Takahiro Higuchi1,2,3, Rudolf A Werner4,5,6. 1. Department of Nuclear Medicine, University Hospital Würzburg, Oberdürrbacher Str. 6, 97080, Würzburg, Germany. 2. Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Okayama, Japan. 3. Comprehensive Heart Failure Center, University Hospital Würzburg, Würzburg, Germany. 4. Department of Nuclear Medicine, University Hospital Würzburg, Oberdürrbacher Str. 6, 97080, Würzburg, Germany. rudolfwerner2015@gmail.com. 5. Comprehensive Heart Failure Center, University Hospital Würzburg, Würzburg, Germany. rudolfwerner2015@gmail.com. 6. The Russell H Morgan Department of Radiology and Radiological Sciences, Division of Nuclear Medicine and Molecular Imaging, Johns Hopkins School of Medicine, Baltimore, MD, USA. rudolfwerner2015@gmail.com.