Quantification of Supra-Aortic Arterial Wall Inflammation in Patients With Arteritis Using High Resolution Dynamic Contrast-Enhanced Magnetic Resonance Imaging Initial Results in Correlation to [18F]-FDG PET/CT

Objectives: To compare [F-18]- -fluoro-D-glucose (FDG) positron emission tomography (PET)/computed tomography (CT), used in clinical routine to detect inflamed arteries in patients with arteritis, with high resolution dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) in its ability to measure inflammation in carotid and vertebral arteries. Materials and Methods: This study was performed with written informed consent, Health Insurance Portability and Accountability Act (HIPAA) compliance, and institutional review board approval. DCE-MRI of the carotid and vertebral arteries of 17 patients with suspected arteritis was acquired at 3T (2D saturation-recovery spoiled gradient echo, in plane resolution 0.625 x 0.625 mm(2)) using a dedicated 4-channel carotid coil. Patients underwent [F-18] FDG-PET/CT within 1 week of the MRI scan. The blood pool-corrected mean standardized uptake value (mean target-to-background ratio [TBRmean]) was measured on PET/CT images at the identical location as the region-of-interest in the magnetic resonance images. MRI signal intensity data was analyzed to generate estimates of the tissue extraction fraction and interstitial volume using a 2-compartment model. Results: [F-18-FDG PET/CT TBRmean was significantly higher in patients with than without arteritis (1.55 +/- 0.34 vs. 1.06 +/- 0.14, P = 0.001). Patients diagnosed with arteritis had significantly higher extraction fractions as measured by DCE-MRI than patients without arteritis (8.79% +/- 2.19% vs. 5.82% +/- 1.13%, P = 0.002). TBRmean correlated significantly with the extraction fraction (r = 0.73, P < 0.001). DCE-MRI and FDG-PET/CT yielded the same sensitivity (86%) and specificity (90%) for the detection of arteritis. Intra- and interreader reproducibility was good with Intraclass Correlation Coefficients of 0.82 and 0.78, respectively. Conclusions: DCE-MRI is able to measure arterial inflammation reliably and noninvasively with good correlation to [F-18]-FDG PET/CT in patients suffering from arteritis of the supraaortic arteries.