Apparent diffusion coefficient values of the normal uterus: Interindividual variations during menstrual cycle

Objectives

To assess the apparent diffusion coefficient (ADC) changes of the normal uterine zones among reproductive women during the menstrual cycle.

Methods

The study included 101 women of reproductive age, each with regular cycle and normal endometrium/myometrium, as proved on histopathology or MR imaging examination. Diffusion-weighted (DW) imaging was performed along the axial plane, using a single shot, multi-slice spin-echo planar diffusion pulse sequence and b-values of 0 and 800 s/mm². The mean and standard deviation of the ADC values of normal endometrium/myometrium were calculated for menstrual, proliferative and secretory phase. Analysis of variance followed by the least significant difference test was used for statistical analysis.

Results

The ADC values of the endometrium were different in the three phases of the menstrual cycle (menstrual phase: 1.25 ± 0.27; proliferative phase: 1.39 ± 0.20; secretory phase: 1.50 ± 0.18) (F: 9.64, p: 0.00). Statistical significant difference was observed among all groups (p < 0.05). The ADC values of the normal myometrium were different in the three phases of the menstrual cycle (menstrual phase: 1.91 ± 0.35; proliferative phase: 1.72 ± 0.27; secretory phase: 1.87 ± 0.28) (F: 3.60, p: 0.03). Statistical significant difference was observed between menstrual and proliferative phase and between proliferative and secretory phase (p < 0.05). No significant difference was noted between menstrual and secretory phase (p > 0.05).

Conclusions

A wide variation of ADC values of normal endometrium and myometrium is observed during different phases of the menstrual cycle.     

Diffusion-weighted MRI in cervical cancer

The purpose was to investigate the potential value of apparent diffusion coefficient (ADC) measurement with MRI in the assessment of cervix cancer. Diffusion-weighted MRI was performed in 47 patients with cervical carcinoma undergoing chemoradiation therapy and 26 normal controls on a 1.5-T system with a b-value of 600 s/mm². FIGO stage, tumor volume, nodal status, interstitial fluid pressure (IFP) and oxygen measurements were recorded. Response was defined as no visible tumor 3–6 months following completion of therapy. The average median ADC (mADC) of cervical carcinomas (1.09±0.20×10⁻³ mm²/s) was significantly lower than normal cervix (2.09±0.46×10⁻³ mm²/s) (P<0.001). There was no correlation between mADC, nodal status, tumor volume, IFP or oxygen measurements. mADC was significantly lower in FIGO stages T1b/T2a (0.986 × 10⁻³ mm²/s) compared to T2b (1.21×10⁻³ mm²/s) and T3/T4 (1.10×10⁻³ mm²/s) (P<0.001). In patients with squamous carcinomas the 90th percentile of ADC values was lower in responders than non-responders (P<0.05). Median ADC in cervix carcinoma is significantly lower compared to normal cervix. ADC may have predictive value in squamous tumors, but further long-term study will determine the ultimate clinical utility.     

绝经前女性正常宫颈组织的表观弥散系数值研究

目的探讨不同年龄段绝经前女性正常宫颈组织在不同生理周期的表观弥散系数值（apparent diffusion coef ficient,,ADC）变化。方法将82名健康女性按年龄段分成3组（A组27例,20～29岁;B组28例,30～39岁;C组27例,40～49岁）,采用3．0TMRl分别于增殖中期及分泌中期行2次盆腔MR检查,研究不同结构区、年龄段及生理周期的宫颈ADC值的变化。结果子宫3层结构的ADC值两两比较差异均有统计学意义（肌层最高,黏膜层居中,结合带最低）,宫颈黏膜层及结合带的ADC值在分泌中期均低于增殖中期,而肌层的ADC值在不同周期问差异不明显,宫颈每层结构在同一周期的各年龄组之间无明显差异,宫颈粘膜层在增殖中期的ADC值更为稳定。结论不同结构区及生理周期会对正常宫颈组织的ADC值产生影响,当利用ADC值探测早期宫颈癌、监测疗效及鉴别肿瘤早期复发时应考虑这些因素,绝经前女性应在增殖期行盆腔MR扫描。     

Apparent diffusion coefficient of diffusion weighted MRI in endometrial carcinoma-Relationship with local invasiveness

Objective

To evaluate the relationship between apparent diffusion coefficient (ADC) value and the local invasiveness of endometrial carcinoma.

