White et al.
2003 and July 2004 were approached for recruit- TABLE 1: Demographics of 20-gauge angiocatheter into an antecubital vein at
ment in this prospective study. Acute chest pain in 69 Patients with Chest Pain 3–4 mL/sec. Automated bolus timing was per-
the University of Maryland emergency department Demographic Variable No. % formed using a threshold value of 150 H and a re-
is typically classified on a scale of 1 to 5 on the ba- Patient age (yr) gion of interest placed over the ascending aorta. Af-
sis of the initial clinical impression. These are clin- ter additional IRB approval was obtained, a β-
ical categories based on the patient’s chief com- blocker (Lopressor [metoprolol, Novartis], 5 mg
plaint, symptoms and signs, risk factors, and ECG. IV) was used to control heart rates greater than 70
Category 1 is an acute myocardial infarction. Cate- Patient sex beats per minute. Of the final 32 patients, 10 re-
gory 2 is considered definite angina with uncer- Male 35 51 ceived β-blockers.
tainty regarding acute myocardial infarction. Cate- Female 34 49 The average scanning time was 30 sec with an
gories 3, 4, and 5 are probable angina, probably not additional 3–4 min for preprocedure placement and
Chest pain evaluation category
angina, and not angina, respectively. Patients in adjustment of the ECG leads. A large field of view
2 17 25
whom there is less concern for angina but suspicion (350–400 mm) was used to encompass the entire
of clinically significant noncoronary chest pain 3 32 46 chest at 75% of the R-R interval. The raw data were
(e.g., pulmonary embolism) are usually graded as 4 18 26 used to reconstruct axial images as well as coronal
category 3 or 4 rather than category 5, conferring a None assigned 2 3 and sagittal maximum-intensity-projection refor-
nonanginal component to the classification system. Smoker (current or former) 48 70 mations. Axial images were also subsequently re-
These are not final diagnoses but rather simple, constructed in a smaller field of view (250 mm) tar-
Nonsmoker 21 30
practical, and functional categories along a contin- geted to the heart. These reconstructions were
uum adopted broadly by emergency physicians and CHD risk factors obtained at 10% intervals for a total of 10 phases.
advocated by the Society of Chest Pain Centers . 0 6
Clinically stable patients with chest pain classi- 1–2 25 Image Interpretation
fied from 2 to 4 were eligible for inclusion based on 3–4 26 An initial assessment was made of noncardiac
the assessment of the emergency department phy- disease and for the contrast-enhanced presence of
sician and other inclusion and exclusion criteria. In- coronary artery calcification using the large field-
Body mass index
clusion criteria included age greater than 18 years of-view images (ECG-gated 75% R-R interval).
and the ability to understand and sign a consent < 25 15 Specific noncardiac entities that were evaluated in-
form. Exclusion criteria were clinical instability 25–30 13 cluded, but were not limited to, aortic dissection,
(such as arrhythmia, congestive heart failure, and > 30 18 pulmonary embolism, pneumonia, pneumothorax,
hypotension), compromised renal function, aller- Not obtained 23 pericardial effusion, and rib fracture. A qualitative
gies to contrast material, and pregnancy. Category assessment of the presence and extent of coronary
Note—CHD = coronary heart disease.
1 patients were excluded because of clinical insta- artery calcifications was made. No quantitative
bility. Category 5 patients were deemed unlikely to software was used because all scans were obtained
have a significant cause of chest pain and were also was given by each patient. All Health Insurance after the administration of IV contrast material.
