Case Challenge

Brain

Vascular

Daniel Cornfeld

Gain confidence interpreting Subtle Strokes Cases on CT and MRI with MRI Online. Quiz yourself using real-world, interactive scrollable cases &amp; earn CME. Try it free!

Case Review

Neuroradiology

Vascular Imaging

Case 1 - 60-year-old with double vision and dizziness.

Case 2 - 65-year-old with altered mental status.

Case 3 - 65-year-old. Altered mental status.

Case 4 - 68-year-old. Dysphagia and aphasia.

Case 5 - 82-year-old with right hemiparesis.

Case 6 - 70-year-old with confusion.

Case 7 - 60-year-old with right sided weakness.

Case 8 - 70-year-old with right-sided weakness.

Case 9 - 68-year old with aphasia.

Case 10 - 50-year-old with right-sided weakness.

Case 11 - 65-year-old with right visual field defects.

Case 12 - 65-year-old with right-sided weakness.

Case 13 - 60-year-old with left-sided weakness.

Case 14 - 60-year-old with left-sided stroke symptoms.

Case 15 - 60-year-old with bilateral weakness.

Case 16 - 50-year-old with right-sided weakness.

Case 17 - 65-year-old with right-sided weakness.

Case 18 - 60-year-old with altered mental status.

Case 19 - 55-year-old with aphasia.

Case 20 - 60-year-old with left-sided weakness.

Case 21 - 60-year-old with left hemiparesis.

Case 22 - 60-year-old with left visual field defects.

Case 23 - 68-year-old with weakness.

Case 24 - 60-year-old with bilateral weakness.

Case 25 - 90-year-old with acute left hemiplegia.

Subtle Stroke Case Challenge

Course Evaluation

Post-Course Activities

Learn to master subtle stroke cases on CT and MRI! Gain experience detecting strokes on CT by reviewing the 25 cases of subtle strokes presented in this module. The purpose is not to comprehensively explain the role of imaging in the evaluation of acute stroke or to teach a junior physician how to approach a CT scan of the brain. Instead, by reviewing these difficult cases, the reader will become better at detecting the subtle CT findings of acute stroke. Some of these cases were initially interpreted correctly. Many were not.

Subtle Strokes Case Challenge

Major head CT interpretation goals when suspecting stroke
These tips will only preface this first case. Subsequent cases will dive right into the findings.
1. Evaluation for hemorrhage, hydrocephalus, herniation
Generally, a ‘subdural’ window and a ‘brain’ window are sufficient. Consider using an additional 'darker' window if high suspicion for subarachnoid hemorrhages.
2. Evidence of ischemia: blurring or loss of gray-white matter differentiation, wedge-shaped parenchymal hypodensity, cortical involvement/effacement, decreased conspicuity of deep gray nuclei, and hyperdense vessels.
Using a ‘stroke’ window to accentuate the cortex and subcortical white matter is essential. Every case will require fine tuning to obtain the perfect ‘stroke’ window. The best window is the setting that best highlights pathology on your screen. One method is to select the 'default stroke' window, then finely adjust the window to have the brain cortex appear as dense as calvarium, the white matter to be slightly darker, and having a sharp interface between the cortex and underlying white matter.
‘Brain‘ window is a helpful adjunct to stroke windows, particularly with deep gray nuclei and hyperdense vessel assessment. However, fine adjustment of the window on each case may be necessary to accentuate the deep gray nuclei from the adjacent white matter. Again, specific window/level values are less important as every case will require fine-tuning.
In summary, consider reviewing axial and preferred reformats with acute blood, subdural blood, brain, finely tuned stroke, and finely tuned grey nuclei windows.

Case Findings (Scan 1):
Hemorrhage: None
Hydrocephalus: None
Herniation: None
Gray-white differentiation/wedge-shaped hypodensity/cortical involvement: Yes.
Wedge-shaped superior left cerebellar hyperdensity (Axial / Coronal)
Deep gray nuclei: Preserved
Hyperdense vessels: None

Case Discussion:
1. Don’t forget to look at the cerebellum. Clinicians often won't suspect a posterior circulation infarct but you should look for one anyway.
2. Slow scrutiny of axial stroke windows essential. When assessing the gray-white matter and parenchyma, stroke window and 1-2 seconds per slice can be helpful for seeing subtle abnormalities. Cerebellar infarcts can often be seen using these windows.
3. Slow scrutiny of coronal reformats can also be particularly helpful for cerebellar and occipital region assessment. In this case I think the finely tuned grey nuclei windows show the stroke the best but find it on the other windows as well.
4. After focused review of step 1 and 2 and possibly communicating pertinent findings with your clinical colleagues, a thorough review of the exam should be performed.
In this case, an incidental 18 mm deep left parotid gland lesion is partially visualized, and there is likely a right parotid gland superficial/deep junctional lesion as well. A contrast enhanced neck MRI/CT and/or otolaryngology consultation may be appropriate.

Imaging follow up (Scan 2):
Subsequent CT imaging 24 hours later demonstrates increased hypodensity in the left superior cerebellar artery distribution consistent with evolving infarct. Compare the conspicuity to the original scan at the same windows. No acute hemorrhage.

Primary teaching points:
1. Emphasis on stroke windowing, systematic review of cases, slowly assessing each slice.
2. Review incidentals after communicating urgent findings


Non-Contrast CT