|ECR 2019 / C-3047|
|The utility of dual energy CT in diagnosis of amiodarone induced lung disease: a prospective cohort study|
Aims and objectives
Amiodarone is an iodinated benzofuran derivative, class III antiarrhythmic agent used to suppress tachyarrhythmias. Pulmonary toxicity is among the most serious adverse effects of amiodarone. The diagnosis of amiodarone induced lung injury (AILD) is made by excluding alternative diagnoses and makes use of CT imaging. Since amiodarone is an iodine-containing compound, lung parenchymal lesions that show high attenuation on CT are helpful in suggesting AILD.
However, dual-energy CT (DECT) is particularly sensitive for the detection of iodine due to its high atomic number. Furthermore, in addition to the standard CT images, dedicated software creates overlay of the low energy images, in which iodine content in tissues can be better appreciated and amount of iodine better quantified. Consequently, DECT may represent a more sensitive method for detection of AILD.
The purpose of the present research was to evaluate the correlation between the diagnoses of AILD by DECT based on amiodarone iodine deposition and the clinical diagnosis of AILD.
Several forms of pulmonary disease occur among patients treated with amiodarone, including interstitial pneumonitis, organizing pneumonia, acute respiratory distress syndrome, diffuse alveolar hemorrhage, pulmonary nodules and solitary masses, and rarely pleural effusion.
Presently, there is no gold standard method for the diagnosis of AILD which is usually made by exclusion. Amiodarone lung toxicity on high resolution CT manifests most commonly as diffuse interstitial thickening or ground glass opacities. Furthermore, since amiodarone is an iodine-containing compound, parenchymal lesions often show high attenuation, a finding that is helpful in suggesting AILD.
DECT is a relatively newly implemented technology in CT, capable of material decomposition, allowing to better delineate chemical composition of structures and to differentiate them based on the different energy absorption. DECT is particularly sensitive for the detection of iodine which exhibits increased absorption of the low energy level photons. In DECT, in addition to standard CT images (composed of the mixed high and low energy images) complementary sets of low and high energy images are acquired, without increasing radiation dose. Dedicated software creates overlay of the low and high energy images, allowing for better detection and quantification of iodine.
We suggest that the low energy images and iodine maps can be used to detect amiodarone deposition in lungs utilizing non-enhanced CT exams.
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