Application of deep learning image reconstruction algorithm in low-dose abdominal CT / 西安交通大学学报(医学版)

【Objective】 To investigate the value of deep learning image reconstruction (DLIR) in improving image quality and reducing beam-hardening artifacts of low-dose abdominal CT. 【Methods】 For this study we prospectively enrolled 26 patients (14 males and 12 females, mean age of 60.35±10.89 years old) who underwent CT urography between October 2019 and June 2020. All the patients underwent conventional-dose unenhanced CT and contrast-enhanced CT in the portal venous phase (noise index of 10; volume computed tomographic dose index: 9.61 mGy) and low-dose CT in the excretory phase(noise index of 23; volume computed tomographic dose index: 2.95 mGy). CT images in the excretory phase were reconstructed using four algorithms: ASiR-V 50%, DLIR-L, DLIR-M, and DLIR-H. Repeated measures ANOVA and Kruskal-Wallis H test were used to compare the quantitative (skewness, noise, SNR, CNR) and qualitative (image quality, noise, beam-hardening artifacts) values among the four image groups. Post hoc comparisons were performed using Bonferroni test. 【Results】 In either quantitative or qualitative evaluation, the SNR, CNR, overall image quality score, and noise of DLIR images were similar or better than ASiR-V 50%. In addition, the SNR, CNR, and overall image quality scores increased as the DLIR weight increased, while the noise decreased. There was no statistically significant difference in the distortion artifacts (P=0.776) and contrast-induced beam-hardening artifacts (P=0.881) scores among these groups. 【Conclusion】 Compared with the ASiR-V 50% algorithm, DLIR algorithm, especially DLIR-M and DLIR-H, can significantly improve the image quality of low-dose abdominal CT, but has limitations in reducing contrast-induced beam-hardening artifacts.

The effect of CT reconstruction kernels and display window settings on the detection and measurement of pulmonary solid nodules / 西安交通大学学报(医学版)

【Objective】 To assess the effect of reconstruction kernels and window settings on the detection and measurement of pulmonary solid nodules and their measurement variability and repeatability. 【Methods】 We retrospectively recruited 49 patients with pulmonary solid nodules who had undergone low-dose CT scanning. Images were reconstructed using five reconstruction kernels： lung， bone， chest， detail and standard kernels. Two radiologists independently assessed the detection rate， diameter and CT number measurement of nodules under the five kernels and two window settings （lung-window and mediastinal-window）. Bland-Altman plots and relative average deviation （RAD） were used to evaluate the repeatability and variability of nodule diameter and CT number measurement. 【Results】 Seventy-seven nodules were detected on lung-window regardless of reconstruction kernels， while the detection rates （75.3%-98.7%） were significantly different （P<0.001） on the mediastinal-window， with the lung kernel significantly improving the detection of nodules with the diameter below 6 mm. In both display windows， the diameter and CT number measurements among reconstruction kernels were similar except for the lung kernel. The lung-window had better variability in the diameter measurement while mediastinal-window was better in CT number measurement among various reconstruction kernels. Although the variability in the diameter of the nodule on the lung-window and mediastinal-window was similar， there was a significant difference in the variability in the diameter measurement among different reconstruction kernels on the mediastinal-window （P=0.004）. No significant difference in the variability in the CT number measurement was found among the different reconstruction kernels （lung-window P=0.163； mediastinal-window P=0.201）， and the variability in the CT number measurements on the mediastinal-window was smaller than that of the lung-window. Both window displays had acceptable repeatability in diameter and CT number measurement； however， the mediastinal-window was better in CT number measurement. 【Conclusion】 The lung kernel can improve the detection of pulmonary solid nodules below 6 mm， but is limited in the CT number measurement. The lung-window display provides better variability in measuring nodule diameter， while mediastinal-window display is better at measuring CT numbers.

