The usefulness of diffusion-weighted magnetic resonance imaging （DWI） in the evaluation of scrotal pathology has recently been reported. A standard reference of normal testicular apparent diffusion coefficient （ADC...The usefulness of diffusion-weighted magnetic resonance imaging （DWI） in the evaluation of scrotal pathology has recently been reported. A standard reference of normal testicular apparent diffusion coefficient （ADC） values and their variations with age is necessary when interpreting normal testicular anatomy and pathology. We evaluated 147 normal testes using DWI, including 71 testes from 53 men aged 20-39years （group 1）, 67 testes from 42 men aged 40-69 years （group 2） and nine testes from six men older than 70years （group 3）. DWI was performed along the axial plane, using a single shot, multislice spin-echo planar diffusion pulse sequence and b-values of 0 and 900 s mm-2. The mean and standard deviation of the ADC values of normal testicular parenchyma were calculated for each age group separately. Analysis of variance （ANOVA） followed by post hoc analysis （Dunnett T3） was used for statistical purposes. The ADC values （x 10-3 mm2s-1） of normal testicular tissue were different among age groups （group 1：1.08 ± 0.13; group 2：1.15 ±0.15 and group 3：1.31± 0.22）. ANOVA revealed differences in mean ADC among age groups （F= 11.391, P〈 0.001）. Post hoc analysis showed differences between groups 1 and 2 （P= 0.008） and between groups 1 and 3 （P= 0.043）, but not between groups 2 and 3 （P= 0.197）. Our findings suggest that ADC values of normal testicular tissue increase with advancing age.展开更多
Purpose: Commonly used diffusion weighted (DW) imaging such as DW spin echo (SE) type echo planar imaging (DW-SE-EPI) is known to be a snapshot-like acquisition and to have a relatively high signal-to-noise ratio. Spi...Purpose: Commonly used diffusion weighted (DW) imaging such as DW spin echo (SE) type echo planar imaging (DW-SE-EPI) is known to be a snapshot-like acquisition and to have a relatively high signal-to-noise ratio. Spiral MRI sequence (SPIRAL) has characteristics similar to these of EPI, but it has rarely been used for diffusion-weighted imaging (DWI). In vivo DW-SPIRAL of the rat brain has almost never been reported. Our purpose in this study was to examine the potential of SE-type two-dimensional (2D) multi-shot spiral acquisition MRI for apparent diffusion coefficient (ADC) mapping of the rat brain in vivo. Materials and Methods: We made an SE-type DW-2D-spiral MRI sequence (DW-SPIRAL) which was prepared on a 2.0-T animal-experiment MR scanner. Comparing the phantom experimental result of DW-SPIRAL with the phantom experimental result of DW SE-type echo-planar imaging (DW-SE-EPI) and conventional DW spin echo imaging (DW-SE), we estimated the characteristics of DW-SPIRAL and assessed the clinical application of DW-SPIRAL in an animal experiment on the rat brain. Results: There was not much difference between the calculated water/glycerol phantom diffusion coefficient of DW-SPIRAL and the calculated diffusion coefficient of DW-SE. This result shows that the DW-SPIRAL sequence is appropriate for use in diffusion weighted imaging. There were fewer phantom image distortions and ghosting artifacts with DW-SPIRAL than with DW-SE-EPI, and this tendency was similar in the animal experiment on the rat brain. Conclusion: The DW-SPIRAL sequence had been successfully tested in phantom experiments and rat brain experiments. It has been demonstrated that the DW-SPIRAL sequence is capable of producing in vivo rat brain DWI.展开更多
