Abstract
Background
Sonography is a valuable tool in the assessment of porto-systemic pathologies. This study aimed at determining the mean portal vein diameter based on age, gender and anthropometric variables.
Methods
A cross sectional study conducted among 201 apparently healthy adults in Bauchi Metropolis. Participants were recruited from the school of nursing AbubakarTafawa Balewa Teaching Hospital (ATBUTH), Bauchi. Ultrasound machine ALOKA SSD-1000, (IP-1233EV, SN-57324, Japan) with curvilinear transducer with frequency of 3–5MHz was used for a period of four months, (December 2015 to April 2016). Participants' heights were measured while standing against a meter rule with the head in Frankfurts' position and weight measured using a weighing scale. Data analysis was done using SPSS version 22.0. Descriptive statistics (mean, standard deviation), and Pearson's Correlation were used.
Results
The mean portal vein diameter was 9.60 ± 1.41mm for both sexes. The mean value for males was 9.71 ± 1.42mm, and 9.35±1.46mm among females. There was a positive correlation correlation between the PV diameter and Body Mass Index (P ≤ 0.01).
Conclusion
This study found the mean values of PV diameter in apparently healthy adults in our environment to be 9.60 ± 1.41mm and that PV diameter positively correlates with anthropometric variables.
Keywords: Portal vein diameter, sonography, Nigerian population, healthy adults
Introduction
The portal vein (PV) and hepatic artery forms the liver's dual blood supply. Majority (about 75%) of hepatic blood flow is derived from portal vein while the remainder comes from the hepatic artery. The portal vein (PV) is formed by the confluence of superior mesenteric vein and splenic vein, behind the neck of the pancreas at the level of second lumbar vertebra1. Sonographic measurement of the portal vein diameter is a corner stone and also has a reasonable accuracy in diagnosing patients suspected of having portal hypertension2. The intricate relationship between the liver and the portal vein maintains homeostasis in the human body1.
The major abnormality of the portal venous system is portal hypertension which may occur due to increased re sistance to portal blood flow due to alterations in the liver architecture that leads to enlargement of extrahepatic and intrahepatic portal vessels and the development of portosystemic collaterals3.The formation of portosystemiccollaterals may leads to splenomegaly, ascites, encephalopathy among others4. Diagnostic imaging methods like portal venography, splenoportography, and arteriography have been used to evaluate patients suspected of having portal thrombosis which are invasive, expensive, time consuming and involve risk and discomfort to the patient, while computed tomography and magnetic resonance imaging have advantages of better cross sectional images but are both expensive and the former exposes patient to high doses of ionizing radiation5,7.
Sonography, in addition to its use of non-ionizing radiation, its accessibility, non-invasive nature, portability, low cost and ability of rapid accomplishment, makes it a good diagnostic tool which plays a great role in the diagnosis and follow up of patients with portal hypertension2. These examinations are often challenging and sonogra phers must be confident in their use and manipulation of equipment, and have thorough knowledge and understanding of the anatomy and pathophysiology of the disease process.
This study therefore intends to determine the mean values of portal vein diameter in apparently healthy Northern Nigerian adults.
Materials and methods
This was a cross-sectional prospective study carried out among apparently healthy adult subjects in Abubakar Tafawa Balewa University Teaching Hospital (ATBUTH) Bauchi, for a period of four months from December, 2015 to April, 2016. Ethical clearance was obtained from the ethical committee and the head of Radiology department in Abubakar Tafawa Balewa University Teaching Hospital, Bauchi, and informed consent was obtained from all the participants, prior to the study. Participants were recruited (Voluntarily) from the school of Nursing ATBUTH, Bauchi and other staff of the hospital who gave their consent.
Inclusion and exclusion criteria: Apparently healthy individuals with normal ultrasound findings of the liver formed the inclusion criteria while ill individuals, pregnant women, subjects on hepatotoxic drugs such as antituberculous and antiretroviral drugs were excluded from the study.
Equipment used
An ultrasound machine ALOKA SSD-1000, (IP-1233EV, SN-57324, Japan) with curvilinear transducer with a frequency of 3.5MHz was used. Quality control maintenance check was routinely performed on the equipment by the medical physicist of the department prior to measurements. Measurements were carried out using the electronic calipers of the ultrasound machine after freezing the image.
