Normal Range of Superior Mesenteric Artery in Young Chinese Population and Its Correlation With Retroperitoneal Adipose Tissue

Study Overview
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Brief Summary
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In literature, superior mesenteric artery (SMA) angle, also named as aortomesenteric angle (AMA), varies greatly in both adult and children; while the aortomesenteric distance also ranges widely. Both AMA and AMD are influenced by retroperitoneal fat. Decrease of AMA and AMD may lead to the superior mesenteric artery syndrome(SMAS), which is a rare medical condition mainly presenting with duodenum obstruction. To our knowledge, normal range of AMA and AMD in local young Chinese population remain unclear; on the other hand, there have only a few studies exploring the relationship between them. This project proposes to establish the normal range of AMA and AMD in local young Chinese population, and to further investigate how the retroperitoneal adipose tissue correlates with AMA and AMD. The normal range obtained in this proposed study will provide more specific reference value to distinguish abnormal AMA and AMD, and to improve the diagnosis accuracy of SMAS in local population. Moreover, this study will provide deeper insight concerning the impact of retroperitoneal fat on AMA and AMD.

Official Title
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Normal Range of Superior Mesenteric Artery on Computerized Tomography in Young Chinese Population and Its Correlation With Retroperitoneal Adipose Tissue

Conditions
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Aortomesenteric Angle, Aortomesenteric Distance, Retroperitoneal Adipose Tissue

Intervention / Treatment
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* Diagnostic Test: computerized tomography


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: With age range of 10-35 years old. Chinese ethnicity. With abdomen contrast CT. Exclusion Criteria: Any patients with diagnosis of SMAS will be excluded from the Non-SMAS group. Patients who had undergone more than one CT scan during the research period. Previous retroperitoneal, abdominal surgery. Conditions causing significant weight loss, e.g. anorexia nervosa, malabsorption. Presence of abdominal masses or pathology that will affect the anatomy of aorta- superior mesenteric artery and the retroperitoneal structures. Presence of severe scoliosis and/or history of spinal fixation that may increase incidence of SMA syndrome. Presence of free intraperitoneal or retroperitoneal fluid that may affect fat measurement, e.g. following trauma, or ascites.

Ages Eligible for Study
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Minimum Age: 10 Years
Maximum Age: 35 Years

Sexes Eligible for Study
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All

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Non-SMAS group<br>subjects in this group are not clinically diagnosed as superior mesenteric artery syndrome(SMAS). | Diagnostic Test: computerized tomography<br>* abdomen contrast computerized tomography performed for both emergency and elective purposes in HK public hospitals.<br>|
| SMAS group<br>subjects in this group are clinically diagnosed as superior mesenteric artery syndrome(SMAS). | Diagnostic Test: computerized tomography<br>* abdomen contrast computerized tomography performed for both emergency and elective purposes in HK public hospitals.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| aortomesenteric angle (AMA) | aortomesenteric angle in degree measured on sagittal CT image | 2 years | 
| aortomesenteric distance (AMD) | aortomesenteric distance in millimeter(mm) on axial CT image | 2 years | 
| visceral fat area | visceral fat area in square centimeter(cm2) evaluated by image post-processing software | 2 years | 
| subcutaneous fat area | subcutaneous fat area in square centimeter(cm2) evaluated by image post-processing software | 2 years | 
| area ratio of visceral fat to subcutaneous fat | area ratio in percentage(%) | 2 years | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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aortomesenteric angle, aortomesenteric distance, retroperitoneal adipose tissue, computerized tomography, young Chinese population