james chen - head and neck imaging.pdf

8/10/2019 James Chen - Head and Neck Imaging.pdf

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HEAD AND NECK IMAGING

James Chen (MS IV)Anatomy CourseJohns Hopkins School of Medicine Sept. 27, 2011


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O BJECTIVES ! Introduce cross sectional imaging

of head and neck! Computed tomography (CT)

! Review head and neck anatomy! Major anatomical landmarks on

imaging! Bone

! Ventricles! Brain! Vessels


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C ROSS SECTIONAL VIEWS Sagittal

Superior

Inferior

A P

Coronal

Superior

Inferior

R L

Axial

R L

Posterior

Anterior


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INTRODUCTION TO CT:RULES OF LIGHT AND DARK

! Bright = high density! Bone

Axial


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Calvarium appears bright (Bone)

! Bright = high density! Bone

Axial


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! Bright = high density! Bone! Blood

Axial


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Parenchymal Hemorrhage (Blood)

! Bright = high density! Bone! Blood

Axial


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! Bright = high density! Bone! Blood! Bullets (hardware)

Axial


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Bullet note artifact from metal

! Bright = high density! Bone! Blood! Bullets (hardware)

! Dark = low density! Air! Water (fluids)

! Gray = in between! Soft tissue

Axial


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Bone Window Brain Window

! Image brightness/contrast adjusted toaccentuate particular structures

INTRODUCTION TO CT:WINDOWING


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Non-contrast Contrast

! Intravenous contrast makes vessels bright

INTRODUCTION TO CT:C ONTRAST


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NECK IMAGING ! Cervical vertebrae

! Cross sectional anatomy

! Vasculature! Carotid arteries! Vertebral arteries


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C ERVICAL VERTEBRAE

Sagittal (bone window)


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C ERVICAL VERTEBRAE ! Articulation allows

head movement! C1 - atlas! C2 axis

! Protects vital neuraland vascularstructures! Cervical spinal cord! Vertebral arteries

! Damage can result insignificant morbidity

Sagittal (bone window)


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Sagittal Coronal

Dens


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Sagittal Axial

Which cervical vertebral level is this axial section?


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Level of Atlas

Dens

TransverseForamen

CervicalCord

Axial


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NECK IMAGING ! Cervical vertebrae

! Cross sectional anatomy

! Vasculature! Carotid arteries! Vertebral arteries


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C ERVICAL VESSELS ! Large vessels of the neck deliver blood

supply to the brain

! Anterior and posterior circulations! Anterior : Carotid arteries! Posterior : Vertebral arteries

! Disrupted flow can result in significantmorbidity


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VASCULATURE:C AROTID A RTERIES

Sagittal Coronal


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Sagittal Coronal

VASCULATURE:C OMMON C AROTID A RTERIES


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VASCULATURE:INTERNAL C AROTID A RTERIES

Sagittal Coronal


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VASCULATURE:EXTERNAL C AROTID A RTERIES

Sagittal Coronal


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Vertebral Arteries (coronal) Vertebrobasilar arteries (coronal)

VASCULATURE:VERTEBRAL A RTERIES


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VASCULATURE:AXIAL IMAGES

Axial Coronal


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Common Carotid Arteries Below carotid bifurcation


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Below carotid bifurcationVertebral Arteries


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Axial Above carotid bifurcation


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External carotid arteries Above carotid bifurcation


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Internal carotid arteries Above carotid bifurcation


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Vertebral arteries Above carotid bifurcation


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C ASE:ARTERIAL A BNORMALITY

Axial

Abnormal Normal

Which vessels are these?


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C ASE:C AROTID A RTERIES

Axial

Calcifications inatherosclerotic plaques


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C ASE:C AROTID A RTERIES

Axial! Which vessels are affected

by atherosclerosis! A. Vertebral arteries

! B. Common carotid arteries! C. External carotid arteries! D. Internal carotid arteries

! Internal POSTERIOR to externalcarotid artery above bifurcation


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HEAD IMAGING ! Paranasal Sinuses

! Bony walls and contents

! Ventricles! Normal vs. Enlarged

! Parenchyma ! Basic anatomy and midline shift

! Vasculature! Hemorrhage types


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PARANASAL SINUSES ! Paired air-filled spaces around nasal cavity

! Frontal, ethmoid, sphenoid, maxillary

! Normal varies! Development occurs prenatally and after birth! Shape and size of sinuses can differ between people

! Things to look for:! Are the bony walls intact?! Is there anything in the sinus (air will appear black)?