excluded. The emergency department physician Portability and Accountability Act procedures Coronary artery calcification was characterized as
was asked in each case before the study whether CT were followed. As part of the study protocol, all pa- none, mild, moderate, or severe. All of this infor-
would have been performed for the conventional tients enrolled in the study received a consultation mation was immediately communicated to the clin-
workup. The CT study was done early in the clini- with a cardiologist. ical team in the emergency department using a pre-
cal evaluation of the patient in the interval immedi- liminary report form (Fig. 1A). This abbreviated
ately after the ECG was done and blood samples Image Acquisition initial evaluation was necessitated by the time re-
drawn and before a decision was made as to further CT scans were acquired on each patient using a quired to reconstruct the 10 cardiac phases consist-
care or studies for the patient and before results of 16-MDCT scanner (MX8000IDT, Philips Medical ing of 2,500–3,500 images, which ranged from 15
cardiac enzymes were available. Patient demo- Systems). The CT scanner is located adjacent to the min if all images were reconstructed immediately
graphics are summarized in Table 1. emergency suite, and thus patients could be moni- to several hours, depending on other duties of the
Seventy-eight patients with chest pain were en- tored as necessary by emergency department per- technologists and the clinical demands made on the
rolled. Nine patients were excluded before com- sonnel while undergoing CT. For each patient, ret- CT scanner.
pleting the protocol. In four patients, the CT was rospective ECG-gated images were obtained All imaging data were processed by a fellow re-
performed but the raw projection data were erased through the entire chest during a single breath-hold ceiving training in thoracic radiology using a dedi-
from the scanner hard drive before multiple phases beginning at the inferior margin of the heart and ex- cated workstation (MxView, Philips Medical Sys-
of the cardiac cycle could be reconstructed. In three tending to the top of the lung apices. Patients were tems). Postprocessing consisted of the calculation of
patients, no CT was performed because the patients advised to exhale slowly if they could not maintain ejection fraction and the generation of curved planar
were undergoing evaluation elsewhere and could breath-holding throughout the scanning. The scan- reconstructions of each of the main coronary arter-
not be scheduled for CT. The other two patients left ning protocol included collimation of 0.75 × 16 mm ies. The 10 cardiac phases were loaded into a cine
the emergency department against medical advice with reconstructed axial image thickness of 1 mm. loop, and wall motion was assessed qualitatively for
before CT scanning. Ultimately, 69 patients partic- Scanning technique was 140 kVp and 350–500 areas of hypo- or akinesis and to determine the end-
ipated in the chest pain protocol. mAs. A pitch of 0.2–0.3 was used with a scanner diastolic and end-systolic phases for analysis of the
The study protocol was approved by our institu- rotation time of 0.42 sec. Iodinated contrast mate- ejection fraction. The endocardial margins on these
tional review board (IRB) and informed consent rial, 120–150 mL, was injected through an 18- to phases were drawn manually on contiguous short-
534 AJR:185, August 2005
Emergency Department Evaluation of Chest Pain
Fig. 1—Radiology report forms.
A and B, Initial (A) and final (B) case report forms. Final form also included a coronary artery scoring sheet (not shown).
axis images. Papillary muscles were excluded from cardiology consultant. A final CT assessment of the who did not receive further testing, the diagnosis
contouring. Automated software summated the sur- cause of the chest pain was recorded on a case re- provided at the time of discharge from the emer-
face areas of these images to calculate the ejection port form (Fig. 1B). gency department by the emergency department
fraction according to the formula: physician was deemed definitive. For patients who
Clinical Follow-Up and Assessment had coronary angiography, stress echocardio-
ejection fraction = (end-diastolic volume – Emergency department data and all available graphy, or radionuclide stress testing, the results of
end-systolic volume) / end-diastolic volume. medical records were reviewed for each patient be- these tests were used to arrive at a final judgment.