Diffusion-weighted imaging (DWI) as a new technique of magnetic resonance imaging (MRI) is used to detect focal hepatic lesions. This study was designed to evaluate the significance of DWI to differentiate focal hepat...Diffusion-weighted imaging (DWI) as a new technique of magnetic resonance imaging (MRI) is used to detect focal hepatic lesions. This study was designed to evaluate the significance of DWI to differentiate focal hepatic lesions less than 3 cm in diameter by the quantitation of apparent diffusion coefficient (ADC) values. METHODS:DWI using 1.5T MRI scanner unit was performed with a spin-echo single-shot echo planar imaging (EPI) in 56 cases of small focal hepatic lesions, including hepatocellular carcinoma (11), hepatic metastatic tumor (15 ), hepatic cavernous hemangioma (14), and hepatic cyst (16).The ADC values of these lesions were calculated respectively. The ratios of the ADC values of lesion/liver in hepatocellular carcinomas and hepatic metastatic tumors were also estimated. RESULTS:The mean ADC values (mm2/s) were (0.93±0.06) ×10-3 in hepatocellular carcinomas, (1.09±0.18)×10-3 in hepatic metastatic tumors,(1.95±0.38)×10-3 in hepatic cavernous hemangiomas, and (3.18±0.33) ×10-3 in hepatic cysts. The ratios of ADC values of lesion/liver were 0.90±0.06 and 1.15±0.14 in hepatocellular carcinoma and hepatic metastatic tumors respectively, which were significantly different (P<0.05). CONCLUSION:The measurement of ADC values and the ratios of ADC values of lesion/liver are helpful in MR diagnosis and differentiation of focal hepatic lesions.展开更多
AIM:To investigate the use of multi-b-value diffusionweighted imaging in diagnosing pancreatic cancer.METHODS:We retrospectively analyzed 33 cases of pancreatic cancer and 12 cases of benign pancreatic tumors at the S...AIM:To investigate the use of multi-b-value diffusionweighted imaging in diagnosing pancreatic cancer.METHODS:We retrospectively analyzed 33 cases of pancreatic cancer and 12 cases of benign pancreatic tumors at the Second Affiliated Hospital of Kunming Medical University from December 2008 to January2011.The demographic characteristics,clinical presentation,routine magnetic resonance imaging and diffusion weighted imaging(DWI)features with different b values were reviewed.Continuous data were expressed as mean±SD.Comparisons between pancreatic cancer and benign pancreatic tumors were performed using the Student’s t test.A probability of P<0.05 was considered statistically significant.RESULTS:Thirty-three patients with pancreatic cancer were identified.The mean age at diagnosis was 60±5.6 years.The male:female ratio was 21:12.Twenty cases were confirmed by surgical resection and 13 by biopsy of metastases.T1 weighted images demonstrated a pancreatic head mass in 16 patients,a pancreatic body mass in 10 cases,and a pancreatic tail mass with pancreatic atrophy in 7 cases.Eight patients had hepatic metastases,13 had invasion or envelopment of mesenteric vessels,4 had bone metastases,and 8had lymph node metastases.DWI demonstrated an irregular intense mass with unclear margins.Necrotic tissue demonstrated an uneven low signal.A b of 1100s/mm2was associated with a high intensity signal with poor anatomical delineation.A b of 700 s/mm2was associated with apparent diffusion coefficients(ADCs)that were useful in distinguishing benign and malignant pancreatic tumors(P<0.05).b values of 50,350,400,450 and 1100 s/mm2were associated with ADCs that did not differentiate the two tumors.CONCLUSION:Low b value images demonstrated superior anatomical details when compared to high b value images.Tumor tissue definition was high and contrast with the surrounding tissues was good.DWI was useful in diagnosing pancreatic cancer.展开更多
