from Neuroradiology: head and neck
Published online by Cambridge University Press: 05 March 2013
Imaging description
Globe injuries often present with subtle or confusing appearances on CT. A systematic approach is useful, paying particular attention to the anterior chamber, the lens, the vitreous body, the shape of the globe, and the presence of foreign objects.
The anterior chamber should be scrutinized with respect to size and attenuation. Decreased depth of the anterior chamber may be caused by a full-thickness corneal laceration or by anterior dislocation of the lens (Figure 16.1). Increased depth of the anterior chamber may be seen with a posterior globe rupture [1]. The change in depth may be subtle, and it is most helpful to compare with the contralateral globe. Increased attenuation within the anterior chamber indicates the presence of hemorrhage, known as a hyphema (Figures 16.2 and 16.3).
Injury to the zonular attachments of the lens may result in posterior (more common) or anterior lens dislocation, and dislocations may be partial. Trauma to the lens capsule may result in the influx of fluid, leading to hypoattenuation of the lens; this is known as a traumatic cataract (Figure 16.4).
The posterior chamber may rupture, producing deformity along the posterior margin of the globe. There may also be detachment of the vitreous, choroid, or retina (Figure 16.5). Each type of detachment demonstrates a different morphology. Vitreous detachment usually begins posteriorly and crosses the optic disk. Choroid detachment extends anteriorly to the margin of the lens, and diverges posteriorly as it approaches the optic disk (Figure 16.6). Retinal detachment extends anteriorly to the ora serrata, and converges posteriorly on the optic disk (Figure 16.7).
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