A handy tool to teach segmental liver anatomy to surgical trainees

Information Entropy and Its Applications

Ultrasound is a first-line diagnostic tool for imaging many disease states. A number of statistical distributions have been proposed to describe ultrasound backscattering measured from tissues having different disease states. As an example, in this chapter we use nonalcoholic fatty liver disease (NAFLD), which is a critical health issue on a global scale, to demonstrate the capabilities of ultrasound to diagnose disease. Ultrasound interaction with the liver is typically characterized by scattering, which is quantified for the purpose of determining the degree of liver steatosis and fibrosis. Information entropy provides an insight into signal uncertainty. This concept allows for the analysis of backscattered statistics without considering the distribution of data or the statistical properties of ultrasound signals. In this chapter, we examined the background of NAFLD and the sources of scattering in the liver. The fundamentals of information entropy and an algorithmic scheme for ultrasound entropy imaging are then presented. Lastly, some examples of using ultrasound entropy imaging to grade hepatic steatosis and evaluate the risk of liver fibrosis in patients with significant hepatic steatosis are presented to illustrate future opportunities for clinical use.

Considerations of Ultrasound Scanning Approaches in Non-alcoholic Fatty Liver Disease Assessment through Acoustic Structure Quantification

Non-alcoholic fatty liver disease (NAFLD) is a risk factor for hepatic fibrosis and cirrhosis. Acoustic structure quantification (ASQ), based on statistical analysis of ultrasound echoes, is an emerging technique for hepatic steatosis diagnosis. A standardized measurement protocol for ASQ analysis was suggested previously; however, an optimal ultrasound scanning approach has not been concluded thus far. In this study, the suitability of scanning approaches for the ASQ-based evaluation of hepatic steatosis was investigated. Hepatic fat fractions (HFFs; liver segments VIII, III and VI) of 70 living liver donors were assessed with magnetic resonance spectroscopy. A clinical ultrasound machine equipped with a 3-MHz convex transducer was used to scan each participant using the intercostal, epigastric and subcostal planes to acquire raw data for estimating two ASQ parameters (C_m² and focal disturbance [FD] ratio) of segments VIII, III and VI, respectively. The parameters were plotted as functions of the HFF for calculating the values of the correlation coefficient (r) and probability value (p). The diagnostic performance of the parameters in discriminating between the normal and steatotic (≥5 and ≥10%) groups was also compared using receiver operating characteristic (ROC) curves. The C_m² and FD ratio values measured using the epigastric and subcostal planes did not correlate with the severity of hepatic steatosis. However, intercostal imaging exhibited a higher correlation between the ASQ parameters and HFF (r = -0.64, p < 0.001). The diagnostic performance of C_m² and FD ratio in detecting hepatic steatosis using intercostal imaging was also satisfactory (areas under ROC curves >0.8). Intercostal imaging is an appropriate scanning approach for ASQ analysis of the liver.

A Game-Based Approach to Teaching and Learning Anatomy of the Liver and Portal Venous System

Introduction

The use of games and game elements as teaching tools has received increasing attention in the medical education literature. Used formatively, games promote student engagement and satisfaction, and encourage collaboration and teamwork among students. They may also help students retain knowledge, although research supporting this notion is limited. This resource contains a 30-minute interactive lab station involving two different game-based activities aimed at teaching functional anatomy of the liver and portal venous system.

Methods

The first activity is a flipped version of a traditional pinned anatomy practical, wherein students place their own pins on a body donor in response to application-level prompts. The second activity is an outlay-type card game where students assemble cards to depict the venous drainage of gut organs in a healthy patient versus one with portal hypertension.

Results

In end-of-session reviews, several students volunteered feedback that the activities were effective and enjoyable. Additionally, average student scores on two subject exam questions increased by approximately 13% and 4%, compared with students who took the exam before the game elements were introduced.

Discussion

These game-based activities may serve as a starting point for others wishing to deal with historically difficult topics in a more engaging way. The tools presented are low-cost, low-tech, and easy to modify for use with different student populations.

The "Triple-Q Algorithm:" A practical approach to the identification of liver topography

The descriptive identification and interpretation of liver pathology continue to raise debate, especially for trainees and junior physicians. There is wide diversity in the description of liver segmentation with sometimes contradictory terminology between French and American literature. Attempts were made to create a unified nomenclature that simplifies the problem. We propose a simple approach to describe the location of liver pathology in different settings by referring to an algorithm based on three questions. Explanations to answer these questions and correctly describe the location of liver pathology are herein described. In conclusion, we think that the adoption of such an algorithm called arbitrary “the Triple-Q Algorithm” will facilitate the understanding of liver topography for the young physicians, as well as it will allow for the accurate description and localization of the pathological lesions in the liver. This could be achieved after testing and validating this algorism in prospective studies. This could have academic and clinical implications in the medical education and the patient care.

Clinical and surgical anatomy of the liver: a review for clinicians

The liver is the largest gland in the body occupying 2.5% of total body weight and providing a host of functions necessary for maintaining normal physiological homeostasis. Despite the complexity of its functions, the liver has a homogenous appearance, making hepatic anatomy a challenging topic of discussion. To address this issue, scholars have devoted time to establishing a framework for describing hepatic anatomy to aid clinicians. Work by the anatomist Sir James Cantlie provided the first accurate division between the right and left liver in 1897. The French surgeon and anatomist Claude Couinaud provided additional insight by introducing the Couinaud segments on the basis of hepatic vasculature. These fundamental studies provided a framework for medical and surgical discussions of hepatic anatomy and were essential for the advancement of modern medicine. In this article, the authors review the normal anatomy and physiology of the liver with a view to enhancing the clinician's knowledge base. They also provide a convenient model to assist with understanding and discussion of liver anatomy.