The Significance Of Guiding Interventional Thrombolysis Of Deep Vein Thrombosis Based On Magnetic Resonance Black-blood Thrombus Imaging Manifestation

ObjectiveTo investigate the feasibility of T1-weighted magnetic resonance thrombus imaging(BTI)for diagnosis of deep vein thrombosis(DVT)and preliminary evaluation of the prognosis of interventional thrombolytic therapy according to the imaging features of thrombus.Methods100 patients with acute DVT and accorded with the inclusion criteria were collected from interventional department of Panyu Central Hospital from September 2015 to February 2017.Informed consent was obtained from all patients.BTI and contrast enhanced MR venography(CE-MRV)were conducted to scan the entire lower limb from lower inferior vena cava to the distal part of the calf vein.The images of CE-MRV and BTI were loaded to a workstation and processed with Curve planar reformation(CPR)technique.Two experienced radiologists analyzed the diagnosis agreement of the CE-MRV and BTI in the diagnosis of the location and area of DVT.Using the consensus CE-MRV as reference,the sensitivity(SE),specificity(SP),positive and negative predictive values(PPV and NPV),and accuracy(ACC)of BTI for the diagnosis of thrombus were calculated.DVT at different periods showed different thrombus signal on magnetic resonance image.In order to quantify the thrombus signal changes during different stages,contrast-to-noise ratios(CNRs)between the thrombus and the muscle([SIthrombus-SImuscle]/σn)were calculated.catheter—directed thrombolysis(CDT)therapy were performed the day after MRI examination.Thrombolysis rates were measured after treatment.Pearson correlation was used to analyse the correlation between thrombolysis rate and CNR of thrombus、duration of the clinical symptoms、duration of thrombolysis、amount of thrombolysis、age.Using thrombolysis rate as dependent variable,CNR of thrombus、duration of the clinical symptoms、duration of thrombolysis、amount of thrombolysis、age as independent variables,multiple linear regression model were used to analyse the correlation between thrombolysis rate and CNR of thrombus、duration of the clinical symptoms、duration of thrombolysis、amount of thrombolysis、age.ResultsUsing the consensus CE-MRV as reference,the sensitivity(SE),specificity(SP),positive and negative predictive values(PPV and NPV),and accuracy(ACC)of BTI for thrombus diagnosis by two docters were 98.26%,99.50%,99.03%,99.09%,99.07%和 97.11%,98.98%,98.05%,98.48%,98.33%separately.The average CNR between the thrombus and the muscle on BTI image was 56.31±43.95.After thrombolysis,9 patients were treated with additional balloon dilatation or stent placement in the iliofemoral vein.Pearson correlation analysis showed that there was great correlation between thrombolysis rate and CNR of thrombus(r=-0.86;P<0.01).The lower the CNR,the better the thrombolysis effect.It indicated that thrombus on the BTI images appeared as isointense signals had a better thrombolysis effect.There were negnative correlation between thrombolysis rate and duration of the clinical symptoms、amount of thrombolysis(r=-0.430,P=0.00<0.05;r=-0.281,P=0.005<0.01).Multiple correlation analysis also showed that there was correlation between thrombolysis rate and CNR of thrombus(P<0.01).there was no correlation between thrombolysis rate and age、duration of the clinical symptoms、duration of thrombolysis、amount of thrombolysis、age.ConclusionBTI is an accuacry technique to diagnose the location and area of DVT.The isointense signals thrombus may be considered as an early acute stage with excellent thrombolysis effect.Therefore,It is expected to predict the effect of thrombolysis according the magnetic resonance imaging features of thrombus and guide the choice of clinical treatment.