To evaluate the clinical value of color Doppler ultrasound(CDUS) combined with vascular enhancement technology(VET) in diagnosis of iliac vein compression syndrome(IVCS).

From Jan 2016 to Oct 2018, 252 patients with the lower extremities chronic venous diseases(CVD) were selected in the Second Hospital of Hebei Medical University. The ipsilateral iliac veins of the affected limbs were examined by CDUS, VET and the combined diagnosis of IVCS before X-Ray venography(XRV). Iliac vein diameter stenosis ratio(DSR)>50% in transverse section was the criterion of ultrasound diagnosis of IVCS. The stenosis site of iliac vein and indirect signs of IVCS, such as presence of collateral circulation and the retrograde flow of internal iliac vein were recorded. The cases, which had the same results in CDUS, VET and both and XRV, were divided into IVCS group and non-IVCS group. The results of XRV were taken as the gold standard, the diagnostic efficiency of the above 3 methods in diagnosis of IVCS was calculated. The cases identically diagnosed by the most effective ultrasonic method and XRV were divided into DVT group and non-DVT group according to the deep vein thrombosis in lower limbs. In the non-DVT group, there were five groups of C2-C6 on the basis of the CEAP clinical grades of CVD in lower extremity. The relationship between IVCS and different CEAP clinical grades were analyzed. The locations of common iliac vein stenosis and collateral circulation formation and internal iliac vein reverse flow were evaluated for the diagnosis of the IVCS.

①XRV diagnosis of IVCS was used as the gold standard. Compared with CDUS and VET alone, the sensitivity and specificity of CDUS combined with VET was the highest(all P<0.05). ②The distribution of DVT and non-DVT was significantly different in IVCS group and non-IVCS group diagnosed by the CDUS combined with VET(χ²=145.0, P<0.001). ③In the non-DVT group, statistically significant differences of grades C3 and C5 were found between IVCS group and non-IVCS group(allP<0.05), while the differences of grades C2, C4 and C6 were non-significant(allP>0.05). ④For the proportion of the iliac vein stenosis sites, the prevalence of the primary section of left common iliac vein was much higher than those of the primary section of right common iliac vein and the middle-distal sections of bilateral common iliac veins(allP<0.05). There was no statistical difference between the middle-distal section of bilateral common iliac veins, and nor was bilateral junction area between external iliac vein and common femoral vein(allP>0.05). ⑤In IVCS group, which had the same results of CDUS combined with VET and XRV, there were statistical differences in the positive rate of collateral circulation and the retrograde flow of internal iliac vein(χ²=6.717, P=0.010), and the former is higher than the latter.

CDUS combined with VET has a higher diagnostic efficiency for IVCS than VET or CDUS alone. The presence of IVCS is closely related to DVT of lower extremities, but not related to clinical class of CEAP. The most common site of IVCS is the initial segment of the left common iliac vein. The presence of collateral circulation can be used as indirect indicators for the diagnosis of IVCS.

Ultrasonography, Doppler, color; Vascular enhancement technology; Iliac vein compression syndrome