Methods and materials

The MR imaging of seventy-three patients with endometrial carcinoma proved by post-operative pathology and sixty-four patients with healthy uteri were retrospectively reviewed. All MR examinations included axial T2WI and T1WI, sagittal T2WI and diffusion-weighted sequences (b = 0 and b = 1000 s/mm²). Tumor size, mean ADC value (ADCm) and quartile ADC (ADCq) were acquired on post-processing workstation using voxel-analysis software. Differences between the ADC values among three layers of normal uterine body and endometrial carcinomas were compared by ANOVA test. Groups were divided according to pathologic type, histologic grade, depth of myometrial infiltration, presence of cervical invasion and lymphovascular space invasion, and lymph node metastasis. Tumor size and ADC values were compared and analyzed.

Results

ADC values were different in three zones of uterine body (P < 0.001), with the lowest in junctional zone [(1.126 ± 0.190) × 10⁻³ mm²/s] and highest in outer myometrium [(1.496 ± 0.196) × 10⁻³ mm²/s]. Mean ADC value of endometrial carcinomas [(1.011 ± 0.121) × 10⁻³ mm²/s] was lower than the normal uterine body. Quartile ADC and tumor size were greater in groups with more invasive pathologic factors (P < 0.05). Deep myometrial infiltration, cervical invasion, lymphovascular space invasion and lymph node metastasis were more common as quartile ADC values and tumor sizes increased.

Conclusion

Mean ADC value was lower in endometrial carcinoma was lower than the normal uterus. Quartile ADC, representing the intra-tumor heterogeneity of water movement, had a profound relationship with invasiveness of endometrial carcinomas, while mean ADC value did not. ADC values may serve as a quantitative indicator to complement routine sequences.     

表观扩散系数直方图分析在肿瘤中的应用进展

表观扩散系数直方图分析是一种MR影像分析方法,与传统影像分析方法相比具有丰富的描述性参数,有助于评估肿瘤的整体异质性,在肿瘤诊断和治疗中发挥了越来越重要的作用。近年来,ADC直方图分析广泛用于肿瘤研究,特别是在鉴别肿瘤良恶性和评价肿瘤疗效方面。对ADC直方图分析方法及其在肿瘤鉴别诊断、术前预测组织病理学分级、评价疗效及预后方面应用的研究进展作一综述。     

正常子宫内膜和子宫内膜癌的扩散加权成像特点

目的探讨子宫内膜癌、子宫内膜不同周期及病理状态下的扩散加权成像的特点,研究表观扩散系数(ADC)及相对表观扩散系数(rADC)在子宫内膜癌的鉴别诊断应用价值。方法对29例子宫内膜癌,9例子宫内膜良性病变者和26例正常对照者行1.5T MRI检查并进行ADC值的测定(b值为800s/mm2)。闭孔内肌作参比部位,测量正常子宫内膜及内膜癌的rADC值,将不同组别ADC、rADC值相比较,进行统计学分析。结果子宫内膜癌ADC、rADC值分别为〔(0.96±0.22)×10-3 mm2/s、0.72±0.22〕,显著低于正常子宫内膜的ADC、rADC值〔(1.39±0.27)×10-3 mm2/s、1.02±0.22〕和子宫内膜良性病变ADC、rADC值〔(1.33±0.18)×10-3 mm2/s、1.02±0.28〕。萎缩期子宫内膜ADC、rADC值〔(1.62±0.37)×10-3 mm2/s、1.16±0.27〕显著高于增生期〔(1.29±0.14)×10-3 mm2/s、0.98±0.19〕和分泌期内膜〔(1.27±0.12)×10-3 mm2/s、0.94±0.12〕。结论 ADC有潜力鉴别子宫良性病变与子宫内膜癌,以闭孔内肌作为参比部位,所获得的rADC值可以很好的反映子宫内膜癌及正常子宫的扩散特征。     

The utility of diffusion-weighted MR imaging in cervical cancer

Purpose

To investigate the value of diffusion-weighted MR imaging (DWI) in detection of cervical cancer, and to determine the diagnostic accuracy of apparent diffusion coefficient (ADC) values for evaluating cervical cancer before and after chemoradiotherapy.

