Enhancement of abdominal Low-Dose CT image quality utilizing Clear View reconstruction technique at Mzuzu Central Hospital, Malawi

Abstract

Objective
This study aimed to investigate the impact of Clear View dual-domain iterative reconstruction (IR) technology on the quality of low-dose abdominal CT images and to determine the optimal weight ratio to optimize image quality.
Methods
We studied 40 patients (28 males, 12 females, aged 19-69) undergoing low-dose abdominal CT scans (CTDI = 5.32 ± 0.89 mGy). The scanning parameters were set as follows: tube voltage of 120 kVp, tube current modulation based on Signal to Noise Ratio (SNR) at 0.5 mode (O-Dose automatic tube current modulation technology), pitch of 0.9, rotation time of 0.6 s/r, matrix size of 512 × 512, and collimation width of 16 × 1.25 mm. We applied Clear View IR with four weight ratios (20%, 40%, 60%, 80%) and filtered back projection (FBP). Conventional scanning uses with 120 kVp, 280 mAs, pitch of 0.9, rotation time of 0.6 s/r, matrix size of 512 × 512, and collimation width of 16 × 1.25 mm. Conventional dose abdominal CT scans (CTDI = 11.95 ± 0.00 mGy).CT values, standard deviations (SD), signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were measured for liver, spleen, pancreas, kidneys, and erector spinae muscles. Two deputy chief physicians blindly evaluated image quality on a 1-5 scale. Statistical analysis was done using SPSS 22.0 with P < 0.05 considered significant.
Results
Subjective evaluations revealed the highest diagnostic score with a 40% Clear View reconstruction weight ratio. Higher weight ratios significantly reduced subjective image noise, with the highest noise scores at 80%. Moreover, compared to FBP, especially Clear View reconstruction weight ratios of 20% to 60%, significantly improved the image quality of abdominal solid organs, reducing image artifacts and improving diagnostic acceptability (P < 0.05). Objective evaluation showed that with increasing Clear View reconstruction weight ratios, image noise SD values decreased, while SNR and CNR values increased, and the differences in SD, SNR, and CNR for different reconstruction weight ratios of abdominal solid organs were statistically significant (P < 0.05).
Conclusion
Compared to FBP algorithm, Clear View demonstrates greater potential in low-dose abdominal CT, effectively reducing image noise and artifacts while maintaining image clarity. Based on combined subjective and objective evaluations, a 40% Clear View reconstruction weight ratio provides optimal image quality for abdominal solid organs.