Cardiac Imaging Guide: Tool to help referring physicians order correct cardiac imaging test

Select Cardiac Imaging Application:
Symptomatic outpatient with potential new cardiovascular disease
Asymptomatic outpatient pre-operative evaluation
..
(SPECT) Treadmill nuclear myocardial perfusion study
Advantages
Single photon emission computed tomography (SPECT) myocardial perfusion imaging is a well-established study for both the detection and risk stratification of patients with known coronary heart disease. In addition to the highly prognostic functional and hemodynamic data derived from the treadmill portion of the study, the rest and stress perfusion images add significantly to the value of this study. Images reveal left ventricle chamber size, global and regional left ventricular function. Size, severity, and location of myocardial ischemia and/or myocardial infarction are also evaluated. In addition, if the patient is unable to achieve appropriate target endpoints (reproduction of symptoms, >85% max predicted HR) on the treadmill, the study can be rapidly converted to a pharmacologic study resulting in a diagnostic study.
Contraindications/Cautions
Unstable angina, decompensated heart failure, severe aortic stenosis. Cannot ingest caffeine containing products within 12 hrs if desire to have option to convert to pharmocologic study.
Study time
If weight < 250lbs in males or < 220lbs in females, 3 hrs in single day; if increased body habitus requires a 2 day study, 1.5 hrs each day
Order Statements
▸ Evaluate for myocardial ischemia in a patient with stable chest pain at intermediate risk for the presence of coronary artery disease.
▸ Risk stratification for patient at elevated risk of perioperative cardiovascular event who has an exercise tolerance under 4 metabolic equivalents
▸ Risk stratify patient with known coronary heart disease
Order Tips
SPECT ordering in EPIC at UW
(SPECT) Vasodilator nuclear myocardial perfusion study
Advantages
Single photon emission computed tomography (SPECT) myocardial perfusion imaging is a well-established study for both the detection and risk stratification of patients with known coronary heart disease. Images allow quantification of left ventricle chamber size, global and regional left ventricular function; and size, severity, and location of myocardial ischemia and/or myocardial infarction.
Contraindications/Cautions
Unstable angina, decompensated heart failure, severe aortic stenosis. No caffeine containing products for 12 hrs prior to study.
Study time
If weight < 250lbs in males or < 220lbs in females, 3 hrs in single day; if increased body habitus requires a 2 day study, 1.5 hrs each day
Order Statements
▸ Evaluate for myocardial ischemia in a patient with stable chest pain at intermediate risk for the presence of coronary artery disease who cannot walk or exercise.
▸ Risk stratification for patient at elevated risk of perioperative cardiovascular event who has an exercise tolerance under 4 metabolic equivalents and cannot ambulate or exercise
▸ Risk stratify patient who is unable to exercise with known coronary heart disease
Order Tips
SPECT ordering in EPIC at UW
(PET) Vasodilator myocardial perfusion study
Description
A position emission tomography (PET) stress test is a noninvasive nuclear imaging test that is used to assess for ischemia. PET has a higher spatial resolution and detection efficiency compared to SPECT leading to higher sensitivity, specificity, and diagnostic certainty. It should be considered for patients who are morbidly obese or with complex coronary artery disease. Reimbursement by insurance is usually covered in patients with history of coronary artery disease or other indeterminate stress testing (SPECT or echo).
Advantages
Very high sensitivity and specificity; Allows for quantification of myocardial blood flow; Short imaging time (20 minutes); Minimal radiation exposure
Contraindications/Cautions
Unstable angina or severe aortic stenosis; No caffeine for 12 hr prior to study
Study time
Patient should plan on 1 hr appointment, but total imaging time is only 20 minutes.
Order Statements
▸ Evaluate for myocardial ischemia in a patient with stable chest pain at intermediate risk for the presence of coronary artery disease who cannot walk or exercise and has either increased BMI or prior alternative non-diagnostic imaging study
▸ Risk stratification for patient at elevated risk of perioperative cardiovascular event who has an exercise tolerance under 4 metabolic equivalents, cannot ambulate or exercise, and has either increased BMI or prior alternative non-diagnostic imaging study
▸ Risk stratify patient who is unable to exercise with known coronary heart disease
Order Tips
PET ordering in EPIC at UW
Cardiac MRI
Advantages
No restriction in imaging planes. Ability to distinguish various types of cardiomyopathy. Tissue characterization for cardiac masses. Viability assessment. Evaluation of valvular heart disease without invasiveness of transesophageal echo.
