Correlation between gestational age and ADC value in normal fetal brain region detected using DWI with b value as 1 000 s/mm2 / 中国医学影像技术

Objective: To investigate the relationship between ADC value of normal fetal brain region obtained on ADC image generated with DWI of b value as 1000 s/mm2 and gestational age. Methods: A retrospective analysis of 106 pregnant women who underwent routine MR and DWI examinations due to suspected fetal abnormalities with prenatal ultrasonography was performed. Among them, 28 pregnant women were in the second trimester (13-27 weeks) and 78 pregnant women were in the third trimester (≥28 weeks). All fetuses were confirmed as normal neurodevelopment with prenatal routine MR and DWI examinations, as while as postnatal follow-up. DWI was performed with b value of 1000 s/mm2. ADC maps were generated based on DWI,and ADC values of frontal lobe, parietal lobe, temporal lobe, occipital lobe white matters, basal nucleus, thalamus, cerebellar hemisphere and pons were measured. The correlation between ADC values in different fetal brain regions and gestational age was analyzed using linear regression. Results: ADC values of different parts of normal fetal brain were in order from high to low: Parietal white matter ([1.84±0.08]mm2/s), occipital white matter ([1.82±0.08]mm2/s), frontal white matter ([1.77±0.03]mm2/s), temporal white matter ([1.70±0.13]mm2/s), cerebellar hemisphere ([1.41±0.10]mm2/s), basal ganglia ([1.40±0.13]mm2/s), thalamus ([1.35±0.04]mm2/s), pons ([1.27±0.08]mm2/s). Except for frontal white matter, ADC values of the rest of the normal fetal brain regions were negatively correlated with gestational age (all P<0.05). Conclusion: Most of ADC values in normal fetal brain different regions decreased with increasing gestational age, which can reflect the developmental process of fetal brain.

Research on the effect of nanofat combined with granular fat injection in the treatment of mixed dark circle at lower eyelid / 中华整形外科杂志

Objective@#To investigate the clinical effect of subcutaneous injection of nanofat combined with autologous fat into tear trough deformity to improve the mixed dark circle at lower eyelid, and the feasibility of using L*a*b* value to objectively evaluate the improvement of skin color at the lower eyelid with dark circle.@*Methods@#A total of 14 patients with the mixed dark circle at lower eyelid, admitted by Union Hospital of Tongji Medical College of Huazhong University of Science and Technology from November 2017 to August 2018 were selected. They were all female, aged between 21 and 46 years old. Thigh or abdomen was selected as the fat donor area. Autologous fat was filled into the tear trough deformity. The prepared nanofat was injected into the subcutaneous layer of the lower eyelid with dark circle. Photoes were taken under the same condition and same room temperature for patients before operation and 6 months after operation. Photoshop, CS7 exposure correction, as well as 64 Image J software measurement were adopted to evaluate the skin L* a* b* value at dark circle of lower eyelid. SPSS 20.0 rows of data statistical analysis was applied with paired t test(P<0.05).@*Results@#All patients were followed up for 6 months after the operation, and a satisfactory effect was achieved after one injection, with an overall satisfaction rate of 78.6% (11/14). The color and skin fine wrinkles at the dark circle of the lower eyelid were improved in 14 patients, and the contour of the injection area was smooth without obvious complications. 6 months after the operation, the L* value of the skin at the lower eyelid with dark circle was 55.13±5.56, which was 7.74±2.39 higher than the preoperative value of 48.23±5.63, showing significant difference(t=12.089, P=0.00). Six months after surgery, the a* value was 14.68±2.84, which decreased by 0.11±0.60 compared with 14.79±3.04 before surgery, showing no statistically difference(t=-0.71, P=0.49). Six months after surgery, the b* value was 19.77±3.45, which increased by 0.27±1.03 compared with 19.50±3.45 before surgery, showing no statistical difference (t=0.98, P=0.35).@*Conclusions@#Subcutaneous injection of nanofat combined with autologous fat injection for tear trough deformity is effective in the treatment of lower eyelid with mixed dark circle. The L*a*b* value can objectively evaluate the improvement of skin color at the lower eyelid with dark circle.

