1. PATTERNS OF EDEMA James G. Smirniotopoulos, M.D.
Professor of Radiology and Neurology
Chairman, Department of Radiology and Nuclear Medicine
Uniformed Services University of the Health Sciences
4301 Jones Bridge Road
Bethesda, MD USA
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2. DISCLAIMER:
The opinions expressed herein are those of the author(s), and are not necessarily representative of the Uniformed Services University of the Health Sciences (USUHS), the Department of Defense (DOD); or the World Health Organization (WHO). Medicine is a constantly changing field, and medical information is subject to frequent correction and revision. Therefore the reader is entirely responsible for verifying the accuracy and relevance of the information contained herein. Portions herein copyright 2000 James G. Smirniotopoulos, M.D.

3. EDEMA Definitions - Cytotoxic Fluid ‑ Ecf) - Vasogenic
Increase In Tissue Water
Intracellular
- Cytotoxic
Extracellular (Interstitial, Extra Cellular
Fluid ‑ Ecf)
- Vasogenic
- Hydrostatic (Hydrocephalic)

4. EDEMA: -Decreased Attenuation T1W ‑ Decreased Signal Intensity
INCREASED TISSUE WATER
CT: Decreased SPECIFIC GRAVITY
-Decreased Attenuation
MR: Prolongs BOTH T1/T2
T1W ‑ Decreased Signal Intensity
T2W ‑ Bright

5. EDEMA: PD ‑ INCREASED SIGNAL usually > CSF except Macrocystic
Encephalomalacia
T2W ‑ INCREASED SIGNAL (Often <>CSF, depends on the windows and pulse sequence)

6. Interstitial Edema (Ions, Small Proteins) - Abscess - Neoplasm
Abnl. Or Absent Bbb
Plasma Ultrafiltrate
(Ions, Small Proteins)
Spreads From Neovascularity
- Abscess
- Neoplasm
Localized In Infarct
- No "Pump"

7. Figure

8. WHITE MATTER (Accepts Interstitial Edema) Relatively Loose
Organized Tracts
(Natural Conduits For Edema)
Larger ECF
More Compliant
(To Increased Size Of ECF)
Spreads Until Production =
Absorption (Over Large Area)

9. GRAY MATTER (Resistant To Interstitial Edema): More Dense And Compact
Small ECF
(Almost Non‑Existent)
Non‑Compliant
(To Increased Size Of ECF)

10. CYTOTOXIC EDEMA Metabolic/Ischemic Metabolic Poisons:
Energy Dependent Pump
Metabolic Poisons:
- Cn, Triethyl Tin, Hexachlorophene.
Passive Exchange Across Cell Membrane
Intracellular Edema
Cortical Gray Matter

11. Figure

12. ISCHEMIC EDEMA (From Ischemic Insult): Cytotoxic Vasogenic
Both Gray And White
Vasogenic
White Matter Only
Limited By Low Perfusion

13. EDEMA LOCATIONS Edema Patterns White Matter Only:
- Peritumoral (Peri‑Lesional)
- Periventricular (Hydroceph.)
Gray And White Matter
- Vascular Territory (If Infarct)
- Gray regional if encephalitis

14. EDEMA RIVERS (Spreads Readily): EXTERNAL CAPSULE EXTREME CAPSULE
UNCINATE FASCICULUS
"U" FIBERS
Centrum Semiovale
Other Association fiber tracts

15. EDEMA DAMS (Effectively Block Spread): - Both Deep And Cortex
INTERNAL CAPSULE (Projection)
CORPUS CALLOSUM (Commissure)
GRAY MATTER
- Both Deep And Cortex

16. EDEMA LOCATION White Only White And Gray (Also Gray Only)
Peri‑Tumoral (Peri‑Lesional)
Periventricular
White And Gray (Also Gray Only)
Vascular Territory

17. PATTERNS OF EDEMA Hydrocephalic (Hydrostatic) Edema
Extracellular (Interstitial) Edema
Distention of Ventricle
Ependymal lining rips open
CSF pours into brain parenchyma
Edema spreads from ventricle through white matter
Chronic edema => demyelination

18. EDEMA ETIOLOGY Neoplasm/Abscess Hydrocephalus Ischemia
Vasogenic (White Only)
Hydrocephalus
Hydrostatic (White Only)
Ischemia
Cytotoxic (Gray And White)
(Also Gray - Only esp. Encephalitis)
Limited Vasogenic

19. Bibliography EXTREME CAPSULE UNCINATE FASCICULUS "U" FIBERS
Bartkowski HM. Peritumoral Edema. Prog exp Tumor Res 1984;
Bradac GB, Ferszt R, Bender A, Schorner. Peritumoral edema in meningiomas. A Radiological and Histological Study. Neuroradiology 28 (1986): ;
Bradac G, Ferszt R, Bender A, Schorner W. Peritumoral edema in meningiomas; a radiological and histological study. Neuroradiology 1986;28:
Cooper PR. Delayed Brain Injury: Secondary Insults. Central Nervous System Trauma Status Report 1985;Chap. 13: Ed. B.
Cowley A. Influence of fiber tracts on the CT appearance of cerebral edema: Anatomic-pathologic correlation. AJNR Am J Neuroradiol 1983;4:
Drayer BP and Rosenbaum AE. Brain Edema Defined by Cranial Computed Tomography. J Comp Assist Tomogr 1979;3(3):
Finizio FS. CT and MRI aspects of supratentorial hemispheric tumors of childhood and adolescence. Childs Nerv Syst 1995;
Fishman RA. Brain Edema. NEJM 1975;
Gazendem J, Go KG, van Zanten AK. Composition of isolated edema fluid in cold-induced brain edema. J Neurosurg 1979;51:70-7.
Kamada K, Houkin K, Hida K, Iwasaki Y, Abe H. Serial changes in metabolism and histology in the cold-injury trauma rat brain model--proton magnetic resonance imaging and spectroscopy study. Neurol Med Chir (Tokyo) 1995;35:1-7.
Kimelberg HK. Astrocytic edema in CNS trauma. J Neurotrauma 1992;9 Suppl 1:S71-81.
Kirkwood JR. Essentials of Neuroimaging. New York, Edinburgh, London, Melbourne: Churchill Livingstone; 1990;
Milhorat TH. Classification of the cerebral edemas with reference to hydrocephalus and pseudotumor cerebri. Childs Nerv Syst 1992;8(6):301-6.
Monajati A, Heggeness L. Patterns of edema in tumors vs. infarcts: Visualization of white matter pathways. AJNR Am J Neuroradiol 1982;3:251-5.
O'Brien MD. Ischemic Cerebral Edema. A Review. Stroke 1979;10(6):623-7.
Shapira Y, Artru AA, Qassam N, Navot N, Vald U. Brain edema and neurologic status with rapid infusion of 0.9% saline or 5% dextrose after head trauma. J Neurosurg Anesthesiol 1995;7:17-25.
EXTREME CAPSULE
UNCINATE FASCICULUS
"U" FIBERS