Comparison of Diagnostic Performance Between Standard Susceptibility Map‐Weighted Imaging and Susceptibility Map‐Weighted Imaging Reconstructed From Clinical SWI and Neuromelanin MRI in Early Parkinson's Disease

ABSTRACT Background Susceptibility map‐weighted imaging (SMwI) provides high accuracy for early Parkinson's disease (ePD) by enhancing nigral hyperintensity. However, standard SMwI requires dedicated acquisition; reconstruction from routinely acquired sequences may offer a practical alternative. Purpose To compare the diagnostic performance of standard SMwI with SWI‐ and neuromelanin (NM)‐driven SMwI for differentiating ePD from disease controls (DC). Study Type Retrospective. Subjects One hundred and eighty‐seven drug‐naïve ePD (age: 67.5 ± 9.4 years, 102 male) and 43 DC (age: 67.1 ± 9.2 years, 12 male). Field Strength/Sequence 3 T, multi‐echo gradient‐echo (GRE) for standard SMwI; GRE‐based NM imaging: multi‐echo GRE for SWI. Assessment Nigral hyperintensity was assessed by three neuroradiologists (4‐, 2‐, and 1‐year experience). Diagnostic performance was evaluated using clinical diagnosis for all subjects and PET for 106 subjects (98 ePD, 8 DC). PET‐based assessment included side‐based analyses accounting for PET laterality and patient‐based analyses regardless of direction. Statistical Tests Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy and area under the curve (AUC) were assessed using clinical diagnosis as reference; sensitivity, specificity, and accuracy using PET. Significance was set at p < 0.05. Results Using clinical diagnosis as reference, standard SMwI showed highest diagnostic performance (sensitivity 0.856; specificity 1.000; PPV 1.000; AUC 0.928). SWI‐driven SMwI maintained similar sensitivity ( p = 0.355) but showed significantly reduced specificity, PPV, accuracy, AUC. In the PET subgroup, side‐ and patient‐based analyses showed no differences in sensitivity ( p = 0.261, p = 0.670), specificity ( p = 1.000, p = 1.000) and accuracy ( p = 0.268, p = 0.695) between standard and SWI‐driven SMwI. Data Conclusion SWI‐driven SMwI approached the diagnostic performance of standard SMwI with PET reference but showed inferior performance with clinical diagnosis, suggesting a fallback option when dedicated SMwI is unavailable. Evidence Level 3. Technical Efficacy Stage 1.