Diagnostic value of b value threshold maps based on diffusion weighted imaging images for pancreatic cancer / 中华胰腺病杂志

Objective To investigate the feasibility of b value threshold maps based on MRI diffusion weighted imaging ( DWI ) in the diagnosis of pancreatic adenocarcinoma .Methods The preoperative MRI DWI [ b value=0( b0 ) and 1000 ( b1000 ) s/mm2 ] data of 14 patients who were postoperatively histologically confirmed as pancreatic ductal adenocarcinoma from September 2016 to May 2015 admitted in Shanghai Changhai Hospital were retrospectively analyzed .The b value threshold maps were calculated .Computed DWI images at b value of 1500 s/mm2 ( cDWIb1500 ) was calculated based on the scanned DWI images of b 0 and b1000 s/mm2 . The efficacy of DWIb 1000 , b value threshold map and cDWIb 1500 in manifesting pancreatic adenocarcinoma was assessed by a four-point scale .The non-parametric Friedman test was used to compare the three methods , and Conover adjusted method was applied to compare any two of the three methods .Results The conspicuity score of DWIb 1000 , b value threshold map and cDWIb 1500 in showing pancreatic cancer was 2.9 ±0.8, 3.7 ±0.5 and 3.6 ±0.5, respectively, and the differences among the three methods were statistically significant (F=19.5, P value <0.001), but the differences on tumor conspicuity scores of b value threshold map and cDWIb 1500 were not statistically different .Conclusions The calculation of b value threshold map based on DWI images could show pancreatic cancer in high contrast quickly by adjusting window width and window level , and could achieve comparable performance as cDWIb 1500 .

Computed Diffusion-Weighted Imaging in Prostate Cancer: Basics, Advantages, Cautions, and Future Prospects

Computed diffusion-weighted MRI is a recently proposed post-processing technique that produces b-value images from diffusion-weighted imaging (DWI), acquired using at least two different b-values. This article presents an argument for computed DWI for prostate cancer by viewing four aspects of DWI: fundamentals, image quality and diagnostic performance, computing procedures, and future uses.

Radio technician operation specification of multi b value DWI technique applied to liver tumor detection / 医疗卫生装备

Objective To enhance the standardized operation of multi b value DWI technique when the radio technician detects liver tumors.Methods The operation specifications of multi b value DWI technique applied to liver benign tumors diagnosis were analyzed for MRI conventional examination,MR-DWI scan,MR-DWI image processing.Considerations were also taken on unified detection standard,supervision system,management mechanism and etc.Results Radio technician was improved in operation specification when used multi b value DWI technique to detect liver tumors. Conclusion Radio technician operation specification of multi b value DWI technique has to be strengthened to enhance the clinical efficacy.

Diagnostic value of magnetic resonance multimode functional imaging in small hepatocellular carcinoma / 新乡医学院学报

Objective To investigate the magnetic resonance multimodal function imaging characteristics of small hepa-tocellular carcinoma and evaluate its diagnostic value in small liver cancer. Methods Thirty-nine patients with small hepato-cellular carcinoma were selected in the First Affiliated Hospital of Xinxiang Medical University from January 2016 to January 2018. The magnetic resonance plain scan data,dynamic enhance data and diffusion imaging data of all patients were analyzed. Results Forty-five lesions were found by plain scan,and 48 lesions(37 lesions were rapid rise and rapid descent type,6 le-sions were flatbed type,3 lesions were slow ascent and rapid descent type,2 lesions were not obvious strengthening type)were found by dynamic enhancement. The lesions were hyperintense or slightly hyperintense on the diffusion weighted imaging (DWI)image. The lesions were hyperintense or slightly hyperintense on the DWI. The main shape of lesions was round,irregu-lar ring and nodositas. The apparent diffusion coefficient(ADC)value of cancer tissue and normal liver tissue gradually de-creased with the increase of b value. Under the same b value,the ADC values of small hepatocellular carcinoma was significant-ly lower than that in the normal liver tissue(P < 0. 05). Conclusion Magnetic resonance multimodality functional imaging (magnetic resonance imaging dynamic enhanced combine with multi-b value DWI)can effectively improve the diagnostic effi-cacy of small hepatocellular carcinoma.

