Using perfusion CT to evaluate blood supply of pulmonary metastases in vivo

Objective: Using perfusion CT to evaluate blood supply of pulmonary metastases in vivo. Methods: Nineteen patients were enrolled in this study according to inclusive criteria. Selective bronchial arterial catheterization and superselective pulmonary arterial catheterization were carried out simultaneously in each patient under digital subtraction angiography (DSA) guidance before CT scan, respectively. And then patients were moved to multi-slice spiral CT (MSCT) scanner. During breathhold, single location dynamic CT sequences were performed to acquire contrast enhancement imaging in pulmonary metastasis at a rate of 1.5 mL/s and total amount of 6-8 ml contrast medium by bronchial arterial catheter infusion firstly, then ten minutes later at a rate of 3 ml/s and total amount of 40 ml contrast material through pulmonary arterial catheter infusion. Density-time curves were evaluated from three different regions of interest (ROI) in each patient: a large ROI comprising the whole tumor area and two smaller ROIs placed over the area with the highest and lowest enhancement, respectively. Perfusion and peak enhancement index (PEI) were calculated using perfusion CT software retrieved from MSCT instrument in each patient, and the largest diameter was measured through axial CT images. Results: Values of Perfusion of metastasis through pulmonary arterial enhancement was significantly higher than that through bronchial arterial enhancement 133.70 (29.00-346.75) vs 2.30 (0-24.25) ml·min^-1·ml^-1. There was significant difference in PEI between pulmonary arterial enhancement and bronchial arterial enhancement 100.00 (20.75-428.60) vs 11.30 (1.05-26.00) HU as well. Values of perfusion and PEI measured from the three ROIs through pulmonary enhancement were significantly larger than those obtained through bronchial artery enhancement, respectively (P<0.05). Perfusion was not correlated with tumor diameter under the two different enhancement patterns (P>0.05). The correlation coefficients were -0.167 and 0.104, respectively. Otherwise, PEI of metastasis was correlated with tumor diameters simultaneously by the two different enhancement means (P<0.05). The correlation coefficients were 0.421 and 0.405 respectively. Conclusion: Blood supply of pulmonary metastases mostly originated from pulmonary artery, bronchial artery might partially participate in the blood supply to pulmonary metastases at the same time. Pulmonary arterial and bronchial arterial blood supply would be increasing with the metastasis growth. Perfusion CT has played vital role in evaluation of angiogenesis in pulmonary metastases in vivo. (authors)