Cautions
Clautrophobia, decompensated heart failure unable to lay flat, any cause of difficulty with breath holding, Gadolinium contrast can only be used with extreme caution in end stage renal disease.
Contraindication
PA catheter, imbedded ferromagnetic metal, CIED (Pacemaker/defibrillator) some exceptions made. Prior anaphylactic allergy to gadolinium. Inability to hold breath. Inability to follow breathing instructions.
Study time
45 min to 1.5 hours
Order Statement
Evaluate for etiology of cardiomyopathy. Viability prior to revascularization.
Order Tips
MRI ordering in EPIC at UW
Vasodilator Cardiac MRI stress perfusion imaging
Descriptor
Cardiac magnetic resonance imaging is a special MRI study of the heart that allows for evaluation of cardiac function and scar/fibrosis/edema and can also be performed with a vasodilator stress agent.
Advantages
High resolution images of cardiac function, wall motion analysis, presence of scar/fibrosis/edema, and does not require ionizing radiation. Excellent images in morbidly obese patients as long as patient chest can fit into MRI.
Cautions
Longer study that requires ability to cooperate with study and hold breath for 8-12 seconds at a time. Many patients experience claustrophobia with MRI studies. Fast heart rate is not a problem, but irregular heart rhythms such as atrial fibrillation can severely impair imaging quality.
Contraindication
Prior anaphylactic reaction to gadolinium based contrast. Stage IV - V chronic kidney disease or end stage renal disease have low but potential risk of nephrogenic systemic fibrosis. Outside of certain exceptions, patients with pacemakers and defibrillators generally cannot be scanned.
Study time
1 hour
Order Statements
▸ Evaluate for myocardial ischemia in a patient with stable chest pain at intermediate risk for the presence of coronary artery disease who cannot walk or exercise and has either increased BMI or prior alternative non-diagnostic imaging study
▸ Risk stratification for patient at elevated risk of perioperative cardiovascular event who has an exercise tolerance under 4 metabolic equivalents, cannot ambulate or exercise, and has either increased BMI or prior alternative non-diagnostic imaging study
Order Tips
Not currently available.
Coronary CT Angiogram
Descriptor
Coronary CT angiography (CCTA) is a CT scan of the heart specially protocoled to evaluate the coronary arteries for stenosis and plaque.
Advantages
NOT contraindicated in patients with defibrillators or pacers; Claustrophobia is not usually problematic; Excellent anatomic detail of coronary artery anatomy; Luminal stenosis and calcium burden quantification are both possible
Cautions
Iodinated contrast is potentially nephrotoxic and should be avoided in patients with tenuous renal function or end stage renal disease on dialysis that is expected to improve; Uses Ionizing radiation; Irregular arrhythmias (atrial fibrillation or other irregular rhythm can be problematic; Tachycardia (ideally HR <60-70 BPM)
Contraindication
Prior anaphylactic reaction to iodinated contrast
Study time
less than 30 min
Order Statement
▸ Evaluate for coronary artery stenosis in a patient with stable chest pain at intermediate risk for the presence of coronary artery disease who cannot walk or exercise.
Order Tips
CT ordering in EPIC at UW
Vascular CT Angiogram
Advantages
NOT contraindicated in patients with defibrillators or pacers; Claustrophobia is not usually problematic; Excellent anatomic detail of coronary artery anatomy; Calcium burden of the aorta and valves; Orthogonal measurements to evaluate stenosis or aneurysm; Valve opening and closing can be evaluated for surgical planning
Cautions
Abnormal renal function; Pregnant patients; Uses ionizing radiation; Arrhythmias can be problematic for ECG gating
Contraindication
Prior anaphylactic reaction to iodinated contrast
Study time
less than 30 min
Order Statements
Prior aortic surgery (such as Bental); Evaluate aortic aneurysm; Concern for aortic dissection; Collagen vascular disease
Treadmill Stress Test (no imaging)
Advantages
no IV required
Contraindications/Cautions
Unstable angina, unstable arrhythmia, or severe aortic stenosis; uninterpretable baseline EKG (left bundle branch block, ST abnormalities)
Study time
30 minutes
Order Statements
▸ Evaluate for myocardial ischemia in a patient with stable chest pain at intermediate risk for the presence of coronary artery disease.
