Quick Fire Cases
Shawn Shaji, MD
Cardiac Advanced Imaging Fellow
University of Utah/Primary Children's Hospital
Shawn Shaji, MD
Cardiac Advanced Imaging Fellow
University of Utah/Primary Children's Hospital
Evets Wood, RT
MRI technologist
Primary Children's Hospital
Mckenzie Foreman, RT
MRI technologist
Primary Children's Hospital
Barbara K. Han, MD
Professor
University of Utah
Edem Binka, MD
Assistant Professor
University of Utah
Spencer B. Barfuss, MD
Assistant Professor of Pediatrics
Boston Children's Hospital
Sanja Dzelebdzic, MD
Pediatric Cardiologist
University of Utah/Primary Children's Hospital
A 5-year-old female with DiGeorge syndrome, interrupted aortic arch with aberrant RPA from the ascending aorta, large muscular VSD with inlet extension, and ASD status post Yasui and PA unifocalization presented for routine CMR. Recent echocardiogram demonstrated dilated right ventricle with free conduit insufficiency, poorly visualized branch PAs, unobstructed left ventricular outflow tract, mild aortic insufficiency, and normal biventricular systolic contractility. In view of the patient’s complex anatomy and repair, ferumoxytol was ordered for contrast-enhanced imaging. Per our institutional protocol, an informed consent was obtained from the parent and 2 mg/kg of ferumoxytol was ordered to be compounded to a concentration of 2 mg/mL and infused over 15 minutes. Contrast was received from pharmacy and administered and per protocol with vital sign monitoring.
Diagnostic Techniques and Their Most Important Findings:
CMR was done on a 1.5T Siemens Magnetom Sola (Siemens Healthcare, Erlangen, Germany). The patient was sedated and intubated for the scan. Localizer images were obtained as ferumoxytol was being infused (Figure 1). There was subtle signal loss noted as the images were being obtained. T2W HASTE was performed in the axial, coronal, and sagittal planes with good quality imaging (Figure 2). Standard functional assessment was done with balanced SSFP cines (Figure 3). These sequences showed complete signal loss of the blood pool in contrast to the expected blood pool enhancement. Troubleshooting maneuvers were employed including assessing the coils, restarting the scanner, and performing a test scan on a staff member which revealed normal scanner function. A repeat attempt was made to scan the patient, but images continued to show complete signal loss. With consideration of ferumoxytol’s intrinsic properties, an overdose was strongly considered. Further investigation showed that ferumoxytol was compounded incorrectly and the patient received 30 mg/kg of ferumoxytol. The scan was terminated at this point and following consultation with toxicology and hematology, the patient was admitted to the pediatric intensive care unit for iron chelation therapy.
Learning Points from this Case:
The images showed signal loss in bright blood imaging localizers and SSFP cine images as ferumoxytol was being infused (Figure 1). Theoretically, due to its strong susceptibility effect, high ferumoxytol dose can result in signal loss (Bashir et al, Emerging use of Ferumoxytol 2015). In addition, signal loss may be related to microscopic field inhomogeneities with T2*-shortening effects that dominate with high doses of ferumoxytol. These effects were nulled by the spin echo sequence with the 180° refocusing pulse (Figure 2). With the increased use of ferumoxytol in pediatric and congenital CMR, it is important to inform the community of imaging findings consistent with a contrast overdose.
