Curr Radiol Rep (2015) 3:38 DOI 10.1007/s40134-015-0120-1
ADVANCES IN CARDIOVASCULAR IMAGING (A BIERHALS, SECTION EDITOR)
Utility of Coronary CT Angiography in the Assessment of Acute Chest Pain in the Emergency Department: Current Perspectives Alan Ropp1 • Cheng Ting Lin2 • Charles S. White1 • Jean Jeudy1
Published online: 28 August 2015 Springer Science+Business Media New York 2015
Abstract Acute chest pain remains a highly prevalent complaint in the emergency setting with an extensive differential. Cardiac CTA has emerged as an effective tool aiding in rapid triage of these patients. Due to its excellent negative predictive value, new guidelines recommend CCTA for the purpose of excluding acute coronary syndrome in low- to intermediate-risk patients. Research continues to validate CCTA’s application for this purpose, its appropriateness compared to other available exams, and explore emerging capabilities of CCTA as a noninvasive method of evaluating coronary artery disease in the setting of acute chest pain. Keywords Acute coronary syndrome Cardiac CT angiography Cardiac CT Chest pain Emergency department Angina
diagnosed with acute coronary syndrome (ACS). Because of this, there is a strong demand for safe, cost effective, rapid, and reliable methods of triaging these patients. The standard ED evaluation of patients presenting with ACS involves electrocardiography and trending of cardiac biomarkers, as well as a choice of several different imaging modalities with various risks and benefits. These include echocardiography, nuclear medicine myocardial perfusion imaging, invasive coronary angiography (ICA), and coronary CT angiography (CCTA) [2]. In the setting of ACS, CCTA is most useful for non-invasively identifying patients who may be safely discharged after exclusion of coronary artery disease (CAD) by noting a lack of coronary artery calcifications.
Evolution of Cardiac CTA Introduction Acute chest pain is one of the most frequent etiologies for presentation to the emergency department (ED), accounting for 5.5 million ED visits per year in the United States [1]. Of patients who present, only 13 % are ultimately
This article is part of the Topical Collection on Advances in Cardiovascular Imaging. & Jean Jeudy
[email protected] 1
University of Maryland School of Medicine, Cardiothoracic Imaging, Department of Diagnostic Radiology & Nuclear Medicine, University of Maryland Medical Center, 22 S Greene Street, Baltimore, MD 21201, USA
2
Department of Radiology, Johns Hopkins University, Baltimore, MD, USA
The initial purpose of CCTA was to non-invasively riskstratify patients with ACS depending on the severity of coronary artery calcification. Coronary calcification can be quantitatively assessed using a standardized method, known as Agatston scoring [3]. Strengths of calcium scoring include good sensitivity, negative predictive value, and ease of acquisition with any multi-detector CT (MDCT) scanner [4– 6]. A well-recognized limitation of calcium scoring is the failure to identify significant non-calcified stenosis, as these will result in a negative calcium score despite the presence of potentially significant pathology [7, 8]. Advancements in MDCT technology have allowed the rapid development and implementation of CCTA. Modern scanners are capable of imaging the coronary arteries with excellent spatial resolution, typically in the range of 0.5–0.625 mm. Scan speeds of an average of less than 10 s may be obtained with potential scan speeds of \1 s. After
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the widespread implementation of CCTA, substantial evidence has accumulated supporting its use in the evaluation of ED patients with atypical or nonspecific chest pain (Fig. 1).
