jurding radiologi

5/19/2018 Jurding radiologi

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IMAGING of the POST-

OPERATIVE CRANIUM

Supervisor: dr. Yanto Budiman,

Sp.Rad, M.Kes

Audrey G. Sinclair, MBBCh, MRCP, FRCR Daniel J. Scoffings, MBBS,MRCP, FRCR


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Introduction

Imagingroutine post op neurosurgery fol-up

CT1st line imaging to evaluate complications

Fast, cost effective, easily accessible.

MRI

Higher sensitivity for detecting post-op infection &

ischemia


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Discuss:

The surgical techniques

N post-op imaging appearances of burr holes,

craniotomy, craniectomy, cranioplasty

Describe the appearances of post-op

complications


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Normal anatomy

Scalp AP-ly from the supraorbital ridge to

the sup nuchal line, lat-ly to the

zygomatic arch & EAM.

5 layers (skin, SC, galea

aponeurotica, loose areolar connective

tissue, pericranium)

3 primary muscle groups (frontalis,

occipitalis, temporalis)


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Galea aponeurotica

A layer of thick fibrous tissue

Cont w/ the occipitofrontalis & auricularis

muscles.

Temporalis muscle arises from the temporal fossa

pericranium & lies deep to the temporalis fascia,continuous w/ the galea superiorly.


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Subgaleal spaceeasily dissected, allows

fluid to accumulate & spread across thecranium.

Pericranium : Adheres to the margins of the underlying skull

bones at the suture lines.

Isntusually visible as a separate structure unless

an underlying hematoma is present.


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Duramater :

Tough 2-layered membrane.

Outer layerby the periost of the inner table of

the calvaria

Inner layerthe duramater proper

Lacks a BBBenhances after IV contrast inj(most prominent in the segments over the

convexities)

Arachnoid & piamater arent normally visible at

imaging.


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Burr Holes

Small hole

Created in the calvaria with a surgical drill

To insert a device (eg, a ventricular drain/shunt

catheter, endoscope, ICP monitoring devic/deepbrain stimulator electrode)

Provide access for stereotactic brain biopsy

To drain a chronic subdural hematoma

A prelude to the formation of a craniotomy flap


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Complications

Infection, skull #, hemorrhage.

Plunge the drill into the cranium, breach theduramater & cause ICH.

T2W MRI, a defect caused by plungingarea of

high-signal-intensity edema underlying the burrhole (mushroom sign).

Growing burr hole.


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CRANIOTOMY


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Indications and Techniques

Surgical removal

portion of skull

Bone flap replaced

end of procedure


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Normal Appearance

Artifactmetal

clips

Scalp swelling

Tram-track

discontinuity

Small extra-axial

fluid collection


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Normal PostOperative Enhancement

Neovascular

Granulation Tissue

1st year after surgery

Duramater40

year

Brain resection< 1

month


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Normal Pneumoenchepalus

Inevitable

Most often subdural,

frontal lobe

< 3 weeks


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Complication

Tension Pneumoenchepali

Most Often: posterior fosa

craniotomy

Peaking sign

Mount Fuji sign

Treatment : Conservativeatau surgical


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Complication

Soft Tissue Infection


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Complication

Bone Flap Infection

Manifestation : 1- 2

weeks after infection

Causes : Bakteri Gram +

(S.aureus)

CT : abnormal texture and

lytic area

MRI : > in T2


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POSTOPERATIVE HEMORRHAGE


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Postoperative Hemorrhage

1.1% of postcraniotomy intracranialhematomassurgical

In this studyhematomas intraparenchymal

43% , extradural 33%, subdural 5%, and mixed8%.

The frequency variestype of surgery

meningioma resection 6.2%7.1% Symptoms: focal neurologic deficit,

consciousness, seizure


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Extradural Hematomas

Occur between the outer periosteal layer ofthe dura mater and the inner skull.

Regional (62,5%) : occur just under the bone

flap Adjacent (31.3%): occur at the craniotomy

margins, most often posteriorly

Remote (6.3%) :occur distant from thecraniotomy site. Multiple remote hematomasmay be present


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Regional Adjacent


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Intraparenchymal Hemorrhage.

