The purpose of this study was to use MRI and histology to compare stereotactic lesioning modalities in a large brain model of thalamotomy.
A unilateral thalamotomy was performed in piglets utilizing one of 3 stereotactic lesioning modalities: focused ultrasound (FUS), radiofrequency, and radiosurgery. Standard clinical lesioning parameters were used for each treatment; and clinical, MRI, and histological assessments were made at early (< 72 hours), subacute (1 week), and later (1–3 months) time intervals.
Histological and MRI assessment showed similar development for FUS and radiofrequency lesions. T2-weighted MRI revealed 3 concentric lesional zones at 48 hours with resolution of perilesional edema by 1 week. Acute ischemic infarction with macrophage infiltration was most prominent at 72 hours, with subsequent resolution of the inflammatory reaction and coalescence of the necrotic zone. There was no apparent difference in ischemic penumbra or “sharpness” between FUS or radiofrequency lesions. The radiosurgery lesions presented differently, with latent effects, less circumscribed lesions at 3 months, and apparent histological changes seen in white matter beyond the thalamic target. Additionally, thermal and radiation lesioning gradients were compared with modeling by dose to examine the theoretical penumbra.
In swine thalamus, FUS and radiosurgery lesions evolve similarly as determined by MRI, histological examination, and theoretical modeling. Radiosurgery produces lesions with more delayed effects and seemed to result in changes in the white matter beyond the thalamic target.
Abbreviations used in this paper:CEM = cumulative equivalent minute; FUS = focused ultrasound; GFAP = glial fibrillary acidic protein; GKRS = Gamma Knife radiosurgery; LFB = Luxol fast blue.
CohenZRZaubermannJHarnofSMardorYNassDZadicarioE: Magnetic resonance imaging-guided focused ultrasound for thermal ablation in the brain: a feasibility study in a swine model. Neurosurgery60:593–6002007
HynynenKClementGTMcDannoldNVykhodtsevaNKingRWhitePJ: 500-element ultrasound phased array system for noninvasive focal surgery of the brain: a preliminary rabbit study with ex vivo human skulls. Magn Reson Med52:100–1072004
HynynenKMcDannoldNClementGJoleszFAZadicarioEKillianyR: Pre-clinical testing of a phased array ultrasound system for MRI-guided noninvasive surgery of the brain—a primate study. Eur J Radiol59:149–1562006
McDannoldNVykhodtsevaNJoleszFAHynynenK: MRI investigation of the threshold for thermally induced blood-brain barrier disruption and brain tissue damage in the rabbit brain. Magn Reson Med51:913–9232004
NelsonELindstromPAHaymakerW: Pathological effects of ultrasound on the human brain. A study of 25 cases in which ultrasonic irradiation was used as a lobotomy procedure. J Neuropathol Exp Neurol18:489–5081959
SweetWHMarkVH: Unipolar anodal electrolytic lesions in the brain of man and cat; report of five human cases with electrically produced bulbar or mesencephalic tractotomies. AMA Arch Neurol Psychiatry70:224–2341953