© Pol J Radiol, 2011; 76(1): 59-62 Hartel M et al – Magnetic Resonance Venography of chronic cerebrospinal… Figure 3. T2FatSat; pathologic valve/stenosis in the junction of the left IJV with brachiocephalic vein. Figure 4. T2FatSat; slower flow in the IJV, as well as subclavian and brachiocephalic veins, on the left side. Figure 5. FIESTA and 2DTOF; the azygous vein is smaller than usually, with an abnormally low flow: breath-hold acquisition during Valsalva maneuver (the azygous vein should dilate and the mediastinum usually moves a little anteriorly). showed no such flow patterns. The pathologies mentioned were seen: on the right side in 6% of scanned MS patients, on the left side – 15%, on both sides with right-side pre- dominance – 22%, on both sides with left-side predomi- nance – 34%, bilaterally with no side predominance – 19%. In 17 cases (2%), a more pronounced pathology was seen: slower blood flow in IJVs, vertebral, subclavian and also in the left brachiocephalic veins. Moreover, in 42 cases (5%), a decreased blood flow in the AV was detected (Table 1). Discussion The most common causes of a slower blood flow in CCSVI patients are the obstructed or malfunctioning valves (Figure 3). In our opinion, the main purpose of MRV is not to visualize such a valve, but to demonstrate the influence of such pathological structures on flow characteristics. In addition, MRV can demonstrate anatomical abnormalities (such as hypoplasia or agenesis of a vein) that may make endovascular treatment of CCSVI challenging or even impossible. The most common CCSVI pathology, namely the pathologic flow in the IJV, can be also detected with color Doppler sonography [21]. However, pathologic outflows or anatomical abnormalities in AV or brachiocephalic vein cannot be diagnosed by means of color Doppler sonogra- phy. Hence, MRV remains the only reliable diagnostic tool in case of these veins (Figures 4, 5). Importantly, a stan- dard MRV with gadolinium contrast enhancement, which 61