The MRI features of acute and chronic Budd-Chiari syndrome (BCS) were studied to investigate the diagnostic value of MRI for acute and chronic BCS. Methods Eleven consecutive patients with acute BCS admitted from March 2011 to February 2012 were used as the acute group, and 42 consecutive patients with chronic BCS admitted during the same period were used as the chronic group. The MRI findings of the two groups were retrospectively analyzed. Abdominal water volume was compared between the two groups using Wilcoxon W rank sum test;
The proportion of intra- and extra-hepatic traffic branch formation was compared between the two groups by Fisher’s exact probability method. In the acute group, T2WI high signal hepatic vein thrombosis was found in all patients, including three patients with inferior vena cava thrombosis; compared with the central zone of the liver, the peripheral zone of the liver showed slightly low signal in T1WI and slightly high signal in T2WI. In the chronic group, there were 3 cases of simple inferior vena cava obstruction, 9 cases of simple hepatic vein obstruction, and 30 cases of combined hepatic and inferior vena cava involvement, and only 3 patients had venous thrombus with high signal in the inferior vena cava on T2WI.
In the chronic group, all patients showed signs of bruising cirrhosis, and there was no significant difference in the signal between the peripheral zone and the central zone of the liver in the chronic BCS patients on MR scan and enhanced scan.
All patients in the acute group had ascites formation (2 cases of moderate ascites and 9 cases of massive ascites), while 22 patients (52.4%) in the chronic group had ascites formation (15 cases of small ascites, 2 cases of moderate ascites, and 5 cases of massive ascites), and the amount of ascites in the acute group was greater than that in the chronic group, Z=4.15, P<0.01; 2 cases of intrahepatic traffic branch formation and 1 case of extrahepatic traffic branch formation in the acute group, 37 cases of intrahepatic traffic branch formation and 34 cases of extrahepatic traffic branch formation in the chronic group. The proportion of patients with intrahepatic and extrahepatic traffic branch formation in the acute group was lower than that in the chronic group (P<0.01), and the differences between the above indexes were statistically significant.
Conclusion MRI examination can accurately display various direct and indirect signs of BCS, and can make an accurate diagnosis of acute and chronic BCS. Cheng Delei, Department of Interventional Radiology, Anhui Provincial Hospital
BCS can be divided into acute BCS and chronic BCS according to the duration of the disease, which is generally considered to be chronic BCS with a duration of >6 months.
MRI can provide a comprehensive evaluation of intra-abdominal organs as well as blood supply vessels and can be used as a separate, noninvasive method for diagnosing BCS. Some studies have reported that MRI can diagnose BCS, however, because of its low prevalence, few studies have been reported on specific MRI imaging features of acute and chronic BCS. Therefore, we performed a comprehensive retrospective analysis of MRI findings in patients with new (initially diagnosed) BCS at our hospital from March 2011 to February 2012, and the results are reported below.
Materials and methods
I. Patient data and diagnostic criteria
1. Patient data.
(1) Acute group: 11 consecutive cases of new-onset acute BCS patients, 6 males and 5 females, aged (23±5) years, with a duration of illness of (1.6±0.8) months, and a glutamate aminotransferase (ALT) of (404±140) U/L, were selected according to the following corresponding diagnostic criteria from March 2011 to February 2012.
(2) Chronic group: 42 consecutive patients with new-onset chronic BCS, 25 males and 17 females, aged (46±11) years, with a disease duration of (135.0±104.0) months and ALT of (41±43) U/L, were selected according to the following corresponding diagnostic criteria. was higher than that of the chronic group (Z=2.9, P<0.01). Another 18 patients were excluded from this study because their medical history was unknown and the exact staging could not be determined.