CT diagnosis of parovarian cyst / 实用放射学杂志

Objective To investigate the CT performances and causes of misdiagnosis of parovarian cyst,to improve its diagnostic accuracy.Methods CT data of 75 patients with surgically and pathologically confirmed parovarian cyst were analyzed retrospectively. Results Among the 75 patients,there were 79 cysts,in which 48 patients (51 cysts)originated from the epoophoron and 27 patients (28 cysts) from the mesosalpinx.77 were simple serous cysts and 2 serous cystadenomas.38 were located in the right ovarian adnexa,36 in the left ovarian adnexa,3 in the anterosuperior uterus,1 in the rectouterine pouch and 1 in the right iliac fossa.The size of the cysts ranged from 10 mm × 13 mm to 174 mm × 227 mm.75 were single cysts and 4 double cysts,34 presented as ovoid cysts,25 as irregular cysts, 17 as round cysts and 3 as gourd-shaped cysts.All the 79 cysts showed clear boundaries,thin walls,non-mural nodules,cystic fluid with a homogeneous densitywith CT value of 0-31 HU.Enhanced scanning revealed curved “obvious enhancement of the fallopian tube”at the edge of 68 cysts.In addition,the ipsilateral ovary could be detected in 76 cysts.“Holding ball”was found in 1 9 cysts.Conclusion Indication in ipsilateral ovary,curved “obvious enhancement of the fallopian tube”at the edge of cysts and “holding ball”are distinctive CT performances of parovarian cysts.CT has an important diagnostic value in parovarian cyst.

Treatment of periprosthetic femoral fractures with unstable prosthesis by replacement of long-stem femoral prosthesis / 中华创伤骨科杂志

Objective To discuss the treatment of periprosthetic femoral fractures (PFF) with unstable prosthesis by replacement of long-stem femoral prosthesis and internal fixation.Methods From December 2005 to December 2014,15 PFF patients with unstable prosthesis (15 hips) following were treated at our department.They were 10 men and 5 women,aged from 64 to 89 years (mean,76.2 years).Their primary surgeries included total hip arthroplasty in 13 cases and biological bi-polar replacement of femoral head in 2.Two prostheses were cement and 13 biological.By Vancouver classification,9 cases were type B2,and 6 type B3.The unstable prostheses in the 15 cases were replaced by long-stem femoral ones,followed by internal fixation.At the last follow-ups,clinical outcome were evaluated by Harris scoring and images of PFF by Beals & Tower criteria.Complications were documented.Results One died 4 months after operation.The other 14 patients were followed up for an average of 4.5 years (from 6 months to 9 years).Fracture union was achieved in 12 cases after an average of 3.9 months (from 3 to 9 months).Nonunion occurred in 2 cases.Imaging evaluation revealed 9 excellent cases,3 good ones and 2 poor ones.The Harris scores at the last follow-up averaged was 82.3 points (from 50 to 100 points).Deep vein thrombosis occurred preoperatively in one case and posterior tibial vein thrombosis occurred in 2 cases respectively on day 3 and day 10 postoperatively.No such complications occurred as malunion,fixation failure,dislocation or prosthesis loosening.Conclusion Satisfactory outcomes can be achieved by replacement of long-stem femoral prosthesis combined with appropriate fixation for treatment of PFF with unstabrosthesis.

Extrapleural locating method: significance in CT-guided transthoracic pulmonary biopsy / 中华放射学杂志

Objective To evaluate the usefulness of extrapleural locating method in CT-guidod transthoracic pulmonary biopsy to prevent or reduce the size of peumothorax.Methods One hundred and fifteen cases of CT-gnided transthoracic pulmonary biopsy with the pulmonary lesions not in direct contact with the pleura were selected.Of 115 cases,46 were performed with extrapleural locating method (EPL) and 69 cases with lesion edge locating method (LEL).Taking the maximum distance between the partial and visceral pleura (MPVD) measured on the CT image after the procedure as the index of the volume of pneumothorax.The incidence and volume of pneumothorax of both groups were compared and statistically analysed with R ×C Chi-Square test.The retention time of the biopsy needle in the lung parenchyma of the two group was documented and the average time was calculated in each group.Results The incidence of pneumothorax was 45.7% (21/46),median 0.4 cm with EPL group,and 66.7% (46/69) and median 0.3cm with LEL group.When the distance between the lesion and pleura was equal or smaller than 2 cm (≤2cm),the incidence of pneumothorax was 39.4% (13/33) with EPL group and 73.2% (30/41) with LEL group,and the difference of incidence and volume of the pneumothorax between two groups was statistically signifieant(X2 =9.981,P =0.019).When the distance was larger than 2 cm( >2 cm),the incidence and volume of pneumothorax between two groups were not significant statistically.The average retention time of the biopsy needle in the lung parenchyma was (7.2±1.8)s with EPL group and (58.3±11.6) s with LEL group.Conclusion The extrapleural locating method can reduce effectively the retention time of the biopsy needle in the lung parenchyma and the incidence and volume of pneumothorax in CT-gnided transthoracic pulmonary biopsy.