[Studies on contrast medium dosage in perfusion-weighted MR imaging]

Area of Science:

• Radiology
• Medical Imaging
• Neuroimaging

Background:

• T2*-weighted sequences are crucial for MR perfusion imaging.
• Paramagnetic contrast agents enhance signal changes.
• Optimizing contrast agent dosage is key for accurate perfusion parameter mapping.

Purpose of the Study:

• To determine if increasing paramagnetic contrast agent dosage improves signal decrease in T2*-weighted perfusion sequences.
• To assess the impact of contrast agent dosage on the reliability of perfusion parameter maps.
• To establish an optimal contrast agent dosage for meaningful MR perfusion imaging.

Main Methods:

• Prospective study involving 30 patients (10 per group).
• Bolus injection of gadolinium-DTPA at 0.1, 0.2, and 0.3 mmol/kg body weight (BW).
• Acquisition of 40 T2*-weighted images per patient on a 1.0 T scanner, followed by perfusion parameter calculation.

Main Results:

• A contrast agent dosage of 0.1 mmol/kg BW resulted in insufficient signal decrease and low signal-difference-to-noise ratio (delta S/N), preventing reliable gray and white matter differentiation.
• Higher dosages (0.2 and 0.3 mmol/kg BW) yielded significant signal decrease and adequate delta S/N, enabling differentiation and reliable parameter map generation.
• Reliable differentiation of gray and white matter was achieved at dosages of 0.2 mmol/kg BW and higher.

Conclusions:

• A minimum contrast agent dosage of 0.2 mmol/kg BW is necessary for meaningful MR perfusion imaging at 1.0 T using the specified sequence.
• Higher contrast agent dosages improve the reliability of perfusion parameter maps by increasing signal decrease and delta S/N.
• The study highlights the importance of appropriate contrast agent dosing for diagnostic accuracy in MR perfusion studies.