Objective: To evaluate the utility of dual-energy spectral computed tomography (CT) and low-iodine intake in CT angiography (CTA) of deep inferior epigastric perforator (DIEP) flaps.
Methods: In this prospective study, 40 patients with a BMI <28.0 kg/m(2) underwent CTA examination for breast reconstruction and were randomly assigned into two groups (n=20 for each group) as follows: Group A was submitted to dual-energy spectral CT and iodixanol (270 mg I/mL) and Group B was submitted to conventional high iodine contrast agent iohexol (350 mg I/mL). The volume CT dose index (CTDIvol ) and dose length product were recorded and the effective dose (ED) was calculated. The best mono-spectrum images of Group A were selected according to the optimal contrast to noise ratio (CNR). Both mono-spectrum images of Group A and polychromatic images of Group B were used to reconstruct maximum intensity projection (MIP) and volume rendering (VR) images of the perforating artery, respectively. Two radiologists evaluated subjective image quality using a 4-point score. The diameter of the perforating artery, CT value and SD value for the common femoral artery were measured and the CNR was calculated. The total iodine intake and radiation doses of the two groups were calculated and compared.
Results: The best mono-spectrum energy with the optimal CNR of the perforating artery was 63 keV. The CT value of common femoral artery in Group A (380.96±42.75HU) was 7.40% higher than in Group B (354.71±42.01 HU) but with no statistical significance (P>.05). The CNR of the common femoral artery in Group A (23.84±6.73) was 6.88% lower than in Group B (25.60±6.20), with no significant difference (P>.05). The diameters of the perforator vessels were 2.44±0.15 and 2.49±0.14 mm, respectively, with no significant difference (P>.05). Subjective image qualities for the two groups were both good for diagnostics, and the scores for Group A and Group B were (3.88±0.28) and (3.93±0.18), respectively. The scores of the two radiologists were consistent (kappa=0.634). The effective radiation dose in Group A (9.09±0 mSv) was 10.62% lower than in Group B (10.17±1.91 mSv). The total iodine intake in Group A (27 000 mg) was 22.86% lower than in Group B (35 000 mg).
Conclusions: The combination of dual-energy spectral CT and low-iodine intake in CTA of DIEP flap examination with the optimal CNR technology can meet the requirements of clinical diagnostics, with a 22.86% reduction in total iodine intake and an 11.01% reduction in radiation dose.
© 2016 John Wiley & Sons Ltd.