Imaging Angiogenesis Using 99mTc-Macroaggregated Albumin Scintigraphy in Patients with Peripheral Artery Disease.

Abstract

One problem of vascular angiogenesis therapy is the lack of reliable methods for evaluating blood flow in the microcirculation. We aimed to assess whether (99m)Tc-macroaggregated albumin perfusion scintigraphy ((99m)Tc-MAA) predicts quantitated blood flow after therapeutic angiogenesis in patients with peripheral artery disease. Forty-six patients with peripheral artery disease were treated with bone marrow mononuclear cell implantation (BMCI). Before and 4 wk after BMCI, blood flow was evaluated via transcutaneous oxygen tension (TcPO2), ankle-brachial index, intravenous (99m)Tc-tetrofosmin perfusion scintigraphy ((99m)Tc-TF), and intraaortic (99m)Tc-MAA. Four weeks after BMCI, TcPO2 improved significantly (20.4 ± 14.4 to 36.0 ± 20.0 mm Hg, P < 0.01), but ankle-brachial index did not (0.65 ± 0.30 to 0.76 ± 0.24, P = 0.07). Improvement in (99m)Tc-TF count (0.60 ± 0.23 to 0.77 ± 0.29 count ratio/pixel, P < 0.01) and (99m)Tc-MAA count (5.21 ± 3.56 to 10.33 ± 7.18 count ratio/pixel, P = 0.02) was observed in the foot region but not the lower limb region, using both methods. When these data were normalized by subtracting the pixel count of the untreated side, the improvements in (99m)Tc-TF count (-0.04 ± 0.26 to 0.08 ± 0.32 count ratio/pixel, P = 0.04) and (99m)Tc-MAA count (1.49 ± 3.64 to 5.59 ± 4.84 count ratio/pixel, P = 0.03) in the foot remained significant. (99m)Tc-MAA indicated that the newly developed arteries were approximately 25 μm in diameter. BMCI induced angiogenesis in the foot, which was detected using (99m)Tc-TF and (99m)Tc-MAA. (99m)Tc-MAA is a useful method to quantitate blood flow, estimate vascular size, and evaluate flow distribution after therapeutic angiogenesis.