SONOGRAPHIC EVALUATION OF NORMAL GALLBLADDER AND CHOLECYSTITIS

SONOGRAPHIC EVALUATION OF NORMAL GALLBLADDER AND CHOLECYSTITIS

1. A SIWES PRESENTATION ON SONOGRAPHIC EVALUATION OF NORMAL GALLBLADDER AND CHOLECYSTITIS UNDERTAKEN AT FEDERAL MEDICAL CENTER, MAKURDI BY AMAMA JANET ELU 22/ANA/061 SUBMITTED TO DEPARTMENT OF HUMAN ANATOMY AND FORENSIC ANTHROPOLOGY UNIVERSITY OF CROSS RIVER STATE OKUKU CAMPUS

2. OUTLINE Introduction Ultrasound Transducer Patient Preparation Normal Ultrasound Appearance Acute Cholecystitis Summary References

3. INTRODUCTION T he gallbladder is a small, pear-shaped organ situated in the gallbladder fossa on the inferior (visceral) surface of the right lobe of the liver. Anatomical Parts: Fundus Body Infundibulum / Hartmann's Pouch Neck Cystic Duct The gallbladder's primary role is to store and concentrate bile. Bile, which is produced by the liver, is composed of water, bile salts, bilirubin, and cholesterol which aids in digestion . Biliary tree: Cystic duct, common hepatic duct, common bile duct. Liver, Gall Bladder and Stomach Source:https ://www.researchgate.net/figure/Anatomy-KM_fig1_331991854

4. INTRODUCTION Ultrasound is the initial imaging modality for evaluating the gallbladder due to its numerous advantages over other methods. Its high accuracy, combined with its safety, accessibility, and cost-effectiveness, makes it the preferred first-line diagnostic tool It has a high sensitivity and specificity for detecting common gallbladder pathologies, such as: Gallstones (cholelithiasis ) Gallbladder inflammation (cholecystitis): Polyps and tumors :

5. ULTRASOUND TRANSDUCER Ultrasound imaging uses high-frequency sound waves. A transducer sends these sound waves into the body. When the waves encounter different tissues (e.g., fluid, soft tissue, stone), they reflect as echoes . The transducer receives these echoes, and the ultrasound machine processes them into a real-time image. Curvilinear Transducer Source:https ://www.shutterstock.com/search/probe-ultrasound

6. ULTRASOUND TRANSDUCER Anechoic (black) areas indicate no echoes Hypere chogenic (white) areas indicate strong echoes Hypoechogenic (grey) areas indicate moderate echoes Curvilinear Array Transducer (2-5 MHz): This is the primary transducer for most abdominal examinations. Its lower frequency allows for deeper penetration , enabling visualisation of the gallbladder and its relationship to the liver and surrounding structures. It provides a wide field of view, ideal for surveying the entire organ. Different shades on Ultrasound Source: https://aneskey.com/of-ultrasound-guidance

7. PATIENT PREPARATION Fasting is Key The patient must fast for a minimum of 6 to 8 hours before the exam. Why it's essential: It allows the gallbladder to be maximally distended with bile, making it easier to visualise the gallbladder . It prevents post-prandial contraction, which can cause physiological wall thickening that mimics pathology. (Note: Lack of fasting is a common cause of a suboptimal exam.)

8. PATIENT PREPARATION Standard Patient Positioning: Supine Position: The initial and most common position. The patient lies flat on their back. The transducer is placed subcostally or intercostally to visualize the gallbladder in both longitudinal and transverse planes.

9. NORMAL ULTRASOUND APPEARANCE Longitudinal T he gallbladder appears as an elongated, oval or pear-shaped structure. The fundus is typically the most infe rior and rounded portion. The neck is the tapered superior portion, connecting to the cystic duct. Lumen: The inside of the gallbladder should be completely anechoic (black). F luid -filled structure, containing bile. There should be no internal echoes or sediment .

10. NORMAL ULTRASOUND APPEARANCE Gallbladder Wall: The wall appears as a thin, uniform, and brightly echogenic (white) line. The normal wall thickness is a crucial measurement and should be less than 3 mm. The wall should have a smooth, well-defined contour.

