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 the therapeutic effect of endocrine for prostate cancer with bone metastases with MR diffusion-weighted imaging (DWI). Methods Forty patients with bone metastases from prostate cancer were examined with DWI. Seventeen patients underwent endocrine therapy were recruited as the test group, the other 23 were regarded as the control group. There was no relapse of the metastases according to clinical diagnosis in the test group. DWI sequences were based on steady-state free precession with b value (800 s/mm~2). After identifying the metastasis according to the T1WI and T2WI, ROIs were marked at the metastases, normal muscle, normal bone and bladder on DWI, and the ADC values of the ROIs were calculated respectively. Non-parameter two independent samples test was applicated to compare the ADC values of the metastases between the two groups.Results ADC values of the bone metastases were (1.10±0.50)×10~(-3)mm~2/s in the test group and (1.12±0.30) ×10~-3mm~2/s in the control group (P>0.05).Conclusion MR DWI shows no help in evaluating the therapeutic effect of endocrine for prostate cancer with bone metastases.

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 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.

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 compare pediatric patients with periventricular leukomalacia (PVL) with normal children by using diffusion tensor MR imaging. Methods Diffusion tensor images were obtained in 15 pediatric patients with PVL and 15 age-matched normal children. Regions of interest were drawn to measure the fractional anisotropy (FA) in bilateral posterior limb of internal capsule, bilateral optic radiation, genu of corpus callosum, and splenium of corpus callosum. The values of PVL patients and normal children were compared using non-dependent samples T-test. Results The FA values of regions of interest prescribed were significantly lower in PVL patients than in normal children(P

Objective To investigate the clinical value of tumor's longest diameter and volume in assessing pathologic response in locally advanced breast cancer treated with neoadjuvant chemotherapy(NAC).Methods A prospective study was undertaken in women undergoing NAC for locally advanced breast cancer in order to determine the ability of quantitative MRI to assess the final pathologic response. 36 cases with pathologically confirmed locally advanced breast cancer who had been undergone four courses of NAC underwent preoperative breast MRI three times during the NAC. Pathologic response was assessed according Miller & Payne grading system, of which grade 4 and 5 defined as major histological response (MHR), and grade 1 to 3 as non-major histological response (NMHR). The tumor's longest diameters and volumes in MHR were compared with those in NMHR by Mann-Whitney U test before, after the second and fourth cycle of NAC. Concordance correlation coefficient (CCC) were assessed to evaluate the agreement between the two method. Receiver operating characteristic curve (ROC) analysis was carried out to assess the clinical value of tumor size and the change rate.Results Before,after the second and the fourth cycle of NAC, the difference of tumor's longest diameters and their first change rate between MHR [(2.75±1.16) cm,(2.19±1.07) cm ,(1.58±0.75) cm and (21.70±15.09)%]respectively,and NMHR [(2.71±1.10) cm,(2.33±0.90) cm,(2.01±0.94) cm and (11.68±10.27)%] respectively were not significant(P>0.05). The second change rate of tumor's longest diameter in MHR [(39.00±15.38)% ] was significantly higher than that in NMHR[ (25.83±21.77)% ](P=0.04). Before, after the second and the fourth cycly of NAC, the differences of tumor volumes and their first change rate between MHR [ median 14.00 cm~3 ( range 2.96～83.41 cm~3 ) , median 7.31 cm~3 (range 0.05～55.35 cm~3), median 2.69 cm~3 (range 0～33.40 cm~3 ) , median 48.65% (range 33.64%～98.48%) ] and NMHR [median 4.25 cm~3 (range 4.78～106.55 cm~3), median 10.53 cm~3 (range 1.72～42.85 cm~3), median 7.56 cm~3 (range 0.68～156.58 cm~3), median 52.04% (range-35.79%～78.31%) ] were not significant. The second changing rate of tumor's volume in MHR [median 85.37% (ranged 27.52%～100%)] was significantly higher than that in NMHR [median 68.80% (ranged -289.60%～94.24%)](P=0.01). CCC was computed before and (0.82), after the second cycle (0.67) and after the fourth cycle (0.55), in all examinations pooled together (0.78).The second change rates of tumor's longest diameter and volume were equal to predict the final pathologic response, and the area under curve were 0.75 and 0.80, respectively (P=0.61). Conclusion The agreement between the tumor's longest diameters and tumor's volumes is good in all in breast carcinoma. The assessment efficacy of the change rate of tumor's longest diameter and that of volume were low.