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DOI: 10.1055/s-0043-120528
Multidetector Computed Tomography Angiography (MD-CTA) of Coronary Artery Bypass Grafts – Update 2017
Multidetektor-Computertomografie-Angiografie (MD-CTA) aortokoronarer Bypässe – Update 2017Correspondence
Publication History
05 May 2017
19 September 2017
Publication Date:
03 November 2017 (online)
- Introduction
- Search strategy and selection criteria
- Diagnostic accuracy of MD-CTA
- Current advances in examination technique
- Recommendations
- Future perspectives
- Limitations
- Summary
- References
Abstract
Background Coronary artery bypass grafting (CABG) is still an important therapeutic approach in the treatment especially of advanced coronary artery disease. In this study, we elucidate the current role of multidetector computed tomography angiography (MD-CTA) in imaging patients after CABG surgery.
Method This study is based on recent reports in the literature (2007 – 2016) on imaging of CABG using 64-slice MD-CT scanners and beyond. We included 13 reports that compared ECG-gated MD-CTA with conventional invasive coronary angiography (ICA) as the reference standard for the assessment of graft patency and for the detection of > 50 % stenoses. These studies had to provide absolute values for true-positive, true-negative, false-positive and false-negative results or at least allow calculation of these numbers. In total, 1002 patients with 2521 bypass grafts were the basis for this review.
Results and Conclusion The sensitivity and specificity for the assessment of graft patency or the detection of > 50 % graft stenosis were 97.2 % and 97.5 %, respectively. The negative and positive predictive values were 93.6 % and 99 %, respectively. By using prospective ECG-gating and an increasing pitch factor, the radiation dose exposure declined to 2.4 mSv in the latest reports. ECG-gated MD-CTA provides a fast and reliable, noninvasive method for assessing patients after CABG. The most substantial benefit of the newest CT scanner generations is a remarkable reduction of radiation dose exposure while maintaining a still excellent diagnostic accuracy during recent years.
Key Points
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MD-CTA using 64-slice MDCT scanners and beyond is a reliable, noninvasive method for evaluating CABGs.
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Technical advances such as prospective ECG-gating, iterative reconstruction algorithms and high-pitch scanning lead to a remarkable drop-down in radiation dose exposures as low as 2.4 mSv.
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Despite significant dose reductions, MD-CTA could maintain a high diagnostic accuracy in evaluating CABGs in recent years.
Citation Format
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Jungmann F, Emrich T, Mildenberger P et al. Multidetector Computed Tomography Angiography (MD-CTA) of Coronary Artery Bypass Grafts – Update 2017. Fortschr Röntgenstr 2018; 190: 237 – 249
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Zusammenfassung
Hintergrund Die aortokoronare Bypassoperation stellt unverändert einen wichtigen Bestandteil in der Behandlung der koronaren Herzerkrankung insbesondere in fortgeschrittenen Krankheitsstadien dar. In der vorliegenden Arbeit soll der aktuelle Stellenwert der Multidetektor-CT-Angiografie (MD-CTA) bei Patienten nach stattgehabter aortokoronarer Bypassoperation (ACVB) dargelegt werden.
Methode Die vorliegende Übersichtsarbeit basiert auf Publikationen aus den Jahren 2007 – 2016 zur nicht-invasiven Bildgebung von Patienten nach ACVB-Operation, die an MD-CT-Geräten mit mindestens 64 Zeilen untersucht wurden. Voraussetzung für eine Berücksichtigung in der Analyse waren Angaben zu den absoluten Vorhersagewerten (richtig-positiv, richtig-negativ, falsch-positiv und falsch-negativ) bzw. ihre Berechnung musste möglich sein. Insgesamt konnten 13 Publikationen berücksichtigt werden, bei denen die EKG-getriggerte CT-Angiografie mit der konventionellen Koronarangiografie als Referenzstandard hinsichtlich Bypassoffenheit bzw. der Detektion von > 50 % Bypassstenosen verglichen wurde. Insgesamt wurden 1002 Patienten mit 2521 Bypässen in die Arbeit eingeschlossen.
Ergebnisse und Schlussfolgerung Die gepoolte Sensitivität und Spezifität in der Evaluation der Bypassoffenheit bzw. der Detektion von > 50 % Bypassstenosen betrugen 97,2 % und 97,5 %. Der gemittelte positiv prädiktive Wert und der gemittelte negativ prädiktive Wert erreichte 93,6 % bzw. 99 %. Durch prospektive EKG-Triggerung und einer Erhöhung des Pitch-Faktors konnte die Strahlenexposition in den neuesten Publikationen auf bis zu 2,4 mSv gesenkt werden. Die EKG-getriggerte MD-CTA ist eine schnelle und zuverlässige Methode zur Untersuchung von Patienten nach ACVB-Operation. Der größte Fortschritt der neueren CT-Scanner-Generationen ist eine signifikante Reduktion der Strahlenexposition bei einer unverändert hohen diagnostischen Genauigkeit in der Bypassbeurteilung in den vergangenen Jahren.
Kernaussagen
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Die MD-CTA ist eine zuverlässige, nicht-invasive Methode zur Beurteilung aortokoronarer Bypässe.
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Technische Weiterentwicklungen wie prospektive EKG-Triggerung, iterative Rekonstruktionsalgorithmen und high-pitch Technik führen zu einer deutlichen Reduktion der Strahlenexposition auf bis zu 2,4 mSv.
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In den vergangenen Jahren konnte die diagnostische Genauigkeit der MD-CTA auf konstant hohem Niveau gehalten werden, mit weiterhin ausgezeichneten Sensitivitäten und negativ prädiktiven Werten in Bezug auf Bypassoffenheit bzw. der Detektion relevanter Bypassstenosen.
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Key words
coronary artery bypass grafting - multidetector computed tomography - cardiac-gated imaging techniques - vascular patency - radiation monitoringIntroduction
Ischemic heart disease is still the most common cause of death in Europe [1]. Acute myocardial infarction, chronic ischemic heart disease and congestive heart failure caused about 19 % of all deaths in 2013 in Germany. In 2012, about 665 000 patients suffered from ischemic heart disease, 128 000 of whom died [2]. In the United States, coronary heart disease (CHD) caused approximately 788 000 deaths in 2009 [3]. Despite improving drug therapy, percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG) are essential parts of therapy of coronary artery disease (CAD). In 2013, about 54 000 patients underwent CABG surgery, whereas 342 749 patients were treated with PCI in Germany [2]. Decreasing mortality rates of acute myocardial infarction (between 2000 and 2010: reduction of about 17 %) reveal the efficiency of the on-going medical progress.
