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

Zusammenfassung

Ziel: Die Zahl klinischer Hochfeld-MR-Tomografen nimmt stark zu. Es liegen nur wenige Daten zu Wechselwirkungen zwischen Magneten von 3,0 Tesla-Feldstärke und magnetisch einstellbaren Hydrozephalus-Shunt-Ventilen vor. Diese wurden ausschließlich an fabrikneuen Ventilen erhoben; die Aussagekraft für In-vivo-Bedingungen ist daher eingeschränkt. In dieser Studie am Messphantom wurden explantierte Ventile als realistischeres Modell verwendet, um die sicherheitsrelevante Funktionalität der Ventile zu prüfen und um Bildgebungsartefakte, Scherkräfte und Erhitzung der metallischen Implantate systematisch zu erfassen. Material und Methoden: 16 explantierte Codman-Medos- und Sophy-SU8-Shunt-Ventile, alle funktionstüchtig, wurden dem statischen Magnetfeld des 3,0 T MRT-Geräts ausgesetzt. Die Artefakt- und Auslöschungsuntersuchung als auch die Erwärmungsuntersuchung wurden unter Verwendung von standardisierten diagnostischen MR-Sequenzen mit unterschiedlichen SAR-Werten durchgeführt. Die translatorische Anziehungskraft für die verstellbaren Ventile wurde anhand des Ablenkungs-Winkel-Tests bestimmt. Um die Verstellbarkeit und die Funktion der Ventile zu testen, wurde das sphärische Phantom mit dem Ventil ins Isocenter des MR-Geräts platziert und dem statischen Magnetfeld des 3,0 T für 0,25 bis zu 12 h (wiederholte Exposition: 1- bis 12-mal) einschließlich der Ein- und Ausfahrprozeduren ausgesetzt. Ergebnisse: Der Durchmesser der MRT-Artefakte betrug 10 – 70 mm und waren besonders ausgeprägt in T 2*w-Sequenzen. Eine durch das MRT induzierte relevante Erwärmung der Ventile ergab sich nicht. Die auf das Ventil wirkenden magnetischen Kräfte waren im Normbereich. Reproduzierbare Einstellungsfehler wurden bei 6 Ventilen festgestellt. Schlussfolgerung: Bis Empfehlungen bezüglich Untersuchungen von Hydrozephalus-Patienten in 3,0T-MRT möglich sind, sind größer angelegten Studien notwendig.

Abstract

Purpose: Considering the rapidly increasing number of clinical high-field MR imagers and the lack of data regarding interference with magnetically adjustable cerebrospinal fluid (CSF) shunt valves, valve safety was assessed with regard to magnetic field interactions: imaging artifacts, heating, magnetic forces, and functional changes in a phantom study at 3.0 Tesla using explanted devices as a realistic model for in vivo conditions. Materials and Methods: Sixteen explanted Codman-Medos and Sophy-SU8 shunt valves, all in perfect working order, were selected and exposed to a 3.0 T static magnetic field. Valve-induced imaging artifacts and signal drop-outs and the heating experiments were evaluated using standard diagnostic MR sequences with different SAR values. Translational attraction for the adjustable valves was assessed using the deflection angle method. To test adjustability and function, the spherical phantom containing the valve was placed in the isocenter of the MR scanner and exposed to a static magnetic field of 3.0 T for 0.25 to 12 hours (repeated exposure 1 – 12 times), including typical entrance and move-out procedures. Results: The diameters of imaging artifacts ranged from 10 – 70 mm and were most prominent on T 2*w sequences. There was no relevant MR-imaging-related heating. Magnetic forces were not critical. Reproducible adjustment failures occurred in 6 valves. Conclusion: Until suggestions can be made concerning the exposure of hydrocephalic patients to 3.0T-MRI, further testing is necessary.

Key words

adjustable cerebrospinal fluid shunt valves - Codman-Medos valves - hydrocephalus - 3.0-T MRI - failure of adjustability