Materials and methods

Thirty-three patients with cervical squamous carcinoma and 20 patients with other pelvic abnormalities underwent diffusion-weighted imaging (DWI) in addition to routine MR imaging. The ADC values of normal cervical tissue, cervical area before and after chemoradiotherapy were measured and compared. Receiver operating characteristic (ROC) analysis was employed to investigate whether ADC values could help in discrimination among normal cervical tissue, cervical cancer before and after therapy, and to obtain the optimal ADC threshold value.

Results

Cervical cancer lesion demonstrated obviously hyperintensity on DWI images. The mean ADC value of cervical carcinoma (1.110 ± 0.175 × 10⁻³ mm²/s) was significantly lower than that of normal cervical tissue (1.593 ± 0.151 × 10⁻³ mm²/s) (P < 0.001). The mean ADC value of the cervical area in 22 patients treated by chemoradiotherapy (1.436 ± 0.129 × 10⁻³ mm²/s) was significantly higher than that before therapy (1.013 ± 0.094 × 10⁻³ mm²/s) (P < 0.001). The difference of ADC values between normal cervical tissue and cervical area after therapy was statistically significant (P < 0.01). The optimal ADC threshold values for distinguishing between normal cervical tissue and cervical carcinoma was 1.359 × 10⁻³ mm²/s, between cervical area before and after therapy was 1.255 × 10⁻³ mm²/s, between normal cervical tissue and cervical area after therapy was 1.525 × 10⁻³ mm²/s. The sensitivity and specificity were 100% and 84.8%, 95.5% and 100%, 70% and 81.8%, respectively.

Conclusion

DWI can be applied for the detection of cervical cancer because of its superior disease contrast with normal tissue. The measurement of the ADC values can be a useful tool to monitor the response to therapy for cervical carcinoma.     

背景抑制扩散加权成像(DWIBS)在宫颈癌诊断与分期中的价值

目的：探讨背景抑制扩散加权成像（DWIBS）在宫颈癌术前诊断与分期中的价值。方法：39例宫颈癌患者术前行常规MRI与背景抑制扩散加权成像（DWIBS）检查,所得图像经最大强度投影（MIP）重建,并反相显示。结果：宫颈癌、宫颈周围浸润灶及盆腔转移灶呈明显高信号。MRI常规序列检出宫颈癌38例,DWIBS检出39例;MRI常规序列检出24枚盆腔转移性淋巴结,DWIBS检出32枚。MRI常规序列宫颈癌分期符合率87.2%（34/39例）,MRI常规序列结合DWIBS符合率97.4%（38/39例）。结论：背景抑制扩散加权成像（DWIBS）能直观、敏感地显示宫颈癌及其转移灶,结合MRI常规序列有利于肿瘤分期,应作为宫颈癌重要辅助检查序列。     

Apparent diffusion coefficient for discriminating metastatic from non-metastatic lymph nodes in primary rectal cancer

Objective

To investigate whether the apparent diffusion coefficient (ADC) could be used to discriminate metastatic from non-metastatic lymph nodes (LNs) in patients with primary rectal cancer.

Methods

This study investigated 34 patients (male: 12, female: 22, mean: 62.7, range: 37–82) who underwent 1.5-T MRI with diffusion-weighted imaging (DWI) and subsequent surgical resection. A blinded radiologist measured the ADC value in each regional LN after referring to the T2-weighted images and DWI. The t-test was used to compare the mean ADC values of the metastatic and non-metastatic LNs. A ROC analysis was performed to calculate the diagnostic performance and obtain the optimal cut-off. The histopathological results were used as the reference standard.