The main indications for bypass grafting are three-vessel disease (3VD) and left main disease (LM) [4]. The SYNTAX trial was a multicenter long-term randomized study that compared the outcomes of PCI with those of CABG in LM disease and 3VD [5]. After 5 years, there were significantly higher rates of MACCE (major adverse cardiac and cerebrovascular events) in the PCI-treated patients (37.3 % vs. 26.9 % in the CABG group) and significantly higher rates of estimated myocardial infarction (9.7 % vs. 3.8 % in the CABG group) than in the CABG group. These results indicate that patients with more complex lesions should undergo bypass grafting.
The need to image coronary artery bypass grafts postoperatively is due to their limited lifetime [6]. Several vessels have been used for coronary bypass grafting, whereas the internal mammary artery (IMA) is considered the vessel of choice [7]. As early as in 1972, George E. Green described the technique and the clinical course of internal mammary-to-coronary artery anastomosis in 165 patients and concluded that their graft patency rate is superior to that of saphenous vein grafts [6]. Tatoulis et al. revealed a ten-year graft patency rate for the right (RIMA) and left internal mammary artery (LIMA) to the left anterior descending artery (LAD) of about 95 % [8]. The ten-year RIMA and LIMA patency rate to the left circumflex artery (LCX) was around 90 % [8]. On the other hand, early graft occlusion within the first year after surgery in IMA grafts occurs in 3.4 % of women and 5.7 % of men [9].
Venous grafts in general show an inferior graft patency rate. Early disease of saphenous vein grafts (SVG) is caused by thrombosis. About 12 % of SVGs occlude early after grafting (up to 6 months after operation) [10]. Intimal hyperplasia results in delayed venous graft disease between 1 to 12 months, and atherosclerosis causes late graft disease starting as early as one year after CABG [11]. Ten years after CABG surgery, the patency rate of SVG drops down to 60 % [10] ([Fig. 1], [2]).
Nowadays, for complete arterial revascularization, radial artery and epigastric artery grafts can be used. A systematic review illustrates that radial artery grafts prepared as free grafts are superior to saphenous veins grafts at 1 – 5 years as well as > 5 years after operation concerning patency rates, but in comparison with IMA grafts, they show higher rates of acute occlusion [12]. In selected cases, epigastric artery grafts may be used for arterial revascularization of distal segments of the RCA ([Fig. 3]).
MD-CTA of CABGs further helps in detecting patients with unprotected coronary territories, myocardial segments that are not adequately supplied due to stenosis or occlusion of coronary artery or bypass graft. In coronary artery bypass patients, MD-CTA appears to have a prognostic value by assessing unprotected coronary territories (UCTs) [13]. Patients without UCTs had the lowest rate for cardiac death and nonfatal myocardial infarction.
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Search strategy and selection criteria
For the present review, we selected publications that compared the accuracy of MD-CTA in evaluating patients after CABG surgery performed on 64-slice and beyond scanners with ICA as the reference standard. Articles were searched in PubMed using combined terms “multidetector computed tomography” or “multidetector computed tomography angiography”, “bypass graft” or “coronary artery bypass graft”. These studies had to evaluate the accuracy of MD-CTA to detect graft occlusion or > 50 % graft stenosis as well as provide absolute numbers of true-positive, true-negative, false-positive and false-negative results or at least allow for calculation of these numbers. We found 13 references that met the inclusion criteria published between 2007 and 2016. Publications that were already evaluated in the review of Hamon et al. were excluded from this study [14]. Thus, a total of 1002 patients and 2521 bypass grafts from 13 publications could be included in the present study.
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Diagnostic accuracy of MD-CTA
Assessment of CABG ([Table 1])
author [year] |
CT scanner-sections |
patients/bypasses |
arterial/venous grafts |
Se [%] total/arterial/venous |
Sp [%] total/arterial/venous |
PPV [%] |
NPV [%] |
radiation dose [mSv] |
Andreini [2010] [17] |
64-slice |
119/277[1] |
||||||
40/96[2] |
44/52 |
100 |
100 |
100 |
100 |
3.5 ± 1.42 |
||
39/86[3] |
43/43 |
100 |
100 |
100 |
100 |
7.4 ± 2.63 |
||
40/95[4] |
45/50 |
100 |
98.4 |
96.7 |
100 |
27.8 ± 9.44 |
||
Feuchtner [2007] [39] |
64-slice |
41/70 |
46/24 |
85 |
95 |
80 |
96 |
N/A4 |
Gorantla [2012] [40] |
64-slice |
36/89 |
34/55 |
95 |
98.5 |
75 |
99.4 |
14.74 |
Lee [2011] [41] |
64-slice |
26/64 |
||||||
12/292 |
13/16 |
92.3 |
93.7 |
92.3 |
93.7 |
6.5 ± 0.62 |
||
14/354 |
18/17 |
93.3 |
90 |
87.5 |
94.7 |
21.2 ± 34 |
||
Nazeri [2009] [42] |
64-slice |
98/287 |
89/198 |
98/100/98 |
97/99/95 |
96/67/97 |
99/100/97 |
N/A4 |
Onuma [2007] [43] |
64-slice |
53/146 |
65/73 |
–/100/100 |
–/91.4/98.1 |
–/73.7/95.5 |
–/100/98.1 |
N/A4 |
Romagnoli [2010] [44] |
64-slice |
77/210 |
115/97 |
–/100/94.4 |
–/97.7/98.4 |
N/A |
N/A |
N/A4 |
Sahiner [2012] [18] |
64-slice |
284/684 |
264/420 |
98.8/100/98.3 |
99.4/99.5/99.3 |
98.2/98/98.3 |
99.6/100/99.3 |
19.5 ± 7.2 |
Sahiner [2012] [20] |
64-slice |
71/173 |
71/102 |
80/100/60 |
98/97/99 |
73/71/75 |
98/100/98 |
17.2 ± 6.54 |
Tochii [2010] [45] |
64-slice |
19/651 |
30/35 |
100 |
93 |
16.7 |
100 |
N/A4 |
Weustink [2009] [15] |
64-slice |
52/1521 |
50/102 |
100 |
100 |
100 |
100 |
22.1 ± 2.84 |
De Graaf [2011] [19] |
320-slice |
38/89 |
28/61 |
96/100/95 |
92/91/93 |
83/71/87 |
98/100/97 |
7.8 ± 3.34 11.2 ± 4.14 |
Yuceler [2014] [16] |
256-slice |
88/215 |
93/122 |
97.1 |
99.6 |
94.4 |
99.8 |
2.4 ± 0.92 2.75 ± 0.52 |
Se = sensitivity; Sp = specificity; PPV = positive predictive value; NPV = negative predictive value.
