ISSN 1004-4140
CN 11-3017/P

## 2019 Vol. 28, No. 1

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2019, 28(1): 1-11. doi: 10.15953/j.1004-4140.2019.28.01.01
Abstract(457) PDF(13)
Abstract:
Flat-panel detector based cone beam computed tomography (CBCT) dental medical imaging (dental CBCT) possesses the characteristics as X-ray beam wide-collimated at Z direction (refer to direction parallel to CT rotation axis), 180 to 360 degree selectable scan angle range, adjustable field of view size, and selectable full-fan or half-fan detector offset modes. Absorbed dose distributions in patient's head caused by dental CBCT are more complex than that caused by multi-detector CT (MDCT) and other clinical CBCTs (eg. CBCT applied to image-guided radiotherapy and interventional surgery etc.). Therefore, an effective and agreed internationally dental CBCT dose estimation mode has not been raised yet. This paper reviews researches on CT dose estimation, and concludes that dental CBCT dose estimation mode consists two interacted layers of dose index and patient medical radiation dose (which indicates effective dose based on population mean dataset and patient specific organ dose). Meanwhile, this review reaches results as follows. The key problem for dental CBCT dose index is how to depict absorbed dose distributions at phantom central plane being vertical to Z direction when an uniform cylindrical phantom is scanned. Area average absorbed dose is the most promising dose index to this problem. Dental CBCT can apply MDCT's patient medical radiation dose estimation theories directly, except for one problem remains to be solved. That is how to get exact patient's attenuation information for specific X-ray source. Meanwhile, dental CBCT dose estimation mode should explore the influence caused by heel effect and cone angle effect of cone shape X-ray beam.
2019, 28(1): 13-28. doi: 10.15953/j.1004-4140.2019.28.01.02
Abstract(341) PDF(11)
Abstract:
In recent years, the acoustic reflection imaging logging technique (ARILT) has become a research hotspot in evaluation of fractures and holes reservoirs close to borehole. The conventional ARILT can generally detect structures within 20 meters, and has certain limitations on describing complex structural boundaries. In this paper, the least-square reverse time migration (LSRTM) is introduced into ARILT on the premise of matching logging observation systems and calculation parameters, which will improve the effective imaging range and imaging precision nearby the well area. Based on the realization of migration algorithms and processing flows, the article applies the algorithms to typical models and one actual data, and focuses on analyzing the imaging effects of different frequencies, depths and migration methods. It is found by comparing the imaging results that (1) the effective imaging algorithms are the key to the imaging accuracy of ARILT. LSRTM not only has a high resolution, but also can reveal the horizontal change of the structures; (2) Excitation source's frequency is an important factor affecting the resolution of imaging as the result that the higher the frequency, the higher the image resolution, but the high frequency will lose detecting depth; (3) LSRTM can effectively detect structures within 23 meters under the given logging observation parameters in this paper.
2019, 28(1): 29-38. doi: 10.15953/j.1004-4140.2019.28.01.03
Abstract(369) PDF(8)
Abstract:
Objective: To study the clinical, pathological and CT features of patients with multiple primary lung cancer (MPLC), analyze its prognosis and survival related factors, and provide theoretical basis for its clinical diagnosis, treatment and prognosis evaluation. Methods: A total of 93 MPLC patients diagnosed in our hospital from 2009-01-01 to 2014-12-31 with at least 3 years of follow-up data were reviewed. The clinical, pathological and CT data of the patients were analyzed, and survival analysis was performed. Results: Among the 93 patients, 86(92.5%) had synchronous multiple primary lung cancer and 7(7.5%) had metachronous multiple primary lung cancer. There were 47 males (50.5%) and 46 females (49.5%) with ages from 39 to 79 years ($\tilde x$=58 years). Of the 93 patients, 33 cases (35.5%) had a history of smoking; 22 cases of emphysema (23.7%) 62 cases (66.7%) were in stageⅠ, 12 cases (12.9%) in stageⅡ, 15 cases (16.1%) in stage Ⅲ, 4 cases (4.3%) in stage Ⅳ. A total of 205 primary tumor lesions were found in 93 patients, mainly adenocarcinoma (94.2%), with diameters of 0.4~8.3cm ($\tilde x$=1.9cm). CT mainly manifested as double primary lung cancer (81.7%), 48 cases (51.6%) showed solid nodules/masses with GGN, and 30 cases (32.3%) were multiple GGN. Lobulation were found in 72.2% cases, speculation sign in 57.6% cases, vascular bundle sign in 56.1% cases, and pleural indentation in 61.0% cases. The 3-year overall survival rate after surgery was 94.6% and the disease free survival rate was 84.9%. Smoking history (P=0.016), maximum tumor diameter (P=0.036), pleural indentation (P=0.045) and bronchial truncation sign (P=0.024) were independent risk factors for disease-free survival of MPLC patients. Conclusion: Adenocarcinoma was the main pathological type among MPLC. The largest lesion had the malignant characteristics of primary lung cancer, particularly the presence of single or multiple GGN. The overall prognosis of MPLC is good. Smoking history, tumor size, pleural indentation and bronchial truncation sign are independent risk factors influencing the prognosis of patients. Early diagnosis and surgical treatment may achieve better prognosis.