The main clinical symptoms and signs of patients in both groups were abdominal pain, bloating, dyspepsia, varicose veins on the body surface, lower limb edema, hyperpigmentation and ulcers. All patients were admitted to the hospital with mr examination first, and dsa examination was performed within 1 week to confirm the diagnosis and interventional treatment. < p="">
2. diagnostic criteria: refer to Singh V staging [2]: BCS of ≤6 months duration is defined as acute BCS; duration >6 months is defined as chronic BCS. amount of ascites: MR examination shows limited ascites in the subdiaphragm, liver, kidney, spleen, kidney or cysto-rectal space as a small amount of ascites; diffuse ascites in the middle and lower abdomen and lateral abdomen, between the intestinal canal and around the parenchymal organs as a moderate amount of ascites; the whole abdominal cavity shows ascites The whole abdominal cavity is filled with ascites, and the intestinal canal is floating or fixed in it as a large amount of ascites. Definition of vascular occlusion: MR examination showed that the length of occluded segment vessels >1 cm was segmental occlusion and ≤1 cm was membranous occlusion.
Second, examination and image evaluation methods
1.Examination method:MR examination was performed with the American GE Signa EXCITE 3.0 T MR whole-body imaging system with 8-channel abdominal Torsopa coil. Conventional TlWI, T2WI and FIESTA sequences, enhanced scanning lines in axial, coronal and sagittal planes. Scanning parameters: breath-hold LAVA volume scan sequence, 3D mode, matrix 288×256, inversion angle 12°, bandwidth 83.33 Hz, FOV 40 cm×40 cm, layer thickness 4.4 mm, forearm intravenous indwelling needle connected to a high-pressure syringe (Ulrich, Germany), contrast agent using Gd-DTPA (Bayer Schering, Germany) 0.1
After contrast injection, 20 ml of saline was used to rinse the scans.
cava (IVC) lesions.
2. Analysis of imaging results: Two senior imaging specialists evaluated BCS-related lesion features on MR images separately, and in case of inconsistent results, consensus results were obtained by consultation. The lesion features to be evaluated include.
(1) HV and IVC obstructive lesion features.
(2) morphological changes in the liver.
(3) T1WI and T2WI signal distribution characteristics, and
(4) characteristics of dynamic enhancement, and
(5) the presence or absence of venous collateral circulation.
(6) signs of portal hypertension such as ascites and spleen enlargement.
Statistical treatment
Qualitative data were expressed as percentages, and quantitative data were expressed as mean ± standard deviation. For comparison between two groups of quantitative data, the Kolmogorov-Smimov method was used to test the normality of quantitative data; the t-test for age and maximum transverse diameter of the spleen were used for independent samples, and the Wilcoxon W rank sum test was used for ALT not conforming to normal distribution; the Fisher exact probability method was used for comparison between two groups of qualitative data;
Likelihood ratio χ2 test was used for comparison between two groups for vascular lesion location; Wilcoxon W rank sum test was used for comparison between two groups for grade data for abdominal water; P<0.05 was considered statistically significant difference. All statistical analyses were performed using SPSS 16.0 statistical software.
Results
I. MRI characteristics of the acute group
1, MRI characteristics of HV and IVC: MRI showed that all patients in the acute group had thrombosis in HV, including 3 cases of combined IVC thrombosis; all patients had compressive stenosis in the IVC lumen. 2 cases showed high signal + mixed signal, 3 cases high signal + low signal, 1 case mixed signal, 1 case high signal, 4 cases simple low signal on T1WI images, and 3 cases showed high signal + mixed signal on T2WI images. High signal + mixed signal, 3 cases of high signal + low signal, 5 cases of simple high signal, filling defects of low signal in the veins were seen in the venous phase of dynamic enhancement scan.
2. MRI characteristics of liver: 11 patients showed abnormal signal areas in the peripheral zone of the liver on MRI images, with slightly low signal in T1WI and slightly high signal in T2WI, and the degree of enhancement was relatively reduced in both the arterial and venous phases on enhancement scans. The thrombus formation with high signal in T2WI can be seen in the drainage veins of the liver in this area; the central zone shows relatively normal liver tissue signal in T1WI, T2WI and the arterial and venous phases of the enhancement scan.
3. Other BCS signs: all patients in this group had ascites formation; five of them had enlarged spleens; two cases had formed intrahepatic branches between HV and one case had formed extrahepatic traffic branches between HV and body veins.
