Quantitative Iodine-Based Material Decomposition Images In Spectral CT:a Pilot Study To Evaluate The Change Of Fractional Blood Flow With Lung Cancer

Objective To evaluate the change of fractional blood distribution in patients with lung cancer and analyze the normal blood distribution of healthy side using iodine-based material decomposition images in Spectral CT imagingMaterial and methods thirty-nine patients with lung cancer underwent enhanced CT with spectral imaging mode (fast80/140kVp switching) on a GE Discovery CT750HD scanner to generate Iodine-based material decomposition images. On the iodine-based images, the iodine distribution in the lung parenchyma was used to identify the defects or decrease for blood perfusion by comparing the iodine density on the tumor side and the contralateral and healthy side. Measure the iodine density on the iodine-based maps in different regions.27ROIs were located at each unilateral lung: from the apex to the base, the lung were equally divided into nine layers and to place ROI; from ventral to dorsal side, ROI was located at ventral part, central part and dorsal part. And use a dual threshold (-500and-910HU) on conventional CT (lung window) images to extract lung volume without emphysema or atelectasis.Results The iodine-based maps, displayed different degrees of perfusion defects or decreased perfusion for all39patients. There was a significant difference for the iodine-density between tumor side (7.95±0.18mg/cc) and the healthy side (10.31±0.18mg/cc)(P<0.05); there was a significant difference for iodine-density between defect (or decreased) part (3.75±0.24mg/cc) and the same part on the unaffected side(11.52±0.35mg/cc)(P<0.05); there was no significant difference for the value between unaffected side (9.94±0.24mg/cc) and the normal lung parenchyma on the tumor side (9.59±0.29mg/cc)(P<0.05).Conclusions Spectral CT imaging is an alternative method to show the distribution of pulmonary blood flow and indirectly evaluate the fractional function. It is an important method to get useful information of the parenchyma perfusion around tumor. We proposed that the iodine-based map is a valuable way to guide the therapy of lung cancer.