In this presentation we will discuss different techniques of MDCT Cardiac imaging to role out different causes of chest pain to help cardiologist in management of the patient.
We shall discuss it case by case.
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Role of mdct angio in management of acute chest pain Dr. Muhammad Bin Zulfiqar
1. Role of MDCT Angio in
Management of Acute Chest Pain
Dr. Muhammad Bin Zulfiqar
PGR IV FCPS Services Institute of
Medical Sciences / Hospital
radiombz@gmail.com
2. Objectives
• To look for MDCT Utility in Cardiac Emergency.
• Its role to characterize ACS.
• Effect on hospital stay and expenditure.
• To look for future cardiac risk factors.
• To stop inadvertent interventions.
3. Usual Presentations
• The most clinically relevant conditions
– coronary artery disease presenting as acute coronary
syndrome
– pulmonary embolism
– Acute aortic syndrome
– Other Causes of Chest pain
• Pneumonia
• Pleurisy
• musculoskeletal
Truong et al. Coronary CT Angiography Versus Standard Emergency Department Evaluation for Acute Chest Pain and Diabetic Patients: Is
There Benefit With Early Coronary CT Angiography? J Am Heart Assoc. 2016;5:e003137
Bastarrika et al. Cardiac CT of Acute Chest Pain. AJR 2009; 193:397–409
Helpren E.J. Triple-Rule-Out CT Angiography for Evaluation of Acute Chest Pain and Possible Acute Coronary Syndrome. Radiology: Volume
252: Number 2—August 2009
4. Definition of ACS
• Constellation of clinical symptoms that are
compatible with acute myocardial ischemia
– STEMI
– NSTEMI
– Unstable Angina (UA)
J Am Coll Cardiol. 2007 Aug 14;50(7)
5. Classic Initial Approach
• Detailed patient history
• Physical examination
• ECG
• Measurement of cardiac biomarkers.
Bastarrika et al. Cardiac CT of Acute Chest Pain. AJR 2009; 193:397–409
6. Thrombosis in Myocardial Infarction
(TIMI) risk score
One point to each the following risk factors:
1. Age greater than 65 years
2. known coronary artery disease (documented
previous coronary artery stenosis > 50%)
3. Severe angina (more than two episodes of
chest pain in the preceding 24 hours)
4. St segment changes (persistent depression
or transient elevation) on admission ECG
Bastarrika et al. Cardiac CT of Acute Chest Pain.
AJR 2009; 193:397–409
7. Thrombosis in Myocardial Infarction
(TIMI) risk score
5. Elevated serum markers of myocardial
ischemia (troponins)
6. Use of aspirin in the 7 days before
presentation
7. Three or more conventional risk factors for
coronary artery disease
– (family history, diabetes mellitus, hypertension,
hypercholesterolemia, smoking).
Bastarrika et al. Cardiac CT of Acute Chest Pain.
AJR 2009; 193:397–409
8. Risk Factor Stratification
• High risk (TIMI score, 5–7)
– usually are referred without delay for urgent
coronary angiography and intervention
• Intermediate risk (TIMI score, 3–4)
• Low risk (TIMI score, 0–2)
– Admitted for observation and undergo serial ECG
and cardiac biomarker testing followed by stress
testing.
Thrombosis in Myocardial Infarction (TIMI) risk score
Bastarrika et al. Cardiac CT of Acute Chest Pain. AJR 2009; 193:397–409
9. MDCT Techniques / Protocols
• CT coronary angiogram
• "Triple rule-out” coronary CT angiography
• CT perfusion
Truong et al. Coronary CT Angiography Versus Standard Emergency Department Evaluation for Acute Chest Pain and
Diabetic Patients: Is There Benefit With Early Coronary CT Angiography? J Am Heart Assoc. 2016;5:e003137
Bastarrika et al. Cardiac CT of Acute Chest Pain. AJR 2009; 193:397–409
Helpren E.J. Triple-Rule-Out CT Angiography for Evaluation of Acute Chest Pain and Possible Acute Coronary Syndrome.
Radiology: Volume 252: Number 2—August 2009
10. Patient Selection Criteria
• Low to moderate risk of ACS
• Non ACS diagnosis
• Negative biomarkers
– Troponin-I
– Myoglobin
• Normal ECG or non specific changes
• No history to suggest extensive coronary
calcium
Helpren E.J. Triple-Rule-Out CT Angiography for Evaluation of Acute Chest Pain and Possible Acute
Coronary Syndrome. Radiology: Volume 252: Number 2—August 2009
11. Careful consideration / Exclusion
• Abnormal renal function tests.
• Patients with stents and bypass
• H / O allergy to tolerate CT
• Abnormal cardiac rythems.
Helpren E.J. Triple-Rule-Out CT Angiography for Evaluation of Acute Chest Pain and
Possible Acute Coronary Syndrome. Radiology: Volume 252: Number 2—August 2009
12. Reconstruction Techniques
• Multiplanar Reformation.