Aim: To investigate the diagnostic efficiency of apparent diffusion coefficient value (ADC) in differentiating benign from malignant breast lesions at 3.0 T diffusion-weighted imaging with different pair of b value. M...Aim: To investigate the diagnostic efficiency of apparent diffusion coefficient value (ADC) in differentiating benign from malignant breast lesions at 3.0 T diffusion-weighted imaging with different pair of b value. Methods: Total 110 patients with 107 lesions (44 benign and 63 malignant) were selected for our study with five different b-values 0, 400, 800, 1200 and 1600 s/mm<sup>2</sup>. ADC values were calculated using different pairs of b values. The cut-off ADC values and diagnostic efficiency were evaluated by receiver operating characteristic analysis. Comparison of Mean ADC value for breast lesions was determined by using independent sample t test. ROC curves were used for diagnostic efficiency of ADC using different pairs of b values. Results: With increase of b value, mean ADC value decreases. The mean ADC values for benign were 1.73 × 10<sup>-3</sup> mm<sup>2</sup>/s for b 0 and 400, 1.57 × 10<sup>-3</sup> mm<sup>2</sup>/s for b 0 and 800, 1.43 × 10<sup>-3</sup> mm<sup>2</sup>/s for b 0 and 1200 and 1.30 × 10<sup>-3</sup> mm<sup>2</sup>/s for b 0 and 1600 s/mm<sup>2</sup>. The mean ADC values for the malignant breast lesion were 1.21 × 10<sup>-3</sup> mm<sup>2</sup>/s for b 0 and 400, 1.06 × 10<sup>-3</sup> mm<sup>2</sup>/s for b 0 and 800, 0.94 × 10<sup>-3</sup> mm<sup>2</sup>/s for b 0 and 1200 and 0.86 × 10<sup>-3</sup> mm<sup>2</sup>/s for b 0 and 1600 s/mm<sup>2</sup>. ADC diagnostic efficiency for benign and malignant lesion for all the pair of b value combination was significant (p > 0.05). The sensitivity, specificity, PPV, NPV and accuracy were 80.95%, 90.9%, 92.72%, 76.92%, 85.04% for b 0 and 400;84.12%, 90.9%, 92.98%, 80%, 86.91% for b 0 and 800;84.12%, 90.9%, 92.98%, 80%, 86.91% for b 0 and 1200;84.12%, 90.9%, 92.98%, 80%, 86.91% for b 0 and 1600 s/mm<sup>2</sup> respectively. Conclusion: DWI is effective in differentiating benign and malignant breast lesion at 3.0 Tesla using ADC with higher b value combination.展开更多
Background Diffusion-weighted imaging has been widely used to differentiate the character of lymphadenopathy. But there are significant differences between prior studies. The aim of the study was to compare the benefi...Background Diffusion-weighted imaging has been widely used to differentiate the character of lymphadenopathy. But there are significant differences between prior studies. The aim of the study was to compare the benefit of apparent diffusion coefficient （ADC） and rADC in the differentiation of metastatic and benign lymph nodes in a rabbit model. Methods Two observers independently measured ADCs in quadriceps of every rabbit on diffusion-weighted images with different sizes of regions of interest （ROI）. The appropriate ROI for rADC was determined using the interobserver coefficient, rADC was calculated by AOClesion/AOCreference site- Receiver operating characteristics （ROC） analysis was performed to compare the diagnostic value of the ADC values and rADC values in differentiating metastatic from benign lymph nodes. Results When the ROIs included five pixels, the ICC was 0.816, indicating a good interobserver agreement. The differences of ADC and rADC values between metastatic and benign lymph nodes were both statistically significant. The area under the ROC curve was greater for the rADC than for the ADC. With the rADC criteria of 0.640, the sensitivity and specificity for differentiating metastatic from benign lymph nodes were 93% and 90%, respectively. Conclusion As a reference site, muscles reveal a good repeatability using a small ROI and the rADC may improve diagnostic accuracy for detecting metastatic nodes in animal models.展开更多
