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Correlation between dose rate and T1 in blood at Gd-enhanced MR angiography
1Department of Diagnostic Radiology, Uppsala University Hospital, Sweden.
Purpose:
To determine the correlation between dose rate and T1 in blood at Gd-enhanced MR angiography (MRA).
Material And Methods:
A test dose of contrast agent was used to calculate the time delay between injection and arrival in the abdominal aorta. The dose rate was expressed as ml.kg b.w.-1.s-1. The correlation between dose rate and T1 was determined by varying the dose rate while keeping the scanning and infusion times constant. The signal intensity in the abdominal aorta was measured during the first pass of Gd and compared with markers of known T1 values.
Results:
A correlation between dose rate and T1 in blood was obtained.
Conclusion:
A Gd dose rate of 0.01 ml.kg b.w.-1.s-1 gives a T1 in blood of 100 ms. This can be used to calculate the optimal pulse sequence for contrast-enhanced MRA.
Insights
A correlation between gadolinium (Gd) dose rate and blood T1 was found. A Gd dose rate of 0.01 ml/kg/s yields a T1 of 100 ms, aiding optimal contrast-enhanced MR angiography (MRA) pulse sequence calculation.
Area of Science:
- Medical Imaging
- Radiology
- Magnetic Resonance Imaging
Background:
- Gadolinium-enhanced Magnetic Resonance Angiography (MRA) relies on contrast agent properties.
- Understanding the relationship between contrast dose and blood relaxation time (T1) is crucial for optimizing image quality.
Purpose of the Study:
- To establish the correlation between gadolinium (Gd) dose rate and blood T1.
- To determine the optimal Gd dose rate for contrast-enhanced MRA.
Main Methods:
- Calculated injection-to-arrival time delay using a test dose.
- Expressed dose rate in ml.kg b.w.-1.s-1.
- Measured signal intensity in the abdominal aorta during first pass of Gd, comparing with known T1 markers.
Main Results:
- A direct correlation between Gd dose rate and blood T1 was established.
- Identified a specific Gd dose rate yielding a target blood T1.
Conclusions:
- A Gd dose rate of 0.01 ml.kg b.w.-1.s-1 results in a blood T1 of 100 ms.
- This finding enables calculation of optimal pulse sequences for contrast-enhanced MRA.