ORIGINAL ARTICLES   

International Angiology 2000 December;19(4):319-25

Copyright © 2001 EDIZIONI MINERVA MEDICA

lingua: Inglese

Colour Doppler ultrasonography of the ophthalmic artery: flow parameters in normal subjects. The significance of the resistance index

Kouvidis G. K., Benos A., Kyriakopoulou G., Anastopoulos G., Triantafyllou D.

From the Radiology Department, 7th IKA Hospital, Athens, Greece * Lab of Hygiene, Medical Department, Aristotle University, Thessaloniki, Greece

Background. The aim of this study was to ­assess the flow char­ac­ter­is­tics in oph­thal­mic arter­ies and to ­detect their pos­sible rela­tion­ships to those in the com­mon and inter­nal carot­id arter­ies.
Methods. Sixty ­healthy sub­jects (age range 20-74 years) with nor­mal vas­cu­lar find­ings, strat­i­fied by age and sex were recruit­ed to the study. A ­colour Doppler ultra­sound exam­ina­tion of the neck arter­ies was per­formed, fol­lowed by a ­colour Doppler ultra­sound exam­ina­tion of the 120 oph­thal­mic arter­ies includ­ed. Peak sys­tol­ic veloc­ity, end dia­stol­ic veloc­ity and resis­tance index (RI) of the com­mon carot­id, inter­nal carot­id and oph­thal­mic arter­ies, as well as the inso­na­tion depth of the oph­thal­mic arter­ies were meas­ured.
Results. The mean val­ues (stan­dard devi­a­tion) of the meas­ured param­e­ters for the oph­thal­mic arter­ies were: inso­na­tion depth: 38.38 mm (2.60 mm), peak sys­tol­ic veloc­ity: 34.71 cm/sec (6.38 cm/sec), end dia­stol­ic veloc­ity: 7.95 cm/sec (1.70 cm/sec), resis­tive index: 0.77 (0.04). The resis­tance index of the oph­thal­mic arter­ies was, in all cases, great­er than that of the ipsi­lat­er­al com­mon carot­id ­artery which in turn, was great­er than that of the inter­nal carot­id. The value of the index in the oph­thal­mic arter­ies, when the cir­cu­la­tion is nor­mal in the extra- and intra­cra­ni­al arter­ies is rare­ly lower than 0.70.
Conclusions. When an inver­sion of the ratio ­between the resis­tance index of the oph­thal­mic ­artery and that of the com­mon carot­id or an index value lower than 0.70 in the oph­thal­mic ­artery is ­observed, fur­ther inves­ti­ga­tion is need­ed as this sit­u­a­tion can­not be con­sid­ered nor­mal. The resis­tance index seems to be the most reli­able param­e­ter for the esti­ma­tion of nor­mal cir­cu­la­tion in oph­thal­mic arter­ies.