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: None
Deep gray nuclei:
Region 1: Age-indeterminate though chronic appearing left capsular lacunar infarct.
Region 2: Very subtle hypodensity in the right caudate head inferiorly and caudate body (coronal, axial).
Hyperdense vessels: None

Case Discussion:
1. An age-indeterminate though chronic appearing left capsular lacunar infarct should be apparent on the axial images. The degree of hypoattenuation suggests chronic insult, though MRI or prior imaging would be better for accurate aging of this hypodensity.
2. Upon retrospective review, there is an additional very subtle additional faint hypodensity in the right caudate head, suspicious for an acute infarct.  Note the asymmetry on the axial images. Deep gray nuclei infarcts are best detected and characterized with MRI, though can be suspected or identified on nonenhanced CT examinations within methodical approach.

Review of Basal Ganglia Anatomy
The term "basal ganglia" encompasses several gray matter structures, including the caudate, putamen, globus pallidus, subthalamic nucleus, and substantia nigra. The subthalamic nuclei and substantia nigra are located in the brainstem and not well visualized directly on CT imaging; brainstem pathology is often difficult to discern on CT given beam hardening artifact from the temporal bones. Of note, the thalami are not part of the basal ganglia, though are additional deep gray structures.

As additional vocabulary, "striatum" refers to the caudate and putamen. And "lentiform nuclei" refers just to the globus pallidus and putamen. The caudate extends along the lateral margin of the lateral ventricle, and has a head (anteriorly), body (superiorly, coronal), and tail (inferiorly).

The internal capsule and external capsule contain white matter tracts which help delineate the margins of the deep gray nuclei, and can be seen on CT examination. With the internal capsule, there is the anterior limb, genu, and posterior limb of the internal capsule. There is also an external capsule lateral to the putamen.

For brevity when discussing both deep gray nuclei and white matter capsules, gangliocapsular, lenticulocapsular, and retrolenticular terms are used for describing overlapping pathology in these regions.
Hopefully this reinforcement of the deep gray nuclei and capsular terminology will assist with detecting subtle abnormalities in these regions. Although MRI is the best modality for detecting acute infarcts within the deep gray nuclei, CT remains critical in the initial cerebrovascular accident workup for excluding a large vascular territory infarct, acute intracranial hemorrhage, or critical mass effect.

Imaging follow up CT examination (Scan 2)
Subsequently CT imaging demonstrated increased hypoattenuation of the right caudate head and caudate body (axial image). No acute hemorrhage.
Primary teaching points:

1. Review imaging findings of subtle and very subtle deep grey nuclei infarcts.
2. Review deep gray nuclei anatomy and common terminology.
3. Review white matter capsule anatomy and terminology.


Non-Contrast CT

Which of the following is not part of the basal ganglia?