2019, 28(1): 39-44. doi: 10.15953/j.1004-4140.2019.28.01.04
Abstract(290) PDF(8)
Abstract:
Objective: To analyze and compare the effect of computer-aided and artificially low dose CT in early lung cancer screening, and to provide theoretical basis for the selection of screening methods for early lung cancer. Methods: Low dose CT scans were performed on 256 high-risk patients with early lung cancer in our hospital from December 2015 to December 2017. Results: There were 42 patients of pulmonary nodules performed by low-dose CT, and the detection rate was 16.4%. There were 43 patients with pulmonary nodules detected by computer-assisted technique (manual error correction), and the detection rate was 16.8%. The difference was no statistically significant (χ2=0.014, P=0.905). There was a high consistency between manual interpretation and computer-assisted detection of high-risk patients (k=0.986). The working time of computer aided technology is lower than that of manual interpretation, saving about 70% of the working time (59.95±12.93) vs. (194.98±70.61) s, t=30.474, P=0.000). Conclusion: In this study, it was found that the efficiency of low-dose CT for early lung cancer screening with computer assisted (manual error correction) was significantly better than that of manual interpretation.
2019, 28(1): 45-52. doi: 10.15953/j.1004-4140.2019.28.01.05
Abstract(327) PDF(5)
Abstract:
Objective: The course of mandibular nerve canal in mandibular posterior region was judged by MSCT, which provided theoretical support for preoperative evaluation of mandibular posterior region implantation. Methods: MSCT data of 60 adult mandibles were collected to measure the distance of mandibular neural tube from the surrounding bone wall in the posterior tooth area and to compare and analyze the difference between male and female and between left and right sides. Results: The vertical distance from the upper margin of mandibular neural tube to the alveolar crest of mandible ranged from (13.21±1.73) mm to (18.03±1.73) mm, Except for the mental foramen area, there was statistical difference in gender, and no statistical difference between the left and right side. The vertical distance from the inferior margin of the mandibular canal to the inferior margin of the mandible ranged from (15.57±1.51) mm to (8.41±1.35) mm. There was statistical difference in genderand no statistical difference between the left and right side. The horizontal distance from the lateral margin of the mandibular canal to the buccal bone plate of the mandible ranged from 0 mm to (8.01±1.33) mm. The mean distance from the medial margin of the mandibular canal to the lingual bone plate ranged from (7.91±1.03) mm to (2.52±0.49) mm. There was no statistical difference in gender or left and right. Conclusion: MSCT can accurately reflect the course of mandibular canal; When implanting in the posterior mandibular region, the length of the implant is between 10 and 15 mm, which is relatively safe.