Anthropometric parameters, like height, weight and body mass index of each participants were measured, Participants' heights were measured while standing against a meter rule with the head in Frankfurts' position after removing their shoes and their weight was measured using a weighing scale ZT WHO Scale to the nearest 0.1kg.
Scanning technique
The Ultrasound examination was carried out with the subjects in the supine and right anterior oblique position following an overnight fast. Subjects were exposed from the xiphisternum to the pelvic brim, ultrasound gel was applied to the right upper quadrants of the abdomen, and the transducer placed in the epigastrium in both the transverse and longitudinal planes to assess the main portal vein during quiet respiration, when the visualization of the portal vein was optimal, measurements were made at a point where the portal vein crosses anterior to the inferior vena cava (IVC) (fig. 1), with the calipers placed between the inner margins of the echogenic walls of the vessel. Measurements (in mm) were made twice by each of the two sonographers and the average values of the two measurements were recorded as the final value. Demographic data such as age, sex, weight, and height were recorded and the body mass index (BMI) was calculated using Quetelets' formula: BMI= weight (Kg)/height (m2)6.
Data analysis
Data capture sheet was used to record all the measurements obtained. Data analysis was done using Statistical Package for Social Science (SPSS) version 22.0 (SPSS Chicago, Illinois, USA). Descriptive statistics (mean, standard deviation, frequency, and percentages) and Pearson product moment correlation were used for the analysis. Statistical significance was considered at P<0.05.
Results
A total of 201 apparently healthy adults were enrolled for the study. The study constitutes 72 (35.82%) males and 129 (64.18%) females. The subjects were between the ages of 18–80 years, with mean age of 32.5±11.3 years. Participants within the age group of 25–29 years had the highest frequency of 15(7.46%), while those within the age group of 45–49 years had the lowest frequency of 3 (1.49%), as shown in table 1.
Table 1.
Frequency distribution base on age and sex of subjects.
| Age (YRS) |
Male N |
(%) | Female N |
(%) | Total N |
(%) |
| <20 | 5 | 2.49% | 14 | 6.97% | 19 | 9.45% |
| 21 – 24 | 6 | 2.99% | 19 | 9.45% | 25 | 12.44% |
| 25 – 29 | 15 | 7.46% | 34 | 16.92% | 49 | 24.38% |
| 30 – 34 | 14 | 6.97% | 24 | 11.94% | 38 | 18.91% |
| 35 – 39 | 12 | 5.97% | 14 | 6.97% | 26 | 12.94% |
| 40 – 44 | 5 | 2.49% | 12 | 5.97% | 17 | 8.46% |
| 45 – 49 | 3 | 1.49% | 5 | 2.49% | 8 | 3.98% |
| 50+ | 12 | 5.97% | 7 | 3.48% | 19 | 9.45% |
| 32.5±11.3 | 72 | 35.82% | 129 | 64.18% | 201 | 100% |
Participants within the age group of 45–49 years had the highest value of 10.50 ± 1.60mm and those within the age group 25–29 years had the least value of 9.12 ± 1.52mm as shown in table 2.
Table 2.
Distribution of mean PV diameter in relation to age.
| Age | Average PV DIAMETER (PVD) | |
| (Years) | (Mean ±STD) mm | |
| <20 | 9.42 ± 1.30 | |
| 21 – 24 | 9.12 ± 1.54 | |
| 25 – 29 | 9.12 ± 1.52 | |
| 30 – 34 | 9.95 ± 1.31 | |
| 35 – 39 | 9.69 ± 1.32 | |
| 40 – 44 | 9.24 ± 1.56 | |
| 45 – 49 | 10.50 ± 1.60 | |
| 50+ | 9.47 ± 1.26 | |
| Mean ± SD | 32.5±11.3 | 9.60 ± 1.41 |
The mean values of portal vein diameter in males and females were 9.71 ± 1.42mm and 9.53 ± 1.46 respectively, as shown in table 3
Table 3.
