Intracranial inflammatory cystic lesion dr ahmed esawy ct mri part 3 • 1-arachnoid cysts • 2-porencephalic cyst, • 4-multicystic encephalomalacia • 3-hydranencephaly • 5-holoprosencephaly • 6-hydrocephalus (aqueduct stenosis) • 7-periventricular leukomalacia (PVL), • 8-septum pellucidum changes CSP CV CI • 9-dandy walker malformation • 10-dandy walker varaint • 11-mega cisterna magna • 12-schizencephaly • 13-conatal cysts • 14-subependymal cysts • 15-encephalomalacia, • 16-subarachnoid cyst • 17-cystic lesions after brain surgery and radiation injury to the brain. • 18-Leptomeningeal cyst • 19-Post traumatic porenencephally • 20-brain abscess • 21-cysticercosis • 22-hydatid cyst. • 23-amoebic abscess • 24-Aneurysm • 25-Parenchymal Perianeurysmal Cystic Changes in the Brain • 26-Vein of Galen malformation • 27-epidermoid cysts • 28-dermoid cyst (cystic teratoma) • 29-craniopharyngioma • 30-cystic astrocytoma • 31-cystic meningioma • 32-cystic shwannoma • 33-hemangioblastoma • 34-cystic metastasis • 35-cystic pituitary adenoma • 36-Cystic degeneration / necrotic neoplasm • 37-colloid cysts • 38-Rathke’s cleft cysts, • 39-neuroepithelial cysts • 40-neuroenteric cysts • 41-pineal cysts. • 42-Choriod plexus cyst • 43-CSF-Iike Choroidal Fissure and Parenchymal Cysts of the Brain • 44-Trigonal cyst • 45-Interhemispheric cyst • 46-Dorsal cyst • 47-Ependymal cysts • 48-Enlarged VRS • 49-Cystic trapped 4th ventricle • 50-Diverticulation of 3rd , lateral ventricle

1. Inflammatory and infectious
intracranial cysts
• 20-brain abscess
• 21-cysticercosis
• 22-hydatid cyst.
• 23-amoebic abscess
Dr Ahmed Esawy

2. Brain Abscess
Dr Ahmed Esawy

3. Brain abscess..
poorly defined area of posterior parietal brain edema (arrows). Early cerebritis
may not outline a focal mass clearly
Dr Ahmed Esawy

4. Brain abscess.
a poorly defined pattern of mass effect and low attenuation in the left temporal lobe.
Of early cerebritis
Dr Ahmed Esawy

5. Brain abscess.
An area of ring like enhancement (yellow arrow) is noted within a much larger pattern of
edema (white arrow). The central core of the abscess (black arrow) does not enhance
(central necrosis) Dr Ahmed Esawy

6. temporal lobe abscess, extracranial, subdural, and intracerebral abscesses
Dr Ahmed Esawy

7. Brain abscess.
depressed skull fracture. The left parietal cranial injury an abscess of the subgaleal
space (SGA) the epidural space (EDA) the left cerebral hemisphere (CA).
Dr Ahmed Esawy

8. Brain abscess. Axial T1 +C ,T2-weighted MRI in a patient with a right frontal abscess.
Dr Ahmed Esawy

9. The right frontal lobe of the
brain is shifted across the
midline (double arrow) by an
intracranial abscess (single
black arrow) that has extended
upward from the medial right
orbit and medial ethmoid air
cells (curved dotted arrow).
T1-contras Brain abscess T1-contras
the enhancement within the right ethmoid
sinuses from which the infection arose.
The medial superior right maxillary sinus
has been destroyed (yellow arrow).
T1-contras
An abscess is noted within the medial inferior right orbit. The right maxillary sinus
(double white arrows) contains infected secretions and mucus
Dr Ahmed Esawy

10. Brain abscess. (FLAIR) MRI
in a patient with abscess of the
cerebellar vermis (black arrow).
T2- MRI abscess of the midline
cerebellum. the large area of
increased signal, both within the
abscess and within the surrounding
cerebellum (black arrow).
Dr Ahmed Esawy

11. Brain abscess. T1-enhanced
central zone of enhancement
within the abscess, with a zone of
decreased brightness (edema,
white arrow).
Brain abscess. T1enhanced
enhanced mass within the right medial
cerebellum (yellow arrow). The thick-
walled cystic mass was opened.
Dr Ahmed Esawy

12. CEREBRAL ABSCESS ON DW MRI
On trace DWI abscesses are typically
hyperintense, indicating decreased diffusion of
water.
– This is secondary to increased viscosity of pus
which contains, in addition to cellular debris and
bacteria, large molecules such as fibrinogen, which
bind water molecules and add to the effect of
restricted diffusion.
– This can be confirmed with an apparent diffusion
coefficient (ADC) map where abscesses are of low
signal ,markedly reduced ADCDr Ahmed Esawy

13. Diffusion-weighted Imaging
ADC maps are of great value in
distinguishing neoplasms in ADC maps is
more often have facilitated diffusion,
Dr Ahmed Esawy

14. CEREBRAL THALAMIC ABSCESS ON MRI
Post-Gd T1WI: WI2T DWI
Dr Ahmed Esawy

15. Left and right frontal abscesses:
35-year-old male.
DWI ADCWI2TWI1T
Dr Ahmed Esawy

16. Pyogenic Abscess
T2 T1 T1/Gd DWI
bright on DWI
Dr Ahmed Esawy

17. Abscess (purulent)
ADC decreased
dark on ADC mapDr Ahmed Esawy

18. 7. 8.
DD : tumour
central hypointensity on diffusion-weighted image and hyperintensity on ADC
map, consistent with the diagnosis of tumor.
Dr Ahmed Esawy