II. MRI characteristics of chronic group
MRI characteristics of HV and IVC: 3 cases (7.1%) of simple IVC obstruction, 9 cases (21.4%) of simple HV obstruction, 30 cases (71.4%) of simultaneous HV and IVC involvement; 6 cases (14.3%) of IVC thrombosis in this group, including 1 case of high signal, 3 cases of mixed signal and 2 cases of low signal in T1WI image, and 3 cases of high signal and 1 case of mixed signal in T2WI image. 3 cases, 1 case of mixed signal and 2 cases of low signal on T2WI.
All patients in this group were found to have obstructive lesions with double low signal on T1WI and T2WI on IVC and/or HV, and low signal filling defects in the veins were seen in the venous phase on enhanced scans. In our group, there were 33 (78.6%) IVC obstructions, including 17 (17/33, 51.5%) membranous occlusions, 11 (11/33, 33.3%) segmental occlusions, and 5 (5/33, 15.2%) stenoses; among the 39 (92.9%) HV obstructions, 12 (12/39, 30.8%) HV opening stenoses and 21 (21/39, 53.8%) membranous occlusions were found. (21/39, 53.8%), and segmental occlusion in 14 cases (14/39, 35.9%) (the same patient could have 2 lesions).
2. Liver MRI features: 19 of 42 cases (45.2%) had hepatic signal heterogeneity with scattered small pieces of long T1 and long T2 signals, while 23 cases (54.8%) had relatively homogeneous liver signals; there was no significant difference between the signals in the peripheral zone of the liver and the central zone during T1WI, T2WI and dynamic enhancement scans.
Seven patients (16.7%) had multiple intrahepatic nodules with slightly high signal on T1WI and isosignal or slightly low signal on T2WI, which were significantly enhanced on enhancement scan; two of them (2/7, 28.6%) were diagnosed as primary hepatocellular hepatocellular carcinoma in combination with clinical and laboratory examinations (one case with methemoglobin higher than 1000 μg/L and one case with methemoglobin 45 μg/L, confirmed by puncture biopsy were hepatocellular hepatocellular carcinoma), but their MRI features were not significantly different from other benign nodules.
MR examination in 42 cases showed signs of bruising cirrhosis such as disproportionate liver lobes and wavy changes in the liver envelope. 7 cases (16.7%) had diffuse liver enlargement, 5 cases (11.9%) had relatively normal liver volume, and 30 cases had relatively reduced liver volume (Table 1).
3, other BCS signs: specific and comparison with the chronic group is shown in Table 1, the incidence of ascites was lower than that of the acute group; the mean value of the maximum diameter of the spleen was greater than that of the acute group; the proportion of traffic branch formation inside and outside the liver was higher than that of the acute group.
Table 1 Comparison of MRI features in patients with acute and chronic Buga syndrome (cases)
Group
Number of cases
T2WI high signal
Ascites
Enlarged liver volume
caudate lobe enlargement
Intrahepatic nodules
Massive
Moderate Small amount
Acute group
11
11
9
2
0
11
2
0
Chronic group
42
3
5
2
15
7
32
7
Z-value
P-value
P-value
0.000
4.15
0.000
-0.000
0.000
0.000 – 0.000
0.001
-0.322
0.322
Group
Number of cases
Spleen diameter (cm)
Lesion location
Intrahepatic communicating branch formation
Extrahepatic traffic branch formation
Parahepatic vein
A B
C
Acute group
11
11.2±2.0
8
0
3
2
1
2
Chronic group
42
15.4±2.4
9
3
30
37
34
30
χ2 value
P-value
4.9*
0.000
10.5
0.005
-0.005
0.000
-0.000
0.000
-0.004
0.004
Note: A: hepatic vein involvement alone, B: inferior vena cava involvement alone, C: combined involvement, *: is t-value, -: no value
Discussion
The lesions and clinical features of acute and chronic BCS are very different, and their treatment and prognosis are different. Acute BCS is mostly caused by intrahepatic vein thrombosis, with rapid onset, severe symptoms, poor prognosis and high mortality rate, and the treatment effect of angioplasty is poor, and most patients need internal jugular vein portal shunt or liver transplantation. Chronic BCS is mostly caused by intravenous occlusion, with relatively mild symptoms and better results of angioplasty treatment.
