Benign or harmful? Dual-energy CT helps providers spot the difference in lung masses

Dual-energy spectral CT (DESCT) helps providers better differentiate between lung cancer and inflammatory masses, according to a study published online Dec. 6 in Academic Radiology.

With lung cancers among the most common cancer diagnoses worldwide, care for patients includes early surgery and chemotherapy. Some masses discovered in patients, however, are benign inflammatory masses which require a different course of treatment—which includes high doses of steroids, irradiation and antibiotics.

“The differentiation between lung cancer and inflammatory masses is thus essential because of the different therapeutic approaches,” wrote lead author Wei Shu Hou, MD, with the Department of Radiology at the Shanghai Jiao Tong University School of Medicine, and colleagues.

Currently, providers commonly use multidetector-row computed tomography (MDCT) when characterizing pulmonary masses, but the authors assert that the nonspecific nature of this imaging modality make it difficult to differentiate between lung cancer and inflammatory masses.

Wei and colleagues wrote that DESCT, which is based on rapid switching between high-and low-energy data sets from view to view, can produce monochromatic images as well as material decomposition images for quantitative iodine concentration measurement.

The purpose of the study was to explore the utility of this new DESCT technology in terms of differentiating pulmonary malignant masses from inflammatory masses.

To achieve this, the team studied 60 patients with 35 lung cancers and 25 inflammatory masses. Both groups underwent DESCT scanning during arterial phase (AP) and venous phase (VP).

Net enhancement in 70 keV monochromatic images in the two regions were measured and normalized to the aorta as normalized iodine concentrations (NICs). Additionally, the slopes of spectral attenuation curves (λHU) in the two regions were also figured.

The researchers found the inflammatory masses were usually solitary, peripheral pulmonary masses with a variable CT appearance and that their peak enhancement value of 45 HU were similar to that of lung cancer’s value of 42 HU, making differentiating the two masses difficult.

“In our study, with the use of several additional parameters generated from the new DESCT imaging, we were able to demonstrate high sensitivity and specificity for differentiating inflammatory masses from malignant lung masses,” the authors wrote.

According to the authors, the net enhancement CT numbers of 70-keV images and NIC’s in the central part of the inflammatory masses were higher than that of the lung cancers in both AP and VP stages, while the discrete cosine transform (dcT) values for lung cancers was higher than those for the benign inflammatory masses.

“In conclusion,” Wei and colleagues wrote, “for contrast-enhanced dual energy spectral CT imaging with quantitative parameters such as net enhancement CT numbers in 70-keV monochromatic images, the dCT value between central and peripheral regions of lesions, NIC, and λHU of spectral attenuation curves may be a promising new method for differentiating lung cancers from inflammatory masses.”