Sonodynamic therapy (SDT), a new approach to the treatment of cancer, is based on synergistic cell killing through a combination of sonosensitization and ultrasound, although the mechanism responsible for the effect remains to be elucidated. We have been interested in the emission of light due to acoustic cavitation induced by ultrasound irradiation, defined as sonoluminescence, and have been studying SDT for its potential application to secondary photodynamic therapy (PDT) . We carried out a quantitative study to determine the waveforms and peak wavelengths of luminescence in an aqueous solution subjected to ultrasonic excitation and also those of light obtained through ultrasound exposure by adding a photosensitizer to the solution. We then compared the resulting spectrograms with respect to the absorption wavelength and fluorescence wavelength of the drug. We confirmed that the fluorescence wavelength spectra obtained by ultrasound excitation of aqueous solutions of photosensitizers were formed due to absorption of some of the sonoluminescence and additional drug-specific fluorescence. We also found that the specific excitation spectrum of each photosensitizer was considerably decreased when DABCO, a singlet oxygen scavenger, was added to this experimental system.

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Using ultrasonography during medical checkups, we measured the flow velocity and diameter of vertebral arteries in 120 subjects, none of whom had obstruction in the vertebral arteries on MRA. Eleven of 240 arteries (4.6%) had a mean flow velocity lower than 18 cm/s. The flow in smaller arteries tended to be lower than that in larger ones.

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We performed transcranial Doppler sonography (TCD) in patients after subarachnoid hemorrhage (SAH) and observed the changes in mean flow velocity (MFV) in the bilateral middle cerebral arteries (MCA) .
Materials and methods: We examined MFV in both MCAs in 22 SAH patients using TCD (EME TC2-64, Germany) for two weeks after admission, and investigated the side of MFV elevation, presence of SAH on CT, presence of aneurysm, and the side on which surgery was performed. Results: Elevation of MFV to (more than 120 cm/sec) was found in 12 cases (54.5%) . Ipsilateral MFV was initially elevated on the side of SAH in six cases, and on the contralateral side in the other six. Contralateral MFV was elevated after ipsilateral MFV in three cases. Conclusions: Ipsilateral MFV becomes elevated earlier when SAH exists on one side of the sylvian fissure, but sometimes contralateral MFV becomes elevated earlier regardless of the side of aneurysm or surgery when SAH exists on both sides of the sylvian fissure.

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A 67-year-old woman presented with a right cervical mass which she had first noticed in May 1998. The hard elastic tumor was 4×3×3cm in size. A CT scan showed that the tumor was homogeneously enhanced. MR images (T1-WI) showed a homogenous isointense mass under the right carotid bifurcation. On B-mode ultrasonography with color flow Doppler, the tumor had a heterogeneous intensity and the margin was well demarcated. The right vagal nerve adjoined the tumor. The tumor was continuous with the cervical sympathetic nerve. Color flow Doppler showed pulsatile feeding arteries in the tumor. Conventional angiography showed that the tumor was fed by the right external carotid artery. We diagnosed the tumor as a neurinoma arising from the cervical sympathetic nerve. On Sept. 30, 1998, the cervical tumor was resected totally. On histological examination, the tumor was diagnosed as a neurinoma with components of Antoni B type. The patient showed Homer's symptoms after the operation.
B-mode ultrasonography with color flow Doppler can provide anatomical details of tumors and be a very useful tool for evaluating cervical mass lesions.

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Purpose: We demonstrated a technique for dividing large meningiomas using a light, miniaturized ultrasonic aspirator (UA) handpiece simultaneously with bipolar coagulator forceps. Representative Cases: Two large meningiomas were divided into 3 and 4 compartments, respectively, and removed. Compartmental removal using UA made it possible to locate and safely dissect important deep structures. Technique: The tumor was cut along a planned dividing plane to make a disk-like space using the UA handpiece in one hand and the bipolar coagulator forceps in the other. The bottom of the tumor wall was opened widely to safely dissect the tumor-brain boundary under direct vision. The divided compartment was retracted toward the main tumor mass and dissected with minimal injury to the surrounding tissue. Conclusion: Simultaneous use of the UA and bipolar coagulator facilitates the compartmental removal of large meningiomas in less time and with less bleeding.

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There have been many recent technological advances in ultrasound diagnostic equipment. First, I will discuss two technologies called “Micro Fine Imaging” and “Broad Band Flow Imaging”, which are already installed in a current commercial ultrasound system. I will then discuss two aspects of future technology: “Quantification of ultrasound image information” and “Three-dimensional imaging by ultrasound”. These technologies are expected to increase the available amount of diagnostic information.

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