Objective： Noninvasive diffusion-weighted magnetic resonance imaging （DWI） is a well-studied MR imaging technique for quantifying water diffusion especially in tumor area. The correlation between apparent diffusion...Objective： Noninvasive diffusion-weighted magnetic resonance imaging （DWI） is a well-studied MR imaging technique for quantifying water diffusion especially in tumor area. The correlation between apparent diffusion coefficient （ADC） value and apoptosis or proliferation is not clear by now. This study aimed to investigate whether DWI-ADC value could be used as an imaging marker related with pathologic indexes of tumors. Methods： A total of 3 0 Balb/c mice with HT2 9 colorectal carcinoma were subjected to DWI and histologic analysis. The percentage of ADC changes and the apoptotic and proliferating indexes were calculated at predefined time points. Kolmogorov-Smirnov distances were considered to determine whether the percentage of ADC changes, and the apoptotic and proliferating indexes were normally distributed. An independent-samples t-test was used to analyze the difference between apoptotic and proliferating indexes in the two groups. Results： There was a statistically significant difference in proliferating index between the radiotherapy and control groups （mean proliferating index： 49.27% vs. 83.09%）, and there was a statistically significant difference in apoptotic index between the two groups （mean apoptotic index： 37.7% vs. 2.71%）. A significant positive correlation was found between the percentage of ADC changes of the viable tissue and apoptotic index. Pearson＇s correlation coefficient was 0.655 （P=0.015）. A significant negative correlation was found between the percentage of ADC changes of the viable tissue and ki-67 proliferation index. Pearson＇s correlation coefficient was 0.734 （P〈0.001）. Conclusions： Our results suggest that ADC proliferating indexes in colorectal carcinoma. value may be used in measurement of cell apoptotic and展开更多
目的探析T2加权成像(T_(2)WI)联合扩散加权成像(DWI)用于直肠诊断及术前分期的效能及其相对表观扩散系数(rADC)、表观扩散系数(ADC)值与患者临床特征的相关性。方法选择疑似直肠癌患者212例,其中男性118例,女性94例;年龄42~83岁,平均年...目的探析T2加权成像(T_(2)WI)联合扩散加权成像(DWI)用于直肠诊断及术前分期的效能及其相对表观扩散系数(rADC)、表观扩散系数(ADC)值与患者临床特征的相关性。方法选择疑似直肠癌患者212例,其中男性118例,女性94例;年龄42~83岁,平均年龄60.93岁;病程3个月~10年,平均病程5.64年。均行T_(2)WI联合DWI检查,以患者最终病理诊断结果为标准,计算T_(2)WI联合DWI对直肠癌的诊断效能,进行T、N分期诊断;以最终病理诊断结果为依据,计算其T、N分期诊断效能,并进行一致性检验;观察不同临床特征的患者间rADC、ADC值差异,绘制受试者工作特性(ROC)曲线,计算rADC、ADC值对直肠癌的诊断效能。结果术后病理诊断恶性172例,良性40例。T1期、T2期、T3期、T4期分别为8例、35例、31例、6例,N0期、N1期、N2期分别为37例、22例、21例。T_(2)WI联合DWI诊断直肠癌的准确度为92.45%,灵敏度为93.02%,特异度为90.00%;分期诊断中T1期、T2期、T3期、T4期诊断准确度为95.00%、93.75%、96.26%、95.00%,灵敏度为75.00%、94.12%、93.55%、71.43%,特异度为97.22%、95.65%、95.92%、97.26%。一致性检验显示T_(2)WI联合DWI与病理诊断结果的T分期诊断一致性较好(Kappa=0.863,P=0.000);N分期诊断中N0期、N1期、N2期诊断准确度分别为93.75%、90.00%、96.25%,灵敏度分别为94.59%、77.27%、95.24%,特异度分别为93.02%、94.83%、96.61%,一致性检验提示T_(2)WI联合DWI与病理诊断的N分期诊断一致性较好(Kappa=0.844,P=0.000);病变特征与rADC、ADC分析中,恶性病变rADC、ADC显著低于良性病变(0.84±0.09 vs 1.18±0.12、0.93±0.11 vs 1.39±0.11。P<0.05)。腺癌rADC、ADC显著高于黏液腺癌(0.89±0.11 vs 0.75±0.09、0.97±0.14 vs 0.83±0.11。P<0.05)。不同分化程度患者间rADC、ADC从高至低依次为高分化、中分化、低分化(rADC:0.95±0.16 vs 0.82±0.10 vs 0.72±0.08;ADC:1.05±0.17 vs 0.911±0.14 vs 0.81±0.09。P<0.05)。ADC诊断直肠癌AUC为0.987,灵敏度为92.44%,特异度为97.50%(P<0.001);rADC诊断结直肠癌AUC为0.941,灵敏度为92.44%,特异度为87.50%(P<0.001)。结论T_(2)WI联合DWI诊断直肠癌具有良好的诊断效能,且其术前T、N分期准确度高,与病理诊断一致性较好。rADC、ADC值在不同良恶性肿瘤、不同分化等级肿瘤、不同病理类型肿瘤间存显著差异,可作为良恶性及肿瘤分化程度的诊断依据。展开更多
