Noninvasive determination of arterial input function using fuzzy clustering for quantification of myocardial blood flow with nitrogen-13-ammonia and PET: comparison with factor analysis and independent component analysis. - T. Kitada; Kenya Murase; Y. Nishimura; Youichi Yamazaki; Masaaki Shinohara; S. Iwamoto; Y. Ueno; Sotoshi Yamada; J. Yoshioka; D. Nakatani (CARS, 2001)