Compact Representations of Dynamic Liver MRI

描述（由申请人提供）：肝细胞癌（HCC）是最常见的恶性肝癌，在过去十年中发病率不断上升。节段性肝切除术和肝移植是当患者符合某些标准时被证明是有效的治疗选择，这些标准依赖于通过成像对HCC病变的敏感和早期检测和表征。由于肝脏可能病变太大而不能耐受大的切除或由于供体肝脏数量不足，这些治疗对大部分患者人群不可用。对于这些患者，考虑其他治疗选择，包括全身化疗。虽然治疗反应通常是基于肿瘤大小的变化来测量的，但这可能需要几个月才能发生。因此，治疗反应的敏感和早期测量预计也会显著影响治疗。正是在这种情况下，定量MR成像发挥越来越大的作用。高时间和空间分辨率的动态成像已被引入到对比增强肝脏MRI中，以克服团注时间问题并捕获传统上用于诊断的所需增强相位。然而，目前的方法仍然限于屏气或非常适度的呼吸运动。此外，读者会看到大量的图像，从中手动选择典型的动脉、门静脉和延迟相位是必要的。我们的长期目标是将MRI发展成为诊断肝脏疾病的强大方法。作为该目标的一部分，本申请的目的是将动态肝脏对比增强MRI转换为肝癌存在和进展的定量测量。我们的中心假设是，直接从原始MRI数据估计的肝动脉血流和团注到达时间的定量动力学参数图（KPM）在检测HCC方面比传统的多相MRI具有更好的诊断性能。所提出的研究的基本原理是，所得到的KPMs能够实现对比度增强行为的紧凑表示，该对比度增强行为是可再现的，并且适合于患者内和患者间的比较。我们计划通过追求以下目标来测试我们的假设：（1）开发一种成像方法，将采集的MR数据直接映射到定量动力学参数图上，以及（2）评估所开发的定量方法在接受肝移植的患者中的诊断性能。本研究的预期结果是在初始检测和随访期间表征肝脏肿瘤的更好方法。这种技术可能会产生积极的影响，因为预计 允许定量测量癌症负担，允许早期测量治疗成功或失败，并减少对肝活检的需要。

DESCRIPTION (provided by applicant): Hepatocellular carcinoma (HCC), the most prevalent malignant liver cancer, has seen an increasing incidence rate over the last decade. Segmental liver resection and liver transplantation are curative options shown to be effective when the patient meets certain criteria, which rely on a sensitive and early detection and characterization of HCC lesions with imaging. Because the liver may be too diseased to tolerate a large resection or due to insufficient numbers of donor livers, these treatments are not available for a major part of the patient population. For these patients, other treatment options are considered including systemic chemotherapy. While treatment response is conventionally measured based on tumor size change, this may take several months to occur. A sensitive and early measurement of treatment response is therefore expected to significantly impact treatment as well. It is in this context that quantitative MR imaging plays an increasing role. High temporal and spatial resolution dynamic imaging has been introduced into contrast-enhanced liver MRI to overcome bolus-timing problems and to capture the desired enhancement phases traditionally used for diagnosis. However, current methods are still limited to breath-holds or very moderate amounts of respiratory motion. Additionally, the reader is presented with a large number of images, from which a manual selection of the typical arterial, portal-venous and delayed phases is necessary. Our long-term goal is to develop MRI into a robust method for the diagnosis of liver disease. As part of this goal, it is the objective of this application is to transform dynami liver contrast enhanced MRI into a quantitative measure of liver cancer presence and progression. Our central hypothesis is that a quantitative kinetic parametric map (KPM) of hepatic arterial blood flow and bolus arrival time estimated directly from the raw MRI data will have a better diagnostic performance for detecting HCC than conventional multiple phase MRI. The rationale for the proposed research is that the resulting KPMs enable a compact representation of the contrast enhancement behavior that is reproducible and lends itself to intra- and inter-patient comparisons. We plan to test our hypothesis by pursuing the following aims: (1) develop an imaging method that maps the acquired MR data directly onto quantitative kinetic parametric maps, and (2) evaluate the diagnostic performance of the developed quantitative method in patients undergoing liver transplantation. The expected outcome of this research of this research is a better method for characterizing liver tumors during initial detection and follow-up. Such a technique is likely to have a positive impact, since it is expected to allow a quantitative measure of cancer burden, allow an early measurement of treatment success or failure and reduce the need for liver biopsy.