ISNVD Abstract Book

TUESDAY – FEBRUARY 21, 2012 1:30pm-1:55pm
Flow characteristics in a study of 300 MS patients (E. Mark Haacke, USA)
Studies of venous flow of MS patients have been performed mostly with ultrasound imaging. Our recent work
using contrast enhanced MRA (CE-MRA), 2D time-of-flight MRV (TOF-MRV) and phase contrast MRI (PC-MRI)
has shown that the internal jugular vein (IJV) flow at the cervical 6 (C6) level is reduced for patients with
anatomically stenotic IJVs. In this work, we study the venous flow characteristics in MS patients. The study was
approved by local institutional review board. Three hundred (300) clinically definite MS patients signed
informed consent forms and participated in the study. Three-dimensional CE-MRA data were collected to
locate IJV stenoses by examination of the vasculature and multiple 2D TOF-MRV data with high in-plane
resolution was used to measure vessel cross-sectional area (CSA) to determine stenoses. Thresholds of 25mm 2
around the cervical 6 (C6) level and 12.5mm 2 around the C2 level were used to determine IJV stenosis. Based
on this stenosis assessment, all MS subjects were divided into 2 groups, non-stenotic (NST) and stenotic (ST).
Blood flow was measured with 2D PC-MRI imaging around C6 level perpendicular to the IJVs on a 3T Siemens
Magnetom Tim Trio with the following parameters: TR = 14.4ms, TE = 4.41ms, flip angle = 25 o , FOV =
256mm×256mm, in-plane resolution = 0.57mm×0.57mm, slice thickness = 4mm and maximum encoding
velocity (VENC) = 50cm/sec. Retrospective pulse gating was used and a total of 25 images were reconstructed
during one cardiac cycle. Vessel segmentation was achieved manually using our in-house MATLAB software.
Occasional aliasing in major vessels was mostly corrected by a simple phase unwrapping algorithm [2].
Statistical analysis was performed to compare the quantitative findings among the groups. Paired and unpaired
t-tests were performed as appropriate to evaluate the statistical significance of the differences. The flow images
from all subjects were inspected to insure good quality. Of the 300 subjects, the flow data from 22 cases were
deemed of bad quality and were not included in the study.
Of the remaining 278 subjects, 135 (48.6%) were determined to be in the NST group and 143 (51.4%) in the ST
group. There was no significant difference between the total arterial flow rates for the NST and ST groups
(16.4±2.6, 16.7±2.9, respectively; p=0.40). This finding indicate that the method was not biased toward any
group for flow measurement. On the venous side, the blood flow through the LIJV was found to be significantly
less than that of the RIJV (4.6 ± 2.1 vs. 7.0 ± 2.4mL/sec, respectively; p2/3), (34.1, 56.6) % were type II (1/3