OBJECTIVE
To study the possibility of the modern CT and MRI methods in diagnostics of the orbital venous varices (OVV), discover the special characteristics of these lesions concerning their hemodynamic and differential diagnosis with other orbital lesions.
MATERIAL AND METHODS
In the period from 2012 to 2019 ten patients with OVV were evaluated. Four of them were men, three — women and three — children (boys aged 7, 10, and 12 years). Age of the patients varied from 7 to 75 years old (mediana — 34).
CT was performed on 9 patients using low dose protocol with injecting the contrast in standard position (supine) and in the prone position. CT-angiography was performed on 3 patients and CT-perfusion — 5 patients which allowed the assessment of the blood supply and quantitative lesions hemodynamic by calculating blood flow (BFOVV), blood volume (BVOVV) and mean transit time (MTTOVV).
MRI with contrast injection and Fat Sat technology was performed on 9 patients, 3 of them were both in the supine and prone positions. 4 patients were evaluated by bolus MR-angiography (TRICKS).
RESULTS
The majority of the OVV was localized in the medial compartments and apex of the orbit. Left sided lesions were found in 6 cases, right — 3. One patient had both sided OVV. In one of the cases in 10-year-old child, we revealed malformation of the Galen vein associated with bilateral varicose enlargement of the intraorbital veins (secondary OVV).
In CT studies all of the lesions enhanced after the contrast injection. When the patients were study in the prone position, all lesions were enlarging; which lead to the diagnosis of OVV. CT-angiography (venous blood flow) proved vascular nature of the lesions. While studying the quantitative lesion hemodynamic by the CT perfusion technology, it was discovered, that OVV tend to have high blood volume (BVOVV=19.61±3.23(ml/100g) and high blood flow (BFOVV= 60.87±8.11) and the prolongation of mean transit time (MTTOVV=19.23±3.07). Normal parameters measured in white matter were CBVN=1.37±0.69(ml/100g), CBFN=38.4±4.31(ml/100g/min), MTTN=2.89±0.44s.
In MRI studies all the lesions had iso-hypointense MR-signal on T1- and hyperintense on T2-images. The pattern of contrast enhancement was inhomogeneous, however reaching homogeneity after some time. TRICKS MR-angiography was more sensitive than CT-angiography (venous phase). Moreover, the absence of radiation exposition was an additional advantage of the MR-venography.
CONCLUSION
Diagnosis of orbital vascular pathology requires an understanding of the classification of vascular lesions, the integration of the patient’s medical history with epidemiological data, as well as a through analysis of the results of instrumental diagnostic methods. CT or MRI, including scanning in the prone position, as well as minimally invasive CT- and MR-TRICKS-angiography and ophthalmological studies of the patient, determine a comprehensive approach to the diagnosis and selection of adequate treatment for orbital venous varices.
In the differential diagnosis of OVV with other neoplasms of the orbit, we recommend CT-perfusion study with determine the quantitative characteristics of its hemodynamics.
