Work

The diagnostic value of virtual unenhanced spectral CT images in acute pancreatitis: a comparison with true unenhanced images

Year: 2026

Type: article

Abstract: OBJECTIVE: To investigate whether virtual unenhanced (VUE) images generated from spectral CT using the rapid kVp switching technique can serve as a substitute for true unenhanced (TUE) images in the assessment of acute pancreatitis (AP). METHODS: This retrospective study included 90 patients diagnosed with AP according to the Revised Atlanta Classification who underwent unenhanced non-spectral CT scan and dual-phase spectral CT scans of the abdomen. VUE images for the arterial (AP-VUE) and venous phases (VP-VUE) were reconstructed using material decomposition techniques. Objective and subjective assessments were conducted on TUE, AP-VUE, and VP-VUE images. The objective evaluation included CT attenuation, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR). The subjective evaluation was performed by three readers independently and assessed image quality, lesion identification, severity grading of pancreatitis, and diagnostic confidence. RESULTS: CT attenuations differences between the TUE and VUE images were not significant for AP lesion (P = 0.110 (Pancreatitis) & 0.052 (Peripancreatic effusion)), with over 76.67% of anatomical regions showing differences within 10 HU. Compared with VP-VUE and AP-VUE images, TUE images demonstrated higher SNR and CNR overall. Diagnostic confidence scores were comparable across TUE, AP-VUE, and VP-VUE (confidence scores from 5(4, 5) to 5(5, 5), P from 0.439 to 1.000) and the diagnostic conclusions showed no significant differences as well (P > 0.05). The Balthazar CT grading system (A–E) demonstrated high concordance (Intraclass correlation coefficients > 0.8) across all image types, with no difference in AP severity assessment (P > 0.05). CONCLUSION: The diagnostic value of VUE images in AP is comparable to that of TUE images, suggesting that VUE images can serve as an alternative to reduce radiation exposure.

Source: BMC Medical Imaging

DOI: 10.1186/s12880-026-02361-9