ACR Appropriateness Criteria®
Clinical Condition: Acute Chest Pain -- Low Probability of Coronary Artery Disease
| Radiologic Procedure |
Rating |
Comments |
RRL* |
| X-ray chest |
9 |
|
Min |
| NUC myocardial perfusion scan |
8 |
If a cardiac etiology is suspected. |
High |
| CTA coronary arteries |
7 |
If a cardiac etiology is suspected. |
High |
| MRI heart with stress with or without contrast |
7 |
If local expertise is available. See comments regarding contrast in the text below under "Anticipated Exceptions." |
None |
| CTA chest (noncoronary) |
6 |
Useful in ruling out other causes of chest pain such as aortic dissection, pulmonary embolism, pneumothorax, pneumonia. |
Med |
| US echocardiography transthoracic |
6 |
If a cardiac etiology is suspected. |
None |
| US echocardiography transesophageal |
6 |
If a cardiac etiology is suspected. To exclude aortic dissection if MDCT and/or MRI are nondiagnostic. |
None |
| MRA chest (noncoronary) |
5 |
Alternative to MDCT if aortic dissection is suspected. See comments regarding contrast in the text below under "Anticipated Exceptions." |
None |
| NUC Tc-99m V/Q scan lung |
5 |
If contrast administration is contraindicated and pulmonary embolism is suspected. |
Med |
| MRA pulmonary arteries |
4 |
If local expertise is available. See comments regarding contrast in the text below under "Anticipated Exceptions." |
None |
| US echocardiography transthoracic stress |
4 |
Alternative to stress nuclear medicine scan if cardiac etiology is suspected. |
None |
| INV, coronary angiography with ventriculography |
4 |
If stress testing is equivocal and a cardiac etiology is suspected. |
Med |
| CT coronary calcium |
4 |
A negative score may be useful for ruling out coronary etiology. |
Med |
| X-ray barium swallow and upper GI series |
3 |
If gastroesophageal disease is suspected. |
Med |
| X-ray rib views |
3 |
If a chest wall etiology is suspected. |
Med |
| X-ray thoracic spine |
3 |
If a spinal etiology is suspected. |
Med |
| US abdomen |
3 |
If abdominal pathology is suspected. |
None |
| MRA coronary arteries |
2 |
Not well developed. |
None |
| Rating Scale: 1=Least appropriate, 9=Most appropriate |
*Relative Radiation Level |
Note: Abbreviations used in the table are listed at the end of the "Major Recommendations" field.
Summary of Literature Review
Patients with signs and/or symptoms of acute coronary syndrome (ACS) are not included in this discussion as the evaluation and treatment algorithms have been well defined in the Scientific Statements and Practice Guidelines of the American Heart Association. The classic patient with suspected ACS presents to emergency departments with substernal chest pain, diagnostic ST segment changes, and elevated cardiac enzymes suggesting myocardial infarction. For those patients who do not present with classic ACS signs, symptoms, or electrocardiogram (ECG) abnormalities the differential diagnosis needs to include pulmonary, gastrointestinal (GI), or musculoskeletal pathologies. In these patients, noninvasive imaging methodologies are essential for diagnosis.
The following imaging modalities are available in evaluating patients presenting to the emergency departments with low probability of coronary artery disease (CAD): chest radiography, multidetector computed tomography (MDCT), magnetic resonance imaging (MRI), ventilation/perfusion (V/Q) scans, cardiac perfusion scintigraphy, transesophageal and transthoracic echocardiography, positron emission tomography (PET), spine and rib radiography, barium esophageal and upper GI studies, and abdominal ultrasound.
Chest Radiography
The chest radiograph is the recommended initial imaging study. Chest radiographs can diagnose pneumothorax, pneumomediastinum, fractured ribs, acute and chronic infections, and malignancies. Other conditions producing chest pain, such as aortic aneurysms/dissections and/or pulmonary emboli, may be suspected from the chest radiograph, but the overall sensitivities are less.
Thoracic calcifications, if present, may indicate pericardial disease, ventricular aneurysm, intracardiac thrombi, or aortic disease. The presence of a Hampton hump, Westermark sign, or pulmonary artery enlargement may suggest pulmonary embolism, while mediastinal air may indicate a ruptured viscus or subpleural bleb.
Multidetector Computed Tomography
MDCT has very high accuracy in demonstrating pneumothorax, pneumonia, malignancies, and pulmonary airspace disease. CT angiography (CTA) is the imaging modality of choice for suspected pulmonary embolism and aortic pathology such as dissection or aneurysm. Pericardial effusions, thickening, and/or calcifications are seen far more readily than with radiographs alone. Electrocardiogram (ECG) gated MDCT can be used in dedicated cardiac protocols for coronary CTA. This examination has a very high negative predictive value for CAD. When coronary CTA is performed with retrospective ECG-gating, wall motion and valve abnormalities can be identified via cine evaluations of CT images acquired throughout the cardiac cycle. Both prospective and retrospective ECG-gated cardiac CT can define ventricular aneurysms and cardiac thrombi. MDCT is also the primary method for diagnosing coronary anomalies. A coronary calcium score of zero can be useful in excluding CAD.