▸ Risk stratification for patient at elevated risk of perioperative cardiovascular event who has an exercise tolerance under 4 metabolic equivalents
▸ Evaluate for myocardial ischemia in pt with risk factors
▸ Risk stratify pt with known coronary heart disease
Order Tips
Not available yet
Treadmill Echo
Description
Exercise stress test in which the patient exercises on a treadmill at increasing workload, usually according to the Bruce protocol. A limited echocardiogram is obtained at rest, before exercise, to evaluate baseline left ventricular wall motion. Immediately following peak exercise, repeat echo images are acquired to evaluate for ischemia-induced wall motion abnormalities. Exercise capacity and hemodynamic response (changes in BP and HR) to exercise also hold prognostic value
Advantages
Can be combined with full echocardiogram; can be combined with assessment of stress-induced diastolic dysfunction or valvular abnormalities; often does not require IV*; high sensitivity and specificity; relatively inexpensive
Contraindications/Cautions
Unstable angina, unstable arrhythmia, or severe aortic stenosis
Study time
1 hour
Order Statements
▸ Evaluate for myocardial ischemia in a patient with stable chest pain at intermediate risk for the presence of coronary artery disease
▸ Risk stratification for patient at elevated risk of perioperative cardiovascular event who has an exercise tolerance under 4 metabolic equivalents
▸ Evaluate for myocardial ischemia in pt with risk factors
▸ Risk stratify pt with known coronary heart disease
Order Tips
echo ordering in EPIC at UW
*for difficult visualization of left ventricular wall segments, an IV is placed for echocardiographic enhancement agent (called echo contrast), which consists of microbubbles and contains no iodine or radioactive material.  It is not toxic to the kidneys
Exercise Echo (not treadmill)
Description
Exercise stress test in which the patient exercises on a supine bicycle at increasing workload, according to a standardized protocol. A limited echocardiogram is obtained at rest, before exercise, to evaluate baseline left ventricular wall motion. Immediately following peak exercise, repeat echo images are acquired to evaluate for ischemia-induced wall motion abnormalities. Exercise capacity and hemodynamic response (changes in BP and HR) to exercise stress also hold prognostic value.
Advantages
Can be combined with full echocardiogram; can be combined with assessment of stress-induced diastolic dysfunction or valvular abnormalities; often does not require IV*; high sensitivity and specificity; relatively inexpensive
Contraindications/Cautions
Unstable angina, unstable arrhythmia, or severe aortic stenosis; often difficult to achieve adequate exercise workload on bicycle
Study time
1 hour
Order Statements
▸ Evaluate for myocardial ischemia in a patient with stable chest pain at intermediate risk for the presence of coronary artery disease who cannot walk but can exercise.
▸ Risk stratification for patient at elevated risk of perioperative cardiovascular event who has an exercise tolerance under 4 metabolic equivalents and cannot ambulate
▸ Evaluate for myocardial ischemia in pt with risk factors
▸ Risk stratify pt with known coronary heart disease; patient unable to walk on treadmill
Order Tips
Echoordering in EPIC at UW
*for difficult visualization of left ventricular wall segments, an IV is placed for echocardiographic enhancement agent (called echo contrast), which consists of microbubbles and contains no iodine or radioactive material.  It is not toxic to the kidneys
Dobutamine Stress Echo
Description
Pharmacologic stress test in which dobutamine is infused at escalating doses until a target heart rate is achieved. A limited echocardiogram is obtained prior to starting dobutamine to evaluate baseline left ventricular wall motion. Echo images are then acquired at a low-dose of dobutamine, at peak heart rate, and during recovery to evaluate for ischemia-induced wall motion abnormalities. Low-dose dobutamine stress echo can also be used to evaluate for myocardial viability.
Advantages
Can be combined with full echocardiogram; can be combined with assessment of stress-induced valvular abnormalities; high sensitivity and specificity
Contraindications/Cautions
Unstable angina, unstable arrhythmia, or severe aortic stenosis; may precipitate arrhythmias, NPO 4+ hours.
