Hirotsugu Samejima

Voxel-based morphometry to discriminate early Alzheimer's disease from controls.

We assessed the accuracy of voxel-based morphometry (VBM) using a three-dimensional T1-weighted MRI in discriminating Alzheimers disease (AD) in the very early stage of amnestic type of mild cognitive impairment and age-matched healthy controls. We randomly divided these subjects into two groups. The first group comprising 30 AD patients and 41 controls was used to identify the area with the most significant gray matter loss in patients compared to normal controls based on the voxel-based analysis of a group comparison. The second group comprising 31 patients and 41 controls was used to determine the discrimination accuracy of VBM. A Z-score map for a gray matter image of a subject was obtained by comparison with mean and standard deviation gray matter images of the controls for each voxel after anatomical standardization and voxel normalization to global mean using the following equation; Z-score=([control mean]-[individual value])/(control S.D.). Receiver operating characteristic curves for a Z-score in the bilateral medial temporal areas including the entorhinal cortex with the most significant loss in the first group showed a high discrimination accuracy of 87.8%. This result would open up a possibility for early diagnosis of AD using VBM.

Occlusion of the deep cerebral veins

There are very few reports on occlusion of the deep cerebral veins in the adult, and none where cerebroangiography was used. We report here a case of occlusion in the Galen and straight sinuses.

Demonstration of focal brain ischemia induced by hyperventilation using Tc-99m HMPAO SPECT

A case with vasospasm of the right anterior cerebral artery induced by hyperventilation is presented. Consecutive Tc-99m HMPAO brain SPECT studies at rest and during hyperventilation greatly contributed to the quantitative evaluation of focal perfusion decrease in conjunction with contrast angiography. This technique seems to be useful for the detection of alterations in regional brain perfusion during short duration intervention.

The Contact Nd:YAG Laser in Neurosurgery

It took 10 years to recognize the laser for its neurosurgical application since Rosomoff1 tried to use a ruby laser for surgery on a brain tumor. Today three lasers, CO2, argon and Nd:YAG, are widely used for neurosurgery. Among these lasers, the Nd:YAG has been evaluated to be inappropriate for neurosurgery, in spite of its excellent hemostatic capability, because of an unsatisfactory cutting-off effect. At the same time, this ability to achieve hemostasis has been highly successful in endoscopic procedures.

Automated voxel-based analysis of brain perfusion SPECT for vasospasm after subarachnoid haemorrhage

Background We evaluated regional cerebral blood flow (rCBF) during vasospasm after subarachnoid haemorrhage (SAH) using automated voxel-based analysis of brain perfusion single-photon emission computed tomography (SPECT).

35th Annual Meeting of the Japanese Society of Neuroradiology, 23–25 February 2006, Tokyo, Japan

35th Annual Meeting of the Japanese Society of Neuroradiology, 23–25 February 2006, Tokyo, Japan

Three-dimensional neuroimaging for brachytherapy of the brain

For brachytherapy of brain tumours, the exact location of the tumour and the relationship between the tumour and surrounding tissues and ventricles are very important. Three-dimensional neuroimaging using a volume-rendering method has been found very useful for this purpose. The number of introducers for isotope seeds can be determined and the length of seed which should be inserted into each introducer is also determined practically.