| Objectives:To diagnose the lesions of the hepatic veins (HVs) and the inferior venous cava (IVCs) as well as to evaluate the blood-draining vessels of the obstructed HVs by using ultrasonography combined with magnetic resonance imaging (MRI) in patients with Budd-Chiari syndrome (BCS). The blood-draining vessels in this study were mainly the accessory hepatic veins (AHVs) (including the caudate lobe veins and the inferior right hapetic veins) and the patent HVs. Effective blood drainage criterion from the obstructed HVs would be preliminarily established by measuring and calculating the hemodynamic index obtained from ultrasonographic examination.Materials and methods:This study was based on data obtained with ultrasonography and MRI between January 2012 and November 2015 from 52 inpatients with chronic BCS, including 24 male (age range,29-61 y; mean age,52.00±9.66 y) and 28 female (age range,29-63 y; mean age,47.56±10.13 y) patients. The diagnosis of BCS based on the obstructions of HVs and IVCs on ultrasonogram and MRI, which was finally confirmed by digital subtraction angiography (DSA). In all patients, the time from the first clinical symptom to diagnosis ranged from 2 weeks to 24 years. The main clinical symptoms were right upper abdominal distention, abdominal wall varicosis, edema or (and) varicosis of both lower extremities. Patients in whom BCS was secondary to oncothlipsis or malignant cell embolism were excluded.Ultrasonography was performed using a Logiq E9 (GE Healthcare, Waukesha, WI, USA), with multifrequency (2.0-6 MHz) convex transducers. All patients fasted more than 8 hours before the examination and were scanned in the supine or left recumbent position. Patients who can’t be displayed clearly with heavy intestinal gas should use sugar-refining the night before ultrasound examination.All MR examinations were performed with a 3.0-T system (Magnetom Verio, Siemens, Germany). An eight-channel abdominal phased-array surface coil were used for signal reception. The abdominal transverse conventional sequences, pre-contrast three-dimensional fat-saturated T1-weighted sequence (volume interpolated body examination, Siemens, Germany) and coronal mask scan were initially performed. Transverse contrast-enhanced 3D-volume-interpolated body examination (3D-VIBE TIWI) sequence was given during suspended respiration at 20s after contrast injection, followed by a wide range of three dimensional contrast-enhanced scan for venous vessels. Patients was covered from hilar to iliac crest level, front of the level of vertebral trailing edge and behind of abdominal wall. FL3D imaging was performed in the coronal plane with a at 55s,90s and 120s after contrast injection, allowing enough interval for breath. The scanning condition is the same as the previous mask. The technical parameters were as follows:TR,2.95ms; TE,1.07ms; flip angle,15degrees; FOV 450×450mm; matrix,256×128; NEX= 3. Gd-DTPA or Gd-EOB-DTPA (0.1mmol/kg) was injected intravenously at a rate of 3.0 ml/s by a power injector (high-pressure injector:XD 2000 CT/MR), followed by a 20-mL saline flush, and the maximum dose not more than 20 g.Subtracting the image of pre-contrast from the original data of images at venous phase (55s,90s and 120s) through a commercially available software workstation system (Syngo Multimodality workplace, Siemens, Germany), the background signal could be reduced, and the small vessels could be displayed better. Performing the MIP (maximum intensity projection, MIP) and MRP (multiplanar reformation, MPR) separately to the subtracted images, can observe the display of venous system and collateral circulation, anatomical structure and space adjacent relationship between them from all angel. What is more, the display of a vessel could be better through rebuilding the small range of interest (ROI) again and again, getting rid of the overlapped vessels images partly, for example the vessel of portal venous trunk and collateral circulation.MR diagnosis was made by two radiologists in senior positions without previously knowing the results of other images and when the diagnosis of them agreeded with each other, the results were considered valid. Ultrasonic diagnosis was made by an ultrasound specialist with about 20-year experience. First, the HVs and IVCs were observed with ultrasonography in search of vascular lesions and intra-or extra-hepatic collateral circulations. In the presence of HV and IVC obstructions