Flow measurements with digital subtraction densitometry in a steady flow experimental model

Area of Science:

• Medical Imaging
• Fluid Dynamics

Background:

• Accurate measurement of blood flow rates is crucial in various medical applications.
• Digital subtraction angiography (DSA) offers a non-invasive method for visualizing blood flow.

Purpose of the Study:

• To evaluate the accuracy of computerized densitometry for flow rate measurement in model experiments.
• To compare the performance of the Stewart-Hamilton dilution technique and direct bolus velocity measurements.

Main Methods:

• Utilized digital subtraction angiography with contrast medium as an indicator substance.
• Performed 962 measurements using the Stewart-Hamilton dilution technique.
• Employed direct measurements of indicator bolus velocity between two sites.

Main Results:

• Stewart-Hamilton technique showed close correlation with true flow rates but a mean underestimation of 8%, attributed to contrast medium sedimentation.
• Bolus velocity measurements were most accurate when using specific points on the concentration curve, avoiding issues related to flow laminarity.
• Variations in repeated measurements were linked to the low sampling rate of the imaging system.

Conclusions:

• Computerized densitometry is a viable method for flow rate measurement in digital subtraction angiography.
• The Stewart-Hamilton technique requires consideration of potential contrast medium artifacts.
• Optimizing measurement points is essential for accurate bolus velocity assessments in laminar flow conditions.