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. Methods: 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 (TcPO 2 ), ankle-brachial index, intravenous 99m Tc-tetrofosmin perfusion scintigraphy ( 99m Tc-TF), and intraaortic 99m Tc-MAA. Results: Four weeks after BMCI, TcPO 2 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 5 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 5 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 5 0.04) and 99m Tc-MAA count (1.49 ± 3.64 to 5.59 ± 4.84 count ratio/pixel, P 5 0.03) in the foot remained significant. 99m Tc-MAA indicated that the newly developed arteries were approximately 25 μm in diameter. Conclusion: 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.

Preparation of Heat-Denatured Macroaggregated Albumin for Biomedical Applications Using a Microfluidics Platform

“…M2A2 particles from our chip were consistently larger than 99m Tc-MAA used in the clinic (32.7 ± 17.8 μm) but significantly less polydisperse as determined using an F-test (p < 0.05). 21 Histograms of M2A2 prepared at different flow rates and 99m Tc-MAA are shown in Figure 3. Corresponding light micrographs of M2A2 are shown in Figure S2, and representative scanning electron microscopy (SEM) images are in Figure S3.…”

“…The size distribution for clinical-grade 99m Tc-MAA is shown for comparison purposes (adapted from Takagi et al originally published in J. Nuc.Med. with permission from SNMMI21 ). Data is presented as a histogram (5 μm bin width) fitted with a Gaussian curve (R > 0.97 for all M2A2 particle sizes).…”

Feasibility of Hybrid 67Gallium-Citrate SPECT/CT Fusion Imaging for Identifying Patients with Osteomyelitis Awaiting Ostectomy

“…3-C). Regarding the radiographic reliability of the TBR assessment, the linear weighted κ values indicated a moderate interobserver agreement of 0.71 and an intraobserver agreement of 0.67, based on previous ndings [13]. A multivariate regression analysis was performed using the incidence of bone resection as a dependent variable.…”

Radiotracer Imaging Allows for Noninvasive Detection and Quantification of Abnormalities in Angiosome Foot Perfusion in Diabetic Patients With Critical Limb Ischemia and Nonhealing Wounds

“… 17 However, PAD-focused research in the past decade has begun to use the 99m Tc-labeled perfusion tracers 99m Tc-tetrofosmin and 99m Tc-sestamibi, which has reduced radiation exposure to patients, increased image quality on gamma cameras, and demonstrated clinical utility in the detection of PAD within the calf, 28 , 29 as well as assisted with tracking the response to cell therapy in the foot. 30 – 32 Additionally, recent preclinical research has established and validated methods for assessing serial changes in microvascular perfusion within specific lower extremity muscle groups using SPECT/CT imaging. 23 The present study represents the next step in translation of this SPECT/CT perfusion imaging approach into a DM patient population at high risk for lower extremity amputation.…”