Transcript T2 weighted sagittal MRI

This version includes the instructor answer key; these are slides labeled “ANSWERS”.
MedNeuro Neuroimaging Lab
Mary Kate Worden, Ph.D., Dept of Neuroscience
and Myla Goldman, M.D., Dept of Neurology
Objectives:
1.
To review the planes of section and the appearance
of the CNS and PNS in different imaging modalities.
2.
To identify normal and abnormal structures in
neuroimages.
3.
To predict how neural lesions can give rise to
symptoms in patients.
Slide 1
Q1. Identify the imaging modality, orientation and plane of section for these images.
Q2. One of these patients has motor weakness and the other has sensory deficits.
Identify the abnormalities in these images and explain the symptoms.
A.
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B.
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Slide 2
Superior
Anterior
A.
Posterior
B.
T2 weighted sagittal MRI
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This patient has a syrinx
extending from T1-T3. It
appears as a white streak
within the center of the
spinal cord (white arrows).
Note: the abnormal
appearance of this patient’s
back is a side effect of
steroid treatment for another
medical issue.
ANSWER
Superior
Anterior
T2 weighted sagittal MRI
A.
This patient has bulging
discs at levels C4-C5 (white
arrows). These are
compressing the ventral
aspect of the spinal cord
(corticospinal fibers),
resulting in motor weakness
at levels at and below the
compression.
Note also a white plaque
within the spinal cord at C3
(black arrow). This patient
also has MS.
B.
Posterior
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ANSWER
Q3.Identify the internal carotid angiogram and the vertebral artery angiogram.
Q4. Identify PCA, ACA, vertebral arteries, internal carotid, superior cerebellar
artery, cortical branches of MCA, PCA, lenticulostriate arteries, ophthalmic artery,
basilar artery, posterior communicating artery, insular branches of MCA, and PICA.
(Hint: at least one artery listed cannot be seen. Why not?)
Slide 3
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The ophthalmic artery
cannot be seen in this
internal carotid angiogram
because it extends out of
the plane of the image
towards you. However, you
might see it in a lateral view.
ANSWER
The ophthalmic artery
cannot be seen in this
vertebral artery angiogram
because it arises from the
anterior (not the posterior)
circulation.
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ANSWER
Case study
A ten year old girl with a history of minimal health
care presents with low back pain, increased lower
extremity weakness, and incidence of bladder
incontinence.
Patient’s
lower back
Her neural shows decreased function in her dorsal
and plantal flexors bilaterally, decreased function of
the left quadraceps femoris musculature, decreased
reflexes (pateller and ankle) and sensory deficit
(decreased sensation to pin prick) of the left L5
dermatome. She also has focal hirsutism of the lower
back (indicated by arrow on image).
You send her to radiology (next slide).
Slide 4
Patient
Q5. Identify the imaging
modality, the orientation and the
plane of section.
Normal
Q6. Identify the structure
indicated by the arrows.
Slide 5
Q5. Both images on the previous slide are CT scans
showing a transverse section through lumbar spinal
cord. Both have identical orientation.
Anterior/ventral
Right
Left
Q6. The arrows
indicate an
abnormality: a boney
process extending
through the spinal
column, dividing it into
two hemicords. The
patient underwent
surgery to remove the
bone.
Posterior/dorsal
ANSWER
Patient
Normal
L5
Q7. Identify the modality of imaging, the orientiation and the plane of section.
What does the arrow point to in the image of the patient?
Q8. Identify the level of the conus medullaris in the patient and in the normal
image. At what level is a lumbar puncture performed?
Slide 6
Patient
Rostral/superior
Normal
Posterior
Anterior
L5
Caudal/inferior
Q7. Both MRI images are longitudinal sections through lumbar spinal cord in the
same orientation. The black arrow points to an abnormal boney process extending
through the spinal cord of the patient from anterior to posterior.
Q8. The conus medullaris (white arrow) is at level L3-L4 in the patient and at level
L1-L2 in the normal image. Lumbar punctures are performed at L3.
ANSWER
Neuroradiographs from this patient.
Q9. What do you think caused the abnormalities you see in
these images from this patient?
Q10. Explain why the clinicians who treated this patient
described her spinal cord as “tethered”.
Q11. How do these images explain her symptoms?
Slide 7
Neuroradiographs from this patient.
Q9. Abnormalities in this patient are likely to be developmental defects,
resulting from incomplete closure of the neural tube. Focal
hirsutism on the back is sometimes the only external sign of spinal
bifida.
Q10. The patient’s spinal cord is “tethered” because the abnormal bony
process fixes the spinal cord in place within the vertebral column.
This can stretch the spinal roots as the patient grows.
