[en] Objective: To discuss the diagnostic value of multi-slice computed tomography(MSCT) as an imaging technique used for upper vein angiography. Methods: A total of 56 cases were referred for upper limb vein check by MSCT from June 2010 to March 2012. The veins were scanned by using the LightSpeed 16 computed tomography(CT) scanner and reconstructed by using volume rendering, maximum intensity projection, multi-planner formation, and curve planner reformation. Three different layers were selected to measure the CT value of A, B, and C(i.e., the axial image of the cephalic and brachial veins between condyles of the humerus at 5 and 8 cm and the axial image of the subclavian vein). Statistical analysis was conducted by using SPSS 17.0, whereas one-way ANOVA F test was used to analyze the measured CT value(P < 0.05 was considered statistically significant). Results: Out of 56 patients, 14 cases of right upper limb and 21 cases of left upper limb were detected to have deep vein thrombosis. That is, 62.5%(35/56) of the cases were detected by MSCT as compared with 58.9%(33/56) of the cases detected by color Doppler. The CT value of the axial image of the brachial and cephalic veins between condyles of the humerus approximately 5 and 8 cm near the heart was P > 0.05, whereas that of the axial image of the subclavian vein was P > 0.05(F = 0.001). In different layers of vein filled with contrast medium, the CT values were uniform and the differences of the values exhibited no statistical significance between different layers. The contrast medium concentration in the distal part of the upper limb vein was higher than that near the heart, and the differences of the CT values exhibited statistical significance between different layers(F = 1441.52, P < 0.05). Conclusions: In conclusion, the MSCT is a superior technology for upper limb vein imaging because it is able to show the upper limb in an extensive range, display the collateral circulation clearly, identify the causes of hemadostenosis, and predict the occurrence of thrombogenesis. Simultaneously, this technology significantly reduces the dosage of iodine contrast agent, lowers the economic burden of patients, improves the rate of correct diagnosis for lesions, and provides reliable bases for selecting correct methods of treatment in clinics. (authors)

[en] Objective: To explore the feasibility and application value of kV Assist technology in reducing radiation dose for lumbar CT examination. Methods: Sixty patients with suspected of lumbar disease and requiring lumbar CT examination were prospectively enrolled in the study (55 males, 5 females, age 38.2 ± 2.7 years, BMI 21.8 ± 1.1 kg/m²). The patients were randomly separated into two groups: group A (n = 30) scanned using conventional mode (120 kV and 230 mA), and group B (n = 30) scanned using kV assist. The volumetric CT dose index volume (CTDI_vol), dose-length product (DLP), and effective dose (ED) were recorded. Subjective image quality was evaluated by a 5-grade scale. The contrast noise ratio (CNR) and signal to noise ratio (SNR) in the bone and soft tissue windows were calculated. The age, BMI, CTDI_vol, DLP, ED, SNR, and CNR were compared with independent samples-t test, and the subjective image quality was compared with Wilcoxon rank sum test between the two groups. Results: The group B had significant lower (over 45%) CTDI_vol, DLP, and ED than the group A (all P < 0.05). In the bone window, The group B had significantly higher CNR, SNR, and subjective image quality than the group A (all P < 0.05). However, there were no statistically significant differences in CNR, SNR, and subjective image quality between group A and group B in the soft tissue window (P > 0.05). Conclusion: In lumber CT examination, application of kV Assist technique can reduce radiation dose and improve image quality. (authors)

[en] Objective: To study the CT features of nasal bone foramen and nasal bone fracture, and investigate the differential key points of them. Methods: visual observation was performed for 30 selected skull specimens of adults (60 nasal bones) (specimens group), then CT imaging was obtained for them with volume redering (VR) reconstruction (imaging group). The frequency of the nasal bone foramens, their size, shape and location were statistical analysed. Ferthermore, CT features of nasal bone foramen and nasal bone fracture were analyzed in 30 patients who were suspected having nasal bone fractures by clinicians. Results: Forty foramen shape nasal bone foramens were found in observation group, while 37 were obtained in imaging group. For patients, 19 cases were diagnosed as single fracture of nasal bone by non-spiral axial high-resolution CT images. When using both axial and multi-plane reformation (MPR) and VR images, 8 of 19 cases were diagnosed as single fracture, 5 were multiple fractures, 4 were normal nasal bone foramen, and 2 were normal variation. The other 11 cases that were diagnosed as multiple fractures by non-spiral axial HRCT images were demonstrated as 6 cases multiple fractures and 5 single fracture by combining axial images with MPR and VR images. The frequencies of foramen shape nasal bone foramen in specimens group and imaging group were 66.7% and 61.7%, respectively, and there were no significant differences between them (χ²=1.33, P>0.05). Conclusion: The nasal bone foramen is the normal anatomy, and to recognize the imaging findings of it can improve the diagnostic accuracy of nasal bone fracture. (authors)

[en] Objective: To analyze the relative position changes of C4 and C5 in normal volunteers during the flexion to extension motion of cervical spine on dynamic radiography. Methods: 22 volunteers without cervical spondylosis symptoms and radiographic signs underwent dynamic radiography. They were divided into the low-risk (13 subjects < 40 years of age) and high-risk (9 subjects ≥ 40 years) groups. The flexion to extension motion was divided into 20 equal parts according to time. The intersection of anterior and inferior edges of C6 was used for all dynamic image registration. The angles formed by intersection of anterior and superior edges of C4 and C5 vertebral bodies were calculated on Matlab. Statistical analysis was performed using repeated measurement ANOVA. Results: During flexion to extension motion, the relative positions of C4 and C5 were correlated (P < 0.001) and the relative position changes were significantly different (F = 16.185, P < 0.001). The difference of average relative angles of C4/5 between low risk and high risk groups was statistically significant (F = 6.573, P = 0.019). A seven-degree equation was the best curve fit (P = 0.934). Conclusion: The C4 and C5 flexion-to-extension position change of healthy adults has a regular pattern that can be described by a seven-degree equation. The position change is reduced in adults older than 40 years of age. (authors)