Feasibility of 80-kVp CTA with reduced iodine contrast in chronic limb-threatening ischemia

Computed tomography angiography (CTA) is a vital preoperative diagnostic tool for chronic limb-threatening ischemia (CLTI). However, its high radiation dose and reliance on iodine contrast agents pose significant challenges, though studies addressing these challenges in CLTI remain limited. This study evaluates the feasibility of using 80-kVp tube voltage with reduced iodine contrast dosage in CTA for CLTI patients, aiming to minimize radiation exposure and contrast volume while preserving diagnostic image quality.

A total of 74 CLTI patients were prospectively enrolled and divided into 2 groups: the experimental group (n = 37) underwent CTA at 80 kVp with a contrast injection rate of 3.5 mL/s and a total volume of 75 to 85 mL; the control group (n = 37) was scanned at 120 kVp with a contrast injection rate of 4.0 mL/s and a total volume of 95 to 105 mL. Parameters including radiation dose (volume computed tomography (CT) dose index and dose-length product), iodine intake, and image quality (CT attenuation values, noise, signal-to-noise ratio, contrast-to-noise ratio, and subjective scores) were compared.

The experimental group demonstrated a 19.4% reduction in iodine intake (P < .05) and a 30.1% and 29.3% reduction in volume computed tomography dose index and dose-length product, respectively (P < .05), compared with the control group. The experimental group demonstrated significantly higher CT attenuation values and increased image noise across all measured levels (all P < .05), while maintaining comparable signal-to-noise ratio across all measured levels (all P > .05). Similarly, contrast-to-noise ratio remained equivalent between groups at the lower abdominal aorta, mid-femoral artery, and mid-popliteal artery levels (all P > .05). The subjective image quality scores showed no significant differences between the experimental and control groups, both above (4.70 ± 0.46 vs 4.74 ± 0.44, P = .43) and below (4.08 ± 0.57 vs 4.15 ± 0.60, P = .15) the popliteal artery level.

Lower-limb CTA using 80-kVp tube voltage and reduced iodine contrast dosage is feasible for CLTI patients, providing diagnostic image quality while significantly reducing radiation exposure and contrast volume. This approach offers a safer and more efficient alternative for preoperative evaluation in this population.