Double inversion recovery MRI versus contrast-enhanced MRI for evaluation of knee synovitis in juvenile idiopathic arthritis

Abstract

Background: Double inversion recovery (DIR) MRI has the potential to accentuate the synovium without using contrast agents, as it allows simultaneous signal suppression of fluid and fat. The purpose of this study was (1) to compare DIR MRI to conventional contrast-enhanced (CE) MRI for delineation of the synovium in the knee in children with juvenile idiopathic arthritis (JIA) and (2) to assess the agreement between DIR MRI and CE-MRI regarding maximal synovial thickness measurements.

Results: In this prospective study, 26 children with JIA who consecutively underwent 3.0-T knee MRI between January 2018 and January 2021 were included (presence of knee arthritis: 13 [50%]; median age: 14 years [interquartile range [IQR]: 11-17]; 14 girls). Median confidence to depict the synovium (0-100 mm visual analogue scale; scored by 2 readers [consensus based]) was 88 (IQR: 79-97) for DIR MRI versus 100 (IQR: 100-100) for CE-MRI (p value = < .001). Maximal synovial thickness per child (millimeters; scored by 4 individual readers) on DIR MRI was greater (p value = < .001) in the children with knee arthritis (2.4 mm [IQR: 2.1-3.1]) than in those without knee arthritis (1.4 mm [IQR: 1.0-1.6]). Good inter-technique agreement for maximal synovial thickness per child was observed (r_s = 0.93 [p value = < .001]; inter-reader reliability: ICC DIR MRI = 0.87 [p value = < .001], ICC CE-MRI = 0.90 [p value = < .001]).

Conclusion: DIR MRI adequately delineated the synovium in the knee of children with JIA and enabled synovial thickness measurement similar to that of CE-MRI. Our results demonstrate that DIR MRI should be considered as a child-friendly alternative to CE-MRI for evaluation of synovitis in children with (suspected) JIA.

Keywords: Double inversion recovery MRI; Juvenile idiopathic arthritis; Synovitis.

Fig. 1

Study participant flow diagram

Fig. 2

Images obtained in a 14-year-old boy, diagnosed with extended oligoarticular JIA, without knee arthritis. Confidence to depict the synovium was 100 (0–100 mm visual analogue scale) for the axial contrast-enhanced MRI and the axial DIR MRI. The percentage of overlap of synovial distribution patterns was scored as > 75%

Fig. 3

Images obtained in a 9-year-old girl, diagnosed with persistent oligoarticular JIA, with knee arthritis. Confidence to depict the synovium was 100 (0–100 mm visual analogue scale) for the axial contrast-enhanced MRI and 86 (0–100 mm visual analogue scale) for the axial DIR MRI. The percentage of overlap of synovial distribution patterns was scored as > 75%

Fig. 4

Bland–Altman plots. Bland–Altman plots (a = reader 1 [R.H.]; b = reader 2 [K.F.v.D.]; c = reader 3 [E.E.D.]; d = reader 4 [M.M.]) showing the per-child differences between the first and second measurement of maximal synovial thickness on DIR MRI. On the x-axis, the average of maximal synovial thickness ((measurement DIR 1 + measurement DIR 2)/2) is displayed. The y-axis reflects the difference between both measurements (measurement DIR 1 − measurement DIR 2). Indicated by horizontal lines are the mean of the differences (bias) and limits of agreement (LOA; + 1.96 SD and − 1.96 SD). ICC, intraclass correlation coefficient (based on single-measurement, absolute-agreement, two-way mixed effects model); CI, confidence interval; *p value < .05

Fig. 5

Scattered boxplots. Boxplots combined with dot density plots (a = reader 1 [R.H.]; b = reader 2 [K.F.v.D.]; c = reader 3 [E.E.D.]; d = reader 4 [M.M.]) showing the distribution of the maximal synovial thickness per child in children with JIA classified as having knee arthritis and children with JIA without knee arthritis separated by imaging technique. Whiskers indicate the maximum and minimum measured value. Lines between circles (individual measurement on DIR MRI) and triangles (individual measurement on CE-MRI) show the relationship between corresponding individual measurements. ^aMann–Whitney U test; DIR, double inversion recovery; CE, contrast-enhanced; *p value < .05