Introduction Non-contrast CT (NCCT) head is a standard imaging modality for evaluating central nervous system pathologies. Repeated CT brain examinations are associated with a cumulative risk of cancer development. Deep learning image reconstruction (DLIR) techniques help improve image quality (IQ) while reducing radiation dose (RD) compared with iterative reconstruction techniques (iDose 4 ). Therefore, our study compared IQ parameters among low-dose (LD) CT with DLIR (Precise Image), LD CT with iterative reconstruction (iDose 4 ), and standard-dose (SD) CT with iDose 4 and further evaluated radiation dose reduction between SD-iDose 4 and LD-DLIR in NCCT head imaging. Methods Group A (SD with iDose 4 ) and Group B (LD with DLIR; Precise Image) each included 96 patients. All NCCT brain scans were performed using a 128-slice incisive CT scanner (Philips Healthcare Systems) with iDose 4 and DLIR. Qualitative and quantitative IQ analyses and radiation dose indices were compared between the groups. Lesion conspicuity was also assessed between LD-DLIR and LD-iDose 4 . Results There was a significant reduction in RD (effective dose: 1.01 vs. 2.4 mSv; p 0.05) with LD-DLIR. LD-DLIR demonstrated superior IQ compared with both SD-iDose 4 and LD-iDose 4 . Subjectively, gray–white matter differentiation improved from scores of 3 (SD-iDose 4 ) and 2.5 (LD-iDose 4 ) to 4.5 (LD-DLIR), while overall image quality and subjective image noise increased from 3–3.5 (SD-iDose 4 ) and 2.5–3 (LD-iDose 4 ) to 4–4.5 with LD-DLIR ( p 0.05). Image noise was lowest with LD-DLIR in gray matter thalamus (GMT: 2.30–2.31) compared with SD-iDose 4 (4.80–4.85) and LD-iDose 4 (6.15–6.25); similar results were seen in the white matter posterior limb of the internal capsule (WMPIC: 1.98–2.21 vs. 4.36–4.38 vs. 5.19–5.32) and adjacent cortical gray matter (ACGM: 2.17–2.19 vs. 4.14–4.22 vs. 5.04–5.08). SNR was highest with LD-DLIR GMT: 16.29–16.36 vs. 7.32–7.34 (SD-iDose 4 ) and 5.61–5.75 (LD-iDose 4 ); WMPIC: 14.69–14.75 vs. 6.49–6.51 vs. 5.18–5.26, and contrast-to-noise ratio (CNR) was also markedly improved GMT–WMPIC: 2.59–2.61 (LD-DLIR) vs. 0.98–0.99 (SD-iDose 4 ) and 0.82–0.83 (LD-iDose 4 ); ACGM–FWM: 2.15–2.29 vs. 0.93–0.95 vs. 0.85–0.86. Lesion conspicuity was superior with LD-DLIR for all brain lesions compared with LD-iDose 4 . Conclusion Our study demonstrated that LD NCCT head imaging with DLIR provides superior noise reduction and improved GWMD, SNR, and CNR compared with SD and LD with iDose 4 and supports the clinical utilization of DLIR.
M. et al. (Tue,) studied this question.