Image-based Navigation with Ferumoxytol Improves Reliability of Whole Heart Acquisition in Children and Adults (RF_SA_485)

Cardiac magnetic resonance angiography (MRA), particularly coronary evaluation, can remain variable in quality using conventional respiratory navigation strategies due to irregular respiratory patterns even in sedated patients. Motion correction strategies have shown promise in improving efficiency and quality. We have previously reported excellent results with a non-contrast 3D whole-heart sequence with bright-blood (BB) and dark-blood (DB) phase sensitive inversion recovery (IR) using image-based navigation (iNAV) and a variable-density Cartesian spiral-like profile order trajectory (VD-CASPR).  However, resolution and contrast limitations still make resolving very small structures challenging.  This is especially notable in patients with anomalous coronary arteries with proximal narrowing, where resolving the proximal coronary is important for surgical planning.  To this end we modified the iNAV sequence for use with ferumoxytol utilizing gradient readouts with an IR preparation (iNAV-FLASH).  We hypothesized that iNAV-FLASH acquisitions improved reliability of the MRA, particularly in delineating coronary anomalies.

Methods:

Pts undergoing clinically indicated CMRs from July 2023 to August 2024 were prospectively enrolled and scanned at 1.5T (AVANTO FIT, Siemens) using an iNAV-FLASH research sequence employing an IR gradient echo sequence (IR-FLASH) acquired after ferumoxytol infusion.  A subset of patients had a conventional respiratory navigated IR-FLASH.   Both imaging methods were rated on a 1-4 scale: 1=non-diagnostic, 2= significant image degradation, 3=mild image degradation, and 4=sharp delineation of the anatomic structures including the coronaries.  Group comparisons used a paired t-test (two-tailed, p< 0.05).

Results:

151 pts, mean age 11.7 years (range=4 months- 63 years) underwent iNAV-FLASH imaging. 44 had an IR-FLASH for comparison.   28 pts had coronary anomalies (13 with right coronary either high or from the left sinus, 4 with left coronaries from the right sinus). Coronary anomalies were delineated on all iNAV-FLASH exams with a mean score=3.9, compared to a score of 2.9 for conventional IR-FLASH (p< 0.01).  Scores were not significantly different between sedated and non-sedated exams.

Conclusion:

In our series spanning a large age range from infants to adults, iNAV-FLASH imaging consistently outperformed conventional navigated IR-FLASH imaging and led to more reliable delineation of small structures including coronaries in both sedated and non-sedated populations.

Anomalous RCA from high above the left sinus imaged after ferumoxytol using iNAV with a gradient readout and non-selective inversion preparation.

Anomalous RCA from high above the left sinus, same pt imaged with conventional diaphragm navigation, degraded due to inconsistent respirations.