Evidence A number of multicenter trials have compared the diagnostic accuracy of CCTA with ICA as the gold standard for evaluating symptomatic outpatients with chest pain and found a very high sensitivity ([95 %) and high negative predictive value (83–99 %) for excluding significant CAD [9, 10, 11••]. Specificity and positive predictive value are moderate to high [12–14]. Increasing evidence supports the use of CCTA for the purpose of excluding CAD in low- to intermediate-risk populations presenting with acute chest pain. If CCTA demonstrates no significant coronary artery calcifications, ACS may be reliably excluded. The CCTA Evaluation for Clinical Outcomes: An International Multicenter Registry (CONFIRM) trial was a multinational prospective observational trial including 27,000 patients undergoing CCTA. The study included symptomatic patients with suspected CAD, known CAD, and asymptomatic patients. These patients received CCTA as part of their initial workup and were followed up for the occurrence of major adverse cardiovascular events. This trial confirmed that the absence of coronary atherosclerosis on CCTA is associated with an excellent prognosis, underscoring the excellent negative predictive value of CCTA. The strength of this evidence points the potential of using CTA to identify patients with a low likelihood of coronary disease who may be safely discharged from the ED without further workup. The all-cause mortality in this group was 0.65 % after a mean follow-up of 22.5 months. Mortality also correlated with CAD severity, as measured by CCTA. Patients with non-obstructive CAD experienced 1.99 % mortality, while patients with high-risk obstruction experienced 4.95 % mortality. The study also revealed a positive correlation between the number of vessels involved and all-cause mortality, with the worst outcomes seen in patients with three-vessel or left main disease. Of note, relatively high rates of non-obstructive and obstructive CAD were seen in patients with a calcium score of zero. This finding was associated with an increased number of cardiac events [15]. Clinical Trials on Acute Chest Pain Several large randomized multicenter trials have assessed the specific use of CCTA for patients presenting to the ED with acute chest pain (Table 1). The CT-STAT trial was a 699 patient randomized clinical trial comparing CCTA to
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Fig. 1 a–c History: 67-year-old male with history of hypertension and hyperlipidemia, presented to the ED with acute chest pain. Axial and coronary CTA (a, b) demonstrate multivessel disease including high grade stenosis of the mid-RCA. Findings were confirmed on cardiac catheterization (c), and patient subsequently underwent coronary artery bypass grafting
MPI as the initial noninvasive test performed before ICA. The results generally favored the use of CCTA for this purpose in low- to intermediate-risk patients presenting with acute chest pain. Risk stratification for the trial was performed using the thrombosis in myocardial infarction (TIMI) score [16]. The standard workup included ECG and troponins to distinguish STEMI, NSTEMI, and UA.
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STEMI patients were treated with urgent revascularization. NSTEMI or UA patients underwent risk stratification, with subsequent treatment and workup based on TIMI score. Several potential benefits of CCTA over MPI demonstrated by the study included a 54 % reduction in time to diagnosis (2.9 vs. 6.3 h), decreased total ED cost of care by 38 % ($2137 vs. $3458), and lower effective radiation doses (11.5 vs. 12.8 mSv). There was minimal difference in major adverse cardiac events (MACEs) between the two groups (0.8 vs. 0.4 %) [17•]. One potential weakness identified by the trial was the relatively low specificity of CCTA (64–90 %). Patients with 50–69 % vessel stenosis on CCTA were considered equivocal and therefore required further evaluation with MPI before revascularization. Two other trials, ROMICAT II and ACRIN-PA, provided significant additional evidence supporting the use of CCTA in the evaluation of low- to intermediate-risk ED patients presenting with chest pain [18]. Notably, these trials reinforced the use of CCTA as a reliable tool for excluding CAD, thus allowing discharge from the ED with a very low risk of MACEs. This allowed a significant reduction in time to diagnosis and total cost of care [18]. The ROMICAT II trial randomized 1000 patients to a either a workup incorporating CCTA or standard ED evaluation. The results of this study confirmed the reduced time to discharge found in the CT-STAT trial. Fifty-percent
of patients evaluated with CCTA were discharged within 8.6 h compared with 10 % in the standard evaluation group. If the patients were diagnosed with ACS, the length of stay was similar in both groups. Neither group recorded any undetected ACS. One potential weakness identified in the CCTA group was a higher cumulative radiation exposure. However, it was noted that much of this increase in dose can be mitigated by the use of increasingly available advanced 128-slice dual-source CT. Patients who underwent CCTA with a scanner of this type received a lower cumulative radiation exposure (6.2 mSv) compared with 4.7 mSv in the standard ED evaluation group. Total cost of care was similar across both the groups. Overall, patients randomized to a workup incorporating CCTA demonstrated a higher negative predictive value at a similar cost of care but at the expense of higher cumulative radiation doses. The third major trial, the ACRIN-PA TRIAL published in 2012, also compared an acute chest pain workup utilizing CCTA versus a standard emergency department workup [19••]. 1370 patients met the inclusion criteria for the trial by presenting with chest pain and a low to intermediate risk of ACS by TIMI score. As with the ROMICAT II trial, patients evaluated with CCTA were more likely to be discharged (50 vs. 23 %) and experienced a shorter average length of stay. Patients undergoing CCTA
Table 1 Randomized controlled trials (RCTs) evaluating the use of CCTA in the diagnosis of acute chest pain in the emergency department RCT
CT-STAT
ROMICAT II
ACRIN
Meta analysisa
Authors
Goldstein et al. [17•]
Hoffman et al. [31•]
Litt et al. [19••]
Hulten et al. [11••]
Year
2011
2012
2012
2013
CT scanner
64-MDCT?
