Aug 2026· European Journal of Radiology· Vol 204, pp.
113126
· 0 citations· 40 references
Medicine
TL;DR
VUE is quantitatively equivalent to TUE for parotid lesion attenuation and largely preserves internally validated diagnostic performance, which support reduced-dose DECT protocols with selective omission of TUE in appropriately selected patients, pending broader multicentre and multi-vendor validation.
Abstract
Background
To investigate whether virtual unenhanced (VUE) images can permit selective omission of true unenhanced (TUE) images in multiphasic parotid dual-energy CT (DECT) without compromising attenuation accuracy or diagnostic performance.
Materials And Methods
This retrospective study included 446 lesions from 436 patients with surgically confirmed parotid lesions who underwent three-phase DECT (TUE, early and late contrast); VUE was reconstructed from both contrast phases. Agreement between VUE and TUE attenuation was assessed using Bland-Altman analysis and two one-sided tests (TOST; equivalence margin, ±10 HU), both overall and across six histopathological subgroups. Lesion detection and border clarity were compared between VUE and TUE images. XGBoost-based six-category classifiers using TUE, VUE_C1, or VUE_C2 images as input were compared to evaluate diagnostic performance. The radiation dose attributable to the TUE acquisition was estimated from the dose-length product.
Results
VUE reproduced lesion attenuation with a mean bias of less than 1 HU. TOST confirmed equivalence overall and across all six subgroups (p < 0.001), with 84.3% and 81.6% of differences within ± 10 HU. Six-category XGBoost classifiers demonstrated comparable diagnostic performance across TUE, VUE_C1, and VUE_C2 baselines. SHAP feature importance showed strong correlation across models. Background gland attenuation was overestimated on VUE by 14.8 and 16.7 HU, while lesion detection and border clarity were modestly reduced. Omitting the TUE acquisition would provide an estimated dose reduction of 2.41 ± 0.37 mSv.
Conclusion
VUE is quantitatively equivalent to TUE for parotid lesion attenuation and largely preserves internally validated diagnostic performance. These findings support reduced-dose DECT protocols with selective omission of TUE in appropriately selected patients, pending broader multicentre and multi-vendor validation.
Attenuation change utilizing VUE images and iodine quantification can differentiate enhancing from nonenhancing hyperdense adnexal lesions at PCCT with excellent diagnostic performance.
Danielle Rigau, Daniel Parrott, Bhavik Bansal et al.· Abdominal Radiology· 0 citations
To evaluate the diagnostic performance of dual-energy computed tomography (DECT) in acute appendicitis by comparing attenuation characteristics across different virtual monoenergetic energy levels, virtual non-contrast, overlay, and mixed image reconstructions.
All participants underwent DECT using a dual-source scanner. Appendiceal diameter, periappendiceal findings, and attenuation values obtained from iodine maps, virtual non-contrast, overlay, mixed images, and 40, 80, and 190 keV virtual monoenergetic images were recorded. Diagnostic performance was evaluated using receiver operating characteristic analysis, and interobserver agreement was assessed using a two-way random intraclass correlation coefficient.
In this prospective observational case-control study, 20 patients with surgically or clinically confirmed acute appendicitis and 20 control subjects without appendicitis were included. Appendiceal diameter and all DECT-derived attenuation parameters were significantly higher in patients with acute appendicitis compared with controls (
P
< .001). The highest diagnostic accuracy was achieved with 40 keV virtual monoenergetic images (AUC = 0.998), followed by appendiceal diameter (AUC = 0.994) and mixed images (AUC = 0.973). Low-keV reconstructions provided markedly improved lesion conspicuity. Periappendiceal fat stranding demonstrated high diagnostic performance (sensitivity 0.95, specificity 1.0). Interobserver agreement for attenuation measurements was excellent (intraclass correlation coefficient = 0.887).
