Yoshimi Matsuoka

Determining the appropriate stimulus intensity for studying the dipole moment in somatosensory evoked fields: a preliminary study

OBJECTIVE To establish a simple method of determining the appropriate stimulus intensity for studying the dipole moment in somatosensory evoked fields. METHODS In 17 patients (20 hemispheres), the authors studied the relationship between the dipole moment and stimulus intensity, which was quantified using the threshold of thenar muscle twitch (TMT). The dipole moment was measured at 1.0, 1.5 and 2.0 TMT. Two measurements were obtained at 1.5 TMT to determine the procedures margin of error. RESULTS There was no significant difference between the dipole moments measured at 1.5 and 2.0 TMT. CONCLUSIONS Setting the stimulus intensity at 1.5 TMT or more ensures a consistent response.

Direct surgical treatment of intracavernous internal carotid artery aneurysms: Report of four cases

The authors have operated directly on four cases of intracavernous internal carotid artery aneurysms by opening the cavernous sinus. Surgery was performed using a semisitting position, in which the upper half of the patients body was elevated approximately 20 degrees from the horizontal plane. The superior wall of the cavernous sinus was opened through the pterional approach, and an aneurysmal neck clipping was successfully performed on three patients. A coating of the aneurysm was carried out on one patient. The results obtained were excellent in all cases. The authors believe that the operative technique reported is useful for surgical treatment of intracavernous lesions.

Magnetic resonance imaging of infiltrating angiolipoma of the neck

Although infiltrating angiolipomas are histologically benign, recurrence has been reported in more than 50% of patients after partial extirpation. The authors have treated a 14-year-old female with a large infiltrating angiolipoma of the neck, in whom magnetic resonance imaging was more valuable than x-ray computed tomography and angiography in delineating the extent of the tumor. Total removal of the tumor was performed with the aid of an operating microscope. To our knowledge, this is the first description of the magnetic resonance imaging of an infiltrating angiolipoma. When other neuroradiologic examinations cannot be considered to demonstrate the extent of the tumor accurately, magnetic resonance imaging may be recommended.