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Orbital Lesions: Differentiating Vascular and Nonvascular Etiologic Factors

¹ Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, CT.
² Department of Radiology, SUNY Upstate Medical University, 750 E Adams St., Syracuse, NY 13210.

Received January 29, 2007; accepted after revision October 27, 2007.

 
Address correspondence to C. S. Poon (poonc{at}upstate.edu).

Abstract

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OBJECTIVE. Using a number of interesting cases, we illustrate how attention to vascular anatomic features and blood flow patterns can facilitate the diagnosis of an orbital lesion. True vascular lesions can be differentiated from nonvascular mimics, and normal variants of the orbital blood flow pattern can be differentiated from pathologic alterations.

CONCLUSION. Accuracy of radiologic diagnosis can be improved by an understanding of orbital vascular anatomy and blood flow patterns and with optimal use of imaging techniques.

Keywords: angiography • CT angiography • MRI • orbit • superior ophthalmic vein

Introduction

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Mass effect on the orbits can lead to clinical presentations such as proptosis, orbital pain, and diplopia. In most cases, the effect is caused by soft-tissue lesions. However, vascular lesions, either within the orbits or extraorbital, can alter the normal orbital blood flow pattern and lead to vascular engorgement and an orbital mass effect [1, 2]. More confusingly, soft-tissue lesions and vascular abnormalities can have similar imaging appearances, posing diagnostic difficulty for inexperienced radiologists. Differentiation of vascular and nonvascular lesions is important, because the difference can dictate completely different approaches to further evaluation and management. In most cases, differentiation can be accomplished with cross-sectional imaging. The vascular lesions can be further evaluated or managed with neurointerventional techniques.

Illustrative Cases

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A good understanding of orbital anatomy [3, 4] is essential to correct diagnosis. Soft-tissue masses, such as neurofibroma, can appear fusiform. When they are located close to normal vascular structures, these masses can simulate vascular abnormalities. Figures 1A, 1B, 1C, 1D, 1E, 1F, 1G, and 1H illustrates a case in which thrombosed varix was suspected on the basis of the clinical presentation and initial interpretation of an MRI study (Figs. 1A, 1B, 1C, and 1D). Orbital varix most often involves the superior ophthalmic vein. In the middle of its course, the superior ophthalmic vein is an intraconal structure. Careful review of MR images, however, shows the mass is extraconal and superior in relation to the levator palpebrae superioris and superior rectus muscles. In addition, the right superior ophthalmic vein is clearly identifiable on MR images. Apart from displacement by the mass, all the venous structures appear normal. The mass exhibits only mild peripheral enhancement, similar to that of the other orbital soft tissues. These findings make the presumptive diagnosis of thrombosed varix unlikely. The location suggests the mass may arise from the supraorbital nerve, leading to strong suspicion of neurofibroma or schwannoma.

View larger version (136K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 1A —28-year-old man with right proptosis. MRI findings were initially interpreted as thrombosed varix. Neurofibroma was confirmed at surgery and surgical pathologic examination. Axial T2-weighted MR image shows fusiform lesion with homogeneous hyperintensity.

View larger version (121K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 1B —28-year-old man with right proptosis. MRI findings were initially interpreted as thrombosed varix. Neurofibroma was confirmed at surgery and surgical pathologic examination. Axial gadolinium-enhanced T1-weighted MR image shows only minimal peripheral enhancement.

View larger version (107K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 1C —28-year-old man with right proptosis. MRI findings were initially interpreted as thrombosed varix. Neurofibroma was confirmed at surgery and surgical pathologic examination. Coronal gadolinium-enhanced T1-weighted MR image with fat suppression shows both superior ophthalmic veins (arrows) are of normal caliber. M = mass.

View larger version (111K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 1D —28-year-old man with right proptosis. MRI findings were initially interpreted as thrombosed varix. Neurofibroma was confirmed at surgery and surgical pathologic examination. Sagittal gadolinium-enhanced T1-weighted MR image with fat suppression shows mass (M) is clearly extraconal.

View larger version (103K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 1E —28-year-old man with right proptosis. MRI findings were initially interpreted as thrombosed varix. Neurofibroma was confirmed at surgery and surgical pathologic examination. Contrast-enhanced axial CT scan shows no change with Valsalva maneuver and lack of enhancement make vascular lesion unlikely. E is cranial to F. M = mass.

View larger version (99K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 1F —28-year-old man with right proptosis. MRI findings were initially interpreted as thrombosed varix. Neurofibroma was confirmed at surgery and surgical pathologic examination. Contrast-enhanced axial CT scan shows no change with Valsalva maneuver and lack of enhancement make vascular lesion unlikely. E is cranial to F. M = mass.

