Leading Australian experts have provided practical advice on how to cope with the likely ongoing shortages of iodinated contrast agents for CT. They say it's essential to quantify contrast requirements, develop coherent strategies to rationalize its use, and review imaging protocols and practices.
It's important to target frequently ordered contrast-enhanced CT scans, improve triage to contrast-enhanced CT scans by ensuring consultant or specialist registrar referrals, implement risk-stratification algorithms, and use noncontrast CT whenever possible, according to Dr. Shalini Amukotuwa, first author of the article posted by the Journal of Medical Imaging and Radiation Oncology (JMIRO) on 30 May.
Dr. Shalini Amukotuwa from Monash Health."The most important thing is to identify the 'frequent flyers,' i.e., the main users of iodinated contrast media in CT," she told AuntMinnieEurope.com in an email on 5 June. "It's also important to think hard about whether we should really defer any oncology contrast-enhanced CT exams. We saw during the first waves of COVID-19 that deferring these scans led to delayed diagnosis and missed opportunity for treatment, with sometimes devastating consequences for patients and their families."
Amukotuwa is head of neuroradiology and director of MRI at Monash Health Imaging in Clayton, Victoria, which is the largest academic radiology department in Australia. She became very interested in the current shortage because of its impact on acute stroke imaging and because MRI is the alternative test for so many contrast-enhanced CT indications.
"Unlike in Europe, we use CT instead of MRI for "code strokes" because CT is easier to access in the emergency setting, which is important to achieve short door-to-needle and door-to-groin puncture times," she explained. "There's a real fear of delaying treatment by using MRI instead of CT, but in Europe you have clearly shown that MRI can be used efficiently for diagnosing and triaging patients with large vessel occlusion strokes. It simply requires a clear and well-practiced workflow."
She thinks radiology must use this crisis as an opportunity to review protocols and practices. MRI is the best test for first-line stroke imaging, and she's keen to see wider access to MRI. "We should take a leaf out of the book of Europe on this," said Amukotuwa, who also has a strong interest in using data to inform our healthcare services to deliver better patient care.
In this field, her JMIRO co-author Prof. Roland Bammer has conducted important studies published in the American Journal of Neuroradiology, evaluating changes to acute stroke imaging that can help navigate the contrast shortage, including five-minute stroke MRI protocol proposals as well as CT perfusion and angiography protocols with substantially reduced contrast volumes.
Use of other modalities
Alternative modalities, in particular nuclear medicine and MRI, should be considered if access allows it and diagnostic sensitivity isn't compromised, according to Amukotuwa. Hospitals must plan for the worst-case scenario of a lengthy scarcity of contrast media, create capacity in alternative modalities, and ensure adequate supplies of MRI contrast and nuclear medicine tracers to address increased demand, she said.
From a care provider's perspective, it would be positive to receive more frequent updates from the manufacturer about how it intends to get supply levels back to normal for customers. This would enable radiologists to better plan how long this transient shortage may last, including diverting resources to alternative modalities such as MRI, she noted.
"Statements from the vendor have been sparse, and other than the recent announcement that GE will return to full production capacity in the week of 6 June, we -- in the trenches -- haven't heard much. We can't tell how soon after GE commences full production, our stock levels will be back to normal," Amukotuwa continued.
In Australia, there has been considerable support from the Department of Health, which has tried to coordinate iodinated contrast medium (ICM) supplies and stock levels for all public hospitals, she pointed out. "Our stock level hasn't been depleted. This is mainly due to two factors: first, we received a few smaller shipments, and second the interventions we described in the [JMIRO] paper took hold."
"We did receive some stock from GE last week, and more is expected to arrive on 13 June. We have been advised to operate at 70%-80% of our normal operational consumption in June, to ensure that we have enough supplies. This will be reviewed based on supply forecasts for July when that information becomes available," she said.
Along with colleagues from Monash University, Clayton, Victoria, and St Vincent's Hospital, Fitzroy, Victoria, Amukotuwa has analyzed the effects of these strategies on contrast utilization in the first 14 days after implementation. They found they achieved a large reduction in contrast usage without needing to defer any outpatient contrast-enhanced CTs other than elective CT coronary and lower limb angiograms.
The group also studied the impact on alternative modalities -- e.g., ultrasound, MRI, and ventilation-perfusion (VQ) scans. This follow-up paper is currently under review.
Unanswered questions
Amukotuwa thinks the main questions to address are:
- What is the impact on patient care of the strategies that we have implemented? Did we miss any diagnoses? Did we miss any opportunities for treatment?
- Should the changes we made remain? If, for example, we can demonstrate that reducing contrast volumes for each study is not impairing diagnostic quality, it would make sense to stay with this approach. While using MRI for stroke as an alternative would probably be an easy answer -- provided the logistics can be sorted out -- for other primary clinical questions, the decision might not be so simple or contrast-enhanced CT remains the better test. "Keep in mind that CT is just a modality with an incredible throughput: We can probably scan three patients in CT for every patient in MRI," she said.
- Should countries and healthcare services rely on just one major supplier?
"I think countries are also seriously looking into diversifying the sources and producing their own ICM since this is so critical for healthcare. I think all of us had a significant 'blindspot' when it comes to contrast. While radiologists understand the importance of contrast, we are not focused on ordering and inventory management," she noted.
This experience shows that logistical and inventory management practices (in particular just-in-time ordering) and pursuit of competitive pricing create global dependencies and vulnerability of an entire sector to supply chain disruptions. "A lot of hospital procurement divisions and radiology leadership teams will, in the future, look at the whole supply chain from a different vantage point. I don't think any of us thought we would ever run out of ICM, so it's been an eye opener for many of us," Amukotuwa commented.
Overall, she thinks radiology can only address question two above by answering question one. "Question 1 is challenging to answer in the acute phase since the effects may be delayed and patients may not present until later. Currently, we are auditing reduced ICM dose "code stroke" CTs and nonenhanced CT abdominal scans to see if we are missing any strokes and abdominal emergencies, based on patients' follow-up clinical and imaging data, where available.
"We are also planning studies with our emergency department colleagues to assess the impact of more judicious use of [contrast-enhanced CT] on diagnosis, to see if we have patients presenting with late diagnosis and complications in the coming months," she noted.
