Comparing Spectral Pre-saturation with Inversion Recovery (SPIR) and Spectral Adiabatic Inversion Recovery (SPAIR) Fat suppression techniques in Magnetic Resonance Imaging of knee joint

Background: Magnetic Resonance Imaging (MRI) is regarded as the gold standard for musculoskeletal imaging due to its excellent soft-tissue contrast and multiplanar capabilities. Nevertheless, the high signal intensity of fat often obscures important anatomical and pathological details, underscoring the need for robust fat suppression techniques. Spectral Pre-saturation with Inversion Recovery (SPIR) and Spectral Adiabatic Inversion Recovery (SPAIR) are widely applied frequency-selective inversion recovery methods. Objective: This study aims to compare SPIR and SPAIR fat suppression techniques in MRI of the knee joint to determine which provides superior overall image quality for clinical application. Materials and methods: This cross-sectional study was conducted in the Department of Radiodiagnosis, Aarupadai Veedu Medical College and Hospital, Puducherry. A total of 72 patients referred for knee MRI were included using purposive sampling. Imaging was performed on a 1.5T MRI system with a dedicated knee coil, and both PDW-SPIR and PDW-SPAIR fat suppression sequences were obtained under identical parameters. Images were anonymized and independently reviewed by two experienced radiologists. Descriptive and inferential Statistical analysis was performed using the SPSS software. Results: SPAIR sequences consistently outperformed SPIR in terms of fat suppression homogeneity, reduction of artifacts, and visualization of key anatomical structures. Structures such as the cruciate ligaments, menisci, articular cartilage, and periarticular soft tissues were more distinctly delineated on PDW - SPAIR images. The differences in image quality were statistically significant (p < 0.05). Inter-observer reliability was excellent (κ = 0.88–1.00), confirming consistent evaluations across readers. Conclusion: SPAIR provides superior fat suppression and overall image quality compared to SPIR in knee MRI. SPAIR enhances diagnostic confidence in musculoskeletal imaging. Its routine incorporation into knee MRI protocols is recommended to improve the detection and assessment of subtle joint pathologies.