Diagnostic value of 3.0T MR multi high-b-value DWI in prostate cancer and its correlation with Gleason classification / 实用放射学杂志

Objective To investigate the diagnostic value of 3.0T MR high field high-b-value diffusion weighted imaging (DWI) in prostate cancer (PCa) and to analyze its correlation with Gleason classification.Methods A total of 78 cases proved by operation and pathology were collected,including 41 cases of benign prostatic hyperplasia(BPH) and 37 cases of PCa.PCa patients were classified according to postoperative pathological scores,and their correlation with ADC values was analyzed subsequently.Parameter scanning was performed in all patients by using Philps 3.0T MR with b value at 0 s/mm2,1 000 s/mm2 and 1 500 s/mm2.The signal intensity and ADC value of PCa and BPH were compared under two kinds of high-b-values,and the correlation between ADC value and Gleason classification was analyzed.Results It was found that the specificity and accuracy of T2WI combined with b value of 1 500 s/mm2 were higher than these of T2WI combined with b value of 1 000 s/mm2 for the diagnosis of PCa.The ranking result of ADC value corresponding to Gleason score of PCa after operation was:2-4 points ＞ 5-6 points ＞7 points ＞ 8-10 points.Besides,the ADC value of the corresponding lesion with b value of 1 500 s/mm2 was lower than that with b value of 1 000 s/mm2,and the difference was statistically significant (P＜0.05).Conclusion High field high-b-value DWI combined with T2WI is of high value in differential diagnosis of PCa and BPH,and the specificity and accuracy of PCa and BPH improve obviously with the increase of the b value.Additionally,the ADC value is negatively correlated with the Gleason score.

Diagnostic value of ultra-high b-value diffusion-weighted imaging in prostate cancer / 肿瘤研究与临床

Objective To explore the value of ultra-high b-value diffusion-weighted imaging(DWI) in diagnosis of prostate cancer. Methods According to inclusion and exclusion criteria, 73 consecutive examinees in Chinese PLA General Hospital from June 2014 to May 2015 were screened. Written informed consent was obtained from all patients. T2WI, conventional DWI with b-value of 1 000 s/mm2and ultra-high b-value DWI with 2 000 s/mm2and 3 000 s/mm2were performed in each examinee. Images were interpreted and were corresponding to histological results conducted by ultrasound guided prostate systematic biopsy. Reference biopsy as the gold standard,the sensitivity,specificity, positive predictive value(PPV) and negative predictive value (NPV) were calculated for each image. Sensitivity and specificity differences between ultra-high b-value DWI and conventional DWI were analyzed. The areas under the curves (AUCs) between ultra-high b-value DWI and other modalities were compared. Results The sensitivity and specificity for ultra-high b-value DWI were 92.5 % and 68.8 % with b-value of 3 000 s/mm2, and they were 88.1 % and 53.1 % for 2 000 s/mm2in peripheral zone. The sensitivity and specificity for ultra-high b-value DWI were 88.0 % and 88.2 % with a b-value of 3 000 s/mm2, and they were 80.0 % and 52.9 % for 2 000 s/mm2in transition zone. The values of sensitivity for ultra-high b-value DWI were significantly higher than those for conventional DWI both in peripheral zone and transition zone (all P <0.000 1). The detection of lesions was comparable with ultra-high b-value DWI at 2 000 s/mm2and 3 000 s/mm2in peripheral zone (P >0.05), whereas the value of specificity for 3 000 s/mm2were significantly higher than that for 2 000 s/mm2in transition zone (P<0.000 1). PPV and NPV for 3 000 s/mm2were significantly higher than those for the other three modalities both in peripheral zone(86.1 % and 81.5 %) and transition zone (91.7 % and 83.3 %). In peripheral zone, the AUCs were 0.591, 0.553, 0.698 and 0.806 in T2WI, conventional DWI and ultra-high b-value DWI at 2 000 s/mm2 and 3 000 s/mm2respectively, for the diagnosis of transition zone cancer were 0.693, 0.506, 0.665 and 0.881 respectively, and the AUCs for the ultra-high b-value with 3 000 s/mm2were the largest. Conclusion Ultra-high b-value DWI is an accurate and reliable method in the diagnosis of prostate cancer.

