Computed Tomographic Angiography of the Abdomen and Pelvis in Azotemic Patients Utilizing 80-kV(p) Technique and Reduced Dose Iodinated Contrast: Comparison With Routine 120-kV(p) Technique.

OBJECTIVE: To evaluate image quality (IQ) of a reduced contrast volume, low kilovolt (peak) [kV(p)] abdominopelvic computed tomographic angiography (AP-CTA) protocol compared to a standard 120-kV(p) AP-CTA protocol.

METHODS: A retrospective image analysis was performed on 103 patients with end-stage renal disease who underwent AP-CTA. Forty-nine patients were scanned at 80 kV(p) with a mean of 48 mL of contrast, and 54 patients were scanned at 120 kV(p) with a mean of 98 mL of contrast. Objective comparison of arterial attenuation, noise, and contrast-to-noise ratio was obtained, in addition to radiation dose. Subjective assessment of IQ, enhancement intensity, and image noise (IN) was scored on a 3-point scale.

RESULTS: The 6-level aggregate contrast-to-noise ratio for the 80-kV(p) group was 11.8 ± 7.0, compared to 12.4 ± 4.6 in the 120-kV(p) group (P = 0.210). Radiation exposure was significantly lower in the 80-kV(p) group versus the 120-kV(p) group, as measured by average CT dose index (mGy) of 9.0 ± 3.1 and 15.8 ± 5.8 (P < 0.0001), respectively; and average dose length product (mGy × cm) of 490.0 ± 214.1 and 863.1 ± 344.4 (P < 0.0001), respectively. The 120-kV(p) technique scored better for subjective IQ (P = 0.042) and IN (P = 0.004) but not for enhancement intensity (P = 0.205).

CONCLUSIONS: A 50% reduced iodinated contrast dose coupled with 80-kV(p) technique with iterative reconstruction allows for satisfactory AP-CTA studies at a 43% mean radiation dose reduction compared to a standard protocol. Negative but potentially reversible sequelae of this drop in radiation dose include increased IN and reduced subjective IQ.