ORIGINAL PAPER 99 mTc-MIBI washout as a complementary factor in the evaluation of idiopathic dilated cardiomyopathy (IDCM) using myocardial perfusion imaging Mohammad Kazem Shiroodi • Babak Shafiei • Nastaran Baharfard • Mohammad Esmail Gheidari • Babak Nazari • Elaheh Pirayesh • Ali Kiasat • Samaneh Hoseinzadeh • Abolghassem Hashemi • Mohammad Ali Akbarzadeh • Hamid Javadi • Iraj Nabipour • Majid Assadi Received: 26 September 2010 / Accepted: 8 December 2010 Ó Springer Science+Business Media, B.V. 2010 Abstract Rapid technetium-99 m methoxyisobutyli- sonitrile (99 mTc-MIBI) washout has been shown to occur in impaired myocardia. This study is based on the hypothesis that scintigraphy can be applied to calculate the myocardial 99 mTc-MIBI washout rate (WR) to diagnose and evaluate heart failure severity and other left ventricular functional parameters specifically in idiopathic dilated cardiomyopathy (IDCM) patients. Patients with IDCMP (n = 17; 52.65 ± 11.47 years) and normal subjects (n = 6; 49.67 ± 10.15 years) were intravenously administered 99 mTc-hexakis-2-methox- yisobutylisonitrile (99 mTc-MIBI). Next, early and delayed planar data were acquired (at 3.5-h intervals), and electrocardiogram (ECG)-gated myocardial perfu- sion single photon emission computed tomography (SPECT) was performed. The 99 mTc-MIBI WR was calculated using early and delayed planar images. Left ventricular functional parameters were also ana- lyzed using quantitative gated SPECT (QGS) data. In target group, myocardial WRs (29.13 ± 6.68%) were significantly higher than those of control subjects (14.17 ± 3.31%; P \ 0.001). The 99 mTc-MIBI WR increased with the increasing severity of the NYHA functional class (23.16 ± 1.72% for class I, 30.25 ± 0.95% for class II, 32.60 ± 6.73% for class III, and 37.50 ± 7.77% for class IV; P = 0.02). The WR was positively correlated with the end-diastolic volume (EDV) index (r 2 = 0.216; b = 0.464; P = 0.02 [ml/m 2 ], the end-systolic volume (ESV) index (r 2 = 0.234; b = 0.484; P = 0.01 [ml/m 2 ]), the summed motion score (SMS) (r 2 = 0.544; b = 0.738; P = 0.00), and the summed thickening score (STS) (r 2 = 0.656; b = 0.810; P = 0.00); it was negatively correlated with the left ventricular ejection fraction (LVEF) (r 2 = 0.679; b = –0.824; P = 0.00). It can be concluded that 99 mTc-MIBI scintigraphy might be a valuable molecular imaging tool for the diagnosis and evaluation of myocardial damage or dysfunction severity. M. K. Shiroodi  B. Shafiei  N. Baharfard  B. Nazari  E. Pirayesh  A. Kiasat  S. Hoseinzadeh Department of Nuclear Medicine, Taleghani Hospital, Shaheed Beheshti University of Medical Sciences, Tehran, Iran M. E. Gheidari  A. Hashemi  M. A. Akbarzadeh Department of Cardiology, Taleghani Hospital, Shaheed Beheshti University of Medical Sciences, Tehran, Iran H. Javadi Golestan Research Center of Gastroenterology and Hepatology (GRCGH), Golestan University of Medical Sciences, Gorgan, Iran I. Nabipour  M. Assadi The Persian Gulf Nuclear Medicine Research Center, Bushehr University of Medical Sciences, Bushehr, Iran M. Assadi (&) The Persian Gulf Nuclear Medicine Research Center, Bushehr University of Medical Sciences, Moallem Street, 75146-33191 Bushehr, Iran e-mail: assadipoya@yahoo.com; asadi@bpums.ac.ir 123 Int J Cardiovasc Imaging DOI 10.1007/s10554-010-9770-5