Using Variable Flip Angle (VFA) and Modified Look-Locker Inversion Recovery (MOLLI) T1 mapping in clinical OE-MRI

T1 based oxygen-enhanced MRI in tumours; a scoping review of current research

“…[7][8][9] All of these studies have corresponding conference abstracts included in the final search results. [10][11][12]…”

“…Indeed those clinical studies that opted for single slice acquisitions have struggled with co-registering images acquired during treatment with baseline data. 10,52 The accuracy and precision of T 1 determination is not equivalent between different methodologies though; VFA, e.g. consistently overestimates T 1 values in the brain.…”

“…The extent and nature of movement during OE-MRI scans will vary depending upon the anatomical area of interest; however, it is clear that appropriate image co-registration techniques are required for robust data analysis. 10,12,31 Currently, there is a large range in the duration of clinical OE-MRI scans and variations between dynamic imaging and static acquisitions. The optimal duration of the oxygen challenge in patients is not yet proven and the potential benefits of delivering multiple oxygen challenges during one imaging session thus facilitating independent component data analysis With regards to the delivery of the oxygen challenge, although there are legitimate concerns regarding the vasoconstrictive effects of hyperoxia confounding the OE-MRI signal, the evidence presented suggests that in practice this is not a significant issue.…”

Review of oxygen‐enhanced lung mri: Pulse sequences for image acquisition and T1 measurement

“…Recently, Bluemke et al compared the 3D VFA technique with modified Look-Locker inversion recovery (MOLLI) in patients with oropharyngeal squamous cell carcinoma and found that the estimation of VFA was higher than the MOLLI estimation by 27% on average. 101 Although the VFA approach is easily implemented and can provide a 3D volume T 1 map within an acceptable time, it is sensitive to the radiofrequency (RF) field B 1 . 98 The method is not recommended for measuring the pulmonary T 1 if there is no B 1 correction before the calculation.…”

Validation of single reference variable flip angle (SR‐VFA) dynamic T1 mapping with T2* correction using a novel rotating phantom

“…T 1 is a fundamental time constant in MRI acquisitions that depends on the local tissue environment and allows MRI to produce excellent soft tissue image contrast. Quantitative T 1 measurements have been used for a variety of clinical indications, such as hypoxia in tumors, 1,2 liver diseases, 3–5 pancreatitis, 6,7 heart pathologies, 8–12 pulmonary disease, 13 pulmonary cancer, 14 and beyond 15–17 . Furthermore, dynamic quantitative T 1 mapping has been used to measure oxygenation in the brain 18 and lungs, 19 as well as for local perfusion measurements using dynamic contrast enhanced imaging, 20,21 and has been considered for T 1 ‐based thermometry in monitoring thermal therapies 22–25 .…”