Early imaging findings in acute cerebral infarction seen on CT and MRI include loss of gray-white interface, sulcal effacement, and acute hypoattenuation on CT. Diffusion weighted MRI is highly sensitive in detecting acute infarction within hours by showing restricted diffusion. Follow up imaging may show hemorrhagic transformation between 1-5 days as the infarct evolves. Location and imaging characteristics can help determine the underlying cause of intracerebral hemorrhage such as hypertensive bleeds in the basal ganglia versus traumatic hemorrhages at cortical surfaces.

1. Imaging in stroke. DR.SRIRAMA ANJANEYULU

3. Early Stroke-CT finding Obscuration of the outline of lentiform nucleus

8. Acute One Day Old Infarction Involving the Right MCA Territory A. DW image shows area of infarct as bright signal. B. T1 image shows no e/o blood in the area of infarct. C. Post contrast coronal image shows vascular enhancement in the area of infarct. D. MR angiography shows right middle cerebral artery branches to be narrower in calibre, as compared to left.

10. MCA infarct with mass effect on the body of the lateral ventricle.

11. 3 Wk Old Subacute Infarct Involving The Right MCA Territory A.DW image reveals bright signal involving the cortex. This is from restricted diffusion secondary to acute stroke. B. Flair image shows bright signal in the posterior parietal cortex with gyral thickening. C. T1 weighted image shows bright signal in the same area from blood. D. Post contrast study shows bright signal in the same areas. Enhancement is obscured by the presence of blood.

14. Initial non-contrast head CT scans of 2 pts with stroke presenting with L-sided weakness. The pt in (A.) has an ischemic stroke in the R hemisphere which is not yet visible on CT imaging early after onset while the pt in (B.) has evidence of a R hemisphere IC bleed.

20. Non-contrast CT scan of the brain demonstrating SAH in a pt with the sudden onset of a severe headache and stiff neck 1 hr prior to this scan.

21. Head CT without contrast shows diffuse SAH. Subsequent CT angiographic image (with contrast agent) in the same pt demonstrates an anterior communicating artery aneurysm.

22. Non-contrast CT of the brain demonstrating L-sided subdural fluid collection with midline shift in a patient presenting with 30 mts of confusion and R sided weakness that completely resolved.

24. Left parietal hemorrhage with break through into left lat.ventricle. Arrowheads point to hemorrhagic infarct with extension of blood into lat.ventricle.

25. Non-contrast CT scans of the brain demonstrating typical locations of hypertensive-related ICH: (A) thalamus, (B) putamen (C) pons and (D) cerebellum

27. Acute hematoma. There is a central area that is isointcnse to brain in Tl-W image and hypointcnsc in T2-W image, consistent with intracellular deoxy Hb, and a peripheral area that is hyperintense in both Tl and T2 images, consistent with extracellular met hemoglobin.

28. Angiogram of AVM with draining vein MRI Image of an AVM

29. T2-W brain MRI demonstrating a cavernous malformation (arrow) with surrounding edema. The patient had presented 4 months prior with an ICH in the same location, but initial MRI failed to demonstrate this lesion as it was obscured by blood at the time.

30. Non-contrast CT scan of the brain demonstrating a L-sided lobar ICH. MRI and brain biopsy revealed the etiology to be from an underlying metastatic tumor in the setting of newly-diagnosed RCC.

31. Typical lobar hemorrhage Typical small thalamic bleed