Cholecystitis and Gallstones: Real-Time Diagnosis with Ultrasound

Dr. Segnini
Jan 6
4 min read

Dr. Segnini Gallstones on ultrasound diagnosis

Pain in the Upper Right Quadrant

Acute abdominal pain in the right upper quadrant is one of the most frequent reasons for visits to the emergency department. Two of its main causes are closely related: cholelithiasis (gallstones) and acute cholecystitis (inflammation of the gallbladder) . Abdominal ultrasound is the imaging method of choice and the gold standard for evaluating the gallbladder and bile ducts, thanks to its ability to provide a rapid, accurate, and radiation-free diagnosis.

Why is ultrasound the technique of choice?

Ultrasound is ideal for visualizing the gallbladder and its pathologies due to several key characteristics:

High Resolution for Liquid Structures: The gallbladder filled with bile (a liquid) acts as a perfect "acoustic window", allowing its contents and walls to be seen clearly.
Immediacy and Dynamism: It can be performed in the same emergency room in minutes, evaluating the response to pain with the pressure of the transducer.
Excellent Sensitivity and Specificity: Close to 95% for detecting gallstones and signs of cholecystitis.
Comprehensive Evaluation: It not only examines the gallbladder, but also the bile ducts, liver, and pancreas, making a differential diagnosis.
Safety: It does not use radiation, allowing for repeated use if necessary.

Ultrasound Findings of Cholelithiasis (Gallstones)

Gallstones are the most common gallbladder pathology. Their diagnosis by ultrasound is based on two physical principles:

Hyperechoic (Bright) Structure : Gallstones, composed mainly of cholesterol or calcium bilirubinate , reflect ultrasound almost completely, appearing as intensely bright ( hyperechoic ) structures within the gallbladder.
Posterior Acoustic Shadow: Because the stone absorbs and reflects sound, a conical area of absence of echoes (black) is generated behind it , known as an acoustic shadow. The combination of a mobile hyperechoic focus with an acoustic shadow is diagnostic of gallstones.
Other related findings:
- Biliary Sludge : Appears as a hypoechoic or isoechoic (gray) material, non-motile or slowly mobile , occupying the dependent portion of the gallbladder, without generating acoustic shadowing. It is a precursor to gallstones.
- Impacted Stone in the Neck: A stone that lodges in the infundibulum or neck of the gallbladder, often associated with an increased risk of cholecystitis.

Ultrasound Findings in Acute Cholecystitis

Cholecystitis is the acute inflammation of the gallbladder, usually caused by obstruction of the cystic duct by a gallstone ( calculous cholecystitis , >90% of cases). The major ultrasound criteria are:

1. Main Criteria (Greatest Sensitivity):

Impacted Stone in the Neck or Cystic Duct: Visualization of a stone lodged in the outlet of the gallbladder.
Positive Ultrasound Murphy's Sign: This is a dynamic clinical-ultrasound finding . It is considered positive when the patient's maximum pain is exactly reproduced by pressing the transducer over the gallbladder, and that pain ceases when pressure is applied to another area . It is highly specific.
Gallbladder Wall Thickening (>3-4 mm): The gallbladder wall, which is normally thin and regular (<3 mm), thickens homogeneously or in a "double layer" ( intramural edema ).

2. Secondary Criteria (Support the Diagnosis):

Perivesicular Fluid : Accumulation of fluid ( anezioic ) around the gallbladder, indicating inflammation and local peritoneal irritation.
Gallbladder Distension ( Hydrops ): Enlarged gallbladder (transverse diameter >4-5 cm), rounded and tense, filled with bile or sludge.
Thickening of the Wall in "Double Layer" or Intramural Streaks : Due to submucosal edema.
Gallbladder with "Corkscrew" Wall or Intramural Gas : In severe cases of emphysematous cholecystitis (infection by gas-producing bacteria), rare but serious.

Differential Diagnosis and Detectable Complications

Ultrasound helps to distinguish cholecystitis from other similar pains:

Simple Biliary Colic: Mobile stones WITHOUT signs of inflammation (wall thickening, positive Murphy, perivesicular fluid ).
Choledocholithiasis : Stones in the main bile duct, which can also be seen on ultrasound as hyperechoic structures with shadowing in the dilated duct.
Acute Hepatitis.
Acute Pancreatitis: Ultrasound also evaluates the pancreas.

Complications that ultrasound can detect:

Porcelain Gallbladder: Highly calcified gallbladder wall ( hyperechoic with complete posterior acoustic shadowing), associated with a higher risk of cancer.
Gallbladder in "Blackbird" ( Porcelain) Gallbladder ): Large single calculation that occupies all the light.
Perivesicular Abscess or Vesicular Empyema: Collection of pus.

Exploration Protocol and Limitations

The exam is systematic:

The gallbladder is visualized in longitudinal and transverse sections .
contents are evaluated (calculi, mud).
The thickness of the wall is measured .
Perivesicular fluid is being sought .
sonographic Murphy maneuver is performed .
The biliary tract is explored to rule out dilation or choledocholithiasis .

Main limitation: Ultrasound is less sensitive for detecting stones in the distal common bile duct (part of the biliary tract near the pancreas), where duodenal gas interferes. If there is a high clinical suspicion of choledocholithiasis , it is usually supplemented with MRCP or endoscopic ultrasound .

Conclusion: Image-Based Surgical Decision

Abdominal ultrasound is the cornerstone of diagnosis in acute biliary disease. It provides the surgeon with an immediate and highly reliable answer that guides decision-making. The identification of gallstones, along with signs of acute inflammation (positive Murphy's sign, wall thickening), is usually sufficient to indicate an emergency cholecystectomy . It is a tool that combines diagnostic accuracy with patient safety, optimizing treatment times and clinical outcomes.