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Objective: Cerebrospinal fluid (CSF) shunts are frequently used to treat hydrocephalus. The use of a programmable valve allows the operator to easily change the opening pressure. In Japan, many people use magnetic induction therapy apparatuses in their homes. However, exposing patients with adjustable CSF shunt valves to the permanent magnets included in these apparatuses may alter the shunt valve's programmed settings or permanently damage the device. Therefore, the goal of this study was to determine the health risk associated with magnetic induction therapy for patients using programmable CSF shunt valves., Methods: Five models of shunt valves from five different manufacturers, the Miethke proGAV (proGAV), the Codman Hakim programmable valve (CHPV), Sophysa Sophy model SM8 (Sophy valve), Sophysa Polaris model SPV (Polaris valve), and Strata II valve (Strata valve) were evaluated in this study. Magnetic field interactions were determined for the programmable valves by using magnetic stones with various magnetic flux densities. The maximum distance between the valve and the magnetic stone affecting the valve pressure setting was measured by X-ray., Results: The proGAV and Polaris valve were immune to unintentional reprogramming by the magnetic stones. The CHPV, Sophy valve and Strata valve, however, randomly changed settings by magnetic stones., Conclusions: Whereas the CHPV, Sophy valve and Strata valve were promptly reset by exposure to a magnetic stone with a similar strength to that used in magnetic induction therapy, proGAV and Polaris valve were resistant to inadvertent reprogramming when exposed to magnets up to 190 mT.

A 36-year-old man who was poorly compliant with his antihypertensive medication regimen was admitted to our hospital because he had nausea and an altered mental status. His disorientation increased on admission. His blood pressure was 219/156 mmHg. No focal neurologic deficits were detected, but a cranial computed tomography (CT) performed on admission revealed a low-density area in the brainstem region. Subsequent cranial T2-weighted and fluid-attenuated inversion-recovery (FLAIR) magnetic resonance imaging (MRI) performed on the same day revealed high-intensity areas in the brainstem, bilateral cerebellar hemisphere, bilateral occipito-temporal subcortical white matter, right thalamus, and the right basal ganglia region. Diffusion-weighted MRI revealed that the edema was of vasogenic origin and was not indicative of ischemia/infarction. Biochemical testing revealed a blood urea nitrogen level of 35.7 mg/dL, a serum creatinine level of 3.27 mg/dL, proteinurea (4.6 g/24 hours), and a glomerular filtration rate of 47. 6 mL/min/1.83 m2. These findings suggested a diagnosis of chronic kidney disease (CKD). The patient was diagnosed with hypertensive encephalopathy, and treatment with intravenous diltiazem was initiated. The clinical symptoms resolved 3 days after admission, and the abnormal findings in CT and MRI demonstrated completely resolved 44 days after admission. This was a rare case of reversible posterior leukoencephalopathy syndrome (RPLS) that was caused by severe hypertension and was aggravated by discontinuation of antihypertensive therapy. RPLS was caused by vasogenic edema because of sudden elevations in systemic blood pressure which exceed the autoregulatory capacity of the brain vasculature.

The hyper-vascular form of solitary fibrous tumors (SFTs) is rare and there have been few therapeutic evaluations of this entity. We encountered a hyper-vascular SFT and had difficulty removing it surgically. Following radiotherapy, both tumor size and feeder vessels were reduced and we could proceed with gross total removal. A 29-year-old woman was admitted with a 1-year history of decreasing visual acuity on the right side. Magnetic resonance imaging with gadolinium enhancement showed a homogenous enhancing mass (6x5x5 cm) which expanded the superior and inferior tentorium cerebelli. The tumor was fed by the left posterior cerebral artery, bilateral middle meningeal arteries and the right occipital artery. The first operation employed an occipital transtentorial approach and a highly vascular tumor was found. Tumor resection was limited due to severe bleeding. Histologically, the tumor showed focal hypercellularity with spindle cells and numerous capillaries. Immunohistochemically, the tumor was diffusely positive for CD34 and a diagnosis of SFT, hyper-vascular subtype, was made. After the first operation, local irradiation of a total of 40 Gy was performed. Both the tumor size and vascularity decreased dramatically. At the second operation, gross total removal was able to be performed. Radiotherapy appears effective in reducing the hyper-vascular subtype of SFT and would be one possible therapy to deal with these tumors, given their propensity of excessive bleeding during initial surgery.

