Objective To investigate the optimal beam tube potential for amorphous silicon/cesium iodide flat panel digital chest radiography(indirect DR). Methods(1)60 healthy adults were undergone digital posteroanterior(PA) chest radiography at 80,100,150 kV respectively.The images quality of these three were compared by 5 independent observers.Several normal anatomy parts of the chest and the overall impression of the images were evaluated;(2)PA chest exposures of the anthropomorphic chest phantom to produce a constant ESDs(entrance skin doses) and exit dose were made using tube potential at 80,100,120,150 kV.The simulated chest nodules were scored. Results The quality of the adult chest radiography and the manifestation of the simulated chest nodules were superior at the lower tube voltages.The contrast of the images were best at 80 kV,while the appearance of the images look like that of the low potential radiography. Conclusion The optimal tube potential for chest DR is considered to be 80~100 kVp,while the high KV technique is no longer suitable for digital equipment.

ObjectiveStudy the ADC value and the maximal diameter and their changes of breast cancer before and after neoadjuvant chemotherapy,to determine the relationship with different expression level of Ki-67.Methods Forty eight patients with breast cancer confirmed by biopsy underwent MR DWI and enhanced scan before and after 4 cyclesneoadjuvant chemotherapy.ReviewtheMRimages retrospectively.The ADC value and the maximum diameter( D)of the cancer foci were measured before and after chemotherapy,and the rate of their changes △ADC％ and △D％ were calculated.Using different Ki-67 index level,all the foci were divided into three groups:group A with Ki-67 ＜ 20％,group B with Ki-67 between 20％ and 60％,and group C with Ki-67 ＞ 60％.Using nonparameter test to compare the ADC values,△ADC％,D and △D％ of the three groups before and after chemotherapy,determine whether there were differences.ResultsBefore chemotherapy,the ADC value of group A ( n = 15 ) was 1.1 ×10-3 mm2/s[ (0.9 × 10-3—1.2 × 10-3) mm2/s],which was higher than that of group B[n = 8,0.9 ×10-3 mm2/s(0.9 × 10-3-1.0 × 10-3) mm2/s] and C [n =25,0.9 × 10-3 mm2/s(0.7 × 10-3—1.2 ×10-3) mm2/s],and the difference was statistically significant (P ＜0.05 ) ; while the ADC value of group C after chemotherapy was 1.3 × 10 -3 mm2/s[ (0.2 × 10 -3—1.4 × 10 -3 ) mm2/s],which was higher than that of group A [1.1 × 10-3 mm2/s,(1.0 × 10-3—1.2 × 10-3) mm2/s] and B[1.1 × 10-3 mm2/s,( 1.0 × 10-3-1.1 × 10 -3 ) mm2/s],and the differences were statistically significance ( P ＜ 0.01 ) ; the ADC change rate( △ADC％ ) of group C was 45.5％ ( - 12.0％ —78.6％ ),which was greater than group A [45.5％ ( - 12.0％—78.6％ ) ] and B [ 45.5％ ( - 12.0％—78.6％ ) ],the difference was significant (P ＜ 0.01 ).The maximum diameters of group A were 2.2 cm (2.0—2.4 cm)and 1.0 cm(0.0—1.4 cm)before and after chemotherapy,lower than those of group B [ 3.7 cm ( 3.6—3.9 cm ) before NAC,2.9 cm (0.0-3.1 em) after NAC] and group C[3.4 cm(2.7—4.2 cm) before NAC,1.9 cm(0.0—2.2 cm) after NAC ],and the differences were statistically significant ( P ＜ 0.05 ) ; the change rate of the maximum diameter in group B was 21.6％ ( - 15.2％—27.5％ ),which was less than group A [52.7％ ( -23.6％—72.1％)] (P＜0.01) and C [51.2％ ( -10.3％—92.6％)] (P ＜0.05),and the difference was statistically significant.Conclusion The ADC values and the maximal diameter of breast cancer differed with different expression levels of Ki-67 index before and after neoadjuvant chemotherapy,and the response to neoadjuvant chemotherapy of which varied as well.