Se = Sensitivität; Sp = Spezifizität; PPV = positiver prädiktiver Wert; NPV = negativer prädiktiver Wert.
1 segment-based analysis; non-evaluable bypass grafts were considered positive for occlusion and > 50 % stenosis.
Analyse auf Segmentebene; nicht evaluierbare Bypassgefäße wurden als positiv für Verschluss und > 50 % Stenose gewertet.
2 prospective ECG-gated (BMI-adapted).
prospektive EKG-Triggerung (Dosis an BMI adaptiert).
3 prospective ECG-gated (120 kV).
prospektive EKG-Triggerung (120 kV).
4 retrospective ECG-gated; > 50 % diameter stenosis.
retrospektive EKG-Triggerung; > 50 % Stenose.
Many studies listed in [Table 1] achieved a negative predictive value and sensitivity of 100 % or nearly 100 % in 64-slice MDCT and beyond [15] [16]. The sensitivity and specificity ranged between 80 – 100 % and 93 – 100 % in the detection of graft stenosis > 50 % and graft occlusion. Sahiner et al. investigated 284 patients with a total of 684 bypass grafts, whereas Andreini et al. examined 119 patients with 277 bypass grafts [17] [18]. Both studies reported a sensitivity, specificity and negative predictive values of more than 97 %.
To our knowledge, only two studies have used 256-slice CT and 320-slice CT to assess bypass grafts compared with ICA [16] [19]. The diagnostic accuracy on 256- and 320-MDCT was similar to studies using 64-slice MDCT scanners.
Yuceler et al. described a trend towards lower image quality in patients with higher heart rates [16]. In the lower heart rate group, arterial grafts could be assessed more easily compared with arterial grafts in the higher heart rate group. Mean heart rates in most studies ranged between 58 – 70 beats/min. Only one study listed in [Table 1] investigated the accuracy of 64-slice CT in patients with a mean heart rate of 80 beats/min with a sensitivity and negative predictive value of 90 % and 98 %, respectively [20].
To calculate the sensitivity, specificity, positive as well as negative predictive value, we worked out exact values of true-positive, true-negative, false-positive and false-negative results in evaluating occlusion or substantial stenosis. After that, we calculated the pooled sensitivity, specificity, positive predictive value and negative predictive value ([Table 2]). Compared with the reviews of Hamon et al. in 2008 (723 patients with 2023 bypass grafts) and Chan et al. in 2016 (1975 bypass grafts and 5364 patients), there were no significant differences with regard to sensitivity, specificity, positive predictive value and negative predictive value for detecting occlusion or substantial stenosis of bypass grafts [14] [21].
author [year] |
reports analyzed |
patients/bypasses |
Se [%] |
Sp [%] |
PPV [%] |
NPV [%] |
all studies listed in [Table 1] |
13 |
1002/2521 |
97.2 |
97.5 |
93.6 |
99.0 |
64-slice CT listed in [Table 1] |
11 |
876/2217 |
97.3 |
97.6 |
94.0 |
98.9 |
> 64-slice CT listed in [Table 1] |
2 |
126/304 |
96.7 |
97.1 |
89.4 |
99.2 |
Hamon [2010] [14] |
15 |
723/2023 |
97.6 |
96.7 |
92.7 |
98.9 |
Chan [2016] [21] |
31 |
1975/5364 |
96.1 |
96.3 |
94.3 |
99.0 |
Se = sensitivity; Sp = specificity; PPV = positive predictive value; NPV = negative predictive value.
Se = Sensitivität; Sp = Spezifizität; PPV = positiver prädiktiver Wert; NPV = negativer prädiktiver Wert.
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Assessment of native coronary arteries ([Table 3])
author [year] |
CT scanner sections |
patients/native coronary arteries |
Se [%] distal runoffs/non-grafted |
Sp [%] distal runoffs/non-grafted |
PPV [%] distal runoffs/non-grafted |
NPV [%] distal runoffs/non-grafted |
Andreini [2010] [17] |
64-slice |
119/277[1] |
||||
40/194[2] |
91 |
99 |
91 |
99 |
||
39/232[3] |
100 |
99 |
96 |
100 |
||
40/202[4] |
100 |
98 |
94 |
100 |
||
Nazeri [2009] [42] |
64-slice |
98/356 |
97 |
90 |
96 |
93 |
Onuma [2007] [43] |
64-slice |
53/144 |
83.3/100 |
80.2/87.5 |
37.5/96.8 |
97.1/100 |
Romagnoli [2010] [44] |
64-slice |
77/2261 |
95/NA |
97/NA |
N/A |
N/A |
Sahiner [2012] [18] |
64-slice |
284/10201 |
NA/97.8 |
NA/99 |
NA/96 |
NA/99.5 |
Weustink [2009] [15] |
64-slice |
52/2081 |
95/97 |
100/92 |
100/83 |
99/99 |
De Graaf [2011] [19] |
320-slice |
38/152 |
88/83 |
89/77 |
67/77 |
97/83 |
Se = sensitivity; Sp = specificity; PPV = positive predictive value; NPV = negative predictive value; Non-evaluable native coronary arteries were considered positive for occlusion and > 50 % stenosis.
Se = Sensitivität; Sp = Spezifizität; PPV = positiver prädiktiver Wert; NPV = negativer prädiktiver Wert; nicht evaluierbare native Koronararterien wurden als positiv für Verschluss und > 50 % Stenose gewertet.
1 segment-based analysis.
Analyse auf Segmentebene.
2 prospective ECG-gated (BMI-adapted).
prospektive EKG-Triggerung (Dosis an BMI adaptiert).
3 prospective ECG-gated (120 kV).
prospektive EKG-Triggerung (120kV).
4 retrospective ECG-gated; > 50 % diameter stenosis.
retrospektive EKG-Triggerung; > 50 % Stenose.
When imaging patients after coronary artery bypass grafting, one should try to assess the progress of CHD in the non-grafted vessels, too. [Table 3] lists all studies that additionally analyzed native coronary arteries. 7 out of 13 studies evaluated native coronary arteries, whereas 3 of these publications differentiate between distal runoffs (segment of the coronary artery at which the bypass graft was inserted and all segments distally to the inserted segment) and non-grafted coronary arteries [15].
