Quantitative Dynamic Contrast-Enhanced MRI and 18F-FDG PET/MRI in Chronic Low Back Pain
J.E. van den Berg (TU Delft - Mechanical Engineering)
Rianne van der Heijden – Mentor
Dirk Poot – Mentor
J.F. Veenland – Graduation committee member (TU Delft - Mechanical Engineering)
More Info
expand_more
Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.
Abstract
Chronic low back pain is a leading cause of disability worldwide, but most cases lack a pathoanatomical source on conventional imaging. The role of low-grade inflammation in chronic pain is increasingly understood. Hence, functional imaging techniques such as 18F-Fluorodeoxyglucose positron emission tomography (18F-FDG PET) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) may aid in the diagnosis of LBP by quantifying metabolic and microcirculatory aspects of inflammation, respectively. However, the relationship between these modalities in the lumbar spine remains unclear.
This thesis investigates the correlation between quantitative parameters of PET and DCE-MRI in the chronically painful lumbar spine. The secondary objective is to determine whether and how these correlations vary across different anatomical structures.
18F-FDG PET/DCE-MRI images from 23 patients with chronic LBP were processed using an in-house developed software pipeline (SPARCK) with custom additions/modifications. Regions of interest (ROIs) were manually segmented in eight lumbar structures in areas of increased 18F-FDG uptake and matched reference regions. PET parameters were SUVmean and SUVmax. Pharmacokinetic modeling with the Extended Tofts model was applied to obtain median and peak Ktrans, vp and k¬ep from DCE-MRI. Correlations were tested using rank-based linear mixed-effects model, accounting for repeated measures and skewed distributions. Significance levels were corrected for multiple testing.
Across the total of 179 ROIs, weak but significant positive correlations were observed between SUV and Ktrans metrics (ρLME ≈ 0.31–0.37), and between SUV and vp metrics (ρLME = 0.23) except SUVmean/vp,peak. There were no significant correlations between SUV and kep metrics across all ROIs. Structure-specific analyses showed varying correlations between SUV and Ktrans metrics: strong correlations in the intervertebral disc, moderate ρLME in the spinal canal and facet joint, no correlations in the nerve root and interspinous tissue.
Correlations between quantitative 18F-FDG PET and DCE-MRI parameters in chronic LBP are weakly positive overall and vary across anatomical structures. These results suggest that the imaging modalities capture complementary rather than redundant aspects of inflammation and that their diagnostic value may depend on the anatomical structure under investigation. Future studies should validate these findings in larger cohorts and establish baseline parameter values with asymptomatic controls.