|Year : 2015 | Volume
| Issue : 2 | Page : 57-63
Ultrasound Determination of Portal Vein Diameter in Adult Patients with Chronic Liver Disease in North-Eastern Nigeria
Aminu Umar Usman1, Philip Ibinaiye2, Ahmed Ahidjo3, Abdurrahman Tahir3, Sulaiman Tanimu Sa'ad1, Zainab Mustapha3, Nasiru Tahir1, Sani Garko1
1 Department of Radiology, Federal Teaching Hospital, Gombe, Nigeria
2 Department of Radiology, Ahmadu Bello University Teaching Hospital, Zaria, Kaduna State, Nigeria
3 Department of Radiology, University of Maiduguri Teaching Hospital, Maiduguri, Borno State, Nigeria
|Date of Submission||30-Sep-2014|
|Date of Acceptance||25-Feb-2015|
|Date of Web Publication||20-May-2015|
Dr. Aminu Umar Usman
Department of Radiology, Federal Teaching Hospital, Gombe
Background: Despite the safety, affordability and widespread use of ultrasound; there is a paucity of literature on ultrasonographic assessment of the portal vein (PV) diameter in adult patients in our local environment. Aims and Objective: The aim of this study was to determine the mean and range of PV diameter in chronic liver disease (CLD) patients in our local environment. Materials and Methods: This cross-sectional prospective study was carried out at the University of Maiduguri Teaching Hospital between January and June, 2013. Two hundred and fifty adult male and female CLD patients and equal number of age and sex matched controls aged 18 years and above had abdominal ultrasonography for measurement of their main, right and left PV diameter in both inspiration and expiration. Transverse and longitudinal measurements were obtained, and the averages of the two measurements were used to determine their final diameter. Results: There were 187 (74.8%) male and 63 (25.2%) female CLD patients aged between 19 and 77 years (mean ± standard deviation [SD], 43.78 ± 12.97 years). The mean diameter of the main PV (±SD) in CLD was 18.68 ± 2.59 mm which is higher than that of the control (10.87 ± 0.81 mm). The mean diameter of the right and left PVs in CLD were 9.04 ± 1.26 mm and 8.58 ± 1.23 mm respectively, which were higher than the respective values of 4.35 ± 0.52 mm and 4.12 ± 0.52 mm in the control. The PV diameter correlated with age and respiratory phases in both CLD and the control group (P < 0.05). There was statistically significant difference in PV diameter between males and females (P < 0.05) with values higher in females. Conclusion: The mean value and range of PV diameter in CLD patients in this environment were statistically and significantly higher than controls. The diameter correlated with age and showed significant difference between the two sexes and respiratory phases.
Keywords: Chronic liver disease, portal vein diameter, ultrasound
|How to cite this article:|
Usman AU, Ibinaiye P, Ahidjo A, Tahir A, Sa'ad ST, Mustapha Z, Tahir N, Garko S. Ultrasound Determination of Portal Vein Diameter in Adult Patients with Chronic Liver Disease in North-Eastern Nigeria. Sub-Saharan Afr J Med 2015;2:57-63
|How to cite this URL:|
Usman AU, Ibinaiye P, Ahidjo A, Tahir A, Sa'ad ST, Mustapha Z, Tahir N, Garko S. Ultrasound Determination of Portal Vein Diameter in Adult Patients with Chronic Liver Disease in North-Eastern Nigeria. Sub-Saharan Afr J Med [serial online] 2015 [cited 2021 Mar 1];2:57-63. Available from: https://www.ssajm.org/text.asp?2015/2/2/57/157419
| Introduction|| |
Chronic liver disease (CLD) is a disease of the liver resulting from an inflammatory, infiltrative, immunologic, mechanical or metabolic injury to the liver which has persisted for 6 or more months without complete resolution. 
