1. Journal of Nuclear Cardiology | Official Journal of the American Society of Nuclear Cardiology
Reducing the small-heart effect in pediatric gated myocardial perfusion single-photon emission computed tomography
Hiroto Yoneyama1, Kenichi Nakajima2, Koichi Okuda3,
Shinro Matsuo2, Masahisa Onoguchi4, Seigo Kinuya2, Lars Edenbrandt5
1 Department of Radiological Technology, Kanazawa University Hospital, Japan
2 Department of Nuclear Medicine, Kanazawa University Hospital, Japan
3 Department of Physics, Kanazawa Medical University, Japan
4 Department of Health Science, Graduate School of Medical Science, Kanazawa University, Japan
5 Department of Molecular and Clinical Medicine, University of Gothenburg, Gothenburg, Sweden
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2. Journal of Nuclear Cardiology | Official Journal of the American Society of Nuclear Cardiology
BACKGROUND
1- Although gated myocardial perfusion SPECT has been used to evaluate left ventricular (LV) ejection fraction (EF), EF cannot be evaluated accurately in pediatric patients with a small heart (SH). 2- Recently, it has been reported that cardioREPO software included an algorithm to compensate for the SH effect. 3- Resolution correction (RC) technology has been developed for SPECT reconstruction.
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3. METHODS Study type: Retrospective
Journal of Nuclear Cardiology | Official Journal of the American Society of Nuclear Cardiology
METHODS
Study type: Retrospective
Study subjects: We compared two reconstruction algorisms, filtered back projection (FBP) method without the RC and an iterative method based on an ordered subset expectation maximization (OSEM) algorithm with the RC, and two cardiac functional evaluation software programs, quantitative gated SPECT (QGS) and cardioREPO, in terms of their accuracy for estimating EF of SHs.
Study endpoints:
Effects of reconstruction algorisms and cardiac functional evaluation software programs on SPECT images were studied using SH phantom.
We compared ESV, EDV and EF of gated myocardial perfusion SPECT to echocardiographic measurement (Echo) in 66 pediatric patients.
Study variables
・Reconstruction algorisms (FBP without RC, OSEM with RC).
・Cardiac functional evaluation software programs (QGS, cardioREPO).
　　　　　 ・Image processing parameters (FWHM of Gaussian filter, pixel size, magnification)
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4. RESULTS Echo ： EDV 47mL ESV 19mL EF 60% QGS - FBP without RC
Journal of Nuclear Cardiology | Official Journal of the American Society of Nuclear Cardiology
RESULTS
Echo ：　EDV 47mL ESV 19mL EF 60%
cardio REPO - FBP without RC
EDV 35mL ESV 12mL EF 65%
QGS - FBP without RC
EDV 17mL ESV 2mL EF 86%
QGS - OSEM with RC
EDV 18mL ESV 3mL EF 83%
cardio REPO - OSEM with RC
EDV 39mL ESV 16mL EF 60%
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5. RESULTS EF measured in patients with ESV ≤20 mL.
Journal of Nuclear Cardiology | Official Journal of the American Society of Nuclear Cardiology
RESULTS
EF measured in patients with ESV ≤20 mL.
n.s.
p=0.0011
p<0.0001
Echo
cardio REPO OSEM with RC
cardio REPO FBP without RC
QGS FBP without RC
QGS OSEM with RC
EF, ejection fraction　(%)
100 80 60 40
QGS FBP without RC ±8.4%
QGS OSEM with RC　　　　　　 ±8.6%
Cardio REPO FBP without RC 72.1±10.0%
Cardio REPO OSEM with RC ±6.1%
Echo ±5.0%
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6. Journal of Nuclear Cardiology | Official Journal of the American Society of Nuclear Cardiology
CONCLUSIONS
1‐Number of SH (ESV < 20mL) was 48 of 66 pediatric patients, and EF was overestimated by the SH effect. 2 - When conventional FBP method without RC and QGS were used, in patients with a very small volume, underestimation of the LV volume is unavoidable. 3 - Even in pediatric patients with SH, the SH effect was significantly reduced when OSEM algorithm with RC and Cardio REPO were used. No significant difference in EF was observed between Echo and cardioREPO-OSEM with RC. 4 - Gated myocardial perfusion SPECT imaging can be applied to pediatric cardiac disease and follow-up studies of chemotherapy as well.
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