The sensitivity and specificity in the detection of relevant stenosis in native coronary arteries ranged between 83 – 100 % and 77 – 100 %, respectively, whereas the negative predictive value ranged between 83 – 100 %. Most of the studies used a segment-based analysis and analyzed vessels with a diameter of more than 1.5 mm. Andreini et al. presented the largest number of patients (n = 119) with assessment of native coronary arteries after bypass grafting without distinguishing between distal runoffs and non-grafted coronary arteries. This publication achieved sensitivities and specificities ranging between 91 – 100 % and 98 – 99 %, respectively, with an excellent negative predictive value of 99 – 100 % [17].
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Current advances in examination technique
In recent years, there have been tremendous improvements regarding the technique of CT coronary angiography (CTCA), such as the introduction of prospective ECG triggering, the implementation of 64-slice and beyond CT scanners and – last but not least – the introduction of iterative reconstruction algorithms. These improvements have led to a significant drop in radiation dose exposure from about 15 mSv and more to less than 1 mSv going along with significant improvements in temporal resolution in CTCA [22] [23].
Imaging of coronary artery bypass grafts using MD-CTA results in higher radiation exposure basically due to the larger scan range. However, Yuceler et al. implemented a high-pitch spiral acquisition protocol with a second-generation 256-slice CT system for the evaluation of CABG, which resulted in a mean radiation dose of about 2.4 mSv [16]. The image quality of the graft segments was excellent in 92 % of the assessed segments [16]. Goetti et al. implemented a similar high-pitch CT protocol with diagnostic image quality in 99 % of cases [24]. However, in approximately 1 % of the evaluated grafts, the distal anastomosis could not be evaluated adequately due to insufficient diagnostic image quality.
Menke et al. compared prospectively triggered versus retrospectively gated MD-CTA of native coronary arteries by analyzing 20 studies with 3330 patients [25]. Diagnostic quality did not differ between prospective and retrospective gating techniques, whereas radiation dose was significantly lower in the prospectively gated patient group (factor 3.5) [25]. However, higher heart rates in the prospectively gated data sets caused a significant increase in step artifacts and lower image quality [24] [26]. The application of an iterative reconstruction technique in ECG-gated CTCA to rule out coronary artery disease enabled a radiation dose reduction of 63 % as shown by use of a 256-slice MD-CT scanner [23].
Although all studies listed in [Table 1] were performed on ≥ 64-row MDCT scanners, we could reveal relevant differences concerning radiation dose. Based on different acquisition techniques (retrospective vs. prospective ECG-gating, different tube voltages, iterative reconstruction algorithm vs. filtered back projection and pitch factor), the radiation dose ranged between 2.4 (256-slice high-pitch MD-CTA) and 27.8 mSv (retrospectively gated MD-CTA). Although conventional catheter angiography is still regarded as the reference standard in evaluating coronary artery bypass grafts, it is an invasive procedure that is associated with complications ranging between 1 % and 5 % [27] [28]. Compared with ICA, MD-CTA offers additional information such as delineation of the anatomical course of bypass grafts and their topographic relationship to the sternum and the right ventricle, the assessment of the remodeling of bypass grafts, aortic diseases, pathologies of heart valves and extracardiac findings such as pulmonary emphysema or suspicious lung nodules ([Fig. 4]). These findings help in the preoperative planning of redo cardiac surgery, and preoperative CT imaging thus reduces the incidence for bypass graft injury [29].
Pesenti-Rossi et al. investigated the potential benefit of prior CTCA before ICA in patients after coronary artery bypass grafting [30]. In a prospective non-randomized trial, 147 patients with a history of CABG surgery were divided into two groups. Group 1 underwent first-line MD-CTA of CABG while group 2 underwent first-line ICA. 33 of 75 patients (44 %) in group 1 needed further investigation with ICA. Compared with group 2, second-line ICA in group 1 was associated with a significantly lower radiation dose and a significantly lower amount of applied iodinated contrast volume. As most patients in group 1 did not need ICA, there were no differences in cumulative effective dose between the two groups (5.0 vs. 5.1 mSv). MD-CTA of CABG without ICA resulted in an average effective dose of 3.9 mSv. The authors concluded that MD-CTA could serve as a kind of a roadmap for ICA.
Furthermore, MD-CTA plays a crucial role in investigating complications of cardiothoracic surgery (CABG surgery, valve surgery), e. g. mediastinitis, pericardial and pleural effusions, hematoma, acute graft thrombosis or aortic dissection ([Fig. 5]).
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Recommendations
Current Appropriate Use Criteria for Cardiac Computed Tomography comprise symptomatic patients after CABG, localization of CABG and assessment of retrosternal anatomy prior to repeat chest or cardiac surgery [31]. For asymptomatic patients more than five years after CABG, the use of MD-CTA is considered to be uncertain and thus needs further investigation. In asymptomatic patients less than five years after bypass grafting, MD-CTA is regarded as inappropriate.
In the consensus recommendations of the German Radiology Society (DRG), the German Cardiac Society (DGK) and the German Society for Pediatric Cardiology (DGPK), computed tomography should only be performed if graft patency has to be assessed in symptomatic patients and in cases in which conventional catheter angiography is not able to display all CABGs [32].
In our clinical routine, MD-CTA of CABGs is also applied in asymptomatic patients with a positive stress test as well as in patients with atypical chest pain and ambiguous stress tests. Furthermore, MD-CTA plays an important role in preoperative planning for redo cardiac surgery or in the documentation of the postoperative outcome, especially after off-pump CABG surgery. Before redo cardiac surgery, the anatomical course of bypass grafts, especially of LIMA-to-LAD grafts in relation to the sternum, as well as anatomical information of the right ventricle in relation to the sternum are very helpful in order to avoid intraoperative complications ([Fig. 6]).
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Future perspectives
Morphologic assessment of native coronary arteries by MD-CTA in patients with CABG surgery did not show relevant improvements in evaluating substantial stenosis over the past decade. Thus, it can be anticipated that future research should focus on the assessment of myocardial perfusion in CABG patients to detect stenosis-related myocardial ischemia.
In recent years, there have been an increasing number of studies concentrating on the assessment of myocardial perfusion with cardiac computed tomography, which allows detection of myocardial perfusion defects under rest and/or stress. In 2010, Bamberg et al. published first experiences with dynamic myocardial stress perfusion imaging in a 69-year-old study participant using a quantitative 3 D imaging technique to calculate regional MBF [33]. Radiation dose exposure for CTA and CT perfusion imaging (CTP) as “one-stop-shop” cardiac procedure was about 12 mSv.