Results

114 LNs (46 metastatic and 68 non-metastatic) were matched and analyzed. The mean ADC of the metastatic LNs was significantly lower than that of the non-metastatic LNs (0.9 ± 0.15 × 10⁻³ mm²/s; 1.1 ± 0.22 × 10⁻³ mm²/s, P < 0.0001). The area under the ROC curve was 0.734 (95% confidence interval, 0.644–0.812). When an ADC value of 1.0 × 10⁻³ mm²/s was used as the cut-off, a maximum accuracy of 72% was calculated (sensitivity, 78%; specificity, 67%).

Conclusions

Although ADC could be used to discriminate metastatic from non-metastatic LNs, the diagnostic accuracy is approximately 70%.     

Apparent diffusion coefficient values in peripheral and transition zones of the prostate: comparison between normal and malignant prostatic tissues and correlation with histologic grade

PURPOSE: To investigate the utility of apparent diffusion coefficient (ADC) values for discriminating tumor in patients with prostate cancer from normal prostatic tissues in healthy adult men, and to identify correlations between ADC and histologic grade of prostate cancer. MATERIALS AND METHODS: A total of 125 healthy male volunteers (mean age, 60 years; range, 50-86 years) and 90 prostate cancer patients (mean age, 71 years; range, 51-88 years) underwent diffusion-weighted imaging (DWI) of the prostate with a single-shot echo-planar imaging sequence using b-factors of 0 and 800 sec/mm2. ADC was measured from two locations in the peripheral zone (PZ) and two locations in the central gland (CG) in normal subjects, and tumor locations of PZ or transition zone (TZ) in patients with prostate cancer. RESULTS: Mean ADC values of tumor regions in both PZ (1.02+/-0.25x10(-3) mm2/sec) and TZ (0.94+/-0.21x10(-3) mm2/sec) were significantly lower than those in the corresponding normal regions (1.80+/-0.27x10(-3) mm2/sec and 1.34+/-0.14x10(-3) mm2/sec, respectively) (P<0.0001 each). Furthermore, a significant negative correlation was identified between ADC in PZ cancer and tumor Gleason score (rho=-0.497, P<0.0001). CONCLUSION: ADC values appear to provide acceptable diagnostic accuracy in both PZ and TZ.     

Pre-Treatment Diffusion-Weighted MR Imaging for Predicting Tumor Recurrence in Uterine Cervical Cancer Treated with Concurrent Chemoradiation: Value of Histogram Analysis of Apparent Diffusion Coefficients

Objective

To evaluate the value of apparent diffusion coefficient (ADC) histogram analysis for predicting tumor recurrence in patients with uterine cervical cancer treated with chemoradiation therapy (CRT).

Materials and Methods

Our institutional review board approved this retrospective study and waived informed consent from each patient. Forty-two patients (mean age, 56 ± 14 years) with biopsy-proven uterine cervical squamous cell carcinoma who underwent both pre-treatment pelvic magnetic resonance imaging with a 3.0 T magnetic resonance scanner and concurrent CRT were included. All patients were followed-up for more than 6 months (mean, 36.4 ± 11.9 months; range 9.0-52.8 months) after completion of CRT. Baseline ADC parameters (mean ADC, 25th percentile, 50th percentile, and 75th percentile ADC values) of tumors were calculated and compared between the recurrence and no recurrence groups.

Results

In the recurrence group, the mean ADC and 75th percentile ADC values of tumors were significantly higher than those of the no recurrence group (p = 0.043 and p = 0.008, respectively). In multivariate analysis, the 75th percentile ADC value of tumors was a significant predictor for tumor recurrence (p = 0.009; hazard ratio, 1.319). When the cut-off value of the 75th percentile ADC (0.936 × 10^-3 mm²/sec) was used, the overall recurrence free survival rate above the cut-off value was significantly lower than that below the cut-off value (51.9% vs. 91.7%, p = 0.003, log-rank test).

Conclusion

Pre-CRT ADC histogram analysis may serve as a biomarker for predicting tumor recurrence in patients with uterine cervical cancer treated with CRT.     

