Abstract
Methods 18 patients age range 0-10 years (12/18 were </= 5 years), were imaged under intravenous sedation for the following CHD indications: aorta or aortic arch morphology (8/18), branch pulmonary arteries (7/18), systemic veins (4/18), pulmonary veins (3/18), and systemic arteries (1/18). Heart rates ranged from 76-160 (mean 102 bpm). A freebreathing trCEMRA sequence was used with the following acquisition parameters: TR 4-5.5 ms, TE 1.2-1.6 ms, flip angle 35-45°, CENTRA k-space filling, acquired voxel size 1-1.3 × 1.1.3 × 2-2.8 mm3, reconstructed voxel size 0.651 × 0.65-1 × 1-1.4 mm3, number of dynamics 9-17, keyhole percentage 25-38%, two-dimensional SENSE factor 2 × 1-2 × 2, gadolinium dose 0.2 mmol/kg, and injection rate 1-3 cc/second. The number of phase encoding steps was adjusted so that the dynamic scan time was synchronized with the duration of the respiratory cycle. Respiratory rates ranged from 16-32/min. Dynamic times for the 3D MRA ranged from 1.9 to 3.6 seconds.
Highlights
In children with CHD, achieving adequate separation of right-sided, left-sided, and venous structures using conventional CEMRA is hampered by high heart rates and the fast circulation
To investigate the feasibility of a free-breathing time resolved CEMRA acquisition that is suitable for children with high heart rates using a keyhole approach combined with parallel imaging
A freebreathing time resolved CEMRA (trCEMRA) sequence was used with the following acquisition parameters: TR 4-5.5 ms, TE 1.2-1.6 ms, flip angle 35-45°, CENTRA k-space filling, acquired voxel size 1-1.3 × 1.1.3 × 2-2.8 mm3, reconstructed voxel size 0.651 × 0.65-1 × 1-1.4 mm3, number of dynamics 9-17, keyhole percentage 25-38%, two-dimensional SENSE factor 2 × 1-2 × 2, gadolinium dose 0.2 mmol/kg, and injection rate 1-3 cc/second
Summary
In children with CHD, achieving adequate separation of right-sided, left-sided, and venous structures using conventional CEMRA is hampered by high heart rates and the fast circulation. The need for visualizing small structures prolongs the acquisition time, and necessitates intubation and breath-holding to reduce motion induced blurring. To investigate the feasibility of a free-breathing time resolved CEMRA (trCEMRA) acquisition that is suitable for children with high heart rates using a keyhole approach combined with parallel imaging
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