15 Questions
Based on the information provided, what did the interpreting radiologist conclude about the initial non-contrast CT head?
There is a suspicious CT abnormality to correlate with the patient's symptoms.
Which imaging modality is the most sensitive for evaluating an acute brain infarct?
MRI brain without contrast
According to the information provided, which of the following is a characteristic CT finding of an acute cerebral infarct?
Hyperdense (bright) vessel sign
Which of the following is a characteristic MRI finding of an acute cerebral infarct?
Hyperintense on DWI
What is the appropriate next step in imaging for this patient, based on the information provided?
Proceed directly to MRI brain without contrast
Which of the following is a common limitation of non-contrast CT in the evaluation of acute cerebral infarction?
May not show evidence of acute infarct in the first few hours
Which of the following statements accurately compares CT and MRI?
Patient cooperation is more important for MRI than for CT scans.
Which of the following organizations publishes appropriateness criteria for clinical imaging exams?
American College of Radiology
Which of the following factors should be considered when selecting between CT and MRI for imaging?
All of the above
Which imaging modality is generally preferred for patients with pacemakers or aneurysm clips?
CT
What is a key advantage of MRI over CT in terms of patient safety?
MRI does not involve ionizing radiation exposure.
Which type of Le Fort fracture is characterized by involvement of the zygomatic arch?
Le Fort III
Which of the following is NOT a typical indication for using IV gadolinium contrast in MRI neuroimaging?
Evaluating stroke, trauma, or degenerative spine disease
Which neuroimaging modality is typically performed without contrast for evaluating the head and neck vasculature?
MRA of the head
When would a CT of the head and neck soft tissues typically be performed with contrast?
Both a and b
Study Notes
Acute Cerebral Infarct
- 61-year-old female presents with acute onset right-sided weakness and aphasia, history of atrial fibrillation, hypertension, COPD, and discontinued anticoagulation due to frequent falls
- Interpreting radiologist concludes that there is evidence of a right-sided infarct
Imaging Modalities for Acute Brain Infarct
- Most sensitive imaging modality: MRI brain without contrast (hyperintense on DWI)
- CT head: may not show acute infarct, especially in the first few hours; signs include hypodense areas, loss of gray/white differentiation, and swelling/edema
- MRI: hyperintense on DWI, hypointense on T1, and hyperintense on T2/FLAIR; signs include loss of gray/white differentiation and sulcal effacement
CT vs MRI
- CT: cheaper, faster, uses ionizing radiation, and has lower patient cooperation requirements
- MRI: more expensive, takes longer, does not use ionizing radiation, and requires higher patient cooperation
ACR Appropriateness Criteria
- Published by the American College of Radiology (ACR)
- Extremely helpful for determining appropriateness of clinical imaging exams
Neuroimaging Exams
- CT Neuroimaging exams: usually performed without contrast, except for CTs of head and neck soft tissues, CT angiograms, and CT venograms
- MR Neuroimaging exams: IV gadolinium contrast indicated for infection, primary tumors or metastatic disease, demyelinating disease, and a few others; not usually necessary for stroke, trauma, or degenerative spine disease
Learn about the differences between CT and MRI scans, including cost, safety, acquisition time, patient cooperation, and use of contrast material. Understand the appropriateness criteria for choosing between CT and MRI in medical imaging.
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