Clinical value of dual detector spectral CT in predicting risk of femoral head necrosis

Osteonecrosis of the femoral head (ONFH) is an ischemic bone necrosis affecting young adults; early-stage ONFH often presents with nonspecific symptoms, and delayed diagnosis may necessitate total hip arthroplasty, severely impairing quality of life and increasing healthcare costs. Although magnetic resonance imaging (MRI) is the gold standard for early detection, its use in multi-center screening is constrained by cost, scan duration, and contraindications. Dual-layer spectral CT (DLSCT) has emerged as a promising alternative, providing quantitative assessment of bone microarchitecture and perfusion. In this single-center retrospective study, 105 MRI-confirmed ONFH patients underwent DLSCT, from which CT* and electron density (ED) values were derived via calcium-suppressed imaging and expressed relative to water (%EDW), alongside visual grading, with staging per ARCO criteria. CT, CT*, and ED values declined progressively with advancing ARCO stage, and the CT*/ED ratio correlated negatively with ARCO stage (r = -0.67, P < .05). Among visual assessments, ED mapping showed the strongest correlation with ARCO staging (R = 0.767), and all quantitative parameters differed significantly across stages (P < .001). DLSCT shows high sensitivity and MRI-level staging accuracy, making it a practical alternative when MRI is not feasible.