View larger version (92K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 1G —28-year-old man with right proptosis. MRI findings were initially interpreted as thrombosed varix. Neurofibroma was confirmed at surgery and surgical pathologic examination. Coronal reformatted image shows superior ophthalmic veins (arrows). M = mass.

View larger version (69K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 1H —28-year-old man with right proptosis. MRI findings were initially interpreted as thrombosed varix. Neurofibroma was confirmed at surgery and surgical pathologic examination. Sagittal reformatted image obtained with bone window shows smooth erosion of orbital roof (arrow). M = mass.

When vascular lesions are suspected, CT angiography can be helpful for directing further evaluation and management [5–7]. In the case in Figures 2A, 2B, 2C, 2D, and 2E, initial suspicion of carotid–cavernous fistula by the clinician prompted further evaluation with CT angiography. On CT angiograms and other cross-sectional images, the appearance of carotid–cavernous fistula is secondary to arterialization of blood flow in the cavernous sinus, the ophthalmic veins, and other venous structures in communication with the cavernous sinus. This condition leads to engorgement or bulging of the cavernous sinus and dilation of connected venous structures. In the less common cases of low-flow fistula and late-stage fistula in which the superior ophthalmic vein is stenosed or thrombosed, these imaging features may be less evident. However, the absence of all of these imaging findings in this case made the possibility of carotid–cavernous fistula un likely, practically obviating conventional angiography. The CT angiographic and MRI findings pointed toward diffuse infiltrative disease rather than a vascular disorder. Given the clinical history of lung carcinoma, a presumptive diagnosis of orbital metastasis was made.

View larger version (103K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 2A —73-year-old man with history of lung cancer who presented with chemosis of right eye. Clinician had suspected carotid–cavernous fistula. CT angiogram shows superior ophthalmic veins and ophthalmic arteries are within normal limits. Cavernous sinuses (arrows, A) are bilaterally normal and symmetric. No other dilated vascular structures are evident. These findings make carotid–cavernous fistula and arteriovenous malformation unlikely. Subtle scleral thickening and infiltration of intraconal fat are evident.

View larger version (98K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 2B —73-year-old man with history of lung cancer who presented with chemosis of right eye. Clinician had suspected carotid–cavernous fistula. CT angiogram shows superior ophthalmic veins and ophthalmic arteries are within normal limits. Cavernous sinuses (arrows, A) are bilaterally normal and symmetric. No other dilated vascular structures are evident. These findings make carotid–cavernous fistula and arteriovenous malformation unlikely. Subtle scleral thickening and infiltration of intraconal fat are evident.

View larger version (131K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 2C —73-year-old man with history of lung cancer who presented with chemosis of right eye. Clinician had suspected carotid–cavernous fistula. Gadolinium-enhanced T1-weighted MR image with fat suppression shows superior ophthalmic veins appear normal bilaterally. Right orbit exhibits proptosis. Diffuse enlargement of all right extraocular muscles is evident, but tendon insertions are spared. Subtle enhancement is present within intraconal fat. Enhancement along right optic nerve sheath extends to orbital apex (long arrow). Subtle thickening of sclera with mild nodularity (short arrow, C) is evident.

View larger version (141K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 2D —73-year-old man with history of lung cancer who presented with chemosis of right eye. Clinician had suspected carotid–cavernous fistula. Gadolinium-enhanced T1-weighted MR image with fat suppression shows superior ophthalmic veins appear normal bilaterally. Right orbit exhibits proptosis. Diffuse enlargement of all right extraocular muscles is evident, but tendon insertions are spared. Subtle enhancement is present within intraconal fat. Enhancement along right optic nerve sheath extends to orbital apex (long arrow). Subtle thickening of sclera with mild nodularity (short arrow, C) is evident.

View larger version (86K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 2E —73-year-old man with history of lung cancer who presented with chemosis of right eye. Clinician had suspected carotid–cavernous fistula. Gadolinium-enhanced T1-weighted MR image with fat suppression shows soft-tissue stranding and enhancement in right orbital fat. All extraocular muscles are enlarged and enhanced. Contrast findings to those in Figures 3A, 3B, 3C, and 3D.

View larger version (84K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 3A —21-year-old man who sustained head trauma 5 months previously presenting with proptosis in left eye secondary to direct carotid–cavernous fistula. Correlation between CT angiographic and conventional angiographic findings is excellent. Unenhanced CT scan shows dilated left superior ophthalmic vein (SOV) and asymmetric engorgement of left cavernous sinus (arrow).