• Curved Multiplanar Reformation
• Maximum Intensity Projection
• Volume Rendering
Helpren E.J. Triple-Rule-Out CT Angiography for Evaluation of Acute Chest Pain and
Possible Acute Coronary Syndrome. Radiology: Volume 252: Number 2—August 2009
13. Case 1
• 52-year-old woman with acute atypical chest
pain.
• Study allowed to noninvasively rule-out
pulmonary embolism, acute aortic syndrome,
and coronary artery disease with single scan
• Contrast-enhanced retrospectively ECG-gated
thoracic CT angiogram done which showed
normal findings.
16. Case 1
• Curved multiplanar reformatted
image shows left anterior
descending coronary artery,
right coronary artery, and
circumflex artery.
17. Case 2
• 50-year-old man with acute chest pain, family
history of coronary artery disease,
intermediate cardiovascular risk, and normal
initial cardiac biomarker and ECG results
referred for CT imaging
18. Case 2
• (Right) Curved MPR and (Left) volume rendered images show calcified
plaques causing nonsignificant stenosis in mid segment of artery.
Arrowhead indicates intramyocardial course in distal segment.
20. Case 3
• Right. Axial contrast-enhanced image shows bilateral
central pulmonary emboli (arrowheads).
• Left. Axial reformatted volume-rendered color-mapped
image shows pulmonary hypo perfused areas
(arrowheads) mainly at upper lobes.
21. Case 3
• Right and Left, Axial CT image at midheart level (right)
and right ventricular end-diastolic volumetric analysis
(left) show right ventricular (RV) enlargement and
septal flattening indicating right ventricular pressure
overload.
22. Case 4
• 53-year-old woman with acute chest pain
radiating to back and dyspnoea.
• Thoracic CT angiography suggested.
24. Case 4
• Volume-rendered image
shows origination of
dissection (arrowhead)
distal to left subclavian
artery and extension
into abdominal aorta.
25. Case 5
• 43-year-old man with intermediate
cardiovascular risk and acute chest pain.
• Thoracic CT angiography done
26. Case 5
• Curved MPR (Right) and volume-rendered (Left) images of left
anterior descending coronary artery show intense vascular
remodeling of entire vessel with significant stenosis caused by
predominantly noncalcified plaque (arrow) involving mid and distal
segments.
31. Case 8
• 58-year-old man admitted in emergency
department because of acute chest pain
radiating to back.
• Suspicion was aortic dissection.
• Thoracic CT angiography done
32. Case 8
• Right Contrast-enhanced axial CT image shows involvement
of ascending and descending aorta (arrows).
• Left Contrast-enhanced axial CT image shows flap with
whirl-like complex structure at aortic arch.
33. Case 9
• 24-year-old woman with history of Marfan
syndrome who presented with acute onset of
chest pain radiating into the neck. Clinical
suspicion was high for aortic dissection with
possible extension into coronary arteries or
great arteries in the neck.
• Thoracic CT angiography done on TRO
Extended Protocol
34. Case 9
• Right. Coronal maximum intensity projection (MIP) image
demonstrates enhancement of aorta, pulmonary arteries, and great
vessels extending from the aortic arch with no dissection.
• Left Oblique MIP image demonstrates normal aortic arch and
descending thoracic aorta.
35. Case 9
• Right Oblique coronal MIP image demonstrates normal left ventricular
outflow tract extending into proximal part of aortic arch. However, there is
air in tissues of the neck surrounding great vessels (arrows). Left Coronal
MIP image through the trachea demonstrates extensive free air in soft
tissue planes.
36. Case 10
• 37-year-old woman with no relevant cardiac
history presented with sudden onset of chest
pain while at work.
• Thoracic TRO angiography done.
37. Case 10
• MIP images of (right) left anterior descending artery in long axis of
the aortic root and (left) left anterior descending artery in
orthogonal obliquity in the short axis of the aortic root.
• 75% stenosis of the left anterior descending artery (arrow).
38. Raff G.L. et.al. SCCT guidelines on the use of coronary computed tomographic angiography for patients presenting with acute chest pain to the
emergency department: A Report of the Society of Cardiovascular Compute Tomography Guidelines Committee. J o u rnal of Ca r d i o v a s c u l
a r Computed Tomography 8 ( 2 0 1 4 ) 2 5 4e2 7 1
39. Markedly elevated calcium score
• (Right) Axial image at a slightly lower level demonstrates
calcification in the LAD, circumflex, and RCA. Mild calcification is
also identified in the posterior mitral annulus (arrowhead). (Left)
Calcium in the three major coronary arteries is color-coded. The
mitral annular calcification is labeled in pink and is not included in
the calcium score. The total Agatston calcium of 2726.1 is markedly
elevated, suggesting increased risk for a coronary event.
