Evaluation of Magnetic Resonance Imaging using Image Co-registration in Stereotactic Radiosurgery

ABSTRACT OBJECTIVE The Novalis stereotactic radiotherapy system (BrainLAB, Heimstetten, Germany) allows for precise treatment of cranial base tumors with single-fraction radiosurgery. In some cases, however, proximity of the optic nerve and chiasm is a concern. In these cases, intensity-modulated stereotactic radiosurgery (IMRS) can be used to limit the dose to these structures. IMRS planning can be labor intensive, which poses a problem when it is performed on the day of treatment. We describe our methods and results of preprocedure planning for IMRS for patients with lesions in the cavernous sinus or parasellar regions in whom the dose to the optic nerve or chiasm might exceed our acceptable tolerance dose (8 Gy). METHODS Patients whose lesions were more than 4 mm from the optic nerve and chiasm on standard magnetic resonance imaging scans but who were questionable candidates for radiosurgery because of concerns of dose to the optic nerve or chiasm were considered for IMRS. Preprocedure imaging (computed tomography and magnetic resonance imaging) was fused and analyzed using the BrainLAB BrainScan 5.3 treatment planning system. Dynamic conformal arc plans for stereotactic radiosurgery and IMRS were evaluated. Doses to the planning target volume and optic apparatus were assessed by dose-volume histograms and conformality index calculated to characterize the quality of the different plans. When IMRS was used, the preplan allowed for a rapid recalculation on the treatment day, minimizing the time patients were in the head frame before treatment. RESULTS We describe three patients with recurrent pituitary tumors and three with meningiomas. Doses were 1500 to 2000 cGy prescribed to the 80 to 96% isodose line delivered by eight to 22 fields. Tumor volumes ranged from 2.70 to 8.82 cm3 (mean, 5.7 cm3). In five of the six patients, the dynamic conformal arc plan precluded delivery of therapeutic dose without exceeding optic nerve tolerance. On the basis of 95% coverage of target volume, maximum prescription doses of 7.7 to 20.64 Gy were possible with the dynamic conformal arc plans without exceeding 8 Gy to the optic apparatus. IMRS allowed maximum doses of 20 to 31 Gy using the same optic apparatus dose restriction. No complications have occurred, and all tumors have remained stable since treatment (mean follow-up period, 30 mo). CONCLUSION We believe this pretreatment technique streamlines the process for IMRS, allowing for better patient comfort and efficient physician time use.

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Retrospective Analysis to Determine the Frequency of Symptomatic New Brain Metastases During Routine Magnetic Resonance Imaging Surveillance Following Stereotactic Radiosurgery or Whole-Brain Radiation Therapy

International Journal of Radiation Oncology*Biology*Physics ◽

10.1016/j.ijrobp.2016.06.871 ◽

2016 ◽

Vol 96 (2) ◽

pp. E111

Author(s):

D.R. Eichorn ◽

M.U. Ali ◽

A. Lesenskyj ◽

A. Potts ◽

V. Trivedi ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Radiation Therapy ◽

Magnetic Resonance ◽

Brain Metastases ◽

Stereotactic Radiosurgery ◽

Resonance Imaging ◽

Whole Brain Radiation ◽

Routine Magnetic Resonance Imaging ◽

Imaging Surveillance ◽

Brain Radiation

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Stereotactic Radiosurgery of Angiographically Occult Vascular Malformations: Indications and Preliminary Experience

Neurosurgery ◽

10.1227/00006123-199012000-00006 ◽

1990 ◽

Vol 27 (6) ◽

pp. 892-900 ◽

Cited By ~ 89

Author(s):