64-MDCT?
64-MDCT?
–
Patients (n)
699
1000
1370
1397 control; 1869 CCTA
Follow-up (month)
6
1
1
Study groups
Control
CCTA
Control
CCTA
Control
CCTA
CCTA
n
338
361
499
501
462
908
1869
Time to diagnosis (h)
6.2
2.9
21
5.8
18.7
10.4
SOC [ CCTA
PTS discharged from ED (%)
80
73
12
47
23
50
SOC [ CCTA
ED cost ($)
3458
2137
2566
2101
–
–
Reduced 18–38 %
Prevalence of MI (%)
1.5
0.3
3.0
2.0
1.0
1.0
1.0
Acute deaths (%)
0
0
0
0
0
0
0
PTS undergoing coronary revascularization after CCTA (%)
0.3
2.2
2.8
4.2
6.9
2.64
2.6 % control versus 4.1 % CCTA (p = 0.004)
Events
CCTA cardiac computed tomography angiography, ED emergency department, MI myocardial infarction, PTS patients, SOC standard of care ACRIN-PA American College of Radiology Imaging Network of Pennsylvania, CT-STAT Coronary Computed Tomographic Angiography for Systematic Triage of Acute Chest Pain Patients to Treatment trial, ROMICAT II Rule out Myocardial Ischemia/Infarction Using Computer Assisted Tomography II trial a
Pooled analysis of ED length of stay and cost assessments were not performed due to the heterogeneity in study design and definitions of parameters. However, all RCTs demonstrate the trend of lower length of stay and decreased ED costs for the use of CCTA compared to standard of care
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were less likely to have a negative ICA, but there was no difference in the numbers of repeat ED visits, hospitalization rate, or cardiologist office visits. The authors of the study concluded that CCTA can be performed with an average radiation dose lower than MPI and reaffirmed the negative predictive value of CCTA allowing for safe discharge and thus reduced average length of stay. Furthermore, the use of CCTA allows for earlier identification of CAD, which may provide opportunities for the use of preventative therapies that may improve patient outcomes. Several studies have evaluated patients with negative CCTA and the subsequent risk of MACEs. These studies have found that patients with a negative CCTA have a very low risk of MACE for 1–2 years and probably longer. Specifically, patients with a negative CCTA had a \1 % rate of MACE [9] and could be considered ‘‘risk free’’ for at least 2 years [10]. Patients with regional wall motion abnormalities had the highest risk of MACE [10]. A meta-analysis of the CT-STAT, ACRIN-PA, ROMICAT II trials, and an earlier trial by Goldstein et al. was performed by Hulten et al. and provided valuable information regarding the implementation of CCTA. Their findings reaffirmed the safety and effectiveness of CCTA for evaluating low- to intermediate-risk ED patients presenting with chest pain, particularly its strong negative predictive value. Accordingly, the ED length of stay was significantly reduced. The use of CCTA also increased the number of patients undergoing ICA and revascularization by 2 %, identifying additional patients with potentially significant coronary disease that would have otherwise gone undetected. This translates to 1 additional patient receiving revascularization for every 50 patients undergoing CCTA. Whether this will result in better outcomes remains unclear, as the number of deaths and subsequent MIs in the study group were no different when compared with usual care [11••]. Additional large randomized clinical trials are underway which may provide more powerful data related to the use of CCTA in the ED, most notably, the Better Evaluation of Acute Chest Pain with Computed Tomography Angiography (BEACON) study and the study Comparing CT Scan and Stress Test in Patients with Known Coronary Artery Disease Hospitalized for Chest Pain (PROSPECT-CAD). The BEACON study is a randomized controlled trial evaluating the value of CCTA in 500 patients with suspected ACS in the ED. The goal of the study is to evaluate successful discharge rate of patients undergoing CCTA as well as the positive predictive value of severe CAD as diagnosed by CCTA. The PROSPECT-CAD study will evaluate patients who have been hospitalized for acute chest pain and will compare CCTA with myocardial perfusion imaging to determine which test is superior for identifying patients with severe CAD requiring revascularization.