使用ADC值评估正常及退变腰椎间盘的初步研究

目的:使用平均表观弥散系数(apparent diffusion coefficient,ADC)值可反映成人腰椎间盘中的水分子运动,探讨椎间盘ADC值和MR表现是否有相关性。方法:对28例患者及22名志愿者进行腰椎的MR弥散加权成像,测量每个椎间盘的ADC值。根据矢状位T2WI的MR表现,将椎间盘分为正常组和退变组。对比正常和退变椎间盘的平均ADC值,并对部位进行相关研究。结果:总计50名参与者中除3例因伪影明显未行ADC值测量外,余47例均成功行DWI及ADC值测量。正常和退变椎间盘的平均ADC值分别为2.32±0.54(×10-3mm2/s)和1.87±0.42(×10-3mm2/s)。ADC值与部位有明显的统计学相关性。结论:对比正常腰椎间盘,退变椎间盘的ADC值有明显的减低。且邻近骶尾部的椎间盘较头侧椎间盘的ADC值低。     

Age-related changes of the diffusion tensor imaging parameters of the normal cervical spinal cord

BackgroundThe diffusion tensor imaging (DTI) parameters of the cervical spinal cord (CSC) changes with age. However, previous studies only examined specific CSC areas.ObjectivesTo analyze the DTI parameters in all intervertebral space levels of the whole normal CSC and to study the impact of age on these parameters in a Chinese population.MethodsThirty-six healthy subjects aged 20–77 years were recruited. DTI parameters were calculated for gray matter (GM) and white matter (WM) funiculi in all the CSC intervertebral spaces (C1/2-C6/7). Age-related changes of DTI parameters were analyzed for the GM and WM funiculi.ResultsFractional anisotropy (FA) and mean diffusivity (MD) were lower in GM than in WM. MD and FA values were lower in the WM in the lower CSC compared with the upper CSC (all P < 0.05), but no difference was observed in GM. In ventral funiculi, MD increased with age, while FA decreased (all P < 0.001). In lateral and dorsal funiculi, MD and FA decreased with age (all P < 0.001). In GM, MD and FA decreased with age (all P < 0.001). Significant age-related changes were observed in FA and MD from GM and WM funiculi. FA was correlated with age in all funiculi (ventral: r = −0.733; lateral: r = −0.468; dorsal: r = −0.607; GM: r = −0.724; all P < 0.01).ConclusionImportant changes in MD and FA were observed with advancing age at all levels of CSC in Chinese patients. DTI parameters may be useful to assess CSC pathology, but the influence of age and segments need to be taken into account in diagnosis.     

Regional diffusion changes of cerebral grey matter during normal aging—A fluid-inversion prepared diffusion imaging study

Background and purpose

Although diffusion characteristics of white matter (WM) and its aging effects have been well described in the literature, diffusion characteristics of grey matter (GM), especially the cortical GM, have not been fully evaluated. In the present study, we used the fluid-inversion prepared diffusion imaging (FLIPD) technique to determine if there are age-related water diffusivity changes in GM.

Materials and methods

120 healthy volunteers were recruited for our study. They were divided into three age groups: group one (20-39 years old), group two (40-59 years old) and group three (60 years or older). All patients were evaluated with MRI using FLIPD at 3.0 T. Apparent diffusion coefficient (ADC) values of the frontal GM, cingulate cortex and thalami were determined bilaterally by region-of-interest analysis.

Results

Group three had significantly higher ADC values in both thalami and the left frontal GM compared to group two or group one. No ADC value difference was found among the three groups in the right frontal GM and bilateral cingulate cortex. There was a significant positive correlation between individual ADC values and age in both thalami and left frontal GM. For the cingulate cortex and the right frontal GM, ADC values did not correlate significantly with advancing age.

Conclusion

Statistically significant age-related diffusion changes were observed in both thalami and the left frontal cortex. The data reported here may serve as a reference for future studies.     