Post-op intracranial10,8%

Majority were small (5cm)poorer outcome

Causes :incomplete hemostasis in the surgical

bed, incomplete tumor resection, postoperative

hypertension, and bleeding diatheses.


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Remote Cerebellar Hemorrhage

Rare, usually benign, self-limiting complication

Most often occurs after supratentorial

craniotomy

Symptoms :consciousness, gait ataxia,

weakness


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Remote Cerebellar Hemorrhage

Streaky curvilinear areas of increased attenuation in

the cerebellar sulci and foliazebra sign

May be unilateral or bilateral

Most often involves the superior aspect of thecerebellum


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Craniectomy

Is a removal of a portion of the skull without

subsequent replacement of the bone

Remove an infected bone flap, tumor that has

infiltrated the calvaria, primary procedure to

decompress intracranial contents.

The bone flap from craniectomy is not

discardedmay be stored in an abdominal

subcutaneous pocket or frozen in a bone bank


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Craniectomy (normal appearance)

Normal postcraniectomy imaging appearancesdepend partly on what is done with the duramater.

Duramater open, the subarachnoid spaceherniate outward through the defectpseudomeningocele

In most patients, craniectomy obliterates the

subgaleal spacemeningogaleal complex(galea,subgaleal connective tissue, fibrosis, andduramater)


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CT scan: meningogaleal complexsingle

layer of smooth, curvilinear, slightly

hyperattenuating tissue that demonstrates

mild enhancement


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Complication

Extracranial Herniation

Defect too small the swollen brain may herniate

through the defect (27.8%)

Subdural and Subgaleal Hygromas

Disturbance of CSF circulation after craniectomy

subdural or subgaleal hygroma (21.3% -50%)

ipsilateral

Appear within days of surgeryresorb over a

period of weeks - months.


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CT scanlow-attenuation fluid collections

deep to the galea or in the subdural space


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External Brain Tamponade

Rarepotentially life-threatening

complicationpressurized subgaleal fluid

collection

Diagnostic criteriatense craniectomy flap,

neurologic, subgaleal fluid collection with

an associated mass effect on the underlying

brain, and neurologic after drainage of thefluid collection.


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CT scan : bulging skin flap seen with a

subgaleal fluid collection that compresses the

brain at the craniectomy site


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Trephine Syndrome

Manifests :headaches, seizures, dizziness, undue

fatiguability, mood changes, and, often, a sunken

appearance of the skin flap

CT and MR imaging show a depressed skin flap at thecraniectomy site and concave deformity of the

adjacent brain


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Paradoxical Herniation.

Large craniectomy defectCSF drainage CSF

pressureintracranial pressure cause subfalcine

and transtentorial herniation away from the craniectomy

defect and results in mesodiencephalic dysfunction

Paradoxical herniation is a neurosurgical emergency.

Urgent treatment : intracranial pressure, stop any CSF

leakage, and restore the continuity of the calvaria.


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Paradoxical Herniation.

CT scan : a sunken skin flap + herniation of the brain

away from the craniectomy defectmidline shift,

compression of the midbrain, and effacement of the

basal cisterns


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CRANIOPLASTY


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Indications

Surgical Repair of skull defect

Cosmesis, relieve discomfort, normal ICP,

Ideal : good contour, protector, osteogenic,

biocompatible, good imaging

Types : autologous, acrylic, titanium


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Autologous


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Autologous


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Autologous


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Acrylic

Resin methylmethacrylate (MMA) with(out)

prefabricated acrylic plate

Acrylic cranioplasties are radiolucent

MMA contain gas bubbles


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Signal Void

(arrowhead)

+ Less in weight

+ Easy to shape.

+ Less reaction..

+ Most used material!


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Titanium

Resists corrosion, nontoxic, no inflammatory reaction!


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Titanium


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Complications

Infection! Autologous 5,5-26%, Acrylic 5-20%,Titanium 2,6-16,6%

Th/ Remove the cranioplasty!

Fluid collections (sterile/empyema) may be insubgaleal, extradural, or subdural

Bone resorbtion (autologous)

Acrylic fracture


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Conclusions

1. Learn the normal brain CT & MR

2. Aware of the complications to prevent delay

of diagnosis & treatment

3. CT is fast, accessible and cost effective

4. MR is more sensitive and reliable

jurding radiologi

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