2019, 28(1): 53-60. doi: 10.15953/j.1004-4140.2019.28.01.06
Abstract(425) PDF(8)
Abstract:
Objective: To investigate the relationship between cartilage injury of knee tibiofemoral and femoral angle, tibial angle, femorotibial angle and joint space angle of knee joint. Methods: A retrospective analysis was made of 587 patients who underwent knee joint MRI examination in the Southern Hospital of Chengde Medical College from January 2017 to June 2017. 100 patients in the case group and 100 patients in the control group were randomly selected through inclusion and exclusion criteria. The femoral angle, tibial angle, femorotibial angle and joint space angle were measured in two groups, and the correlation angle data were statistically analyzed by SPSS19.0. The statistical methods included rank sum test, Spearman correlation test and ROC curve. Results: The femur angle, tibial angle, femorotibial angle and joint space angle of the case group were 83.22 (81.85 to 84.40) degrees, 95.60 (94.10 to 96.87) degrees, 179 (177.50 to 180.25) degrees and 1.92 (1.43 to 2.43) degrees, respectively. The femoral angle, tibial angle, femur tibial angle and joint clearance angle of the control group were 82.50 (81.70 to 83.60) degrees, 94.25 (93.20 to 95.52) degrees, 177.20 (175.90 to 178.17) degrees and 175.90 (0.50 to 0.95) degrees. There were significant differences in tibial angle, femorotibial angle and joint space angle between the two groups (P<0.05), but there was no significant difference in femoral angle (P>0.05), cartilage injury was positively correlated with the joint space angle (rs=0.852, P<0.001), but not with tibial angle and femorotibial angle. The optimal threshold value, sensitivity and specificity of tibial angle were 95.15 degrees, 56% and 72%, respectively. The optimum critical value, sensitivity and specificity of femorotibial angle were 179.05 degrees, 49% and 92% respectively, and the optimum critical value, sensitivity and specificity of joint space angle were 1.255 degrees, 84% and 96%, respectively. Conclusion: The increase of tibial angle, femorotibial angle and joint space angle will affect the tibiofemoral joint cartilage and lead to the injury of tibiofemoral joint cartilage. And with the increase of joint space angle, the injury degree of the tibiofemoral joint cartilage is aggravated.
2019, 28(1): 61-72. doi: 10.15953/j.1004-4140.2019.28.01.07
Abstract(283) PDF(6)
Abstract:
Objective: To compare the imaging quality of different levels of the adaptive algorithm of iterative reconstruction (ASiR) in abdominal venous optimal single energy image to optimize imaging parameters of abdominal vein. Materials and Methods: Retrospective analysis was performed on 30 patients who underwent CT upper abdomen enhancement scan. All the subjects were scaned with spectral model and optimal single energy images were calculated using postprocessing workstation, and then reconstructed with ASiR 30%, ASiR 40% and ASiR 50% algorithm respectively. Finally, three group images of different ASiR levels were acquired. The CT value, image noise, contrast noise ratio (CNR) and signal noise ratio (SNR) of all abdominal vein were compared among the images of the three single energy groups and one mixed energy group by using single factor analysis of variance (ANOVA). The data of four groups were subjectively evaluated by two professional diagnostic physicians using double blind method. Results: The original spectral CT data were processed to acquire the 65 keV images, which were reconstructed with 30% ASiR, 40% ASiR and 50% ASiR, respectively. Together with the mixed energy group, finally four groups were obtained. There were statictically significant differences of CT value, image noise, CNR and SNR between the mixed energy group and the other three single energy groups (P<0.01). There was no significant difference in CT value among 30% ASiR group, 40% ASiR group and 50% ASiR group (P>0.05). For the portal vein trunk, mesenteric vein and splenic vein, there were significant differences of image noise, CNR and SNR between the 30% ASiR group and the 50% ASiR group (P<0.05), while no differences of that parameters between the 30% ASiR group and the 40% ASiR group, as well as 40% ASiR group and the 50% ASiR group (P>0.05); For the inferior vena cava trunk, the left renal vein, the right renal vein, the left hepatic vein, the middle hepatic vein and the right hepatic vein, there were significant differences of image noise and CNR between the 30% ASiR group and the 50% ASiR group (P<0.05), while no differences of that parameters between the 30% ASiR group and the 40% ASiR group, as well as 40% ASiR group and the 50% ASiR group (P>0.05); There were significant differences of SNR among the three groups (P<0.05). Conclusion: For the abdominal veins, the imaging quality of the optimal single energy (65keV) +40% ASiR is better than that of the 65keV+30% ASiR, 65keV+50% ASiR and the mixed energy group, which can be widely used in clinical abdominal venous angiography.
