- 學位論文
快速肺部動態對比劑顯影磁共振影像: 試以時空間觀點論之
On Fast Dynamic Contrast-Enhanced Lung Imaging: a Spatiotemporal Perspective
摘要
肺部動態對比顯影磁共振影像能在免於離子放射的前提下提供高解析度的多切面影像及許多關於肺的功能性資訊，一直是量測肺部微灌流的有力選項之一。然而儘管現有的研究對其在臨床及相關診斷方面的效力已多所著墨，卻鮮有任何以時空間觀點 –這一已在數種動態影像應用中頗有斬獲的理論框架 – 解析此應用的研究。本文旨在以時空間觀點分析動態對比顯影磁共振影像，並試圖以之凸顯肺部動態對比顯影之於其餘動態磁共振影像應用之獨特性。而後基於此一分析得到的觀察結果，我們透過採用k-t BLAST這一技術，展示了加速倍數可達五倍之譜的快速肺部動態對比顯影磁共振影像，並分別於健康受試者(共五位)和患者(共十三位)取得了和原本未加速之影像序列相比整體誤差率低於6%和10%的成果。我們認為時空間解析為肺部動態對比磁造影提供了一截然不同的觀點，檢視此一應用的挑戰性及獨特之處，進而揭示了透過k-t BLAST提升其同步收取影像切面數及時間解析度之可能性。
並列摘要
Dynamic Contrast Enhanced (DCE) MR Imaging has been an attractive alternative upon measuring pulmonary perfusion for it offers simultaneous acquisition of high-resolution anatomical images and various functional information without exposing to ionizing radiation. While significant amount of works have been accomplished on its feasibility towards related diagnostics, little to no works have inspect this genre of imaging with formalized spatiotemporal framework as it has long been done to several major genre of dynamic imaging. This study is an attempt to inspect DCE Lung MRI from a spatiotemporal perspective. It starts with a spatiotemporal analysis towards DCE Lung MR Images, which demonstrates the uniqueness and challenges of DCE Lung MRI among its peers. We then demonstrate the acceleration of DCE Lung MR Imaging up to a factor of 5 using spatiotemporal technique k-t BLAST. Results from the undersampled datasets show that the errors were less than 6% on 5 healthy subjects and less than 10% on 13 patients with even less inconsistencies in major perfusion parameter estimates compared with their fully sampled counterparts, suggesting feasibility and potential challenges of accelerated contrast-enhanced lung imaging in clinical examinations and potential of extending k-t BLAST into related applications. We conclude that the formulation from a spatiotemporal perspective offers an alternate view towards the uniqueness of contrast-enhance pulmonary MRI, and lead to potential increment of temporal resolution and simultaneous acquisition of more slices through the adoption of k-t BLAST acceleration.