Q11. The patient’s symptoms are likely to be secondary to the
stretching of the spinal roots. Her symptoms were relieved to a
great extent by surgery that removed the boney process dividing
her spinal cord.
ANSWER
Q12. Identify the imaging modality and plane of section.
Q13. Which image is superior to the other?
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Q14. Identify the lesion and the arterial territory in which it is located.
Q15. Identify the cerebral peduncles, the third ventricle and the
lateral fissure.
Slide 8
Q12. MRI Axial section T-2 weighted (notice CSF is white in occipital horns)
Q13. Image on left is dorsal/superior to image on right.
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Q14. The red circles arrow indicates the lesion. It is located in MCA
territory.
Q15. Cerebral peduncles are indicated by solid white arrows. Third
ventricle is indicated by black arrows. Lateral fissure is indicated by
ANSWER
yellow arrowheads.
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Q16. Which of the following functions do you suspect might be impaired
in this patient? Explain.
sensory (if so, where?)
vestibular function
motor function (if so, where?)
language
Slide 9
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Q16. Which of the following functions do you suspect might be impaired
in this patient? Explain.
sensory: Yes, sensory function is likely to be impaired on right side of
body. The lesion located in the region of primary somatosensory cortex
vestibular function: No, vestibular nuclei and vestibular pathways are not
at this level of the neuraxis
motor function: Yes, motor function of the right side of the body is likely
to be impaired because the lesion is located in the region of the primary motor
cortex
language: Yes, lesion is located in the perisylvian areas on the lateral
ANSWER
aspect of the left hemisphere.
Authors of a study of schizophrenic patients measured the
“gyrification index” in each patient as the ratio of length of the inner
cortical contour to the length of the outer cortical contour.
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are needed to see this picture.
Q17. What is the imaging modality and orientation?
Q18. Which side of the brain did they measure in these images?
Q19. Identify the internal capsule. What is the internal capsule
composed of?
Slide 10
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Q17. What is the imaging modality and orientation? T-1 MRI, coronal
sections
Q18. Which side of the brain did they measure in these images? Left
Q19. Identify the internal capsule. What is the internal capsule
composed of? See red arrows. The internal capsule is composed of myelinated
fibers carrying sensory information ascending to the brain and motor information
descending from the brain.
ANSWER
Authors of a study of schizophrenic patients measured the
“gyrification index” in each patient as the ratio of length of the inner
cortical contour to the length of the outer cortical contour.
QuickTime™ and a
TIFF (LZW) decompressor
are needed to see this picture.
Q20. What lobe(s) of the brain are measured in the anterior segment
image? In the posterior segment image?
Q21. What would you estimate the “gyrification index” to be in these
images?
Slide 11
Authors of a study of schizophrenic patients measured the
“gyrification index” in each patient as the ratio of length of the inner
cortical contour to the length of the outer cortical contour.
QuickTime™ and a
TIFF (LZW) decompressor
are needed to see this picture.
Q20. What lobe(s) of the brain are measured in the anterior segment image?
frontal lobe In the posterior segment image? frontal and temporal lobes
Q21. What would you estimate the “gyrification index” to be in these
images? Actual values reported in the study were in the range 2.0 to 2.7
ANSWER
The authors of this study reported that schizophrenics have a lower
gyrification index than normal patients.
Sallet et al (2003) Am J Psychiatry 160:1606-1613, Reduced cortical folding in
schizophrenics: An MRI morphometric study
Q22. Do you think that the degree of structural abnormality might
correlate with the degree of symptoms in these patients? Why or
why not?
QuickTime™ and a
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are needed to see this picture.
Q23. What do you think caused the the structural abnormalities
reported by these authors?
Slide 12
The authors of this study reported that schizophrenics have a lower
gyrification index than normal patients.
Sallet et al (2003) Am J Psychiatry 160:1606-1613, Reduced cortical folding in
schizophrenics: An MRI morphometric study
Q22. Do you think that the degree of structural abnormality might
correlate with the degree of symptoms in these patients? Why or
why not?
Brain dysfunction sometimes correlates with gross
structural abnormalities but sometimes does not.
The authors of this study reported structural
abnormalites were found in the left (but not the
right) hemispheres of disorganized schizophrenics.
No abnormalities were found in other groups of
schizophrenic patients (for example, paranoid
schizophrenics had normal gyrification indices). In
In other diseases such as Parkinson’s or Huntington’s or Alzheimers, gross
abnormalities may appear in late stages of the disease but not in early stages.
PET scans can sometimes reveal abnormalities of brain metabolism that are not
obvious from structural studies conducted by CT or MRI imaging.
QuickTime™ and a
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Q23. What do you think caused the the structural abnormalities
reported by these authors? Most likely: neurodevelopmental abnormalities.
These might include errors in neuronal migration and/or formation of cortical lamina.
ANSWER