Mean PV diameter in relation to gender.
| Age | Male | Female PVD | |
| (YRS) | (MEAN±STD) mm | (MEAN±STD) mm | |
| <20 | 10.40 ± 1.14 | 9.07±1.21 | |
| 21 – 24 | 8.83 ± 0.98 | 9.21±1.69 | |
| 25 – 29 | 9.60 ± 1.18 | 8.91±1.62 | |
| 30 – 34 | 10.21 ± 1.67 | 9.79 ±1.06 | |
| 35 – 39 | 9.58 ± 1.56 | 9.79±1.12 | |
| 40 – 44 | 9.40 ±1.34 | 9.17 ±1.70 | |
| 45 – 49 | 10.33 ± 2.08 | 10.60±1.52 | |
| 50+ | 9.50 ± 1.38 | 9.43 ±1.13 | |
| (Mean ± SD) | 32.5±11.3 | 9.71 ± 1.42 | 9.35 ± 1.46 |
This study found the mean weight of 66.32 ± 10.65kg and the mean height of 1.66 ± 0.08m respectively with mean portal vein diameter of 9.60 ± 1.14mm. It also shows participants within the age group 45–49 years had the highest mean weight and height of 82.63 ± 18.26kg and 1.69 ± 0.08m respectively with mean portal vein diameter of 10.50 ± 1.60mm while the age group <20 years had the least mean weight and height of 55.21 ± 11.55kg and 1.63 ± 0.08 mm respectively with mean portal vein diameter of 9.42 ± 1.30mm. There was a positive correlation between the average portal vein diameter and weight, height for both sexes with correlation coefficients of 0.857 and P ≤ 0.005 and 0.794 and P ≤ 0.001 respectively as shown in table 4.
Table 4.
Participants weight, height and mean Portal Vein Diameter according to age group.
| Age | Weight | Height | Mean PVD | |
| (YEARS) | (MEAN±STD)kg | (MEAN±STD)m | (MEAN±STD) mm | |
| <20 | 55.21±11.55 | 1.63±0.08 | 9.42 ± 1.30 | |
| 21 – 24 | 58.44±13.79 | 1.65±0.10 | 9.12 ± 1.54 | |
| 25 – 29 | 61.49±13.74 | 1.64±0.11 | 9.12 ± 1.52 | |
| 30 – 34 | 69.61±15.27 | 1.65±0.11 | 9.95 ± 1.31 | |
| 35 – 39 | 74.19±16.79 | 1.66±0.08 | 9.69 ± 1.32 | |
| 40 – 44 | 64.82±10.99 | 1.63±0.09 | 9.24 ± 1.56 | |
| 45 – 49 | 82.63±18.26 | 1.69±0.08 | 10.50 ± 1.60 | |
| 50+ | 67.32±10.65 | 1.66±0.10 | 9.47 ± 1.26 | |
| Total | 32.5±11.3 | 66.32 ± 10.65 | 1.66±0.08 | 9.60±1.41 |
The mean portal vein diameter for both male and female participants with normal Body Mass Index was 9.77 ±1.41mm and 8.76 ± 1.37mm respectively. There was a positive correlation between the PV diameter and BMI of the participants (P ≤ 0.010) as shown in table 5 and figure 2.
Table 5.
Participants BMI and Average Portal Vein Diameter.
| BMI ( kg/m2) |
Male N (%) PVD |
Female N (%) PVD |
P-value |
| Underweight | |||
| (<18.50) | 8(3.98) 9.77 ± 1.41 | 21(10.25) 8.76 ± .37 | 0.047 |
| Normal | |||
| (18.50–24.50) | 49(24.38) 9.95 ± 1.41 | 45(22.39) 9.04 ± 1.43 | 0.043 |
| Overweight | |||
| (>25.0) | 15(7.46) 9.13±1.25 | 63(31.34) 9.76 ± 1.39 | 0.053 |
BMI classification was adapted from Pyrex Journal of Nursing and Midwifery6.
Discussion
Ultrasound imaging plays an important role in the assessment of the portal vein diameter, flow rate, and peak systolic velocity which gives an accurate and a reliable method of diagnosing disease conditions of the liver such as chronic liver diseases2,7.
The mean portal diameter in this study was 9.60 ± 1.41mm. Similar findings were reported by other studies in Nigeria; Usman et al7, found 10.87±0.81mm in North-Eastern Nigeria, Ukperi8 and Adeyekun et al5 in south western Nigeria found 8.1±0.12mm and 10.3±1.5mm respectively. Anakwue et al9 in South Eastern Nigeria found 11.5±1.5mm as the mean portal vein diameter. This similarity in the reported portal vein diameter could be due to the similarities in the methods adopted by these studies as the measurements were all done using the trans-abdominal approach and using similar probe frequencies.
