Multislice CT angiography in cardiac imaging: prospective ECG-gating or retrospective ECG-gating?
Z Sun, PhD
Discipline of Medical Imaging, Department of Imaging and
Applied Physics, Curtin University of Technology, Perth, Western Australia
With the advent of multislice CT more than a decade ago,
multislice CT angiography has demonstrated a huge potential in the less
invasive imaging of cardiovascular disease, especially in the diagnosis of
coronary artery disease. The diagnostic accuracy of multislice CT angiography
has been significantly augmented with the rapid technical developments ranging
from the initial 4-slice, to the current 64-slice and 256 and 320-slice CT
scanners. This is mainly demonstrated by the improved spatial and temporal
resolution when compared to the earlier type of CT scanners. Traditionally,
multislice CT angiography is acquired with retrospective ECG-gating with
acquisition of volume data at the expense of increased radiation dose, since
data is acquired at the entire cardiac cycle, although not all of them are used
for postprocessing or reconstructions. Recently, there is an increasing trend
of utilising prospective ECG-gating in cardiac imaging with latest multislice
CT scanners (64 or more slices) with significant reduction of radiation dose
when compared to retrospective ECG-gating method. However, there is some debate
as to the diagnostic value of prospective ECG-gating in the diagnosis of
coronary artery disease, despite its attractive ability to reduce radiation
dose. This article will review the performance of retrospective ECG-gating in
the diagnostic value of coronary artery disease, highlight the potential
applications of prospective ECG-gating, and explore the future directions of
multislice CT angiography in cardiac imaging. � 2010 Biomedical Imaging
and Intervention Journal. All rights reserved.
Coronary artery disease (CAD) is the leading cause of
death in western countries. The standard of reference for diagnosis of CAD is
still invasive coronary angiography, with the advantage of high spatial
resolution and temporal resolution. Despite its cost, inconvenience to
patients, and a small but distinct procedure-related morbidity (1.5%) and
mortality (0.2%) rate, more than 1 million invasive diagnostic coronary
angiography procedures are performed annually in the United States alone.
Similarly, CAD is the single most important cause of death in Australia and New Zealand. Every year, billions of dollars have been spent in the treatment of
coronary artery disease ($3.9 billion direct spending in Australia 1993-94 according to Australian Institute of Health and Welfare, 2003). Each year
cardiovascular disease resulted in 81,926 coronary angiography examinations in
Australia 2001-02 (Australia�s Health 2004, AIHW). Given the invasiveness of
coronary angiography and potential danger of having a small risk of serious
complications (arrhythmia, stroke, coronary-artery dissection and death), a
non-invasive technique for imaging of the coronary artery disease is highly
Imaging of the heart and coronary artery branches has
always been technically challenging due to the heart�s continuous movement.
Over the last decade, great strides have been made in the field of cardiac imaging
as non-invasive coronary imaging modalities have undergone rapid developments
[1-4]. Initially, electron-beam CT was found valuable in calcium scoring, but
its application in the diagnosis of CAD was restricted to a greater extent due
to limited spatial resolution . Magnetic resonance imaging shows promising
results as reported in some studies [3, 4], however, the imaging protocols are
variable based on the MR vendor and software availability which prevents it
from being widely used. Imaging of the heart has moved into a new diagnostic
era with the introduction of multislice CT (MSCT) and development of
electrocardiography-synchronised scanning and reconstruction techniques.
Multislice CT represents technical evolution in cardiac
imaging when 4-slice CT scanner was first introduced into the clinical practice
in 1998 . Diagnostic accuracy of multislice CT in CAD has been significantly
improved with the development of scanning techniques, which are demonstrated by
the emergence of 16-, 64-slice and even more recently 256-and 320-slice CT
scanners [6-9]. Until recently, all of the studies were performed with
retrospective ECG-gated cardiac imaging with high diagnostic accuracy for the
detection of CAD at the cost of high radiation dose since images were acquired
during the entire cardiac cycle. Prospective gating with axial non-helical scan
was used a long time ago with electron-beam CT for calcium scoring. However, in
early MSCT of the coronary arteries, the retrospective approach was favoured
(and is still widely regarded) as the method of choice to achieve high image
quality, especially when patient factors are not favourable for optimal image
quality (e.g. arrythmias, high heart rate, etc). The main drawback of the
retrospective approach is the relatively higher dose penalty and this has
brought back into favour the prospective approach.
