Value of Magnetic Resonance Imaging for Skeletal Bone Age Assessment in Healthy Male Children

BACKGROUND: Skeletal bone age assessment for medical reasons is usually performed by conventional x-ray with use of ionizing radiation. Few pilot studies have shown the possible use of magnetic resonance imaging (MRI). PURPOSE: To comprehensively evaluate feasibility and value of MRI for skeletal bone age (SBA) assessment in healthy male children. MATERIALS AND METHODS: In this prospective cross-sectional study, 63 male soccer athletes with mean age of 12.35 ± 1.1 years were examined. All participants underwent 3.0 Tesla MRI with coronal T1-weighted turbo spin echo (TSE), coronal proton density (PD)–weighted turbo spin echo (TSE), and T1-weighted three-dimensional (3D) volume interpolated breath-hold examination (VIBE) sequence. Subsequently, SBA was assessed by 3 independent blinded radiologists with different levels of experience using the common Greulich-Pyle (GP) atlas and the Tanner-Whitehouse (TW2) method. RESULTS: In a mean total acquisition time of 5:04 ± 0:47 min, MR image quality was sufficient in all cases. MRI appraisal was significantly faster (P < 0.0001) by GP with mean duration of 1:22 ± 0:08 min vs. 7:39 ± 0:28 min by TW. SBA assessment by GP resulted in mean age of 12.8 ± 1.2 years, by TW 13.0 ± 1.4 years. Interrater reliabilities were excellent for both GP (ICC = 0.912 (95% confidence interval [CI] = 0.868–0.944) and TW (ICC = 0.988 (95% CI = 0.980–0.992) and showed statistical significance (P < 0.001). Subdivided, for GP, ICCs were 0.822 (95% CI = 0.680–0.907) and 0.843 (95% CI = 0.713–0.919) in Under 12 and Under 14 group. For TW, ICCs were 0.978 (95% CI = 0.958–0.989) in Under 12 and 0.979 (95% CI = 0.961–0.989) in Under 14 group. CONCLUSION: MRI is a clinically feasible, rapidly evaluable method to assess skeletal bone age of healthy male children. Using the Greulich-Pyle (GP) atlas or the Tanner-Whitehouse (TW2) method, reliable results are obtained independent of the radiologist's experience level.