Visibility of the hilar lymph nodes using advanced virtual monoenergetic low-keV images for preoperative evaluation of lung cancer

概要

The purpose of our study was to evaluate the detectability of the hilar LNs using advanced virtual monoenergetic low keV images compared with early-phase contrast-enhanced CT (CE-CT).

CE-CT was acquired with dual source CT for preoperative evaluation of lung cancer at 20 and 60 s after administration of contrast media in 50 patients (32 men, 18 women, mean age: 69 years). Five kinds of images (A: 20 s/120 kV; B: 60 s/40 keV; C: 60 s/50 keV; D: 60 s/120 kV; E: 60 s/100 kV) were reconstructed. We measured the CT number of the bilateral main pulmonary arteries (PAs), pulmonary veins (PVs) and hilar LNs, and evaluated the differences in CT number (Hounsfield Units) between the PA/PV and LNs (PA-LN and PV-LN contrast).

The PA-LN contrast (HU) was 415 in image group A, 299 in B, 180 in C, 80 in D, and 100 in E. The PV-LN contrasts in each group were 306, 287, 177, 78, and 99, respectively. Image group B showed the second highest PA-LN contrast following image group A. There was no significant difference in the PV-LN contrast between image groups A and B. The PA-LN and PV-LN contrasts of image groups B and C were significantly higher than those of E.

Advanced virtual monoenergetic low keV imaging might be useful, as well as early CE- CT, for evaluating the hilar LNs.