2019, 28(1): 73-79. doi: 10.15953/j.1004-4140.2019.28.01.08
Abstract(315) PDF(5)
Abstract:
Objective: To investigate the image quality and radiation doses resulting from abdominal CTA when using low concentration contrast combined with low kV. Methods: 90 patients from our hospital during 2017 Jan. to 2018 Jun. were chosen for our study. The patients were divided into two groups: Group A: normal doses (120kV, 370mgI/mL), Group B: low doses group (100kV, 270mgI/mL). Group A and Group B were subdivided into three subgroups according to their BMI: A1, B1 (BMI<24), A2, B2 (2428). 100mL contrast medium was injected at the speed of 4mL/s, after then, 20mL saline was added. The CT value and CNR of abdominal aorta, common hepatic artery, splenic artery, superior mesenteric artery and right renal artery, were evaluated by both doctors and system. The data were analyzed by SPSS16.0 software. Results: no significant difference were found in CT value or CNR of abdominal aorta, common hepatic artery, splenic artery, superior mesenteric artery and right renal artery (P>0.05). However, the radiation doses were much lower in low dose group compared with normal group (P<0.05). We also found a negative correlation between CNR and BMI value in low dose group, but not in normal group. Conclusion: There is no difference in image quality or CT value between normal group and low group. Radiation doses were significantly reduced in low doses group.
2019, 28(1): 81-90. doi: 10.15953/j.1004-4140.2019.28.01.09
Abstract(297) PDF(10)
Abstract:
Objectives: To evaluate the consistency of energy spectrum CT virtual non-contrast and non-contrast scan on the density of subsolid lung adenocarcinoma (CT value); and the value of enhancement scan on the invasiveness of subsolid lung adenocarcinoma. Methods: 46 patients with subsolid nodules on chest CT first time and then scanning spectrum CT enhancement. A total of 45 nodules with pathologically confirmed lung adenocarcinoma and precancerous lesions were enrolled in 39 patients. Obtain virtual non-contrast images at the workstation, compare the average HU values of the regions of interest in the lesions, surrounding normal lung tissue and paravertebral muscles. According to the prognosis and invasiveness, divided into the precancerous lesions, the minimally invasive adenocarcinoma group and the invasive adenocarcinoma group, which compared there difference. Results: There was no significant difference between the non-contrast and virtual non-contrast of the surrounding normal lung tissues and paravertebral muscles, which were highly correlated. There was no significant difference in HU and iodine concentration. There was no positive results in the invasiveness of lung adenocarcinoma between the groups of the precancerous lesions, the minimally invasive adenocarcinoma and the invasive adenocarcinoma. Conclusion: There was no statistically significant difference between the energy spectrum CT virtual non-contrast HU value and the non-contrast scan. The enhancement scan had no positive results in identifying the invasiveness of lung adenocarcinoma in this group.
2019, 28(1): 91-98. doi: 10.15953/j.1004-4140.2019.28.01.10
Abstract(299) PDF(7)
Abstract:
In order to accurately detect the underground distribution of burning rock and fissure water in open pit coal mine, a comprehensive electromagnetic detection method based on magnetic field intensity and resistivity is proposed, because different occurrence conditions groundwater has electromagnetic difference. Taking an open-pit coal mine in Xinjiang as an example, the boundary of the burnt rock is determined by the intensity parameter of magnetic anomaly, the low resistivity area at different depths is delineated by resistivity method combined with high-density electrical method and transient electromagnetic method, the distribution of burning rock water and fissure water is deduced separately according to geological conditions. The accuracy of the detection results is verified by ground drilling. The results show that the electromagnetic response of groundwater in the burning rock and fissure development area of open pit coal mine is obviously different, and the distribution range can be accurately delineated based on the two parameter comprehensive electromagnetic method according to the magnetic field intensity and resistivity.
2019, 28(1): 99-110. doi: 10.15953/j.1004-4140.2019.28.01.11
Abstract(317) PDF(7)
Abstract:
Broadband, wide azimuth and high density data acquisition are ever growing trend of seismic exploration in recent years. Conventional acquisition equipment and geometry scheme have been unable to meet the technical requirements for this development. With the reliability of modern electronic equipment greatly improved. On the premise of ensuring production efficiency and reducing acquisition cost, the updated seismic acquisition equipment makes high-density acquisition possible and meets the needs of deep exploration and high-precision exploration. This paper focuses on the technical improvement of land seismic acquisition of vibrator (Nomad series) and digital sensor (dsu1-508) and analyses the processing seismic results of high-density acquisition compared with that of conventional acquisition. The results showed that the new generation of equipment greatly improved the imaging quality while widening the frequency band and improving the resolution.
