ReviewProspective versus retrospective ECG-gated multislice CT coronary angiography: A systematic review of radiation dose and diagnostic accuracy
Introduction
Since the introduction of 64- or more-slice CT technology, multislice CT (MSCT) angiography has been increasingly used in the diagnosis of coronary artery disease (CAD) due to its improved spatial and temporal resolution [1], [2], [3], [4]. Studies have shown that MSCT angiography is a highly accurate method compared to invasive coronary angiography as it provides high sensitivity and specificity [1], [2], [3], [4], [5], [6]. In particular, MSCT angiography has been reported to demonstrate a very high negative predictive value (more than 95%), indicating that it can be used as a reliable screening technique for patients suspected of CAD, thereby reducing the need for invasive coronary angiography [5]. The non-invasive nature of MSCT angiography and increased availability of MSCT scanners have led to rapidly increasing numbers of CT examinations performed worldwide. However, high radiation dose of MSCT angiography and its associated risk of radiation-induced malignancy have raised serious concerns in the medical field [7], [8], [9], [10].
In response to these concerns, tremendous progress has been made to lower radiation dose for cardiac MSCT angiography, and various strategies have been proposed to address this issue. These include automatic tube current modulation, reduced X-ray tube voltage and tube current, scan range, and prospective ECG-gating [11]. Of these dose-saving strategies, prospective ECG-gated scanning represents the most recently developed approach with significant reduction of radiation dose when compared to conventional retrospective ECG-gating [12].
Radiation exposure with prospective ECG-gating has been increasingly studied and evaluated with retrospective-gating in the literature [11], [12], [13], [14]. Despite promising results having been achieved in dose reduction, there are concerns about the image quality and diagnostic value of prospective ECG-gating, since only a portion of data is acquired when compared to the volumetric data that is available with retrospective-gating protocol. Thus, the purpose of this study was to perform a systematic review of radiation dose and diagnostic accuracy of prospective versus retrospective ECG-gated MSCT angiography in the diagnosis of CAD, based on the currently available literature.
Section snippets
Criteria for data selection and literature searching
A search of Pubmed/Medline and Sciencedirect databases of English literature was performed for articles comparing prospective ECG-gated MSCT angiography with retrospective ECG-gated scans in patients with suspected or confirmed CAD. Inclusion criteria required that articles must be peer-reviewed and published in the English language. The keywords used in searching the references included: MSCT angiography with prospective ECG-gating/ECG-triggering, radiation dose of MSCT angiography, diagnostic
General information
25 studies met the selection criteria and 22 were eligible for analysis [16], [17], [18], [19], [20], [21], [22], [23], [24], [25], [26], [27], [28], [29], [30], [31], [32], [33], [34], [35], [36], [37], [38], [39], [40]. Three studies were excluded from the analysis as they either focused on the assessment of coronary stenting or coronary bypass instead of coronary artery disease [38], [39], [40]. There are altogether 37 comparisons from these 22 studies as seven studies involved different
Discussion
Our analysis presents three findings which we consider important for clinical application of MSCT angiography in CAD: first, prospective ECG-gating leads to a significant reduction of DLP and effective dose by more than 60% (up to 90% in some studies) when compared to retrospective ECG-gating. Second, diagnostic image quality of prospective ECG-gating is comparable to that of retrospective ECG-gating, in terms of both subjective and objective assessment of coronary segments. This indicates that
Conflict of interest
None.
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2018, Radiotherapy and OncologyCitation Excerpt :Our Hospital authorized the retrospective use of the anonymized image set for the study purposes. All ECG-gated CT scans were performed on the same 64 slices CT scanner (Lightspeed VCT Scanner, General Electric Healthcare, Waukesha, WI, USA), with intravenous contrast (Ultravist 370 mg/ml), adopting a dedicated retrospective ECG-gated spiral algorithm [10ā12]. A spiral CT scan with continuous table movement and data acquisition was performed; simultaneously, the patientās ECG was recorded and images acquired across different heartbeats, creating a heart phase-consistent sequence.