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Angiography….Limited to Angiography….Limited to stenosis. stenosis.
aneurysm & aneurysm & AVMAVM
Imaging TechniquesImaging Techniques
Plain ….Plain …. Normal….inner & outer tables (compact)Normal….inner & outer tables (compact) Diploic space ( spongy bone )Diploic space ( spongy bone ) Sutures remain visible even Sutures remain visible even after fusion. after fusion. Metopic suture. InconstantMetopic suture. Inconstant vascular impressionsvascular impressions arachnoid granulationsarachnoid granulations position of calc. pineal body.position of calc. pineal body.
Plain film…..cont.Plain film…..cont.
Abnormal plain films; look forAbnormal plain films; look for
SAH SAH usually due to rupture usually due to rupture aneurysm.aneurysm.
CT is the best initial exam.CT is the best initial exam.
The large aneurysms are seen by CT.The large aneurysms are seen by CT.
MRA can show smaller aneurysms.MRA can show smaller aneurysms.
Arteriography is the best.Arteriography is the best.
AVMAVM may present with Hge….CT can may present with Hge….CT can show the AVM esp. with contrast.show the AVM esp. with contrast.
But MRI is better even without But MRI is better even without contrast.contrast.
AbscessAbscess
Low density with ring enhancementLow density with ring enhancement
Herpes encephalitisHerpes encephalitis
enhancing low density areas in the enhancing low density areas in the
temporal lobes.temporal lobes.
Head Injury:Head Injury:FracturesFractures# more translucent# more translucent# may branch abruptly# may branch abruptly# have straight or jagged edge that fit # have straight or jagged edge that fit
together. While venous channels have together. While venous channels have undulating irregular edges which cannot undulating irregular edges which cannot be fitted together.be fitted together.
Arterial grooves have parallel sides (more Arterial grooves have parallel sides (more easily confused with #)..but present in easily confused with #)..but present in known anatomical positions.known anatomical positions.
Suture in known anatomical positions & Suture in known anatomical positions & show regular interdigitations. Widening of show regular interdigitations. Widening of a suture has the same significance as a #a suture has the same significance as a #
Depressed #....denseDepressed #....denseEDH can result from # through MMA groove.EDH can result from # through MMA groove.
CT in head injuryCT in head injuryCT should be done when there is:CT should be done when there is:-deterioration in the conscious level.-deterioration in the conscious level.-worsening of neurological deficits.-worsening of neurological deficits.
Extracerebral lesionsExtracerebral lesions-EDH.. -EDH.. biconvex. Associated with #biconvex. Associated with # High density for 2Wks.High density for 2Wks.After 3-4Wks…..hypodenseAfter 3-4Wks…..hypodenseIsodense in between. Isodense in between.
-SDH-SDH…….concavoconvex…….concavoconvex
Fractures of the base & vault are easily Fractures of the base & vault are easily seen in bone windowseen in bone window
Intracerbral lesions:Intracerbral lesions:-Edema- -Edema- homogenous low density.homogenous low density.-Contusions- -Contusions- patchy low density areaspatchy low density areas-Intracerebral hematoma-Intracerebral hematoma
Severe head injury can exist with no Severe head injury can exist with no abnormal CTabnormal CT