Recently, prospective ECG-gating was introduced for
cardiac MSCT angiography, and this imaging protocol is increasingly being
reported in the literature, despite sufficient evidence still needed to verify
its diagnostic value. This paper will review the diagnostic accuracy of
retrospective gating CT angiography; the potential applications of prospective
gating cardiac CT angiography, and highlight some future directions of MSCT in
Diagnostic value of retrospective ECG-gated CT angiography in CAD
The feasibility of cardiac MSCT was initially demonstrated
with 4-slice CT using retrospective ECG-gated technique. Volumetric CT data is
acquired throughout the entire cardiac cycle during simultaneous recording of
the ECG signal. Subsequently, data from specific periods of the cardiac cycle
(most commonly at late diastolic phase) is reconstructed by retrospective
referencing to the ECG signal with the aim of generating images with the least
motion artefacts. Over the last decade a great deal of interest has been
focused on imaging and diagnosis of CAD with MSCT due to its less invasive
nature and fast scanning technique with extended z-axis coverage when compared
to single slice CT. Earlier studies with 4-slice CT showed moderate diagnostic
accuracy with pooled sensitivity and specificity of 78% and 93%, respectively
. However, image quality was impaired in many cases with 4-slice CT due to
limited spatial and temporal resolution, and the unassessable segments could be
as high as more than 20% in 4-slice studies . With the introduction of
16-slice CT, image quality in coronary MSCT has become more consistent with
improved results achieved. Studies that used 16-slice CT with acquisition and
rotation times of <400 ms have reported sensitivities between 83% and 98%
and specificities between 96% and 98% [11-14].
Shorter examination times are possible with further
improved diagnostic accuracy with 64-slice CT owing to improved spatial and
temporal resolution compared with 16-slice CT. Acquisition of isotropic volume
data are made available with 64-slice CT, thus detection of main and side
coronary artery branches is improved when compared to earlier types of MSCT
scanners. Several meta-analyses of 64-slice CT studies reported sensitivities
of 93% and specificities of 96% (in 6 studies) , sensitivities of 97% and
specificities of 88% (in 15 studies) , and sensitivities of 86% and
specificities of 96% (in 19 studies) . These studies concluded that MSCT,
especially with 64-or more slice CT, has high diagnostic accuracy for detection
of CAD and could be used as an effective alternative to invasive coronary
angiography in selected patients.
In 2006, the first dual source multislice CT scanner was
introduced . With the coupling of two X-ray tubes mounted at 90� to each
other in a single gantry, the rotation time was shortened, temporal resolution
was doubled (83 ms with dual source CT vs 165 ms with 64-slice CT), and heart
rate dependence was eliminated. Studies performed with dual source CT showed
promising results with high diagnostic accuracy for detection of CAD, and most
importantly the image quality is independent of heart rate [19-21]. Leber et
al.  in their early study reported dual source CT had high diagnostic
accuracy for detection of coronary stenoses and image quality was independent
of heart rate. The benefit of improved temporal resolution with dual source CT
is evident with supporting evidence by later studies further confirming its
improved accuracy, with heart rate having no significant effect on image
quality and diagnostic accuracy [19-22]. Rixe et al. in their recent
study concluded that high diagnostic accuracy (99% and 92% at segment-based and
patient-based analysis, respectively) was achieved even at high heart rates
. Heart-rate independent image quality with dual source CT represents
another milestone in cardiac CT and it could be used as a reliable alternative
to invasive coronary angiography for detection of CAD.
While satisfactory results have been achieved with the
retrospective ECG-gating through continuous exposure in a low-helical pitch
(0.2-0.4) resulting in multiple overlapping regions of X-ray exposure, the
downside is the relatively high effective radiation doses. The radiation dose
associated with retrospective ECG-gating is gradually increased with the
increased number of detector rows and reduction of detector size. Thus, 4-slice
CT scanners have lower dose than 16-slice scanners. Similarly 16-slice scanners
have lower doses than 64-slice, and subsequently doses from 64-slice will be
lower than those acquired with 256 and 320 slice scanners. Therefore, various
strategies have been taken to reduce the radiation dose while using MSCT
angiography in cardiac imaging, and prospective ECG-gating is by far the most
effective and significant technique to reduce radiation dose.