tween 1 and 2 months after the emergency depart- Positive coronary angiography was defined as
Short- and long-axis images were assessed for per- ment visit. Data were collected as to whether the showing a stenosis greater than 50% in a major ves-
fusion defects on each phase and were defined as patient left against medical advice from the emer- sel. For clinically significant diagnoses for which
areas of decreased perfusion that could be visual- gency department and whether the patient required CT is considered a standard reference technique
ized in two projections. either hospitalization or a subsequent emergency (e.g., pulmonary embolism, aortic dissection), the
Construction of curved planar reconstructions of department visit. In addition to the CT, information CT findings were regarded as definitive. Using
the coronary arteries was based on the optimal car- on other relevant diagnostic tests was recorded, in- these guidelines based on the best available clinical
diac phase, defined as that with the least amount of cluding coronary angiography, stress echocardio- and testing information, a final diagnosis for the
motion. The axial and postprocessed images were graphy, or radionuclide stress testing obtained emergency department visit was determined. Fi-
assessed for the presence of stenosis, which was within 1 month of presentation to the emergency nally, results of invasive coronary angiography,
quantified subjectively as being greater (signifi- department. stress echocardiography, and radionuclide stress
cant) or less than 50% (nonsignificant). All imag- A consensus group consisting of one emergency testing were correlated with their respective find-
ing observations were agreed on by consensus of department physician, one cardiologist, and one ra- ings on CT angiography.
the two radiologists. Because the final assessment diologist was convened to determine a final diagno-
was typically completed after patient triage, coro- sis. The consensus group used the following guide- Statistical Analysis
nary stenoses or other significant findings identi- lines to adjudicate each case: For patients who were Sensitivity, specificity, positive predictive
fied after postprocessing were communicated to the discharged from the emergency department and value, and negative predictive value were calcu-
AJR:185, August 2005 535
White et al.
lated for the emergency department CT using the fi- radionuclide testing in 15 (22%), coronary oral diphenhydramine, with prompt resolu-
nal clinical diagnosis as the reference standard. angiography in 11(16%), stress echocardio- tion of symptoms. A 54-year-old man devel-
Separate values were calculated for the diagnosis of graphy in six (9%), and CT alone in three oped renal insufficiency after the contrast-en-
cardiac chest pain only and for the full assessment (4%). The diagnoses made on CT alone were hanced CT and required 2 days of additional
of cardiac and noncardiac diagnoses. For differ- those with noncardiac causes, for which CT is hospitalization. He was discharged with base-
ences between ejection fractions as calculated on a standard reference technique. line renal function.
MDCT and radionuclide testing, an unpaired t test The sensitivity of CT as compared with the
was used. A p value of less than 0.05 was consid- final diagnosis for coronary artery disease Discussion
ered to indicate statistical significance. was 83%. Specificity, negative predictive Substantial advances have occurred in pa-
value, and positive predictive value were tient evaluation and triage over the past de-
Results 96%, 96%, and 83%, respectively. Overall, cade, but the assessment of chest pain in the
Overall Clinical Assessment the sensitivity of cardiac and noncardiac con- emergency department remains a significant
The 69 patients who completed the chest ditions (including CT-based diagnoses) was challenge. Although a cardiac or noncardiac
pain protocol included 35 men (51%) and 34 87%. Specificity, negative predictive value, diagnosis may be immediately apparent, ini-
women (49%) with a mean age of 51 years and positive predictive value were 96%, 96%, tial clinical evaluation is often equivocal, re-
(range, 33–81 years). Forty-five patients and 87%, respectively. sulting in a high proportion of hospital admis-
(65%) would not otherwise have undergone sions . Nevertheless, it is estimated that
CT, according to the judgment of the emer- Coronary Artery Calcification 4–8% of patients are inappropriately dis-
gency physician caring for the patient. Seven- Qualitative analysis of the extent of coro- charged from the emergency department and
teen patients (25%) presented with chest pain nary artery calcification on the contrast-en- ultimately prove to have a myocardial infarc-
that was classified as category 2, 32 (46%) hanced study revealed no calcification in 42 tion, the most important cause of acute chest
with category 3, and 18 (26%) with category patients. Mild, moderate, or severe amounts pain [7, 8].