References

• 1 Kalousdian S, Karlan M S, Williams M A. Silicone elastomer cerebrospinal fluid shunt systems. Council on Scientific Affairs, American Medical Association.  Neurosurgery. 1998;  42 887-892
• 2 Medical Data International (3 / 1996) .U. S. markets for neurointerventional, neuroradiology and less-invasive neurosurgery products. #RP 891 234; 1995 – 2000,. CA, USA; Invine
• 3 Bondurant C P, Jimenez D F. Epidemiology of cerebrospinal fluid shunting.  Pediatr Neurosurg. 1995;  23 254-258
• 4 Hoglund M, Tisell M, Wikkelso C. Incidence of surgery for hydrocephalus in adults surveyed: same number afflicted by hydrocephalus as by multiple sclerosis.  Lakartidningen. 2001;  98 1681-1685
• 5 Del Bigio M R. Epidemiology and direct economic impact of hydrocephalus: a community based study.  Can J Neurol Sci. 1998;  25 123-126
• 6 Cochrane D D, Kestle J. Ventricular shunting for hydrocephalus in children: patients, procedures, surgeons and institutions in English Canada, 1989 – 2001.  Eur J Pediatr Surg. 2002;  12 S6-S11
• 7 Patwardhan R V, Nanda A. Implanted ventricular shunts in the United States: the billion-dollar-a-year cost of hydrocephalus treatment.  Neurosurgery. 2005;  56 139-144
• 8 Zemack G, Romner B. Seven years of clinical experience with the programmable Codman Hakim valve: a retrospective analysis of 583 patients.  J Neurosurg. 2000;  92 941-948
• 9 Miyake H, Ohta T, Kajimoto Y. et al . A clinical survey of hydrocephalus and current treatment for hydrocephalus in Japan: analysis by nationwide questionnaire.  Childs Nerv Syst. 1999;  15 363-368
• 10 Rohde V, Mayfrank L, Ramakers V T. et al . Four-year experience with the routine use of the programmable Hakim valve in the management of children with hydrocephalus.  Acta Neurochir. 1998;  140 1127-1134
• 11 Vanneste J A. Diagnosis and management of normal-pressure hydrocephalus.  J Neurol. 2000;  247 5-14
• 12 Joseph P Hornak. The Basic of MRI. Rochester Institute of Technology, Magnetic Resonance Laboratory, Rochester, NY, 1996 – 2007. Accessed August 18, 2007 http://www.cis.rit.edu/htbook/mri
• 13 Baudendistel K T, Heverhagen J T, Knopp M V. Klinisches MRT bei 3 Tesla: Aktueller Stand.  Radiologe. 2004;  44 11-18
• 14 Bernstein M A, Huston 3 rd J, Lin C. et al . High-resolution intracranial and cervical MRA at 3.0T: technical considerations and initial experience.  Magn Reson Med. 2001;  46 955-962
• 15 Campeau N G, Huston 3 rd J, Bernstein M A. et al . Magnetic resonance angiography at 3.0 Tesla: initial clinical experience.  Top Magn Reson Imaging. 2001;  12 183-204
• 16 Thulborn K R. Clinical rationale for very-high-field (3.0T) functional magnetic resonance imaging.  Top Magn Reson Imaging. 1999;  10 37-50
• 17 Scarabino T, Nemore F, Giannatempo G M. et al . 3.0T magnetic resonance in neuroradiology.  Eur Radiol. 2003;  48 154-164
• 18 Regier M, Nolte-Ernsting C, Adam G. et al . Intraindividual comparison of image quality in MR urography at 1.5 and 3 tesla in an animal model.  Röntgenstr Fortschr. 2008;  180 915-921
• 19 Rohr A, Riedel C, Reimann G. et al . Pseudotumor cerebri: quantitative in-vivo measurements of markers of intracranial hypertension.  Röntgenstr Fortschr. 2008;  180 884-890, German
• 20 Horger M, Schulze M, Mroue A. et al . Radiologic imaging of primary CNS lymphomas.  Röntgenstr Fortschr. 2008;  180 863-866, German, no abstract available
• 21 Mönninghoff C, Maderwald S, Theysohn J M. et al . Evaluation of intracranial aneurysms with 7T versus 1.5T time-of-flight MR angiography – initial experience.  Röntgenstr Fortschr. 2009;  181 16-23
• 22 Shellock F G, Crues J V. MR procedures: biologic effects, safety, and patient care.  Radiology. 2004;  232 635-652
• 23 Schmitt F, Grosu D, Purdy D. 3 Tesla-MRT: Der Erfolg höherer Feldstärken.  Radiologe. 2004;  44 31-48
• 24 Biller A, Bartsch A, Knaus C. et al . Neuroradiologische Diagnostik bei Patienten mit sensorineuralem Hörverlust vor Cochlea-Implantation.  Röntgenstr Fortschr. 2007;  179 901-913
• 25 Shellock F G, Wilson S F, Mauge C P. Magnetically programmable shunt valve: MRI at 3-Tesla.  Magn Reson Imaging. 2007;  25 1116-121
• 26 Akbar M, Stippich C, Aschoff A. Magnetic resonance imaging and cerebrospinal fluid shunt valves.  N Engl J Med. 2005;  353 1413-1414
• 27 Ortler M, Kostron H, Felber S. Transcutaneous pressure-adjustable valves and magnetic resonance imaging: an ex vivo examination of the Codman-Medos programmable valve and the Sophy adjustable pressure valve.  Neurosurgery. 1997;  40 1050-1057
• 28 Fransen P, Dooms G, Thauvoy C. Safety of the adjustable pressure ventricular valve in magnetic resonance imaging: problems and solutions.  Neuroradiology. 1992;  34 508-509