Diagnostic application of prospective ECG-gating CT angiography in CAD
Prospective ECG-gating utilises the same technique as that
used in electron-beam CT which is defined as the step and shoot method. It is
mainly used for quantification of calcium burden, but recently it is
increasingly used for CT coronary angiography examinations. The scan is performed
in a non-helical way with acquisition of a series of axial images instead of
volumetric data. Unlike retrospective gating, prospective ECG-gating or
prospective triggering allows for acquisition of data by selectively turning
the x-ray tube on only in the selected phase, triggered by the ECG signal, and
turning off during the rest of R-R cycle. This is also referred to as
sequential or step-and-shoot acquisition with prospective triggering and the
effective pitch is 1.0. The main advantage of this scanning protocol is the
lower radiation dose as X-ray exposure only takes place during the selected
cardiac phase rather than throughout the entire cardiac cycle. Therefore, a
significant reduction of radiation dose can be expected from prospective
ECG-gating, which is the most attractive side of this scanning protocol
compared to retrospective ECG-gating.
Recent technical developments of MSCT imaging technique
allows for prospective ECG-gating to be performed in a single heart beat with
helical scan [9, 23, 24]. Rybicki in their initial study showed that using
320-slice CT (Toshiba AquilionOne Dynamic Volume CT) prospective ECG-gating
diagnostic images were achieved in more than 90% of patients with reduction of
radiation dose . In addition to reduction of motion artefacts, functional
assessment of the heart can also be achieved with 320-slice CT since the scan
is performed in a single heart beat .
Use of prospective ECG-gating with 64-slice or dual source
CT has been reported to reduce the effective radiation dose by up to 90% when
compared to retrospective ECG-gating technique [25-37]. In 2006, Hsieh et
al.  first described a step-and-shoot prospectively gated protocol for
imaging coronary artery disease. They claimed that patient dose could be reduced
by at least 50% when compared to the standard retrospective gated protocol
without compromising image quality. Afterwards, Husmann et al.  in
their first clinical experience demonstrated the feasibility of prospective
ECG-gating with low dose results. Diagnostic image quality was achieved in 93%
of 41 patients with suspected or proved CAD with very low mean effective dose
of 2.1 mSv (1.1-3.0 mSv), when heart rate was less than 63 bpm. This contrasts
significantly to the higher radiation dose arising from previous
retrospectively gated cardiac MSCT angiography (up to 21 mSv) [27, 28]. It must
be noted that such a high radiation dose results from scanning without
ECG-based tube current modulation. The mean effective doses were reduced to
less than 10 mSv for 64-slice CT coronary angiography performed with ECG-based
tube current modulation [38, 39], although it is still much higher than those
from prospective gating protocols.
Studies comparing prospective and retrospective gating
further confirmed the significant reduction of radiation dose resulting from
the former imaging protocol. Shuman et al. in their prospective study
compared a group of patients who underwent prospectively gated cardiac CT with
another matched group of patients who underwent retrospectively gated cardiac
CT. Similar image quality of coronary segments was scored for both groups, but
77% radiation dose reduction was achieved in the prospectively gated group
. This was also confirmed by another two comparative studies performed by
Hirai et al. and Earls et al. who both showed the similar image
quality between prospective and retrospective gated imaging, but with dose
reduction of 79% and 83% achieved in the prospective groups [31, 32]. Most
recently, Earls et al. reported their experience of using prospective
gating in the largest clinical group including more than 2000 cases . With
adequate preparation and patient selection, they concluded that most patients
would benefit from prospective gating with acceptable diagnostic images and
significant reduction of effective radiation dose, subsequently reducing the
risk of developing radiation-induced malignancies.
Radiation dose can be further reduced with reduction of
the tube voltage (kVp), in addition to the tube current modulation which is
available in most of the 64-slice scanners. Researchers investigated the
prospective gating with different kVp, and its effect on radiation dose, and
results are promising. Stolamann et al. studied the image quality and
radiation dose with dual source CT prospective gating by using different
protocols . Their results showed no significant differences in image
quality between 100 kV and 120 kV protocols, but with significant reduction of
radiation dose achieved in 100 kV protocols (1.2 mSv � 0.2) compared with 120
kV protocols (2.6 mSv � 0.5). Gopal et al. in their recent study
consisting of 149 patients compared prospective gating and retrospective gating
protocols with different kV groups . Their results showed that a reduction
of radiation exposure up to 90% was achieved with use of 100 kVp and when
compared to the conventional prospective gating at 120 kVp. Therefore, there is
still room for radiation dose reduction when using the prospective gating
technique, although more data from multicentres are needed to corroborate these
It is important to note that while prospective gating
leads to a significant reduction in effective radiation dose and provides
equivalent or improved image quality relative to retrospective gated images,
studies reported in the literature highlight some important limitations to the
current 64-slice CT (including dual source). The main limitation lies in the
fact that image quality is dependent on the heart rate, heart rate variation
and body mass index (BMI). Maximum heart rate threshold is between 63-75 bmp
for prospective gated imaging. When heart rate is greater than 70 bmp, heart
rate variation greater than 10 bmp, or BMI greater than 30 kg/m2,
lower image quality occurs as reported by recent studies [35, 36]. All of these
limitations indicate that prospective gating is limited to patient cohorts
strictly defined by the above three factors, thus the prospective gating
protocol applies only to appropriately selected patients.