Study time
Stress time < 30 minutes, total patient experience about 90 minutes
Order Statements
▸ Evaluate for myocardial ischemia in a patient with stable chest pain at intermediate risk for the presence of coronary artery disease who cannot walk or exercise
▸ Risk stratification for patient at elevated risk of perioperative cardiovascular event who has an exercise tolerance under 4 metabolic equivalents and cannot ambulate or exercise
▸ Risk stratify pt with known coronary heart disease; patient unable to exercise.
Order Tips
Echo ordering in EPIC at UW
Echo for stable new onset heart failure or arrhythmia
Description
Ultrasound imaging modality that is a non-invasive, portable, and does not involve radiation. Useful for evaluating cardiac structure and function, including some assessment of hemodynamics. A comprehensive exam includes left and right ventricular size and function (for question of systolic or diastolic heart failure), regional wall motion abnormalities (which could indicate coronary artery disease), valvular structure and function (eg. for possible aortic stenosis), pericardial effusion, volume status, pulmonary pressures, and limited views of the aorta (best for aortic root).
Advantages
portable; readily available; completely non-toxic; characterization of anatomy and pathophysiology: chamber size and systolic and diastolic function, wall motion abnormalities, valvular morphology and function, filling pressures, pulmonary pressures, pericardium, selected portion of the great vessels; relatively inexpensive
Contraindications/Cautions
image quality can be compromised by lung disease, obesity. Transesophageal echo may be necessary to evaluate valvular disease, echocardiographic enhancement agent can be used to define size, function and wall motion abnormalities in patients with difficult images
Study time
1 hour to 90 minutes
Order Statement
heart failure; CHF; dyspnea; edema OR arrhythmia (specify rhythm disturbance)
Order Tips
Echo ordering in EPIC at UW
Echo for pre-operative evaluation
Description
Ultrasound imaging modality that is a non-invasive, portable, and does not involve radiation. Useful for evaluating cardiac structure and function, including some assessment of hemodynamics. A comprehensive exam includes left and right ventricular size and function (for question of systolic or diastolic heart failure), regional wall motion abnormalities (which could indicate coronary artery disease), valvular structure and function (eg. for possible aortic stenosis), pericardial effusion, volume status, pulmonary pressures, and limited views of the aorta (best for aortic root).
Advantages
no IV required
Contraindications/Cautions
Unstable angina, unstable arrhythmia, or severe aortic stenosis; uninterpretable baseline EKG (left bundle branch block, ST abnormalities)
Study time
30 minutes
Order Statement
Evaluate for myocardial ischemia; Evaluate for myocardial ischemia in pt with risk factors; Risk stratify pt with known coronary heart disease prior to operation
Order Tips
Echo ordering in EPIC at UW
Echo for significant murmur
Description
Ultrasound imaging modality that is a non-invasive, portable, and does not involve radiation. Useful for evaluating cardiac structure and function, including some assessment of hemodynamics. A comprehensive exam includes left and right ventricular size and function (for question of systolic or diastolic heart failure), regional wall motion abnormalities (which could indicate coronary artery disease), valvular structure and function (eg. for possible aortic stenosis), pericardial effusion, volume status, pulmonary pressures, and limited views of the aorta (best for aortic root).
Advantages
portable; readily available; non-toxic; characterization of anatomy and pathophysiology: chamber size and systolic and diastolic function, wall motion abnormalities, valvular morphology and function, filling pressures, pulmonary pressures, pericardium, selected portion of the great vessels; relatively inexpensive
Contraindications/Cautions
image quality can be compromised by lung disease, obesity. Transesophageal echo may be necessary to evaluate valvular disease, echocardiographic enhancement agent can be used to define size, function and wall motion abnormalities in patients with difficult images
Study time
1 hour to 90 minutes
Order Statement
murmur, evaluate for valvular disease
Order Tips
Echo ordering in EPIC at UW
Echo for surveillance of cardiovascular disease, incidentally found aortic aneurysm or collagen vascular disease with known aortopathy
Description
Ultrasound imaging modality that is a non-invasive, portable, and does not involve radiation. Useful for evaluating cardiac structure and function, including some assessment of hemodynamics. A comprehensive exam includes left and right ventricular size and function (for question of systolic or diastolic heart failure), regional wall motion abnormalities (which could indicate coronary artery disease), valvular structure and function (eg. for possible aortic stenosis), pericardial effusion, volume status, pulmonary pressures, and limited views of the aorta (best for aortic root).
