Correlation of the Diagnostic Accuracy of Dual Energy Computed Tomography and Positron Emission Tomography/Computed Tomography in Mediastinal Lymph Node Staging in Lung Cancer: A Systematic Review.

This study aims to correlate the accuracy of derived parameters of dual-energy computed tomography (DECT) against the reference imaging modality of choice, positron-emission tomography/computed tomography (PET/CT), in the diagnosis and staging of mediastinal lymph nodes in lung cancer. An extensive database search was conducted to retrieve literature comparing the performance of DECT parameters against PET/CT. Articles published between 2010 and January 2025 were retrieved from Embase, Web of Science, PubMed/MEDLINE (Medical Literature Analysis and Retrieval System Online), CINAHL (Cumulative Index to Nursing and Allied Health Literature), and Ovid. Articles were screened and selected based on clearly defined inclusion criteria. Methodological quality, heterogeneity, and bias were evaluated, and data were extracted and synthesized to identify correlations between DECT parameters and PET/CT parameters in mediastinal lymph node staging. Five articles that met the inclusion criteria were included in this review; these consisted of 212 patients, with 314 pathological mediastinal lymph nodes. DECT attenuation parameters including arterial phase/delayed phase ratio (A/D ratio) or maximum iodine related attenuation (IRAmax) were either strongly or moderately correlated with maximum standard uptake value (SUVmax) in PET/CT (r=0.80, p =0.027; r = 0.57, p= 0.047), and iodine concentration or iodine density had a weak or no correlation with SUVmax (r=0.23, p=0.14; r=0.064, p =0.453). 18fluorine-fluorodeoxyglucose (18F-FDG) PET/CT is the imaging modality of choice in the diagnosis of suspected mediastinal lymph nodes, but it is not widely accessible and has higher cost and high false positive rates. This review investigated the potential role of DECT as a possible surrogate of 18F-FDG PET/CT and found a good correlation between DECT attenuation parameters (only) and SUVmax in 18F-FDG PET/CT. There is a significant gap in the literature in relation to the investigation of this correlation. This review found that in DECT, attenuation parameters either strongly or moderately correlated with SUVmax from 18F-FDG PET/CT and may serve as an excellent complement; however, it may be inadequate to replace 18F-FDG-PET/CT in mediastinal lymph node staging in lung cancer.