Further technical developments in MSCT technique overcome
the abovementioned limitations with the emergence of new generation of MSCT
techniques such as 256- and 320-slice CT scanners. Longer z-axis coverage
available with 256 and 320-slice scanners ranging from 12.8 cm to 16 cm in one
gantry rotation permits full cardiac coverage in one gantry rotation with
prospective gating, thus, eliminating the restrictions and limitations
associated with 64-slice scanners [9, 39-41]. Weigold et al. reported
the superiority of 256 prospective gating CT in their initial experience with
high image quality, low dose, independent of higher heart rates and higher BMI
. Studies by others using 320-slice CT further demonstrated the improvement
of prospective gating with the new generation of CT scanners [23, 24]. The
majority of patients could be imaged in a single heartbeat with excellent image
quality, according to the study performed by Rybicki et al. . Also,
patients with cardiac arrhythmias are no longer excluded from the cardiac CT
Diagnostic accuracy of prospective ECG-gated CT angiography in CAD
Despite the promising aspect of significant reduction of
radiation dose with prospective gating, there is lack of sufficient evidence to
show the diagnostic value or performance of prospective gating in the detection
of coronary artery disease. Most of the studies currently available in the
literature addressed the image quality and reduction of radiation dose when
comparing prospective with retrospective gated protocols. A direct comparison
between prospective gating and conventional coronary angiography is scarce and
data is limited for the diagnosis of coronary artery stenosis. Scheffel et
al. presented the first report demonstrating the diagnostic performance of
low-dose prospective gating CT for the diagnosis of CAD . Diagnostic
accuracy was obtained in patients with heart rate less than 70 bmp with
prospective gated coronary MSCT with more than 96% sensitivity and specificity,
whether the analysis was segment-based, vessel-based or patient-based.
Stolzmann et al. also reported the high diagnostic accuracy of
prospective gating for diagnosis of CAD with low radiation dose, even in the
presence of heavy calcification, despite the fact that increased rate of
non-diagnostic segments was observed due to heavy calcification . Further
studies comparing prospective gating with gold standard coronary angiography
are required to verify the diagnostic value of this rapidly growing CT imaging
Apparently, there are two important limitations of
prospective gating performed with 64-slice CT: prospective gating is limited to
heart rates lower than 75 bpm due to short z-axis coverage. The z-axis coverage
during image acquisition with 64-slice CT is only 4 cm, thus three to five dataset
are required subsequently to image the entire heart. Stair-step artefacts due
to misalignment of two adjacent datasets may happen if the position of the
patient on the CT table changes during table travel, or heart rate is irregular
or heart rate variation is great during the scan. Husmann et al. noticed
that 62% of patients have stair-step artefacts in prospective gated coronary CT
angiography of coronary arteries . The stair-step artefacts are mainly
determined by the motion of the patient during the CT scan and by motion of the
heart, especially since heart rates are apparently variable. Second, cardiac
images are acquired during only a small portion of the R-R interval; thus,
functional information about cardiac valve motion or wall motion is not
The first limitation has been addressed with the use of
256 or 320 slice CT as shown by some studies mentioned above [8, 9, 23, 24].
With extended z-axis coverage, images can be acquired within a single gantry
rotation, thus eliminating the table movement during data acquisition,
consequently eliminating the stair-step artefacts. The limitation of no
functional information has also been overcome with the use of the new
generation of CT technique since myocardial perfusion imaging can be obtained
with 256 or 320-slice prospective gating. Kitagawa et al. in their
initial experience demonstrated that 320-slice CT allows for simultaneous
perfusion imaging for the entire myocardium . Early studies showed the
accuracy of 256- and 320-slice CT perfusion imaging for the simultaneous
evaluation of coronary atherosclerosis and its physiological significance with
a mean dose of 13.5 � 3.5 mSv [44, 45]. Apparently the radiation dose is higher
than that acquired with 64-slice prospective gating technique, thus, further
technical improvement to reduce radiation dose is necessary.
