Objective To explore the relationship between the establishment of collateral circulation caused by iliac vein compression syndrom(IVCS) and the deep venous thrombosis (DVT). Methods Different types of ideal collateral circulation models and IVCS patient-specific models were numerically simulated using computational fluid dynamics (CFD) in combination with the blood stasis model. The relationship between blood retention and collateral types and cross-sectional area was studied, and the relationship with thrombosis was explored. Results Wall shear stress (WSS) at the distal end part of each ideal model was 0.3 Pa. After four cardiac cycles, the residual blood stayed at the stenosis and the distal end part for the lumbar ascending and pelvic type models, the old blood volume fraction (OBVF) varied with collateral cross-sectional areas, ranging from 5%-90% and 70%-80%, respectively. The OBVF of the coexistence model was above 80%. The WSS at the distal end part of the patient-specific model was 0.9 Pa, and the OBVF at the distal end part was 51.5%. Conclusions The stenosis and the distal end part are most prone to blood stasis, and closely related with DVT. The larger the collateral cross-sectional area, the more serious the blood stagnation. Blood stagnation of the coexistence model is higher compared with the model with lumbar ascending type and pelvic type.

The aim of this study was to synthesize and evaluate the necrosis avidity of MRI contrast agent based on rhein and linked by ether. The novel ligand 10-{［6-(1, 8-dihydroxyanthraquinone-3-carboxamido)ethoxyethyl］amino}carbonylmethyl-1, 4, 7, 10-tetraazacyclododecan-1, 4, 7-triacetic acid(DO3A-Ether-Rhein, E1)was synthesized by two steps of acylation and deprotection reaction. The paramagnetic gadolinium 10-{［6-(1, 8-dihydroxyanthraquinone-3-carboxamido)ethoxyethyl］amino}carbonylmethyl-1, 4, 7, 10-tetraazacyclododecan-1, 4, 7-triacetic acid(Gd-DO3A-Ether-Rhein, GdE1)was obtained by coordination of Gd3+ with the above ligand. We examined the necrotic avidity of GdE1 in human hepatocellular carcinoma HepG2 cell necrosis induced by hyperthermia in vitro and in rat model with muscular necrosis induced by microwave ablation in vivo by MRI. The MRI was implemented before administration of GdE1 and during 0-9 h after administration of GdE1(0. 1 mmol/kg), and Gd-DOTA(gadolinium 1, 4, 7, 10-tetraacetic acid-1, 4, 7, 10-tetraazacyclo dodecane)was used as control. The signal intensity of necrotic cells(4 369±70)was significantly higher than that of normal cells(2 555±84)(P< 0. 05). Similarly, the contrast ratio between necrotic and normal muscle at 3 h after administration of GdE1(2. 00±0. 12)was remarkblely higher than that at 0 h after administration of GdE1(1. 27±0. 03)(P< 0. 05). Therefore, GdE1 presents good necrosis affinity and has the potential to be used in the diagnosis of necrosis-related diseases.