- Oral presentation
- Open Access
Whole heart free breathing phase sensitive inversion recovery MRI integrated with iterative self navigation for 100% scan efficiency; a first patient study
© Ginami et al. 2016
- Published: 27 January 2016
- Late Gadolinium Enhancement
- Respiratory Motion
- Myocardial Scar
- Visual Grade
- Visible Scar
Phase Sensitive Inversion Recovery (PSIR)  allows for the visualization of myocardial scars using late gadolinium enhancement (LGE), ensuring robustness with respect to sequence timing. 3D whole-heart PSIR has been integrated with diaphragmatic navigator-gating (NAV)  to compensate for respiratory motion. However, both NAV and the need for two different datasets to be acquired (IR and reference) lead to a prohibitively long scanning time. Thus, integrating 1D respiratory Self-Navigation (SN)  with 3D-PSIR to obtain 100% scan efficiency is desirable. Unfortunately, signal and contrast variations between the IR and the reference dataset pose a major challenge. Here, we hypothesized that a recently introduced contrast independent iterative approach to 1D SN (IT-SN)  effectively suppresses respiratory motion in 3D-PSIR acquisitions.
Data acquisition was first performed in a cohort of 8 patients to ascertain the successful integration of IT-SN with 3D whole-heart PSIR, after a regular 2D PSIR LGE examination. In a second cohort (7 patients), data were acquired using a similar protocol after slow infusion (0.2 mmol/kg, Gadobutrol) yet without preceding 2D PSIR LGE. In both cases, a prototype 3D radial SN bSSFP  was used on a 1.5T MRI scanner (Magnetom Aera, Siemens). Imaging parameters were: TR/TE 2.9/1.45 ms, FOV 220 mm3, resolution 1.4 mm3, RF excitation angle 115°(IR) and 8°(reference), Bandwidth 140 Hz/Px, fat saturation, TI 250-320 ms. IT-SN was used for respiratory motion correction. For the first cohort, uncorrected PSIR datasets were compared with PSIR datasets corrected with IT-SN, by computing endocardial border sharpness (EBS), sharpness of visible scars (%SS) , and by visual grading provided by two experts (grades ranging from 4, fully diagnostic, to 0, non-diagnostic). For the second cohort, IT-SN corrected PSIR images were compared with IT-SN corrected IR images to evaluate the efficacy of myocardial signal suppression. SNR of blood and myocardium were computed together with CNR between blood and myocardium.
IT-SN allows for free-breathing motion suppressed 3D whole-heart PSIR imaging with 100% scan efficiency. When compared to IT-SN IR, myocardial signal is more effectively suppressed, providing an improved delineation of scar tissue. Studies in a larger patient cohort are now warranted.
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