Low-field magnetic resonance imaging for intraoperative use in neurosurgery: a 5-year experience

Nimsky, Christopher; Ganslandt, Oliver; Tomandl, Bernd; Buchfelder, Michael; Fahlbusch, Rudolf

doi:10.1007/s00330-002-1363-9

Cited by 77 publications

(7 citation statements)

References 58 publications

(78 reference statements)

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“…46,54,62,63 Initial studies evaluating the usefulness of iMRI for surgical removal of brain tumours have been confined largely to intrinsic lesions, and have indicated that surgeons continued resection 38% of the time after iMRI assessment of the completeness of resection following their initial attempt, which underscores the importance of intraoperative imaging in this patient population. 64 The literature suggests at least level 2 evidence supports the utility of iMRI in improving the extent of resection, survival and quality of life in patients with glioma. 62,65 Whether this therapeutic value will extend to metastatic brain tumours remains to be determined; however, as iMRI technology becomes more common, this issue will probably be resolved.…”

Section: Brain Metastases—surgical Managementmentioning

confidence: 99%

Current approaches to the treatment of metastatic brain tumours

et al. 2014

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Metastatic tumours involving the brain overshadow primary brain neoplasms in frequency and are an important complication in the overall management of many cancers. Importantly, advances are being made in understanding the molecular biology underlying the initial development and eventual proliferation of brain metastases. Surgery and radiation remain the cornerstones of the therapy for symptomatic lesions; however, image-based guidance is improving surgical technique to maximize the preservation of normal tissue, while more sophisticated approaches to radiation therapy are being used to minimize the long-standing concerns over the toxicity of whole-brain radiation protocols used in the past. Furthermore, the burgeoning knowledge of tumour biology has facilitated the entry of systemically administered therapies into the clinic. Responses to these targeted interventions have ranged from substantial toxicity with no control of disease to periods of useful tumour control with no decrement in performance status of the treated individual. This experience enables recognition of the limits of targeted therapy, but has also informed methods to optimize this approach. This Review focuses on the clinically relevant molecular biology of brain metastases, and summarizes the current applications of these data to imaging, surgery, radiation therapy, cytotoxic chemotherapy and targeted therapy.

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Section: Brain Metastases—surgical Managementmentioning

confidence: 99%

Current approaches to the treatment of metastatic brain tumours

et al. 2014

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“…This intraoperative movement of brain tissue is in the literature usually referred to as brain shift. The magnitude of such a shift can reach up to 20 mm, and the resection of big lesions during surgery can increase the deformation of the surrounding brain structures even up to 50 mm (1)(2)(3) . Such a considerable movement of tissue movement causes a significant decrease in accuracy of commercially available neuronavigation systems which are based on preoperatively acquired data only.…”

Section: Introductionmentioning

confidence: 99%

“…For this purpose, various imaging modalities have been considered, e.g. ultrasound (US) (4,5) , x-ray computed tomography (CT) (6) and magnetic resonance imaging (MRI) (1,2,7) . Especially, applying intraoperative MR supported by a navigation system offers a very convenient solution to the problem.…”

Section: Introductionmentioning

confidence: 99%

Determination of the elasticity parameters of brain tissue with combined simulation and registration

Soza¹,

Grosso²,

Nimsky³

et al. 2005

IJMRCAS

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Reliable elasticity parameters describing the behavior of a given material are an important issue in the context of physically-based simulation. In this paper we introduce a method for the determination of the mechanical properties of brain tissue. Elasticity parameters Young's modulus E and Poisson's ratio u are estimated in an iterative framework coupling a finite element simulation with image registration. Within this framework, the outcome of the simulation is parameterized with both elasticity moduli that are automatically varied until optimal image correspondence between the simulated and the intraoperative data is achieved. We calculated optimal mechanical properties of brain tissue in six cases. The statistical analysis of the obtained values showed a good correlation of the results, thus proving the value of the method. An approach combining simulation and registration for the determination of the mechanical brain tissue properties is presented. This contributes to performing reliable physically-based simulation of soft tissue movement.

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“…Recent experience with open MR systems and with MRI radiation therapy simulators[474865] suggest that this is readily achievable with a MR system with a relatively low field strength around 0.2T. The present system is based on a field strength of 0.25 T. The low field strength would be advantageous as it reduces image distortion due to an object (i.e.…”

Section: Radiation Delivery Systemmentioning

confidence: 99%

Magnetic resonance imaging for adaptive cobalt tomotherapy: A proposal

Kron

Eyles²,

Schreiner³

et al. 2006

J Med Phys

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Magnetic resonance imaging (MRI) provides excellent soft tissue contrast for oncology applications. We propose to combine a MRI scanner with a helical tomotherapy (HT) system to enable daily target imaging for improved conformal radiation dose delivery to a patient. HT uses an intensity-modulated fan-beam that revolves around a patient, while the patient slowly advances through the plane of rotation, yielding a helical beam trajectory. Since the use of a linear accelerator to produce radiation may be incompatible with the pulsed radiofrequency and the high and pulsed magnetic fields required for MRI, it is proposed that a radioactive Cobalt-60 (60Co) source be used instead to provide the radiation. An open low field (0.25 T) MRI system is proposed where the tomotherapy ring gantry is located between two sets of Helmholtz coils that can generate a sufficiently homogenous main magnetic field.It is shown that the two major challenges with the design, namely acceptable radiation dose rate (and therefore treatment duration) and moving parts in strong magnetic field, can be addressed. The high dose rate desired for helical tomotherapy delivery can be achieved using two radiation sources of 220TBq (6000Ci) each on a ring gantry with a source to axis-of-rotation distance of 75 cm. In addition to this, a dual row multi-leaf collimator (MLC) system with 15 mm leaf width at isocentre and relatively large fan beam widths between 15 and 30 mm per row shall be employed. In this configuration, the unit would be well-suited for most pelvic radiotherapy applications where the soft tissue contrast of MRI will be particularly beneficial. Non-magnetic MRI compatible materials must be used for the rotating gantry. Tungsten, which is non-magnetic, can be used for primary collimation of the fan-beam as well as for the MLC, which allows intensity modulated radiation delivery. We propose to employ a low magnetic Cobalt compound, sycoporite (CoS) for the Cobalt source material itself.Rotational delivery is less susceptible to problems related to the use of a low energy megavoltage photon source while the helical delivery reduces the negative impact of the relatively large penumbra inherent in the use of Cobalt sources for radiotherapy. On the other hand, the use of a 60Co source ensures constant dose rate with gantry rotation and makes dose calculation in a magnetic field as easy as the range of secondary electrons is limited.The MR-integrated Cobalt tomotherapy unit, dubbed ‘MiCoTo,’ uses two independent physical principles for image acquisition and treatment delivery. It would offer excellent target definition and will allow following target motion during treatment using fast imaging techniques thus providing the best possible input for adaptive radiotherapy. As an additional bonus, quality assurance of the radiation delivery can be performed in situ using radiation sensitive gels imaged by MRI.

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Low-field magnetic resonance imaging for intraoperative use in neurosurgery: a 5-year experience

Cited by 77 publications

References 58 publications

Current approaches to the treatment of metastatic brain tumours

Current approaches to the treatment of metastatic brain tumours

Determination of the elasticity parameters of brain tissue with combined simulation and registration

Magnetic resonance imaging for adaptive cobalt tomotherapy: A proposal

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