Low-keV (40 keV) virtual monoenergetic DECT imaging provides very high diagnostic accuracy for the detection of acute appendicitis and outperforms higher-keV reconstructions and other DECT image types. When combined with conventional CT findings such as appendiceal diameter and periappendiceal inflammatory changes, DECT-derived attenuation analysis represents a reliable and reproducible tool that may enhance diagnostic confidence in emergency imaging.
Mustafa Yeşilyurt, M. Kantarcı· Journal of Acute Disease· 0 citations
Long axial field-of-view (LAFOV) PET/CT systems provide up to 40-fold higher sensitivity than standard digital systems. This study evaluated the impact of reducing acquisition times in [18 F]DCFPyL (PSMA) total-body PET/CT to support future research on the development of low-dose protocols.
Eighty-five patients with prostate cancer underwent total-body PET/CT on a 194 cm-LAFOV system. Standard 8-minute list-mode acquisitions were retrospectively reconstructed into 6-, 4-, and 2-minute datasets. In a subgroup of thirty-three consecutive patients, two experts independently assessed image quality (5-point Likert scale) and E-PSMA criteria. Quantitative analysis (SUVmax, SUVmean) was performed for primary, nodal, and bone lesions.
In the whole dataset (
n
= 85) the lesion detection rate (90.5%) and classification consistency between readers and across acquisition times exceeded 95% and remained stable between the 8-minute and 2-minute reconstructions. In a sub-group of thirty-three, no significant differences were found in quantitative parameters across all acquisition times (
p
> 0.05). While image quality scores improved slightly with longer durations (ranging from 4.50 at 2 min to 4.82 at 8 min), lesion visibility remained high even at 2 min. Changes in physiological background uptake did not impact lesion quantification.
The preliminary results of the study suggest that LAFOV-PSMA-PET/CT preserves quantitative accuracy and lesion detectability even with acquisition times reduced to 2–4 min. These findings demonstrate that high-sensitivity systems might significantly shorten protocols without compromising diagnostic integrity, providing a potential rationale for further optimization of imaging protocols and for future prospective studies specifically designed to evaluate whether the administered radiotracer activity can be safely reduced to ultra-low-dose levels while maintaining diagnostic performance.
P. Alongi, A. Comelli, S. Morea et al.· Nuclear medicine and molecul...· 0 citations
Objective: To determine the diagnostic accuracy of unenhanced low-dose multi-detector computed tomography (LDMDCT) in detecting acute appendicitis, taking histopathology as the gold standard.
Study Design: Cross-sectional validation study.
Place and Duration of Study: Department of Radiology, Combined Military Hospital Rawalpindi, Pakistan, from May to Nov 2025.
Methodology: A total of 92 patients aged 18–40 years presenting with clinically suspected Acute Appendicitis were enrolled using non-probability consecutive sampling. All patients underwent unenhanced LDMDCT on a GE Optima 128-slice scanner with radiation dose maintained below 3 mSv. CT findings were evaluated against histopathological diagnosis of resected appendix specimens. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall diagnostic accuracy were calculated.
Results: The mean age was 27.4±6.8 years, and 58(63.0%) participants were male. Histopathology confirmed acute appendicitis in 51 (55.4%) patients. Unenhanced LDMDCT demonstrated sensitivity of 88.2% (95% CI: 76.1–95.6%), specificity of 87.8% (95% CI: 73.8–95.9%), PPV of 90.0%, NPV of 85.7%, and overall diagnostic accuracy of 88.0%. No statistically significant difference in diagnostic accuracy was observed across gender or age subgroups (p>0.05).
Conclusion: Unenhanced LDMDCT is a reliable and radiation-conscious imaging modality with high diagnostic accuracy for suspected acute appendicitis. Its routine adoption in emergency imaging pathways is strongly recommended to reduce unnecessary surgery and curtail radiation burden in the predominantly young population affected by this condition.