Application value of magnetic resonance DWI high b-value and ADC value in hyperacute cerebral ischemia / 重庆医学

Objective To investigate the value of DWI high b value and ADC value in the diagnosis of hyperacute cerebral is-chemia.Methods Adult SD rats were selected and divided into the control and ischemic group by adopting the random number table method,the ischemic group was re-divided into 0.25,0.50,2.00,4.00、6.00 h groups according to the ischemic time,6 cases in each group with a total of 42 cases.The ischemic group conducted the right middle cerebral artery occlusion(MCAO)for performing the head T2WI and DWI scanning(b values were 0,400,800,2 000,3 000 s/mm2),the CNR and SNR values were recorded,rs-T2WI, rs-DWI and relative apparent diffusion coefficient(rADC)were measured.Then the imaging change of ischemic area was observed. The sensitivity and specificity were detected.Results In b=2 000 s/mm2and 3 000 s/mm2,the diagnostic rates of DWI for hyper-acute cerebral ischemia were obviously higher than those in b=400 s/mm2and 800 s/mm2,and when the b values were 400,800, 2 000,3 000 s/mm2,the sensitivities were 16.7%,50.0%,100.0% and 100.0% respectively and the specificities were 16.7%, 50.0%,100.0% and 100.0% respectively.The difference of ADC values under different b values had statistical significance(P<0.05).Conclusion High b value DWI in the diagnosis of hyperacute ischemia is significantly better than that of low b value,espe-cially in the aspect of displaying the lesion at 0.25,0.50 h cerebral ischemia.

Usefulness of different-b-value diffusion-weighted imaging in early cerebral infarction / 医疗卫生装备

Objective To investigate the usefulness of different-b-value diffusion weighted imaging (DWI) in patients with early cerebral infarction and obtain the optimal b value of early cerebral infarction.Methods DWI at b-value of 1,000,2,000,and 3,000 s/mm2 was performed for 40 patients within 72 h after the onset of stroke using a GE Signa HDx 3.0T MRI scanner.Post-processing was done by the DWI specific software Function Tool to gain signal intensity and mean apparent diffusion coefficient in the lesions center and the contralateral normal brain tissue,respectively.The sensitivity of conventional MRI and different-b-value DWI was calculated in the diagnosis of early cerebral infarction.Results In 40 patients with early cerebral infarction,the sensitivity of b-values of 1,000,2,000,and 3,000 s/mm2 (DWIb=1 000,DWIb=2 000,DWIb=3 000) and conventional MRI in the diagnosis of early cerebral infarction were 100％,97.5％,97.5％,72.5％,respectively.With b value increased,signal intensity and ADC value declined.Under the condition of different b values,signal intensity and ADC value were statistically significant in region of interest (P＜0.05).Conclusion DWI is superior to conventional MRI scan in monitoring early cerebral infarction.With the increase of b value,the sensitivity is the higher to hyperacute cerebral infarction,the signal contrast is obvious,while signal to noise ratio of the image reduces.It is suggested that brain tissue contrast and the sensitivity to the new cerebral infarction is more predictable on b value =1,000 DWI than on the other DWIs.

Correlation research of multi-b value DWI combined with PSA on the effect of endocrinotherapy for prostate cancer / 实用放射学杂志

Objective To investigate the value of multi-b value DWI combined with PSA evaluation on the effect of endocrinotherapy for prostate cancer (PCa), and to study the correlation between the signal intensity(SI), apparent diffusion coefficient(ADC) with PSA.Methods Forty patients with PCa diagnosed by pathology or biopsy were tested for serum PSA levels before and after endocrine therapy.All patients underwent DWI at b-value of 300,800 and 1 000 s/mm2 by using a GE Signa HDx 3.0T MRI scanner.The serum PSA,the value of SI and ADC at different b values before and after endocrine therapy,and their correlation with PSA were observed and measured, respectively.Results (1)The serum PSA before and after endocrine therapy were (35.63±20.91) ng/mL and (5.98±3.84) ng/mL, respectively.The difference was statistically significant (P0.05).(3)Pearsoncorrelation analysis showed that ADC value was negatively correlated with serum PSA (r300=-0.58,P<0.01;r800=-0.60,P<0.01;r1 000=-0.66,P<0.01) before endocrine therapy.ADC value was also negatively correlated with serum PSA (r300=-0.55,P<0.01;r800=-0.52,P<0.01;r1 000=-0.61,P<0.01) after endocrine therapy.In addition,SI was negatively correlated with serum PSA (r300=-0.09,P<0.01;r800=-0.18,P<0.01;r1 000=-0.28,P<0.01) before the treatment, as well.Conclusion ADC value at different b values increased after endocrine therapy in Pca, and is negatively correlated with serum PSA.The correlation is the most significant at b value of 1 000 s/mm2.The combination of DWI and serum PSA could be used to monitor and evaluate the effect of endocrinotherapy for Pca, and better guide the clinical treatment of Pca.

