The
major obstacle for HIFU technology in brain tumor therapy is skull bone as the
focused US field is disturbed and most of the US energy is absorbed by the
skull bone. These difficulties have been overcome for the development of
adaptive focusing techniques and large-sized phased array US transducers.
Trans-cranial MRgFUS has been established and the clinical potential
applications are researched in a fast-growing field of neuropathic pain and
brain tumor therapy. MRgFUS system may be used to temporarily disrupt the
blood-brain barrier for drug delivery to brain tumors.
A pilot study included 15 patients who underwent MRgFUS for the treatment of medication-refractory essential tremor. The results showed total tremor scores improved from 54.9 to 24.3 (P=0.001). The application of MRgFUS in 13 patients with chronic Parkinson's disease was reported. The authors showed the accuracy, safety and feasibility of the MRgFUS pallidothalamic tractotomy.
The
clinical feasibility of trans-cranial MRgFUS was evaluated by McDannold et al. Three glioblastoma patients underwent this
procedure of multiple focused ultrasound exposures. The authors demonstrated
the beam from HIFU at the brain with the magnetic resonance temperature
imaging. However, MRgFUS seemed not to achieve thermal coagulation.
Trans-cranial
MRgFUS could be a treatment option for brain diseases. HIFU modality for
functional neurosurgery was shown by a clinical study where 9 patients
suffering from chronic neuropathic pain were included and all treatments were
all well tolerated. The results show the helpful clinical utility of
trans-cranial HIFU modality for brain functional diseases. Large randomized
clinical trials are needed to assess the safety and efficacy of trans-cranial
HIFU therapy for brain tumor and neuropathic pain.