• 29 Fransen P. Transcutaneous pressure-adjustable valves and magnetic resonance imaging: an ex vivo examination of the Codman-Medos programmable valve and the Sophy adjustable pressure valve.  Neurosurgery. 1998;  42 430
• 30 Shellock F G, Habibi R, Knebel J. Programmable CSF Shunt Valve, in vitro assessment of MR imaging safety at 3 T.  AJNR Am J Neuroradiol. 2006;  27 661-665
• 31 Shellock F G. Reference manual for magnetic resonance safety, implants, and devices. Los Angeles (CA); Biomedical Research Publishing Group 2006
• 32 Cosman E R. Radiofrequency lesions. Gildenberg PL, Tasker RR Textbook of stereotactic and functional neurosurgery New York; McGraw-Hill 1998
• 33 International standard: neurosurgical implants – sterile, single-use hydrocephalus shunts and components. ISO 7197: 1989 (E) TC 150 /SC3-N 86. Geneva; International Organization of Standardization 1994
• 34 Standard practice for evaluation and specifying implantable shunt assemblies for neurosurgical application. Proposed revision of standard draft. West Conshohocken, Pa; American Society of Testing and Materials 1992
• 35 Shellock F G, Gounis M, Wakhloo A. Detachable coil for cerebral aneurysms: in vitro evaluation of magnet field interactions, heating, and artifacts at 3-Tesla.  AJNR Am J Neuroradiol. 2005;  26 363-366
• 36 American Society for Testing and Materials (ASTM) International: F 2182 – 02 .Test method for measurement of radio-frequency induced heating near passive implants during magnetic resonance imaging. Annual Book of ASTM Standards: Medical Devices and Services. Vol. 13.01. West Conshohocken, Pa; American Society for Testing and Materials 2003
• 37 Shellock F G. Thermal responses in human subjects exposed to magnetic resonance imaging.  Ann N Y Acad Sci. 1992;  649 260-272
• 38 Shellock F G, Schaefer D J, Kanal E. Physiologic responses to an MR imaging procedure performed at a specific absorption rate of 6.0 W/kg.  Radiology. 1994;  192 865-868
• 39 Rezai A R, Finelli D, Nuenhuis J A. et al . Neurostimulation systems for deep brain stimulation: in vitro evaluation of magnetic resonance imaging-related heating at 1.5 Tesla.  J Magn Reson Imaging. 2002;  15 241-250
• 40 Bhavaraju N C, Negaraddi V, Chetlapalli S R. et al . Electrical and thermal behaviour of non-ferrous noble metal electrodes exposed to MRI fields.  Magn Reson Imaging. 2001;  20 351-357
• 41 Georgi J C, Stippich C, Tronnier V M. et al . Active deep brain stimulation during MRI: a feasibility study.  Magn Reson Med. 2004;  51 380-388
• 42 Shellock F G, Begnaud J, Inman D M. VNS Therapy System: in vitro evaluation of MRI-related heating and function at 1.5- and 3.0-Tesla.  Neuromodulation. 2006;  9 204-213
• 43 American Society for Testing and Materials (ASTM) International: F 2052 .Standard test method for measurement of magnetically induced displacement force on passive implants in the magnetic resonance environment. In: Annual Book of ASTM Standards: Medical Devices and Services. Vol. 13.01. West Conshohocken, Pa; American Society for Testing and Materials 2001
• 44 Sommer T, Maintz D, Schmiedel A. et al . Hochfeld-Magnetresonanztomographie: Magnetische Anziehungs- und Rotationskräfte auf metallische Implantate bei 3,0T.  Röntgenstr Fortschr. 2004;  176 731-738
• 45 Anderson R C, Walker M L, Viner J M. Adjustment and malfunction of programmable valve after exposure to toy magnets.  J Neurosurg. 2004;  101 222-225
• 46 Miwa K, Kondo H, Sakai N. Pressure changes observed in Codman-Medos programmable valves following magnetic exposure and filliping.  Childs Nerv Syst. 2001;  17 150-153
• 47 Mauge C, Lilienfeld S. Magnetic resonance imaging and cerebrospinal fluid valves.  N Engl J Med. 2006;  354 531-532, author reply 531 – 532
• 48 Lindner D, Preul C, Trantakis C. Effect of 3T MRI on the function of shunt valves-Evaluation of Paedi GAV, Dual Switch and proGAV.  Eur J Radiol. 2005;  56 56-59
• 49 Mauer U M, Schuler J, Kunz U. The hakim programmable valve: reasons for reprogramming failures.  J Neurosurg. 2007;  107 788-791
• 50 Kurosaki K, Hamada H, Hayashi N. et al . A rare case of shunt malfunction attributable to blockage of a Codman-Hakim programmable shunt valve.  Childs Nerv Syst. 2002;  18 183-185
• 51 Inoue T, Kuzu Y, Ogasawara K. et al . Effect of 3-tesla magnetic resonance imaging on various programmable shunt valves.  J Neurosurg. 2005;  103 163-165
• 52 Aschoff A, Kremer P, Benesch C. Overdrainage and shunt technology. A critical comparison of programmable, hydrostatic and variable-resistance valves and flow-reducing devices.  Childs Nerv Syst. 1995;  11 193-202
• 53 Ludemann W, Rosahl S K, Kaminsky J. et al . Reliability of a new adjustable shunt device without the need for readjustment following 3-Tesla MRI.  Childs Nerv Syst. 2005;  21 227-229