A plant in Shanghai that produces approximately 80% of the world’s IV contrast was shut down due to COVID lockdowns in the area.
The plant has already begun to reopen but ACEP anticipates an ongoing shortage until the supply fully recovers.
In a message from Gillian Schmitz, ACEP President, it is estimated that the contrast shortage will go well into June and possibly July 2022.(1)
ACEP created smart phrases that can be edited and used under these circumstances.
The American College of Radiology published a statement updated on May 13, 2022.(2)
Use alternative studies, ie ultrasound, MRI, nuclear medicine.
See their full statement for other department and hospital wide recommendations.
Aortic dissection(3)
CT angiogram is the gold standard, and you may need to save any available contrast when suspicious for an aortic dissection.
Ultrasound
Ultrasound should not be relied upon to make the diagnosis, but if there are positive findings can expedite surgical consult or transfer (ACEP Clinical Guidelines).(4)
Transesophageal echocardiogram (TEE)
Sensitivity is 86-100%
Significant limitations: requires sedation, special equipment and team
Not a practical modality in most emergency departments.
MRA aorta
95-100% sensitivity, also high 90’s for specificity
Limitations: takes longer, may not be available, requires a stable patient.
Abdominal aortic aneurysm (AAA)(5)
Ultrasound
Highly sensitive and can be done bedside
Limitations: The lack of free fluid on ultrasound cannot rule out rupture of an abdominal aortic aneurysm.
CT
According to the CorePendium chapter: “Contrast is not necessary to identify the presence of the aneurysm, but the addition of contrast increases the sensitivity for diagnosing a rupture and allows more accurate sizing and distinction of the patent lumen from mural thrombus.”
CT is better at seeing retroperitoneal bleeds than ultrasound.
Consider a noncontrast CT if suspicious for AAA
Rupture is likely in a patient who is hypotensive with abdominal pain and AAA on noncontrast CT.
Pulmonary embolism(6)
CT pulmonary angiogram (CTPA)
CTPA is the gold standard for this diagnosis.
Consider no imaging if your clinical suspicion is low.
Use gestalt and/or clinical decision tools to assess the need for imaging.
Become familiar with the YEARS score that allows for higher cutoff points for d-dimer in some cases.(7)
Ventilation-perfusion (V/Q) scan
Listed by the American College of Radiology in the same category as CTPA in their Appropriateness Criteria (“Usually appropriate”).(8)
Sensitivity 85%, specificity 93%
This is close to CT PA
Limitations: normal chest x-ray, nuclear medicine technician availability, takes longer, needs a cooperative patient for breath holding and positioning.
Ultrasound
Ultrasound can evaluate for signs of right heart strain but cannot make the definitive diagnosis.
Lower extremity doppler
Consider lower extremity doppler, especially if there are clinical signs or symptoms of DVT.
Initiating anticoagulation will treat both DVT and PE.
Appendicitis
Non-contrast CT is adequate.
A meta-analysis published in the Annals of Emergency Medicine in 2010 evaluated the diagnostic accuracy of noncontrast CT for appendicitis.(9)
93% sensitivity, 96% specificity
This was determined to be adequate.
No benefit to adding oral or rectal contrast
This paper was discussed on EMA previously.(10)
Diverticulitis(11)
Non-contrast CT
Specific data addressing sensitivity and specificity of non-contrast CT for diverticulitis was not found on brief literature review.
There is a retrospective study on noncontrast CT for renal calculi and looked at alternative diagnoses.(12)
Diverticulitis was identified as an alternate diagnosis in 1-2% of these patients.
Findings on noncontrast CT included colonic wall thickening and haziness of the pericolonic fat.
Abdominal ultrasound
Abdominal ultrasound has been shown to have a sensitivity above 90% for diverticulitis.
Limitations: operator dependent and unless asked to do this frequently, the sensitivity is likely much lower.
Generalized abdominal pain in older adults
Geriatric patients with abdominal pain have a very high chance of being positive
In a retrospective review of over 400 adults ≥80 years of age, 55% of them had a positive CT scan with actionable findings.(13)
Positive findings included: bowel obstructions, diverticulitis, bowel ischemia, appendicitis, and vascular emergencies (dissection, AAA, arterial or venous thrombosis).
Non-contrast CT
Consider starting with a non-contrast CT
Try to reserve contrast for vascular emergencies
Ultrasound
History and physical exam may help narrow the differential diagnosis such that an ultrasound is an appropriate study.
Trauma
Work with your trauma surgeons (locally or at the receiving hospital) to discuss on a case by case basis.
Consider non-contrast CT in stable patients.
Strokes
Work with your interventional radiologists and neurologists.
For many patients, it may be appropriate to obtain non-contrast head CT followed by MRA head and neck (or carotid ultrasound) as an inpatient.
Summary
Try to limit IV contrast to vascular studies.
Think of other imaging modalities that may be able to answer the question and lean on your assessment to guide focused imaging.
Discuss within your department how to ration contrast.
Work with other departments so there is a common goal.
Call your radiologist and discuss cases when uncertain.
There is no simple answer here but perhaps a silver lining. Perhaps we will become more judicious with CT scans and reduce radiation exposure, expense, and throughput. Hopefully this will not come at the expense of harm to patients.
