EM Haacke1,2, PhD, D Utriainen1, BS, S Sethi1, MS, W Feng2, PhD, JJ Hewett3, MD, M Arata3, MD 1MR Innovations, 2Wayne State University, 3Pacific Interventionalists
INTRODUCTION: Quantitative imaging of CCSVI using magnetic resonance imaging (MRI) provides an opportunity to study not just anatomical abnormalities1-8 but also the ability to quantify flow2,3,4,7,9. These two pieces of information may provide new biomarkers over and above those originally introduced by Zamboni et al using ultrasound. Specifically, recent MRI findings suggest that the total internal jugular vein (IJV) flow normalized to the total arterial inflow as measured from the carotids and vertebral arteries and the dominance of flow on one side of the neck may represent risk factors for developing MS2-4.
MATERIALS AND METHODS: A previous study of 323 MS subjects was compared with a new group of 145 MS subjects and 33 healthy controls. IJV structure was assessed for stenosis, atresia, and aplasia using a combination of 2D time of flight MR venography (TOF MRV) and 3D contrast enhanced MR angiography and venography (CE MRAV). The subjects were sub-grouped into stenotic (ST) and non-stenotic (NST) categories. Two dimensional phase contrast flow quantification (PC FQ) was used to quantify the flow through the vessels of the neck perpendicular to the IJV positioned between the sixth and seventh cervical vertebrae as well as the second and third cervical vertebrae. All data were processed using FlowQ (for flow quantification) and SPIN (signal processing in NMR, for anatomical assessment) software. IJV flow was normalized to the total arterial input. All data were collected on a Siemens 3T TRIO scanner.
RESULTS: For the 145 MS patients, 71 were categorized as NST and 74 as ST. IJV flow was normalized to arterial flow and plotted as C2 vs C6. A total of 22 (28.4%) of the ST MS, 1 (1.4%) of the NST MS, and 1 (3.0%) of the healthy controls fell below 50% at both levels. This agreed with our previous findings in which none of the 100 NST MS patients fell below 50% at both levels while 70 (31.4%) of the ST MS did.
Figure 1: Plots showing the total IJV flow (Fijv) normalized to the total arterial flow (Fta) at the C2 level vs. the C6 level for two separate samples. Legend: triangle=healthy control, open circle=NST MS, cross=ST MS. (A) Published data on 323 MS subjects, 223 ST and 100 NST 2. (B) A new group of 145 MS, 74 ST and 71 NST, and 33 healthy controls.
DISCUSSION AND CONCLUSION: Quantifying flow for studying CCSVI in MS is a critical part of evaluating what is abnormal in an MS patient. It is now clear that a significantly higher portion of the MS population shows low internal jugular vein flow compared to normal controls and that 2D PCFQ serves as a key biomarker for MS.
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