Predictors of thermal response and lesion size in patients undergoing magnetic resonance-guided focused ultrasound thalamotomy

OBJECT The authors report different MRI patterns in patients with essential tremor (ET) or obsessive-compulsive disorder (OCD) after transcranial MR-guided focused ultrasound (MRgFUS) and discuss possible causes of occasional MRgFUS failure. METHODS Between March 2012 and August 2013, MRgFUS was used to perform unilateral thalamotomy in 11 ET patients and bilateral anterior limb capsulotomy in 6 OCD patients; in all patients symptoms were refractory to drug therapy. Sequential MR images were obtained in patients across a 6-month follow-up period. RESULTS For OCD patients, lesion size slowly increased and peaked 1 week after treatment, after which lesion size gradually decreased. For ET patients, lesions were visible immediately after treatment and markedly reduced in size as time passed. In 3 ET patients and 1 OCD patient, there was no or little temperature rise (i.e., < 52°C) during MRgFUS. Successful and failed patient groups showed differences in their ratio of cortical-to-bone marrow thickness (i.e., skull density). CONCLUSIONS The authors found different MRI pattern evolution after MRgFUS for white matter and gray matter. Their results suggest that skull characteristics, such as low skull density, should be evaluated prior to MRgFUS to successfully achieve thermal rise.

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Multicenter, Randomized Phase III Study of Magnetic-Resonance-Guided Focused Ultrasound Surgery (MRgFUS) for the Treatment of Uterine Fibroids (MRgFUS TUF) Compared to Myomectomy in Symptomatic Medication and Not Sufficiently Treatable Uterine Fibroids

Case Medical Research ◽

10.31525/ct1-nct03948789 ◽

2019 ◽

Author(s):

Keyword(s):

Magnetic Resonance ◽

Focused Ultrasound ◽

Uterine Fibroids ◽

Phase Iii ◽

Ultrasound Surgery ◽

Focused Ultrasound Surgery ◽

Symptomatic Medication ◽

Phase Iii Study

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Technical and radiographic considerations for magnetic resonance imaging–guided focused ultrasound capsulotomy

Journal of Neurosurgery ◽

10.3171/2020.6.jns201302 ◽

2020 ◽

pp. 1-9 ◽

Cited By ~ 1

Author(s):

Benjamin Davidson ◽

Karim Mithani ◽

Yuexi Huang ◽

Ryan M. Jones ◽

Maged Goubran ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

Focused Ultrasound ◽

Neurosurgical Procedures ◽

Lesion Volume ◽

Angle Of Incidence ◽

Resonance Imaging ◽

Radiographic Findings ◽

Compulsive Disorder ◽

Skull Thickness

OBJECTIVEMagnetic resonance imaging–guided focused ultrasound (MRgFUS) is an emerging treatment modality that enables incisionless ablative neurosurgical procedures. Bilateral MRgFUS capsulotomy has recently been demonstrated to be safe and effective in treating obsessive-compulsive disorder (OCD) and major depressive disorder (MDD). Preliminary evidence has suggested that bilateral MRgFUS capsulotomy can present increased difficulties in reaching lesional temperatures as compared to unilateral thalamotomy. The authors of this article aimed to study the parameters associated with successful MRgFUS capsulotomy lesioning and to present longitudinal radiographic findings following MRgFUS capsulotomy.METHODSUsing data from 22 attempted MRgFUS capsulotomy treatments, the authors investigated the relationship between various sonication parameters and the maximal temperature achieved at the intracranial target. Lesion volume and morphology were analyzed longitudinally using structural and diffusion tensor imaging. A retreatment procedure was attempted in one patient, and their postoperative imaging is presented.RESULTSSkull density ratio (SDR), skull thickness, and angle of incidence were significantly correlated with the maximal temperature achieved. MRgFUS capsulotomy lesions appeared similar to those following MRgFUS thalamotomy, with three concentric zones observed on MRI. Lesion volumes regressed substantially over time following MRgFUS. Fractional anisotropy analysis revealed a disruption in white matter integrity, followed by a gradual return to near-baseline levels concurrent with lesion regression. In the patient who underwent retreatment, successful bilateral lesioning was achieved, and there were no adverse clinical or radiographic events.CONCLUSIONSWith the current iteration of MRgFUS technology, skull-related parameters such as SDR, skull thickness, and angle of incidence should be considered when selecting patients suitable for MRgFUS capsulotomy. Lesions appear to follow morphological patterns similar to what is seen following MRgFUS thalamotomy. Retreatment appears to be safe, although additional cases will be necessary to further evaluate the associated safety profile.

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