Ultrasound Measurements of Hepatic Vasculatures and Hepatic Doppler Assessment of Healthy Children

Study Overview
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Brief Summary
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Flow dynamics in the liver is altered in different hepatobiliary and cardiac pathologies, causing changes in hepatic vasculatures sizes and flow pattern changes which can be assessed by ultrasound (USG) study. Before one can use these measurements and observations to diagnose pathologies, a clear grasp of normality is crucial. In the field of pediatrics, this is particularly challenging as the normal range of measurements may change with age, weight, height, gender and race of children. Taking hepatic veno-occlusive disease as an example, current literature is conflicting regarding whether sonographic findings show consistent association with the disease. Sonographic findings therefore now have limited role in contributing to the diagnosis. This may be related to the lack of a robust age corrected normal range of measurement for reference. Existing literature shows that the normal portal vein diameter varies with age, weight and height and possibly gender. Literature for normal measurements of hepatic vein and hepatic artery in children is lacking. In this study, the investigators aim to conduct a prospective, cross-section observational study to establish the normal measurements ranges of hepatic vein, hepatic artery and portal vein in healthy children in the investigators' locality. Flow patterns, including qualitative assessment and quantitative measurements of resistive index and flow velocities will also be assessed. These age corrected normal measurements will be very helpful in the diagnosis and follow-up of hepatobiliary and cardiac pathologies associated with alterations in dynamics of hepatic circulation.

Detailed Description
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Trial Objectives and Purpose: To establish normal limits of diameter of hepatic vein, hepatic artery and portal vein according to age, weight, height and gender. To establish normal waveform pattern in ultrasound Doppler assessment of hepatic vein, hepatic artery and portal vein. (Qualitative analysis) To establish normal limits of flow parameters assessed by ultrasound Doppler in hepatic vein, hepatic artery and portal vein according to age, weight, height and gender. Trial Design: A prospective cross-section observational study. Recruitment of study subjects: Patients attending Hong Kong Children's Hospital for clinically indicated USG examination will be invited to participate in this study under specific inclusion and exclusion criteria. Treatment of subjects: Recruited subjects will proceed to the clinically indicated USG study they are referred for first. After the clinically indicated USG study is completed, additional USG & Doppler assessment of hepatic vasculatures will be performed, taking an additional 5 - 10 minutes. All examinations will be done using a Philips EPIQ 5G ultrasound machine. Curvilinear or linear probe will be used depending on subjects' physique. Size measurements, qualitative and quantitative Doppler assessment of hepatic vein, hepatic artery and portal vein will be made and recorded. Statistical method to be employed: Continuous variables will be tested for normality by Shapiro-Wilk's test. Simple statistics including mean and standard deviations (+/- 2 SD) will be used to determine normal ranges for age. Comparisons will be done by student's t-test. Relations between height, weight and gender with vessels diameter will be tested by Pearson correlation. Linear multiple regression analysis will be utilized with vessels diameter as the dependent variable. Number of subject to be enrolled (observation study): 300 Rationale: Sample size = (Standard normal variate)2 X (Standard deviation)2 / Presicion2 Sample size = 1.962 X 22 / 12 Sample size = 15.37 Standard normal variate = 1.96 at 5% Type I error Standard deviation = up to 2mm (from prior study of portal vein diameter) Precision = 1mm In view of aim of determining age corrected normal range of vessels diameter in children, a much bigger sample size will be obtained to improve accuracy. Target to include 300 children in this study. Age groups: Around 30 cases for each of the following age groups: 0 - 1 years old 1 - 2 years old 2 - 4 years old 4 - 6 years old 6 - 8 years old 8 - 10 years old 10 - 12 years old 12 - 14 years old 14 - 16 years old 16- 18 years old

Official Title
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Ultrasound Measurements of Hepatic Vasculatures and Hepatic Doppler Assessment of Healthy Children

Conditions
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Portal Vein, Hepatic Veins, Hepatic Artery, Liver Circulation

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patient < / = 18 years of age. No history of hepatobiliary nor cardiac pathology as checked with record in ePR. Verbal confirmation will be done with patient or parent / legal guardian. Attending USG study other than that of the hepatobiliary system. (ie. Patients attending for thyroid USG, urinary system USG, musculoskeletal system USG etc.) Exclusion Criteria: Patient > 18 years of age Known history of hepatobiliary or cardiac pathology. Unstable patients. Intolerance of USG examination Uncooperative patients. Patient requiring sedation for USG study.

