Subjects with vasculitis or any vascular malformations were excluded from the study. No invasive study was performed on the patients and controls, informed consent was obtained from all of the subjects and they were not charged for the evaluations. Demographic data of the patients, MS duration and organ system dysfunctions (including GI, urinary, memory, visual, motor, sensory, etc.) were also recorded

at the visit or by calling the patients in case they were not able to attend the clinics. The Kurtzke expanded disability status scale (EDSS) method was used to quantify disability of MS patients [10]. Measuring EDSS was done by one neurologist to decrease probable interpersonal errors. All of the studied subjects underwent color-coded sonographic evaluation of intracranial GSK2118436 [deep middle cerebral vein (DMCV)] and FG-4592 mouse extracranial [bilateral jugular] veins. For bilateral jugular veins assessment, a 6.0 MHz linear

probe and for intracranial veins, a 2.0 MHz phase array probe was used (MyLab™ 40, Esaote, Italy). Each subject underwent ultrasound evaluations twice. The first time was in supine position and then in upright (90°, sitting) position. Velocity of intra- and extracranial veins was recorded. The diameter of bilateral internal jugular veins was also measured using B mode imaging in horizontal plane. When measuring veins’ diameter, special attention was paid not to compress the veins by the probe. The mentioned indices were measured in patients and controls in supine and upright positions, on an identical point and the differences between these 2 measures were calculated.

Cerebrospinal venous return was also assessed in subjects while they were positioned on a tilt bed. The blood flow to the opposite of physiologic direction for more than 0.88 s in extracranial and more than 0.5 s in intracranial veins were considered as reflux in the subjects [11]. To decrease interpersonal measurement errors, one specialist performed all of the assessments. If there was a significant respiratory variation in the blood flow velocity and the diameter in the assessed Baf-A1 supplier veins within subjects, we asked the patient to hold his breath for a short time after a normal exhalation, and the assessments were performed in these breathless times. If there was a local narrowing in the vein, all of the available length of the vein was studied in sagittal plane for more accurate measurements. The vein diameter less than 0.4 cm2 in supine position was considered stenosis. The presence of 2 or more of the following criteria was known as CCSVI in studied patients: 1. A reflux in right or left internal jugular veins. The data were analyzed using SPSS software v.16 for windows. One sample K–S test was used to check the distribution of quantitative variables. To compare normally distributed variables between the 2 groups Independent Samples T-test was used and in skewed variables Mann–Whitney U test was performed. In qualitative data, chi-square test was used.