Technical Principles and Clinical Workflow of Transcranial MR-Guided Focused Ultrasound

Meng, Ying; Jones, Ryan M.; Davidson, Benjamin; Huang, Yuexi; Pople, Christopher B; Surendrakumar, Shanan; Hamani, Clement; Hynynen, Kullervo; Lipsman, Nir

doi:10.1159/000512111

Cited by 29 publications

(21 citation statements)

References 86 publications

(101 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The RCT, cohorts, and case report had low, moderate, and high risk of bias, respectively [4,[15][16][17][18]. Six studies were excluded from the qualitative synthesis (a case series that excluded all patients with hyperostosis from treatment and five reviews) [3,7,[19][20][21][22].…”

Section: Systematic Reviewmentioning

confidence: 99%

Transcranial MR-Guided Focused Ultrasound and Hyperostosis Calvariae Diffusa: Case Report and Systematic Review of the Literature

Bernstock

Torio

Raghu

et al. 2022

Stereotact Funct Neurosurg

View full text Add to dashboard Cite

We describe a 74-year-old male with intractable essential tremor (ET) and hyperostosis calvariae diffusa who was unsuccessfully treated with magnetic resonance-guided focused ultrasound (MRgFUS). A computed tomography performed prior to the procedure demonstrated a skull density ratio (SDR) of 0.37 and tricortical hyperostosis calvariae diffusa. No lesion was evident on post-MRgFUS MRI, and no improvement in the patient’s hand tremor was noted clinically. We systematically reviewed the literature to understand outcomes for those patients with hyperostosis who have undergone MRgFUS. A comprehensive literature search using the PubMed, Cochrane, and Google Scholar databases identified 3 ET patients with hyperostosis who failed treatment with MRgFUS. Clinical findings, skull characteristics, treatment parameters, and outcomes were summarized, demonstrating different patterns/degrees of bicortical hyperostosis and variable SDRs (i.e., from 0.38 to ≥0.45). Although we have successfully treated patients with bicortical hyperostosis frontalis interna (<i>n</i> = 50), tricortical hyperostosis calvariae diffusa appears to be a contraindication for MRgFUS despite acceptable SDRs.

show abstract

Section: Systematic Reviewmentioning

confidence: 99%

Transcranial MR-Guided Focused Ultrasound and Hyperostosis Calvariae Diffusa: Case Report and Systematic Review of the Literature

Bernstock

Torio

Raghu

et al. 2022

Stereotact Funct Neurosurg

View full text Add to dashboard Cite

show abstract

“…The location of the region of treatment will determine which of the 1,024 ultrasound transducer elements will be activated during treatment. The beam is then steered electronically, automatically rastering (i.e., moving from point to point) through the treatment volume with user defined spacing (69).…”

Section: Fus Mediated Bbb Openingmentioning

confidence: 99%

MRI Guided Focused Ultrasound-Mediated Delivery of Therapeutic Cells to the Brain: A Review of the State-of-the-Art Methodology and Future Applications

et al. 2021

View full text Add to dashboard Cite

Stem cell and immune cell therapies are being investigated as a potential therapeutic modality for CNS disorders, performing functions such as targeted drug or growth factor delivery, tumor cell destruction, or inflammatory regulation. Despite promising preclinical studies, delivery routes for maximizing cell engraftment, such as stereotactic or intrathecal injection, are invasive and carry risks of hemorrhage and infection. Recent developments in MRI-guided focused ultrasound (MRgFUS) technology have significant implications for treating focal CNS pathologies including neurodegenerative, vascular and malignant processes. MRgFUS is currently employed in the clinic for treating essential tremor and Parkinson's Disease by producing precise, incisionless, transcranial lesions. This non-invasive technology can also be modified for non-destructive applications to safely and transiently open the blood-brain barrier (BBB) to deliver a range of therapeutics, including cells. This review is meant to familiarize the neuro-interventionalist with this topic and discusses the use of MRgFUS for facilitating cellular delivery to the brain. A detailed and comprehensive description is provided on routes of cell administration, imaging strategies for targeting and tracking cellular delivery and engraftment, biophysical mechanisms of BBB enhanced permeability, supportive proof-of-concept studies, and potential for clinical translation.

