Application of low-dose hydro-CT using SAFIRE in the evaluation of esophageal cancer

The esophageal cancer treatment strategy depends on the tumor stage according to the tumor, node and metastasis (TNM) classification. One of the methods recommended for esophageal cancer assessment is computed tomography (CT). The CT imaging is especially important for patients with contraindications for gastroscopy, which is the primary method used for assessing esophageal diseases.

The aim of this retrospective study was to evaluate the inter-rater reliability of low-dose hydro-CT with a sinogram-affirmed iterative reconstruction algorithm (SAFIRE) used for the staging of esophageal cancer by 2 independent radiologists. We also evaluated the application of this method for the diagnosis of esophageal cancer.

Low-dose hydro-CT was performed in 65 patients, and the raw data were reconstructed with SAFIRE. Obtained images were retrospectively interpreted by 2 independent and experienced radiologists. Histopathological results were used as the reference standard. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) in the diagnosis of esophageal cancer were calculated for hydro-CT. The examination of the inter-rater reliability level in the assessment of the esophageal cancer stage in the TNM classification was performed by calculating Cohen's kappa coefficient (κ) with square weights and standard errors (SEs) for kappa. Independence tests were also performed (Fisher's exact test - two-tailed, and Pearson's χ2 test).

For the diagnosis of esophageal cancer with hydro-CT, a sensitivity of 93%, a specificity of 100%, a PPV of 100%, and a NPV of 88% were observed. In the statistical analyses for the T, N and M stages, κ values greater than 0.90 and significance levels of p < 0.001 were obtained.

Hydro-CT using low-dose techniques may be a valuable diagnostic method for staging and diagnosis of esophageal cancer, especially in patients with contraindications for invasive procedures.