4. In two patients (3%), no category was as- of calcification were present in 19, four, and In the emergency department, the diagno-
signed by the emergency physician. Twenty- four patients, respectively. Of the 10 patients sis of acute cardiac ischemia, which includes
nine patients (42%) required hospital admis- with significant coronary artery disease found acute myocardial infarction and unstable an-
sion for further evaluation, including 13 on CT, coronary artery calcification was gina, remains primarily clinical, and is guided
(76%) of those with category 2 pain, 11 graded qualitatively as mild in one, moderate by history, risk factors, and ECG results. This
(32%) with category 3 pain, and three (17%) in six, and severe in three. Of the two patients diagnostic pathway is known to lack sensitiv-
with category 4 pain. Both patients for whom with negative CT findings who proved to ity [9, 10]. Serum markers of myocardial in-
no category was assigned were also admitted. have coronary artery disease, one had no vis- jury (CK-MB [creatininekinase myoglobin]
One patient was ruled in for an acute myocar- ible coronary artery calcification and the sec- troponin, and myoglobin) also are a critical
dial infarction and a second was diagnosed ond had mild coronary artery calcification. part of chest pain assessment but typically do
with acute coronary syndrome. not show elevations until more than 6 hr after
Fifty-two (75%) of the 69 patients had no Functional Assessment the onset of the chest pain . Thus, they
significant CT findings and a final diagnosis Twenty-one patients underwent stress nu- may not be useful in the hyperacute setting
of clinically insignificant chest pain (Fig. 2). clear medicine testing with calculation of when the administration of thrombolytics
Thirteen patients (19%) had significant CT ejection fraction within 1 week of the MDCT. might lead to maximal preservation of myo-
findings concordant with the final diagnosis MDCT yielded a significantly higher ejection cardial tissue. Moreover, these markers do
(cardiac, 10; noncardiac, 3). Each of the 10 fraction (mean, 63%; range, 47–82%) than not allow rapid exclusion of myocardial is-
patients with cardiac disease and a positive the radionuclide study (mean, 52%; range, chemia, which would permit early discharge
CT diagnosis was deemed to have a diagnosis 36–63%) in these patients (p < 0.01). Twelve from the emergency department.
of angina due to coronary artery disease patients had a difference of 10% or less be- Other imaging-based diagnostic strategies
(Fig. 3). The three noncardiac diagnoses were tween the radionuclide stress and MDCT have been attempted to assess cardiac causes
pericarditis with a moderately large pericar- ejection fraction, five and four patients had of chest pain. Echocardiography with the
dial effusion, subtle pneumonia, and pulmo- discrepancies of 11–20% and 21–30%, re- patient at rest and after stress can show wall
nary embolism (Figs. 4 and 5). In two patients spectively. One patient showed a focal perfu- motion abnormalities due to ischemia and can
(3%), CT failed to suggest a clinically signif- sion defect at the cardiac apex on CT (Fig. 7). assess valvular, pulmonary artery, and peri-
icant diagnosis. Both of those were clinically A wall motion abnormality was identified in cardial disease [12–14]. However, the tech-
significant coronary artery stenoses identified a similar location on stress echocardiography. nique is operator dependent and requires
on angiography in the left anterior descending considerable experience. Moreover, poor
and first diagonal branches, respectively. In Complications acoustic windows may limit the study .
both patients, image quality was adversely af- Non-life-threatening complications that Nuclear scintigraphy using thallium or
fected by motion (Fig. 6). In two additional were ascribed to the trial protocol occurred in technetium-99m sestamibi may detect abnor-
instances (3%), CT overdiagnosed a coronary two patients. One 40-year-old woman devel- malities of myocardial perfusion, but this may
stenosis. Both incorrectly identified lesions oped urticaria shortly after discharge from the reflect remote infarction. These techniques
were in the mid left anterior descending ar- emergency department that was presumably have a high sensitivity and moderate specific-
tery. The decision on final diagnosis was caused by IV contrast material. She returned ity . An important additional limitation is
based on clinical data in 34 patients (49%), to the emergency department and was given the need to transport the patient to a gamma
536 AJR:185, August 2005
Emergency Department Evaluation of Chest Pain
Fig. 2—48-year-old man who presented to emergency department with chest pain and normal coronary arteries by CT angiography.
A and B, Curved planar reformations from MDCT show right coronary artery (A) and left anterior descending artery (B).
