Application of iDose in low-dose CT cardiac imaging in patients with congenital heart disease

Objective: To evaluate the value of iterative reconstruction (iDose) in low-dose CT cardiac imaging in patients with congenital heart disease (CHD). Methods: Eighty-eight consecutive CHD patients referred for preoperative or post-operative CT were randomly diveded into 4 groups and undergone a prospective ECG-gated MDCT angiography with protocol A (routine low-dose depending on patient weight), B (30% of A), C (50%), and D (70%D), respectively. Filtered back projection (FBP) and grades 2, 4, 6 of iDose were used for all reconstruction. Noises were measured at the root of ascending aorta and main pulmonary artery. Image qualities were graded (scale from one to five) and compared among 4 groups. Results: The lowest image noise was measured in images reconstructed with grade 6 of iDose(P < 0.05) while the highest one was measured in that with FBP in all groups. The subjective scores in Group D with iDose 6 reconstruction were no less than 3. The subjective score in Group D with iDose 6 was similar to that in Group A with FBP. Effective radiation dose in group D was (0.65±0.43) mSv. Conclusion: Using iDose technique would reduce noise and improve image quality effectively. Grade 6 of iDose might be the best choice and would reduce effective dose by 70% in MDCT angiography in CHD patients. (authors)