Therefore, a correct diagnosis of acute and chronic BCS can help to select a reasonable treatment plan, effectively relieve BCS-related symptoms and improve the survival rate of patients. However, the insidious onset of some BCS patients makes it clinically difficult to accurately stage them according to the disease duration. In this study, the MRI characteristics of acute and chronic BCS patients were studied in a controlled manner, and it was found that MRI examination could not only show various lesions of BCS, but also accurately stage BCS patients according to their lesion characteristics.
The results of this study showed that MRI dynamic enhancement scans and three-dimensional reorganization techniques can not only display obstructive lesions in HV and IVC, but also accurately determine the morphology of obstructive lesions (stenosis, membranous or segmental occlusion). However, because the enhanced scans of various HV and HVC obstructive lesions show low signal without contrast filling in the veins, it is not possible to determine the degree of old and new obstructive lesions, which is not very helpful for BCS staging.
Mo Youfa et al. found that acute portal vein thrombosis showed high signal on T2WI images and chronic portal vein thrombosis showed low signal on T2WI images. Similar results were found in the present study, where obstructive lesions (thrombi) with high T2WI signal were found in HV and/or IVC in all patients with acute BCS; whereas no obstructive intravenous lesions with high T2WI signal were found in the chronic group of 42 patients, except for 3 (7.1%) with combined IVC thrombosis.
Therefore, T2WI high-signal obstructive lesions (fresh thrombus) are a reliable indicator for the diagnosis of acute BCS. From the above analysis, it is easy to see that MRI examination on admission of BCS patients can not only show the morphology of HV and/or IVC obstructive ends of patients, but also determine the duration of intravenous thrombosis, which can guide the clinical selection of a reasonable treatment plan.
In this study, all patients in the acute group had abnormal signal areas in the peripheral zone of the liver, and thrombus formation was seen in the draining HV in this area, while the central zone of the liver showed normal liver tissue signal characteristics; however, there was no significant signal difference between the peripheral zone and the central zone of the liver in the chronic group.
In acute BCS patients, the thrombosis in the HV is mostly caused by the short duration of the disease, and the compensating collateral vessels have not yet formed around the obstructed HV, so the obstructed HV drainage area has severe liver stasis, which leads to cellular edema and necrosis; whereas the central zone of the liver is the area where the caudate lobe is located, and there is an independent drainage vein (short hepatic vein), so the lesion is relatively mild, so it shows relatively normal liver tissue signal on each sequence of MRI images. The signal of liver tissue is relatively normal on all sequences of MRI. In chronic BCS, there is no significant difference in signal between the peripheral and central zones of the liver because of the long duration of the disease and the formation of a large number of intrahepatic and extrahepatic collateral circulation.
In the present study, all patients in the chronic group showed signs of bruising cirrhosis such as disproportionate lobe of the liver and wavy changes in the liver envelope, and some patients could have atypical hyperplastic nodules in the liver;
The patients in the acute group had a homogeneous enlarged liver morphology and a higher proportion of patients with ascites, while chronic compensatory indexes such as intra- and extra-hepatic traffic branches, parahepatic veins and spleen diameter were significantly lower than those in the chronic group. Through the above analysis, it is easy to find that various indirect signs of BCS, such as abnormal signals in the peripheral zone of the liver, liver morphology, and intra- and extrahepatic collateral circulation, are also important indications for differentiating acute and chronic BCS.
In summary, both acute and chronic BCS have their characteristic MRI manifestations, and MRI examination can not only show direct signs of BCS, i.e., the site and extent of venous obstruction, but also various indirect signs of BCS (e.g., collateral vessels inside and outside the liver, enlargement of the caudate lobe of the liver, hepatic stasis and edema, regenerative nodules, etc.). The comprehensive analysis of various direct and indirect signs can accurately diagnose acute and chronic BCS, and then guide the clinical selection of a reasonable treatment plan.