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

Case Findings (Scan 1)
Hemorrhage: No
Hydrocephalus: No
Herniation: No
Gray-white differentiation/wedge-shaped hypodensity/cortical involvement: Yes.
Subtle blurring of the gray-white matter differentiation in the right subinsular region and focal hypodensities in the right frontal corona radiata, suspicious for acute infarct.
Deep gray nuclei: Hypodensities in the right striatum (putamen and globus pallidus and caudate body). Additional dark hypodensity in/near the left caudate body, likely a chronic lacunar infarct.
Hyperdense vessels: Hyperdense right supraclinoid internal carotid artery and middle cerebral artery proximal M1 segment.


Case Discussion:
1. Initial review of the axial head CT imaging on stroke windows should reveal subtle hypodensities in the right corona radiata, blurring of the right subinsular white matter, and hypodensities in the right striatum. Upon assessment for hyperdense vessels, the terminal right internal carotid artery and proximal right middle cerebral artery M1 segment appears denser than the contralateral side. Constellation of findings is most concerning for a terminal right internal carotid artery occlusion and acute right middle cerebral artery vascular territory infarct. Prompt communication of these findings is essential, especially if the patient is a candidate for mechanical thrombectomy. Depending on the practice environment, mechanical thrombectomy candidacy may be considered to the level of the sylvian fissure and proximal middle cerebral artery M2 branches.

Hemorrhagic transformation
Hemorrhagic transformation is fairly nonspecific for guiding treatment decisions as the term includes both smaller petechial and larger parenchymal hemorrhages. Based on the European-Australasian Acute Stroke Study (ECASS II), characterizing the hemorrhage as:
a) petechial or parenchymal
b) no mass effect or with mass effect
c) within less than 30% or greater than 30% of the infarct
may be of greater clinical utility.

Given heterogeneity of practice patterns, a description of the degree of hemorrhage containing these components is usually sufficient to assist with guiding treatment decisions.

Hydrocephalus
Assessing for hydrocephalus should be performed on every head CT examination, with search patterns best utilizing a functional approach following the theorized flow of cerebrospinal fluid: Components of the lateral ventricles include the frontal horn, body, atrium, occipital horn, and temporal horn. Lateral ventricle CSF flows through the foramen of Monroe into the third ventricle, and then into the cerebral aqueduct to reach the fourth ventricle, and finally extending through the foramen of Magendie (midline) and foramen of Luschka (lateral). This functional search pattern allows assessment for lesions obstructing CSF flow, and careful scrutiny of the third ventricular caliber and temporal horns of the lateral ventricles often assists with detecting early hydrocephalus with prior exams.

After assessing CSF flow emanating to the foramen of Luschka, the premedullary and prepontine subarachnoid spaces should be contiguous with the suprasellar and perimesencephalic cisterns. As a brief rapid review, note the suprasellar cistern and sylvian cistern. Then check the perimesencephalic cisterns: interpeduncular cistern, crural cistern, ambient cistern, and quadrigeminal cistern.

Uncal Herniation
Scrutiny of the suprasellar cisterns is essential for detecting herniations particularly on the axial view, in particular with CT 2 demonstrating slight medialization of the right uncus, and CT 3 demonstrating right uncal herniation with increased uncal medialization. Of note, uncal herniations are perhaps best characterized on the coronal view upon seeing the uncus "peak" over the underlying tentorium on CT 3 compared to CT 1.

Imaging follow up CT examination at 24 hours (Scan 2)
Subsequent head CT "02" performed 24 hours later demonstrates evolution of the extensive infarct right middle cerebral artery vascular territory infarct with marked hypodensity and minimal scattered regions of petechial hemorrhages within the infarct and involvement of the basal ganglia and thalamus. No mass occupying hematoma identified. Mass effect and edema effaces the majority of the right cerebral hemisphere sulci and contributes to a local right-to-left midline shift of approximately 3 mm. The right lateral ventricle is effaced, though the temporal horn is nondilated. Slight medialization of the right uncus (coronal).

Imaging follow up CT examination several days later (Scan 3)
Subsequent head CT "03" performed several days later demonstrates extensive hemorrhagic conversion of the large right MCA vascular territory infarct with hyperdense parenchymal hemorrhage throughout the majority of the infarct. There is 10 mm right to left midline shift, increased right lateral ventricle effacement, dilation of the temporal horn of the right lateral ventricle suggesting temporal horn trapping, and right uncal herniation (coronal).
Primary teaching points:

1. Proximal large vessel arterial occlusions may be a candidate for mechanical thrombectomy. Early recognition of this pathology is critical for improved outcomes.
2. Considerations for describing "hemorrhagic transformations" using ECASS II metrics to maximize clinical utility for treating clinicians.
3. Anatomical review of theorized ventricular cerebrospinal fluid flow to assist a functional search pattern.
4. Uncal herniation on the coronal images.


Non-Contrast CT

Which view is best for assessing for uncal herniation?