Objectives: To assess the relationship of subchondral bone tracer uptake (BTU) on SPECT/CT and meniscal pathologies on MRI in patients with painful knees.
Methods: Twenty-five patients who had MRI and SPECT/CT within 3 months without knee surgery or grade ≥3 cartilage lesions were prospectively included. Maximum values of each subchondral femorotibial area were quantified and a ratio was calculated in relation to a femoral shaft reference region, which represented the BTU background activity. Meniscal lesions were graded (intact/degeneration/tear) and meniscal extrusion (no/yes) was assessed using MRI by two musculoskeletal radiologists blinded to the SPECT/CT findings. One-tailed Spearman correlations served for statistics (p < 0.05).
Results: Knees with meniscal degeneration or tear showed a significantly higher BTU in the medial femorotibial compartment (p = 0.045) when compared to intact menisci. Meniscal degeneration was associated with an increased BTU in the lateral femorotibial compartment; however, this was not statistically significant (p = 0.143). Patients with an extruded meniscus showed significantly higher BTU compared to a non-extruded meniscus (p < 0.020).
Conclusions: Medial femorotibial BTU in SPECT/CT was associated with meniscal pathologies. Highest BTU was found in patients with meniscal tears. SPECT/CT appears to be a useful imaging modality to identify patients with overloading or early osteoarthritis.
Key points: • Meniscal degeneration and tears correlate significantly with increased BTU using SPECT/CT. • Medial meniscus extrusion is associated with an increased BTU in SPECT/CT. • SPECT/CT allows detection of overloading and early osteoarthritis.
Keywords: Knee injuries; Magnetic resonance imaging; Meniscus; Osteoarthritis; Single photon emission computed tomography/computed tomography.