MRI MRI Anatomy and Pathology 1 — Questions and Answers
Question 1: On MRI, cortical bone appears as which signal intensity on both T1 and T2 weighted images?
- High signal
- Intermediate signal
- Low signal (signal void) (Correct answer)
- Variable signal
Correct answer: Low signal (signal void)
Cortical bone has very few mobile protons and produces a signal void (low signal) on both T1 and T2 weighted MRI sequences.
Question 2: Which structure in the knee joint is best evaluated with MRI and appears as a low-signal-intensity triangular structure?
- Articular cartilage
- Medial meniscus (Correct answer)
- Anterior cruciate ligament
- Patellar tendon
Correct answer: Medial meniscus
The medial meniscus is best visualized on MRI as a low-signal-intensity fibrocartilaginous triangular structure on coronal and sagittal images.
Question 3: A T1 hyperintense (bright) lesion in the brain is most consistent with which finding?
- Acute infarct
- Pure fluid-filled cyst
- Subacute blood or fat-containing lesion (Correct answer)
- Vasogenic edema
Correct answer: Subacute blood or fat-containing lesion
T1 hyperintensity in the brain is classically associated with subacute hemorrhage (methemoglobin), fat, protein-rich fluid, or melanin.
Question 4: The normal intervertebral disc nucleus pulposus appears as which signal on T2-weighted MRI in a healthy young adult?
- Low signal
- Intermediate signal
- High signal (bright) (Correct answer)
- Signal void
Correct answer: High signal (bright)
The healthy nucleus pulposus is rich in water-containing proteoglycans and appears bright (high signal) on T2-weighted sequences.
Question 5: On diffusion-weighted MRI (DWI), an acute ischemic infarct typically shows:
- Low signal on DWI and high ADC values
- High signal on DWI and low ADC values (Correct answer)
- High signal on DWI and high ADC values
- Low signal on both DWI and ADC maps
Correct answer: High signal on DWI and low ADC values
Cytotoxic edema in acute infarction restricts water diffusion, producing high signal on DWI and low apparent diffusion coefficient (ADC) values.
Question 6: Which MRI sequence is most sensitive for detecting early bone marrow edema in stress fractures?
- T1-weighted SE
- GRE in-phase
- STIR or fat-saturated T2 (Correct answer)
- Proton density without fat saturation
Correct answer: STIR or fat-saturated T2
STIR and fat-saturated T2 sequences suppress the bright fat signal of normal marrow, making the high-signal edema of stress fractures conspicuous.
MRI MRI Anatomy and Pathology 1
On MRI, cortical bone appears as which signal intensity on both T1 and T2 weighted images?