Magnetic resonance imaging-guided, high-intensity focused ultrasound for brain tumor therapy.
OBJECTIVE
Magnetic resonance imaging-guided high-intensity focused ultrasound (MRIgFUS) is a novel technique that may have the potential for precise image-guided thermocoagulation of intracranial lesions. The system delivers small volumetric sonications from an ultrasound phased array transmitter that focuses energy selectively to destroy the target with verification by magnetic resonance imaging-generated thermal maps. A Phase I clinical study was initiated to treat patients with recurrent glioma with MRIgFUS.


METHODS
To date, three patients with histologically verified recurrent glioblastoma multiforme have been treated with MRIgFUS. All patients underwent craniectomy 7 to 10 days before therapy to create a bony window for the ultrasound treatment. Sonications were applied to induce thermocoagulation of the enhancing tumor mass. Long-term radiological follow-up and post-treatment tissue specimens were available for all patients.


RESULTS
MRIgFUS treatment resulted in immediate changes in contrast-enhanced T1-, T2-, and diffusion-weighted magnetic resonance imaging scans in the treated regions with subsequent histological evidence of thermocoagulation. In one patient, heating of brain tissue in the sonication path resulted in a secondary focus outside the target causing neurological deficit. New software modifications were developed to address this problem.


CONCLUSIONS
In this first clinical report, MRIgFUS was demonstrated to be a potentially effective means of destroying tumor tissue by thermocoagulation, although with an associated morbidity and the inherent invasive nature of the procedure requiring creation of a bone window. A modified technology to allow MRIgFUS treatment through a closed cranium is being developed.
Ram
Zvi
Z
Department of Neurosurgery, Tel Aviv Sourasky Medical Center, 6 Weizman Street, Tel Aviv 64239, Israel. zviram@inter.net.il
Cohen
Zvi R
ZR
Harnof
Sagi
S
Tal
Sigal
S
Faibel
Meir
M
Nass
Dvora
D
Maier
Stephan E
SE
Hadani
Moshe
M
Mardor
Yael
Y
D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000628:therapy*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome; D014464:Ultrasonic Therapy / Q000379:methods*