Retrospective or prospective gated imaging for MSCT in CAD?
It seems that the current direction of using MSCT in
cardiac imaging is moving from previous retrospective gating to prospective
gating, and this is demonstrated by the increasing reports available in the
literature over the last few years. The main driving force for this trend is
the reduction of radiation dose, which is the most attractive aspect of
prospective gating technique. Certainly this is only made available due to the
technical developments of multislice CT technique, especially with increased
temporal resolution. In order to acquire diagnostic quality images, prospective
gating CT scans must be performed with use of 64- or more slice CT scanners.
While radiation dose is significantly lower than that acquired with
retrospective gating technique, the evidence of prospective gating for
diagnosis of coronary artery disease is scarce at this stage. Thus, it is too early
to draw conclusions that prospective gating can be used as a reliable
alternative to conventional coronary angiography for the diagnosis of coronary
artery disease before adequate research evidence is available.
With more research findings available in the literature in
the near future, it is expected that multislice CT will be used as a first line
technique in cardiac imaging, possibly with prospective gating replacing the
traditional retrospective gating technique. There is no doubt that multislice CT
has entered a new era in cardiac imaging with the advent of 64-, 256- and
320-slice scanners, and its applications in clinical practice will benefit more
patients suspected of coronary artery disease. While reduction of radiation
dose is important, the most important aspect of cardiac CT is the image quality
required for diagnostic purposes. Thus, both of these two factors need to be
taken into account when choosing prospective gating CT coronary angiography in
the diagnosis of coronary artery disease (Table 1). The following
recommendations aim to provide some kind of guidance for readers using
multislice CT angiography in cardiac imaging:
With use of 64-slice or dual source CT, in patients suspected of CAD for
whom only the cardiac anatomy or presence or absence of CAD is the main
concern, prospective gating is suggested;
�With use of 64-slice or dual source CT in patients suspected of CAD, if
cardiac functional information will make a meaningful or significant
contribution to the CT assessment or clinical treatment, use of retrospective
gating is suggested with additional dose being justified;
With use of 256-or 320-slice CT in cardiac imaging, prospective gating
is recommended since it allows acquisition of dataset in one gantry rotation,
thus providing both anatomical assessment and physiological evaluation;
With use of prospective gated protocol, 100 kVp is recommended in
patients with BMI less than 30 for further reduction of the effective radiation
Narrowing the phase window width in prospective gated protocol is
recommended to reduce patient radiation dose in a single heartbeat CT
angiography (256- or 320-slice CT).
Table 1 Comparison of prospective ECG-gating and retrospective ECG-gating for diagnosis of coronary artery disease (with 64- or more detector row scanners).
Nieman K, Oudkerk M, Rensing BJ et al. Coronary angiography with multi-slice computed tomography. Lancet 2001; 357(9256):599-603.
O�Malley P, Taylor A, Jackson J et al. Prognostic value of coronary electron-beam computed tomography for coronary artery disease events in asymptomatic populations. Am J Cardiol 2001; 87:1335-9.
Danias PG, Roussakis A, Ioannidis JP. Diagnostic performance of coronary magnetic resonance angiography as compared against conventional X-ray angiography: a meta-analysis. J Am Coll Cardiol 2004; 44(9):1867-76.
Finn JP, Nael K, Deshpande V et al. Cardiac MR imaging: state of the technology. Radiology 2006; 241(2):338-54.
Kalendar WA. Computed tomography: fundamentals, system technology, image quality, applications. Munich, Germany: MCD Verlag, 2000: 35-81.
Hoffmann U, Moselewski F, Cury RC et al. Predictive value of 16-slice multidetector spiral computed tomography to detect significant obstructive coronary artery disease in patients at high risk for coronary artery disease: patient-versus segment-based analysis. Circulation 2004; 110(17):2638-43.
Raff GL, Gallagher MJ, O'Neill WW et al. Diagnostic accuracy of noninvasive coronary angiography using 64-slice spiral computed tomography. J Am Coll Cardiol 2005; 46(3):552-7.
