零切变 MRI 在经颅 MR 引导聚焦超声中的应用：患者筛选和治疗效率评估。

Zero TE MRI applications to transcranial MR-guided focused ultrasound: Patient screening and treatment efficiency estimation.

机构信息

hmCINAC (Centro Integral de Neurociencias), University Hospital HM Puerta del Sur, CEU-San Pablo University, Móstoles, Madrid, Spain.

Department of Radiology, University Hospital HM Puerta del Sur, Móstoles, Madrid, Spain.

出版信息

J Magn Reson Imaging. 2019 Nov;50(5):1583-1592. doi: 10.1002/jmri.26746. Epub 2019 Apr 16.

DOI:10.1002/jmri.26746

PMID:30990938

Abstract

BACKGROUND

The high acoustic impedance of the skull limits the performance of transcranial magnetic resonance-guided focused ultrasound (tcMRgFUS) therapy. Subject suitability screening is based on skull parameters estimated from computed tomography (CT) scans.

PURPOSE

To assess the feasibility of screening for tcMRgFUS based on zero echo time (ZTE) MRI, and to explore the influence of measurable skull parameters in treatment performance.

STUDY TYPE

Retrospective.

POPULATION

Sixteen patients treated with tcMRgFUS thalamotomy for tremor.

SEQUENCE

ZTE on a 3.0T GE scanner.

ASSESSMENT

Baseline CT and ZTE images were processed to extract skull measures associated with treatment success: skull density ratio (SDR), skull thickness, and angle of incidence. Eight new metrics were proposed. CT and ZTE-based measures were compared. Each subject's energy-temperature curve was processed to extract a global estimate of efficiency and a measure of nonlinearity. These parameters were then correlated with the skull measures.

STATISTICAL TESTS

Linear regression analysis to compare ZTE vs. CT-based measures, measures vs. efficiency, and measures vs. nonlinearity. Paired t-test to assess nonlinearity.

RESULTS

CT and ZTE-based measures were significantly correlated (P < 0.01). In particular, classical metrics were robustly replicated (P < 0.001). The energy-temperature curves showed a nonlinear (logarithmic) relationship (P < 0.01). This nonlinearity was greater for thicker skulls (P < 0.01). Efficiency was correlated with skull thickness (P < 0.001) and SDR (P < 0.05).

DATA CONCLUSION

The feasibility of ZTE-based screening has been proven, potentially making it possible to avoid ionizing radiation and the extra imaging session required for CT. The characterization of the influence that skull properties have on tcMRgFUS may serve to develop patient-specific heating models, potentially improving control over the treatment outcome. The relationship of skull thickness with efficiency and nonlinearity empowers the role of this metric in the definition of such models. In addition, the lower association of SDR with the energy-temperature curves emphasizes the need of revisiting this metric.

LEVEL OF EVIDENCE

3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:1583-1592.

摘要

背景

颅骨的高声阻抗限制了经颅磁共振引导聚焦超声（tcMRgFUS）治疗的性能。受试者适用性筛查是基于从计算机断层扫描（CT）扫描中估计的颅骨参数进行的。

目的

评估基于零回波时间（ZTE）MRI 进行 tcMRgFUS 筛查的可行性，并探讨可测量颅骨参数对治疗效果的影响。

研究类型

回顾性。

人群

16 例接受 tcMRgFUS 丘脑切开术治疗震颤的患者。

序列

GE 3.0T 扫描仪上的 ZTE。

评估

对基线 CT 和 ZTE 图像进行处理，以提取与治疗成功相关的颅骨测量值：颅骨密度比（SDR）、颅骨厚度和入射角。提出了 8 个新指标。比较了基于 CT 和 ZTE 的测量值。处理每个受试者的能量-温度曲线，以提取效率的全局估计值和非线性度量值。然后将这些参数与颅骨参数相关联。

统计检验

线性回归分析比较 ZTE 与 CT 基于测量值、测量值与效率、测量值与非线性。配对 t 检验评估非线性。

结果

CT 和 ZTE 基于测量值显著相关（P <0.01）。特别是，经典指标得到了稳健的复制（P <0.001）。能量-温度曲线显示出非线性（对数）关系（P <0.01）。颅骨较厚时，非线性程度更大（P <0.01）。效率与颅骨厚度（P <0.001）和 SDR（P <0.05）相关。

数据结论

已经证明了基于 ZTE 的筛查的可行性，这可能使得避免电离辐射和 CT 所需的额外成像成为可能。颅骨特性对 tcMRgFUS 的影响的特征化可能有助于开发针对特定患者的加热模型，从而有可能更好地控制治疗效果。颅骨厚度与效率和非线性的关系赋予了该指标在这些模型定义中的作用。此外，SDR 与能量-温度曲线的较低相关性强调了需要重新审视该指标。