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.
Region 1: Cortical hypoattenuation and loss of gray-white matter differentiation in the left parietal region, suspicious for acute infarct.
Region 2: Focal wedge-shaped hypodensity in the right superior cerebellar hemisphere, age-indeterminate though likely chronic.
Deep gray nuclei: Preserved
Hyperdense vessels: None

Case Discussion:
1. Upon slice-by-slice review of the axial CT imaging on stroke window, a relative absence of normal cortical density in the left parietal region should raise suspicion for an acute infarct. Frontoparietal infarcts are sometimes better visualized on the sagittal reformats. The infarct best corresponds with the left middle cerebral artery distal M2 inferior division vascular territory.
2. An additional focal wedge-shaped hypodensity in the right superior cerebellar hemisphere could reflect an additional age-indeterminate infarct, though is likely chronic given the degree of hypoattenuation. Coronal reformats and be helpful in assessing the cerebellar and occipital regions.

Anatomy review of the gyral anatomy
Delineating the margins between the frontal and parietal lobes can sometimes pose a challenge for radiologist, though anatomic localization of clinical symptoms can be a useful adjunct when assessing for subtle stroke. A brief review of common anatomical landmarks useful for delineating the precentral gyrus (frontal lobe, motor function), central sulcus, and postcentral gyrus (parietal lobe, sensory function) include:
a) Superior frontal sulcus: Anatomic junction between the superior frontal gyrus and middle frontal gyrus.
b) Precentral gyrus: Posterior portion of the frontal lobe. Provides motor function and is the origin of the cortical spinal tract. An inverted "omega" symbol often corresponds to the hand motor region. This patient likely has right-sided hand weakness.
c) Central sulcus: Anatomically marked between the precentral and postcentral gyrus. Paracentral lobule is noted medially and is a continuation of the pre- and post- central gyrus.
d) Postcentral gyrus: Anterior portion of the parietal lobe. Provide sensory function. The postcentral gyrus is often thinner in caliber compared to the precentral gyrus.
e) Intraparietal sulcus: Anterior margin of the intraparietal sulcus sometimes and at the postcentral gyrus.
f) Marginal sulcus: Also known as the pars marginalis. Often positioned posterior to the paracentral lobule.

The presence of a few of these anatomic landmarks for determining the location of the frontal parietal regions is helpful for functional anatomic localization. Pathology such as a large brain mass can distort the frontoparietal anatomy, and knowing additional anatomic landmarks for accurate localization may be of clinical utility.

Imaging follow up MRI (Scan 2)
Subsequent MRI imaging demonstrates an acute left frontoparietal infarct (high DWI signal, low ADC signal) with involvement of the left precentral gyrus, and likely corresponding to symptoms of right-sided weakness. Additional small chronic right cerebellar infarct (absence of the DWI signal, presence of volume loss). 

Primary teaching points:
1. Review orthogonal reconstructions useful for detecting subtle cortical infarcts.
2. Review chronic appearing small cerebellar infarcts.
3. Review functional anatomy of the precentral and postcentral gyrus.
4. Review anatomic landmarks for delineating the frontal and parietal lobes.


Non-Contrast CT