目的探讨DWI表观扩散系数(apparent diffusion coefficient,ADC)值对鉴别肺部良、恶性病变的价值及b值优化。方法对82例肺部结节或肿块行常规MRI和DWI检查,分别测量b值为300、500、800s/mm2时的病变ADC值。比较同一b值下良、恶性病变AD...目的探讨DWI表观扩散系数(apparent diffusion coefficient,ADC)值对鉴别肺部良、恶性病变的价值及b值优化。方法对82例肺部结节或肿块行常规MRI和DWI检查,分别测量b值为300、500、800s/mm2时的病变ADC值。比较同一b值下良、恶性病变ADC值的差异。根据受试者工作特征曲线(r e c e i v e o p e r a t i n g characteristic curve,ROC)评价不同b值下ADC值鉴别肺部良恶性病变的诊断效能。结果 82个病例中恶性病变54例,良性病变28例。不同b值下恶性病变的平均AD均值均明显小于良性病变平均ADC值,差异均有统计学意义(P均<0.05)。b值取300、500、800s/mm2,AUC分别为0.806,0.838,0.826,均有诊断意义(AUC>0.5);其中b=500s/mm2时ADC值诊断效能最高,ADC阈值为1.492×10-3mm2/s,其敏感度、特异度、准确度分别为88.9%、78.6%、85.92%。结论 ADC值有助于鉴别肺部良恶病变,b值取500s/mm2时诊断效能较高。展开更多
文摘The usefulness of diffusion-weighted magnetic resonance imaging （DWI） in the evaluation of scrotal pathology has recently been reported. A standard reference of normal testicular apparent diffusion coefficient （ADC） values and their variations with age is necessary when interpreting normal testicular anatomy and pathology. We evaluated 147 normal testes using DWI, including 71 testes from 53 men aged 20-39years （group 1）, 67 testes from 42 men aged 40-69 years （group 2） and nine testes from six men older than 70years （group 3）. DWI was performed along the axial plane, using a single shot, multislice spin-echo planar diffusion pulse sequence and b-values of 0 and 900 s mm-2. The mean and standard deviation of the ADC values of normal testicular parenchyma were calculated for each age group separately. Analysis of variance （ANOVA） followed by post hoc analysis （Dunnett T3） was used for statistical purposes. The ADC values （x 10-3 mm2s-1） of normal testicular tissue were different among age groups （group 1：1.08 ± 0.13; group 2：1.15 ±0.15 and group 3：1.31± 0.22）. ANOVA revealed differences in mean ADC among age groups （F= 11.391, P〈 0.001）. Post hoc analysis showed differences between groups 1 and 2 （P= 0.008） and between groups 1 and 3 （P= 0.043）, but not between groups 2 and 3 （P= 0.197）. Our findings suggest that ADC values of normal testicular tissue increase with advancing age.
文摘Purpose: Commonly used diffusion weighted (DW) imaging such as DW spin echo (SE) type echo planar imaging (DW-SE-EPI) is known to be a snapshot-like acquisition and to have a relatively high signal-to-noise ratio. Spiral MRI sequence (SPIRAL) has characteristics similar to these of EPI, but it has rarely been used for diffusion-weighted imaging (DWI). In vivo DW-SPIRAL of the rat brain has almost never been reported. Our purpose in this study was to examine the potential of SE-type two-dimensional (2D) multi-shot spiral acquisition MRI for apparent diffusion coefficient (ADC) mapping of the rat brain in vivo. Materials and Methods: We made an SE-type DW-2D-spiral MRI sequence (DW-SPIRAL) which was prepared on a 2.0-T animal-experiment MR scanner. Comparing the phantom experimental result of DW-SPIRAL with the phantom experimental result of DW SE-type echo-planar imaging (DW-SE-EPI) and conventional DW spin echo imaging (DW-SE), we estimated the characteristics of DW-SPIRAL and assessed the clinical application of DW-SPIRAL in an animal experiment on the rat brain. Results: There was not much difference between the calculated water/glycerol phantom diffusion coefficient of DW-SPIRAL and the calculated diffusion coefficient of DW-SE. This result shows that the DW-SPIRAL sequence is appropriate for use in diffusion weighted imaging. There were fewer phantom image distortions and ghosting artifacts with DW-SPIRAL than with DW-SE-EPI, and this tendency was similar in the animal experiment on the rat brain. Conclusion: The DW-SPIRAL sequence had been successfully tested in phantom experiments and rat brain experiments. It has been demonstrated that the DW-SPIRAL sequence is capable of producing in vivo rat brain DWI.
基金This study was supported by the Natural Science Foundation of Guangdong Province, China (No.101595 and No. 32830).
