Magnetic resonance spin-labeling perfusion imaging of synovitis in inflammatory arthritis at 3.0 T

Abstract

The proposed modality allows for the assessment of disease activity in arthritis without the application of contrast-medium offering a new tool for therapy monitoring. As the technique provides quantitative information on hyperaemia, it potentially offers new insights in the pathophysiology of arthritic diseases.

Diffusion-weighted MRI of bone marrow oedema, soft tissue oedema and synovitis in paediatric patients: feasibility and initial experience

“…However, some patients cannot, or do not want to, receive intravenous contrast medium for a history of allergic reaction or impaired renal function. As detection and quantification of synovitis on MRI is extremely helpful for early diagnosis and therapy surveillance in patients with chronic inflammatory arthritis, recent research efforts have focussed on native MR imaging techniques for synovitis without the need of intravenous contrast injection, such as arterial spin labelling [21]. DWI as employed in our study presents another innovative approach with promising first results and appears particularly appealing with respect to paediatric patients for merits such as short scanning time and relative insensitivity to patient movement.…”

Pixel-by-Pixel Arterial Spin Labeling Blood Flow Pattern Variation Analysis for Discrimination of Rheumatoid Synovitis: A Pilot Study

“…In a previous study, conventional ASL perfusion imaging of synovitis in inflammatory arthritis of finger and wrist joints at high-field strength was concluded to be feasible. 1 They determined a threshold for perfusion values (over 600 ml/100 g/min) to distinguish pannus from vessels, based on perfusion values of macroscopic vascular flow rather than tissue perfusion. However, the authors needed to define multiple thresholds for perfusion values to identify pannus from other tissues and found that the perfusion values of each tissue fluctuate dramatically depending on PLD times.…”

“…An arterial spin labeling (ASL) perfusion map, which is calculated by the subtraction of an image without blood preparation from that with blood preparation, is capable of quantitatively measuring microvascular perfusion characteristics of tissues without the need to administer contrast agents. It may visualize hyperemia of inflamed synovitis (pannus) of rheumatoid arthritis (RA) 1 because an increased number of capillaries is observed in the inflamed synovial membrane as compared to the normal synovial membrane. 2 , 3 However, it has a similar difficulty as conventional contrast enhanced magnetic resonance (MR) imaging of distinguishing pannus formation from the peripheral artery due to their resemblance in signal intensity.…”

“…Previous studies have attempted to extract microvascular flow from pannus by fixing the upper limit value of the synovial tissue on the ASL perfusion map. 1 However, this method may be unreliable because perfusion values are dependent on delay time (inversion time for a flow sensitive alternating inversion recovery (FIAR) sequence and post-labeling delay (PLD) for pulsed continuous ASL (pCASL)) to allow the label to reach the tissue of interest. 4 …”

Magnetresonanztomografie

“…Die ASL (arterial spin labeling)-Technik nutzt das Blut selbst als endogenes Kontrastmittel, das durch einen Inversionspuls vor der Datenauslese markiert wird. In ersten Studien bei Patienten mit Arthritis konnte eine gute Korrelation der ASL-Perfusion mit der etablierten kontrastmittelgest ü tzten MRT-Perfusion ermittelt werden [40] . Die Bedeutung der Methode kann insbesondere darin gesehen werden, dass engmaschige Verlaufskontrollen, wie sie im Rahmen von Therapiestudien gew ü nscht sind, zuk ü nftig m ö glicherweise kontrastmittelfrei ausgef ü hrt werden k ö nnen.…”