New low-field extremity MRI, compacTscan: comparison with whole-body 1.5 T conventional MRI

Abstract

Low-field extremity magnetic resonance imaging (lfMRI) is currently commercially available and has been used clinically to evaluate rheumatoid arthritis (RA). However, one disadvantage of this new modality is that the field of view (FOV) is too small to assess hand and wrist joints simultaneously. Thus, we have developed a new lfMRI system, compacTscan, with a FOV that is large enough to simultaneously assess the entire wrist to proximal interphalangeal joint area. In this work, we examined its clinical value compared to conventional 1.5 tesla (T) MRI. The comparison involved evaluating three RA patients by both 0.3 T compacTscan and 1.5 T MRI on the same day. Bone erosion, bone edema, and synovitis were estimated by our new compact MRI scoring system (cMRIS) and the kappa coefficient was calculated on a joint-by-joint basis. We evaluated a total of 69 regions. Bone erosion was detected in 49 regions by compacTscan and in 48 regions by 1.5 T MRI, while the total erosion score was 77 for compacTscan and 76.5 for 1.5 T MRI. These findings point to excellent agreement between the two techniques (kappa = 0.833). Bone edema was detected in 14 regions by compacTscan and in 19 by 1.5 T MRI, and the total edema score was 36.25 by compacTscan and 47.5 by 1.5 T MRI. Pseudo-negative findings were noted in 5 regions. However, there was still good agreement between the techniques (kappa = 0.640). Total number of evaluated joints was 33. Synovitis was detected in 13 joints by compacTscan and 14 joints by 1.5 T MRI, while the total synovitis score was 30 by compacTscan and 32 by 1.5 T MRI. Thus, although 1 pseudo-positive and 2 pseudo-negative findings resulted from the joint evaluations, there was again excellent agreement between the techniques (kappa = 0.827). Overall, the data obtained by our compacTscan system showed high agreement with those obtained by conventional 1.5 T MRI with regard to diagnosis and the scoring of bone erosion, edema, and synovitis. We conclude that compacTscan is useful for diagnosis and estimation of disease activity in patients with RA.

Peripheral blood T helper type 17 frequency shows an inverse correlation with disease activity and magnetic resonance imaging-based osteitis and erosions in disease-modifying anti-rheumatic drug- and steroid-naive established rheumatoid arthritis

“…The advent of low-field strength (0Á2 Tesla) E-MRI machines has decreased the procedure cost and patient discomfort to a great extent. Studies that evaluated the role of E-MRI in rheumatoid arthritis have shown that they provided information on bone erosions and synovitis comparable to that of high-field MRI [6,7]. The low-field MRI unit displayed high specificity but only moderate sensitivity for detection of bone marrow oedema [8].…”

Subclinical inflammation with tocilizumab treatment of rheumatoid arthritis: MRI evaluation for 2 years

“…In this study, we do not use gadolinium (Gd) enhancement images. However, we previously reported that there was excellent agreement between our MRIs and whole‐body 1.5 T‐conventional MRI that used Gd enhancement (synovitis: κ = 0.827, bone edema: κ = 0.640, bone erosion: κ = 0.833) . According to many of the previous reports of subclinical inflammation, MTX and/or other conventional synthetic disease‐modifying anti‐rheumatic drugs (csDMARDs) were given to many patients.…”

“…Low‐field extremity MRI which we developed was used in this study. Compact MRI score (cMRIS), which is a modified Rheumatoid Arthritis MRI Score (RAMRIS) and is an easier system than RAMRIS to use for evaluating bone erosion, was used for the evaluation of MRI images .…”

Comparison of low-field dedicated extremity magnetic resonance imaging with articular ultrasonography in patients with rheumatoid arthritis

“…In the present study, we used 0.3-T compacTscan MRI machine to obtain MRI imaging, because this technology is easier to use, allows faster imaging, is cheaper, and takes less space than conventional 1.5-T MRI machine, although the quality of the diagnostic activity is not different among these two technologies [19]. Comparison of the MRI technology with that of US will allow use of MRI to obtain whole-hand imaging at once and render assessment of imaging quality independent of operator skill.…”