Download
imaging modalities n.
Skip this Video
Loading SlideShow in 5 Seconds..
IMAGING MODALITIES PowerPoint Presentation
Download Presentation
IMAGING MODALITIES

IMAGING MODALITIES

3 Views Download Presentation
Download Presentation

IMAGING MODALITIES

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

  1. IMAGING MODALITIES • Computerized Tomography • Magnetic Resonance Imaging

  2. Advantages of C.T • Detection of calcification and calvarial defects • No contraindication

  3. Disadvantages of CT • Use of ionizing radiation • Reaction to iodinated contrast • Nephrotoxicity

  4. Advantages of MRI • No radiation • Excellent soft tissue resolution • Multiplanar imaging

  5. Limitations of MRI • Hyperacute bleed • Evaluation of calcification

  6. Contraindications for MRI • Cochlear implants • Cardiac pace maker • Neuro stimulator

  7. Lissencephaly • Most severe of neuronal migrational • abnormalities • Generalized paucity of gyral and sulcal • formation • Vertically oriented sylvian fissures

  8. Torch Infections • Toxoplasmosis • Rubella • Cytomegalovirus - Most common • cause of congenital CNS infection • Herpes simplex virus

  9. Focal cortical dysplasia • Common location – temporal lobes • Expanded gyrus with abnormally oriented • sulci and thickened cortex • Subcortical white matter hyperintensity • Surgical excision of dysplastic focus when • possible is often curative

  10. Cortical dysplasia – Balloon Cell Type of Taylor • Focal cortical thickening • Blurring of the gray-whitematter junction • Hyperintensity (on T2-weighted images)of • subcortical white matter often tapering • toward the ventricle

  11. Unilateral megalencephaly • Hamartomatous overgrowth of a part or whole of cerebral hemisphere • Ipsilateral migrational defects • Hypoplastic / hyperplastic white matter • Intractable seizures, hemiplegia and severe developmental delay

  12. Peri-Sylvian syndrome • Anomalous cortical development overlying • underdeveloped sylvian fissures • Dorsal perirolandic extension of sylvian • fissures

  13. Septo-optic dysplasia (de Morsier syndrome) • Partial or complete absence of septum • pellucidum • Squared off appearance of frontal horns • Hypoplasia of optic nerves and chiasm • ( 40-80%) • Hypoplasia of hypothalamus

  14. Tuberous sclerosis(Bourneville disease) • Incidence -- 1:10,000-50,000 • Inheritance -- autosomal dominant -- low penetrance -- chromosomes: 9, q32 - 34; 11, ??

  15. Tuberous sclerosis Clinical - “classic” triad of: > Papular facial lesions > seizures > mental retardation- 50% of patients

  16. Tuberous sclerosis • CNS lesions -Subependymal nodules - Giant cell astrocytoma - Cortical tubers - White matter lesions • Non- CNS lesions - Skin, kidneys, cardiovascular, Liver, spleen, pancreas and Musculoskeletal

  17. Sturge-weber syndrome (Encephalotrigeminal angiomatosis) • Inheritance : none • Clinical : port wine stain in CN - V distribution

  18. Sturge-weber syndrome • Aetiology - Normal cortical venous drainage fails to develop • Pathology - Leptomeningeal angiomatous vascular plexus with secondary dystrophic cortical changes

  19. Sturge-weber syndrome • Calcification • Atrophy • Enlarged med, sub-epen veins • Ocular lesions

  20. Periventricular leukomalacia • Commonly seen in premature infants • Ischemic lesions are most obvious in parieto-occipital regions • Paucity of white matter in the parieto-occipital regions • Indentation of the lateral ventricles

  21. Hippocampus Mean volumes: Right Left Male - 2.20+0.47cu.cm 2.17+0.72cu.cm Female- 2.27+0.47cu.cm 2.23+0.48cu.cm Hippocampal sclerosis: 1.46+0.60cu.cm

  22. Hippocampus Normal: NAA/Cho:1.20 + 0.27 Hippocampal sclerosis: NAA/Cho:0.99 + 0.14

  23. Hippocampus T2 Relaxometry Mean T2 time:110-115ms Prolonged in Hippocampal sclerosis

  24. Dysembryoplastic Neuroepithelial Tumor • Slow growing superficial lesions usually within temporal lobe but always supratentorial • Focal cortical lesion , hypointense on T1 & • hyperintense on T2 Wt.images • Surgery is curative