2019, 28(1): 111-120. doi: 10.15953/j.1004-4140.2019.28.01.12
Abstract(378) PDF(3)
Abstract:
Objective: To explore the feasibility and methods of reducing the tube current personalized based on the waistline in Multislice spiral CT examination of thoracolumbar trauma. Methods: the CT model of 55~120cm waistline was obtained from bovine lumbar segments. The vertebral body was scanned with 25~300mA and other scanning parameters were un-changed. The tube current value was obtained when the image quality was standard. First 131 non traumatic cases of lumbar CT examination were scanned for the normal and low dose conditions, and the suitable low dose scanning conditions were screened. 43 cases of thoracolumbar trauma centrums were scaned for the routine and screening low dose scanning. The images of faults and MPR and VR and MIP were comparatively analyzed. Results: the correlation between the current of CT scanning tube and the waist circumference is high; the correlation coefficient of Pearson is 0.994. The regression equations y=1.053x-33.187, R2=0.984 was derived with the tube current as argument and waistline as the dependent variable. The dose of low dose scanning was significantly lower than that of the conventional dose scanning; the image quality in the bone cortex, the spinal canal structure, the spinal canal soft tissue and the overall image quality (bone window and soft tissue window) was significantly different from that of the conventional dose group, but their scores were all good and acceptable; The good rate of VR and MIP reached 93%. Conclusion: the examination of thoracolumbar trauma on low-dose multislice spiral CT based on waistline is feasible. The images obtained and the quality of the post-processing images can meet the needs of clinical diagnosis and can be applied to the examination of thoracolumbar trauma.
2019, 28(1): 121-127. doi: 10.15953/j.1004-4140.2019.28.01.13
Abstract(309) PDF(6)
Abstract:
Objective: To assess the value of multiple imaging signs on high-resolution CT in the differential diagnosis between benign and malignant solitary pulmonary nodules (SPN). Methods: 102 cases of SPN with surgery or pathologically confirmed from April 2016 to April 2018 were retrospectively analyses. The data's of multiple image signs on high-resolution CT for diagnosing benign and malignant lesions were collected, and the diagnosis accuracy of combined and single signs were compared. Results: The incidence of calcification in malignant lesions was 4.26%, which was lower than that of benign lesions. The incidences of lobulation signs, vascular bundle signs and burrs signs were 63.83%, 40.43% and 70.21% respectively in malignant lesions, all of these were higher than those of benign lesions. All of the differences mentioned above were statistically significant (P<0.05). No significant differences were shown in the incidence of satellite foci, vacuolar sign and pleural depression between benign and malignant lesions (P>0.05). The positive predictive value of combined signs of vascular bundle signs, burr signs and lobulation signs was significantly higher than that of single sign (P<0.05). Conclusion: High-resolution CT signs are of high value in the differential diagnosis of benign and malignant SPN, and combined multiple CT signs is higher accuracy than single CT sign.
2019, 28(1): 129-137. doi: 10.15953/j.1004-4140.2019.28.01.14
Abstract(269) PDF(6)
Abstract:
Objective: To investigate the clinical symptoms and MRI features of ovarian malignant germ cell tumors. Methods: Clinical data and MRI images of seven cases with ovarian malignant germ cell tumors confirmed by operation and pathology were retrospectively analyzed, including 1 case of dysgerminoma, 3 cases of yolk sac tumor, 2 cases of immature teratoma and 1 case of mixed germ cell tumor. Results: The clinical symptoms of 7 patients were 1 case of abdominal pain, 3 cases of abdominal mass and 3 cases of abdominal distension. Tumor markers levels: AFP was significantly increased in 6 cases; CA125 was elevated in 3 cases. MRI features: All the tumors were unilateral lesions, including 4 on the right side and 3 on the left side. There were 6 cases of quasi-circular shape and 1 case of lobular shape, the boundary is clear. The maximum diameter of all lesions is greater than 9cm. One case of dysgerminoma was mainly composed of solid components, while the other 6 cases were cystic. 1 case of dysgerminoma saw low signal separation, 2 cases of immature teratoma saw small cystic fluid signal area, and scattered fat signal. Enhanced scanning: 1 case of dysgerminoma was moderately enhanced, with continuous enhancement separation. In 6 cases, the solid part of cystic neoplasm was continuously strengthened, 3 cases of yolk sac tumor showed "honeycomb sign", and 2 cases of immature teratoma showed multiple cystic unenhanced areas. There were 5 cases with peritoneal effusion and 2 cases with yolk sac tumor with irregular thickening of the omentum. In one case, dysgerminoma was accompanied by pelvic and retroperitoneal lymph node enlargement, but no lymph node enlargement was observed in other cases. Conclusions: Combined with clinical manifestations, preoperative tumor marker detection and MRI features, it is helpful for the correct diagnosis and differential diagnosis of ovarian malignant germ cell tumors.
