Purpose or Case Report: Dual-energy computed tomography (DECT) decomposition software has expanded the scope of CT post-processing. It is an efficient method in pediatric thoracic imaging to define both vascular and parenchymal abnormalities.
Methods & Materials: There are 5 basic material decomposition tools: virtual nonenhanced (iodine subtracted from the image), iodine overlay (iodine image superimposed on the gray-scale image), lung vessel, lung perfusion and automated bone removal images. The lung software, generates pulmonary vessel images by color-coding their iodine amounts, which serves as an indicator of flow. Pulmonary vessels with high flow are color-coded blue and those with slower flow are color-coded red. The software generates so-called perfused blood volume images by analyzing the iodine content in the lung parenchyma, allowing assessment of hypoperfusion. The automated bone removal software for CT angiography subtracts iodine from bone based on differences in their atomic numbers. This poster is based on experience with approximately 400 chest CT scans done on 2^nd and 3^rd generation dual-source systems.
Results: Virtual nonenhanced images play a role in lesion characterization by facilitating detection of small foci of calcification, fat and blood. Iodine overlay images allow for qualitative and quantitative assessments of iodine content, helping in characterizing masses and monitoring treatment response, such as in lymphoma and neuroblastoma, Demonstration of low iodine concentrations (< 1 mg.ml) support the diagnosis of a benign solid mass whereas demonstration of higher iodine concentrations increases concern for malignancy. In thromboembolic disease, absent or hypoplastic pulmonary arteries and pulmonary hypertension, DECT lung vessel images facilitate detection of flow in small subsegmental vessels, which can be difficult in small children. In the same diseases, DECT perfusion images increase sensitivity of detecting perfusion defects based on reduction in iodine content. The bone removal software improves evaluation of coarctation and vascular rings by improving vessel cutoff. This poster will display a wide variety of pathologies to illustrate the material decomposition tools.
Conclusions: The proposed session will demonstrate the latest generation DECT material technology. Material decomposition has increased the robustness of CT in imaging of lung perfusion and lung vessels, characterization of masses, assessment of tumor response to treatment, and vessel evaluation.