Oral Abstract Session
SCMR 22nd Annual Scientific Sessions
Congenital Heart Disease (CHD) can affect both arterial and venous systems. Bright-blood MRI is typically performed for anatomy assessment, with a reliance on Gadolinium (Gd)-based contrast agents to depict structures such as the pulmonary veins, collateral vessels, or regions of disturbed blood flow. Black-blood MRI may instead be preferable for the delineation of e.g. small vessels. However, sequential scans often entail prolonged and unpredictable examination times. Moreover, the use of Gd is not ideal in CHD, where repeated scans may be needed. We propose a novel free-breathing non contrast-enhanced (non-CE) sequence providing bright- and black-blood whole-heart images that allows for the visualisation of both arterial and venous structures in a single efficient examination.
Methods: The proposed 3D whole-heart bright- and black-blood (BOOST) sequence partially resembles that described in , but exploits magnetization transfer (MT) contrast for improved delineation of venous structures (Fig.1). The use of image-based navigation  and non-rigid respiratory motion correction  allows for shorter and predictable scan times. Data acquisition was performed in 10 patients with CHD (7 M, 28.4±13.1 years) on a 1.5T system (Siemens Magnetom Aera). Imaging parameters: resolution 1.4x1.4x2.8 mm (reconstructed to 1.4mm3), flip-angle 90deg, TE/TR 1.5/3.2ms, MT-preparation: 15 Gaussian pulses, flip-angle 800deg, frequency offset 3000Hz, duration 20.5ms. A non-CE 3D whole-heart clinical bright-blood sequence was acquired for comparison (T2-prepared, bSSFP, 1.5mm3, GRAPPA 2x, flip-angle 90deg). Signal to noise of arterial and venous blood (SNRart and SNRven) was computed for bright-blood BOOST, while contrast to noise was computed for both BOOST and clinical sequences (CNRart and CNRven). Diameters of the great vessels were assessed as per standardized reporting for both bright-blood sequences.
MTC-IR BOOST provided comparable high-quality depiction of arterial and venous blood (SNRart=21.6±9.5 and SNRven=19.9±8.3, P=NS, CNRart=12.7±3.2 and CNRven =10.9±2.5ms, P=NS, Fig.2). The clinical sequence provided high-quality depiction of arterial blood, with a significant detrimental effect on the depiction of the venous structures (CNRart=13.7±5.6 and CNRven=5.5±4.3, P<0.005, Fig.3). BOOST resulted in excellent delineation of the pulmonary veins and improved luminal signal in the context of altered flow (e.g pulmonary regurgitation/stenosis or coarctation) (Fig.3). Excellent agreement was observed between MTC-IR BOOST and standard clinical sequences for the measurement of great vessel diameters (Fig.3).
The MT-prepared BOOST sequence provides high-quality, non-contrast, bright- and black-blood visualization of cardiac anatomy including both arterial and venous structures that can obviate requirements for Gd usage in patients with CHD, making it an ideal candidate for screening and follow-up in this population.