The etiology of CLD includes viral agents, parasites, granulomatous liver diseases, drugs, metabolic diseases, hepatic cysts, alcohol, autoimmune diseases, and amyloidosis. ,
Signs of CLD can be divided into those associated with the etiology and those associated with decompensation. Those associated with etiology include Dupuytren's contracture, parotidomegaly, peripheral neuropathy, cerebellar signs, increase skin pigmentation and tattoos; while those associated with decompensation include drowsiness, hyperventilation, asterixis, jaundice, ascites, leukonychia, peripheral edema, and bruising.
There is marked variation in the epidemiology of CLD. The prevalence of CLD in Italy was 17.5%;  while in United State, the incidence was 63.9 cases/100,000 population.  The prevalence rates of hepatitis C and B (important causes of CLD) in Nigeria is 4.8% and 9.5% respectively. 
The portal vein (PV) is a unique vein that drains blood from the capillaries of the intestinal walls and spleen to the capillaries of the hepatic sinusoids. The major abnormality of the portal venous system in CLD is portal hypertension; this result from an increased resistance to portal venous flow and/or increase in blood flow. The result of this mechanism is the enlargement of both intrahepatic and extrahepatic PVs and subsequent development of portosystemic collateral vessels. 
Conventional angiography, computed tomography angiography and magnetic resonance angiography can be used to evaluate PV changes in CLD patients. However, ultrasound scan is preferred because it is a safe, noninvasive, cheap and readily available diagnostic tool for evaluating these patients. It is also important in monitoring of progression of the disease. 
This study was aimed at evaluating the diameter of both intrahepatic and extrahepatic PV s which is useful in the diagnosis of portal hypertension in CLD patients.
| Materials and Methods|| |
This cross-sectional prospective study was carried out from January to June 2013. The case group includes; CLD patients who meet the inclusion criteria and the control group consist of apparently normal individuals. Data were collected on the structured data collection form that consists of items for the patient's age, gender, and the ultrasound findings.
The study was carried out at the University of Maiduguri Teaching Hospital (UMTH) Maiduguri, Nigeria.
The study population consists of two groups; Group A were CLD patients attending gastroenterology clinic or admitted to the medical ward that meet the inclusion criteria while Group B (control) consists of apparently normal age and sex matched patients attending the general outpatient department and meet the inclusion criteria.
Inclusion criteria for Group A
These criteria included subjects of 18 years and above and ultrasonographic evidence of CLD, which included increased hepatic parenchymal echogenicity, shrunken liver with irregular surface and/or evidence of hepatic masses.
Exclusion criteria for Group A
These included subjects below 18 years of age, pregnant women because of the physiological liver changes in pregnancy, subjects on hapatotoxic drugs such as anti-tuberculous and antiretroviral drugs.
Inclusion criteria for Group B (control)
These included age-matched healthy males and females 18 years and above and normal B-mode ultrasonography findings in the liver
Exclusion criteria for Group B (control)
Included subjects below 18 years of age, subjects at risk of CLD such as alcohol ingestion or hepatitis B surface antigen positivity, pregnant women, subjects on hapatotoxic drugs such as anti-tuberculous and antiretroviral drugs, ultrasonographic evidence of liver diseases.
The PV ultrasound examination was explained to each subject and a brief history obtained. Biodata, which include age and sex was recorded for each patient.
Prior to the examination patients were asked to fast for at least 6-8 h. This reduces excess bowel gas that may obscure the main PV and distends the biliary ducts. The examination was performed using a high-resolution real-time Doppler ultrasound scanner (Aloka, SSD-3500) equipped with 3.5 MHz curvilinear transducer. This transducer provides excellent resolution for deep abdominal visceral organs such as the liver.