or collateral circulations, the vascular obstructions and the collateral circulations were classified, and meanwhile, the number and site of outlets of draining veins were carefully observed, the diameter and the mean velocity of them were carefully measured as well. The site we chose for measuring draining vein diameter was large and was possibly the diameter at the end of inspiration. The mean velocity of the draining veins was acquired automaticly by the instrument when Doppler spectrum was displayed clearly and completely under the condition of the Doppler angle of incidence (between the axis of the Doppler beam and the flow direction) keeping< 60°. Both the diameter and the velocity of the draining veins for calculation were the average value of three times measurements.The HV and IVC lesions were classified into septal obstruction (septum thickness≤1.0cm in HV and ≤1.5cm in IVC), segmental obstruction (obstructed length>1.0 cm in HV and>1.5 cm in IVC), thrombosis and completely occluded HV. The septa both in HV and IVC were shown as transverse or oblique hyperechogenic strip on sonogram or low signal strip on MRI. There was no blood flowing through the occluded septum both on ultrasonogram and MRI, and the reversed flow could be detected on ultrasonogram in the distal part of the lumen from the septum. However, when the septal stenoses existed, the passing-through septum blood could be seen both on sonogram and MRI, with aliasing blood on sonogram or sometime spurting blood on MRI.When segmental stenosis affected the HV and IVC, both the ultrasonograms and MRI revealed that the proximal lumens of the involved vessels were stenosed with a thickening wall. At sites where proximal parts of the involved vessels were obviously stenosed, color and spectral Doppler revealed aliasing and high-velocity. The IVC stenosis caused by compression of enlarged caudate lobe was not included in the segmental stenosis type. The lumen and blood disappeared both on ultrasonogram and MRI when segmental occlusion existed. It was revealed different echogenicity on ultrasonogram and diverse intensity on different MR sequences during the different period of the thrombus in HV, AHV and IVC. Both Sonograms and MRI showed the absence of blood flow in the vessels that were completely thrombosed by fresh thrombus and a blood-filling defect was observed in the vessels that were partly embolized. Complete occlusion of the lumen showed a hyper-echogenicity cord on ultrasonogram and hypo-intensity cord on MRI or no HVs discerned on the normal anatomic position.Ultrasonography and MR were performed 1 to 2 weeks before digital subtraction angiography (DSA) in all patients. According to the results of DSA, the treatment of 52 patients is as follows:Two patients with patent IVCs and 7 with stenosis IVCs caused by compression of enlarged caudate lobes only underwent treatment on HV lesions.14 of the 15 patients with IVC stenoses underwent balloon dilatation and 1 underwent stent-placement of the stenotic segments through the femoral vein. Among the 23 patients with IVC segmental stenoses,2 patients failed to be recanalized due to much thrombosis verified by IVC angiography,18 of the remaining 21 patients who were confirmed through the femoral and internal jugular vein angiography underwent balloon dilatation or stent-placement and 3 of the remaining 21 patients underwent no treatment because of the longer occluded segments and sufficient collaterals. Five patients with septal occlusion confirmed by femoral and internal jugular vein angiography underwent balloon dilatation.The operation procedure expired when the recanalized lumen went patent and the collaterals from which disappeared. The patients with sufficient draining HVs or AHVs (diameter>0.8 cm) and rich collaterals undrewent no treatment of the affected HVs. Percutaneous transhepatic HV stent-placement was performed on 2 patients with HV stenoses,3 patients with accessory HV stenoses and 1 patient with AHV occlusion. The operation procedure also expired when the stent lumen was patent and the collaterals from the affected vessel disappeared.All of the patients were reexamed by ultrasonography at 1-2 weeks,3 and 6 months respectively after operation and the recanalized vessels were evaluated as well. The effective drainage of the HVs based on the followings:disappearing of clinical symptoms, no restenosis of recanalized IVCs and maintaining patent of blood draining