Use of a 3D respiratory navigated IR-FLASH sequence after gadofosveset in the pediatric and adult congenital population

While CMR has become instrumental in imaging complex congential heart disease (CHD), limitations remain including significant flow and metal artifact on cine images. 2D dark blood imaging generally requires gating to diastole which may not capture the maximal vessel dimensions, is time consuming and dependent on precise plane positioning. Traditional 3D whole heart sequences are also sensitive to flow and metal artifact. 3D respiratory navigated FLASH with an inversion recovery pulse (IR-FLASH) post-gadofosveset potentially overcomes all of these limitations. Furthermore, it is ideal for generating high resolution isotropic datasets of the blood pool for 3D modeling. We present our experience with IR-FLASH for imaging native and repaired CHD.

We retrospectively reviewed our experience with IR-FLASH after gadofosveset. Respiratory navigating was employed with typical settings including isotropic voxels of 1.0 to 1.3 mm, TE 1.6 msec, TI 260 msec, and flip angle of 18 degrees. The TI was lowered to as low as 140 for systolic gating. Late systolic or diastolic quiescence was chosen for cardiac gating. We compared the IR-FLASH sequence to dynamic MRA, cine, and SSFP whole heart imaging when available.

IR-FLASH after gadofosveset can be routinely implemented in a wide range of heart disease. It is less sensitive to flow and metal artifact than SSFP sequences. It can be reliably gated to both systole and diastole. Gating to systole allows for better definition of semilunar valve morphology, RVOT morphology, and maximal root dimensions. The high resolution, contrast, and ability to scan with isotropic voxels makes it ideal for generating 3D models for computational analysis or printing.

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