The ultrasound examination was conducted in the supine position. Ultrasound gel was applied, and transducer placed in the epigastrium in both transverse and longitudinal planes to evaluate the main PV, and right hypochondria region to evaluate the right and left PVs. The intrahepatic PVs in some patients were also examined in sub-coastal or inter-coastal approach with the patient either in supine, right anterior oblique or left posterior oblique as needed. In patients with excess gas in the duodenum and antrum that obscured the distal extrahepatic PV, they were placed in an erect right anterior oblique position to displace the air.
The PVs were identified using color Doppler, which differentiates them from the adjacent hepatic arteries and bile ducts. Antero-posterior (AP) and transverse diameter of the main PV were measured at its midpoint (A to B), while the values for right PV (C to D) and left PV (E to F) were measured at the level of their bifurcation [Figure 1] and [Figure 2]. The AP diameter from proximal to distal wall was obtained using the longitudinal view while the transverse diameter from the medial to lateral wall was obtained from the transverse view [Figure 3].
|Figure 1: Longitudinal view of the abdomen in a chronic liver disease patient showing shrunkened and echogenic liver (L), dilated portal vein and ascites (A)|
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|Figure 2: Longitudinal view of the abdomen showing the levels of measurement of the portal vein (PV) (white arrows), right PV (black star), and left PV (white star). IVC represents the inferior vena cava.|
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|Figure 3: Transverse view of the portal vein showing the levels of measurement (white arrows). IVC represents the inferior vena cava.|
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Data management and statistical analysis were done using Statistical Package for Social Sciences (SPSS) for Windows version 16.0 packages (SPSS Inc., IL, USA). Descriptive statistics which include mean, mode, median and standard deviation (SD) were used to describe the diameter of the PVs.
The correlation between the diameters with age was evaluated using Pearson's correlation test. Statistical significance was assessed using Student's t-test to compare the mean PV diameter between the two sexes, compare the difference between the mean right and left PV diameters and respiratory phases with a P value set at 0.05.
The detailed description of the descriptive statistics, correlations and differences were presented in form of tables and graphs.
Informed written consent was obtained from the patients before enlistment into the study. An approval to carry out the study was obtained from the Ethical Committee of the UMTH.
| Results|| |
The study was performed on 250 consenting adults with CLD patients and same number of age and sex matched controls. One hundred and eighty-seven (74.8%) were males and 63 (25.2%) were females in both the CLD and control groups respectively.
The age range was 19-77 years with a mean (±SD) 43.78 ± 12.97 for both subjects and control. Seventy-eight were in the age group of 41-50 years (31.2%), while the least number of patients were in the younger age group of <20 years (2.8%) in both the subjects and control groups [Table 1].
|Table 1: Sex distribution pattern of the study population based on age group|
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The modal age in males is 41-50 years while in females is 31-40 years.
[Figure 4] is a bar chart showing the age distribution pattern of the population in the study.
|Figure 4: Bar chart showing the various age group and the frequency of thier distribution in the study population|
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[Table 2]a shows the difference in the mean PV diameter in the various age groups in male CLD patients and the difference in the values is statistically significant (P = 0.000).
The main PV diameter in male CLD patients was highest in <21 years old age group with a value of 22.27 ±0.98 mm. The values tend to be decreasing with age confirming a negative correlation (r = −0.237). The overall main PV diameter was found to be 18.55 ± 2.59 mm.
However, the main PV diameter in control was highest in 71-80 years age group with a value of 12.51 ± 0.47 mm. The values tend to be increasing with age confirming a positive correlation (r = 0.756). The overall main PV diameter was found to be 10.94 ± 0.84 mm.
The overall mean diameter of the main PV in male CLD patients (18.55 ± 2.59 mm) was higher than that of the control (10.94 ± 0.84 mm) and the difference between the values is statistically significant (P = 0.000).
The total mean diameter of the right PV in male CLD patients (8.99 ± 1.24 mm) was higher than that of the left (8.57 ± 1.24 mm) and their difference is statistically significant (P = 0.000).
The corresponding value of the right PV in the male control (4.38 ± 0.54 mm) was also higher than that of the left (4.15 ± 0.56 mm) and their difference is statistically significant (P = 0.000).