19. 7. 8.
DD : tumour
Central hypointensity is seen on the diffusion-weighted image and hyperintensity
on the ADC map, consistent with the diagnosis of tumor.
Dr Ahmed Esawy

20. Brain abscess primary and secondary (daughter
Fluid and necrotic tissue (bright area) . edema surrounds
the abscess cavities (black arrows).
surrounding the abscess does not enhance
(white arrows).
DWI
T1/Gd
Dr Ahmed Esawy

21. Brain abscess (FLAIR)
left occipital-parietal brain abscess.
Dr Ahmed Esawy

22. MRI Brain
abscess
T1/Gd
T2
well-defined hypointense
capsule
DWI
Dr Ahmed Esawy

23. MR Spectroscopy
• .Typical MR spectroscopic features of brain
abscesses include
• elevated peaks of amino acid, lactate,
alanine, acetate, pyruvate, and succinate
• absent signals of NAA, creatine, and choline.
Dr Ahmed Esawy

24. MR spectroscopy
• shed light on which organism is
responsible for the abscess
• because the presence of anaerobic
bacteria tends to cause elevated acetate
and succinate peaks.
Dr Ahmed Esawy

25. DD : NEOPLASM
• Elevation of choline and absence of
signal from a variety of amino acids,
acetate and succinate favours
neoplastic process
Dr Ahmed Esawy

26. Dr Ahmed Esawy

27. Dr Ahmed Esawy

28. necrotic or cystic neoplasmsPyogenic brain abscesses
Elevated choline , decrease
NAA
elevated peaks of amino acid,
lactate, alanine, acetate,
pyruvate, and succinate
absent signals of NAA,
creatine, and choline
MRS
facilitate diffusion
dark
restricted diffusion
bright
DW
Bright on ADC map
The walls of necrotic or cystic
tumors have a lower ADC
value than of an abscess
markedly reduced ADC maps.ADC
wall of necrotic or cystic
neoplasms tends to have higher
rTBV
capsule of an abscess tends to
have lower rTBV
MR PERFUSION
Dr Ahmed Esawy

29. Signal volume MR spectra of
abscess
Short-echo MRS shows depression of the
NAA, choline (Cho) and creatine (Cr)
as well as elevation of the amino acid,
lactate (Lac), acetate and succinate.Dr Ahmed Esawy

30. T2 T1+C
Single voxel MRS peaks representing
alanine, lactate and amino acids
DW hyperintense
signal in centre
ADC decrease signal
in centre
Brain abscess
Dr Ahmed Esawy

31. brain abscess
Dr Ahmed Esawy

32. Brain abscess in a 28-week gestation
preterm newborn
well-defined cystic structure with low-
level echoes (arrowheads) in the left
posterior parietal region
abscess has ring enhancement
(arrowheads).Dr Ahmed Esawy

33. cysticercosis
Dr Ahmed Esawy

34. Cystercercus cellulosae - (3-20 mm)
regular round thin walled cyst,
produces only mild inflammation
larva in cyst
Dr Ahmed Esawy

35. Calcification in cysticercosis
• Calcification in burned out residues of cysticercosis
scattered throughout the brain in later stagesDr Ahmed Esawy

36. NEUROCYSTICERCOSIS
Multiple neurocysticercosis cysts
of various sizes. Some contain
visible scolices (arrows). MR
image shows
T1 innumerable tiny low-signal-intensity
neurocyticercosis cysts in brain
parenchyma and subarachnoid spaces.
Most contain small “dot” that represents
the scolex (arrows
Dr Ahmed Esawy

37. Intraparenchymal cysticercal cyst
Scolex within each cyst
Dr Ahmed Esawy

38. Differential Diagnosis
• abscess (T2-hypointense rim (
• Tuberculosis (profoundly hypointense on T2 ,meningitis)
• toxoplasmosis
• neoplasm primary or metastatic
• enlarged PVSs same appearance as CSF at all MR
sequences and do not enhance)
• NEUROCYSTICERCOSIS characteristic “cyst with dot”
appearance .
Dr Ahmed Esawy

39. multiloculated
amebic abscess
partially cystic mixed-signal-intensity
subcortical mass (arrow)T1.
some enhancement around complex cystic
mass (arrow)T1+CONTRASTDr Ahmed Esawy

40. Differential Diagnosis
• Complex conglomerated parasitic cysts of
any origin may mimic primary or
metastatic brain tumor .
Dr Ahmed Esawy

41. hydatid cyst
CT Unilocular cyst CSF density No edema no enhancement ± calcification
MRI low signal T1 , high signal T2 Dr Ahmed Esawy

42. hydatid cyst
T1+C
T1
T2
Dr Ahmed Esawy

43. HYDATID CYSTS
• 5 year child
very large nonenhancing cystic mass
without surrounding edema (arrows). Dr Ahmed Esawy

44. Differential Diagnosis
• arachnoid cyst
• epidermoid cyst
• neurocysticercosis
Dr Ahmed Esawy

45. Tuberculous abscesses
T1- multiple scattered ring-enhancing lesions
Dr Ahmed Esawy

46. MRS
• Tuberculous abscesses typically have high
lipid and lactate peaks.
• These abscesses have no peaks for amino
acids (leucine, isoleucine, and valine) at 0.9
ppm, succinate at 2.41 ppm, acetate at 1.92
ppm, and alanine at 1.48 ppm,
• in contrast to pyogenic abscesses, which
have peaks for all these metabolites.
Dr Ahmed Esawy