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  • Author or Editor: Akira Ogawa x
  • By Author: Kuzu, Yasutaka x
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Takashi Inoue, Yasutaka Kuzu, Kuniaki Ogasawara and Akira Ogawa


This study investigated the changes in the valve pressure setting of several magnetic pressure-programmable valves after exposure to a 3-tesla magnetic field.


Five each of four types of pressure-programmable shunt valves were tested: Sophy Polaris, Sophy SM8, Codman-Hakim, and Medtronic Strata. First, the valves were advanced toward the 3-tesla static magnetic field. Second, T1-, T2-, and diffusion-weighted magnetic resonance (MR) images were generated with a radiofrequency magnetic field. Any changes in the pressure setting were observed by visual inspection with a compass or radiography.

The pressure settings were changed after exposure to the static magnetic field in all programmable valves except for the Sophy Polaris. All pressure settings studied were unchanged after exposure to both static and radiofrequency magnetic fields (T1-, T2-, and diffusion-weighted MR imaging) in the Sophy Polaris.


The Sophy Polaris valve allows shunt-dependent patients who need a programmable valve to undergo 3-tesla MR imaging.

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Takaaki Beppu, Yuichi Sato, Noriyuki Uesugi, Yasutaka Kuzu, Kuniaki Ogasawara and Akira Ogawa

✓A desmoplastic infantile astrocytoma (DIA) is an extremely rare tumor that comprises a solid astrocytic tumor accompanied by a large cyst and involves the superficial cerebral cortex and leptomeninges in infants. The solid part of this type of tumor has been well described in various reports and books, but characteristics of the cystic portion have remained unclear. Because adequate resection is required to ensure a favorable prognosis, information about the cyst is very important for diagnostic purposes and surgical planning. The authors report on the clinical and histological features of the cyst in a case of a DIA. A 12-month-old boy presented with vomiting. Contrast-enhanced magnetic resonance imaging revealed a strongly enhancing single-lobed large cyst located in the deep white matter, under the solid part of the tumor attached to the dura mater of the left frontal lobe. Both the solid and cystic portions of the tumor were surgically removed. The border between the cyst wall and surrounding white matter was unclear. Histologically, the cyst wall was composed of gliosis representing a rough accumulation of reactive astrocytes, lymphocytes, and small capillary vessels in edematous parenchyma, but no tumor cells. The present case and previous reports suggest that the cyst does not contain tumor cells, even if strongly depicted on contrast-enhanced neuroimaging, and that a thickly enhancing cyst wall indicates gliosis with accumulation of numerous small vessels.

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Rob D. Dickerman, Kyle Colleb, Jonathan T. Morganb and Steve Schneiderb