show abstract

“…Efforts to improve the quality of guidance MRI during tMRgFUS must overcome a ubiquitous impediment to MRI: the water‐based acoustic coupling media that fill the space between the transducer surface and the skin of the patient 12 . These media acoustically couple the transducer to the subject and cool the scalp.…”

Section: Introductionmentioning

confidence: 99%

“…Efforts to improve the quality of guidance MRI during tMRgFUS must overcome a ubiquitous impediment to MRI: the water-based acoustic coupling media that fill the space between the transducer surface and the skin of the patient. 12 These media acoustically couple the transducer to the subject and cool the scalp. Water is an appealing acoustic coupling medium because it is inexpensive, biocompatible, closely matches the characteristic impedance of most tissues, and is an excellent thermal conductor.…”

Section: Introductionmentioning

confidence: 99%

Iron‐based coupling media for MRI‐guided ultrasound surgery

et al. 2022

View full text Add to dashboard Cite

Purpose In this study, we examine the effects of a recently developed, iron‐based coupling medium (IBCM) on guidance magnetic resonance (MR) scans during transcranial, magnetic‐resonance‐guided, focused ultrasound surgery (tMRgFUS) procedures. More specifically, this study tests the hypotheses that the use of the IBCM will (a) not adversely affect image quality, (b) remove aliasing from small field‐of‐view scans, and (c) decouple image quality from the motion state of the coupling fluid. Methods An IBCM, whose chemical synthesis and characterization are reported elsewhere, was used as a coupling medium during tMRgFUS procedures on gel phantoms. Guidance magnetization‐prepared rapid‐gradient‐echo (MP‐RAGE), TSE, and GRE scans were acquired with fields of view of 28 and 18 cm. Experiments were repeated with the IBCM in several distinct flow states. GRE scans were used to estimate temperature time courses as a gel target was insonated. IBCM performance was measured by computing (i) the root mean square difference (RMSD) of TSE and GRE pixel values acquired using water and the IBCM, relative to the use of water; (ii) through‐time temperature uncertainty for GRE scans; and (iii) Bland–Altman analysis of the temperature time courses. Finally, guidance TSE and GRE scans of a human volunteer were acquired during a separate sham tMRgFUS procedure. As a control, all experiments were repeated using a water coupling medium. Results Use of the IBCM reduced RMSD in TSE scans by a factor of 4 or more for all fields of view and nonstationary motion states, but did not reduce RMSD estimates in MP‐RAGE scans. With the coupling media in a stationary state, the IBCM altered estimates of temperature uncertainty relative to the use of water by less than 0.2°C. However, with a high flow state, the IBCM reduced temperature uncertainties by the statistically significant amounts (at the 0.01 level) of 0.5°C (28 cm field of view) and 5°C (18 cm field of view). Bland–Altman analyses found a 0.1°C ± 0.5°C difference between temperature estimates acquired using water and the IBCM as coupling media. Finally, scans of a human volunteer using the IBCM indicate more conspicuous grey/white matter contrast, a reduction in aliasing, and a less than 0.2°C change in temperature uncertainty. Conclusions The use of an IBCM during tMRgFUS procedures does not adversely affect image quality for TSE and GRE scans, can decouple image quality from the motion state of the coupling fluid, and can remove aliasing from scans where the field of view is set to be much smaller than the spatial extent of the coupling fluid.

show abstract

Technical Principles and Clinical Workflow of Transcranial MR-Guided Focused Ultrasound

Cited by 29 publications

References 86 publications

Transcranial MR-Guided Focused Ultrasound and Hyperostosis Calvariae Diffusa: Case Report and Systematic Review of the Literature

Transcranial MR-Guided Focused Ultrasound and Hyperostosis Calvariae Diffusa: Case Report and Systematic Review of the Literature

MRI Guided Focused Ultrasound-Mediated Delivery of Therapeutic Cells to the Brain: A Review of the State-of-the-Art Methodology and Future Applications

Iron‐based coupling media for MRI‐guided ultrasound surgery

Contact Info

Product

Resources

About