Sang-Keun Woo1, Byung Seok Moon2, Bom Sahn Kim3, Min Hwan Kim1, Yong Jin Lee1, Jae Ho Jung2, Kyo Chul Lee1, Youngho Seo4, Wook Kim1, Sang Moo Lim1, Byung Chul Lee5, Sang Eun Kim6. 1. Division of RI-Convergence Research, Korea Institute of Radiological and Medical Sciences, Seoul 01812, Republic of Korea. 2. Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam 13620, Republic of Korea. 3. Department of Nuclear Medicine, Ewha Womans University School of Medicine, Seoul 07985, Republic of Korea. 4. Department of Radiology, University of California San Francisco School of Medicine, San Francisco, CA 94143, USA. 5. Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam 13620, Republic of Korea; Center for Nanomolecular Imaging and Innovative Drug Development, Advanced Institutes of Convergence Technology, Suwon 16229, Republic of Korea. Electronic address: leebc@snu.ac.kr. 6. Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam 13620, Republic of Korea; Center for Nanomolecular Imaging and Innovative Drug Development, Advanced Institutes of Convergence Technology, Suwon 16229, Republic of Korea; Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 08826, Republic of Korea.
Abstract
INTRODUCTION: Global and regional sympathetic activity in the heart can be evaluated using [123I]meta-iodobenzylguanidine ([123I]mIBG) imaging. However, [123I]mIBG is associated with low image spatial resolution and sensitivity in cardiac imaging. We investigated the capability of an F-18-labeled mIBG derivative, meta-(3-[18F]fluoropropyl)benzylguanidine ([18F]mFPBG), for identifying ischemic and viable myocardium in a rat model of myocardial infarction. MATERIALS AND METHODS: The ex vivo biodistribution and in vivo metabolic stability of [18F]mFPBG were investigated in Sprague-Dawley rats. Selective cardiac adrenergic activation was confirmed via a blocking experiment involving pretreatment with desipramine (2 mg kg-1), followed by the administration of [18F]mFPBG. Imaging properties of [18F]mFPBG were compared with those of traditional cardiac imaging radiotracers ([123I]mIBG and [99mTc]MIBI) in a rat model of myocardial infarction. Non-invasive image-based measurements of infarct sizes were then compared with histological findings by using Bland-Altman analysis. RESULTS: The differences in infarct sizes determined using histological analysis and [18F]mFPBG PET were -2.55 ± 4.99% (range: -12.33 to 7.22), -2.35 ± 3.32% (range: -8.87 to 4.16), and -3.15 ± 6.16% (range: -15.24 to 8.93) at 5, 20, and 40 min, respectively. Furthermore, [18F]mFPBG PET was superior to traditional imaging methods in assessing the degree of ischemia in areas of myocardial infarction, as well as the actual infarct size. CONCLUSION: Compared to [123I]mIBG, [18F]mFPBG showed improved spatial resolution and sensitivity in a rat model of myocardial infarction. This result suggested that [18F]mFPBG is a promising cardiac PET imaging agent for potential diagnostic application in PET cardiology.
INTRODUCTION: Global and regional sympathetic activity in the heart can be evaluated using [123I]meta-iodobenzylguanidine ([123I]mIBG) imaging. However, [123I]mIBG is associated with low image spatial resolution and sensitivity in cardiac imaging. We investigated the capability of an F-18-labeled mIBG derivative, meta-(3-[18F]fluoropropyl)benzylguanidine ([18F]mFPBG), for identifying ischemic and viable myocardium in a rat model of myocardial infarction. MATERIALS AND METHODS: The ex vivo biodistribution and in vivo metabolic stability of [18F]mFPBG were investigated in Sprague-Dawley rats. Selective cardiac adrenergic activation was confirmed via a blocking experiment involving pretreatment with desipramine (2 mg kg-1), followed by the administration of [18F]mFPBG. Imaging properties of [18F]mFPBG were compared with those of traditional cardiac imaging radiotracers ([123I]mIBG and [99mTc]MIBI) in a rat model of myocardial infarction. Non-invasive image-based measurements of infarct sizes were then compared with histological findings by using Bland-Altman analysis. RESULTS: The differences in infarct sizes determined using histological analysis and [18F]mFPBG PET were -2.55 ± 4.99% (range: -12.33 to 7.22), -2.35 ± 3.32% (range: -8.87 to 4.16), and -3.15 ± 6.16% (range: -15.24 to 8.93) at 5, 20, and 40 min, respectively. Furthermore, [18F]mFPBG PET was superior to traditional imaging methods in assessing the degree of ischemia in areas of myocardial infarction, as well as the actual infarct size. CONCLUSION: Compared to [123I]mIBG, [18F]mFPBG showed improved spatial resolution and sensitivity in a rat model of myocardial infarction. This result suggested that [18F]mFPBG is a promising cardiac PET imaging agent for potential diagnostic application in PET cardiology.