Objective To study the value of the semiquantitative-parameter analysis of wash out index of time-intensity curve (Swash-out) in evaluating the therapeutic effect of neoadjuvant chemotherapy for locally advanced breast cancer (LABC).Methods Fifty-nine women with LABC underwent dynamic contrast enhancedt MRI examination before chemotherapy,after the 2nd cycle and the 4th cycle of chemotherapy.All patients were divided into major histological response group (MHR) and non-major histological response group (NMHR) according to the final pathologic response.Swash-out and the variancetrends of Swash-out before NAC,after the 2nd cycle of NAC and after the 4th cycle of NAC were compared in each group and between the two groups.According to the gold standard of Miller & Payne criterion,Receiver operating characteristic curve (ROC) analysis was performed to evaluate the predicting effect of Swash-out for NAC response,and to compare it with Semi-quantitative TIC curve indicators Smax (steepest slope) and PPE (peak percent enhancement).Results Fifty-nine patients of LABC patients were divided into a MHR group of 34 patients and a NMHR group of 25 patients.Swash before NAC of MHR group was-16.99 (-56.72-41.20),Swash-out after the 2nd cycle of NAC was 5.66(-69.45-53.08),Swash-out after 4th cycle of NAC was 15.95 (-7.80-54.23).Swash-out before NAC of NMHR group was-23.08 (-64.24-34.39),Swash-out after the 2nd cycle of NAC of NMHR group was-23.01 (-52.72-28.70),Swash-out after 4th cycle of NAC of NMHR group was-11.45 (-50.49-50.93).Swash-out variance rate of MHR group after the 2nd and the 4th cycle of NAC were-1.18 (-31.32-60.86) and 1.50 (-86.27-3.61),respectively.Swash-out variance rate of NMHR group after the 2nd and the 4th cycle of NAC were-0.28(-3.24-9.46) and 0.27 (-5.34-3.11),respectively.Swash-out was not significantly different between the two groups before NAC (Z =-0.97,P ＞0.05).Swash-out and Swash-out variance rate of MHR group after the 2nd cycle of NAC were significant higher than that of NMHR group (Z =-3.97 and-3.02,P ＜0.01).Swash-out and Swash-out variance rate of MHR group after the 4th cycle of NAC were significant higher than that of NMHR group (Z =-3.96 and-3.16,P ＜ 0.01).Area under curve (Az) after the 2nd and the 4th cycle of NAC were 0.805 and 0.804,respectively,and no significant difference was found between them (Z =0.019,P ＞0.05).Diagnostic cut-off points were-8.670 for the 2nd cycle of NAC and 4.105 for the 4th cycle of NAC.Diagnostic sensitivity was 79.42％,specificity was 76.00％ and Youden index was 0.554,for after the 2nd and the 4th cycle of NAC.Conclusion Swash-out of TIC curve before NAC cannot predict the response of NAC,Swash-out of TIC curve after the 2nd cycle of NAC and after the 4th cycle of NAC are efficient in predicting the response of NAC.

Objective To evaluate and testify the diagnostic efficacy of the ADC value of the diffusion-weighted imaging (DWI) in prostatic peripheral zone cancer. Methods There were 40 patients with prostatic diseases proved by ultrasound guided systemic biopsy. DWI scans were performed with 1.5T MR scanner using TOSORPA coil and b value of 800 s/mm2. The peripheral zones of prostate were divided in six areas and were attributed to noncancerous and cancerous areas according to the results of biopsy. The minimal ADC values of each peripheral zone were recorded and analyzed. Results There were 240 areas, in which 89 areas were cancerous and the others were noncancerous. The mean ADC value of cancerous areas was (0.98±0.30)×10-3 mm2/s, while the noncancerous areas was (1.59±0.29)×10-3 mm2/s. The diagnostic sensitivity, specificity and accuracy were 80.58%, 92.42% and 86.73% respectively with cutoff point ≤1.24×10-3 mm2/s, whereas 66.56%, 96.95% and 86.26% respectively with cutoff point ≤1.04×10-3 mm2/s. The diagnostic sensitivity was 98.63%, the specificity was 37.07%, the accuracy was 58.82% with cutoff point <1.69×10-3 mm2/s. Conclusion The ADC value ≤1.24×10-3 mm2/s should be regarded as the diagnostic standard of prostate cancer. When ADC value is between (1.04-1.24)×10-3 mm2/s, some cancer might be missed.

Objective To evaluate the diagnostic efficacy of MRS in prostate cancer based on sextant localization. Methods There were 110 patients, 54 patients with pathologically confirmed prostate cancer and 56 patients confirmed non-prostate cancer proved by ultrasound guided systemic biopsy. The (choline + creatine)/citrate (CC/C) value in each voxel and ratio of positive voxel (PVR) in sextant localization were measured. The ROC analysis was used to evaluate the diagnostic efficacy of CC/C in single voxel and PVR in sextant localization. Results There are 1673 and 2426 voxel in prostate cancer and non-prostate cancer respectively. The median of CC/C in cancer sextants was 2. 137; the median of CC/C in noncancer sextants was 0. 600. The difference of these two groups was statistically significant (Z = -41.7, P < 0. 01 ). The diagnostic sensitivity was 81.4% ( 1362/1673 ), the specificity was 83.1% (2018/2426), and the accuracy was 82.4% [ (1362+2018)/4099] for prostatic cancer with the cutoff point 0. 911 of the CC/C value. The median of PVR in cancer sextants and noncancer sextants were 1 and 0 respectively, the difference of PVR was statistically significant (Z = -11.7,P < 0.01 ). The diagnostic sensitivity was 77. 5% (148/191), the specificity was 76. 9% (247/321), and the accuracy was 77. 1% [ ( 148 + 247 )/ 512] for prostatic cancer with the cutoff point 0. 519 of the PVR. Conclusion Detecting the cutoff point of the CC/C value in single voxel and the PVR in sextant localization may be valuable in the diagnosis of prostate cancer.