Transthoracic and Transesophageal Echocardiography
Transthoracic and transesophageal echocardiography with or without pharmacologic stress are frequently used to define abnormalities of ventricular wall motion as an indicator of cardiac disease. In addition, echocardiography can readily demonstrate pericardial effusion, valve dysfunction, and cardiac thrombus. Aortic pathology can be identified, but the findings of intramural hematoma, dissection, pulmonary embolus, and aneurysm are better seen with MDCT or MRI (discussed below).
Magnetic Resonance Imaging
Magnetic resonance angiography (MRA) can be performed with either noncontrast (e.g., time-of-flight, balanced gradient-echo) or contrast-enhanced (e.g., 3D arterial-phase fast gradient-echo) protocols that are useful in identifying vascular pathology. These techniques can be used to identify aortic as well as pulmonary artery pathology. MRA is typically more time-consuming and less available in the emergency setting, but is an important alternative noninvasive imaging strategy in patients with a contraindication to CTA. Cardiac MRI is uncommonly used in the emergency setting because of the relatively long scan times and the limited number of trained physicians, technologists, and MR resources.
Radiography of the Ribs, Cervical Spine, or Thoracic Spine
Rib or spine radiographs are indicated in patients with a clinical suspicion of skeletal pathology.
Radionuclide Studies
Radionuclide myocardial perfusion studies with thallium 201, technetium 99m sestamibi, or tetrofosmin are frequently used in identifying perfusion abnormalities as a cause for the chest pain, especially when a cardiac etiology is suspected. A normal stress perfusion scan may be used to exclude the diagnosis of coronary artery disease in patients who have ruled out myocardial infarction by enzymes.
PET is an alternative method for evaluating myocardial perfusion deficits, using N13 ammonia or rubidium 82 agents. However, these examinations are less commonly used because they are time consuming and resources are not readily available.
V/Q lung scintigraphy can be used in patients with clinically suspected pulmonary embolism, but this study has been largely replaced by MDCT.
Cardiac Catheterization
Cardiac catheterization with coronary digital subtraction angiography remains the gold standard in demonstrating CAD and can permit immediate therapeutic intervention. Catheterization has traditionally served as the definitive diagnostic test, although the high negative predictive value of coronary CTA enables it to be used alone to exclude CAD.
Barium Swallow or Endoscopy
Esophageal disorders can be the cause of chest pain. A barium swallow or endoscopy may be helpful in establishing esophageal spasm or reflux as an etiology of the chest pain.
Abdominal Ultrasonography
Abdominal ultrasound may be indicated in documenting cholecystitis as a cause for the chest pain. Ultrasound is also helpful in evaluating pancreatitis and/or intra-abdominal abscesses and fluid collections.
Summary
The patient's history is important in establishing the etiology in patients presenting to the emergency departments with a low probability of a cardiac etiology for their chest pain, and a number of imaging modalities may be required to establish the diagnosis. The chest radiograph is almost universally obtained. Traditionally, cardiac echo, stress perfusion scanning, and coronary angiography have been the mainstays for diagnosing coronary heart disease. MDCT is increasingly used in the evaluation of coronary disease. CTA, MRA, ventilation-perfusion scanning, barium swallow, and spine or rib radiographs play a role in evaluating noncoronary causes of chest pain.
Anticipated Exceptions
Nephrogenic systemic fibrosis (NSF, also known as nephrogenic fibrosing dermopathy) was first identified in 1997 and has recently generated substantial concern among radiologists, referring doctors and lay people. Until the last few years, gadolinium-based MR contrast agents were widely believed to be almost universally well tolerated, extremely safe and non-nephrotoxic, even when used in patients with impaired renal function. All available experience suggests that these agents remain generally very safe, but recently some patients with renal failure who have been exposed to gadolinium contrast agents (the percentage is unclear) have developed NSF, a syndrome that can be fatal. Further studies are necessary to determine what the exact relationships are between gadolinium-containing contrast agents, their specific components and stoichiometry, patient renal function and NSF. Current theory links the development of NSF to the administration of relatively high doses (e.g., >0.2mM/kg) and to agents in which the gadolinium is least strongly chelated. The U.S. Food and Drug Administration (FDA) has recently issued a "black box" warning concerning these contrast agents (http://www.fda.gov/Drugs/DrugSafety/PostmarketDrugSafetyInformationforPatientsandProviders/ucm142882.htm).
This warning recommends that, until further information is available, gadolinium contrast agents should not be administered to patients with either acute or significant chronic kidney disease (estimated glomerular filtration rate [GFR] <30 mL/min/1.73m2), recent liver or kidney transplant or hepato-renal syndrome, unless a risk-benefit assessment suggests that the benefit of administration in the particular patient clearly outweighs the potential risk(s).
Abbreviations
- CT, computed tomography
- CTA, computed tomography angiography
- GI, gastrointestinal
- INV, invasive
- MDCT, multidetector computed tomography
- Med, medium
- Min, minimal
- MRA, magnetic resonance angiography
- MRI, magnetic resonance imaging
- NUC, nuclear medicine
- Tc, technetium
- US, ultrasound
- V/Q, ventilation/perfusion scan
| Relative Radiation Level |
Effective Dose Estimated Range |
| None |
0 |
| Minimal |
<0.1 mSv |
| Low |
0.1-1 mSv |
| Medium |
1-10 mSv |
| High |
10-100 mSv |
