Colour Doppler imaging of the orbital vasculature in Graves' disease with computed tomographic correlation

Aims-To evaluate alterations in orbital blood flow parameters and their correlations with extraocular muscle enlargement, proptosis, and intraocular pressure in patients with Graves' disease. Methods-In this multicentre study blood flow parameters in the ophthalmic artery, superior ophthalmic vein, central retinal artery and vein were determined by colour Doppler imaging in 111 patients with Graves' disease in two groups (A and B) and 46 normal control subjects. Group A consisted of 42 patients with Graves' disease without ophthalmopathy; group B of 69 patients with Graves' disease with ophthalmopathy as detected by orbital computed tomographic scanning. Results-Peak systolic and end diastolic velocities in the ophthalmic artery, peak systolic velocity in the central retinal artery, and maximal and minimal velocities in the central retinal vein in patients in group B were statistically significantly higher than those in group A and the normal controls, whereas maximal and minimal velocities in the superior ophthalmic vein in patients in group B were statistically significantly lower than those in group A and the control subjects. Peak systolic and end diastolic velocities in the ophthalmic artery, peak systolic velocity in the central retinal artery, and maximal and minimal velocities in the central retinal vein also correlated with the sum of all extraocular muscle diameters in group B (r greater than or equal to 0.31, p less than or equal to 0.021). Blood flow parameters had no consistent correlation with proptosis or intraocular pressure (p>0.05). No statistically significant difference was found in resistivity indices between the groups (p>0.05). Reversed blood flow was noted in nine (13%) superior ophthalmic veins in group B. Conclusion-Orbital blood flow velocities are altered in patients with Graves' ophthalmopathy and may be detected by colour Doppler imaging. Some of these changes also correlate with the enlargement of extraocular muscles. The increased blood flow velocities in arteries may be secondary to orbital inflammation.