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154

 

D.T. Ginat et al.

 

 

 

4.17\ Duraplasty and Sealant

 

(Fig. 4.44). Associated dural enhancement can be

Agents

 

seen in over 10% of cases. The dural regenerative

 

 

matrix intentionally resorbs at a similar rate as

4.17.1\ Discussion

 

the new tissue that forms, thus preventing encap-

 

 

sulation. Specifically, the collagen matrix typi-

Duraplasty consists of reconstructing the dura

cally resorbs within 1–6 months, depending on

following cranial surgery in order to minimize

the particular type.

cerebrospinal fluid leakage. Several dural substi-

Polytetrafluoroethylene (Gore-Tex) sheets

tutes and sealant agents are commercially avail-

appear as high attenuation on CT and very low

able, including bovine pericardium, elastin-fibrin,

signal on T1-weighted and T2-weighted MRI

biosynthetic cellulose, polytetrafluoroethylene,

sequences (Fig. 4.45). Small collections of cere-

and collagen matrix sheets, among others.

brospinal fluid form adjacent to the duraplasty in

Some formulations of collagen matrix dura-

15% of cases. Often, thin membranes of granula-

plasty have a spongelike consistency, while oth-

tion tissue form between the duraplasty and the

ers are more flat and compressed. These materials

surface of the brain. In general, complications

appear as a low attenuation on CT and often of

related to duraplasty procedures are infrequent

low-to-intermediate signal intensity

on both

and include graft failure with pseudomeningo-

T1-weighted and T2-weighted MRI

sequences

cele formation, epidural fibrosis, and infection.

4  Imaging the Postoperative Scalp and Cranium

155

 

 

a

b

d

c

Fig. 4.44  Collagen matrix duraplasty. The patient has a history of a large left frontal meningioma status post resection and duraplasty using DuraGen. CT image (a) shows the sheetlike low-attenuation duraplasty material (arrows) in the left frontal region. T2-weighted (b) and

post-contrast T1-weighted (c) MRI sequences show that the duraplasty material (arrows) displays low T2 and intermediate T1 signal. Photograph of suturable DuraGen (d) (Courtesy of Patricia Smith and Sarah Paengatelli)

156

D.T. Ginat et al.

 

 

a

b

Fig. 4.45  Polytetrafluoroethylene (Gore-Tex) duraplasty. Coronal CT image (a) demonstrates high-attenuation duraplasty (arrow) after hemicraniectomy. On the T2-weighted MRI (b), the material (arrow) displays low signal

4  Imaging the Postoperative Scalp and Cranium

157

 

 

4.18\ Intracranial Pressure

Monitors

4.18.1\ Discussion

Conditions associated with raised intracranial pressure, such as hemorrhage, cerebral infarcts, or trauma, can compromise cerebral blood flow. A variety of intracranial pressure monitors are available, including fiber optic monitors. The filamen-

a

tous fiber optic monitor enters the ­intracranial cavity through a bolt that is introduced into a burr hole (Fig. 4.46). Other devices for measuring intracranial pressure include diaphragm-type monitors and ventricular catheters with pressure sensors. Pressure monitors can be placed in the subarachnoid or subdural space, brain parenchyma, or ventricle. The components of the monitors are readily apparent on CT, allowing the precise position to be determined.

b

Fig. 4.46  Intraparenchymal pressure monitor. The patient has a history of severe traumatic brain injury resulting in a left subdural hematoma and intraparenchymal contusions. Sagittal CT image (a) shows the pressure bolt monitor seated in the burr hole through which a fiber

optic monitor enters the brain parenchyma (arrow). Photograph of a Camino Bolt and pressure monitor and fiber optic (inset) (Codman Neuro New Brunswick NJ) (b) (Courtesy of Justin Hugelier)