View larger version (111K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 3B —21-year-old man who sustained head trauma 5 months previously presenting with proptosis in left eye secondary to direct carotid–cavernous fistula. Correlation between CT angiographic and conventional angiographic findings is excellent. CT angiograms from superior to inferior planes show left proptosis. Left superior ophthalmic vein (SOV) is markedly dilated throughout its course. Left facial vein (FV) and angular veins (arrow, C) that communicate with left superior ophthalmic vein are dilated. Engorgement of left cavernous sinus is evident. OA = ophthalmic artery.

View larger version (98K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 3C —21-year-old man who sustained head trauma 5 months previously presenting with proptosis in left eye secondary to direct carotid–cavernous fistula. Correlation between CT angiographic and conventional angiographic findings is excellent. CT angiograms from superior to inferior planes show left proptosis. Left superior ophthalmic vein (SOV) is markedly dilated throughout its course. Left facial vein (FV) and angular veins (arrow, C) that communicate with left superior ophthalmic vein are dilated. Engorgement of left cavernous sinus is evident. OA = ophthalmic artery.

View larger version (153K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 3D —21-year-old man who sustained head trauma 5 months previously presenting with proptosis in left eye secondary to direct carotid–cavernous fistula. Correlation between CT angiographic and conventional angiographic findings is excellent. Midarterial phase left common carotid arteriogram in lateral projection shows prominent cavernous sinus (arrow) with immediate retrograde filling of superior ophthalmic vein. Retrograde filling in angular vein accounts for venous dilatation at nasal bridge and left face, as in B and C.

View larger version (110K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 4A —51-year-old man with progressive visual loss in right eye over 18 months. CT angiograms show enhancing lesion at right aspect of suprasellar cistern (arrow). Initial interpretation was aneurysm. More careful examination revealed lesion has elongated shape and extends to right orbital apex. Lesion contains fine linear enhancing structures indicative of small vessels, making diagnosis of arteriovenous malformation or hypervascular mass more likely. Findings were confirmed on MRI and MR angiography. A is cranial to B.

View larger version (142K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 4B —51-year-old man with progressive visual loss in right eye over 18 months. CT angiograms show enhancing lesion at right aspect of suprasellar cistern (arrow). Initial interpretation was aneurysm. More careful examination revealed lesion has elongated shape and extends to right orbital apex. Lesion contains fine linear enhancing structures indicative of small vessels, making diagnosis of arteriovenous malformation or hypervascular mass more likely. Findings were confirmed on MRI and MR angiography. A is cranial to B.

View larger version (127K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 4C —51-year-old man with progressive visual loss in right eye over 18 months. T2-weighted MR image shows lesion (arrows) contains serpiginous flow voids and extends from right suprasellar cistern along proximal ophthalmic artery to right orbital apex.

View larger version (112K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 4D —51-year-old man with progressive visual loss in right eye over 18 months. Gadolinium-enhanced T1-weighted MR image with fat suppression shows lesion has strong serpiginous enhancement (arrow). Right superior ophthalmic vein (not shown) was slightly larger than left, probably because of increased blood flow.

View larger version (90K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 4E —51-year-old man with progressive visual loss in right eye over 18 months. MR angiogram shows vascular lesion (arrow) arising at origin of right ophthalmic artery and extending to right orbital apex along ophthalmic artery. High signal intensity of lesion suggests it receives arterial supply from circle of Willis or its major branches.

View larger version (151K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 4F —51-year-old man with progressive visual loss in right eye over 18 months. Right internal carotid arteriogram (lateral projection) confirms diagnosis of arteriovenous malformation (AVM). Lesion (arrows) arises at origin of ophthalmic artery and extends to orbital apex. Venous drainage through cavernous sinus and petrosal sinuses is evident. Vascular blush supplied from distal ophthalmic artery is present at anterior orbit. This finding is secondary to hyperemia or secondary nidus.

View larger version (75K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 5A —30-day-old girl with right orbital mass. Axial T2-weighted MR image shows hyperintense extraconal mass (H) situated primarily in lateral and anterior aspects of right orbit. Mass contains multiple small flow voids and hypointense septa.

View larger version (70K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 5B —30-day-old girl with right orbital mass. Gadolinium-enhanced T1-weighted MR image with fat-suppression shows intense homogeneous enhancement. Prominent vessel (arrow) is evident on superior aspect of mass.

View larger version (60K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 5C —30-day-old girl with right orbital mass. MR angiogram shows prominent vessel (arrow), presence of which favors diagnosis of capillary hemangioma as opposed to venolymphatic malformation.

