Soichiro Ishiuchi

Purpose: To investigate whether virtual-monoenergetic images (VMI) from dual-layer spectral-detector computed tomography (DLCT) improve right adrenal vein (RAV) assessment before adrenal venous sampling (AVS), and portal-venous-phase (PVP) images alone can replace conventional multiphase CT combining late-arterial phase (LAP) and PVP. Methods: Sixty-three patients with primary aldosteronism who underwent LAP and PVP DLCT before AVS were retrospectively analyzed. Conventional polyenergetic-images (PEI) and VMI at 40–70 keV (VMI _40–70 ) were reconstructed. Image noise and contrast-to-noise ratio (CNR) of RAV were quantified. VMI with the highest CNR was predefined as the best-VMI. Two radiologists evaluated four image series (PEI and best-VMI at LAP and PVP) separately for RAV visibility, accessory hepatic vein (AHV) assessability, and image noise using five-point scales (1 = worst, 5 = best). RAV detection and AHV assessability rates were compared among image series. Results: In both enhancement phases, VMI _40–70 showed lower image noise and VMI _40–60 higher CNR than PEI (all p < 0.05), with VMI ₄₀ providing the highest CNR and being designated as the best VMI. Compared to PEI at LAP, CNR was lower with PEI at PVP but higher with VMI ₄₀ at PVP (both, p < 0.001). In subjective analysis, VMI ₄₀ showed better scores than PEI for image noise (LAP: 4.0 ± 0.5 vs. 2.4 ± 0.6; PVP: 4.0 ± 0.6 vs. 2.5 ± 0.5) and RAV visibility (LAP: 4.5 ± 0.8 vs. 3.5 ± 0.8; PVP: 3.7 ± 1.0 vs. 2.6 ± 0.9) (all p < 0.001). With PEI, the RAV detection rate was lower at PVP than at LAP (54.8% vs. 89.7%, p < 0.001). Use of VMI ₄₀ at PVP achieved the same detection rate as PEI at LAP (89.7%, p = 1.0) and higher AHV assessability rate than PEI at PVP (96.8% vs. 80.2%, p < 0.001). Conclusion: DLCT-VMI improved RAV assessments before AVS. Using VMI ₄₀ for PVP provided RAV depiction equivalent to PEI at LAP and superior AHV assessability to PEI at PVP, suggesting its potential as a surrogate for dedicated multiphase CT.

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^− 3 mm²/s vs. 1.83 ± 0.70 × 10^− 3 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.