Fig. 3—52-year-old man who presented to emergency department with chest pain.
A, Curved planar reformation from CT angiogram from MDCT shows area of proximal left anterior descending artery (LAD) stenosis (arrow).
B, Coronary angiogram confirms LAD stenosis (arrow).
AJR:185, August 2005 537
White et al.
Fig. 4—56-year-old woman who presented to emergency department with chest Fig. 5—60-year-old man who presented to emergency department with chest pain.
pain. Left lower lobe pneumonia was found on MDCT. No coronary stenosis was Axial MDCT scan shows pulmonary embolism in right middle lobe pulmonary artery
camera, which is often in a remote location low prevalence indicates the potential impact clinically significant cardiac and noncardiac
. MRI is often impractical because of the of the MDCT protocol, if completed expedi- causes of chest pain in most cases.
need for specialized equipment that may not tiously, to rapidly triage patients, particularly Other aspects of the MDCT cardiac evalu-
be available in the emergency department and those with a negative study. ation were less valuable. The assessment of
a substantial prevalence of claustrophobia In our study, several patients had chest pain coronary artery perfusion after enhancement
. Each of these imaging techniques is also caused by coronary artery disease, and was quite subjective. No quantitative thresh-
limited in its capability to detect extracardiac MDCT showed coronary artery calcification old has been established to define such a de-
causes of chest pain. or areas of coronary stenosis in most of these fect. When a defect was conclusively present
CT, in particular electron beam CT, has patients. However, in two patients, an area of in the judgment of the two observers, its chro-
been used to risk-stratify patients with acute significant coronary artery narrowing on cor- nicity could not be determined. Similar con-
chest pain by revealing coronary calcium . onary arteriography was not detected on CT. siderations apply to the evaluation of wall
The absence of calcification is associated with In part, this deficiency may have been due to motion abnormalities. Ejection fraction was
a very low likelihood of acute cardiac is- the way the CT scan was acquired. Our proto- depressed in a minority of patients, with a rea-
chemia. The latest generation of MDCT scan- col entailed a global evaluation of chest pain sonable correlation with results from nuclear
ners features ECG-gating, submillimeter spa- and thus represented a necessary compromise medicine testing when available.
tial resolution, and relatively good temporal between evaluating the coronary arteries and Although the number of clinically signifi-
resolution that permit adequate assessment of the remainder of the chest. We used a larger cant abnormalities was low in this pilot study
coronary artery anatomy [18, 19]. focal spot and larger field of view than are of an acute chest pain imaging protocol,
Our pilot study shows that MDCT is a fea- typical for a dedicated coronary artery evalu- MDCT showed the potential to be a valuable
sible approach to provide a comprehensive ation, and we subsequently reconstructed a method for excluding significant cardiogenic
chest pain evaluation in the emergency depart- smaller field of view centered around the causes of chest pain, including coronary ar-
ment. We selected patients with chest pain lev- heart. In addition, scanning was initiated at tery stenoses greater than 50%, as evidenced
els of 2 to 4 who were deemed to be clinically the bottom of the heart and extended cephalad by a high negative predictive value. Com-
stable. It is this group of patients without defi- for an uninterrupted acquisition through the pletely normal or not significantly abnormal
nite evidence of myocardial infarction in entire chest, in contrast to the typical coro- MDCT findings was the most common result
whom MDCT may have its greatest impact. nary artery protocol that progresses inferiorly in our series and was confirmed in most cases
None of our patients ultimately proved to have from a level just above the coronary arteries. by the final diagnosis. In addition, MDCT
myocardial infarction or unstable angina. These modifications undoubtedly led to some was valuable for suggesting noncardiac diag-
Presumably this is because of our restrictive in- degradation of coronary artery images. More- noses such as pneumonia and pulmonary em-
clusion criteria and the low prevalence of my- over, β-blockers were not used for the initial bolism. In this respect, MDCT has an advan-
ocardial infarction (~ 5%) that has been docu- portion of the study. Despite the limitations of tage over other imaging techniques, such as
mented in our emergency department. This the technique, MDCT was able to diagnose perfusion radionuclide scintigraphy and
538 AJR:185, August 2005
Emergency Department Evaluation of Chest Pain
Fig. 6—60-year-old woman who presented to emergency department with chest
A, Curved planar reformation from CT angiogram on MDCT was interpreted as neg-
ative. Arrow points to narrowed branch that was not identified prospectively.