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Guidelines Multiple organizations have published guidelines regarding the appropriate use of CCTA in symptomatic patients. Based on current evidence, CCTA is considered appropriate for the evaluation of low to intermediate risk patients presenting with acute chest pain and normal or equivocal ECG and troponin levels. The protocol for a CCTA should be limited to the heart; however, when the chest pain is atypical and the likelihood of pulmonary embolism or aortic dissection is considered significant, a ‘‘triple ruleout’’ scan may be considered. This is a scan with a larger field of view and contrast timing optimized to evaluate the aorta and the pulmonary arterial vasculature in addition to the coronary arteries. In 2010 numerous societies, committees and other organizations with interests related to the management of ACS, heart disease, and cardiothoracic radiology released a consensus document defining the appropriate use criteria for CCTA [10]. The document classifies CCTA as ‘‘appropriate’’ for evaluation of low to intermediate risk patients with ‘‘acute symptoms suspicious for ACS’’ [20•]. The document defines low- to intermediate-risk patient as an having approximately 10–20 % absolute risk of coronary heart disease over 10 years [20•]. In 2012, the ACR published its own appropriateness criteria for the evaluation of a patient presenting with acute nonspecific chest pain at low probability of CAD. The document defined CCTA as ‘‘usually appropriate’’ in that setting [21]. MPI and ICA were rated ‘‘may be appropriate’’ and ‘‘usually not appropriate,’’ respectively. Conversely, when the pretest probability of ACS is high, CCTA has a lower rating than both MPI and ICA [21].
Implementation Scanner Technology The majority of diagnostic studies are obtained with conventional 64 slices or higher MDCT scanners located in close proximity to the ED. However, technological advances in MDCT systems and techniques allowing more optimal coronary artery imaging are becoming increasingly available. Scanners with wide detector widths (up to 256 or even 320 slices) covering up to 16 cm reduce mis-registration artifact and acquisition time. The available 320-slice MDCT scanners have superior spatial resolution (0.5 mm) and allow coverage of the entire coronary anatomy in one rotation, while the 256-slice scanners utilize double Z-sampling and provide improved temporal resolution (0.27-s rotation time). Spectral CT is another burgeoning area of innovation in cardiac imaging. Several
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dual-source 2 9 128-slice scanners are now available, offering dual- or multiple-energy acquisitions in addition to improved temporal resolution (\0.28-s rotation time). Radiation Concerns A potential disadvantage of the increase in use of CCTA is the mild but potentially significant increase in radiation dose compared with conventional workup. The ALARA principle, that the radiation dose should be ‘‘As Low As Reasonably Achievable,’’ prevails in clinical practice. The imaging community has aggressively pushed to lower effective radiation dose by optimizing acquisition protocols. The typical CCTA study delivers a dose of approximately 12 mSv [22, 23]. Because the radiation dose is proportional to the square of the tube voltage, our institutional protocol utilizes a tube potential of 100 kV in patients with BMI of less than 40 kg/m2. An increased tube voltage of 120 kV is used to preserve image quality in patients with higher BMIs. More recent advances in scanner technology and reconstruction methods have allowed drastic reductions in radiation dose. Some institutions have reported sub-milliSievert scans with ideal scanning conditions and fully optimized technique are available [24•]. Scanning techniques, such as prospective, rather than retrospective triggering can result in up to an 80 % reduction in dose [19••, 25]. Limiting the use of ‘‘triple-rule-out’’ scans to specific equivocal presentations and opting for a dedicated coronary CCTA whenever possible can also significantly reduce cumulative radiation doses in ACS workups [26]. Although ‘‘triple-rule-out’’ scans are typically higher in radiation dose compared with CCTA, diagnostic ‘‘triple rule-out’’ scans have reportedly been obtained with an effective dose as low as 1.4 mSV [27]. An additional consideration, related to radiation risk, is that patients undergoing workup for ACS tend to be older, and therefore significantly less likely to develop radiation induced malignancy. Increasing computational power has enabled the use of more advanced reconstruction algorithms than the more traditional filtered back projection. Computationally demanding algorithms such as iterative reconstruction are now being utilized. This reconstruction method provides similar image quality to the filtered back projection method, with up to 44 % dose reduction in CCTA studies [28••, 29]. Model-based iterative reconstruction (MBIR, GE Healthcare, Waukesha, Wisconsin) is one of the new algorithms which show promise and allow submillisevert doses [30].