vessels. The blood flow volume of the draining vessels was obtained by using the formula Q= (D/2)2×π×V. Where, D indicated the diameter of the draining vessels and V indicated the velocity of the blood, which were obtained from ultrasonography. When more than one draining vessels were revealed, the blood volume was considered as the total of each draining vessel. The effective draining volume of the obstructed HVs should be established by comparing the preoperative blood flow volume with postoperative volume, and by which, it could suggest that the patients who didn’t need further HV recanalization preoperatively.Results:All of the patients in this group were chronic BCS and all patients had HV lesions in different degrees (2/52,100%). Compared with DSA,43 of 52(43/52,83%) patients had mixed BCS, in which obstructed hepatic veins and IVCs co-existed in the same patient. No isolated IVC type (obstruction in only the IVC) was observed in this study. There were 11 normal HVs displayed on ultrasonagram and 12 on MRI, only accounting for 7.1% and 7.7% respectively of the total number of 156 HVs in 52 patients. Among the rest obstructed HVs, 145 were showed on ultrasonagram and 144 on MRI, accounting for 92.9% and 92.3% of all hepatic veins respectively, roughly with an average of 2.8 abnormal hepatic veins per patient.The results showed that ultrasonography was basically in line with MRI to classify the lesions both of HVs and IVCs but each has its own advantages for visualizing some lesions.The lesions of HVs revealed on the two imagings were mainly luminal occlusions, including segmental occlusion, cord-like occlusion and HV disappearance. According to the ultrasonogram and MRI, the HVs lesions were classified into segmental stenosis, segmental occlusion, septal stenosis, septal occlusion, cord-like occlusion and HV disappearance. Ultrasonography was superior to MRI in demonstrating cord-like and segmental occluded HVs, septal lesions of HVs(P<0.05).Dilated AHVs were well detected in this study, including 47(47/52,90.4%) caudate lobe veins on ultrasonogram and 50(50/52,96.2%) on MRI,34(34/52,65.4%) inferior hepatic veins on ultrasonogram and 37(37/52,71.2%) on MRI. Both ultrasonogram and MRI revealed dilation in most AHVs; the distal part of the HVs, which were proximately occluded, drained through communicating branches into AHVs and subsequently into the IVC. The lesions of the AHVs were mainly septal stenosis and thrombus. Two patient with capsule hepatic veins were found on ultrasonograms and 5 on MRI. The courses of the capsule hepatic veins could be demonstrated clearly whereas couldn’t be displayed on ultrasonograms.The IVC lesions were also classified into segmental stenosis, segmental occlusion, septal stenosis, septal occlusion based on the ultrasonogram and MRI. The results of ultrasonography and MRI were basically coincide to diagnose the different types of the lesions except that ultrasonography was superior to MRI to detect the septal lesions. As for the collaterals of the IVCs, only superficial thoracoepigastric veins and part of the lumbar veins could be demonstrated on ultrasonogram.According to the the effective blood drainage criterion mentioned above, that is disappearing of clinical symptoms, no restenosis of recanalized IVCs and maintaining patent of blood draining vessels,30 patients were classified into single-vessel draining group and multi-vessel draining group. By comparing the pre-operational diameter and blood flow volume with post-operational ones of the draining vessels, it showed that the diameter reduced in the single-vessel draining group whereas the blood flow volume increased both in single-vessel and multi-vessel draining group. The results suggested that if the IVCs were unobstructed or could be recanalized, the preoperative draining blood flow volume ranging from (8.46±1.62) ml/s (single draining vein) to (8.60±2.47) ml/s (multi-draining veins) could be effective drainage.Conclusions:Ultrasonography combining with MRI provides much more information in diagnosing BCS, which can clearly display the HVs, AHVs, IVCs and their lesions as well as classify the lesions. Moreover, the established effective blood flow volume of the draining vessels can be used as a guideline to deal with the HV lesions. Complex treatment of obstructed hepatic veins can be avoided in the patients with effective blood drainage. |
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