Imaging
Thoracic Aortic Aneurysm
- Preliminary Diagnosis: Thoracic Aortic Aneurysm
-
I. What imaging technique is first-line for this diagnosis
- II. Describe the advantages and disadvantages of this technique for diagnosis of thoracic aortic aneurysm.
-
III. What are the contraindications for the first-line imaging technique?
-
IV. What alternative imaging techniques are available?
- V. Describe the advantages and disadvantages of the alternative techniques for diagnosis of thoracic aortic aneurysm.
- VI. What are the contraindications for the alternative imaging techniques?
Preliminary Diagnosis: Thoracic Aortic Aneurysm
I. What imaging technique is first-line for this diagnosis
Computed tomographic angiography (CTA). A non-contrast CT may be necessary to differentiate thrombus calcification, a common finding in aortic aneurysms, from displaced calcified intima associated with aortic dissection.
II. Describe the advantages and disadvantages of this technique for diagnosis of thoracic aortic aneurysm.
Advantages
Diagnostic and gives precise information regarding the size, shape, and location of the aneurysm
May diagnose other pathological processes that mimic an aneurysm on a chest radiograph, such as a mass.
Relatively quick
Requires minimal patient cooperation and is less susceptible to motion artifact
Disadvantages
Exposes the patient to a large amount of ionizing radiation.
Intravenous contrast may cause nephropathy or renal failure.
Risk of contrast-induced allergic reaction.
III. What are the contraindications for the first-line imaging technique?
Patients with known contrast allergy.
Contraindicated in pregnant women, especially within the first two trimesters.
IV. What alternative imaging techniques are available?
MRI with contrast.
Transthoracic or transesophageal ultrasound.
AP and lateral chest radiographs.
Conventional angiography.
V. Describe the advantages and disadvantages of the alternative techniques for diagnosis of thoracic aortic aneurysm.
Magnetic resonance imaging (MRI) with contrast
Advantages
Does not make use of ionizing radiation.
Can be used to diagnose or exclude other pathological processes within the chest.
Disadvantages
Expensive.
Time-consuming.
Requires marked patient cooperation to limit motion artifact.
Difficult study for claustrophobic individuals.
Requires that patient have good renal function with GFR > 60.
Intravenous contrast is associated with nephrogenic systemic fibrosis.
Transthoracic or transesophageal ultrasound
Advantages
May be diagnostic.
Can distinguish that it is a vascular structure and not a mass.
Relatively inexpensive.
Does not use ionizing radiation.
Transesophageal ultrasound produces better images of the thoracic aorta than transthoracic ultrasound.
Disadvantages
Resolution may be poor in obese patients.
Transesophageal ultrasound is relatively invasive and has a risk of esophageal perforation.
AP and lateral chest radiographs
Advantages
Can demonstrate the prominence of the aorta consistent with an aortic aneurysm, particularly if there are mural calcifications.
Inexpensive.
Performed quickly.
Disadvantages
Much less specific and sensitive than CT.
Conventional angiography
Advantages
Diagnostic.
Can be therapeutic if direct intraluminal catheter thrombolysis is indicated.
Disadvantages
More invasive with higher morbidity, i.e., bleeding, infection, dissection of vessel wall.
Does not demonstrate anatomical detail beyond vessels of interest like CT or MRI.
Requires use of iodinated contrast.
Requires high dose of ionizing radiation.
Expensive.
Requires fluoroscopy suite and interventional radiologist to perform the exam.
Sedation is recommended.
VI. What are the contraindications for the alternative imaging techniques?
MRI with contrast
Contraindicated in patients with non-MRI compatible devices, i.e., patients with embedded metallic devices not made of titanium, such as cardiac pacers, stents, and other non-MR approved metallic devices which may not enter the magnet for imaging.
Transthoracic ultrasound
No significant contraindications for transthoracic ultrasound.
Transesophageal ultrasound
Due to the relatively invasive nature of the exam, prior surgery of the oropharynx or esophagus may be contraindications, particularly if the surgery was recent.
Due to the relatively invasive nature of the exam, neoplastic, infectious, or inflammatory processes involving the oropharynx or esophagus may be contraindications.
PA and lateral chest radiographs
No significant contraindications. Some institutions require informed consent for pregnant patients.
Conventional angiography
Coagulopathy, i.e., bleeding diathesis.
Pregnancy.
Creatinine > 1.6.
Allergy.
Copyright © 2017, 2014 Decision Support in Medicine, LLC. All rights reserved.
No sponsor or advertiser has participated in, approved or paid for the content provided by Decision Support in Medicine LLC. The Licensed Content is the property of and copyrighted by DSM.
Sign Up for Free e-newsletters
Psychiatry Advisor Articles
- #MeToo: Helping Victims Cope With Sexual Harassment
- Association Between Psychosis and Development of Dementia in Older Men
- Phonemic Verbal Advantage in Mild Cognitive Impairment May Predict Risk for Alzheimer Disease
- Psychosis Could Be a Potential Side Effect of Steroid Treatment in Kids
- Guidance Offered for Improving Mental Health in Workplace
- Triiodothyronine in the Treatment of Bipolar Depression
- Nutritional Influences on Bipolar Disorder in Children
- Old Challenges and New Directions in Managing Tardive Dyskinesia
- Early Intervention Strategies for Bipolar Disorder: Clinical Dilemmas and Directions
- Similar Rates of Childhood Trauma in Schizophrenia and Substance Use Disorders
- Psychiatric Comorbidities Increase Neurologic Disability in Multiple Sclerosis
- Self-Regulation Interventions Beneficial for Children
- Traumatic Brain Injury Associated With Increased Risk for Dementia
- Adverse Neurodevelopmental and Mental Health Outcomes in PCOS
- Depression and Sleep Disturbances: Common Bedfellows