[Table 2]b also shows the difference in the mean PV diameter in the various age groups in female CLD patients and the difference in the values is statistically significant (P = 0.000).
The main PV diameter in female CLD patients was highest in <21 years old age group with a value of 22.47 ± 0.02 mm. The values tend to decrease with age confirming a negative correlation (r = −0.212). The overall main PV diameter was found to be 18.84 ± 2.46 mm.
However, the main PV diameter in control was highest in 71-80 years age group with a value of 12.41 ± 0.02 mm. The values tend to increase with age confirming a positive correlation (r = 0.606). The overall main PV diameter was 10.65 ± 0.66 mm.
The overall main PV diameter in the female CLD patients (18.84 ± 2.46 mm) was significantly higher than that of the control (10.65 ± 0.66 mm) and the difference between the values is statistically significant (P = 0.000).
The total mean diameter of the right PV in female CLD patients (9.19 ± 1.27 mm) was higher than that of the left (8.26 ± 1.21 mm) and the difference is statistically significant (P = 0.000).
The corresponding value of the right PV in the female control (4.24 ± 0.41 mm) was also higher than that of the left (4.02 ± 0.39 mm) and the difference is statistically significant (P = 0.000).
Mean diameter of the main PV in male CLD (18.55 ± 2.59 mm) is lower than that of females (18.84 ± 2.46 mm), and the difference is statistically significant (P = 0.000). The corresponding value of the mean diameter of the main PV in male controls (10.94 ± 0.84 mm) is, however, higher than that of females (10.65 ± 0.66 mm) and the difference is statistically significant (P = 0.000).
[Table 3] shows the range and mean diameter of the main PV, right and left PV s in CLD patients and the control group.
|Table 3: Descriptive statistic of the total diameter of the Main, right and left portal veins|
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The mean diameter of the main PV in CLD (18.68 ± 2.59 mm) was higher than that of the control (10.87 ± 0.8 mm) and the difference between the values is statistically significant (P = 0.000).
The mean diameter of the right PV in CLD (9.04 ± 1.26 mm) was also higher than that of the control (4.53 ± 0.52 mm) and the difference between the values is also statistically significant (P = 0.000).
Similarly, the mean the left PV diameter in CLD (8.58 mm ±1.23 mm) was higher than that of the control group (4.12 mm ± 0.52 mm) and the difference between the values is statistically significant (P = 0.000).
[Table 4]a shows that the mean diameter of the main, right and left PV diameter of male CLD patients on inspiration were 18.72 ± 2.6 mm, 9.09 ± 1.28 mm and 8.65 ± 1.27 mm respectively, which were higher than the corresponding values on expiration (18.38 ± 2.55 mm, 8.89 ±1.26 mm and 8.48 ±1.25 mm). The difference between values on inspiration and expiration is statistically significant (P = 0.000).
The values in female CLD patients on inspiration were 19.31 ± 2.63 mm, 9.31 ± 1.41 mm and 8.77 ± 1.29 mm; which were also higher than the corresponding values on expiration (18.84 ± 2.46 mm, 9.06 ± 1.16 mm and 8.47 ± 1.53 mm). The difference between values on inspiration and expiration is also statistically significant (P = 0.000).
[Table 4]b shows that the mean diameter of the main, right and left PV diameter of male controls on inspiration were 10.95 ± 0.84 mm, 4.15 ± 0.56 mm and 4.38 ± 0.54 mm respectively which were higher than the corresponding values on expiration (10.23 ± 0.79 mm, 4.02 ± 0.47 mm and 4.15 ± 0.56 mm). The difference between values on inspiration and expiration is statistically significant (P = 0.000).