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a significant reduction in length of stay, but whether there is a reduction in overall costs remains less clear. Three of the four studies evaluated by Hulten et al. (ACRIN-PA, CT-STAT, ROMICAT II, and Goldstein et al.) found a reduction in ED costs compared with the usual care. One recent study by Hoffman et al. demonstrated a reduction of ED costs by 18 % in patients undergoing CCTA [31•]. However, this was offset by a slight increase in the cost for hospitalized patients who underwent CCTA. Of note, some of the increased cost was due to improved detection of obstructive CAD and it remains unclear whether this increase in sensitivity translates to better outcomes. Another study by Khare et al., suggested that a triage strategy including CCTA is more cost effective than triage strategies based on other exams, such as stress echocardiography or stress ECG [32]. Overall, CCTA was more cost effective for women than men, likely due to the lower disease prevalence in women, allowing a better negative predictive value [33]. The results of the higher power and more directed trials will provide a more accurate evaluation of the cost effectiveness of CCTA in comparison to alternative exams or usual care.
Recent Considerations Plaque Characterization In addition to quantifying the degree of luminal stenosis, CCTA may also be used for qualitative plaque characterization to distinguish high-risk lesions. The napkin-ring sign defined by a combination of high-attenuation rim (fibrous plaque) and central low attenuation (necrotic lipid-rich core) is another high-risk plaque feature that is associated with ACS [34]. A study by Motoyama et al. determined that plaques with positive remodeling and low attenuation (\30 HU) should be considered high-risk lesions due to the increased risk of rupture and subsequent development of ACS [35]. Another study by Madder et al. found CCTA had good sensitivity (53–81 %) and specificity (82–95 %) for identifying evidence of plaque disruption, including plaque ulceration and dye penetration. The study also found these lesions were larger, more likely to demonstrate positive remodeling, and contained more low attenuation (fibrofatty) plaque (\50 HU) [36]. At our institution, we report non-calcified plaque and positive remodeling as significant findings. Fractional Flow Reserve
Cost Effectiveness Current evidence regarding the use of CCTA in patients presenting to the ED with acute chest pain suggests there is
Fractional flow reserve is a method used during ICA to determine the hemodynamic significance of focal coronary artery stenosis by measuring the ratio of the pressure
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proximal and distal to the lesion. FFR is considered the current gold standard for determining the need for revascularization when other findings are equivocal or indeterminate. FFR is calculated by dividing the pressure distal to the stenosis by the pressure proximal to the stenosis at maximal dilation. FFR values ranging from 0.8 to 1.0 are considered non-ischemic. FFR values \0.75 are associated with ischemia and are considered an indication for revascularization. Values between 0.75 and 0.8 are considered indeterminate [37, 38]. The CCTA correlate to FFR, often denoted FFRCT, uses computational fluid dynamics to non-invasively estimate the FFR. The determination of fractional flow reserve by anatomic computed tomography or DeFACTO trial found that incorporating FFRCT criteria into the evaluation of stenoses improves the detection of hemodynamically significant lesions. CT perfusion is another technique available for the evaluation of stenotic lesions by characterizing downstream perfusion. Based on currently available techniques, resting CT myocardial perfusion imaging is not reliable for the exclusion of ACS. In one study, CT perfusion only detected three of nine patients presenting with ACS [39]. The use of adenosine stress CT perfusion may be more useful. A study by Rochitte et al. found that combining CTA and adenosine stress CT perfusion could provide accurate diagnosis of hemodynamically significant CAD when compared to ICA and MPI [40••]. It is unclear if CCTA combined with CTP is superior to CCTA alone in the evaluation of low- to intermediate-risk patients presenting to the ED with chest pain.
Conclusions Extensive evidence derived from multiple large randomized clinical trials has confirmed the appropriateness of CCTA for the exclusion of ACS in low- to intermediaterisk ED patients presenting with acute chest pain with indeterminate ECG findings and troponin levels. Ongoing research in the potential applications of CCTA including plaque characterization, quantitative flow/perfusion analysis, and methods of dose reduction will continue to expand its role. Compliance with Ethics Guidelines Conflict of Interest Alan Ropp, Cheng Ting Lin, Charles S White, and Jean Jeudy each declare no potential conflicts of interest. Human and Animal Rights and Informed Consent This article does not contain any studies with human or animal subjects performed by any of the authors.