Value of 3.0T magnetic resonance multi-b value diffusion-weighted imaging in efficacy evaluation of chemotherapy for central lung cancer with atelectasis / 肿瘤研究与临床

Objective To evaluate the value of 3.0T magnetic resonance multi-b value diffusion-weighted imaging (DWI) in evaluating the efficacy of chemotherapy for patients with central lung squamous cell carcinoma and atelectasis. Methods Twenty patients with lung squamous cell carcinoma were examined by magnetic resonance imaging (MRI) (including T1WI, T2WI and multi-b value DWI) before chemotherapy, 2 cycles of chemotherapy and 4 cycles of chemotherapy. The images, the tumor volume and changes of apparent diffusion coefficient (ADC) were analyzed. Results In the patients with central lung cancer and atelectasis, the tumor and atelectasis could be distinguished on MRI examination before radiotherapy. It was more easily identified on T2WI images after radiotherapy. In the 20 patients, the ADC values in the effective group (partial remission or complete remission) and the invalid group were increased, but the differences of ADC values in the effective group before chemotherapy, 2 cycles and 4 cycles of chemotherapy were statistically significant [b=800 s/mm2:(1.09 ± 0.52) × 10-6 mm2/s, (1.22 ± 0.59) × 10-6 mm2/s, (1.24 ± 0.52) × 10-6 mm2/s, F = 31.19, P < 0.001]. There was no significant difference in ADC values between before and after chemotherapy (b = 800 s/mm2: (1.10 ± 0.49) × 10-6 mm2/s, (1.16 ± 0.60) × 10-6 mm2/s, (1.20 ± 0.72) × 10-6 mm2/s, F=2.86, P=0.089]. When b=800 s/mm2, the ADC curve slope in the effective group was more stable, better linearity. Conclusions The MRI technique can accurately distinguish the tumor from atelectasis before and after chemotherapy. The change of ADC value after chemotherapy is earlier than that of morphological change. The change rate of b value can better evaluate the curative effect of chemotherapy.

The value of ultra-high-b-value diffusion weighted imaging in thediagnosis of prostate cancer at 1.5T MR / 实用放射学杂志

Objective To evaluate the ability of ultra-high-b-value diffusion weighted imaging (DWI) in diagnosis of the prostate cancer (PCa) at 1.5T MR.Methods 12 patients with PCa and 17 patients with benign prostate hyperplasia (BPH) proved by histopathology underwent MRI and DWI examinations (b=400, 800,1 400 s/mm2).The signal intensity and visual degree of region of interest (ROI) in all DWI with different b values were respectively measured.The signal intensity and visual degree of ROI between high-b-value DWI and ultra-high-b-value DWI were compared,respectively.Results The difference of signal intensity of PCa between high-b-value DWI and ultra-high-b-value DWI was statistically significant (χ2=220.957,P=0.000<0.05).The signal intensity of PCa was getting brighter in DWI with higher b value.The difference of visual degree between these two groups was also statistically significant (χ2=11.378,P=0.003<0.05).The difference among PCa, BPH and normal prostate peripheral zone was statistically significant in ultra-high-b-value DWI (χ2=25.913, P=0.000<0.05).The brightness of PCa in ultra-high-b-value DWI mainly was bright or grey-bright (71.4%), while the brightness of BPH and normal prostate peripheral zone were mainly dark or grey-dark (BPH 63.0%, normal prostate peripheral zone 73.3%).The difference of visual degree among PCa, BPH and normal prostate peripheral zone was statistically significant difference as well (Z=-6.908,-6.110,P=0.000<0.017).The diagnostic efficiency of the signal intensity and visual degree were highest with b=1 400 s/mm2.Conclusion DWI with ultra-high-b-value can improve the display rate of the PCa at 1.5T MR, making easier the detection and diagnosis of PCa.

Preliminary study on change trends of apparent diffusion coefficient under different b values of diffusion-weighted imaging in acute cerebral infarction / 重庆医学

Objective To investigate the change trends of apparent diffusion coefficient (ADC) values under different b values of diffusion‐weighted imaging(DWI) in acute cerebral infarction .Methods The patients with acute celebral infarction were selected as the experimental group and the normal volunteers as the control group .The 5 different diffusion gradients were used ,including b=200 s/mm2 ,b=400 s/mm2 ,b=600 s/mm2 ,b=800 s/mm2 and b=1 000 s/mm2 .The two pairs of 20 cases of acute cerebral in‐farction and 20 healthy volunteers were performed the DWI scanning for detecting the ADC value under different b values .The ADC values in the two groups were statistically analyzed by using one‐way anova .Results In 5 different b values ,the ADC values in the case group was 0 .64 ,0 .59 ,0 .55 ,0 .47 and 0 .41 respectively ,which in the control group were 1 .04 ,0 .99 ,0 .92 ,0 .85 and 0 .78 re‐spectively ,the differences between the two groups were statistically significant ,moreover with the b value increase ,the ADC value had a decreasing trend(P< 0 .01) .Conclusion The ADC value in the patients with acute cerebral infarction is significantly de‐creased ,the ADC values are different under different b values of DWI ,moreover which shows the significantly negative correlation trend .

The evaluation of color and color difference according to the layering placement of Incisal shade composites on the body composites of the indirect resin restoration / 대한치과보존학회지

OBJECTIVES: The aim of this study was to evaluate the surface color of indirect resin restoration according to the layering placement of different shade of incisal composite. MATERIALS AND METHODS: In this study, CIE L*a*b* value of 16 Body composite of Tescera ATL (Bisco, Schaumburg IL,USA) was measured by spectrophotometer (NF999, Nippon Denshuku, Japan), and compared to CIE L*a*b* value of Vitapan shade guide. Nine shade Incisal composite of Tescera ATL were build-up to 1 mm thickness on Body composites inlay block, and CIE L*a*b* value was measured. Incisal composite was ground to 0.5 mm thickness and CIE L*a*b* value was re-measured. Color difference between Body composite and Incisal composites layered on Body composite was calculated as a function of thickness. RESULTS: Color difference between corresponding shade of Tescera Body composite and Vitapan shade guide was from 6.88 to 12.80. L* and b*value was decreased as layering thickness of Incisal composite on Body composite was increased. But, a* value did not show specific change tendency. CONCLUSIONS: Surface color difference between Body composites and Incisal composites layered on Body composite was increased as the layering thickness of Incisal composite increased (p < 0.05).

SNR and ADC Changes at Increasing b Values among Patients with Lumbar Vertebral Compression Fracture on 1.5T MR Diffusion Weighted Images / 의학물리

