Oral Contrast for Abdominal CT: Nay (Or Let s Make CT Great Again ) Mark E. Baker, MD, FACR, FSAR, FSCBT/MR Professor of Radiology Cleveland Clinic Lerner College of Medicine of CWRU Staff Radiologist, Abdominal Imaging, Imaging & Digestive Disease Institutes, Cleveland Clinic Sept 20, 2016 8:00-8:30 AM
CONFLICT OF INTEREST DISCLOSURE: BRACCO: Informal Consultations SIEMENS HEALTHCARE: Research Agreement Radiation Dose Assessment & Reduction in MDCT including Iterative Reconstruction (Salary Support, Hardware & Software) (Not Applicable to the Presentation)
CONFLICT OF INTEREST DISCLOSURE: BRACCO: Informal Consultations SIEMENS HEALTHCARE: Research Agreement Radiation Dose Assessment & Reduction in MDCT including Iterative Reconstruction (Salary Support, Hardware & Software) (Not Applicable to the Presentation)
Oral Contrast: Assumptions Positive Oral Contrast Media High Attenuation Adults Growing Evidence that in Some Instances Not Necessary in Adolescents Reasonable Exposure Settings Not Low-Dose, Quasi-mSv Studies Excludes CT Indications that Definitely Need Some Oral Contrast Agent
Oral Contrast: Assumptions When is It Definitely or Often Essential Post-Bowel Resection Patients Leak Possible Oral & Often Rectal CT Enterography Uni-Phasic in Crohn s Multi-Phasic in Obscure GI Gleeding? Thin or Cachectic Adults without Substantial Mesenteric Fat
Oral Contrast: Historical Rationale Initial Use in Late 70 s & Early 80 s to Opacify the Small Bowel 1 Eliminate Pseudo-Tumor Dx Distinguish Bowel from Mesenteric Pathology Often When Bowel Not Opacified, Either: Re-Scan Patient After Delay More Oral Administered & Patients Re- Scanned Glucagon Sometimes Administered CT Technology Incremental, 5-10 Sec Rotation 8-10 mm, Axial Reconstruction Slices with 320 x 320 Matrix Sometimes Discontinuous for Surveys (Lymphoma;Abscess) IV Contrast Bolus Followed by Drip
Oral Contrast: Is It Now Necessary? Modern Abdominal Scanners Sub-Sec Rotation Times, MDCT Volume Scanners Isotropic Imaging 2-5 mm Reconstructions, 512 x 512 Matrix Unlimited Reconstruction Planes Distinguishing Bowel from Mesenteric Mass Almost Never an Issue Intra-Luminal Pathology Uncommonly to Rarely Identified
Oral Contrast: Is It Now Necessary? Modern Abdominal Scanners We Don t Prep Patients to Eliminate Colonic Feces We Don t Routinely Administer Rectal/Colonic Contrast If We Do, We Uncommonly Reflux to Cecum for Complete Opacification of Colon & Rectum Why Do We Feel Compelled to Attempt to Opacify the Small Bowel
Oral Contrast: Routine A/P CT Patient Experience Oral Contrast Not Palatable Large Volume Consumed Inconsistently N/V Relatively Frequent in Sick Patients Patients Often Unable to Ingest 1000-1500 cc Contrast Time Consuming Is End Point Achieved? Bowel Inconsistently Opacified We Don t Rescan Patients After More Oral Contrast Media Any More
Oral Contrast When is It Definitely Not Needed N,V & SBO Likely Acute GI Bleed Elevated Lactate Ischemic Bowel CTA Acute Appendicitis & Acute Diverticulitis Blunt Abdominal Trauma F/U Oncology Patients
Oral Contrast in ED Time to Disposition May be the Only Metric Delay in Disposition & Dx Has Been Defined as a Quality Issue in ED s Delay in Disposition & Dx Can Affect Patient Outcome Problem Compounded by # Patients in ED Overcrowding is a Major Issue in ED Method of Recruiting Patients
ED Time is THE Metric Many Studies Ordered by PA s & CNP Protocol Driven Abdominal Pain Exam Often Ordered as a Survey Admit Watch Send Home
Oral Contrast in ED Not Necessary in Blunt Trauma Does Not Alter Dx Efficacy of MDCT in Acute Abdominal Pain Does Not Alter Dx Efficacy of MDCT in Acute Appendicitis or Diverticulitis Not Necessary in SBO or Ischemia Not Necessary in F/U Oncology Patients
Why Oral Contrast May Be Necessary Visceral/Mesenteric Fat vs Subcutaneous Fat Visceral/Mesenteric Fat is THE Inherent Contrast in the Abdomen Identifying Bowel Abnormalities May Be Confounded by Visceral Fat Absence. However, Studies on Effect of BMI without Oral Contrast are Equivocal Relationship Between BMI & Visceral Fat Not Direct
Why Oral Contrast is Not Necessary in Routine A/P CT Bowel Identified Easily & Routinely No Modern Studies that Show that Efficacy is Improved Preponderance of Evidence Suggests that Efficacy is not Altered if Oral Contrast Omitted Time Commitment/Discomfort/Distaste Should Not Be Minimized Patient Experience Becoming a Critical Factor in Satisfaction
Oral Contrast in Routine A/P CT: Conclusion It is Not Necessary We Use It Because: It s the Way We ve Always Done It We Worry We re Missing Something No Data That We Identify Pathology If We Use It Contrary Data Exists Showing It is Not Necessary As In All Medicine, As with Patient Exposure, Oral Contrast Should be Administered Rationally & Specifically on a per Patient Basis