Correlation Between Contrast Time-Density Time on Digital Subtraction Angiography and Flow: An in Vitro Study

Area of Science:

• Medical Imaging
• Biomedical Engineering
• Cardiovascular Research

Background:

• Digital subtraction angiography (DSA) excels at visualizing cerebral vasculature anatomy.
• Current DSA hemodynamic assessment is often subjective and lacks reliable quantitative flow values.
• Existing algorithms to semiquantify DSA flow data have limited validation against precise flow measurements.

Purpose of the Study:

• To develop and validate a novel method for semiquantifying cerebral blood flow using DSA data.
• To assess the correlation between a new Time-Density Index (TDI) and actual flow rates in a controlled model.
• To determine the potential of DSA-derived hemodynamic parameters for objective clinical evaluation.

Main Methods:

• An in vitro flow model with contrast material injection was used.
• DSA images were acquired in multiple projections (anterior-posterior, lateral, oblique).
• Custom MATLAB code analyzed image intensity changes to derive time-density plots and calculate TDI based on cross-sectional area and time-density components.

Main Results:

• All tested TDI components (TDI10%-100%, TDI100%-10%, TDI25%-25%) demonstrated significant correlation with flow rates (P < 0.001).
• High correlation coefficients (r=0.91-0.97) were observed in anterior-posterior DSA projections.
• Significant correlations were also found in lateral and oblique DSA projections, though TDI100%-10% showed weaker correlation in the lateral view (r=0.57, P=0.03).

Conclusions:

• The developed Time-Density Index (TDI) derived from DSA shows a significant correlation with blood flow rates.
• This in vitro study suggests TDI offers a promising semiquantitative approach for evaluating cerebral blood flow.
• While acknowledging potential limitations of in vitro models, this method could enhance objective hemodynamic assessment in clinical practice.