Neuroradiology of Stroke and Headaches

Learning Objectives Identify T1 and T2 sequences Recall the normal anatomy of the intracranial circulation Apply appropriate CT and MR imaging of the brain in acute stroke

Learning Objectives Differentiate acute from chronic infarct on CT Classify primary and secondary headaches Formulate appropriate imaging algorithms for headache

Learning Objectives Recognize subarachnoid hemorrhage on noncontrast head CT State common locations of intracranial aneurysms Describe treatment options for patients with intrcranial aneurysms

What type of imaging modalities are used to evaluate the brain in patients presenting with acute stroke?

Axial NECT head

What is the most sensitive method for detection of acute ischemia in the brain?

Describe factors which influence which modality is chosen to image patients with acute stroke.

What modalities can be used to evaluate the cerebral vasculature?

Pros and Cons of Vascular Exams MRA/MRV CTA/CTV Catheter based Angiogram or Venogram

Pros and Cons of Vascular Exams MRA/MRV Noninvasive/Minimally Invasive (if iv contrast) No radiation No contrast Exam times long Cooperation needed/quality inconsistent Not always available in some centers CTA/CTV Minimally invasive (iv required) Quick Immediately available Radiation dose Contrast required Catheter based Angiogram or Venogram Gold standard High resolution of vascular detail Offers endovascular access if needed Invasive Morbidity/Mortality Necessitates angiography team Expensive

ACA MCA ICA vert PCA basilar SCA AICA PICA

ACA MCA ICA basilar PCA vert

What vessel connects the anterior and posterior circulation What vessel connects the anterior and posterior circulation? Where would you draw it?

Describe a clinical scenario where MRA is indicated.

lateral oblique coronal

MRV superior sagittal sinus superior sagittal sinus transverse sinus torcula sigmoid sinus Internal jugular superior sagittal sinus transverse sinus Internal jugular torcula internal cerebral veins straight sinus sigmoid sinus vein of Galen MRV

How might this patient have presented? Axial NECT head How might this patient have presented?

Axial NECT head What are the findings?

Normal extracellular space Normal neuron extracellular diffusion > intracellular diffusion Cytotoxic Edema in Infarction swollen neuron Extracellular space decreased and diffusion limited

At what point after the onset of stroke like symptoms does DWI become positive?

55 yo female with new right hemiparesis, right neglect and expressive aphasia

Explain the discordance in the findings between these two studies. MRI Axial DWI Axial NECT head

What is in your differential diagnosis? 67 yo male with 2 hours of new onset of right sided weakness. What is in your differential diagnosis?

What imaging study would you order?

67 yo male with 2 hours of new onset of right sided weakness

What occurred in the interval? Coronal NECT head Axial NECT head What occurred in the interval?

What are the signs of mass effect? Coronal NECT head Axial NECT head What are the signs of mass effect?

How does hemorrhagic transformation of ischemic infarct occur?

Acute vs. chronic Axial NECT head Coronal NECT head

Acute vs. chronic MRI axial DWI MRI axial T2 MRI axial ADC

What is in your differential diagnosis? 19 yo female c/o headache gradually worsening over 3 days and decreased visual acuity. She is obese, takes oral contraceptives and has papilledema on phys exam. What is in your differential diagnosis?

What type of imaging examination should be ordered?

Axial NECT head

Normal Patient

What are the patient’s risk factors?

What are other risk factors associated with venous sinus thrombosis?

Now let us turn to this patient’s MRI Now let us turn to this patient’s MRI. What do we expect to see on the DWI?

Can you give examples of other secondary headaches?

What are examples of primary headaches?

What should be done next for this patient? 41 yo male with sudden onset of severe h/a. Denies history of h/a in past. What should be done next for this patient?

When should a non-enhanced CT head be ordered in the clinical setting of headache?

41 yo male with sudden onset of severe headache. Axial NECT head

What imaging examination should be performed next?

What if the CT angiogram is negative?

What are the treatment options for ruptured aneurysm?

What are the advantages and disadvantages to each?

Axial NECT head bone window AP XR skull

What are the most common locations of intracranial aneurysms? Why?

How do aneurysms cause headaches?

What examinations can be used to detect aneurysms?

Aneurysm found on screening MRA. Where is it located? MRA axial source images MRA MIP

Who is at increased risk for developing aneurysms?

Who should be screened?

What is the preferred modality for aneurysm screening?

52 y.o. male w/hx of 4 mm right paraophthalmic aneurysm found on CT angiography performed after high speed MVA resulting in skull base fractures. Sagittal CT angiography Coronal CT angiography

54 yo female w/ long hx of h/a, photophobia and phonophobia Primary or secondary headache?

What are the indications to order an MRI in the clinical setting of headache?

54 yo female w/ long hx of h/a, photophobia and phonophobia

Primary or secondary h/a? 54 yo male with 2 wks of fever, malaise and h/a. Now has increasing right arm and right facial weakness. PMHx of IVDA which currently denies. Primary or secondary h/a?

What is in your differential diagnosis?

What type of imaging study would you order?

T1 T1 gad 2 weeks fever, malaise and h/a. Now with increasing right arm and right facial weakness T2

How would you describe this lesion? T1 gad How would you describe this lesion? MRI axial T1 MRI axial T1 gad T2 MRI axial T2 MRI axial DWI

How does the restricted diffusion shape your differential? T1 gad How does the restricted diffusion shape your differential? T1 T1 gad T2 T2 DWI

Why is this NOT an infarct? T1 gad Why is this NOT an infarct? T1 T1 gad T2 T2 DWI

End.