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References Papers of particular interest, published recently, have been highlighted as: • Of importance •• Of major importance 1. Bhuiya FA, Pitts SR, McCaig LF. Emergency department visits for chest pain and abdominal pain: United States, 1999-2008. NCHS Data Brief. 2010;43:1–8. 2. Korff S, Katus HA, Giannitsis E. Differential diagnosis of elevated troponins. Heart. 2006;92(7):987–93. 3. Agatston AS, Janowitz WR, Hildner FJ, Zusmer NR, Viamonte M, Detrano R. Quantification of coronary artery calcium using ultrafast computed tomography. J Am Coll Cardiol. 1990;15(4):827–32. 4. Georgiou D, Budoff MJ, Kaufer E, Kennedy JM, Lu B, Brundage BH. Screening patients with chest pain in the emergency department using electron beam tomography: a follow-up study. J Am Coll Cardiol. 2001;38(1):105–10. 5. Laudon DA, Vukov LF, Breen JF, Rumberger JA, Wollan PC, Sheedy PF. Use of electron-beam computed tomography in the evaluation of chest pain patients in the emergency department. Ann Emerg Med. 1999;33(1):15–21. 6. McLaughlin VV, Balogh T, Rich S. Utility of electron beam computed tomography to stratify patients presenting to the emergency room with chest pain. Am J Cardiol. 1999;84(3): 327–8. 7. Hulten E, Bittencourt MS, Ghoshhajra B, O’Leary D, Christman MP, Blaha MJ, et al. Incremental prognostic value of coronary artery calcium score versus CT angiography among symptomatic patients without known coronary artery disease. Atherosclerosis. 2014;233(1):190–5. 8. Villines TC, Hulten EA, Shaw LJ, Goyal M, Dunning A, Achenbach S, et al. Prevalence and severity of coronary artery disease and adverse events among symptomatic patients with coronary artery calcification scores of zero undergoing coronary computed tomography angiography: results from the CONFIRM (Coronary CT Angiography Evaluation for Clinical Outcomes: An International Multicenter) registry. J Am Coll Cardiol. 2011;58(24):2533–40. 9. Hollander JE, Chang AM, Shofer FS, Collin MJ, Walsh KM, McCusker CM, et al. One-year outcomes following coronary computerized tomographic angiography for evaluation of emergency department patients with potential acute coronary syndrome. Acad Emerg Med. 2009;16(8):693–8. 10. Schlett CL, Banerji D, Siegel E, Bamberg F, Lehman SJ, Ferencik M, et al. Prognostic value of CT angiography for major adverse cardiac events in patients with acute chest pain from the emergency department: 2-year outcomes of the ROMICAT trial. JACC Cardiovasc Imaging. 2011;4(5):481–91. 11. •• Hulten E, Pickett C, Bittencourt MS, Villines TC, Petrillo S, Di Carli MF, et al. Outcomes after coronary computed tomography angiography in the emergency department. J Am Coll Cardiol. 2013;61(8):880–92. First primary metaanalysis of the RCT no deaths and no difference in the incidence of myocardial infarction, postdischarge ED visits, or repeat hospitalization compared with patients who underwent usual care. However, there was an increased incidence of invasive coronary angiography and coronary revascularization among patients evaluated by CTA, of uncertain clinical significance.
