Safety of the adjustable pressure ventricular valve in magnetic resonance imaging: problems and solutions

Fransen, Patrick; Dooms, Grégoire; Thauvoy, Christian

doi:10.1007/bf00598962

Cited by 21 publications

(12 citation statements)

References 4 publications

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“…It is also noteworthy that there are in vivo counterforces for certain implants that prevent these devices from presenting a hazard to patients in association with the MRI environment [25,31]. Since 1985, percutaneously adjustable CSF shunt valves have been used [27,28], but the possibility that toy magnets and the use of MRI in patients with adjustable valves might affect the adjustment mechanism has been underestimated [45,46]. In our study 50 % of the tested Codman-Medos magnetically adjustable CSF shunt valves showed a loss of adjustability after exposure to a 3.0-T static magnetic field (• ▶ Table 6).…”

mentioning

confidence: 99%

Adjustable Cerebrospinal Fluid Shunt Valves in 3.0-Tesla MRI: a Phantom Study using Explanted Devices

Akbar¹,

Aj²,

Georgi³

et al. 2009

Fortschr Röntgenstr

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mentioning

confidence: 99%

Adjustable Cerebrospinal Fluid Shunt Valves in 3.0-Tesla MRI: a Phantom Study using Explanted Devices

Akbar¹,

Aj²,

Georgi³

et al. 2009

Fortschr Röntgenstr

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“…Accidental resetting of the shunt opening pressure by the strong magnetic field of the magnetic resonance imager has been a problem for most pressure programmable devices. 7,13) Moreover, daily life commonly involves exposure to a wide variety of magnetic devices or fields. This special feature of the DSV gives a great sense of inner security to the patients, as well as the medical staff.…”

Section: Discussionmentioning

confidence: 99%

Clinical Experience With a Dual Switch Valve (Miethke) for the Management of Adult Hydrocephalus

Tsunoda

Maruki

2007

Neurol. Med. Chir.(Tokyo)

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The dual switch valve (DSV), which switches between two parallel valve chambers depending on the patient posture, was evaluated in 101 consecutive adult patients with hydrocephalus who required shunt surgery. The opening pressure was 5 or 10 cmH 2 O for the supine position and 30 or 40 cmH 2 O for the upright position depending on the sitting height. The results clearly showed that the DSV can regulate the intraventricular pressure (IVP) to 5 to 10 cmH 2 O in the supine and almost zero in the upright position, independently of posture. Ninety-four of the 101 patients received the DSV and 86 patients showed some clinical improvement. However, three patients required irrigation of subdural hematoma and six were thought to suffer underdrainage (4 probable and 2 possible). Such underdrainage probably resulted from the relatively high opening pressure in the supine position of 10 cmH 2 O and the bedridden state of these patients. This problem may be solved by the DSV with the 5 cmH 2 O setting in the supine position. The DSV can maintain physiological IVP in hydrocephalic patients independently of posture and provides generally satisfactory clinical outcome, but cannot prevent all inadequate drainage-related problems.

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“…However, the pressure setting may be accidentally changed by the effect of powerful external magnetic fields, such as those used by magnetic resonance imaging. 3,6,8) Pressure settings are reportedly also affected by weak magnetic fields associated with everyday objects, such as telephone loudspeakers, headphones, hairdryers, a magnetic pillow, and even a toy containing a magnet. 1,8,10) We present the case of a 7-year-old girl who tended to touch a television with her head during play, resulting in a change in the programmable valve pressure.…”

Section: Introductionmentioning

confidence: 99%

Alteration of the Pressure Setting of a Codman-Hakim Programmable Valve by a Television-Case Report-

Utsuki

Shimizu

Oka

et al. 2006

Neurol. Med. Chir.(Tokyo)

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A 7-year-old girl presented in semicomatose condition. She had received a ventriculoperitoneal shunt using a Codman-Hakim programmable valve. Head computed tomography demonstrated hydrocephalus and head radiography showed that the pressure setting of the shunt valve had changed to 60 mmH 2 O from 40 mmH 2 O. The pressure setting was returned to 40 mmH 2 O, and she was discharged because her clinical symptoms and hydrocephalus improved. One month later, she lost consciousness again and was transported to our hospital. Hydrocephalus and shunt valve pressure of 50 mmH 2 O were noted, and the pressure setting was returned to 40 mmH 2 O again. She was discharged without complications. We suspected that the valve pressure was caused by close contact with a television, because the patient tended to touch a television with her head during play. The valve pressure did not change after the television was placed on a high stand out of reach. We should recognize that there are many sources of weak magnetic fields that may influence a programmable valve in everyday life.

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Safety of the adjustable pressure ventricular valve in magnetic resonance imaging: problems and solutions

Cited by 21 publications

References 4 publications

Adjustable Cerebrospinal Fluid Shunt Valves in 3.0-Tesla MRI: a Phantom Study using Explanted Devices

Adjustable Cerebrospinal Fluid Shunt Valves in 3.0-Tesla MRI: a Phantom Study using Explanted Devices

Clinical Experience With a Dual Switch Valve (Miethke) for the Management of Adult Hydrocephalus

Alteration of the Pressure Setting of a Codman-Hakim Programmable Valve by a Television-Case Report-

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