Ages Eligible for Study
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Minimum Age: 1 Day
Maximum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Hepatic veins diameter (in mm) measured by grey scale ultrasound at 1 - 2 cm from confluence with inferior vena cava | Right, middle and left hepatic vein diameter (in mm) measured by grey scale Ultrasound at location 1 - 2 cm from confluence with inferior vena cava, measured in longitudinal axis | Baseline | 
| Hepatic veins Doppler assessment of flow direction (towards or away from inferior vena cava) | Ultrasound Doppler assessment of right, middle and left hepatic veins for flow direction (towards or away from inferior vena cava) | Baseline | 
| Hepatic veins Doppler assessment of flow pulsatility (yes or no) | Ultrasound Doppler assessment of right, middle and left hepatic veins for flow pulsatility (yes or no) | Baseline | 
| Hepatic veins Doppler assessment of flow phasicity (monophasic, biphasic or triphasic) | Ultrasound Doppler assessment of right, middle and left hepatic veins for flow phasicity (monophasic, biphasic or triphasic) | Baseline | 
| Hepatic veins Quantitative Doppler measurement of maximum flow rate (cm/s) | Ultrasound Doppler quantitative measurement of right, middle and left hepatic veins maximum flow rate (cm/s) | Baseline | 
| Hepatic veins Quantitative Doppler measurement of minimum flow rate (cm/s) | Ultrasound Doppler quantitative measurement of right, middle and left hepatic veins minimum flow rate (cm/s) | Baseline | 
| Hepatic veins Quantitative Doppler measurement of pulsatility index (only if pulsatility is present) | Ultrasound Doppler quantitative measurement of right, middle and left hepatic veins pulsatility index (Only if pulsatility is present) | Baseline | 
| Hepatic artery diameter (in mm) measured by grey scale ultrasound at liver hilum | Hepatic artery diameter (in mm) measured by grey scale ultrasound at the hepatic hilum (longitudinal axis) | Baseline | 
| Hepatic artery Doppler assessment of flow direction (hepatofugal or hepatopetal) | Ultrasound Doppler assessment of hepatic artery flow direction (hepatofugal or hepatopetal) | Baseline | 
| Hepatic artery Doppler assessment of flow pulsatility (yes or no) | Ultrasound Doppler assessment of hepatic artery flow pulsatility (yes or no) | Baseline | 
| Hepatic artery Doppler assessment of flow phasicity (monophasic, biphasic or triphasic) | Ultrasound Doppler assessment of hepatic artery flow phasicity (monophasic, biphasic or triphasic) | Baseline | 
| Hepatic artery quantitative Doppler measurement of peak systolic velocity (cm/s) | Ultrasound Doppler quantitative measurement of hepatic artery peak systolic velocity (cm/s) | Baseline | 
| Hepatic artery quantitative Doppler measurement of end diastolic velocity (cm/s) | Ultrasound Doppler quantitative measurement of hepatic artery end diastolic velocity (cm/s) | Baseline | 
| Hepatic artery quantitative Doppler measurement of pulsatility index | Ultrasound Doppler quantitative measurement of hepatic artery pulsatility index | Baseline | 
| Hepatic artery quantitative Doppler measurement of resistive index | Ultrasound Doppler quantitative measurement of hepatic artery resistive index | Baseline | 
| Hepatic artery quantitative Doppler measurement of flow volume (ml/s) (measured if feasible) | Ultrasound Doppler quantitative measurement of hepatic artery flow volume (ml/s) | Baseline | 
| Portal vein diameter (in mm) measured by grey scale ultrasound at liver hilum | Portal vein diameter (in mm) measured by grey scale ultrasound at liver hilum (longitudinal axis) | Baseline | 
| Portal vein Doppler assessment of flow direction (hepatopetal or hepatofugal) | Ultrasound Doppler assessment of portal vein flow direction (hepatopetal or hepatofugal) | Baseline | 
| Portal vein Doppler assessment of flow pulsatility (yes or no) | Ultrasound Doppler assessment of portal vein pulsatility (yes or no) | Baseline | 
| Portal vein Doppler assessment of flow phasicity (monophasic, biphasic or triphasic) | Ultrasound Doppler assessment of portal vein flow phasicity (monophasic, biphasic or triphasic) | Baseline | 
| Portal vein quantitative Doppler measurement of maximum flow rate (cm/s) | Ultrasound Doppler quantitative measurement of portal vein maximum flow rate (cm/s) | Baseline | 
| Portal vein quantitative Doppler measurement of minimum flow rate (cm/s) | Ultrasound Doppler measurement of portal vein minimum flow rate (cm/s) | Baseline | 
| Portal vein quantitative Doppler measurement of pulsatility index (only if pulsatility is present) | Ultrasound Doppler quantitative measurement of portal vein pulsatility index | Baseline | 
| Portal vein quantitative Doppler measurement of flow volume (ml/s) | Ultrasound Doppler measurement of portal vein flow volume (ml/s) | Baseline |