Content from Radiology Email June 20, 2011

Minimizing CT Radiation Dose: Ordering the Most Appropriate CT Scan


The diagnostic and clinical benefits of CT scans are well established for a wide array of clinical indications. In most clinical scenarios, a contrast enhanced scan is ideal - there is no indication for performing the scan both with and without contrast.  Many different strategies are used to minimize radiation dose. A critical strategy to ensure that the lowest possible radiation dose is used is to order a CT with Contrast or CT without Contrast (not both) whenever possible. As you may be aware, and has been recently publicized, radiation dose may be reduced 50% by ordering only WITH or WITHOUT contrast, but not both. In some cases, MRI may be an appropriate alternative as well. For further reference, please visit The American College of Radiology (ACR) Appropriateness Criteria Website ( This site has evidence-based guidelines to choose the most appropriate imaging test for a specific clinical condition.


In general, it is recommended that a CT scan be ordered WITH CONTRAST ONLY or WITHOUT CONTRAST ONLY for the indications listed below.


CT Scans recommended to be performed WITH CONTRAST ONLY Abdominal Aortic Aneurysm Abdominal Mass on physical exam Abdominal Pain Aortic Dissection follow-up Cancer follow-up Fever without source Inflammatory Bowel Disease CT Enterography Hemoptysis Lung Cancer Metastatic Disease Neck Mass or Adenopathy Pediatric Neck and Chest (unless contrast contraindicated) Prostate Cancer Staging and follow-up Suspect Abscess or Infection Suspect Aortic Dissection Suspect Appendicitis Suspect Diverticulitis Suspect Liver metastases Suspect Pancreatitis Suspect Pulmonary Embolism


Suspect Small Bowel Obstruction

Trauma to Chest or Abdomen

Virtual Colonoscopy Screening


CT Scans recommended to be performed WITHOUT CONTRAST Head for Headache or Trauma Renal Stones Sinuses for Sinusitis Suspect Renal Stones Spine Trauma or DJD


CT Scans which generally REQUIRE WITH AND WITHOUT CONTRAST Adrenal Mass - initial evaluation Bladder Carcinoma follow-up Hematuria evaluation in Adult (other than Stone Disease, which is without contrast) Jaundice evaluation Liver Mass - initial evaluation after Ultrasound Liver for Hepatocellular Carcinoma Pancreatic Neoplasm Evaluation Renal Mass - first evaluation Suspect Aortic Dissection - first evaluation