Fig. 6.1
Pigment membrane melanoma in left eyeball. (a) Axial T1WI MR shows a fusiform hyperintensity on the posterior wall of the left eyeball; (b) oblique-sagittal T1WI MR displays hyperintense signal inferior to the optic disc; (c) axial T2WI MR shows homogenous hypointensity; (d) axial T1 Contrast MR with fat saturation shows homogenous enhancement
Fig. 6.2
Pigment membrane melanoma in left eyeball. (a) Axial T1WI MR shows hemispheric hyperintense signal on the posterior wall of the left eyeball; (b) axial T2WI MR displays homogenous low signal with retinal detachment; (c) the selection of ROI on DCE MRI; (d) the TIC on DCE MRI reveals enhancement within the lesion
6.1.4 Conclusions
Pigment membrane melanoma is characterized by high signal on T1WI and low signal on T2WI in fusiform or mushroom-shaped appearance. It is not difficult for typical ones to differentiate from other lesions within the eyeball. The influence of the distribution and content of melanin on MR signal intensity may challenge the imaging diagnosis.
6.2 Choroidal Hemangioma
6.2.1 Pathology
- 1.
A benign, vascular hamartomatous lesion is actually cavernous hemangioma in most cases.
- 2.
No pigment, round or oval orange or sallow flat lesion, often with retinal detachment.
- 3.
Tumors are divided into two categories of solitary and diffusive one (Singh et al. 2005).
6.2.2 Imaging Examination Recommendations
- 1.
US should be the first choice of examination due to its convenience.
- 2.
MRI can become one of the preferred examination methods for those suspected cases difficult to diagnose.
- 3.
CT has limited value due to its poor sensitivity and specificity.
6.2.3 Imaging Findings
MRI findings: The lesion shows fusiform or crescent appearance with well-definition and demonstrates homogenous iso-hypointense signal on T1WI and homogenous hyperintense signal on T2WI, and strong enhancement on contrast MRI (Figs. 6.3 and 6.4).
Fig. 6.3
Choroidal hemangioma in left eyeball. (a) Axial T1WI MR shows crescent isointense signal on the posterior wall of the left eyeball; (b) axial T2WI MR reveals homogenous hyperintense signal; (c) axial T1 Contrast MR with fat saturation shows homogenous significant enhancement
Fig. 6.4
Choroidal hemangioma in left eyeball. (a) Axial T1WI MR shows fusiform isointensity on the posterior wall of the left eyeball; (b) axial T2WI MR shows homogenous hyperintensity; (c) oblique-sagittal T1 Contrast MR demonstrates homogenous strong enhancement
6.2.4 Conclusions
Ultrasound with the convenient and economic advantages is the first choice for this disease.It is difficult for CT to differentiate from other lesions such as choroid melanoma and metastases.MRI can clearly show the properties of the lesion and typical imaging characteristics.
6.3 Choroidal Osteoma
6.3.1 Pathology
- 1.
Ophthalmoscope shows a white, elliptic, slightly elevated tumor, the uneven pigmentation in cluster is seen on the surface.
- 2.
A benign tumor composed of mature bone tissue is usually flat or lenticular lens in appearance.
6.3.2 Imaging Examination Recommendations
- 1.
CT is the first choice of examination because of higher sensitivity to bone tissue.
- 2.
US becomes an important auxiliary examination means due to the simple, convenient advantages.
- 3.
MRI is mainly used for those cases with the secondary retinal detachment.
6.3.3 Imaging Findings
- 1.
CT findings: The lesion may occur in unilateral or bilateral eyeballs, a punctate, stripped, and curved high density located in the posterior wall of the eyeball (Fig. 6.5)
Fig. 6.5
(a) Axial soft tissue window CT shows punctate and stripped hyperdensity in posterior walls of bilateral eyeballs; (b) coronal bone window CT reveals curved high density
6.3.4 Conclusions
The confirmed diagnosis of choroidal osteoma can be made according to the characteristic CT manifestations.
Because of the low sensitivity to calcification and bone tissue, MRI is usually performed as a supplementary examination (Munteanu et al. 2008).
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