Imaging Artifact vs. Acute Cerebellar Infarct
This low-signal focus on the inferior surface of the right cerebellar hemisphere is most likely a technical artifact and does not represent an acute cerebellar infarct, given the absence of restricted diffusion elsewhere and the radiologist's notation that it may be an artifact of the lowest slice.
Diagnostic Reasoning
The key discriminating features here strongly favor artifact over true infarction:
No restricted diffusion on DWI/ADC sequences elsewhere - This is the critical finding. Acute cerebellar infarction would show bright signal on DWI with corresponding dark signal on ADC maps 11. The absence of this pattern throughout the rest of the cerebellum and brain argues against acute ischemia.
Location at the lowest imaging slice - Artifacts commonly occur at the edges of imaging volumes due to partial volume effects, susceptibility artifacts from the skull base, or motion. The radiologist's explicit mention of this being "the lowest slice" is a red flag for technical artifact.
Isolated finding without supporting evidence - True cerebellar infarction, even small ones, typically show additional imaging correlates or clinical symptoms 23.
Clinical Context Matters
Initial CT can be normal in up to 25% of cerebellar infarction patients 1, but MRI with DWI is highly sensitive for acute ischemia. The fact that DWI shows no other abnormal diffusion is reassuring.
Cerebellar infarcts typically present with:
- Rotatory dizziness intensified by motion
- Nausea and vomiting
- Imbalance and gait ataxia
- Nystagmus
- Truncal ataxia (commonly missed on bedside exam) 12
Recommended Management
If the patient is clinically asymptomatic or symptoms don't match cerebellar localization:
- No acute intervention required - Treat this as artifact
- Document the finding and clinical correlation in the medical record
- Proceed with standard stroke risk factor management if this was part of a stroke workup
If there is ANY clinical suspicion for cerebellar stroke (vertigo, ataxia, nausea):
- Repeat MRI with dedicated posterior fossa sequences to definitively exclude cerebellar infarction 34
- Consider thin-slice DWI through the posterior fossa to eliminate partial volume effects
- Clinical vigilance is essential because cerebellar infarcts can initially appear clinically indolent but deteriorate into life-threatening complications with brainstem compression and hydrocephalus 14
Critical Pitfall to Avoid
The most dangerous error is dismissing true cerebellar infarction as a "benign labyrinthine disorder" 2. However, in this case, the imaging characteristics (isolated finding at slice edge, no diffusion restriction) combined with the radiologist's assessment make artifact the most likely diagnosis. The absence of restricted diffusion elsewhere is your safety net - acute ischemia would show up on DWI.
If clinical symptoms emerge (particularly decreased level of consciousness, which signals swelling and brainstem compression 1), immediate neurosurgical consultation and repeat imaging are mandatory, as peak swelling occurs several days after ischemia onset 1.