Preliminary clinical investigation of 99mTc-methoxyisobutylisonitrile washout rate in hypertrophic cardiomyopathy.
OBJECTIVE
The aim of this study was to investigate the changes in early and late washout rates of 99mTc-methoxyisobutylisonitrile (MIBI) in hypertrophic cardiomyopathy (HCM), and to analyze the relationships between early and late washout rates and the hypertrophic thickness of left ventricular (LV) wall.


METHODS
The patients who were clinically diagnosed as positive for HCM underwent 99mTc-MIBI static planar and gated single-photon emission computed tomography (SPECT) imaging. Early (90 min after the intravenous injection) and late (4 h after the intravenous injection) washout rates of 99mTc-MIBI between HCM group and normal control group were compared. Linear correlation analysis was made between early and late washout rates and the hypertrophic thickness of LV wall measured by gated SPECT.


RESULTS
The early and late washout rates of 99mTc-MIBI in normal control group were (18.90+/-3.70) and (31.27+/-4.04)%, respectively; and the washout rates in HCM group were (27.77+/-2.60) and (42.66+/-3.30)%, respectively. Significant statistical differences were observed in the early and late washout rates of 99mTc-MIBI between HCM group and normal control group (t=-7.320 and t=-8.069, both P<0.01). Correlations between early and late washout rates and the maximal hypertrophic thickness of LV wall obtained by gated SPECT were excellent (r=0.611, P<0.05; r=0.873, P<0.01, respectively).


CONCLUSIONS
The early and late washout rates of 99mTc-MIBI in HCM group were significantly higher than those in normal control group, and both the early and late washout rates correlated well with the hypertrophic thickness of LV wall.
Sun
Muchuan
M
Nuclear Medicine Department, the No. 1 Hospital of China Medical University, Shenyang, Liaoning, China.
Li
Yaming
Y
Li
Na
N
Liu
Hao
H
Yin
Yafu
Y
Li
Deshun
D