Digital Variance Angiography in Lower-Limb Angiography with Metal Implants

Area of Science:

• Radiology
• Medical Imaging
• Interventional Cardiology

Background:

• Metal implants in patients can degrade angiographic image quality due to automated beam adjustments.
• Digital subtraction angiography (DSA) is the standard but can be affected by artifacts from implants.
• Digital variance angiography (DVA) has shown potential for superior image quality and contrast-to-noise ratio (CNR).

Purpose of the Study:

• To evaluate if DVA can overcome the image quality reduction caused by metal implants in lower-limb angiographies.
• To compare the effectiveness of DVA versus DSA in the presence of metallic artifacts.
• To assess the impact of DVA on contrast-to-noise ratio (CNR) and overall image quality.

Main Methods:

• Retrospective analysis of 85 lower-limb iodine contrast angiograms from 12 patients with metal implants.
• Processing of angiograms using DVA and comparison with standard DSA.
• Objective measurement of CNR and subjective evaluation of image quality by three experienced radiologists using Likert scales and paired comparisons.

Main Results:

• DVA demonstrated a median CNR ratio (CNR_DVA/CNR_DSA) of 1.84, indicating significantly higher CNR.
• Paired comparisons showed 84.5% preference for DVA images, with high interrater agreement (83.2%).
• Mean image quality scores were significantly higher for DVA (4.43) compared to DSA (3.64).

Conclusions:

• DVA significantly enhances image quality in lower-limb angiography when metal implants are present.
• The improved CNR with DVA suggests potential for reduced radiation exposure in such procedures.
• DVA represents a promising alternative to DSA for improving imaging in complex patient populations with implants.