Dose-wise scanning in visceral computed tomography angiography: a phantom study.

Area of Science:

• Medical Imaging
• Radiology
• Vascular Imaging

Background:

• Accurate stenosis quantification is crucial for diagnosing occlusive vascular disease.
• Multidetector computed tomography angiography (MDCT) is a key imaging modality for vascular assessment.
• Optimizing imaging parameters is essential for balancing diagnostic accuracy and radiation dose.

Purpose of the Study:

• To evaluate the impact of tube current-time product (IAP) in MDCT angiography on stenosis quantification accuracy.
• To determine the feasibility of dose reduction in phantom models of occlusive vessel disease.

Main Methods:

• Simulated stenosed pelvic and visceral arteries using acrylic tubes with varying plaque compositions and degrees of stenosis.
• Acquired images using 8 different IAPs on a 64-slice MDCT scanner.
• Correlated measured luminal area with known values using the Kappa-Lin test and calculated sensitivity and specificity for hemodynamically relevant stenoses.

Main Results:

• High correlation (κLin = 0.91-0.95) for large vessels with IAP80-IAP280, and substantial correlation (κLin = 0.89-0.82) for small vessels with IAP120-IAP280.
• Best correlation observed in calcified (κLin = 0.95) and soft (κLin = 0.93) plaques.
• Sensitivity for hemodynamically relevant stenoses remained high (90%-99%) across IAPs, while specificity decreased with lower IAPs, particularly in smaller vessels.

Conclusions:

• Substantial dose reduction is feasible in large vessel phantoms (>6.5 mm) without compromising accuracy.
• In smaller vessel phantoms (<4.0 mm), spatial resolution limits luminal delineation, restricting the extent of acceptable dose reduction.
• Optimizing IAP is critical for accurate stenosis quantification and dose optimization in MDCT angiography.