View larger version (97K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 6A —53-year-old woman with right-sided diplopia. Conventional angiographic findings suggested lesion represented presence of normal variant in venous drainage of brain. Drainage of supratentorial venous blood into anterior cavernous sinus caused transient venous overflow in anterior cavernous sinus and reflux of venous blood into proximal superior and inferior ophthalmic veins. Coronal fat-suppressed gadolinium-enhanced T1-weighted MR image shows bilateral dilatation of superior ophthalmic veins. Right inferior ophthalmic vein is patulous. Findings suggest presence of vascular lesion such as carotid cavernous fistula.

View larger version (101K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 6B —53-year-old woman with right-sided diplopia. Conventional angiographic findings suggested lesion represented presence of normal variant in venous drainage of brain. Drainage of supratentorial venous blood into anterior cavernous sinus caused transient venous overflow in anterior cavernous sinus and reflux of venous blood into proximal superior and inferior ophthalmic veins. Coronal T2-weighted MR image clearly shows symmetric and normal cavernous sinuses (arrows) on both sides.

View larger version (157K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 6C —53-year-old woman with right-sided diplopia. Conventional angiographic findings suggested lesion represented presence of normal variant in venous drainage of brain. Drainage of supratentorial venous blood into anterior cavernous sinus caused transient venous overflow in anterior cavernous sinus and reflux of venous blood into proximal superior and inferior ophthalmic veins. Right internal carotid arteriogram in early venous phase shows superficial middle cerebral vein drains into sphenoparietal sinus and then into anterior cavernous sinus. Proximal superior ophthalmic vein is faintly evident. Cavernous sinus drains into sigmoid sinus and transverse sinus through petrosal sinuses.

View larger version (138K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 6D —53-year-old woman with right-sided diplopia. Conventional angiographic findings suggested lesion represented presence of normal variant in venous drainage of brain. Drainage of supratentorial venous blood into anterior cavernous sinus caused transient venous overflow in anterior cavernous sinus and reflux of venous blood into proximal superior and inferior ophthalmic veins. Magnified later venous phase carotid arteriogram shows patulous proximal portion of superior ophthalmic vein, but no filling of distal superior ophthalmic vein or facial veins or evidence of arteriovenous shunting. Contrast findings to carotid–cavernous fistula in Figures 3A, 3B, 3C, and 3D.

Summary

Top Abstract Introduction Illustrative Cases Summary References

 
Orbital symptoms and signs are nonspecific. They can be associated with intraorbital or extraorbital disease and can have a vascular or nonvascular cause. In rare instances, even variants of orbital blood flow patterns can cause orbital signs and symptoms. Understanding orbital anatomy and vascular blood flow patterns and optimal use of imaging techniques facilitate confident evaluation of the fine structures of the orbit and improve diagnostic accuracy. The key imaging features are summarized in Table 1.

References

Top Abstract Introduction Illustrative Cases Summary References

 

1. Rootman J. Vascular malformations of the orbit: hemodynamic concepts. Orbit 2003;22 : 103-120[CrossRef][Medline]
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8. Bilaniuk LT. Vascular lesions of the orbit in children. Neuroimaging Clin N Am 2005;15 : 107-120[CrossRef][Medline]
9. Forbes G. Vascular lesions of the orbit. Neuroimaging Clin North Am 1996; 6:113 -122
10. Rootman J. Distribution and differential diagnosis of orbital disease. In: Diseases of the orbit: a multidisciplinary approach, 2nd ed. Philadelphia, PA: Lippincott, Williams & Wilkins, 2003: 52-84
11. Katz SE, Rootman J, Vangveeravong S, et al. Combined venous lymphatic malformations of the orbit (so-called lymphangiomas): association with noncontiguous intracranial vascular anomalies. Ophthalmology 1998;105 : 176-184[CrossRef][Medline]
12. Selva D, Fraco DS, Bonavoconta G, et al. Orbital venous-lymphatic malformations (lymph angiomas) mimicking cavernous hemangiomas. Am J Ophthalmol 2001; 131:364 -370[CrossRef][Medline]
13. Lirng JF, Fuh JL, Wu ZA, et al. Diameter of the superior ophthalmic vein in relation to intracranial pressure. Am J Neuroradiol 2003; 24:700 -703[Abstract/Free Full Text]
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This Article Abstract Figures Only Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Poon, C. S. Articles by Johnson, M. H. Search for Related Content PubMed PubMed Citation Articles by Poon, C. S. Articles by Johnson, M. H. Social Bookmarking                      What's this? Hotlight (NEW!) What's Hotlight?