IMAGING CONTRIBUTION IN ARACHNOID INTRACRANIAL

CYST

E.GAMY-J.MAHLAOUI-T.AMIL-S-CHAOUIR-A.HANINE-M.MAHI-S.AKJOUJ

Medical imaging military hospital Mohammed V instruction –Rabat.

NR3

INTRODUCTION

Intracranial arachnoid cysts are defined as a pocket full

of intra-subarachnoid CSF without communication

with the ventricular system.

The aim of this study is to clarify the contribution of

computed tomography (CT) and especially MRI.

In the diagnosis with emphasis on information brought

by the sequences (diffusion) in the differential

diagnosis.

MATERIALS AND METHODS

CT scans performed in axial and coronal.

MRI includes the following morphological sequences

weighted in T1, T2, FLAIR, and T2 * sequences

RELEASE in the different planes.

RESULTS

CT shows a process of expansive cystic lesion that is

hypodense and the same signal as cerebrospinal fluid

(CSF), which can result in thinning of the cortex next,

there is no contrast enhancement.

MRI it has a signal identical to that of (LCS) on the

sequences T1 and T2 without contrast. However to make

a difference with an epidermoid cyst, FLAIR-weighted

sequences, distribution and CISS are a great

contribution.

CT: CSF density bone remodeling, no contrast enhancement.

MRI: T1/T2: iso intense to CSF

DWI: no signalno contrast enhancement

DISCUSSION

There is no causal link between the temporal lobe

hypoplasia and arachnoid cysts appear despite their

association.

Hypothesis probable abnormalities of embryogenesis

that affects

Independently, and the formation of the arachnoid, and

the temporal lobe in some patients, is the effect of

compression KA.

The search for evidence in favor of either MRI or

hypogénésie compression of the temporal lobe by a KA.

DISCUSSION

In The hypoplasia of the temporal lobe, temporal

lobe concave next to the KA,

Discharge of the temporal horn and / or adjacent

structures;

sinuosity, ripple temporal cortex next to the KA.

Decrease in the volume of adjacent parenchyma.

Not discharge.

No thinning of cortical bone next to the KA.

DIFFERENTIAL DIAGNOSIS Epidermoid cyst:

Irregular edge in <cauliflower>, is insunie in tanks,

Includes vessels and nerves

Registered in 45% of cases at the basal cisterns.

  Light Flair hyperintense signal and Hyper Distribution.

Light Flair hyperintense signal and Hyper Distribution

DIFFERENTIAL DIAGNOSIS The chronic subdural hematoma: Lenticular, higher signal to CSF Subdural hygroma CAVITY porencephalic MEGAGRANDE TANK MALIGNANT CYSTIC NEURO-CYSTS ENTERIC CYST NEUROGLIAL

TRAETMENT

KA asymptomatic abstention

KA giant symptomatic or asymptomatic high

risk of bleeding:

       - Craniotomy + resection of the outer

mb

CONCLUSION

The MRI allows the diagnosis of intracranial

arachnoid cysts with characteristics of

specific sequences that can differentiate

epidermoid cysts.

With multi planar cuts it offers, it remains

the best technique to assess the extent and

anatomical relationships of these cysts.