Curr Radiol Rep (2015) 3:38 12. Budoff MJ, Dowe D, Jollis JG, Gitter M, Sutherland J, Halamert E, et al. Diagnostic performance of 64-multidetector row coronary computed tomographic angiography for evaluation of coronary artery stenosis in individuals without known coronary artery disease: results from the prospective multicenter ACCURACY (Assessment by Coronary Computed Tomographic Angiography of Individuals Undergoing Invasive Coronary Angiography) trial. J Am Coll Cardiol. 2008;52(21):1724–32. 13. Meijboom WB, Meijs MFL, Schuijf JD, Cramer MJ, Mollet NR, van Mieghem CAG, et al. Diagnostic accuracy of 64-slice computed tomography coronary angiography: a prospective, multicenter, multivendor study. J Am Coll Cardiol. 2008;52(25):2135–44. 14. Miller JM, Rochitte CE, Dewey M, Arbab-Zadeh A, Niinuma H, Gottlieb I, et al. Diagnostic performance of coronary angiography by 64-row CT. N Engl J Med. 2008;359(22):2324–36. 15. Hetterich H, Nikolaou K, Reiser MF, Bamberg F. The big picture: evidence base and current trials in cardiac CT. Curr Radiol Rep. 2013;1(4):246–54. 16. Antman EM, Cohen M, Bernink PJ, McCabe CH, Horacek T, Papuchis G, et al. The TIMI risk score for unstable angina/nonST elevation MI: a method for prognostication and therapeutic decision making. JAMA. 2000;284(7):835–42. 17. • Goldstein JA, Chinnaiyan KM, Abidov A, Achenbach S, Berman DS, Hayes SW, et al. The CT-STAT (Coronary Computed Tomographic Angiography for Systematic Triage of Acute Chest Pain Patients to Treatment) trial. J Am Coll Cardiol. 2011;58(14):1414–22. CT_STAT trial was the first multicenter RCT demonstrated no MACE in patients randomized to CT vs SOC. 18. Cury RC, Budoff M, Taylor AJ. Coronary CT angiography versus standard of care for assessment of chest pain in the emergency department. J Cardiovasc Comput Tomogr. 2013;7(2):79–82. 19. •• Litt HI, Gatsonis C, Snyder B, Singh H, Miller CD, Entrikin DW, et al. CT angiography for safe discharge of patients with possible acute coronary syndromes. N Engl J Med. 2012;366(15):1393–403. The ACRIN trial was the second multicenter trial evaluating CTA in the ED. In addition to clinical parameters, the study also looked at higher rate of discharge from the ED (49.6% vs 22.7%), a shorter length of stay (median, 18.0 vs 24.8 hours; P \ .001). 20. • Taylor AJ, Cerqueira M, Hodgson JM, Mark D, Min J, O’Gara P, 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 Cardiovasc Comput Tomogr. 2010;4(6):407.e1–33. Review of common clinical scenarios where cardiac computed tomography (CCT) is frequently considered. The indications for this review were drawn from common applications or anticipated uses, as well as from current clinical practice guidelines. 21. Shapiro MD, Dodd JD, Kalva S, Wittram C, Hsu J, Nasir K, et al. A comprehensive electrocardiogram-gated 64-slice multidetector computed tomography imaging protocol to visualize the coronary arteries, thoracic aorta, and pulmonary vasculature in a single breath hold. J Comput Assist Tomogr. 2009;33(2):225–32. 22. Bischoff B, Hein F, Meyer T, Hadamitzky M, Martinoff S, Scho¨mig A, et al. Impact of a reduced tube voltage on CT angiography and radiation dose: results of the PROTECTION I study. JACC Cardiovasc Imaging. 2009;2(8):940–6.
Page 7 of 8 38 23. Hausleiter J, Meyer T, Hermann F, Hadamitzky M, Krebs M, Gerber TC, et al. Estimated radiation dose associated with cardiac CT angiography. JAMA. 2009;301(5):500–7. 24. • Achenbach S, Marwan M, Ropers D, Schepis T, Pflederer T, Anders K, et al. Coronary computed tomography angiography with a consistent dose below 1 mSv using prospectively electrocardiogram-triggered high-pitch spiral acquisition. Eur Heart J. 2010;31(3):340–6. Demonstrates that prospectively ECG-triggered coronary CTA with high pitch provides excellent image quality at a consistent dose below 1.0 mSv. 25. Husmann L, Herzog BA, Gaemperli O, Tatsugami F, Burkhard N, Valenta I, et al. Diagnostic accuracy of computed tomography coronary angiography and evaluation of stress-only single-photon emission computed tomography/computed tomography hybrid imaging: comparison of prospective electrocardiogram-triggering vs. retrospective gating. Eur Heart J. 2009;30(5):600–7. 26. Halpern EJ. Triple-rule-out CT angiography for evaluation of acute chest pain and possible acute coronary syndrome. Radiology. 