Various materials have been used for cranioplasty; however, these materials frequently produce artifacts that appear when examined with conventional radiography. Computed tomography (CT), in particular, detects high density artifacts near artificial bones, which is manipulated by increased noise, and limits diagnostic performance. The purpose of this study was to evaluate the extent and shape of the artifacts due to artificial cranial bones and to consider CT imaging parameters necessary for accurate recognition of structures under the materials. Four different artificial bone materials were evaluated in this study: hydroxyapatite with 1) 40% or 2) 50% porosity, 3) titanium plate, and 4) hydroxyapatite-polymethylmethacrylate composite (HA-PMMA). CT scanning was performed with standard clinical settings. Sample specimens were placed on the right side, under the artificial bones, and CT was performed to evaluate specimen visibility. We compared the artifacts created by the four bone types listed above, and measured the CT values of those materials. With ordinary scan settings, all the artificial bones revealed high-density artifact surrounding the materials, including the inability to accurately measure specimen thickness. The upper part of the specimen in contact with the artificial bones could not be distinguished from the artifact. The CT value in the medial aspect of the artificial bones increased more than the actual CT values. Of the four artificial bone materials studied, HA-PMMA produced the fewest artifacts. Description of the structures under the artificial bones can be improved by extending the window width to approximately twice that of normal settings.

The pathogenesis and clinical treatment of dural arteriovenous fistulas (DAVF) has been well established. However, only 15 cases of spontaneous closure of DAVFs have been reported. We describe a case of spontaneous closure of a DAVF. A 60-year-old male presented with pulsatile tinnitus. Selective cerebral angiography revealed a left posterior DAVF fed by the left occipital artery and the middle meningeal artery, which drained into the left transverse sinus and sigmoid sinus. Following the initial angiography, the patient exhibited vomiting with transient disorientation and amnesia. These symptoms, along with the tinnitus, disappeared by the following day. Seven days after the initial angiography, a second angiography was performed that revealed the complete disappearance of the DAVF. Previous reports have described a long period of closure for DAVFs following initial diagnosis. Possible mechanisms for spontaneous closure of DAVFs include the development of scar tissue or a sinus thrombosis that leads to occlusion of the DAVF In this case, the DAVF closure may have been due to a sinus thrombosis induced by sinus stenosis, since occlusion of the draining sinuses coincided with the spontaneous closure of the DAVF. In cases of non-traumatic DAVF without cortical venous reflex that do not present severe symptoms, a prudent course of treatment is necessary since there is a chance of spontaneous closure of the DAVF occuring.

An interventional-radiology computed-tomography (IVR-CT)/angio system is a combination of an angiographic unit and a CT scanner. This system allows patient's movement in and out of the two imaging units, on the same table. Since June 2003, we have applied our conventional protocol for evaluation of cerebral blood perfusion during interventional radiology (IVR) procedures. We reviewed our experience using the IVR-CT/angio system and investigated the efficacy and limitations of this technique. No complications relating to radiation exposure, contrast medium use, or IVR procedures were observed. CT perfusion was useful for detecting cerebral perfusion impairment during IVR procedures. This was helpful in deciding the postoperative management. Because patients do not need to be transported to another radiographic suite to evaluate cerebral blood perfusion, the IVR-CT/angio system is ideal for safely and simply detecting cerebral perfusion defects during IVR procedures. However, it is important to consider whether there is sufficient indication for the procedure, because radiation exposure and the amount of contrast medium use are increased if the IVR procedures become difficult.