Okada et al. compared rest and stress (with use of a pharmacological vasodilator such as dipyridamole or adenosine) myocardial CT perfusion with rest and stress single photon emission CT (SPECT) perfusion [34]. In their study, they reported a good correlation between CT and SPECT in the detection of myocardial perfusion defects. Even under resting conditions they revealed most of the reversible SPECT defects by CT perfusion imaging. Tashakkor et al. analyzed CT perfusion studies and achieved a sensitivity, specificity, PPV and NPV of 81 %, 93 %, 87 % and 88 %, respectively, for the combination of CTCA and CTP versus ICA and fraction flow reserve (FFR) [35].
The CORE320 study is a prospective, multicenter, multinational study which deals with the diagnostic performance of 320-MDCT for detecting CHD including the accuracy of a combined CTCA and CTP protocol compared to ICA and SPECT as the reference for the detection of flow-limiting coronary artery disease [36]. CTCA and CTP versus CTCA alone lead to an increase in specificity (54 % to 73 %) and accuracy (69 % to 75 %) in patients with known and unknown CHD.
The median radiation dose exposure of CCTA combined with CTP was 8.47 mSv (CTA: 3.16 mSv, CTP: 5.31 mSv), whereas the radiation exposure of the reference standard SPECT was 9.75 mSv [37].
Kawai et al. analyzed CTCA and stress-rest myocardial perfusion (SPECT) in 204 patients after CABG surgery to calculate UCTs and the summed rest score (calculated out of segmental perfusion scores during stress and rest) [38]. UCTs and the summed rest score in combination are very helpful for risk stratification in patients after CABG surgery.
To our knowledge, there are no published studies concerning CTP of patients after CABG. The fact that further improvements in CT technology have the potential to reduce radiation dose exposure will hopefully help to bring CT perfusion measurements into the clinical routine, especially in cardiac imaging to detect myocardial ischemia but as well in oncologic imaging to assess tumor vascularization before and after chemotherapy.
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Limitations
The present study has some limitations. We have to exclude some studies because these studies did not publish absolute numbers of true-positive, true-negative, false-positive and false-negative results or did not allow calculation of these values.
Only 7 out of 13 studies evaluated native coronary arteries. Two studies did not differentiate between distal runoffs and non-grafted coronary arteries, two publications either report distal runoffs or non-grafted coronary arteries and three publications distinguish between distal runoffs and non-grafted arteries. Furthermore, more than half of the studies used segment-based analysis compared to artery-based analysis so that diagnostic performance is hard to compare in this heterogeneous group of studies.
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Summary
MD-CTA still offers high diagnostic accuracy in the evaluation of coronary artery bypass grafts, which has been unchanged despite the implementation of newer scanner generations. The most substantial benefit of the newest CT scanner (64 slices and beyond) is a remarkable reduction of radiation dose exposure. Pooled diagnostic quality of the evaluated studies did not change compared with previous studies performed on 64-MDCT. One of the two studies using 256-slice and 320-slice CT reached excellent values for sensitivity and NPV (97 % and 99.8 %, respectively) as well as the lowest radiation dose exposure (2.4 mSv) [16].
The challenge of assessing CABG in the coming years will be a further reduction of radiation dose while maintaining excellent diagnostic accuracy as well as an improvement in diagnostic accuracy in the assessment of native coronary arteries, possibly by combining MD-CTA with myocardial perfusion measurements.
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No conflict of interest has been declared by the author(s).
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References
- 1 Nichols M, Townsend N, Luengo-Fernandez R. et al. European Cardiovascular Disease Statistics 2012. European Heart Network, Brussels, European Society of Cardiology, Sophia Antipolis; 2012
- 2 Deutsche Herzstiftung e.V., Deutsche Gesellschaft für Kardiologie – Herz- und Kreislaufforschung e.V., Deutsche Gesellschaft für Thorax-, Herz-, und Gefäßchirurgie e.V., Deutsche Gesellschaft für Pädiatrische Kardiologie e.V. 26. Deutscher Herzbericht 2014.
- 3 Go AS, Mozaffarian D, Roger VL. et al. Heart disease and stroke statistics-2013 update: a report from the American Heart Association. Circulation 2013; 127: e6-e245
- 4 Patel MR, Dehmer GJ, Hirshfeld JW. et al. ACCF/SCAI/STS/AATS/AHA/ASNC/HFSA/SCCT 2012 Appropriate use criteria for coronary revascularization focused update: a report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, Society for Cardiovascular Angiography and Interventions, Society of Thoracic Surgeons, American Association for Thoracic Surgery, American Heart Association, American Society of Nuclear Cardiology, and the Society of Cardiovascular Computed Tomography. J Am Coll Cardiol 2012; 59: 857-881
- 5 Mohr FW, Morice MC, Kappetein AP. et al. Coronary artery bypass graft surgery versus percutaneous coronary intervention in patients with three-vessel disease and left main coronary disease: 5-year follow-up of the randomised, clinical SYNTAX trial. Lancet 2013; 381: 629-638
- 6 Green GE. Internal mammary artery-to-coronary artery anastomosis. Three-year experience with 165 patients. Ann Thorac Surg 1972; 14: 260-271
- 7 Barner HB. Conduits for coronary bypass: internal thoracic artery. The Korean journal of thoracic and cardiovascular surgery 2012; 45: 351-367
- 8 Tatoulis J, Buxton BF, Fuller JA. The right internal thoracic artery: the forgotten conduit – 5766 patients and 991 angiograms. Ann Thorac Surg 2011; 92: 9-15 ; discussion 15–17
- 9 Tan ES, van der Meer J, Jan de Kam P. et al. Worse clinical outcome but similar graft patency in women versus men one year after coronary artery bypass graft surgery owing to an excess of exposed risk factors in women. CABADAS. Research Group of the Interuniversity Cardiology Institute of The Netherlands. Coronary Artery Bypass graft occlusion by Aspirin, Dipyridamole and Acenocoumarol/phenoprocoumon Study. J Am Coll Cardiol 1999; 34: 1760-1768
