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Johns Hopkins Medical Imaging

Order Wisely: Selecting the Optimal Abdominal CT Protocol

Quick question: How is abdominal CT performed with & without IV contrast?

  1. (+) IV but no PO contrast
  2. (+) PO but no IV contrast
  3. scan pre & post IV
  4. scan pre & post PO

Answer:

C. Abdomen CT with & without contrast involves a non-contrast scan (no IV, no PO) and 1 or more scans following IV contrast infusion. This protocol delivers 2-4 times more radiation to the patient compared to abdomen CT with IV contrast and is more expensive for patients and payers.

The most widely used protocol for abdominal imaging is CT with IV contrast. Why is IV contrast important? Because the contrast enhancement of vessels & organs enables radiologists to make many diagnoses that are not apparent on a noncontrast scan.

When does CT with & without IV contrast add value for abdominal imaging? This protocol should only be used for the following indications:

  • Renal lesion characterization – mass vs cyst
  • Hematuria work up – to evaluate kidney, collecting systems and bladder for cancer
  • Indeterminate adrenal nodule characterization – adenoma vs metastasis
  • Follow-up after endovascular aortic stent repair – to evaluate for endoleak
  • Gastrointestinal hemorrhage – to identify bleeding in the bowel
  • Characterizing a focal liver mass – benign vs malignant

Otherwise, if patients don't have contraindications to IV contrast, order CT abdomen +/- pelvis with IV contrast. Radiologists generally need the pelvis to fully characterize abdominal pathology. Exceptions include:

  • Adrenal nodule characterization
  • Pancreatic cyst follow-up
  • Renal mass vs cyst with prior imaging

The best resource for questions about imaging test or protocol is your radiologist. Reach out and a Johns Hopkins radiologist will help you pick the best exam and the correct protocol. Johns Hopkins providers can now reach out via Epic on the sign-in page under “Radiologist Services” with step-by-step instructions.

Abdomen CT: Protocol Selection

CT with IV contrast

CT with & without IV

CT without IV

  • Most widely use protocol
  • <10% of orders
  • 2-4x radiation dose for patient
  • Contraindication to IV contrast
  • Select indications

Clinical indications

  • Solid and hollow visceral organ pathology
  • Peritoneal and retroperitoneal disease
  • Majority of oncology diagnosis and surveillance

Clinical indications

  • Adrenal nodule work up (indeterminate lesion <4 cm)
  • Renal mass vs cyst
  • Hematuria work up
  • s/p Aortoiliac stent repair
  • GI bleeding

Clinical indications

  • Renal colic/stone
  • Neutropenic fever
  • Dropping Hgb
    • Prefer IV contrast

This work is intended for use to assist hospital and healthcare audiences; however, Johns Hopkins makes no representations or warranties concerning the content or clinical efficacy of this work, its accuracy or completeness. Johns Hopkins is not responsible for any errors or omissions or for any bias, liability or damage resulting from the use of this work. This work is not intended to be a substitute for professional judgment, advice or individual root cause analysis.