However, studies conducted in other countries also report similar findings. Ongoiba et al10 in Bamako, Mali reported a mean value of 9.2±2.6mm. Hawaz et al2 among Ethiopians reported a mean value of 10.0±1.8mm, Webb et al11 reported mean portal vein diameter of 6.3±2.3mm, Weinerb et al12 in USA reported a mean value of 11±2.0mm, Rokni-Yazdi et al13 in Iran, reported a mean value of 9.36±1.65mm, Bhattacharya et al1 in West Bengal, India reported a mean value of 10.02±0.89mm. The reported values of the PV diameter from studies from other countries and among different ethnic groups and races, with varying samples sizes, did not vary with the values obtained from our study. This implies that using similar methodology and equipment in the hands of a qualified sonographer and /or sonologist, the measurement of the portal vein diameter can be reproducible and reliable.
However, one of the limitations of this present study is that only the diameter of the portal vein was measured and not the portal flow which was also assessed by Rokni-Yazdi et al13
Some literature haSdocumented portal vein diameter to vary with age, gender, and Body Mass Index. The mean portal vein diameter among males in this study was higher than females, being 9.71±1.42mm and 9.35±1.46mm respectively. The difference is not statistically significant (p<0.05). This is in agreement with the reports of Hawaz et al2, Gosh et al3, Adeyekun et al5, Siddiqui et al14, Saha et al15 and Goyal et al16 who found no significant influence of gender on portal vein diameter. This similarity may be attributed to larger number of females participants in volved in the studies. Moreover, the influence of age on portal vein diameter has been documented by various researchers with varied results. This study showed positive correlation of age with portal vein diameter (p<0.01). This is in line with the study of Bhattacharya et al1, Hawaz et al2, Gosh et al3, Anakwue et al9, Weinreb et al12, Saha et al15 and Patriquin et al17. It however contradicts the findings of Adeyekun et al5 who reported there was no statistically significant influence of age on portal vein diameter. This variation in the portal vein diameter may be attributed to difference in the phase of respiration at the time of ultrasonographic measurements.
This study also showed a positive correlation between Body Mass Index (BMI) and portal vein diameter (p<0.01). This is in agreement with the reports of Saha et al15 andGosh et al3. However, it was in contrast to the findings of Adeyekun et al5 who reported that there was no statically significant influence of BMI on portal vein diameter. The difference in the reported value may be attributed to the sedentary life style in the Western part of Nigeria compared to the nomads in northern Nigeria who are either farming, grazing or leaving an active life. Rajashree et al18 also reported a positive correlation between the portal vein diameter and other anthropometric parameters. The knowledge of these normal variations is essential for surgeons, sonologist and sonographers during diagnosis of problems that may relate to the portal system.
Conclusion
This study has established baseline values for normal range of portal vein diameter in apparently healthy adults in a Northern Nigerian population to be 9.60 ± 1.41mm and also found that PV diameter positively correlates with anthropometric variables.
Acknowledgement
We acknowledge the Head of Department of Radiology Dr Yusuf Aliyu, and other staff of the department of Radiology ATBU, Bauchi for their support during data collection.
Authors' contribution
GL: Participated in conceptualization and design of the work, data acquisition, analysis, manuscript drafting, revi sion for its intellectual content and approval of the final work.
MS: Participated in conceptualization and design of the work, data acquisition, analysis, manuscript drafting, revi sion for its intellectual content and approval of the final work.
DZJ: Participated in data acquisition, manuscript drafting, revision for its intellectual content and approval of the final work.
NCI: Participated in conceptualization and design of the work, revision for its intellectual content and approval of the final work.
SHG: Participated in conceptualization and design of the work, revision for its intellectual content and approval of the final work.
