MR Angiography as the Preferred Test for Pulmonary Embolism During the Iodinated Contrast Media Shortage of 2022: A Single-Center Experience.

Closure of a GE Healthcare Shanghai facility in 2022 disrupted iodinated contrast media supply. Technologic advances have addressed limitations in use of pulmonary MR angiography (MRA) for pulmonary embolus (PE) diagnosis. To describe a single institution's experience in use of pulmonary MRA as an alternative to CTA for PE diagnosis in the general population during the 2022 iodinated contrast media shortage. This retrospective single-center study included all CTA and MRA examinations performed to exclude PE, from April 1 through July 31 (18 weekly periods) in 2019 (before the COVID-19 pandemic and contrast media shortage), 2021 (during the pandemic, but before the shortage) and 2022 (during both the pandemic and the shortage). From early May through mid-July of 2022, MRA served as the preferred test for PE diagnosis, to preserve iodinated contrast media. CTA and MRA reports were reviewed. Total iodinated contrast media savings by preferred use of MRA was estimated. The study included 4491 examinations in 4006 patients (mean age, 57±18 years; 1715 men, 2291 women): 1245 examinations (1111 CTA, 134 MRA) in 2019; 1547 examinations (1403 CTA, 144 MRA) in 2021; 1699 examinations (1282 CTA; 417 MRA) in 2022. In 2022, the number of MRA examinations was 4 (9, normalized to a seven-day period) in week 1, increased to maximum of 63 in week 10, and decreased to 10 in week 18. During weeks 8-11, more MRA examinations (range, 45-63) than CTA (range, 27-46) were performed. In 2022, seven patients with negative MRA underwent subsequent CTA within 2 weeks; CTA was negative in all cases. In 2022, 13.9% of CTA examinations, versus 10.3% of MRA examinations, were reported as having limited image quality. Estimated 4-month savings by preferred MRA use in 2022, assuming uniform linear growth in CTA utilization annually and 1 mL/kg CTA dose, was 27 liters of iohexol 350 mg/mL. Preferred use of pulmonary MRA for PE diagnosis in the general population helped to conserve iodinated contrast media during the 2022 shortage. This single-center experience demonstrates use of pulmonary MRA as a practical substitute for pulmonary CTA in emergency settings.