Evaluation of myocardial perfusion and function by gated single-photon emission computed tomography technetium-99m methoxyisobutylisonitrile in children and adolescents with severe congenital heart disease

Abstract

OBJECTIVES: The value of gated single-photon emission computed tomography technetium-99m methoxyisobutylisonitrile (gated SPECT99m Tc-MIBI) in children is not yet established probably because gated SPECT99m Tc-MIBI has rarely been used in pediatric clinical and research studies. The purpose of this study was to evaluate perfusion abnormalities and left ventricular (LV) function by gated SPECT99m Tc-MIBI in children and adolescents with severe congenital heart disease (CHD). METHODS: Seventeen children and adolescents with severe CHD (11 boys and six girls, mean age 11±4 years) underwent 2-day rest-stress (11 boys) or 1-day rest (six girls) gated SPECT99m Tc-MIBI. Myocardial perfusion was evaluated by a 17-segment model with a 5-point score to derive the summed stress score, the summed rest score (SRS), and the summed difference score based on the 4D-MSPECT software results. The extent of myocardial perfusion abnormalities was also expressed as a percentage of the LV size. The 4D-MSPECT software was used to calculate LV end-diastolic volume, end-systolic volume (ESV), and ejection fraction (EF). RESULTS: Reversible myocardial perfusion defect was found in 7 of 11 children (64%) who underwent rest-stress gated SPECT99m Tc-MIBI. The LV segments involved were anterior, anteroseptal, anterolateral, apical and inferior. These seven children showed significantly larger perfusion abnormalities on stress compared with rest study (18±5 vs. 7±4%, P<0.01) and higher summed stress score compared to SRS (11±4 vs. 4±2, P<0.01). Children and adolescents with myocardial ischemia had significantly lower poststress EF than rest EF (53±12 vs. 59±11%, P<0.05) and significantly higher poststress ESV than rest ESV (81±24 vs. 61±25ml,P<0.05). In six children evaluated only at rest, perfusion defects involved anterior, anteroseptal and apical, or inferolateral segments, accounting for 31±12% of LV and with SRS of 12±5. Their global LV parameters were: end-diastolic volume 118±23ml, ESV 56±16ml, EF 51±10%. CONCLUSION: Poststress and rest-gated SPECT99m Tc-MIBI results indicate that children and adolescents with severe CHD show a range of abnormalities in myocardial perfusion and LV function, which is useful for determining functional importance of morphological malformations. Thus, gated SPECT99m Tc-MIBI provides complementary information that may guide clinical decision making in children and adolescents with severe CHD. © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins.