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.

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 compare the diagnostic value of MRS acquired by body coil(BODY)and endorectal Coil(ERC)in the detection of prostate cancer.Methods MRI and 3D MRS were performed in 12 patients with prostate disease,in which 6 of them were proved to have prostate cancer and the other 6 noncancerous disease.Both BODY and ERC MRS were performed in 7 patients,and only BODY MRS was performed in the other 5 patients.All MRS data were quantitatively assessed with a per-sextant method.The metabolic ratio of(Choline+Creatine)/Citrate[(Cho+Cre)/Cit]was measured in each ROI.ROC analysis was carried out to assess and to compare the diagnostic value of BODY and ERC MRS in patients with prostate cancer with Wilcoxon test.Results (1)The ratios of(Cho+Cre)/Cit in the prostate cancer group(median 1.744,0.295 to 7.998)was statistically higher than that in the non-prostate cancer group (median 0.412,0.112 to 2.113)acquired by using BODY MRS(Z=-9.159,P＜0.01).(2)The ratios of(Cho+Cre)/Cit in the prostate cancer group(median 1.975,0.479 to 7.998)was statistically higher than that in the lion-prostate cancer group(median 0.400,0.104 to 2.232)acquired by using ERC MRS(Z=-9.200,P＜0.01).(3)The mean ratios of(Cho+Cre)/Cit in the prostate cancer group and in the non-prostate cancer group acquired by using both coils were not of statistically significant difference(P＞0.05).(4)ROC analysis for diagnosing prostate cancer showed no significant difference(P=0.851)between the areas under the curve of BODY and that of ERC MRS(Az=0.93 1 and 0.935 respectively).Conclusion The BODY MRS could provide comparable diagnostic efficacy to ERC MRS in patients with prostate cancer.

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.

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 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 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.

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.