Design of a birdcage array for lower extremity angiography

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Medical Device Engineering
• Radiology

Background:

• Lower extremity magnetic resonance angiography (MRA) is crucial for diagnosing peripheral vascular diseases.
• Optimizing coil performance is essential for improving image quality and diagnostic accuracy in MRA.

Purpose of the Study:

• To evaluate a novel coil array composed of multiple birdcage coils for bolus chase MRA of the lower extremities.
• To assess the efficacy of capacitive decoupling in mitigating signal leakage between adjacent coils.

Main Methods:

• A prototype coil array with four birdcage coils (two for thigh, two for calf) was constructed.
• Decoupling was achieved using shared capacitors, with performance evaluated via bench measurements and MR images.
• Signal-to-noise ratios (SNR) were compared to commercial coils, and contrast-enhanced imaging was performed on volunteers.

Main Results:

• Capacitive decoupling effectively reduced signal leakage between coils.
• Significant SNR improvements were observed: 84% for calf imaging and 53% for thigh imaging compared to a four-element array.
• Demonstrated successful peripheral MRA and parallel imaging with a two-fold acceleration.

Conclusions:

• Birdcage coil arrays are highly valuable for lower extremity imaging due to homogenous sensitivity and good SNR.
• Shared capacitors provide effective coupling control, enabling individual leg coverage for novel peripheral MRA signal reception.
• This coil design represents a significant advancement for peripheral vascular imaging.