Advantages
portable; readily available; non-toxic; characterization of anatomy and pathophysiology:  selected portion of the great vessels (aortic root, proximal ascending, arch, proximal descending, portion of distal descending, abdominal, main pulmonary artery); relatively inexpensive
Contraindications/Cautions
Entire aorta not visualized; image quality compromised by lung disease, obesity. Transesophageal echo provides more reliable and comprehensive views of great vessels.
Study time
1 hour to 90 minutes
Order Statement
evaluate size of aortic aneurysm; evaluate aortic dilatation; assess for thoracic aortic aneurysm (list underlying disease predisposing to aortopathy)
Order Tips
Echo ordering in EPIC at UW
Pre-test probability of CAD in patient with stable chest pain
Age (yrs)
Gender
Chest PainTypical chest pain is defined as 1) substernal chest pain or discomfort, that is 2) provoked by exertion or emotional stress and 3) relieved by rest and/or nitroglycerine.
Atypical chest pain is defined as two of the before mentioned criteria.
If one or none of the criteria is present, symptoms are classified as non-specific.
Basic Risk:
DiabetesDefined as fasting glucose levels of ≥126 mg/dL (≥7 mmol/L) or treatment with either diet intervention, oral glucose lowering agent or insulin
DyslipidaemiaDefined as a total cholesterol ≥200 mg/dL (≥5.2 mmol/L) or treatment with lipid-lowering drugs
HypertensionDefined as a blood pressure ≥140/90 mmHg or the use of antihypertensive medication
Current or Past Smoker
Clinically Augmented Risk:
Based on Genders et al. Prediction model to estimate presence of coronary artery disease, BMJ 2012.
Pre-op assessment using the Revised Cardiac Risk Index
High Risk Surgery?Defined as: Intraperitoneal, intrathoracic, or suprainguinal vascular
Coronary Artery Disease?Defined as: History of myocardial infarction, positive exercise test, current complaint of ischemic chest pain or use of nitrate therapy, or ECG with Q waves. Patients with prior CABG surgery or PTCA are included only if they had current complaints of chest pain that are presumed to be due to ischemia
Congestive Heart Failure?History of congestive heart failure, pulmonary edema, or paroxysmal nocturnal dyspnea; physical examination showing bilateral rales or S3 gallop; or chest radiograph showing pulmonary vascular redistribution
Cerebrovascular Disease?History of transient ischemic attack or stroke
Diabetes Mellitus on Insulin?
Serum Creatinine >2 mg/dl or >177 μmol/L?
Risk of adverse outcome with non-cardiac surgery
Estimated risk of Myocardial Infarction, Pulmonary Edema, Ventricular Fibrillation, Cardiac Arrest, or Complete Heart Block
Based on Fleisher et al. 2009 ACCF/AHA focused update on perioperative beta blockade incorporated into..., Circulation 2009.

Purpose: Cardiovascular imaging has grown exponentially in terms of the complexity and breadth of available testing. With the expansion of available options, appropriate test selection has become increasingly challenging. This cardiac imaging tool was created by a multidisciplinary group of experts in cardiovascular imaging to present a unified approach to cardiovascular imaging. The goal of this tool is to serve as both an educational reference as well as a point of care tool for the selection and ordering of cardiac imaging within the University of Washington.

Contact: For questions about studies at UW Medicine, contact the cardiac imaging consult pager 206-597-3367 or send questions to cardiac_imaging_consult@uw.edu.

Disclaimer: This is an educational tool to supplement the cardiac imaging ordering process and does not replace clinical judgment or supersede established management protocols.

References: ▸ Stable Ischemic Heart Disease Guidelines
▸ Heart Failure Guidelines; Updates on Therapy; Updates on Management

Developed by members of Cardiology and Radiology, UW Medical Center

Team: James Lee, Richard Cheng, Tiffany Chen, Laurie Soine, James Kirkpatrick, Rachael Edwards, Adam Alessio

Created: 25 June 2016, Last Revised: 14 June 2017
Copyright © 2016, University of Washington, aalessio@uw.edu, All rights reserved.