文摘Diffusion-weighted imaging (DWI) as a new technique of magnetic resonance imaging (MRI) is used to detect focal hepatic lesions. This study was designed to evaluate the significance of DWI to differentiate focal hepatic lesions less than 3 cm in diameter by the quantitation of apparent diffusion coefficient (ADC) values. METHODS:DWI using 1.5T MRI scanner unit was performed with a spin-echo single-shot echo planar imaging (EPI) in 56 cases of small focal hepatic lesions, including hepatocellular carcinoma (11), hepatic metastatic tumor (15 ), hepatic cavernous hemangioma (14), and hepatic cyst (16).The ADC values of these lesions were calculated respectively. The ratios of the ADC values of lesion/liver in hepatocellular carcinomas and hepatic metastatic tumors were also estimated. RESULTS:The mean ADC values (mm2/s) were (0.93±0.06) ×10-3 in hepatocellular carcinomas, (1.09±0.18)×10-3 in hepatic metastatic tumors,(1.95±0.38)×10-3 in hepatic cavernous hemangiomas, and (3.18±0.33) ×10-3 in hepatic cysts. The ratios of ADC values of lesion/liver were 0.90±0.06 and 1.15±0.14 in hepatocellular carcinoma and hepatic metastatic tumors respectively, which were significantly different (P<0.05). CONCLUSION:The measurement of ADC values and the ratios of ADC values of lesion/liver are helpful in MR diagnosis and differentiation of focal hepatic lesions.
文摘AIM:To investigate the use of multi-b-value diffusionweighted imaging in diagnosing pancreatic cancer.METHODS:We retrospectively analyzed 33 cases of pancreatic cancer and 12 cases of benign pancreatic tumors at the Second Affiliated Hospital of Kunming Medical University from December 2008 to January2011.The demographic characteristics,clinical presentation,routine magnetic resonance imaging and diffusion weighted imaging(DWI)features with different b values were reviewed.Continuous data were expressed as mean±SD.Comparisons between pancreatic cancer and benign pancreatic tumors were performed using the Student’s t test.A probability of P<0.05 was considered statistically significant.RESULTS:Thirty-three patients with pancreatic cancer were identified.The mean age at diagnosis was 60±5.6 years.The male:female ratio was 21:12.Twenty cases were confirmed by surgical resection and 13 by biopsy of metastases.T1 weighted images demonstrated a pancreatic head mass in 16 patients,a pancreatic body mass in 10 cases,and a pancreatic tail mass with pancreatic atrophy in 7 cases.Eight patients had hepatic metastases,13 had invasion or envelopment of mesenteric vessels,4 had bone metastases,and 8had lymph node metastases.DWI demonstrated an irregular intense mass with unclear margins.Necrotic tissue demonstrated an uneven low signal.A b of 1100s/mm2was associated with a high intensity signal with poor anatomical delineation.A b of 700 s/mm2was associated with apparent diffusion coefficients(ADCs)that were useful in distinguishing benign and malignant pancreatic tumors(P<0.05).b values of 50,350,400,450 and 1100 s/mm2were associated with ADCs that did not differentiate the two tumors.CONCLUSION:Low b value images demonstrated superior anatomical details when compared to high b value images.Tumor tissue definition was high and contrast with the surrounding tissues was good.DWI was useful in diagnosing pancreatic cancer.