To examine among patients with vertebral compression fracture the extent to which signal-to-noise ratio (SNR) and Apparent Diffusion Coefficient (ADC) values at the lumbar vertebral compression fracture site vary on diffusion-weighted MR images according to varying b values on the 1.5T MR device. Diffusion-weighted MR images of 30 patients with compression fracture due to chronic osteoporosis who underwent vertebral MRI from Jan. 2008 to Nov. 2009 were respectively obtained using a 1.5-T MR scanner with the b values increased from 400, 600, 800, 1,000 to 1,200 s/mm2. For diffusion-weighted MR images with different b values, the signal-to-noise ratio (SNR) was assessed at three sites: the site of compression fracture of the lumbar vertebral body at L1 to L5, and both the upper and lower discs of the said fracture site, while for ADC map images with different b values, the SNR and ADC were respectively assessed at those three sites. As a quantitative analysis, diffusion-weighted MR images and ADC map images with b value of 400 s/mm2 (the base b values) were respectively compared with the corresponding images with each different b value. As far as qualitative analysis is concerned, for both diffusion-weighted MR and ADC map images with b value of 400 s/mm2, the extent to which signal intensity values obtained at the site of compression fracture of the lumbar vertebral body at L1 to L5 vary according to the increasing b values were examined. The quantitative analysis found that for both diffusion-weighted MR and ADC map images, as the b values increased, the SNR were relatively lowered at all the three sites, compared to the base b value. Also, it was found that as the b values increased, ADC values were relatively lowered at all the three sites on ADC map images. On the other hand, the qualitative analysis found that as the b values increased to more than 400 s/mm2, the signal intensity gradually decreased at all the sites, while at the levels of more than 1,000 s/mm2, severe image noises appeared at all of the three sites. In addition, higher signal intensity was found at the site of compression fracture of the lumbar vertebral body than at the discs. Findings showed that with the b value being increased, both the signal-to-noise ratio (SNR) and Apparent Diffusion Coefficient (ADC) values gradually decreased at all the sites of the lumbar vertebral compression fracture and both the upper and lower discs of the fracture site, suggesting that there is a possibility of a wider range of applications to assessment of various vertebral pathologies by utilizing multi b values in the diffusion-weighted MRI examination.

The value of DWI in diagnosis and differential diagnosis of pancreatic carcinoma from chronic lump type pancreatitis / 中华胰腺病杂志

Objective To evaluate the ability of diffusion-weighted imaging (DWI)in differentiating pancreatic carcinoma from chronic lump type pancreatitis. Methods Totally 38 cases of pancreatic cancer, 9 cases of chronic lump type pancreatitis, 15 cases of normal patients underwent DWI. DWI with b value＝0, 500, 1 000 s/mm2 was performed twice. Apparent diffusion coefficient (ADC) was measured by analysis of imagines of ADC. Results The mean ADC value of 38 subjects with pancreatic carcinoma was (1.411± 0.101)×10-3 mm2/sec, the mean ADC value of 9 subjects with lump type pancreatitis was (1.053±0.113) ×10-3 mm2/sec, and the mean ADC value of normal pancreas subjects was (1.245±0.112)×10-3 mm2/s. The difference between the three groups were statistically significant (P＜0.05). Conclusions DWI may have the clinical potential to differentiate chronic lump type pancreatitis from pancreatic carcinoma.

Diffusion-weighted Single-shot Echo Planar MR Imaging of Normal Human Prostate Using Different b Values / 华中科技大学学报（医学）（英德文版）

This study examined the effect of different b values on diffusion-weighted MR imaging (DWI) of human prostate by using single-shot spin echo echo planar imaging (SE-EP1) sequences,observed the normal appearances and measured apparent diffusion coefficient (ADC) values in anatomical regions of normal prostate. Twenty-four healthy volunteers (mean age: 32 y) were studied by using a 1.ST system with a phased array surface multicoil. Two kinds of single-shot SE-EPI sequence were used to perform DWI in the prostate in volunteers, with five b values being 0, 30, 300, 500 to 1000 s/mm2. The image quality with different imaging parameters was analyzed and the ADC values in anatomical regions of normal prostate were measured. DWI of prostate was successfully obtained in all volunteers. The images were of good quality, without artifacts containing pixels within the prostate. The contrast was good between the different anatomical regions of the prostatic gland, i.e.,the peripheral zone (PZ), which exhibited higher signal intensity, and the central gland (CG). Signal intensity contrast was related to the magnitude of b values. The ADC values in PZ and CG were (1.27±0.22)× 10-3 mm2/s and (1.01±0.17)× 10-3 mm2/s, respectively. The ADC values were found to he significantly higher in PZ than in CG (P<0.05, paired t-test). Significant differences were found between the slice-selecting component and both the read-out and phase-encoding components of the ADC values. It is concluded that SE-EPI is a suitable DWI sequence for human prostate. The contrast between PZ and CG is good when b values are low, while the diffusion and ADC values are accurate when b values are high. ADC values are higher in PZ than in CG in normal prostate. Diffusional anisotropy is present in normal prostatic tissue.