Douglas Kondziolka ◽

L. Dade Lunsford ◽

Robert J. Coffey ◽

David J. Bissonette ◽

John C. Flickinger

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

Stereotactic Radiosurgery ◽

Vascular Malformations ◽

Neurological Deficits ◽

Resonance Imaging ◽

University Of Pittsburgh ◽

History Of ◽

The Brain

Abstract Stereotactic radiosurgery has been shown to treat successfully angiographically demonstrated arteriovenous malformations of the brain. Angiographic obliteration has represented cure and eliminated the risk of future hemorrhage. The role of radiosurgery in the treatment of angiographically occult vascular malformations (AOVMs) has been less well defined. In the initial 32 months of operation of the 201-source cobalt-60 gamma knife at the University of Pittsburgh, 24 patients meeting strict criteria for high-risk AOVMs were treated. Radiosurgery was used conservatively; each patient had sustained two or more hemorrhages and had a magnetic resonance imaging-defined AOVM located in a region of the brain where microsurgical removal was judged to pose an excessive risk. Venous angiomas were excluded by performance of high-resolution subtraction angiography in each patient. Fifteen malformations were in the medulla, pons, and/or mesencephalon, and 5 were located in the thalamus or basal ganglia. Follow-up ranged from 4 to 24 months. Nineteen patients either improved or remained clinically stable and did not hemorrhage again during the follow-up interval. One patient suffered another hemorrhage 7 months after radiosurgery. Five patients experienced temporary worsening of pre-existing neurological deficits that suggested delayed radiation injury. Magnetic resonance imaging demonstrated signal changes and edema surrounding the radiosurgical target. Dose-volume guidelines for avoiding complications were constructed. Our initial experience indicates that stereotactic radiosurgery can be performed safely in patients with small, well-circumscribed AOVMs located in deep, critical, or relatively inaccessible cerebral locations. Because cerebral angiography is not useful in following patients with AOVMs, long-term magnetic resonance imaging and clinical studies will be necessary to determine whether the natural history of such lesions is changed by radiosurgery.

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Efficacy of magnetic resonance imaging at 3 T compared with 1.5 T in small pituitary tumors for stereotactic radiosurgery planning

Japanese Journal of Radiology ◽

10.1007/s11604-013-0262-0 ◽

2013 ◽

Vol 32 (1) ◽

pp. 22-29 ◽

Cited By ~ 3

Author(s):

Hisato Nakazawa ◽

Yuta Shibamoto ◽

Takahiko Tsugawa ◽

Yoshimasa Mori ◽

Masami Nishio ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

Stereotactic Radiosurgery ◽

Pituitary Tumors ◽

Resonance Imaging

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Three-dimensional Fast Imaging Employing Steady-state Acquisition Magnetic Resonance Imaging for Stereotactic Radiosurgery of Trigeminal Neuralgia

Neurosurgery ◽

10.1227/01.neu.0000154709.44776.50 ◽

2005 ◽

Vol 56 (3) ◽

pp. E628-E628 ◽

Cited By ~ 48

Author(s):

Gabriela-del-Rocío Chávez Chávez ◽

Antonio A.F. De Salles ◽

Timothy D. Solberg ◽

Alessandra Pedroso ◽

Dulce Espinoza ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Steady State ◽

Magnetic Resonance ◽

Trigeminal Neuralgia ◽

Stereotactic Radiosurgery ◽

Trigeminal Nerve ◽

Three Dimensional ◽

Fast Imaging ◽

Resonance Imaging ◽

Entry Zone

Abstract OBJECTIVE: The aim of this study was to demonstrate the use and applications of the three-dimensional fast imaging employing steady-state acquisition (3-D-FIESTA) magnetic resonance imaging sequence in targeting and planning for stereotactic radiosurgery of trigeminal neuralgia. METHODS: A 3-D-FIESTA sequence for visualization of cranial nerves in the cranial base was added to the routine magnetic resonance imaging scan to enhance the treatment planning for trigeminal neuralgia. T1-weighted images, 1 mm thick, were directly compared with the FIESTA sequence for the exact visualization of the trigeminal entry zone and surrounding vasculature. The target accuracy was evaluated by image fusion of computed tomographic and magnetic resonance imaging scans. The anatomy visualized with the FIESTA sequence was validated by direct inspection of the gross anatomic specimens of the trigeminal complex. RESULTS: A total of 15 consecutive patients, 10 women and 5 men, underwent radiosurgery for essential trigeminal neuralgia between April and July, 2003. The mean age of the patients was 65.2 years (range, 24–83 yr). Nine patients had right-sided symptoms. Four patients had had previous surgery (two microvascular decompression, one percutaneous rhizotomy, and one radiofrequency thermocoagulation). The 3-D-FIESTA sequence successfully demonstrated the trigeminal complex (root entry zone, trigeminal ganglion, rootlets, and vasculature) in 14 patients (93.33%). The 3-D-FIESTA sequence also allowed visualization of the branches of the trigeminal nerve inside Meckel's cavity. This exact visualization correlated precisely with the anatomic specimens. In one patient (6.66%), it was not possible to demonstrate the related vasculature. However, the other structures were clearly visualized. CONCLUSION: The 3-D-FIESTA sequence is used in this study for demonstration of the exact anatomy of the trigeminal complex for the purpose of radiosurgical planning and treatment of trigeminal neuralgia. With such imaging techniques, radiosurgical targeting of specific trigeminal nerve branches may be feasible. It has not been possible previously to target individual branches of the trigeminal nerve.

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