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| Autori principali: | , , , , , , , , |
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| Natura: | Artículo Open Access |
| Pubblicazione: |
Wiley
2025
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| Soggetti: | |
| Accesso online: | https://onlinelibrary.wiley.com/doi/10.1002/mrm.30413 |
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Sommario:
- In vivo simultaneous proton resonance frequency shift thermometry and single reference variable flip angle T1 measurements Nicholas Richards Michael Malmberg Henrik Odéen Sara Johnson Michelle Kline Robb Merrill Rock Hadley Dennis L. Parker Allison Payne Magnetic Resonance in Medicine AbstractPurposeThe single reference variable flip angle sequence with a multi‐echo stack of stars acquisition (SR‐VFA‐SoS) simultaneously measures temperature change using proton resonance frequency (PRF) shift and T1‐based thermometry methods. This work evaluates SR‐VFA‐SoS thermometry in MR‐guided focused ultrasound in an in vivo rabbit model.MethodsSimultaneous PRF shift thermometry and T1‐based thermometry were obtained in a New Zealand white rabbit model (n = 7) during MR‐guided focused ultrasound surgery using the SR‐VFA‐SoS sequence at 3 T. Distinct locations in muscle (n = 16), fat (n = 12), or the interface of both tissues (n = 23) were heated. The T1‐temperature coefficient of fat was determined using least‐squares fitting of inversion recovery‐based T1 maps of untreated fat harvested from the animal and was applied to the in vivo measured heat‐induced T1 changes to create temperature maps.ResultsUsing k‐space weighted image contrast reconstruction, temporal resolution of 1.71 s was achieved for simultaneous thermometry at 1.5 × 1.5 × 2 mm voxel resolution. PRF shift thermometry was not sensitive to heating in fat. T1 changes were observed in fat at the ultrasound focus. The mean T1‐temperature coefficient for fat was determined to be 1.9%/°C ± 0.2%/°C. Precision was 0.76°C ± 0.18°C for PRF shift thermometry in muscle and 1.93°C ± 0.60°C for T1‐based thermometry in fat. Sonications in muscle showed an increase in T1 of 2.4%/°C ± 0.9%/°C.ConclusionThe SR‐VFA‐SoS sequence was shown to simultaneously measure temperature change using PRF shift and T1‐based methods in an in vivo model, providing thermometry for both aqueous and fat tissues. 10.1002/mrm.30413 http://creativecommons.org/licenses/by-nc-nd/4.0/