- 10 Fitzgibbon GM, Kafka HP, Leach AJ. et al. Coronary bypass graft fate and patient outcome: angiographic follow-up of 5065 grafts related to survival and reoperation in 1388 patients during 25 years. J Am Coll Cardiol 1996; 28: 616-626
- 11 Kim FY, Marhefka G, Ruggiero NJ. et al. Saphenous vein graft disease: review of pathophysiology, prevention, and treatment. Cardiology in review 2013; 21: 101-109
- 12 Athanasiou T, Saso S, Rao C. et al. Radial artery versus saphenous vein conduits for coronary artery bypass surgery: forty years of competition – which conduit offers better patency? A systematic review and meta-analysis. Eur J Cardiothorac Surg 2010; 40: 208-220
- 13 Chow BJ, Ahmed O, Small G. et al. Prognostic value of CT angiography in coronary bypass patients. JACC Cardiovasc Imaging 2011; 4: 496-502
- 14 Hamon M, Lepage O, Malagutti P. et al. Diagnostic performance of 16- and 64-section spiral CT for coronary artery bypass graft assessment: meta-analysis. Radiology 2008; 247: 679-686
- 15 Weustink AC, Nieman K, Pugliese F. et al. Diagnostic accuracy of computed tomography angiography in patients after bypass grafting: comparison with invasive coronary angiography. JACC Cardiovasc Imaging 2009; 2: 816-824
- 16 Yuceler Z, Kantarci M, Yuce I. et al. Follow-up of coronary artery bypass graft patency: diagnostic efficiency of high-pitch dual-source 256-slice MDCT findings. Journal of computer assisted tomography 2014; 38: 61-66
- 17 Andreini D, Pontone G, Mushtaq S. et al. Diagnostic performance of two types of low radiation exposure protocol for prospective ECG-triggering multidetector computed tomography angiography in assessment of coronary artery bypass graft. Int J Cardiol 2011; 157: 63-69
- 18 Sahiner L, Canpolat U, Yorgun H. et al. Diagnostic accuracy of dual-source 64-slice multidetector computed tomography in evaluation of coronary artery bypass grafts. J Investig Med 2012; 60: 1180-1185
- 19 de Graaf FR, van Velzen JE, Witkowska AJ. et al. Diagnostic performance of 320-slice multidetector computed tomography coronary angiography in patients after coronary artery bypass grafting. Eur Radiol 21: 2285-2296
- 20 Sahiner L, Canpolat U, Aytemir K. et al. Diagnostic accuracy of 16- versus 64-slice multidetector computed tomography angiography in the evaluation of coronary artery bypass grafts: a comparative study. Interact Cardiovasc Thorac Surg 2012; 15: 847-853
- 21 Chan M, Ridley L, Dunn DJ. et al. A Systematic review and meta-analysis of multidetector computed tomography in the assessment of coronary artery bypass grafts. J Cardiol 2016; 221: 898-905
- 22 Alkadhi H. Radiation dose of cardiac CT – what is the evidence?. Eur Radiol 2009; 19: 1311-1315
- 23 Hou Y, Xu S, Guo W. et al. The optimal dose reduction level using iterative reconstruction with prospective ECG-triggered coronary CTA using 256-slice MDCT. Eur J Radiol 2012; 81: 3905-3911
- 24 Goetti R, Leschka S, Baumuller S. et al. Low dose high-pitch spiral acquisition 128-slice dual-source computed tomography for the evaluation of coronary artery bypass graft patency. Invest Radiol 45: 324-330
- 25 Menke J, Unterberg-Buchwald C, Staab W. et al. Head-to-head comparison of prospectively triggered vs retrospectively gated coronary computed tomography angiography: Meta-analysis of diagnostic accuracy, image quality, and radiation dose. Am Heart J 2013; 165: 154-163
- 26 Muenzel D, Noel PB, Dorn F. et al. Step and shoot coronary CT angiography using 256-slice CT: effect of heart rate and heart rate variability on image quality. Eur Radiol 21: 2277-2284
- 27 Kolluri R, Fowler B, Nandish S. Vascular access complications: diagnosis and management. Current treatment options in cardiovascular medicine 2013; 15: 173-187
- 28 Nathan S, Rao SV. Radial versus femoral access for percutaneous coronary intervention: implications for vascular complications and bleeding. Current cardiology reports 2012; 14: 502-509
- 29 Khan NU, Yonan N. Does preoperative computed tomography reduce the risks associated with re-do cardiac surgery?. Interact Cardiovasc Thorac Surg 2009; 9: 119-123
- 30 Pesenti-Rossi D, Baron N, Georges JL. et al. Assessment of coronary bypass graft patency by first-line multi-detector computed tomography. Annales de cardiologie et d'angeiologie 2014; 63: 284-292
- 31 Taylor AJ, Cerqueira M, Hodgson JM. et al. ACCF/SCCT/ACR/AHA/ASE/ASNC/NASCI/SCAI/SCMR 2010 appropriate use criteria for cardiac computed tomography. A report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, the Society of Cardiovascular Computed Tomography, the American College of Radiology, the American Heart Association, the American Society of Echocardiography, the American Society of Nuclear Cardiology, the North American Society for Cardiovascular Imaging, the Society for Cardiovascular Angiography and Interventions, and the Society for Cardiovascular Magnetic Resonance. J Am Coll Cardiol 56: 1864-1894
- 32 Achenbach S, Barkhausen J, Beer M. et al. Consensus recommendations of the German Radiology Society (DRG), the German Cardiac Society (DGK) and the German Society for Pediatric Cardiology (DGPK) on the use of cardiac imaging with computed tomography and magnetic resonance imaging. Rofo 2012; 184: 345-368
- 33 Bamberg F, Becker A, Schwarz F. et al. Detection of hemodynamically significant coronary artery stenosis: incremental diagnostic value of dynamic CT-based myocardial perfusion imaging. Radiology 260: 689-698
- 34 Okada DR, Ghoshhajra BB, Blankstein R. et al. Direct comparison of rest and adenosine stress myocardial perfusion CT with rest and stress SPECT. J Nucl Cardiol 2010; 17: 27-37
- 35 Tashakkor AY, Nicolaou S, Leipsic J. et al. The emerging role of cardiac computed tomography for the assessment of coronary perfusion: a systematic review and meta-analysis. Can J Cardiol 2012; 28: 413-422
- 36 Magalhaes TA, Kishi S, George RT. et al. Combined coronary angiography and myocardial perfusion by computed tomography in the identification of flow-limiting stenosis – The CORE320 study: An integrated analysis of CT coronary angiography and myocardial perfusion. J Cardiovasc Comput Tomogr 2015; 9: 438-445
