Sunday, 15 January 2017

Orbital Calcifications

Case: 1
This is a 50-year-old man who underwent CT for headache.
Calcification of the trochlea
Calcification of the trochlea
CT demonstrates punctuate calcification in the anterior, medial and superior corner of the orbit.

Calcification of the Trochlea

Clinical presentation: Incidental finding.
Imaging findings: CT demonstrates punctuate calcification in the anterior, medial and superior corner of the orbit. The location is important not to be mistaken as a high-density foreign body.
Unilateral / bilateral symmetric.

The trochlea is a cartilaginous structure with a synoviumlined sheath that permits unimpeded movement of the superior oblique muscle. The tendon of the superior oblique muscle passes through the trochlea before it inserts along the supero-lateral portion of the globe. Calcification of the trochlea is often seen in elderly patients (25-30% in persons over 50 years old) and considered as degenerative change without clinical significance.
However, if the patient is younger than 40 years of age, there is a statistically significant correlation with diabetes and these findings should prompt an endocrine evaluation.
Other less common causes of trochlear calcification are Brown’s syndrome, traumatic and postsurgical changes.

Case 2:
This is a 16-year-old adolescent who presented with slowly progressive vision loss in the left eye.
Choroidal osteoma
CT demonstrates a plaque-like calcification in the posterior pole of the affected eye.

Choroidal Osteoma

Clinical presentation: new onset of blurry, distorted vision.
Imaging findings: CT demonstrates a plaque-like calcification in the posterior pole of the affected eye.

Choroidal osteomas are rare, benign, ossifying, choroidal tumors of unknown etiology. Histopathologic evaluation reveals mature bone with marrow space containing loose fibrovascular tissue. They occur predominantly in young females (90%) without a history of systemic or ocular disease, and are usually unilateral (75%). On ophthalmologic examination, they appear as yellow-white to orange-red plaques and are generally located in the macula or juxtapapillary region around the optic disc extending toward the macula. Variability in color occurs secondary to thinning, depigmentation, and hyperplasia of the overlaying retinal pigment epithelium.
They are typically oval in shape with well-defined scalloped margins. They may display progressive growth patterns, although regression in size has also been reported.

Complications include choroidal neovascularization (CNV), which can result in vision loss and subretinal hemorrhage. Retinal detachment is also common.
Ultrasound and CT are of particular value in diagnosing choroidal osteoma.
With B-mode sonography, choroidal osteoma shows increased echogenicity posteriorly within
the globe, with posterior acoustic shadowing, creating the “pseudo-optic nerve appearance.” On CT, choroidal osteomas are flat calcified lesions, less than 2 mm in thickness, within the posterior pole of the globe. They are typically located in the juxtapapillary region, and typically do not involve the center of the optic disc, which aids in differentiation from optic drusen.
Given their benign nature, choroidal osteomas are typically followed clinically. Identification of complications, particularly choroidal neovascularization, warrants treatment
given the risk of vision loss.
DD:
• Optic drusen.
• Choroidal metastases:
• Choroidal hemangioma.
• Hyaline plaque.

Case 3:
This is a 65-year-old man who underwent CT for headache.
Hyaline plaque
CT demonstrates punctuate calcifications on the surface of the globe at the 3 and 9 o’clock location

Scleral Calcification: Hyaline Plaque

Clinical presentation : Incidental finding.
Imaging findings: CT demonstrates punctuate calcifications on the surface of the globe at the 3 and 9 o’clock location and are usually bilateral. Common areas of degenerative hyaline plaque formation are at the insertions of the medial and lateral rectus muscles. It is thought that these calcific deposits are of no clinical significance. These patients are usually older than 80 years of age; however, this condition can be seen earlier in patients with a history of cataract surgery or other infectious or inflammatory conditions.
On CT, there is a clearly defined focal high-density lesion at the insertions of the medial and lateral rectus muscle, again typically at 3 and 9 o’clock locations. These lesions
are difficult to visualize on MRI, although a signal-void can occasionally be identified.
Metallic or glass foreign bodies can show a similar appearance. Therefore, careful evaluation of the location of high-density lesions is critical. Hyaline plaques are seen in the typical surface locations in elderly patients, and should be easily distinguished from high-density foreign bodies.

DD:
Foreign body.
Optic drusen seen in the surface of the optic disc, which become calcified with advancing
age. However, drusen can be seen in relatively young patients.
Choroidal osteoma is a benign, ossifying, choroidal tumor of unknown etiology. It occurs predominantly in young females with no history of systemic or ocular disease, and usually unilateral.

Case 4: 
This is a 68-year-old man who underwent CT for headache.
Optic drusen

CT demonstrates a punctuate calcification at the optic disc.

Drusen

Clinical presentation : Incidental finding.
Imaging findings: CT demonstrates a punctuate calcification at the optic disc.

Drusen is caused by the accumulation of mucopolysaccharides and proteinaceous material on the surface of the optic disc, which can become calcified with advancing age.
There is an inherited form with an autosomal trait with irregular penetrate.

Drusens are commonly asymptomatic and incidentally found on CT performed for other reasons. These lesions can cause visual field defects and rarely can also lead to deficits in central acuity. Approximately 75% of drusen are bilateral. They are usually seen in elderly patients, and are rare in children. They are also believed to cause headaches. The diagnosis of drusen is simplified when these
Lesions lie on the surface of the optic disk, where they can be easily detected on fundoscopic examination. When drusen lie deep within the tissue of the optic nerve, however, the typical fundoscopic appearance may not be evident. When these small lesions develop within the nerve tissue, they can lead to elevation of the disc, which can be diagnosed as papilledema
(pseudopapilledema). Under these circumstances, CT or MRI can be performed to look for conditions that may cause elevated intracranial pressure.

DD:
• Choroidal osteoma: Choroidal osteoma is a benign, ossifying, choroidal tumor of unknown etiology. It occurs predominantly in young females with no history of systemic or ocular disease, and usually unilateral.
• Choroidal hemangioma: Choroidal hemangioma is a benign vascular tumor with phebolith.
• Choroidal metastases: Metastatic choroidal tumors are not rare, although they are not very often appreciated clinically. Most common primary sites are breasts and lungs.
• Hyaline plaque: This is degenerative change and seen in elderly populations, usually more than 80 years old. Focal calcification is seen at the insertion of medial and lateral rectus muscles.

Case 5: 
30 y o male with history of firework trauma, foreign body. Now reduced vision.
Foreign body
CT demonstrates hyper dense foreign body in left orbital pre septal space.

Imaging findings: Most typical or important is nothing typical.  Often unilateral , can be bilateral but never symmetric.
Clinical presentation : Often Symptomatic. History of trauma is most often present followed by reduced vision with or without pain.

1 comment:

Dr Ganesh Rajput said...

Sir, I had seen choroidal osteopathic case