Kido T, Kurata A, Higashino H et al. Cardiac imaging using 256-detector row four-dimensional CT: preliminary clinical report. Radiat Med 2007; 25(1):38-44.
Rybicki FJ, Otero HJ, Steigner ML et al. Initial evaluation of coronary images from 320-detector row computed tomography. Int J Cardiovasc Imaging 2008; 24(5):535-46.
Sun Z, Jiang W. Diagnostic value of multislice computed tomography angiography in coronary artery disease: a meta-analysis. Eur J Radiol 2006; 60(2):279-86.
Nieman K, Cademartiri F, Lemos PA et al. Reliable noninvasive coronary angiography with fast submillimeter multislice spiral computed tomography. Circulation 2002; 106(16):2051-4.
Ropers D, Baum U, Pohle K et al. Detection of coronary artery stenoses with thin-slice multi-detector row spiral computed tomography and multiplanar reconstruction. Circulation 2003; 107(5):664-6.
Kuettner A, Trabold T, Schroeder S et al. Noninvasive detection of coronary lesions using 16-detector multislice spiral computed tomography technology: initial clinical results. J Am Coll Cardiol 2004; 44(6):1230-7.
Achenbach S, Ropers D, Pohle FK et al. Detection of coronary artery stenoses using multi-detector CT with 16 x 0.75 collimation and 375 ms rotation. Eur Heart J 2005; 26(19):1978-86.
Vanhoenacker PK, Heijenbrok-Kal MH, Van Heste R et al. Diagnostic performance of multidetector CT angiography for assessment of coronary artery disease: meta-analysis. Radiology 2007; 244(2):419-28.
Sun Z, Lin C, Davidson R et al. Diagnostic value of 64-slice CT angiography in coronary artery disease: a systematic review. Eur J Radiol 2008; 67(1):78-84.
Abdulla J, Abildstrom SZ, Gotzsche O et al. 64-multislice detector computed tomography coronary angiography as potential alternative to conventional coronary angiography: a systematic review and meta-analysis. Eur Heart J 2007; 28(24):3042-50.
Flohr TG, McCollough CH, Bruder H et al. First performance evaluation of a dual-source CT (DSCT) system. Eur Radiol 2006; 16(2):256-68.
Leber AW, Johnson T, Becker A et al. Diagnostic accuracy of dual-source multi-slice CT-coronary angiography in patients with an intermediate pretest likelihood for coronary artery disease. Eur Heart J 2007; 28(19):2354-60.
Brodoefel H, Burgstahler C, Tsiflikas I et al. Dual-source CT: effect of heart rate, heart rate variability, and calcification on image quality and diagnostic accuracy. Radiology 2008; 247(2):346-55.
Johnson TR, Nikolaou K, Busch S et al. Diagnostic accuracy of dual-source computed tomography in the diagnosis of coronary artery disease. Invest Radiol 2007; 42(10):684-91.
Rixe J, Rolf A, Conradi G et al. Detection of relevant coronary artery disease using dual-source computed tomography in a high probability patient series: comparison with invasive angiography. Circ J 2009; 73(2):316-22.
Steigner ML, Otero HJ, Cai T et al. Narrowing the phase window width in prospectively ECG-gated single heart beat 320-detector row coronary CT angiography. Int J Cardiovasc Imaging 2009; 25(1):85-90.
Kitagawa K, Lardo AC, Lima JAC et al. Prospective ECG-gated 320 row detector computed tomography: implications for CT angiography and perfusion imaging. Int J Cardiovasc Imaging 2009; (in press).
Hsieh J, Londt J, Vass M et al. Step-and-shoot data acquisition and reconstruction for cardiac x-ray computed tomography. Med Phys 2006; 33(11):4236-48.
Husmann L, Valenta I, Gaemperli O et al. Feasibility of low-dose coronary CT angiography: first experience with prospective ECG-gating. Eur Heart J 2008; 29(2):191-7.
Ropers D, Rixe J, Anders K et al. Usefulness of multidetector row spiral computed tomography with 64- x 0.6-mm collimation and 330-ms rotation for the noninvasive detection of significant coronary artery stenoses. Am J Cardiol 2006; 97(3):343-8.
Mollet NR, Cademartiri F, van Mieghem CA et al. High-resolution spiral computed tomography coronary angiography in patients referred for diagnostic conventional coronary angiography. Circulation 2005; 112(15):2318-23.
