Why the study?
Visualizing aortic valve dynamics is important for diagnosing valvular diseases, but MRI has been limited by temporal resolution.
Does get-SPEEDI MRI provide more accurate measurements of aortic valve dynamics compared to conventional bSSFP MRI in healthy subjects?
Observational (n=12)
Does get-SPEEDI MRI provide more accurate measurements of aortic valve dynamics compared to conventional bSSFP MRI in healthy subjects?
The get-SPEEDI MRI technique with sub-millisecond temporal resolution provides more accurate visualization and measurement of aortic valve dynamics than conventional MRI, closely matching echocardiography.
Background Visualization of aortic valve dynamics is important in diagnosing valvular diseases but is challenging to perform with magnetic resonance imaging (MRI) due to the limited temporal resolution. Purpose To develop an MRI technique with sub‐millisecond temporal resolution and demonstrate its application in visualizing rapid aortic valve opening and closing in human subjects in comparison with echocardiography and conventional MRI techniques. Study Type Prospective. Population Twelve healthy subjects. Field Strength/Sequence 3 T; gradient‐echo‐train‐based sub‐millisecond periodic event encoded imaging (get‐SPEEDI) and balanced steady‐state free precession (bSSFP). Assessment Images were acquired using get‐SPEEDI with a temporal resolution of 0.6 msec. get‐SPEEDI was triggered by an electrocardiogram so that each echo in the gradient echo train corresponded to an image at a specific time point, providing a time‐resolved characterization of aortic valve dynamics. For comparison, bSSFP was also employed with 12 msec and 24 msec temporal resolutions, respectively. The durations of the aortic valve rapid opening ( T ro ), rapid closing ( T rc ), and the maximal aortic valve area (AVA) normalized to height were measured with all three temporal resolutions. M‐mode echocardiograms with a temporal resolution of 0.8 msec were obtained for further comparison. Statistical Test Parameters were compared between the three sequences, together with the echocardiography results, with a Mann–Whitney U test. Results Significantly shorter T ro (mean ± SD: 27.5 ± 6.7 msec) and T rc (43.8 ± 11.6 msec) and larger maximal AVA/height (2.01 ± 0.29 cm 2 /m) were measured with get‐SPEEDI compared to either bSSFP sequence ( T ro of 56.3 ± 18.8 and 63.8 ± 20.2 msec; T rc of 68.2 ± 16.6 and 72.8 ± 18.2 msec; maximal AVA/height of 1.63 ± 0.28 and 1.65 ± 0.32 cm 2 /m for 12 msec and 24 msec temporal resolutions, respectively, P < 0.05). In addition, the get‐SPEEDI results were more consistent with those measured using echocardiography, especially for T ro (29.0 ± 4.1 msec, P = 0.79) and T rc (41.6 ± 4.3 msec, P = 0.16). Data Conclusion get‐SPEEDI allows for visualization of human aortic valve dynamics and provided values closer to those measured using echocardiography than the bSSFP sequences.
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Zhong et al. (2021) conducted an observational in Healthy subjects (n=12). get-SPEEDI MRI vs. bSSFP MRI and M-mode echocardiography was evaluated on Durations of aortic valve rapid opening (Tro), rapid closing (Trc), and maximal aortic valve area (AVA) normalized to height (p=<0.05).
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