- 37 Yoneyama K, Vavere AL, Cerci R. et al. Influence of image acquisition settings on radiation dose and image quality in coronary angiography by 320-detector volume computed tomography: the CORE320 pilot experience. Heart international 2012; 7: e11
- 38 Kawai H, Sarai M, Motoyama S. et al. A combination of anatomical and functional evaluations improves the prediction of cardiac event in patients with coronary artery bypass. BMJ Open 2013; 3: e003474
- 39 Feuchtner GM, Schachner T, Bonatti J. et al. Diagnostic performance of 64-slice computed tomography in evaluation of coronary artery bypass grafts. Am J Roentgenol 2007; 189: 574-580
- 40 Gorantla R, Murthy JS, Muralidharan TR. et al. Diagnostic accuracy of 64-slice multidetector computed tomography in evaluation of post-coronary artery bypass grafts in correlation with invasive coronary angiography. Indian Heart J 2012; 64: 254-260
- 41 Lee JH, Chun EJ, Choi SI. et al. Prospective versus retrospective ECG-gated 64-detector coronary CT angiography for evaluation of coronary artery bypass graft patency: comparison of image quality, radiation dose and diagnostic accuracy. Int J Cardiovasc Imaging 2011; 27: 657-667
- 42 Nazeri I, Shahabi P, Tehrai M. et al. Assessment of patients after coronary artery bypass grafting using 64-slice computed tomography. Am J Cardiol 2009; 103: 667-673
- 43 Onuma Y, Tanabe K, Chihara R. et al. Evaluation of coronary artery bypass grafts and native coronary arteries using 64-slice multidetector computed tomography. Am Heart J 2007; 154: 519-526
- 44 Romagnoli A, Patrei A, Mancini A. et al. Diagnostic accuracy of 64-slice CT in evaluating coronary artery bypass grafts and of the native coronary arteries. Radiol Med 2010; 115: 1167-1178
- 45 Tochii M, Takagi Y, Anno H. et al. Accuracy of 64-slice multidetector computed tomography for diseased coronary artery graft detection. Ann Thorac Surg 2010; 89: 1906-1911
Correspondence
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References
- 1 Nichols M, Townsend N, Luengo-Fernandez R. et al. European Cardiovascular Disease Statistics 2012. European Heart Network, Brussels, European Society of Cardiology, Sophia Antipolis; 2012
- 2 Deutsche Herzstiftung e.V., Deutsche Gesellschaft für Kardiologie – Herz- und Kreislaufforschung e.V., Deutsche Gesellschaft für Thorax-, Herz-, und Gefäßchirurgie e.V., Deutsche Gesellschaft für Pädiatrische Kardiologie e.V. 26. Deutscher Herzbericht 2014.
- 3 Go AS, Mozaffarian D, Roger VL. et al. Heart disease and stroke statistics-2013 update: a report from the American Heart Association. Circulation 2013; 127: e6-e245
- 4 Patel MR, Dehmer GJ, Hirshfeld JW. et al. ACCF/SCAI/STS/AATS/AHA/ASNC/HFSA/SCCT 2012 Appropriate use criteria for coronary revascularization focused update: a report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, Society for Cardiovascular Angiography and Interventions, Society of Thoracic Surgeons, American Association for Thoracic Surgery, American Heart Association, American Society of Nuclear Cardiology, and the Society of Cardiovascular Computed Tomography. J Am Coll Cardiol 2012; 59: 857-881
- 5 Mohr FW, Morice MC, Kappetein AP. et al. Coronary artery bypass graft surgery versus percutaneous coronary intervention in patients with three-vessel disease and left main coronary disease: 5-year follow-up of the randomised, clinical SYNTAX trial. Lancet 2013; 381: 629-638
- 6 Green GE. Internal mammary artery-to-coronary artery anastomosis. Three-year experience with 165 patients. Ann Thorac Surg 1972; 14: 260-271
- 7 Barner HB. Conduits for coronary bypass: internal thoracic artery. The Korean journal of thoracic and cardiovascular surgery 2012; 45: 351-367
- 8 Tatoulis J, Buxton BF, Fuller JA. The right internal thoracic artery: the forgotten conduit – 5766 patients and 991 angiograms. Ann Thorac Surg 2011; 92: 9-15 ; discussion 15–17
- 9 Tan ES, van der Meer J, Jan de Kam P. et al. Worse clinical outcome but similar graft patency in women versus men one year after coronary artery bypass graft surgery owing to an excess of exposed risk factors in women. CABADAS. Research Group of the Interuniversity Cardiology Institute of The Netherlands. Coronary Artery Bypass graft occlusion by Aspirin, Dipyridamole and Acenocoumarol/phenoprocoumon Study. J Am Coll Cardiol 1999; 34: 1760-1768
- 10 Fitzgibbon GM, Kafka HP, Leach AJ. et al. Coronary bypass graft fate and patient outcome: angiographic follow-up of 5065 grafts related to survival and reoperation in 1388 patients during 25 years. J Am Coll Cardiol 1996; 28: 616-626
- 11 Kim FY, Marhefka G, Ruggiero NJ. et al. Saphenous vein graft disease: review of pathophysiology, prevention, and treatment. Cardiology in review 2013; 21: 101-109
- 12 Athanasiou T, Saso S, Rao C. et al. Radial artery versus saphenous vein conduits for coronary artery bypass surgery: forty years of competition – which conduit offers better patency? A systematic review and meta-analysis. Eur J Cardiothorac Surg 2010; 40: 208-220
- 13 Chow BJ, Ahmed O, Small G. et al. Prognostic value of CT angiography in coronary bypass patients. JACC Cardiovasc Imaging 2011; 4: 496-502
- 14 Hamon M, Lepage O, Malagutti P. et al. Diagnostic performance of 16- and 64-section spiral CT for coronary artery bypass graft assessment: meta-analysis. Radiology 2008; 247: 679-686
- 15 Weustink AC, Nieman K, Pugliese F. et al. Diagnostic accuracy of computed tomography angiography in patients after bypass grafting: comparison with invasive coronary angiography. JACC Cardiovasc Imaging 2009; 2: 816-824
- 16 Yuceler Z, Kantarci M, Yuce I. et al. Follow-up of coronary artery bypass graft patency: diagnostic efficiency of high-pitch dual-source 256-slice MDCT findings. Journal of computer assisted tomography 2014; 38: 61-66
- 17 Andreini D, Pontone G, Mushtaq S. et al. Diagnostic performance of two types of low radiation exposure protocol for prospective ECG-triggering multidetector computed tomography angiography in assessment of coronary artery bypass graft. Int J Cardiol 2011; 157: 63-69