The values in female controls on inspiration were 10.64 ± 0.65 mm, 4.01 ± 0.39 mm and 4.25 ± 0.42 mm, which were also higher than the corresponding values on expiration (10.23 ± 0.52 mm, 3.89 ± 0.23 mm and 4.02 ± 0.40 mm). The difference between values on inspiration and expiration is also statistically significant (P = 0.000).
| Discussion|| |
A study done by Ndububa et al. in South-Western Nigeria on 145 patients on the contribution of alcohol to development of CLD had more males (102) than females (43). A study of 108 CLD patients by Kamran et al. on correlation between sonographic PV diameter and flow velocity in cirrhotic patients also had more males (66) than females (42). Maaji et al.  also had male predominance in his study on sonographic findings of CLD patients in Sokoto. These findings concorded with this study confirming male predominance in CLD in our environment. The male dominance in this study was possibly due to high alcohol intake and increased risk of hepatitis B infection which increases the risk of the disease.
A study done by Lopamudra et al. on 82 CLD patients found a higher value of mean PV diameter of 13.99 ± 1.12 mm. Nizar et al. also reported an increased PV diameter of up to 17 mm. In another study  on 107 CLD patients also found an increase in diameter of the extrahepatic PV which was >13 mm. Similar studies done also showed increase in diameter of the main PV.  In this study, the mean diameter of the main PV in CLD patients was higher (18.68 ± 2.59 mm) than that of the control (10.87 ± 0.81 mm). The variation in the values of the main PV diameter in the various studies may be due to the difference in sample size, ethnic and geographical differences between the populations studied.
Hawaz et al. reported an increase in diameter of PV with increase in age in normal individuals which is consistent with the finding of Anakwue et al.  Similar findings were also found by many researchers. [16, 17, 18] However, Jeffry et al. and other researchers  found no significant correlation between PV diameter with age. This study found a negative correlation between the diameter of the main, right and left PVs with age in male and female CLD patients and a positive correlation between the values with age in the control group.
Yazdanpanah et al. in his study on 191 CLD patients and 247 controls reported no difference in PV diameter values between male and females in both groups. However, Hawaz et al.  and Anakwue et al.  found correlation between PV diameter with sex in CLD patients, but they found no correlation between PV diameter and sex in normal subjects. This study found no significant difference PV diameter in male and females in CLD patients (P > 0.005). However, there was a statistical difference in the control group (P < 0.05) with values slightly higher in females than males.
A study by Trigaux et al.  on 50 CLD patients and 50 controls, however, found the left PV diameter to be higher than the right in CLD patients while the right being higher than the left in the control group. This study found a significant difference between right and left PV diameter in male CLD patients and control group (P < 0.005). No difference was, however, found in female CLD patients (P > 0.005).
A study by Bolondi et al showed no difference between PV diameter and phases of respiration. However, Rokni and Khalilian  on a study on 36 cirrhotic patients found an increase in the diameter of the PV on inspiration which agrees with another study by Bolondi et al. In this study, there was a statistically significant difference between the values of PV diameter with phases of respiration (P < 0.000) in both CLD and control groups with values higher in inspiration.
Limitations of the study
- Adequate visualization of the extrahepatic PV on ultrasound was difficult in some patients due to excess bowel gas shadows.
- Obesity is another factor that interfered with adequate evaluation of the PVs using ultrasound.
- Difficulties in Doppler examination could occur due to involuntary breathing movement. This was overcome by performing the scan in arrested respiration until a better view is achieved.
| Conclusion|| |
The mean value and range of PV diameter in CLD patients in this environment were statistically and significantly higher than controls. The diameter correlated with age and showed significant difference between the two sexes and respiratory phases.
| Recommendations|| |
- Only 2.8% and 3.6% of the study population were <20 years and older than 70 years respectively. Further studies should be done focusing on these extreme of ages in the population.
- It is essential to have a multi-centered approach to the study to validate the values obtained and to help in establishing standard reference values for PV diameter in Nigeria.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2], [Table 3], [Table 4]
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