Tag Archives: radiology

MRI evolution of Cerebral Abscess

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Reference:

Criner, G., Barnette, R. and D’Alonzo, G. (2010). Critical Care Study Guide. Dordrecht: Springer.

 

 

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Mt. Fuji Sign

The Mt. Fuji sign is a radiologic finding seen in tension pneumocephalus.  Bilateral hypoattenuating collections are seen in the frontal subdural space, which causes compression and separation of the frontal lobes.

 

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Notice the widening of the interhemispheric space between the tips of the frontal lobes which resembles the silhouette of Mt. Fuji.  

 

In tension pneumocephalus, air enters into the cranial vault through disruption of the skull or skull base.  Air pressure increases within the subdural space due to a ball-valve mechanism, where air enters into subdural space but egress of air is blocked by an obstruction.

Tension pneumocephalus may occur after surgical evacuation of SDH (2.5-16%), skull base surgery, paranasal sinus surgery, posterior fossa surgery in sitting position, or head trauma.

To diagnose tension pneumocehpalus, CT findings should correlate with clinical signs of deterioration.

Peaking sign” (compression of frontal lobes without separation of frontal lobes) has also been linked to tension pneumocephalus.

Treatment includes:

  1. emergent decompression to alleviate pressure
    1. drilling burr holes
    2. craniotomy
    3. needle aspiration
    4. EVD placement
  2. administration of 100% oxygen
  3. closure of dural defects
  4. careful monitoring for clinical signs of deterioration
  5. serial CT scanning of brain

This is Mt. Fuji in Japan

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Reference

Michel, Steven J. “The Mount Fuji Sign.” Radiology 232.2 (2004): 449-450.

 

Choroid Plexus Blood Supply

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Reference:

Haines, Duane E. Neuroanatomy : An Atlas Of Structures, Sections, And Systems. 8e, 2012.

Digital Map of PCA Infarcts

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Reference:

Phan, MBBS, FRACP, T. G. et al. “Digital Map Of Posterior Cerebral Artery Infarcts Associated With Posterior Cerebral Artery Trunk And Branch Occlusion”. Stroke 38.6 (2007): 1805-1811.

Digital atlas of MCA territory infarction

The color refers to the frequency of infarction at each voxel. The highest frequency of infarct occurrence is in the centrum semiovale and striatocapsular and insular regions.

 

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Reference:

Phan, T. G. et al. “A Digital Map Of Middle Cerebral Artery Infarcts Associated With Middle Cerebral Artery Trunk And Branch Occlusion”. Stroke 36.5 (2005): 986-991.

Hydrocephalus CT Findings

KEY FINDINGS of HCP on neuroimaging:

  • expansion of the temporal horns
  • convexity of the third ventricular walls
  • rounding of the frontal horns
  • effacement of sulci
  • enlargement of ventricles out of proportion to sulcal dilatation

 

Reference:

Dupont, Stefan and Alejandro A Rabinstein. “CT Evaluation Of Lateral Ventricular Dilatation After Subarachnoid Hemorrhage: Baseline Bicaudate Index Balues”. Neurological Research 35.2 (2013): 103-106.

Patterns of Contrast Enhancement in Brain CT/MRI

7 Patterns of Contrast Enhancement seen in CT / MRI of the Brain:

  • Dural-based enhancement (meningioma)
  • Dura-arachnoid enhancement / pachymeningeal enhancement.
  • Pia-arachnoid or subarachnoid enhancement (bacterial meningitis or carcinomatous meningitis)
  • Gyral gray matter enhancement
  • Ring lesions – A. smooth ring (abscess)  B.  irregular ring, shaggy inner margin (necrosis, high-grade neoplasm)
  • Fluid-secreting neoplasms and demyelination
    • cerebellar “cyst with nodule” (pilocytic astrocytoma)
    • classic “open-ring” sign (tumefactive demyelinating lesions)
    • fluid secreting “cyst with nodule”
  • Periventricular enhancement
    • thin linear rim of enhancement – ependymitis (CMV infection)
    • mass / thick irregular rind surrounding ventricle (periventricular lymphoma, primary B cell lymphoma)

 

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  1.  Dura-arachnoid enhancement / pachymeningeal enhancement.

2. Dural-based enhancement   (typical for meningioma)

3. pia-arachnoid or subarachnoid enhancement (bacterial meningitis or carcinomatous meningitis)
4.  gyral gray matter enhancement
5.  ring lesions – A. smooth ring (abscess)  B.  irregular ring, shaggy inner margin (necrosis, high-grade neoplasm)
6.  Fluid-secreting neoplasms and demyelination
a. cerebellar “cyst with nodule” (pilocytic astrocytoma)
b. classic “open-ring” sign (tumefactive demyelinating lesions)
c.  fluid secreting “cyst with nodule”
7.  periventricular enhancement
a.  thin linear rim of enhancement – ependymitis (CMV infection)
b.  mass / thick irregular rind surrounding ventricle (periventricular lymphoma, primary B cell lymphoma)

 

 

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Reference:

Naidich, Thomas P et al. Imaging Of The Brain. Ch 5 Patterns of Contrast Enhancement.  1st ed. Print. pp. 79-95.