Quantification of Lung Perfusion Blood Volume by Dual-Energy CT in Patients With and Without Chronic Obstructive Pulmonary Disease

The introduction of a dual-source CT system in the same gantry resolved many of the technical issues that previously limited the application of dual-energy CT pulmonary angiography. Dual-energy CT pulmonary angiography does not expose patients to any significant additional radiation beyond that of standard CT pulmonary angiography [1, 2]. Post-processing software is then used to subtract 80-kV from 140-kV images to produce an iodine distribution map image (lung iodine perfusion blood volume image). Lung iodine perfusion blood volume (iPBV) imaging using dual-energy CT enables the creation of iodine maps of the pulmonary parenchyma. Experience to date has shown that these studies can provide additional physiological information on patients with acute or chronic pulmonary embolism (PE) beyond the purely morphological assessment that standard CT pulmonary angiography provides [3, 4]. Recently, software (Syngo MultiModality; Siemens Healthcare) has been used for the quantification of lung iodine perfusion blood volume (iPBV), allowing objective evaluation. In addition, compared with visual analysis of PBV images, a quantitative technique can confer an advantage in avoiding any interobserver variance due to the variety of image display parameters available for dualenergy CT iPBV images. Additionally, this method, with its automatic quantification, is rapid and simple to use. Several reports have shown that perfusion reduction corresponds to air cyst or emphysema because of reduction of the pulmonary parenchyma [5, 6]. However, few reports have shown the objective quantification of lung iPBV correlating with COPD. The purpose of this study was to evaluate the objective quantification of lung iPBV with and without COPD using Syngo software. ORIGINAL ARTICLE