References
- 1.Bhattacharya J, Aditi D, Anish B. Sonographical Assessment of Portal vein diameter in northern part of West Bengal. India oct Jour Env Res. 2013;1(3):231–234. PubMed. [Google Scholar]
- 2.Hawaz Y, Admassie D, Kebede T. Ultrasound Assessment of Normal Portal Vein Diameter in Ethiopians Done at Tikur Anbessa Specialized Hospital. East Cent Afr J Surg. 2012;17(1):90–93. PubMed. [Google Scholar]
- 3.Ghosh TN, Bernerjee M, Basu S, Das R, et al. Assessment of normal portal vein diameter in children. Journal of Tropical Gastroentrology. 2014;35(2):79–84. [PubMed] [Google Scholar]
- 4.Mandal L, Mandal SK, Bandyopadhyay D, Datta S. Correlation of portal vein diameter and splenic size with gastro-oesophageal varices in cirrhosis of liver. Journal, Indian Academy of Clinical Medicine. 2011;12(4):266–270. [Google Scholar]
- 5.Adeyekun AA, Tsebi HB. Grey Scale Sonographic-Assessment of Portal Vein Diameter in Healthy Nigerian Adults. Journal of Medicine and Biomedical Research. 2014;13(1):17–24. [Google Scholar]
- 6.Huxley R, Mendis S, Zheleznyakov E, Reddy S, Chan J. Body mass index, waist circumference and waist: hip ratio as predictors of cardiovascular risk - a review of the literature. European Journal of Clinical Nutrition. 2010;64:16–22. doi: 10.1038/ejcn.2009.68. [DOI] [PubMed] [Google Scholar]
- 7.Usman AU, Ibinaiye P, Ahidjo A, Tahir A, Sa'ad ST, et al. Ultrasound Determination of Portal Vein Diameter in Adult Patients with Chronic Liver Disease in North-Eastern Nigeria. Sub-Saharan Afr J Med. 2015;2(2):57–63. [Google Scholar]
- 8.Ukperi OS. Ultrasonographic measurement of normal portal vein diameter in Nigerian adults. 2010 Dissertation submitted to the faculty of radiology, West African college of surgeons. [Google Scholar]
- 9.Anakwue AC, Anakwue RC, Ugwu AC, et al. Sonographic evaluation of normal portal Vein diameter in Nigerians. European Journal of scientific research. 2009;36(1):114–117. [Google Scholar]
- 10.Ongoiba N, Sissoko F, Ouologuen I, Berete S, Traore AK. Portal vein sonographic anatomy. Morphologie. 2003;87:29–32. PubMed. [PubMed] [Google Scholar]
- 11.Webb LJ, Berger A, Sherlock S. Grey Scale ultrasonography of the portal vein. Lancet. 1977;2:675–667. doi: 10.1016/s0140-6736(77)90492-5. [DOI] [PubMed] [Google Scholar]
- 12.Weinreb J, Kumari S, Phillips G, Pochaczevsky R. Portal vein measurement by realtime sonography. Am J Roentgenology. 1982;139:497–499. doi: 10.2214/ajr.139.3.497. [DOI] [PubMed] [Google Scholar]
- 13.Rokni-Yazdi H, Sotoudeh H. Assessment of Normal Doppler Parameters of Portal Vein and Hepatic Artery in 37 Healthy Iranian Volunteers. Iran J Radiol. 2006;3(4):213–216. [Google Scholar]
- 14.Siddiqui TR, Hassan N, Gul P. Effect of anthropometric measurements on portal vein and hepatosplenic span. Pak J Med Sci. 2013;29(4):1077–1080. doi: 10.12669/pjms.294.3617. PubMed. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 15.Saha N, Sarkar R, Singh MM. Portal vein diameter in a tertiary care centre in North-East India. Journal of Dental and Medical Sciences. 2015;14(12):110–113. [Google Scholar]
- 16.Goyal AK, Pokharna DSS, Sharma SK. Ultrasonic measurement of portal vasculature in the diagnosis of portal hypertension. A controversial subject reviewed. J Ultrasound Med. 1990;9:45–48. doi: 10.7863/jum.1990.9.1.45. [DOI] [PubMed] [Google Scholar]
- 17.Partriquin HB, Peareault G, Gignon L, Boisvert J, Filiatrant D, et al. Normal portal venous diameter in children. Paed Radiol. 1990;20:451–453. doi: 10.1007/BF02075206. [DOI] [PubMed] [Google Scholar]
- 18.Raut Rajashree Sheelawant, Bahetee B H. Study of Anatomical Dimensions of Portal Vein. Sch J App Med Sci. 2015;3(3E):1343–1345. [Google Scholar]