Impact of optional reconstruction kernel on image quality of pulmonary ground glass nodules using the third generation dual-source computed tomography / 中南大学学报(医学版)

To explore the value of the third generation dual-source computed tomography (CT) convolution kernel in display of pulmonary ground-glass nodule (GGN) in transverse image reconstruction.
 Methods: A total of 52 lung adenocarcinoma patients with lung CT data were selected from February 2018 to January 2019 for this study. The pulmonary CT data were reconstructed by convolutional nucleus B157, Br54, and Br49. The signal-to-noise ratio (SNR), the contrast-to-noise ratio (CNR), and the standard deviation (SD) of the image at the GGN were used as the objective evaluation standard of image quality. Subjective image quality was scored by 2 radiologists from 3 aspects (overall image quality, noise, and lesion outline).
 Results: Objective image quality evaluation, SNR and CNR of reconstructed convolution kernel Br49 (SNR: 11.36±5.39, CNR: 7.19±4.29), Br54 (SNR: 8.30±3.35, CNR: 5.09±2.86) are greater than those of Bl57 (SNR: 4.18±2.10, CNR: 3.25±1.78; all P<0.01). SD of reconstructed convolution kernel Br49 (61.80±20.17) and Br54 (80.45±20.31) is smaller than that of Bl57 (137.92±31.11, both P<0.01). In the subjective image quality evaluation, the overall image quality score 5.0(4.5, 5.0) of Br54 was higher than that of all other images [Br49: 3.0(3.0, 4.0), Bl57: 3.0(3.0, 3.5); both P<0.05]. The Br54 image showed that the lesion contour ability score 5.0(4.0, 5.0) was higher than all other images [Br49: 4.0(4.0, 5.0), Bl57: 3.0(3.0, 3.0); both P<0.05]; Br49 image noise score 3.0(3.0, 3.0) is the lowest one [Br54 4.0(4.0, 4.0), Bl57 5.0(5.0, 5.0); both P<0.05].
 Conclusion: The reasonable selection of CT convolution kernel plays an important role in the subjective and objective image quality of GGN. It is suggested that Br54 should be used as the reconstruction of convolutional kernel in pulmonary ground glass nodules, which is helpful for doctors to find and diagnose GGN.

Effect of a noise-optimized virtual monoenergetic reconstruction technique on dual-energy CT for image quality of inflammatory bowel disease / 中南大学学报(医学版)

To assess the value of noise-optimized virtual monoenergetic imaging (VMI+) reconstruction technique on objective and subjective image quality in patients with inflammatory bowel disease (IBD) undergoing abdominal dual-energy computed tomography (DECT).
 Methods: Datasets from 32 patients (22 men, 10 women) with IBD, who underwent abdominal DECT, were reconstructed by using the standard linearly blended (M_0.6), traditional monoenergetic (VMI) and VMI+ algorithms in 10-keV intervals from 40-100 keV. Attenuation in IBD lesions was measured to perform objective evaluation using signal-to-noise (SNR) and contrast-to-noise ratios (CNR). Subjective evaluation was performed by 3 independent blinded radiologists using 5-point Likert scales. The overall image quality, image sharpness, lesion delineation, and image noise were analyzed. 
 Results: Mean SNR and CNR peaked at 40 keV VMI+ series (SNR 8.28±2.34, CNR 5.10±2.10) and they were significantly higher than those in linearly blended (SNR 5.82±1.44, CNR 1.53±0.86) and all VMI series (all P<0.01). Subjective image parameter was the highest for the 50 keV VMI+ series regarding overall image quality (mean 4.80, all P<0.01). The highest image sharpness scores were observed at 40 and 50 keV VMI+ reconstructions (mean 4.14 and 4.25, respectively; P=0.415). VMI+ series at 40 keV provided the highest lesion delineation (mean 4.52, all P<0.01). Image noise was low at the 100 keV VMI+ and VMI series (mean 4.58 and 4.40, respectively; P≥0.11).
 Conclusion: Low-keV VMI+ reconstructions improves SNR, CNR, and subjective image quality significantly in patients with IBD.