Triage acuity first
Peritonitis, haemodynamic instability, suspected ischaemic bowel, suspected ruptured aneurysm, and uncontrolled vomiting belong in an emergency department, not in an outpatient imaging queue. The framework below applies to ambulatory patients with localisable pain who are clinically stable.
Right upper quadrant
Abdominal ultrasound (RUQ) is the first study for suspected cholelithiasis, cholecystitis, or biliary obstruction. It evaluates the gallbladder, intra- and extra-hepatic ducts, and liver parenchyma without radiation. CT is reserved for cases where ultrasound is non-diagnostic, when complications are suspected, or when a broader differential is in play.
Suspected renal colic
Non-contrast CT of the abdomen and pelvis (renal stone protocol) is the highest-sensitivity study for ureteral and renal calculi and is the typical outpatient first-line. Ultrasound can be used to screen in young patients, in pregnancy, or when minimising radiation is the priority, accepting lower sensitivity for small distal stones.
Right or left lower quadrant
Suspected appendicitis has its own dedicated pathway — see the appendicitis guide for the ultrasound-first or CT-first decision based on patient population. Suspected diverticulitis, colitis, or non-specific left lower quadrant pain in adults is best evaluated with CT abdomen and pelvis with IV contrast.
Generalised or epigastric pain
When pain is poorly localised, when an inflammatory or neoplastic process is in the differential, or when prior workup has been non-diagnostic, CT abdomen and pelvis with IV contrast is the highest-yield single study. Add oral contrast at the radiologist's discretion based on the indication.
Pregnant patients
Whenever the clinical question can be answered with ultrasound — RUQ biliary disease, appendicitis in the first or second trimester, renal — that is the preferred first study in pregnancy. If CT becomes necessary, the decision should be made with the obstetrician and weighed against the risks of delayed diagnosis.
Ordering with Precise
Abdominal ultrasound and CT abdomen and pelvis (with or without IV contrast) are available across the network with body imaging sub-specialty reads. Renal stone protocol and standard with-contrast protocols are both supported.
Questions referring offices ask first.
Ultrasound or CT for RUQ pain?
Ultrasound first. CT is reserved for non-diagnostic ultrasound or when a broader differential is suspected.
Do I need oral contrast?
Not routinely. We will determine whether oral contrast adds value at the protocolling step based on the indication.
Can a pregnant patient have CT?
Yes, when the diagnostic need outweighs the risk and ultrasound is non-diagnostic. We coordinate dose with the indication and trimester.
Educational reference for referring providers. Not a substitute for clinical judgement or the current official appropriateness criteria. References imaging modalities offered by Precise; modalities not in our network are out of scope.