Pulmonary perfusion imaging is conventionally performed by lung scintigraphy using technetium-labeled albumin spheres that are temporarily trapped in the pulmonary capillaries and thus visualize pulmonary perfusion. Although per definition lung perfusion is a dynamic process of pulmonary blood flow over time, imaging of the pulmonary capillary bed or blood volume is an accepted surrogate for lung perfusion. By visualizing the contrast agent distribution in the lung parenchyma, spiral dual energy CT angiography (CTA) provides the opportunity to assess pulmonary vessels and pulmonary perfusion within one fast examination. There is already substantial evidence that pulmonary CTA and dual energy CT (DECT) lung perfusion visualization have complimentary roles in the diagnosis of pulmonary embolism. A simultaneous detection of a clot in a pulmonary artery in the pulmonary CTA and of a perfusion defect in DECT lung perfusion in the corresponding lung segment indicate an occlusive PE. Future studies have to investigate if DECT of lung perfusion might also play a role in the assessment of lung diseases such as emphysema, cystic fibrosis or interstitial lung disease. Dedicated scan and contrast material injection protocols for DECT of lung perfusion as well as post-processing techniques are provided in this chapter. Possible pitfalls in data interpretation are discussed.
KeywordsInterstitial Lung Disease Perfusion Defect Lung Parenchyma Lung Perfusion Pulmonary Perfusion
- Chae EJ, Seo JB, Jang YM et al (2010) Dual-energy CT for assessment of the severity of acute pulmonary embolism: pulmonary perfusion defect score compared with CT angiographic obstruction score and right ventricular/left ventricular diameter ratio. AJR Am J Roentgenol 194:604–610PubMedCrossRefGoogle Scholar
- Ferda J, Ferdova E, Mirka H et al (2009) Pulmonary imaging using dual-energy CT, a role of the assessment of iodine and air distribution. Eur J Radiol [Epup ahead of print]Google Scholar
- Fink C, Johnson TR, Michaely HJ et al (2008) Dual-energy CT angiography of the lung in patients with suspected pulmonary embolism: initial results. RofoGoogle Scholar
- Krissak R, Henzler T, Reichert M, Krauss B, Schoenberg SO, Fink C (2010) Enhanced visualization of lung vessels for diagnosis of pulmonary embolism using dual energy CT angiography. Invest Radiol 45:341–346Google Scholar