Room: Exhibit Hall | Forum 9
Purpose: To investigate the spatial and temporal behavior of iodine uptake in the lungs of porcine subjects.
Methods: Five Wisconsin Miniature Swineâ„¢ (WMS) were scanned multiple times (N=23 scans) on a Siemens SOMATOM Definition Edge CT scanner using the Dynamic 4D acquisition technique, which allows for perfusion analysis. A 15 cm axial length was scanned in the subjectsâ€™ lungs as 80 ml of iodine contrast was injected at a rate of 5 ml/sec. The acquisition consisted of repeated scanning of the same volume at 1.5 sec intervals for 45 seconds and then every 4.5 seconds until the contrast had washed out of the lung. The resulting images were analyzed in the Syngo.via software. Six ROIs were placed in each lung spanning the anterior-posterior extent of the lungs, while avoiding large vessels. The HU as a function of time was then recorded and analyzed in each ROI.
Results: On average, the most posterior ROIs showed the largest increase in HU during the perfusion scan (mean âˆ†HU=92.0ï‚±17.5), while the most anterior ROIs showed negligible HU increases (mean âˆ†HU=13.0ï‚±7.27) The posterior ROIs also showed the quickest uptake of contrast material. On average, the most posterior ROIs reached their maximum HU 6.39ï‚±3.02 seconds quicker than the most anterior ROI that exhibited iodine uptake.
Conclusion: The lungs of the WMS exhibited more perfusion in posterior regions of the lung compared to more anterior regions (p<0.0001). These posterior regions also showed a quicker uptake of the contrast material (p<0.0001). This is important consider when performing contrast CT scans in the lungs as the timing of the scan relative to contrast injection can be optimized based on which part of the lung is of interest. This serves as baseline of lung perfusion in WMS as part of an investigation into radiation induced changes in perfusion following radiotherapy.