BackgroundThe value of dual-energy CT (DECT) in enhancing the diagnostic performance of the NI-RADS criteria has not been investigated.PurposeTo compare the diagnostic performance of the proposed DECT NI-RADS with conventional contrast-enhanced (CECT) NI-RADS.Materials and methodsThis retrospective study included 47 patients with head and neck squamous cell carcinoma (HNSCC) who underwent surgery, chemotherapy, or radiation therapy, followed by post-treatment DECT neck scans. Three circular regions of interest (ROIs) were placed in the primary tumor bed and contralateral normal sternocleidomastoid muscle (SCM) on 120-kVp conventional images, 40-keV images, and iodine concentration (IC) maps. Mean density (HU), spectral HU (SHU) at 40 keV, IC values, and their normalized tumor-to-SCM ratios were calculated. Differences between benign and malignant groups were assessed. Receiver operating characteristic (ROC) analysis identified the parameter with the highest area under the curve (AUC), which was used to modify the CECT NI-RADS into a DECT-based NI-RADS system. Lesions in category 2 exceeding the cutoff were upgraded to category 3, and vice versa. Diagnostic performance was compared between conventional NI-RADS and DECT-based NI-RADS.ResultsMalignant lesions showed significantly higher attenuation, IC, and normalized IC than benign post-treatment changes. Normalized IC had the highest AUC, with a cutoff of 2.769 yielding 86.7% sensitivity, 80.0% specificity, 65.0% PPV, 93.3% NPV, and 82.0% accuracy. The proposed DECT NI-RADS criteria may improve both diagnostic performance and interreader agreement compared with conventional CECT NI-RADS.ConclusionsDECT NI-RADS system, integrating normalized IC ratio, may enhance diagnostic performance and interreader agreement compared with the conventional CECT NI-RADS criteria.
T. Sananmuang, Bhuwid Chinwatanawongwan, Thanwa Sudsang· The Neuroradiology Journal· 0 citations
OBJECTIVES
To quantify the diagnostic utility of multiphase-CT as a second line imaging modality for parathyroid adenoma localisation including assessing the differences between patients undergoing second line imaging due to negative or discordant first-line imaging (MIBI SPECT/CT) results.
METHODS
Patients undergoing multiphase-CT following negative or discordant first-line imaging were collected retrospectively over a 5-year period from 2019-2023. 73 patients were included. Sensitivity, specificity, positive predictive value, negative predictive value, accuracy, positive and negative likelihood ratios of multiphase CT for preoperative parathyroid adenoma lateralisation (correct side) and localisation (correct quadrant) were calculated. Results for the whole cohort, negative imaging cohort and discordant imaging cohorts were compared.
RESULTS
Fifty-eight of the included patients were female, and 15 were male. Mean age was 56.2 ± 11.8. One-hundred and eighty-three quadrants and 98 sides were explored surgically. 69.8% patients underwent a minimally invasive surgical procedure. Across the whole cohort, multiphase CT demonstrated a sensitivity of 70.4% (95% CI 58-81) and specificity of 86.4% (79-92). For lateralisation, performance was higher with sensitivity 82.6% (72-91) and specificity 86.2% (68-96). Moderate positive likelihood ratios were also recorded as 5.26 (localisation) and 5.99 (lateralisation).
CONCLUSIONS
Multiphase CT provided reliable diagnostic accuracy for localisation and lateralisation of parathyroid adenomas in the context of discordant or negative first-line imaging. Its high specificity and moderate positive likelihood ratios make it a valuable rule-in tool that enables targeted surgical approaches.
ADVANCES IN KNOWLEDGE
This study provides one of the largest datasets in the literature. Positive results suggest that CT can be considered in cases of negative or discordant first-line imaging if minimally invasive surgical techniques are desired.
J. Cowen, Xavier Fung, Matthew Ward et al.· British Journal of Radiology· 0 citations
We use cookies to run the site and, with your consent, for analytics and to show ads.
See our Cookie Policy.
