Usefulness of 3T split acquisition fast spin-echo diffusion-weighted imaging for differentiating pituitary abscess from other sellar cystic lesions: a preliminary study.

Purpose: Pituitary abscess is a rare condition that can be challenging to distinguish from other sellar cystic lesions (OSCLs) due to no specific symptoms and overlapping imaging features. Accurate differentiation is crucial for appropriate treatment planning. This study aimed to evaluate the usefulness of 3T split acquisition fast spin-echo diffusion-weighted imaging (SPLICE-DWI) in differentiating pituitary abscesses from OSCLs.

Methods: We retrospectively analyzed magnetic resonance imaging (MRI) data from 32 patients with sellar cystic lesions, including 5 with pathologically confirmed pituitary abscesses and 27 with OSCLs. Conventional MRI sequences and SPLICE-DWI were performed, and apparent diffusion coefficient (ADC) values were calculated. Qualitative assessments of signal intensity on SPLICE-DWI and conventional MRI were conducted by two neuroradiologists. The diagnostic performance of these imaging parameters was evaluated using receiver operating characteristic (ROC) analysis.

Results: SPLICE-DWI successfully differentiated pituitary abscesses from OSCLs, showing significantly lower ADC values in the abscess group compared to OSCLs (0.62 ± 0.07 × 10 mm²/s vs. 1.83 ± 0.70 × 10 mm²/s, P = 0.002). ROC analysis revealed high diagnostic accuracy for DWI signal intensity (AUC = 0.89) and ADC values (AUC = 0.95). No significant differences were found in contrast-enhanced T1-weighted imaging (T1WI) features such as ring enhancement, pituitary stalk enlargement, or sphenoid sinus mucosal thickening between the two groups.

Conclusion: SPLICE-DWI is a valuable tool for the differentiation of pituitary abscesses from OSCLs, offering high diagnostic accuracy.