This case is an excellent example of a large population who are visiting the hospital with one of the gallstone-related diseases.  

Acute cholecystitis is one of the most common reasons for hospital admission with acute abdominal pain. Approximately 90–95% of acute cholecystitis is related to gallstones, with 5–10% of cases due to acalculous disease.

Calculous cholecystitis refers to infection and inflammation of the gallbladder wall caused by irritation from gallstones, and this can be an acute or chronic process.

The typical imaging features of acute cholecystitis are as follows: gallbladder wall thickening, pericholecystic fluid and a distended gallbladder.

As such, ultrasound is the imaging modality of choice for the initial assessment of suspected gallbladder pathology.

Magnetic resonance cholangiopancreatography (MRCP) is typically performed using heavily T2-weighted sequences which are particularly helpful in delineating ductal anatomy. Gallstones typically appear as low signal or signal void on T2-weighted imaging surrounded by T2 hyperintense bile. MRCP has largely replaced endoscopic retrograde cholangiopancreatography (ERCP) as the gold standard for diagnosing choledocholithiasis due to its high sensitivity of 90–94% and specificity of 95–99% without the use of ionizing radiation or ERCP-related complications such as pancreatitis which can result in significant morbidity and even mortality.