Whole-body MRI in children aged 6–18 years. Reliability of identifying and grading high signal intensity changes within bone marrow

Abstract

Background Whole-body magnetic resonance imaging (MRI) is increasingly being used in children, however, to date there are no studies addressing the reliability of the findings. Objective To examine intra- and interobserver reliability of a scoring system for assessment of high signal areas within the bone marrow, as visualized on T2-weighted, fat-saturated images. Materials and methods Ninety-six whole-body MRIs (1.5 T) in 78 healthy volunteers (mean age: 11.5 years) and 18 children with chronic nonbacterial osteomyelitis (mean age: 12.4 years) were included. Coronal water-only Dixon T2-weighted images were used to score the left lower extremity/pelvis for high signal intensity areas, intensity (0–2 scale), extension (0–4 scale) and shape and contour in a blinded fashion by two pairs of radiologists. Results For the pelvis, grading of bone marrow signal showed moderate to good intra- and interobserver agreement with kappa values of 0.51–0.94 and 0.41–0.87, respectively. Corresponding figures for the femur were 0.61–0.68 within and 0.32–0.61 between observers, and for the tibia 0.60–0.72 and 0.51–0.73. Agreement for assessing extension was moderate to good both within and between observers for the pelvis (k = 0.52–0.85 and 0.35–0.80), for the femur (0.52–0.67 and 0.51–0.60) and for the tibia (k = 0.59–0.69 and 0.47–0.63) except for the femur metaphysis/diaphysis, with interobserver kappa values of 0.29–0.30. Scoring of shape was moderate to good within observers, but in general poorer between observers, with kappa values of 0.40–0.73 and 0.18–0.69, respectively. For contour, the corresponding figures were 0.35–0.62 and 0.09–0.54, respectively. Conclusion MRI grading of intensity and extension of high signal intensity areas within the bone marrow of pelvis and lower limb performs well and thus can be used interchangeably by different observers, while assessment of shape and contour is reliable for the same observer but is less reliable between observers. This should be considered when performing clinical trials.

Whole body magnetic resonance imaging in healthy children and adolescents

“…Prior to this study, we developed and validated a child specific scoring system for bone marrow, with signal intensity on a 0-2 scale and signal extension on a 0-4 scale being the more reliable features, with moderate to good kappa values for both inter-and intra-observer variability [17]. MR-images of the lower limbs were analyzed in consensus by two radiologists at UNN (PZ/DA, with 6 and 20 years of experience in pediatric radiology, respectively), while the upper limbs were analyzed by two radiologists at OUS (EvB/LSOM, both with 15 years of experience in pediatric radiology), using high resolution screens.…”

Machine Learning Algorithm: Texture Analysis in CNO and Application in Distinguishing CNO and Bone Marrow Growth-Related Changes on Whole-Body MRI

“…The main purpose of our study was to use ten automatic learning models to discriminate two types of hyperintense signal on STIR sequences: the inflammatory CNO one and the bone marrow one. Red bone marrow produces a signal hyperintensity that can vary from mildly to moderately increased to a fluid-like signal [ 31 ] that can mimic many pathological conditions [ 21 ]. The purpose of our study was to implement an automatic recognition system that also assists the eye of radiologists.…”

“…This latter group of patients was used to sample and to extrapolate texture data of the bone marrow growth-related changes. In the absence of histological evidence, for ethical reasons, areas of hyperintensity in the context of a healthy bone were interpreted as expression of physiological changes in bone marrow appearance related to growth in the presence of certain characteristics such as congruence with age, topographical distribution, pattern and symmetry, taking into account the notions known from older studies to the most recent bone marrow identification methods [ 22 , 31 , 32 ].…”

Whole body magnetic resonance imaging in healthy children and adolescents. Bone marrow appearances of the axial skeleton

“…Prior to this study, we devised and validated a child-specific scoring system for bone marrow on whole-body MRI. Signal-intensity and -extension proved to be the most reliable features with kappa values of moderate to good for both inter-and intra-observer variability and were used in the analysis of the images [13]. We scored focal high signal intensity areas in the bone marrow seen on the water-only Dixon T2W sequences in five anatomical regions: mandible, shoulder girdle, thorax, spine, and pelvis.…”

“…Signal intensity can be perceived differently depending on background intensity, window-and level settings and difficulties in standardizing the signal intensity scale on MRI [63,64]. To overcome this problem, we validated our scoring system [13], arranged several face-to-face calibration meetings, discussing findings and scales.…”