Manuel Thomas J, Bancel Thomas, Tiennot Thomas, Didier Mélanie, Santin Mathieu, Daniel Maxime, Attali David, Tanter Mickael, Lehéricy Stéphane, Pyatigorskaya Nadya, Aubry Jean-François
Physics for Medicine Paris, Inserm U1273, ESPCI Paris, CNRS UMR8361, PSL University, Paris, France.
Centre de Neuro-imagerie de Recherche (CENIR), Inserm U 1127, CNRS UMR 7225, Sorbonne Université, UPMC Univ Paris 06, UMR S 1127, Institut du Cerveau et de la Moelle (ICM), F-75013 Paris, France.
Phys Med Biol. 2025 Mar 21;70(7). doi: 10.1088/1361-6560/ad4f44.
Magnetic resonance guided transcranial focused ultrasound holds great promises for treating neurological disorders. This technique relies on skull aberration correction which requires computed tomography (CT) scans of the skull of the patients. Recently, ultra-short time-echo (UTE) magnetic resonance (MR) sequences have unleashed the MRI potential to reveal internal bone structures. In this study, we measure the efficacy of transcranial aberration correction using UTE images.We compare the efficacy of transcranial aberration correction using UTE scans to CT based correction on four skulls and two targets using a clinical device (Exablate Neuro, Insightec, Israel). We also evaluate the performance of a custom ray tracing algorithm using both UTE and CT estimates of acoustic properties and compare these against the performance of the manufacturer's proprietary aberration correction software.UTE estimated skull maps in Hounsfield units (HU) had a mean absolute error of 242 ± 20 HU (= 4). The UTE skull maps were sufficiently accurate to improve pressure at the target (no correction: 0.44 ± 0.10, UTE correction: 0.79 ± 0.05, manufacturer CT: 0.80 ± 0.05), pressure confinement ratios (no correction: 0.45 ± 0.10, UTE correction: 0.80 ± 0.05, manufacturer CT: 0.81 ± 0.05), and targeting error (no correction: 1.06 ± 0.42 mm, UTE correction 0.30 ± 0.23 mm, manufacturer CT: 0.32 ± 0.22) (= 8 for all values). When using CT, our ray tracing algorithm performed slightly better than UTE based correction with pressure at the target (UTE: 0.79 ± 0.05, CT: 0.84 ± 0.04), pressure confinement ratios (UTE: 0.80 ± 0.05, CT: 0.84 ± 0.04), and targeting error (UTE: 0.30 ± 0.23 mm, CT: 0.17 ± 0.15).These 3D transcranial measurements suggest that UTE sequences could replace CT scans in the case of MR guided focused ultrasound with minimal reduction in performance which will avoid ionizing radiation exposure to the patients and reduce procedure time and cost.
磁共振引导的经颅聚焦超声在治疗神经系统疾病方面前景广阔。该技术依赖于颅骨像差校正，这需要对患者的颅骨进行计算机断层扫描（CT）。最近，超短回波时间（UTE）磁共振（MR）序列释放了MRI揭示内部骨骼结构的潜力。在本研究中，我们测量了使用UTE图像进行经颅像差校正的效果。我们使用临床设备（Exablate Neuro，Insightec，以色列），在四个颅骨和两个靶点上比较了使用UTE扫描进行经颅像差校正与基于CT的校正的效果。我们还使用声学特性的UTE和CT估计值评估了一种定制光线追踪算法的性能，并将其与制造商的专有像差校正软件的性能进行比较。UTE以亨氏单位（HU）估计的颅骨图平均绝对误差为242±20 HU（=4）。UTE颅骨图足够准确，可提高靶点处的压力（无校正：0.44±0.10，UTE校正：0.79±0.05，制造商CT：0.80±0.05）、压力限制率（无校正：0.45±0.10，UTE校正：0.80±
