Author:  Ashley Davidoff MD

copyright 2006

CLINICAL BACKGROUND- 

The clinical setting is usually in an elderly  patient who presents with findings consistent with acute pancreatitis, but without an associated history of alcohol abuse.

IMAGING STRATEGIES

WHAT STUDY?

In this situation the study of choice is an ultrasound of the right upper quadrant.  The purpose of the study would be to look for gall stones in the gallbladder and establish  the diagnosis of gall stone pancreatitis. A full abdominal ultrasound is not necessary since an examination of the pancreas at this stage is usually not helpful.  A plain film of the abdomen is not be necessary, unless the diagnosis is in question and the clinical diagnosis is broader ie “acute abdomen” .

Following recovery surgical treatment of the gall stones would be necessary.

A CT scan would not be necessary if the clinical diagnosis is well established and the patient is stable and shows recovery.  If the patient demonstrates instability or advancing disease, a CT of the abdomen is recommended  using a “pancreas protocol” implying a combination of a non contrast CT of the abdomen with a contrast enhanced CT of the abdomen and pelvis.  It is important to examine the pelvis for free fluid.

WHY? 

Based on the clinical presentation, the leading diagnosis is acute gallstone pancreatitis.  An focused ultrasound study (US) of the RUQ would serve best to define the presence of expected cholelithiasis.

The use of CTscan in the early stages of pancreatitis is debatable.  If the diagnosis is unequivocal then it is prudent to reserve CTscanning for the cases that do not resolve with conservative measures.  Hyperamylasemia is not specific and its absence does not preclude the diagnosis. There is a broad category of diseases that can cause hyperamylasemia. (eMedicine).  When the case presents with clinical severity based on Ranson’s criteria (eTools) CT scanning is definitely indicated to assess the baseline morphological extent.  Calcified stones may be seen on CT, in which case an US can be avoided.  On the other if stones are not seen, an US should be performed to confirm cholelithiasis since if present, elective cholecystectomy should follow.

BACKGROUND TO THE DISEASE:

Pancreatitis can be a life threatening disease and early diagnosis and assessment of the severity is key to early intervention.  Most common causes of the disease are alcoholic binges and gall stones.  Early leakage of fluid beyond the confines of the pancreas , even in the mildest of cases results in thickening of the retroperitoneal tissues, easily visible in most patients, and most often affecting the left sided Gerota’s fascia.

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WHEN?   

When the clinical diagnosis of acute gallstone pancreatitis is obvious then the US should still be performed to ensure the diagnosis.  In the absence of stones and  a severe case of pancreatitis, there are two approaches.  A  CT scan could be performed in the first few days of presentation with the intent of esatblishing baseline condition. On the other hand one could wait until the severity of the disease declares itself clinically and then image the person when recovery is not forthcoming and progression ensues.

HOW TO ORDER?

Ordering the US  should take place on the day of the patient’s admission, perhaps while still in the ER. In our institution a computerised form is generated which should state the study requested ie right upper quadrant ultrasound patients symptoms, ie “abdominal pain”,

a provisional diagnosis ie “suspect gallstone pancreatitis” and a specific intent ie “evaluate for gallstones”

If the diagnosis of pancreatitis is confidently established then a limited study of the RUQ .  If the diagnosis of pancreatitis is not clearly etablished then the study to be ordered is called an abdominal ultrasound which will include the liver, gallbladder, bile duct, pancreas and spleen.

PATIENT PREPARATION

The patient needs to be NPO for 4 hours and the study usually takes between 30-45 minutes .

CLINICAL RED FLAGS:

Fever or elevated WCC, blood pressure instability are important clinical facets.  If any of these is present, a CT scan is imperative to evaluate for an intrabdominal perforation or abscess..

Web References

American College of Radiology

    Acute Abdominal Pain and Fever

Acute Pancreatitis

Suspected Abdominal Abscess (

American Society of Gastroenterology

E Medicine eMedicine

For assistance with imaging strategies email  radiologist@thecommonvein.net