Diagnostic performance of photon-counting detector CT for differentiation between adrenal adenomas and metastases

Stefanie Bette; Franka Risch; Luca Canalini; Judith Becker; Eva V Leithner; Adrian Huber; Mark Haerting; Bertram Jehs; Claudia Wollny; Florian Schwarz; Kartikay Tehlan; Christian Scheurig-Muenkler; Thomas Wendler; Thomas Kroencke; Josua A Decker

doi:10.1007/s00330-024-10675-x

Diagnostic performance of photon-counting detector CT for differentiation between adrenal adenomas and metastases

Eur Radiol. 2024 Mar 14. doi: 10.1007/s00330-024-10675-x. Online ahead of print.

Authors

Stefanie Bette¹, Franka Risch¹, Luca Canalini¹, Judith Becker¹, Eva V Leithner¹, Adrian Huber¹, Mark Haerting¹, Bertram Jehs¹, Claudia Wollny¹, Florian Schwarz², Kartikay Tehlan¹, Christian Scheurig-Muenkler¹, Thomas Wendler^{1

3

4}, Thomas Kroencke^{5

6}, Josua A Decker¹

Affiliations

¹ Diagnostic and Interventional Radiology, University Hospital Augsburg, Faculty of Medicine, University of Augsburg, Stenglinstr. 2, 86156, Augsburg, Germany.
² Diagnostic and Interventional Radiology, Donau-Isar-Klinikum, Perlasberger Str. 41, 94469, Deggendorf, Germany.
³ Institute of Digital Health, University Hospital Augsburg, Augsburg, Germany.
⁴ Computer-Aided Medical Procedures and Augmented Reality, School of Computation, Information and Technology, Technical University of Munich, Munich, Germany.
⁵ Diagnostic and Interventional Radiology, University Hospital Augsburg, Faculty of Medicine, University of Augsburg, Stenglinstr. 2, 86156, Augsburg, Germany. thomas.kroencke@uk-augsburg.de.
⁶ Centre for Advanced Analytics and Predictive Sciences (CAAPS), University of Augsburg, Universitätsstr. 2, 86159, Augsburg, Germany. thomas.kroencke@uk-augsburg.de.

PMID: 38480567
DOI: 10.1007/s00330-024-10675-x

Abstract

Objectives: Aim of this study was to assess the value of virtual non-contrast (VNC) reconstructions in differentiating between adrenal adenomas and metastases on a photon-counting detector CT (PCD-CT).

Material and methods: Patients with adrenal masses and contrast-enhanced CT scans in portal venous phase were included. Image reconstructions were performed, including conventional VNC (VNC_Conv) and PureCalcium VNC (VNC_PC), as well as virtual monochromatic images (VMI, 40-90 keV) and iodine maps. We analyzed images using semi-automatic segmentation of adrenal lesions and extracted quantitative data. Logistic regression models, non-parametric tests, Bland-Altman plots, and a random forest classifier were used for statistical analyses.

Results: The final study cohort consisted of 90 patients (36 female, mean age 67.8 years [range 39-87]) with adrenal lesions (45 adenomas, 45 metastases). Compared to metastases, adrenal adenomas showed significantly lower CT-values in VNC_Conv and VNC_PC (p = 0.007). Mean difference between VNC and true non-contrast (TNC) was 17.67 for VNC_Conv and 14.85 for VNC_PC. Random forest classifier and logistic regression models both identified VNC_Conv and VNC_PC as the best discriminators. When using 26 HU as the threshold in VNC_Conv reconstructions, adenomas could be discriminated from metastases with a sensitivity of 86.7% and a specificity of 75.6%.

Conclusion: VNC algorithms overestimate CT values compared to TNC in the assessment of adrenal lesions. However, they allow a reliable discrimination between adrenal adenomas and metastases and could be used in clinical routine in near future with an increased threshold (e.g., 26 HU). Further (multi-center) studies with larger patient cohorts and standardized protocols are required.

Clinical relevance statement: VNC reconstructions overestimate CT values compared to TNC. Using a different threshold (e.g., 26 HU compared to the established 10 HU), VNC has a high diagnostic accuracy for the discrimination between adrenal adenomas and metastases.

Key points: • Virtual non-contrast reconstructions may be promising tools to differentiate adrenal lesions and might save further diagnostic tests. • The conventional and a new calcium-preserving virtual non-contrast algorithm tend to systematically overestimate CT-values compared to true non-contrast images. • Therefore, increasing the established threshold for true non-contrast images (e.g., 10HU) may help to differentiate between adrenal adenomas and metastases on contrast-enhanced CT.

Keywords: Adrenal adenomas; Photon-counting detector computed tomography; Virtual non-contrast.