文摘Aim: To investigate the diagnostic efficiency of apparent diffusion coefficient value (ADC) in differentiating benign from malignant breast lesions at 3.0 T diffusion-weighted imaging with different pair of b value. Methods: Total 110 patients with 107 lesions (44 benign and 63 malignant) were selected for our study with five different b-values 0, 400, 800, 1200 and 1600 s/mm<sup>2</sup>. ADC values were calculated using different pairs of b values. The cut-off ADC values and diagnostic efficiency were evaluated by receiver operating characteristic analysis. Comparison of Mean ADC value for breast lesions was determined by using independent sample t test. ROC curves were used for diagnostic efficiency of ADC using different pairs of b values. Results: With increase of b value, mean ADC value decreases. The mean ADC values for benign were 1.73 × 10<sup>-3</sup> mm<sup>2</sup>/s for b 0 and 400, 1.57 × 10<sup>-3</sup> mm<sup>2</sup>/s for b 0 and 800, 1.43 × 10<sup>-3</sup> mm<sup>2</sup>/s for b 0 and 1200 and 1.30 × 10<sup>-3</sup> mm<sup>2</sup>/s for b 0 and 1600 s/mm<sup>2</sup>. The mean ADC values for the malignant breast lesion were 1.21 × 10<sup>-3</sup> mm<sup>2</sup>/s for b 0 and 400, 1.06 × 10<sup>-3</sup> mm<sup>2</sup>/s for b 0 and 800, 0.94 × 10<sup>-3</sup> mm<sup>2</sup>/s for b 0 and 1200 and 0.86 × 10<sup>-3</sup> mm<sup>2</sup>/s for b 0 and 1600 s/mm<sup>2</sup>. ADC diagnostic efficiency for benign and malignant lesion for all the pair of b value combination was significant (p > 0.05). The sensitivity, specificity, PPV, NPV and accuracy were 80.95%, 90.9%, 92.72%, 76.92%, 85.04% for b 0 and 400;84.12%, 90.9%, 92.98%, 80%, 86.91% for b 0 and 800;84.12%, 90.9%, 92.98%, 80%, 86.91% for b 0 and 1200;84.12%, 90.9%, 92.98%, 80%, 86.91% for b 0 and 1600 s/mm<sup>2</sup> respectively. Conclusion: DWI is effective in differentiating benign and malignant breast lesion at 3.0 Tesla using ADC with higher b value combination.
文摘Background Diffusion-weighted imaging has been widely used to differentiate the character of lymphadenopathy. But there are significant differences between prior studies. The aim of the study was to compare the benefit of apparent diffusion coefficient （ADC） and rADC in the differentiation of metastatic and benign lymph nodes in a rabbit model. Methods Two observers independently measured ADCs in quadriceps of every rabbit on diffusion-weighted images with different sizes of regions of interest （ROI）. The appropriate ROI for rADC was determined using the interobserver coefficient, rADC was calculated by AOClesion/AOCreference site- Receiver operating characteristics （ROC） analysis was performed to compare the diagnostic value of the ADC values and rADC values in differentiating metastatic from benign lymph nodes. Results When the ROIs included five pixels, the ICC was 0.816, indicating a good interobserver agreement. The differences of ADC and rADC values between metastatic and benign lymph nodes were both statistically significant. The area under the ROC curve was greater for the rADC than for the ADC. With the rADC criteria of 0.640, the sensitivity and specificity for differentiating metastatic from benign lymph nodes were 93% and 90%, respectively. Conclusion As a reference site, muscles reveal a good repeatability using a small ROI and the rADC may improve diagnostic accuracy for detecting metastatic nodes in animal models.