2009;252(2):332–45. 27. Kligerman SJ, White CS. Image quality and feasibility of an ultralow-dose high-pitch helical triple-rule-out computed tomography angiography acquired in the caudocranial direction. J Thorac Imaging. 2014;29(1):50–9. 28. •• Leipsic J, Labounty TM, Heilbron B, Min JK, Mancini GBJ, Lin FY, et al. Estimated radiation dose reduction using adaptive statistical iterative reconstruction in coronary CT angiography: the ERASIR study. AJR Am J Roentgenol. 2010;195(3):655–60. 331 studies with FBP was compared with a subsequent group of 243 studies with IR. The coronary CTA reconstructed with IR had a 31%-lower median tube current and a 44%-lower median effective dose than those reconstructed with FBP, with no difference in image noise. 29. Shuman WP, Branch KR, May JM, Mitsumori LM, Strote JN, Warren BH, et al. Whole-chest 64-MDCT of emergency department patients with nonspecific chest pain: Radiation dose and coronary artery image quality with prospective ECG triggering versus retrospective ECG gating. AJR Am J Roentgenol. 2009;192(6):1662–7. 30. Stehli J, Fuchs TA, Bull S, Clerc OF, Possner M, Buechel RR, et al. Accuracy of coronary CT angiography using a submillisievert fraction of radiation exposure: comparison with invasive coronary angiography. J Am Coll Cardiol. 2014;64(8):772–80. 31. • Hoffmann U, Truong QA, Schoenfeld DA, Chou ET, Woodard PK, Nagurney JT, et al. Coronary CT angiography versus standard evaluation in acute chest pain. N Engl J Med. 2012;367(4):299–308. The ROMICAT-II trial has been the largest multicenter trial so far demonstrating no differences in MACE between the CT and SOC groups. There was also a higher rate of discharge and lower median length of stay in the CCTA group compared with SOC. 32. Khare RK, Courtney DM, Powell ES, Venkatesh AK, Lee TA. Sixty-four-slice computed tomography of the coronary arteries: cost-effectiveness analysis of patients presenting to the emergency department with low-risk chest pain. Acad Emerg Med. 2008;15(7):623–32. 33. Ladapo JA, Hoffmann U, Bamberg F, Nagurney JT, Cutler DM, Weinstein MC, et al. Cost-effectiveness of coronary MDCT in the triage of patients with acute chest pain. AJR Am J Roentgenol. 2008;191(2):455–63. 34. Maurovich-Horvat P, Hoffmann U, Vorpahl M, Nakano M, Virmani R, Alkadhi H. The napkin-ring sign: CT signature of high-risk coronary plaques? JACC Cardiovasc Imaging. 2010;3(4):440–4. 35. Motoyama S, Sarai M, Harigaya H, Anno H, Inoue K, Hara T, et al. Computed tomographic angiography characteristics of
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Page 8 of 8 atherosclerotic plaques subsequently resulting in acute coronary syndrome. J Am Coll Cardiol. 2009;54(1):49–57. Madder RD, Raff GL, Hickman L, Foster NJ, McMurray MD, Carlyle LM, et al. Comparative diagnostic yield and 3-month outcomes of ‘‘triple rule-out’’ and standard protocol coronary CT angiography in the evaluation of acute chest pain. J Cardiovasc Comput Tomogr. 2011;5(3):165–71. Kern MJ, Samady H. Current concepts of integrated coronary physiology in the catheterization laboratory. J Am Coll Cardiol. 2010;55(3):173–85. Pijls NH, De Bruyne B, Peels K, Van Der Voort PH, Bonnier HJ, Bartunek J, Koolen JJ, et al. Measurement of fractional flow reserve to assess the functional severity of coronary-artery stenoses. N Engl J Med. 1996;334(26):1703–8. Branch KR, Busey J, Mitsumori LM, Strote J, Caldwell JH, Busch JH, et al. Diagnostic performance of resting CT
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Curr Radiol Rep (2015) 3:38 myocardial perfusion in patients with possible acute coronary syndrome. AJR Am J Roentgenol. 2013;200(5):W450–7. 40. •• Rochitte CE, George RT, Chen MY, Arbab-Zadeh A, Dewey M, Miller JM, et al. Computed tomography angiography and perfusion to assess coronary artery stenosis causing perfusion defects by single photon emission computed tomography: the CORE320 study. Eur Heart J. 2014;35(17):1120–30. 381-patient, 16-center trial, which showed that stress CT myocardial perfusion analysis (CTP) with 320-detector-row coronary CT angiography (CCTA) significantly improves the diagnostic power of rest CT angiography (CTA) alone; and is also better than SPECT myocardial perfusion imaging (MPI) for diagnosing coronary artery disease (CAD).
