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Title: | 利用傳統三維多梯度迴訊磁振造影進行上矢狀竇靜脈氧氣飽和度的量測:探討血流速度及加速度的效應 Measurements of venous oxygen saturation in the superior sagittal sinus using conventional three-dimensional multiple gradient-echo MR imaging : effects of flow velocity and acceleration |
Authors: | Chou-Ming Cheng 鄭州閔 |
Advisor: | 鍾孝文(Hsiao-Wen Chung) |
Keyword: | 靜脈氧氣飽和度,上矢狀竇,多梯度迴訊,梯度累積量歸零,血流加速度, venous oxygen saturation,superior sagittal sinus,multiple gradient-echo,gradient moment nulling,flow acceleration, |
Publication Year : | 2020 |
Degree: | 博士 |
Abstract: | 目的: 這研究發現利用磁化率磁振氧氣飽和方法評估上矢狀竇靜脈氧氣飽和度會有不同切面上的差異,進而探討血流速度及加速度效應對此現象的影響。 方法: 招募15位健康受試者進行兩次磁振造影掃描並配合一階沿身體前後側方向的血流補償以得到三維多梯度迴訊的影像。在所有切面中上矢狀竇的相位值都和迴訊時間進行線性迴歸以得到皮爾森相關係數(PCC),而其中最高值的切面受到加速度影響最小。利用這張切面的奇數迴訊所計算的靜脈氧氣飽和度評估兩次的掃描間差異及其和中央第十五張的切面間差異,而兩種差異都是利用布蘭德-奧特曼分析評估。檢視不同切面的掃描間差異和皮爾森相關係數的關係。將皮爾森相關係數高於某閾值的切面用於計算得到多切面平均靜脈氧氣飽和度的值。 結果: 在兩標準差之下,靜脈氧氣飽和度的切面相關差異分布從–16.2 到 21.5%和最近文獻結果吻合,而且此差異分布約略大於自動選取切面(–7.5~10.3%)和中央第15張切面(–8.0~8.8%)掃描間差異分布的兩倍。對皮爾森相關係數大於|-0.98|的切面,切面間靜脈氧氣飽和度的變動全都小於5.0%。利用皮爾森相關係數大於|-0.98|的切面得到之多切面平均靜脈氧氣飽和度更進一步減少掃描間差異分布至–4.7~8.2%。 結論: 血流加速度的效應可以部分解釋靜脈氧氣飽和度的切面相關差異。我們使用傳統三維多梯度迴訊序列在有脈動血流下提供可靠的靜脈氧氣飽和度之評估方法。 Purpose: This work investigates the effects of flow acceleration in the superior sagittal sinus (SSS) on slice-dependent variations in venous oxygen saturation (SvO2) estimations using susceptibility-based MR oximetry. Methods: Three-dimensional (3D) multiple gradient-echo images, with first-order flow compensation along the anterior-posterior readout direction for the first echo, were acquired twice from 15 healthy volunteers. For all slices, phases within SSS were fitted using linear regression across four TEs to obtain the Pearson's correlation coefficients (PCC), the largest of which corresponded to minimum acceleration influence. SvO2 derived from odd echoes on this slice was used to assess inter-scan difference, and compared with the central 15th slice for slice-dependent difference, both using Bland-Altman analysis. Within-scan inter-slice SvO2 consistency was examined versus PCC. Multi-slice-averaged SvO2 values were then computed from slices with PCCs above a certain threshold. Results: Slice-dependent difference in SvO2 varied from –16.2 to 21.5% at two standard deviations, in agreement with a recent report, and about twice larger than inter-scan differences for the automatically selected slice (–7.5 to 10.3%) and for the central 15th slice (–8.0 to 8.8%). For slices with PCCs higher than |–0.98|, inter-slice SvO2 deviations were all found to be less than 5.0%. Multi-slice-averaged SvO2 with PCCs higher than |–0.98| further reduced inter-scan difference to –4.7 to 8.2%. Conclusion: Slice-dependent variations in SvO2 may partly be explained by the effects of flow acceleration. Our method may enable conventional 3D multiple gradient-echo to be used for SvO2 estimations in the presence of pulsatile flow. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/50542 |
DOI: | 10.6342/NTU202002910 |
Fulltext Rights: | 有償授權 |
Appears in Collections: | 生醫電子與資訊學研究所 |
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