Contrast-Enhanced CT Protocol for the Fontan Pathway: Comparison Between 1- and 3-Minute Scan Delays.

Area of Science:

• Radiology
• Medical Imaging
• Cardiovascular Imaging

Background:

• Optimal contrast enhancement of the Fontan pathway is critical for accurate computed tomography (CT) evaluation.
• Current contrast-enhanced CT (CECT) protocols exhibit inconsistencies in scan delays and injection methods, impacting diagnostic quality.

Purpose of the Study:

• To compare objective measures of contrast enhancement between 1-minute and 3-minute scan delays for Fontan pathway evaluation.
• To determine the optimal contrast-enhanced CT protocol for assessing the Fontan pathway.

Main Methods:

• Retrospective, single-center study involving 41 patients with a 1-min delay and 36 patients with a 3-min delay.
• Utilized a biphasic injection protocol with 50% diluted contrast agent (2.0 mL/kg) and saline flush.
• Quantitatively evaluated cardiovascular enhancement, image noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR).

Main Results:

• The 1-min delay protocol demonstrated significantly higher mean cardiovascular structure densities (p < 0.001).
• Heterogeneous enhancement in the Fontan pathway was more frequent with the 1-min delay (p < 0.001).
• The 3-min delay protocol showed lower SNR and CNR (p < 0.001) despite more homogeneous enhancement.

Conclusions:

• A 1-minute scan delay in CECT offers superior contrast enhancement and diagnostic metrics (SNR, CNR) for Fontan pathway evaluation compared to a 3-minute delay.
• While a 3-minute delay improves homogeneity, it compromises overall enhancement quality, indicating a need for protocol refinement.