Room: Track 1
Purpose: validate a two-volume dynamic CT renal perfusion technique in a swine animal model using fluorescent microspheres as the reference standard.
Methods: swine (55 ± 24 kg) underwent dynamic CT perfusion (CTP) of the kidneys using a 320-slice scanner at 100 kV and 200mA for 20-30 seconds. An angioplasty balloon was inserted in the right renal artery of each swine under fluoroscopic guidance to induce several levels of stenosis. Multiple contrast injections (1.0 ml/kg of contrast followed by 0.5 ml/kg of saline chaser at 5.0 ml/sec) were made resulting in a total of 18 CTP acquisitions. Reference fluorescence microspheres were injected during each CTP acquisition as the reference standard. For each acquisition, a semi-automatic segmentation of the renal artery was used to generate the entire arterial input function (AIF), but only two volume scans were systematically selected for dynamic CT perfusion measurement. Specifically, the first volume was selected at the base of the AIF, while the second volume was selected at or near the peak of the AIF. The two-volume dynamic CT perfusion measurements were then compared to the reference standard microsphere perfusion measurements through regression analysis. The CTDIvol32 and size-specific dose estimate (SSDE) of the two-volume perfusion measurement were also calculated.
Results: two-volume dynamic CT perfusion measurements (P_FPA) were in good agreement with the reference standard microsphere perfusion measurements (P_REF) by P_FPA= 1.04P_REF – 0.08 (r=0.65) with a root-mean-square-error of 0.32ml/min/g and a root-mean-square-deviation of 0.35ml/min/g. The CTDIvol32 and SSDE for the two-volume perfusion measurement were 39.0 and 66.4mGy, respectively.
Conclusion: two-volume dynamic CT perfusion technique can provide accurate renal perfusion measurements at a low-radiation dose.