40.
41. Pitfalls In MDCT Cardiac Imaging
• Image quality suffers from fast heart rate
– Requires premedication with β-blockers
• Arrhythmias, ectopy, or ECG artifacts result in
degradation of image quality
– ECG-gating critical to coronary imaging
• Radiation dose to patient
• Provides anatomic information, and debates
about physiologic data
Chinnaiyan KM, et al. Cardiol Clin. 2009 Nov;27(4):587-96.
42. Take Home Message
• Provides excellent spatial resolution provides
superior information of anatomy
• Provides functional information through blood
perfused volume and stress protocols
• Ability for plaque analysis
• Appropriate use of Triple-Rule-Out Protocol can
explore other differential diagnoses for chest
pain
• MDCT imaging protocols incorporated into ACS
workup demonstrates savings in time to
diagnosis, costs while providing good patient
outcomes
Braunwald E, Antman EM, Beasley JW, et al. Circulation 2002; 106:1893–1900
CT coronary angiogram
Most of the studies evaluating the usefulness of CT imaging have used 64 multislice CT scanning with ECG gating to assess the lumen of coronary arteries. Using this technique, a sensitivity of 92% and specificity of 76% was achieved, even in patients who were initially ECG and troponin negative 2.
"Triple rule-out” coronary CT angiography
Some institutions are using this protocol that examines for not only coronary artery disease, but also aortic dissection, pulmonary embolism, and other chest diseases. While there is a consensus about its offering advantages in evaluating emergency department patients presenting with symptoms consistent with acute coronary syndrome, there is an ongoing debate about proper indications. It should not be used routinely and lacks demonstration of increasing efficiency or resource use 10,11.
CT perfusion
In patients who have established coronary artery narrowing, CT perfusion can be used to predict the significance of the luminal narrowing as well as predicting post infarction myocardial viability/salvageability 3-4.
An acute myocardial infarct would manifest with a reduced first pass effect (hypodense myocardium). A CT thoracic aortogram is in effect a cardiac first pass perfusion study (albeit, without the ECG gating) and has the potential to detect large territory myocardial infarcts. Despite these described findings, the role of CT perfusion in assessing acute myocardial infarction has not been well established.
An established myocardial infarct would manifest with:
delayed enhancement (7-15 minutes post CT contrast dose) 4
delayed peak enhancement occurs slightly later compared to normal myocardium 12.8 versus 11.6 seconds 8
peak enhancement is lowest in infarcts (26 HU) versus ischaemia (36 HU) versus normal myocardium (58 HU) 8
Infarct scars can mimic acute myocardial infarcts as they demonstrate a similar enhancement pattern, however, old infarcts are often associated with myocardial thinning and contour abnormality (bulges away from ventricle), useful distinguishing features.
One study has assessed the utility of non-ECG gated 16 slice CT pulmonary angiogram in detecting myocardial infarct. This method suffers from a few problems. Firstly, the relatively early (cf with CT aortogram/coronary angiogram) phase results in non-homogeneous enhancement of the myocardium. Secondly, streak artefact (consider saline chaser) from the undiluted contrast in the SVC / right atrium caused "pseudoareas" of reduced myocardial attenuation. Thirdly, movement artefact from the beating heart caused areas of increased/decreased attenuation. Despite these problems, this study published optimistic figures of 66.6%(sensitivity) and 91.4% (specificity) 5.
Approaches using dual-energy CT to visualize late myocardial enhancement as a marker for scars showed only a limited diagnostic value in comparison to MRI
—This technique is
most often used to generate cross-sectional images
of coronary arteries or other typical views,
such as short-axis or long-axis views. The image
plane can be chosen arbitrarily.
.—This
postprocessing algorithm allows the depiction of
the entire course of a coronary artery on a single
image. The image plane is adjusted to follow the
centerline of the vessel. The resultant display is
most useful for depicting the lumen of a coronary
artery from its ostium to its distal end.
Images can
be displayed singly (as individual sections) or
stacked (as a summary of several adjacent sections).
Stacked display results in loss of detail but
improved image contrast and decreased image
noise. Maximum intensity projection (MIP) allows
visualization of longer lengths of the coronary
lumen and has proved more accurate for the
detection of significant coronary artery lesions
than has multiplanar reformation or three-dimensional
(3D) volume rendering (22).
Volume rendering involves
reconstruction of the entire volume of image
data and display of the data from a selected
viewer orientation. The contributions of each
voxel along a line from the viewer’s eye through
the data set are summed, pixel by pixel, to obtain
a single composite image. This technique is most
useful for detecting coronary artery anomalies,
and it may be useful also for surgical planning
(22,23).
RG f Volume 26 ● Number 4 Hoffmann et al 965
RadioGraphics
Teaching
Point
TRO demonstrated a smooth 75% stenosis of the left anterior descending
artery (arrow).