Objective To quantitatively analyze and testify the diagnostic value of combined MRS and DWI for prostate cancer based on sextant localization.Methods Patients who underwent prostate MR examinations in our hospital had MRS and DWI scanning in addition to conventional MRI.The(choline+creatine)/citrate(CC/C)value in each measurable voxel and the minimal ADC value(ADC_(mini))in each sextant were measured.Taking CC/C of no less than 0.911 as the cutoff value for prostate cancer,the ratios of positive voxel(PVR)in sextants were calculated.The selected patients were divided into 2 groups according to the date of examination,for the quantitative analysis and the verification respectively.Group 1 was from Feb,2006 to Dec,2006,and group 2 from Jan,2007 to Jul,2007.The diagnostic efficacy of PVR,ADC_(mini) and their combination was tested by ROC analysis.Results There were 40 patients in group 1 and group 2 respectively for the linear discrimination of the cluster analysis,including 20 patients with prostate cancer and 20 patients without prostate cancer.The linear discrimination equation calculated from group 1 was 'D=3.264×ADC_(mini)-0.205×PVR-4.407'.The areas under curve(Az)of ROC for PVR,ADC_(mini) and D were 0.769,0.910 and 0.909,respectively.In group 2,the Az of ROC for PVR,ADC_(mini) and D were 0.838,0.912 and 0.915,respectively.There were no statistical difference between ADC_(mini)-alone and D in both groups(X~2=0.32 and 1.50,P＞0.05).Conclusions Quantitative prostate DWI had higher diagnostic value than MRS.The combined use of MRS and DWI was not superior to the DWI-alone in the diagnostic efficacy of prostate cancer.

Objective To study the normal changes in brain during childhood by analyzing the diffusion characters of different regions and different age phases with diffusion tensor imaging (DTI). Methods DTI was performed in 63 children (age range, 2 days to 9 years) without brain abnormalities and the data measured in ADC maps were analyzed statistically. Results (1) There were significant differences in ADC values among some different regions of brain tissue; (2) In babyhood, the ADC values in gray matters decreased faster than in white matters; (3) The ADC values decreased with the increasing of age , and show negatively exponentially correlation with age. Conclusion DTI shows the changes of brain tissue composition in vivo, with which normal changes in brain during childhood can be evaluated.

Objective To study findings of the white matter of nomal children on color tensor map and evaluate the diffusion tensor imaging in the assessing development of the brain. Methods DTI was obtained in 89 normal children aging from 2 days to 18 years.Their color tensor maps were generated and analyzed.Results Their color tensor maps revealed different findings due to aging;with the increase of the age,the fiber tracts showed were more and well defined.Conclusion The color tensor map is superior to the routine MR in assessing the development of the white matter.

Objective To assess the difference in detection of simulated chest nodules in different lung fields with dual-energy digital subtraction chest radiography by receive operating characteristic curve (ROC) analysis.Methods Dual-energy digital subtraction chest radiography was performed on 20 volunteers with simulated chest nodules. ROC analysis was made in the evaluation results on regular DR images and soft tissue images in different lung fields respectively.Results Az was greater on the soft tissue images than on the regular DR images in the superior lung fields and outer zone of middle lung fields. There were significant differences in the superior lung fields and outer zone of middle lung fields.Conclusion Dual-energy digital subtraction chest radiography is superior to regular DR image on detecting more chest nodule lesions, especially in the superior lung fields and outer zone of middle lung fields. So the two techniques should be united to diagnose.

Objective To analyze MRI characteristic features of TSC.Methods 13 clinically proven patients with TSC,each one had head MR scanning.Results There were mainly four findings on MRI:①Subependymal nodules,which were detected in all cases.Of them 71 lesions on T 1WI,39 lesions on T 2WI and 56 lesions on PDWI were detected;②Cortical tubers in 11 cases,114 lesions on T 2WI and PDWI,72 lesions on T 1WI were detected;③The abnormal findings of white matter,which were detected in 5 cases,10 lesions on T 2WI and PDWI,none on T 1WI were detected;④Subependymal giant cell astrocytoma,only 1 case detected.Conclusion MRI is sensitive to the changes in central neural system in TSC and is the first choice among the diagnostic imaging modalities.T 1WI is sensitive to the subependymal nodules,while T 2WI and PDWI were sensitive to the cortical tubers and abnormal findings of white matter.