Helical vs Conventional CT in Routine Head Imaging. A Comparison of Dose and Image Quality using VGC Analysis
Author(s): Dousi M, Fatsi A, Sotirakou K, Gkatzia N, Patelarou M, Theodosiou A
Purpose: To compare and evaluate the sequencial and helical head CT imaging acquisition nodes in terms of patient dose and image quality.
Material and Methods: Sixty patients were studied in total for one week from July 2018 to July 2019 and all underwent two head CT exams. The first time a conventional technique was used and the other one the helical technique. Scan parameters and dose indices were recorded on a checklist at the end of each examination. The images were rated by three radiologists according to the criteria of the European Guidelines on Quality Criteria for Computed Tomography.
Results: Mann-Whitney U test showed that both dose indicators CTDIvol and DLP were statistically higher (p<0.05) in helical (Mean CTDIvol=34.15, Mean DLP=532.47) than in conventional scanning mode (Mean CTDIvol=31.73, Mean DLP=464.91). According to our study, the helical technique recorded a higher dose in patients compared to the conventional one. Visual Grading Characteristics analysis showed that image quality based on criteria 1, 2, 4 is statistically higher (Criterion 1 AUCVGC=0.74, Criterion 2 AUCVGC=0.77, Criterion 4 AUCVGC=0.70, p<0.05) in conventional technique and does not differ in statistics based on criteria 3, 5 (Criterion 3 AUCVGC: 0.52, Criterion 5 AUCVGC=0.52, p>0.05). According to the AUCVGC, the scores of the conventional technique images were statistically significantly higher than the helical ones (AUCVGC=0.65, p<0.05).
Conclusions: The radiation dose from sequential scanning was found to be statistically lower than in the helical scanning. According to the AUCVGC the sequential acquisition mode produces images of superior image quality than helical acquisition mode.