B, Coronary angiogram shows a 50–60% stenosis (arrow) of diagonal branch.
C, Repeat curved planar reformation produced after discrepancy was reported sug-
gests presence of stenotic area (arrow) in retrospect.
Fig. 7—56-year-old man who presented to emergency department with history of
myocardial infarction (MI) and chest pain. MDCT scan shows endocardial apical
perfusion defect (arrows). Patient was asymptomatic at time of scanning with neg-
ative acute MI evaluation, and defect was deemed to be chronic.
AJR:185, August 2005 539
White et al.
echocardiography, that are sometimes used in and noncardiac causes of acute chest pain in emergency room. Am J Cardiol 1987; 60:219–224
the emergency department setting. the emergency department with MDCT is lo- 8. McCarthy BD, Beshansky JR, D’Agostino RB,
Several limitations of this study must be gistically feasible and may provide clini- Selker HP. Missed diagnoses of acute myocardial
emphasized. First, because this was a feasibil- cally meaningful data. The greatest potential infarction in the emergency department: results
ity study, the number of enrolled patients was impact appears to be in the exclusion of sig- from a multicenter study. Ann Emerg Med 1993;
small. Second, as described earlier, the goal nificant cardiac disease to supplement as- 22:579–582
of providing a complete thoracic assessment sessment of established indications in life- 9. Brush JE Jr, Brand DA, Acampora D, Chalmer B,
that included pulmonary embolism and aortic threatening noncardiac disease such as pul- Wackers FJ. Use of the initial electrocardiogram
dissection necessitated a compromise proto- monary embolism and aortic dissection. to predict in-hospital complications of acute my-
col that was not optimized to the coronary However, in patients with suspected coro- ocardial infarction. N Engl J Med 1985;
arteries. Another technology-related short- nary disease based on CT, further study is 312:1137–1141
coming was that the time required for post- needed to more clearly elucidate its sensitiv- 10. Lee TH, Rouan GW, Weisberg MC, et al. Sensitiv-
processing necessitated an initial general ity for clinically significant coronary artery ity of routine clinical criteria for diagnosing myo-
evaluation followed by a more detailed car- stenoses. Moreover, routine implementation cardial infarction within 24 hours of hospitalization.
diac evaluation, often separated by several of this technique will require further techno- Ann Intern Med 1987; 106:181–186
hours or more. Thus, a real-time coronary ar- logic advances, such as more rapid scanning 11. Lau J, Ioannidis JP, Balk EM, et al. Diagnosing
tery assessment proved difficult or impossi- and reconstruction, and greater ease of im- acute cardiac ischemia in the emergency depart-
ble. With the advent of the latest generation of age postprocessing. The potential exists that ment: a systematic review of the accuracy and clin-
64-MDCT scanners, these limitations may be these advances will lead to greater reliability ical effect of current technologies. Ann Emerg Med
mitigated as a result of faster image acquisi- of delineation of coronary artery anatomy 2001; 37:453–460
tion, better spatial and temporal resolution, and cardiac function, permitting contempo- 12. Bholasingh R, Cornel JH, Kamp O, et al. Prognostic
and more rapid postprocessing. raneous clinical feedback of the entire value of predischarge dobutamine stress echocar-
A fourth limitation was the lack of a stan- MDCT examination to the emergency diography in chest pain patients with a negative car-
dard end point to assess final diagnosis. As department team, thereby facilitating a more diac troponin T. J Am Coll Cardiol 2003;
noted, the patients had variable clinical eval- expeditious triage of the patient with 41:596–602