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SINUSES:SPHENOID

Sagittal Coronal


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SINUSES:SPHENOID

Sagittal Coronal Axial


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SINUSES:SPHENOID



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SINUSES:ETHMOID

Sagittal Coronal


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SINUSES:ETHMOID



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SINUSES:ETHMOID



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SINUSES:MAXILLARY

Sagittal Coronal


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SINUSES:MAXILLARY



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SINUSES:FRONTAL

Sagittal Axial


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SINUSES:FRONTAL

Sagittal Axial


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C ASE:SINUS A BNORMALITY

Left Maxillary Sinus Right Maxillary Sinus(Normal)

Sagittal Sagittal


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Sagittal ! What is the likelycause of theabnormality?!

A. Neoplastic! B. Trauma! C. Infection! D. Endocrine

C ASE:FACIAL FRACTURE

Fracture in anterior wall of left maxillary sinus

Axial


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C EREBRAL VENTRICLES ! Anatomy

! Lateral ventricles (paired)! Third ventricle! Fourth ventricle

! Cerebrospinal fluid! Produced in choroid plexus (lateral +

third ventricles)

! Approach on axial images! Ventricles midline and symmetric?! Ventricles normal size?! Abnormal ventricle contents?

R L

Superior

Inferior


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VENTRICLES SYMMETRIC?AxialSagittal


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VENTRICLES SYMMETRIC?

Lateral ventricles symmetric

AxialSagittal


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AxialSagittal

VENTRICLES IN MIDLINE?


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AxialSagittal


Choroid plexus (lateral ventricles)

bright from calcium


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AxialSagittal


Ventricles equidistant from midline


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NORMAL VENTRICULAR SIZE?

Enlarged (Hydrocephalus)Normal

Axial Axial


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ABNORMAL VENTRICLE C ONTENTS?

Normal CSF (dark)

Axial Axial


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BLOOD IN VENTRICLES

Intraventricular blood (bright)

Axial Axial

Normal CSF (dark)

IntraventricularCatheter (helps

reduce pressureby draining CSF)


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BRAIN PARENCHYMA ! Basic anatomy

! Cerebral hemispheres divided by falx cerebri


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! Cerebral hemispheres divided by falx cerebri

Falx cerebri is dural fold separatingleft and right hemispheres


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! Cerebral hemispheres divided by falx cerebri! Cerebral cortex superior to brainstem and cerebellum

Ax Sag


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! Cerebral hemispheres divided by falx cerebri! Brainstem and cerebellum inferior to cerebral cortex

Ax Sag

CerebrumCerebrum (temporal lobes)


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Ax Sag

BrainstemBrainstem


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Ax Sag

CerebellumCerebellum


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BRAIN PARENCHYMA ! Normal changes with age

! Brain mass decreases! Surrounding CSF spaces appear larger (enlarged sulci,

ventricles)

20-years-old 80-years-old


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BRAIN PARENCHYMA ! Elements to consider on imaging:

! Symmetry?! Falx cerebri in midline?! Abnormal mass (variable brightness) or edema

(darker)?! Hemorrhage (bright)?


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C ASE:BRAIN A BNORMALITY

Axial

Abnormal Normal

Axial


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! What abnormalitiesare present?! A. Compression of left

lateral ventricle! B. Intraventricular

hemorrhage! C. Midline shift! D. A and C

Axial


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! What abnormalitiesare present?! A. Compression of left

lateral ventricle! B. Intraventricular

hemorrhage! C. Midline shift! D. A and C

Axial


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C ASE:INTRACRANIAL A BNORMALITY

! What is the cause ofthe mass effect?! A. Trauma

! B. Hemorrhage! C. Congenital! D. Tumor

Axial


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Axial

Large mass in left frontal lobe


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Axial

Significant edema related to mass


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Axial

Significant edema related to mass


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! Ventricles! Size and symmetry


! Vasculature! Hemorrhage


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INTRACRANIAL BLEEDING ! Common use of non-contrast head CT

! NEW blood appears BRIGHT (acute bleed)! OLD blood can be DARK (old bleed)

! Different locations

Epidural Subdural Subarachnoid Parenchymal

Outside brain parenchyma


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ARTERIAL hemorrhage


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VENOUS hemorrhage


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SUMMARY ! Rules of CT

! High density = Bright (Bone, blood, bullets)! Low density = Dark (Air, CSF, edema)

! Normal anatomic landmarks on cross-sectionalimaging

Bone Brain/Ventricles Vessels


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THANKS ! Questions "

! [email protected]

! Good luck on the rest of anatomy!

james chen - head and neck imaging.pdf

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