reported of a 56-year-old man in whom an unruptured aneurysm of the left middle cerebral artery was the source of emboli resulting in transient ischemic attacks (TIAs). The potential relationship between TIAs and an unruptured aneurysm is discussed, and the literature is reviewed.

Completely thrombosed giant aneurysm of the angular artery

An unusual case of a completely thrombosed giant aneurysm arising from the angular artery is reported. A 69-year-old women developed a subarachnoid hemorrhage with a large intracranial hematoma. Computed tomography scans and cerebral angiography could not detect the aneurysm. The rarity of aneurysms in this position is stressed and the difficulty of diagnosis in this case is discussed.

Effect of gamma knife irradiation on relaxation and contraction responses of the common carotid artery in the rat

SummaryThis report concerns a pilot study of the short- and long-term effects of gamma knife radiosurgery on vascular responses. The investigation was carried out on male Sprague-Dawley rats, and the relaxation and contraction responses of the right common carotid artery (CCA) were assessed following irradiation (100 Gy). The non-treated CCA of the same animals served as internal controls. Non-irradiated rats were used to control the effect of normal aging on vascular function. Isometric tension was determined on in vitro preparations of arterial rings. Acetylcholine-mediated, endothelium-dependent relaxation was impaired one month after radiosurgery, as was endothelium-independent relaxation induced by sodium nitroprusside, but the effect on the latter was minimal. The irradiated CCA was also impaired with respect to contraction responses induced by norepinephrine, endothelin-1 or phorbol dibutyrate. This impairment appeared to be biphasic, as it was evident one day after radiosurgery, followed by a partial recovery one week later, and again manifest after one month. At the light microscope level, the carotid arteries appeared to be well preserved throughout the experiment. However, obvious ultrastructural changes were noted in endothelial and smooth muscle cells of specimens obtained three months after radiosurgery. The present data indicate that high dose gamma knife radiosurgery affects the functions of both, the vascular endothelium and the vascular smooth muscles in an apparent time-dependent fashion. Because of its increasing application to patients, there is the need for studying the effects of gamma knife radiosurgery on cerebral arteries, since functional vascular changes may occur in the absence of obvious histological alterations. Our results on CCAs point to the feasibility of such experimental investigations.

Surgical results of intracranial ruptured aneurysms in the acute stage

SummaryTo evaluate the operative mortality and morbidity of definitive intracranial microsurgical aneurysm obliteration as a function of timing of early operative intervention and as a function of clinical condition at the acute stage, we retrospectively review 164 consecutive patients who underwent surgery within 72 hours following haemorrhage. The series was divided into four operation periods (0–6, 6–12, 12–24, 24–72 hours), and patients were graded according to five clinical conditions described by Hunt and Hess. The mortality of the individual clinical condition at each operation period was to great extent independent of the timing of operation, and there was a distinct correlation between the surgical results and the form of bleeding visualized by C. T. In poor condition (grade 3, 4, and 5) patients, satisfactory surgical results were obtained in patients in whom cisternal blood clots, intracerebral haematoma, and subdural haematoma had been shown by C.T. The optimum operation times for each group were suggested.

Correlation of SPECT with Angiography in Early Ischemic Stroke

The hyperacute thrombolytic therapy for selected patients with embolic stroke may actually provide benefit rather than risk [1–9]. The patient selection in thrombolytic stroke therapy might depend on early diagnosis of severity of cerebral ischemia or reversibility in ischemic brain tissue. It has been known that not only the time from the onset of stroke but also the residual cerebral blood flow (CBF) appear to be crucial for survival of marginal hypoperfusion areas [10–12]. A critical level of residual CBF might indicate functional reversibility in ischemic brain tissues and could be restored by early efficient recanalization of the occluded vessels. Cerebral angiographic studies in the early phase of embolic stroke could show prompt development of collateral circulating, reflecting residual CBF, and the degree of reperfusion following thrombolytic therapy in relation to increased CBF. To investigate the role of cerebral angiography in acute embolic stroke, we studied the correlation of CBF using single photon emission computed tomography (SPECT) with angiographic findings in early ischemic stroke within 6 h from the stroke onset.