uations and some had no documented follow- chest pain. 13. Soman P, Bokor D, Lahiri A. Why cardiac magnetic
up at our institution after their index emer- resonance imaging will not make it. J Comput Assist
gency department visit. In particular, only a Tomogr 1999; 23[suppl 1]:S143–S149
minority of patients ultimately underwent References 14. Gibler WB, Runyon JP, Levy RC, et al. A rapid di-
coronary angiography, the anatomic standard 1. Lawler LP, Fishman EK. Multidetector row com- agnostic and treatment center for patients with chest
of reference. Thus, determination of a final puted tomography of the aorta and peripheral arter- pain in the emergency department. Ann Emerg Med
diagnosis was necessarily subjective in many ies. Cardiol Clin 2003; 21:607–629 1995; 25:1–8
instances. This shortcoming is common in 2. Schoepf UJ, Costello P. Multidetector-row CT im- 15. Kontos MC, Tatum JL. Imaging in the evaluation of
studies involving emergency department pa- aging of pulmonary embolism. Semin Roentgenol the patient with suspected acute coronary syn-
tients . Finally, the design of the study did 2003; 38:106–114 drome. Semin Nucl Med 2003; 33:246–258
not permit assessment of high-risk or less sta- 3. Ropers D, Baum U, Pohle K, et al. Detection of cor- 16. Kwong RY, Schussheim AE, Rekhraj S, et al. De-
ble patients, thereby limiting the number of onary artery stenoses with thin-slice multi-detector tecting acute coronary syndrome in the emergency
subjects with clinically significant coronary row spiral computed tomography and multiplanar department with cardiac magnetic resonance imag-
artery stenoses. Further studies of this tech- reconstruction. Circulation 2003; 107:664–666 ing. Circulation 2003; 107:531–537
nique will need to assess its performance 4. Achenbach S, Ropers D, Pohle K, et al. Clinical re- 17. Georgiou D, Budoff MJ, Kaufer E, Kennedy JM, Lu
when evaluating patients with a higher likeli- sults of minimally invasive coronary angiography B, Brundage BH. Screening patients with chest pain
hood of coronary artery disease. using computed tomography. Cardiol Clin 2003; in the emergency department using electron beam
An additional consideration is that CT may 21:549–559 tomography: a follow-up study. J Am Coll Cardiol
not be the best technique to diagnose certain 5. Tatum JL, Jesse RL, Kontos MC, et al. Comprehen- 2001; 38:105–110
causes of chest pain. For instance, muscu- sive strategy for the evaluation and triage of the 18. Schoenhagen P, Halliburton SS, Stillman AE, et al.
loskeletal chest pain is often best evaluated on chest pain patient. Ann Emerg Med 1997; Noninvasive imaging of coronary arteries: current
physical examination, gastrointestinal reflux 29:116–125 and future role of multi-detector row CT. Radiology
disease may be assessed with manometric 6. Pozen MW, D’Agostino RB, Selker HP, Sytkowski 2004; 232:7–17
testing, and pneumonia is often better seen on PA, Hood WB Jr. Predictive instrument to improve 19. Schoepf UJ, Becker CR, Ohnesorge BM, Yucel EK.
chest radiography. Thus, although CT has po- coronary-care-unit admission practices in acute is- CT of coronary artery disease. Radiology 2004;
tential value in the diagnosis of many life- chemic heart disease: a prospective multicenter 232:18–37
threatening causes of chest pain, not every clinical trial. N Engl J Med 1984; 310:1273–1278 20. Ioannidis JP, Salem D, Chew PW, Lau J. Accuracy
cause of chest pain can be diagnosed. 7. Lee TH, Rouan GW, Weisberg MC, et al. Clinical of imaging technologies in the diagnosis of acute
In summary, our pilot study suggests that characteristics and natural history of patients with cardiac ischemia in the emergency department: a
a comprehensive evaluation of many cardiac acute myocardial infarction sent home from the meta-analysis. Ann Emerg Med 2001; 37:471–477
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