文摘Objective： Noninvasive diffusion-weighted magnetic resonance imaging （DWI） is a well-studied MR imaging technique for quantifying water diffusion especially in tumor area. The correlation between apparent diffusion coefficient （ADC） value and apoptosis or proliferation is not clear by now. This study aimed to investigate whether DWI-ADC value could be used as an imaging marker related with pathologic indexes of tumors. Methods： A total of 3 0 Balb/c mice with HT2 9 colorectal carcinoma were subjected to DWI and histologic analysis. The percentage of ADC changes and the apoptotic and proliferating indexes were calculated at predefined time points. Kolmogorov-Smirnov distances were considered to determine whether the percentage of ADC changes, and the apoptotic and proliferating indexes were normally distributed. An independent-samples t-test was used to analyze the difference between apoptotic and proliferating indexes in the two groups. Results： There was a statistically significant difference in proliferating index between the radiotherapy and control groups （mean proliferating index： 49.27% vs. 83.09%）, and there was a statistically significant difference in apoptotic index between the two groups （mean apoptotic index： 37.7% vs. 2.71%）. A significant positive correlation was found between the percentage of ADC changes of the viable tissue and apoptotic index. Pearson＇s correlation coefficient was 0.655 （P=0.015）. A significant negative correlation was found between the percentage of ADC changes of the viable tissue and ki-67 proliferation index. Pearson＇s correlation coefficient was 0.734 （P〈0.001）. Conclusions： Our results suggest that ADC proliferating indexes in colorectal carcinoma. value may be used in measurement of cell apoptotic and
文摘目的探析T2加权成像(T_(2)WI)联合扩散加权成像(DWI)用于直肠诊断及术前分期的效能及其相对表观扩散系数(rADC)、表观扩散系数(ADC)值与患者临床特征的相关性。方法选择疑似直肠癌患者212例,其中男性118例,女性94例;年龄42~83岁,平均年龄60.93岁;病程3个月~10年,平均病程5.64年。均行T_(2)WI联合DWI检查,以患者最终病理诊断结果为标准,计算T_(2)WI联合DWI对直肠癌的诊断效能,进行T、N分期诊断;以最终病理诊断结果为依据,计算其T、N分期诊断效能,并进行一致性检验;观察不同临床特征的患者间rADC、ADC值差异,绘制受试者工作特性(ROC)曲线,计算rADC、ADC值对直肠癌的诊断效能。结果术后病理诊断恶性172例,良性40例。T1期、T2期、T3期、T4期分别为8例、35例、31例、6例,N0期、N1期、N2期分别为37例、22例、21例。T_(2)WI联合DWI诊断直肠癌的准确度为92.45%,灵敏度为93.02%,特异度为90.00%;分期诊断中T1期、T2期、T3期、T4期诊断准确度为95.00%、93.75%、96.26%、95.00%,灵敏度为75.00%、94.12%、93.55%、71.43%,特异度为97.22%、95.65%、95.92%、97.26%。一致性检验显示T_(2)WI联合DWI与病理诊断结果的T分期诊断一致性较好(Kappa=0.863,P=0.000);N分期诊断中N0期、N1期、N2期诊断准确度分别为93.75%、90.00%、96.25%,灵敏度分别为94.59%、77.27%、95.24%,特异度分别为93.02%、94.83%、96.61%,一致性检验提示T_(2)WI联合DWI与病理诊断的N分期诊断一致性较好(Kappa=0.844,P=0.000);病变特征与rADC、ADC分析中,恶性病变rADC、ADC显著低于良性病变(0.84±0.09 vs 1.18±0.12、0.93±0.11 vs 1.39±0.11。P<0.05)。腺癌rADC、ADC显著高于黏液腺癌(0.89±0.11 vs 0.75±0.09、0.97±0.14 vs 0.83±0.11。P<0.05)。不同分化程度患者间rADC、ADC从高至低依次为高分化、中分化、低分化(rADC:0.95±0.16 vs 0.82±0.10 vs 0.72±0.08;ADC:1.05±0.17 vs 0.911±0.14 vs 0.81±0.09。P<0.05)。ADC诊断直肠癌AUC为0.987,灵敏度为92.44%,特异度为97.50%(P<0.001);rADC诊断结直肠癌AUC为0.941,灵敏度为92.44%,特异度为87.50%(P<0.001)。结论T_(2)WI联合DWI诊断直肠癌具有良好的诊断效能,且其术前T、N分期准确度高,与病理诊断一致性较好。rADC、ADC值在不同良恶性肿瘤、不同分化等级肿瘤、不同病理类型肿瘤间存显著差异,可作为良恶性及肿瘤分化程度的诊断依据。
文摘目的探讨DWI表观扩散系数(apparent diffusion coefficient,ADC)值对鉴别肺部良、恶性病变的价值及b值优化。方法对82例肺部结节或肿块行常规MRI和DWI检查,分别测量b值为300、500、800s/mm2时的病变ADC值。比较同一b值下良、恶性病变ADC值的差异。根据受试者工作特征曲线(r e c e i v e o p e r a t i n g characteristic curve,ROC)评价不同b值下ADC值鉴别肺部良恶性病变的诊断效能。结果 82个病例中恶性病变54例,良性病变28例。不同b值下恶性病变的平均AD均值均明显小于良性病变平均ADC值,差异均有统计学意义(P均<0.05)。b值取300、500、800s/mm2,AUC分别为0.806,0.838,0.826,均有诊断意义(AUC>0.5);其中b=500s/mm2时ADC值诊断效能最高,ADC阈值为1.492×10-3mm2/s,其敏感度、特异度、准确度分别为88.9%、78.6%、85.92%。结论 ADC值有助于鉴别肺部良恶病变,b值取500s/mm2时诊断效能较高。