2019, 28(1): 139-146. doi: 10.15953/j.1004-4140.2019.28.01.15
Abstract(318) PDF(6)
Abstract:
Objective: Assessing the correlation between MCTSI score combined with D-dimer detection value and the clinical prognosis in patients with acute pancreatitis. Methods: 150 acute pancreatitis patients admitted to our hospital from August 2016 to January 2018 were collected. The plasma D-dimer detection value was recorded on the first day after admission. The CT enhancement scan was performed on the 5th to 7th day. According to the MCTSI standard, the combined detection value of MCTSI score and plasma D-dimer detection value was obtained by Logistic regression equation. MCTSI score, D-dimer detection value and combined detection value were analyzed by ROC curve. Results: There were significant differences in plasma D-dimer detection value and clinical prognosis among mild, moderate and severe acute pancreatitis patients (P<0.001). The D-dimer detection value in severe patients was significantly higher than that in mild and moderate patients (P<0.001). The combined detection value of MCTSI score and plasma D-dimer detection value obtained by Logistic regression equation is more effective in predicting organ failure than using MCTSI score and plasma D-dimer detection value alone, and it has the highest correlation coefficient with the length of hospital stay. MCTSI score combined with D-dimer detection value has high clinical reference value for clinical prognosis of acute pancreatitis patients. Conclusion: According to the combined evaluation of MCTSI and D-dimer detection value, we can understand the clinical prognosis of acute pancreatitis patients, which has a high clinical reference value.
2019, 28(1): 147-152. doi: 10.15953/j.1004-4140.2019.28.01.16
Abstract(404) PDF(10)
Abstract:
Objective: To summarize the MRI findings of ischiofemoral impingement syndrome (IFIS), promote the recognition of this disease. Materials and Methods: The MRI images of 84 hips with IFIS (case group) confirmed in our hospital and 116 normal hips (control group) were retrospectively analyzed. Ischiofemoral space (IFS), quadratus femoris space (QFS), distance between sciatic tuberosity were measured on the axial T1WI MR images, and the morphological and signal of the quadratus femoris muscle were observed on the axial PDWI-FS images. Results: Independent sample t-test analysis indicate the IFS and QFS ((2.36±0.47) cm, (1.58±0.39) cm) of control group were significantly higher than that of case group ((1.56±0.42) cm, (0.89±0.24) cm), and the distance between sciatic tuberosity of control group ((10.51±1.53) cm) was lower than that of case group ((11.39±1.01) cm), and the differences between the two groups were statistically significant (P<0.05). Pearson correlation analysis indicate there was a significant positive correlation between IFS and QFS, r=0.813, P<0.05; There was a negative correlation between distance between sciatic tuberosity and IFS, r=-0.263, P<0.05. In the IFIS patients, the quadratus femoris muscle showed different degrees of deformation and edema. In the whole data, the IFS and QFS in the young and middle-aged group ((2.09±0.55) cm, (1.32±0.47) cm) were all higher than that of the elderly group ((1.90±0.58) cm, (1.19±0.39) cm), P<0.05; and there was no significant difference in the distance between sciatic tuberosity between the two groups. Conclusion: The narrowing of IFS and QFS, and the deformation and edema of quadratus femoris, are the typical MRI findings of ischiofemoral impingement syndrome.