- 18 Sahiner L, Canpolat U, Yorgun H. et al. Diagnostic accuracy of dual-source 64-slice multidetector computed tomography in evaluation of coronary artery bypass grafts. J Investig Med 2012; 60: 1180-1185
- 19 de Graaf FR, van Velzen JE, Witkowska AJ. et al. Diagnostic performance of 320-slice multidetector computed tomography coronary angiography in patients after coronary artery bypass grafting. Eur Radiol 21: 2285-2296
- 20 Sahiner L, Canpolat U, Aytemir K. et al. Diagnostic accuracy of 16- versus 64-slice multidetector computed tomography angiography in the evaluation of coronary artery bypass grafts: a comparative study. Interact Cardiovasc Thorac Surg 2012; 15: 847-853
- 21 Chan M, Ridley L, Dunn DJ. et al. A Systematic review and meta-analysis of multidetector computed tomography in the assessment of coronary artery bypass grafts. J Cardiol 2016; 221: 898-905
- 22 Alkadhi H. Radiation dose of cardiac CT – what is the evidence?. Eur Radiol 2009; 19: 1311-1315
- 23 Hou Y, Xu S, Guo W. et al. The optimal dose reduction level using iterative reconstruction with prospective ECG-triggered coronary CTA using 256-slice MDCT. Eur J Radiol 2012; 81: 3905-3911
- 24 Goetti R, Leschka S, Baumuller S. et al. Low dose high-pitch spiral acquisition 128-slice dual-source computed tomography for the evaluation of coronary artery bypass graft patency. Invest Radiol 45: 324-330
- 25 Menke J, Unterberg-Buchwald C, Staab W. et al. Head-to-head comparison of prospectively triggered vs retrospectively gated coronary computed tomography angiography: Meta-analysis of diagnostic accuracy, image quality, and radiation dose. Am Heart J 2013; 165: 154-163
- 26 Muenzel D, Noel PB, Dorn F. et al. Step and shoot coronary CT angiography using 256-slice CT: effect of heart rate and heart rate variability on image quality. Eur Radiol 21: 2277-2284
- 27 Kolluri R, Fowler B, Nandish S. Vascular access complications: diagnosis and management. Current treatment options in cardiovascular medicine 2013; 15: 173-187
- 28 Nathan S, Rao SV. Radial versus femoral access for percutaneous coronary intervention: implications for vascular complications and bleeding. Current cardiology reports 2012; 14: 502-509
- 29 Khan NU, Yonan N. Does preoperative computed tomography reduce the risks associated with re-do cardiac surgery?. Interact Cardiovasc Thorac Surg 2009; 9: 119-123
- 30 Pesenti-Rossi D, Baron N, Georges JL. et al. Assessment of coronary bypass graft patency by first-line multi-detector computed tomography. Annales de cardiologie et d'angeiologie 2014; 63: 284-292
- 31 Taylor AJ, Cerqueira M, Hodgson JM. et al. ACCF/SCCT/ACR/AHA/ASE/ASNC/NASCI/SCAI/SCMR 2010 appropriate use criteria for cardiac computed tomography. A report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, the Society of Cardiovascular Computed Tomography, the American College of Radiology, the American Heart Association, the American Society of Echocardiography, the American Society of Nuclear Cardiology, the North American Society for Cardiovascular Imaging, the Society for Cardiovascular Angiography and Interventions, and the Society for Cardiovascular Magnetic Resonance. J Am Coll Cardiol 56: 1864-1894
- 32 Achenbach S, Barkhausen J, Beer M. et al. Consensus recommendations of the German Radiology Society (DRG), the German Cardiac Society (DGK) and the German Society for Pediatric Cardiology (DGPK) on the use of cardiac imaging with computed tomography and magnetic resonance imaging. Rofo 2012; 184: 345-368
- 33 Bamberg F, Becker A, Schwarz F. et al. Detection of hemodynamically significant coronary artery stenosis: incremental diagnostic value of dynamic CT-based myocardial perfusion imaging. Radiology 260: 689-698
- 34 Okada DR, Ghoshhajra BB, Blankstein R. et al. Direct comparison of rest and adenosine stress myocardial perfusion CT with rest and stress SPECT. J Nucl Cardiol 2010; 17: 27-37
- 35 Tashakkor AY, Nicolaou S, Leipsic J. et al. The emerging role of cardiac computed tomography for the assessment of coronary perfusion: a systematic review and meta-analysis. Can J Cardiol 2012; 28: 413-422
- 36 Magalhaes TA, Kishi S, George RT. et al. Combined coronary angiography and myocardial perfusion by computed tomography in the identification of flow-limiting stenosis – The CORE320 study: An integrated analysis of CT coronary angiography and myocardial perfusion. J Cardiovasc Comput Tomogr 2015; 9: 438-445
- 37 Yoneyama K, Vavere AL, Cerci R. et al. Influence of image acquisition settings on radiation dose and image quality in coronary angiography by 320-detector volume computed tomography: the CORE320 pilot experience. Heart international 2012; 7: e11
- 38 Kawai H, Sarai M, Motoyama S. et al. A combination of anatomical and functional evaluations improves the prediction of cardiac event in patients with coronary artery bypass. BMJ Open 2013; 3: e003474
- 39 Feuchtner GM, Schachner T, Bonatti J. et al. Diagnostic performance of 64-slice computed tomography in evaluation of coronary artery bypass grafts. Am J Roentgenol 2007; 189: 574-580
- 40 Gorantla R, Murthy JS, Muralidharan TR. et al. Diagnostic accuracy of 64-slice multidetector computed tomography in evaluation of post-coronary artery bypass grafts in correlation with invasive coronary angiography. Indian Heart J 2012; 64: 254-260
- 41 Lee JH, Chun EJ, Choi SI. et al. Prospective versus retrospective ECG-gated 64-detector coronary CT angiography for evaluation of coronary artery bypass graft patency: comparison of image quality, radiation dose and diagnostic accuracy. Int J Cardiovasc Imaging 2011; 27: 657-667
- 42 Nazeri I, Shahabi P, Tehrai M. et al. Assessment of patients after coronary artery bypass grafting using 64-slice computed tomography. Am J Cardiol 2009; 103: 667-673
- 43 Onuma Y, Tanabe K, Chihara R. et al. Evaluation of coronary artery bypass grafts and native coronary arteries using 64-slice multidetector computed tomography. Am Heart J 2007; 154: 519-526
- 44 Romagnoli A, Patrei A, Mancini A. et al. Diagnostic accuracy of 64-slice CT in evaluating coronary artery bypass grafts and of the native coronary arteries. Radiol Med 2010; 115: 1167-1178
- 45 Tochii M, Takagi Y, Anno H. et al. Accuracy of 64-slice multidetector computed tomography for diseased coronary artery graft detection. Ann Thorac Surg 2010; 89: 1906-1911