Assessment of renal hemodynamics and function in pigs with 64-section multidetector CT: comparison with electron-beam CT.

PURPOSE: To prospectively evaluate the feasibility of obtaining reliable measurements of renal hemodynamics and function by using 64-section multidetector CT.
MATERIALS AND METHODS: This study was approved by the Institutional Animal Care and Use Committee. Eight pigs (two with induced unilateral renal artery stenosis) were studied with both electron-beam CT and 64-section multidetector CT at 1-week intervals in randomized order. Both kidneys were scanned repeatedly, without table movement, for about 3 minutes after intravenous (IV) administration of a bolus of contrast medium and again during vasodilator challenge (acetylcholine). Images were reconstructed on each CT console but were analyzed on the same independent workstation. Attenuation changes in the kidneys were plotted as function of time, and time-attenuation curves (TACs) were subsequently analyzed to determine regional perfusion and volume, glomerular filtration rate (GFR), and renal blood flow (RBF). Statistical analysis utilized Student t test, analysis of variance (ANOVA), linear regression, and Bland-Altman analysis.
RESULTS: TACs obtained with multidetector CT were qualitatively similar to those obtained with electron-beam CT, as were the quantitative values of renal perfusion and function. RBF correlated significantly between the two techniques (RBF(MD) = 0.96 . RBF(EB) mL/min; R = 0.77, P < .01). GFR(MD) was also similar to GFR(EB) (77.6 +/- 8.3 vs 79.8 +/- 8.8 mL/min, p > .05). Bland-Altman plots showed good agreement between the two techniques. Both techniques similarly detected the differences between stenotic and contralateral kidneys.
CONCLUSION: The clinical multidetector CT scanner provides reliable measurements of single-kidney hemodynamics and function, which are similar to those obtained with previously validated electron-beam CT.