Shuman WP, Branch KR, May JM et al. Prospective versus retrospective ECG gating for 64-detector CT of the coronary arteries: comparison of image quality and patient radiation dose. Radiology 2008; 248(2):431-7.
Hirai N, Horiguchi J, Fujioka C et al. Prospective versus retrospective ECG-gated 64-detector coronary CT angiography: assessment of image quality, stenosis, and radiation dose. Radiology 2008; 248(2):424-30.
Earls JP, Berman EL, Urban BA et al. Prospectively gated transverse coronary CT angiography versus retrospectively gated helical technique: improved image quality and reduced radiation dose. Radiology 2008; 246(3):742-53.
Earls JP, Schrack EC. Prospectively gated low-dose CCTA: 24 months experience in more than 2000 clinical cases. Int J Cardiovasc Imaging 2008; (in press).
Leschka S, Stolzmann P, Schmid FT et al. Low kilovoltage cardiac dual-source CT: attenuation, noise, and radiation dose. Eur Radiol 2008; 18(9):1809-17.
Gopal A, Mao SS, Karlsberg D et al. Radiation reduction with prospective ECG-triggering acquisition using 64-multidetector Computed Tomographic angiography. Int J Cardiovasc Imaging 2009; 25(4):405-16.
Gutstein A, Wolak A, Lee C et al. Predicting success of prospective and retrospective gating with dual-source coronary computed tomography angiography: development of selection criteria and initial experience. J Cardiovasc Comput Tomogr 2008; 2(2):81-90.
Stolzmann P, Leschka S, Scheffel H et al. Dual-source CT in step-and-shoot mode: noninvasive coronary angiography with low radiation dose. Radiology 2008; 249(1):71-80.
Scheffel H, Alkadhi H, Leschka S et al. Low-dose CT coronary angiography in the step-and-shoot mode: diagnostic performance. Heart 2008; 94(9):1132-7.
Klass O, Jeltsch M, Feuerlein S et al. Prospectively gated axial CT coronary angiography: preliminary experiences with a novel low-dose technique. Eur Radiol 2009; 19(4):829-36.
Hausleiter J, Meyer T, Hadamitzky M et al. Radiation dose estimates from cardiac multislice computed tomography in daily practice: impact of different scanning protocols on effective dose estimates. Circulation 2006; 113(10):1305-10.
Stolzmann P, Scheffel H, Schertler T et al. Radiation dose estimates in dual-source computed tomography coronary angiography. Eur Radiol 2008; 18(3):592-9.
Weigold WG, Olszewski ME, Walker MJ. Low-dose prospectively gated 256-slice coronary computed tomographic angiography. Int J Cardiovasc Imaging 2009; (in press).
Stolzmann P, Scheffel H, Leschka S et al. Influence of calcifications on diagnostic accuracy of coronary CT angiography using prospective ECG triggering. AJR Am J Roentgenol 2008; 191(6):1684-9.
Husmann L, Herzog BA, Burkhard N et al. Body physique and heart rate variability determine the occurrence of stair-step artefacts in 64-slice CT coronary angiography with prospective ECG-triggering. Eur Radiol 2009; 19(7):1698-703.
George RT, Yousef O, Kitagawa K et al. Quantification of myocardial perfusion in patients using 256-row multidetector computed tomography: evaluation of endocardial vs epicardial blood flow. Circulation 2007; 116:II-563.
George RT, Kitagawa K, Laws K et al. Combined adenosine stress perfusion and coronary angiography using 320-row detector dynamic volume computed tomography in patients with suspected coronary artery disease. Circulation 2008; 118:S_936.
Received 26 May 2009; received in revised form 28 September
2009, accepted 30 September 2009
Correspondence: Discipline of Medical Imaging, Department of Imaging and Applied Physics, Curtin University of Technology, GPO Box, U1987, Perth, Western Australia 6845, Australia. Tel.: +61-8-92667509; Fax: +61-8-92662377; E-mail: email@example.com (Zhonghua Sun).
Please cite as: Sun Z,
Multislice CT angiography in cardiac imaging: prospective ECG-gating or retrospective ECG-gating?, Biomed Imaging Interv J 2010; 6(1):e4
Except where otherwise noted,
articles published in the Biomedical Imaging and Intervention Journal
are distributed under the terms of the Creative
Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the
original work is properly
including full bibliographic details and the URL, and this statement is included.