Page 103 - Imaging of Osteoarthritis and Rheumatoid Arthritis in Hand Joints

Accuracy of low field MRI in early arthritis
rate, IgM rheumatoid factor (RF), antibodies against cyclic citrullinated peptides (anti-CCP) and conventional radiographs of hand and feet were obtained. Diagnosis was determined according to predefined definitions by the treating rheumatologists.18
Magnetic resonance imaging
Each patient underwent two MRI examinations of the wrist and 2nd-5th MCP
joints of the most symptomatic hand: One on a 0.2T extremity MRI (C-Scan;
Esaote, Genoa, Italy) and another on a 1.5T full body MRI (Discovery MR450;
GE healthcare, Milwaukee, Wisconsin). Both MRI examinations were performed
before and after intravenous administration of the gadolinium agent gadobutrol (Gadovist; Schering, Berlin, Germany), which was administered at
a dose of 0.1 mmol/kg body weight. The examinations were performed on two
separate days within one week, to allow for clearance of the contrast agent,
and to minimize the time for biological variation. The exact imaging protocols
were chosen for best image quality within a reasonable time frame after
testing sessions with multiple volunteers and patients for both systems. Those
protocols were in accordance with the guidelines of the MRI in rheumatoid
arthritis study group of the Outcome Measures in Rheumatology (OMERACT)
initiative.19 The acquisition time was 20 minutes for the 1.5T MRI and 21 minutes
for the low field extremity MRI. The complete examinations lasted between 40 6 and 60 minutes, including patient setup and contrast injection.
Low field extremity MRI
Patients were seated in a semi-sitting position with the arm abducted and the hand placed in the magnet. The hand was tightened with soft cushion pads within the centre of a dual phased array coil to minimise involuntary patient movement. A Coronal Short T1 Inversion Recovery (STIR) sequence was obtained (repetition time/echo time/inversion time, 1100/24/85 ms; matrix 192x60; slice thickness/slice gap, 3.0/0.3 mm; Field of view (FOV) 20x20 cm; 2 acquisitions) after which a T1 weighted 3D-gradient echo sequence before and after contrast injection was obtained (repetition time/echo time, 30/12 ms; flip angle 65°; matrix 192x60x80; slice thickness/slice gap, 1.0/0.0 mm; Field of view 14x14x8 cm; 1 acquisition). The gradient echo sequences were reconstructed in the coronal and axial planes.
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