This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Hepatic Tumors, Cysts, and Abscesses, Subject name: Surgery
A middle aged patients present with the complained of right hypochondrial pain. On X-ray, elevated right hemidiaphragm was seen. All of the following are the possible diagnoses except? 
Select and explain. 
A. Subphrenic abscess, B. Acute cholecystitis, C. Pyogenic liver abscess, D. Amoebic liver abscess in right lobe
B: Acute cholecystitis
Answer: B: Acute cholecystitis 
Explanation: Ans. b. Acute cholecystitis (Ref: Sabiston 19/e p1440-1447, 1487-1488; Schwartz 9/e p1115 -1116; style="font-size: 1.04761904761905em; font-family: Times New Roman, Times, serif">)Causes of Elevated HemidiaphragmAbove the diaphragmDiaphragmBelow the DiaphragmDecreased lung volume:* Atelectasis/collapse* Lobectomy/pneumonectomy* Pulmonary hypoplasia* Phrenic nerve palsy* Diaphragmatic eventration* Contralateral CVA: usually MCA distribution* Abdominal tumour* Subphrenic abscess* Liver abscess (Amebic and pyogenic)Radiological findings of Acute CholecystitisUSG findings: Presence of gallstones, thickening of the GB wall (>4 mm), pericholecystic fluid, GB distention, impacted stone, and a sonographic Murphy's signQ (focal tenderness directly over the GB).USG: IOC for diagnosing acute cholecystitisQ (sensitivity 85%, specificity 95%).HIDA scan: Gold standardQ for diagnosing acute cholecystitisHIDA scan: No filling of GB with the radiotracer (99mTc-HIDA) after 4 hours indicates an obstructed cystic ductQA normal HIDA scan excludes acute cholecystitisQ.