11. NORMAL ULTRASOUND APPEARANCE Transverse View: When the transducer is rotated 90 degrees, the gallbladder appears as a round or oval anechoic structure. This view is crucial for surveying the entire lumen for stones . Key Measurements The most important measurement in gallbladder sonography is the wall thickness. Normal Wall Thickness is < 3 mm. Normal AP Diameter is <4cm. Both measurements should be taken in the transverse view. Transverse view of the GB Source: https://radiologykey.com/the-gallbladder-and-biliary-system

12. ACUTE CHOLECYSTITIS Cholecystitis is defined as inflammation of the gallbladder. It is a serious condition that usually requires immediate medical attention and often surgery. Causes: Calculous Cholecystitis (90-95%): It occurs when a gallstone blocks the gallbladder neck or the cystic duct, obstructing the outflow of bile. Acalculous Cholecystitis (5-10%): This occurs when the gallbladder becomes inflamed without the presence of gallstones. Inflammed gallbladder(transverse and longitudinal) Source:https ://www.researchgate.net/figure/U-S-of-abdomen-showing-the-thickened-gallbladder-wall_fig1_258381850

13. ACUTE CHOLECYSTITIS The Sonographic "Big 4" of Acute Cholecystitis Gallstones: Hyperechoic (bright) foci within the gallbladder lumen.posterior acoustic shadow Gallbladder Wall Thickening: The wall appears thickened(>3 mm) Pericholecystic Fluid : A small rim of anechoic (black) fluid surrounding the gallbladder. Sonographic Murphy's Sign: It is defined as focal tenderness and pain directly over the gallbladder when compressed with the ultrasound transducer. “Big 4” on Acute Cholecystitis Source:https ://www.lumen.luc.edu/lumen/meded/radio/curriculum/surgery/cholecystitis.htm

14. ACUTE CHOLECYSTITIS GALLSTONES: On an ultrasound, gallstones appear as hyper echogenic foci within the anechoic (black) bile of the gallbladder. Their appearance is a combination of some key sonographic features: Posterior Acoustic Shadowing Gravity Dependence and Mobility

15. ACUTE CHOLECYSTITIS Gallbladder Wall Thickening Pathological vs. Physiological Thickening: Pathological: Caused by inflammation (cholecystitis). The wall appears edematous, often hypoechoic (darker). Physiological: Caused by gallbladder contraction (after eating). The wall appears uniformly thickened, and the lumen is small. The Crucial Measurement: As stated, a normal wall is <3 mm. A wall measuring >3 mm is the key sonographic marker of inflammation. Measurement Technique: The measurement should be taken in the transverse plane on the anterior wall of the gallbladder. Place calipers from the outer wall to the inner wall.

16. ACUTE CHOLECYSTITIS Pericholecystic Fluid: Appearance: A thin, crescent-shaped, anechoic (black) fluid collection that surrounds the gallbladder. Significance: It represents inflammatory fluid or exudate that has leaked from the acutely inflamed gallbladder wall into the surrounding gallbladder fossa. Localization: It is most commonly seen in the liver-gallbladder interface, often best viewed in the transverse plane.

17. SUMMARY Ultrasound is the first-line imaging modality for evaluating the gallbladder . A systematic approach is essential. Always begin by confirming patient fasting, and then systematically evaluate the gallbladder's size, wall thickness, internal contents, and surrounding structures. Diagnosis requires a combination of findings. A diagnosis of acute cholecystitis is not made by a single sign, but by correlating multiple sonographic findings (stones, thickened wall, pericholecystic fluid) with the patient's clinical presentation (pain, fever) and lab results.

18. SUMMARY Knowing the variants is critical. Be aware of normal anatomical variants and common pitfalls (like a non-fasting gallbladder) to avoid misdiagnosis. The dynamic nature of ultrasound allows for real-time confirmation of findings, such as the mobility of stones and the presence of a sonographic Murphy's sign.

19. REFERENCES Bates, L., Szilagyi , P., and Bickley, L. (2017). Bates' Guide to Physical Examination and History Taking. 12th edn . Philadelphia, PA: Lippincott Williams & Wilkins. Levine, D., Rumack , C. M. and Waser , M. N. (2018). Diagnostic Ultrasound. 5th edn . Philadelphia, PA: Elsevier. Middleton, W. D. (2011). ACR–AIUM Practice Guideline for the Performance of an Ultrasound Examination of the Gallbladder and Biliary Tract. Reston, VA: American College of Radiology. Feldman, M., Friedman, L. S. and Brandt, L. J. (2015). Sleisenger and Fordtran's Gastrointestinal and Liver Disease: Pathophysiology, Diagnosis, Management. 10th edn . Philadelphia, PA: Saunders. Gore, R. M. and Levine, M. S. (2015). Textbook of Gastrointestinal Radiology. 4th edn . Philadelphia, PA: Saunders. Tee, G. and Ahamed, M. (2018). Ultrasound Guided Injections. 1st edn . Oxford: Oxford University Press.

20. THANK YOU FOR YOUR RAPT ATTENTION