Assessment of lobar perfusion in smokers according to the presence and severity of emphysema: preliminary experience with dual-energy CT angiography

Abstract

The purpose of the study was to assess pulmonary perfusion on a lobar level in smokers using dual-energy computed tomography (CT). Forty-seven smokers and ten non-smokers underwent a dual-energy multi-detector CT angiogram of the chest that allowed automatic quantification of emphysema and determination of the iodine content at the level of the microcirculation (i.e. "perfusion imaging"). Emphysema was present in 37 smokers and absent in ten smokers. Smokers with an upper lobe predominance of emphysema (n = 8) had: (1) significantly lower attenuation enhancement values in the upper lobes compared with smokers without emphysema; (2) the lobes with the most severe emphysematous changes had a statistically significantly higher percentage of emphysema (p = 0.0001) and lower mean attenuation enhancement values (p = 0.0001) than the ipsilateral lobes with less severe emphysema, matching parenchymal destruction; (3) a correlation was found between the difference in percentage of emphysema between the upper and lower lobes and the difference in attenuation attenuation enhancement values in the corresponding lobes (p = 0.0355; r = -0.54). Regional alterations of lung perfusion can be depicted by dual-energy CT in smokers with predominant emphysema.

Pulmonary Microvascular Blood Flow in Mild Chronic Obstructive Pulmonary Disease and Emphysema. The MESA COPD Study

“…Similar to the present study, perfusion abnormalities were marked in mild COPD and only slightly worse in severe/very severe COPD. Other smaller studies of pulmonary perfusion in more severe COPD have found consistent associations using, variously, MRI (16,17), single photon emission tomography (47,48), and CT perfusion scanning (15,49). These studies, however, were small, single-center, and generally uncontrolled.…”

Dose and image quality at CT pulmonary angiography—comparison of first and second generation dual-energy CT and 64-slice CT

“…With the introduction of dual-source CT systems and their capability of dual-energy imaging evaluation of PE has entered a new age: This new CT generation combines thin-section collimation with the opportunity of spectral imaging [9]. Beyond emboli visualization, dual-energy CTPA contributes functional aspects: Making use of the unique x-ray absorption characteristics of iodinated contrast material at high and low photon energies (given by tube potential settings) [10,11], DECT allows to create iodine distribution maps of the lung parenchyma and to display perfusion defects caused by obstructive PE or other lung abnormalities [12][13][14][15][16][17][18][19][20].…”

Pulmonary Vasospasm in Systemic Sclerosis: Noninvasive Techniques for Detection

“…The lack of a correlation between DE-CTPA-derived intensity changes and MLA changes suggests that subtle changes in perfusion do not contribute to measurable changes in lung density in a predictable manner. While previous studies in emphysema subjects have demonstrated moderate correlations between MLA and DE-CTPA-derived perfusion, [36][37][38] these correlations have been observed in regions of increasing emphysema severity. It is also possible that differing postures adopted with each measurement technique (IGR was performed in the seated upright position, while DE-CTPA was performed supine) may have resulted in changes in pulmonary perfusion and ventilation, hampering direct comparison of the two techniques.…”