New method for accurate estimations of LV
function for small hearts
Keiichiro Magota, PhD,
and Nagara Tamaki, MD, PhD
Hokkaido University Hospital, Sapporo, Japan
Department of Nuclear Medicine, Hokkaido University, Sapporo, Japan
Received May 13, 2016; accepted May 13, 2016
See related article, pp. 1378–1388
Electrocardiography (ECG)-gated myocardial per-
fusion single-photon emission computerized tomography
(SPECT) has played an important role in assessments of
myocardial perfusion and function.
provide important information about patients’ prognoses
and treatment effects in various cardiovascular diseases.
Various functional parameters including the left ventric-
ular (LV) volume and left ventricular ejection fraction
(LVEF) have been well validated.
However, there are
some limitations regarding the quantiﬁcation of the LVEF
by gated myocardial perfusion SPECT. Each functional
parameter may vary depending on the SPECT recon-
struction methods, reconstruction ﬁlters, and software
The relatively low spatial resolution of
nuclear cardiology images may make it difﬁcult to visu-
alize small objects, such as the LV cavity of a small
ventricle, particularly at end-systolic phase. Conse-
quently, the left ventricular end-systolic volume
(LVESV) is underestimated and the LVEF is
The authors’ group recently introduced a volume-
dependent edge correction algorithm that is used to
reduce the errors in ESV and EF estimations of small
The present study extended this software
application for gated myocardial perfusion SPECT in
pediatric patients (The present study). The study group
consisted of 66 pediatric patients (ages 6-15 years with
the mean age of 11.9 years) in whom either malignant
bone or soft-tissue tumors were histologically diag-
nosed. The volume and LVEF calculations based on
echocardiography were used as a gold standard.
Although the LVEF was signiﬁcantly higher when
obtained using quantitative gated SPECT-ﬁltered back
projection (QGS-FBP) without resolution correction
compared to the results obtained by an echo study, no
signiﬁcant differences in the LVEF were seen between
the results from the cardioREPO-OSEM (ordered subset
expectation-maximization) with resolution correction
(RC) and those from the echo study. Thus, they con-
cluded that the small heart effect may be minimized for
LV functional analyses when the OSEM algorithm was
used with RC with the cardioREPO algorithm.
The present ﬁndings supported the previous results
obtained by both a phantom study and clinical applica-
tions for pediatric patients. The accurate estimation of
LV function is of clinical importance particularly for
pediatric patients with a malignancy who may require
repetitive cardiotoxic chemotherapy.
function is accurately estimated with this new method,
gated perfusion SPECT has potential for monitoring LV
function. In addition, this new method using the car-
dioREPO-OSEM algorithm with resolution correction
provided high-quality myocardial perfusion images that
may provide a better delineation of endocardial borders
for LV volume calculation.
One may argue whether gated perfusion studies can
replace gated blood pool studies. Since a gated
myocardial perfusion study may provide both perfusion
and functional information with an accurate estimate of
LV volume and function, the ﬁndings of the study pro-
vide additional important information for monitoring the
cardiac status during chemotherapy for pediatric patients
with malignant diseases.
There are a number of concerns regarding the present
study. First, the gold standard volumes were derived from
the ‘old-fashioned’ M-mode echocardiography, under the
assumption of a spheroid shape. Such a comparison
seems to be rather weak. It would be better to compare
Reprint requests: Nagara Tamaki, MD, PhD, Department of Nuclear
Medicine, Hokkaido University, Sapporo, Japan; natamaki@med.
J Nucl Cardiol 2017;24:1393–94.
Copyright Ó 2016 American Society of Nuclear Cardiology.