子宫内膜癌的DWI成像特征及其与PCNA、Ki-67表达相关性研究

目的:本研究拟利用PCNA及Ki-67的特殊标记物功能,通过测定不同恶性程度子宫内膜癌组织中的PCNA和Ki-67不同表达程度,及其与DWI图像ADC值及rADC值的相关性研究,探讨应用DWI对于子宫内膜癌恶性程度分子水平定量研究的鉴别诊断价值。方法:对23例子宫内膜癌患者在术前行常规MRI检查并进行ADC值的测定(b值为800s/mm2)。闭孔内肌作参比部位,测量内膜癌的rADC值。所有病例均经病理证实,包括高分化8例,中分化10例,低分化5例。用免疫组织化学染色方法(SP法)检测23例子宫内膜癌标本中PCNA及Ki-67的表达情况。结果:子宫内膜癌随着肿瘤恶性分化程度降低,各组的ADC及rADC值存在下降趋势。低分化组ADC、rADC值〔(0.79±0.14)×10-3mm2/s、0.55±0.11〕显著低于高分化组〔(1.05±0.18)×10-3 mm2/s、0.80±0.22〕,中分化组〔(0.89±0.15)×10-3 mm2/s、0.66±0.16〕ADC、rADC值与低分化组及高分化组相比均无统计学差异。子宫内膜癌PCNA、Ki-67表达程度与肿瘤ADC、rADC值呈显著性负相关。结论:子宫内膜癌DWI成像ADC、rADC值的测量有助于评价并鉴别肿瘤不同病理级别并有潜力作为评价肿瘤增殖程度的无创性方法。子宫内膜癌PCNA、Ki-67表达程度与ADC、rADC值显著性负相关,提示核磁共振扩散加权成像有潜力从分子水平反映细胞增殖程度。     

不同b值下前列腺外周带癌灶ADC值的初步定量分析

目的:探讨DWI在不同b值下前列腺外周带癌灶ADC值的参考值范围。方法:对28例前列腺外周带癌(PCa)的DWI在b值分别为300、600、8001、000 s/mm2时所得前列腺外周带癌灶和正常外周带ADC值进行定量分析。结果:b值分别为300、600、800、1000s/mm2下外周带癌灶的平均ADC值分别为(1.12±0.24)×10-3、(0.95±0.19)×10-3(、0.88±0.14)×10-3(、0.81±0.17)×10-3mm2/s,外周带非癌区平均ADC值分别为(1.93±0.39)×10-3、(1.78±0.23)×10-3、(1.61±0.21)×10-3、(1.53±0.21)mm2/s,同b值下2者比较有统计学意义(P<0.05)。b值分别为300、600、8001、000 s/mm2下外周带癌灶ADC值参考范围分别为(0.63～1.61)×10-3(、0.56～1.34)×10-3(、0.59～1.17)、(0.46～1.16)×10-3mm2/s。结论:前列腺外周带癌区和非癌区ADC值随b值变化而变化,通过ADC值测量可以定量分析前列腺外周带癌,提高前列腺癌诊断的准确率。     

The utility of diffusion-weighted MR imaging for differentiating uterine sarcomas from benign leiomyomas

The usefulness of diffusion-weighted (DW) magnetic resonance (MR) imaging for the diagnosis of uterine sarcomas was investigated, as well as whether DW images and quantitative measurement of apparent diffusion coefficient (ADC) values can facilitate differentiating uterine sarcomas from benign leiomyomas. MR images including DW images were obtained in 43 surgically treated patients with 58 myometrial tumors, including seven uterine sarcomas (five leiomyosarcomas and two endometrial stromal sarcomas) and 51 benign leiomyomas (43 ordinary leiomyomas, two cellular leiomyomas and six degenerated leiomyomas). Qualitative analysis of non-enhanced and postcontrast MR images and DW images and quantitative measurement of ADC values were performed for each myometrial tumor. Both uterine sarcomas and cellular leiomyomas exhibited high signal intensity on DW images, whereas ordinary leiomyomas and most degenerated leiomyomas showed low signal intensity. The mean ADC value (10⁻³ mm²/s) of sarcomas was 1.17 ± 0.15, which was lower than those of the normal myometrium (1.62 ± 0.11) and degenerated leiomyomas (1.70 ± 0.11) without any overlap; however, they were overlapped with those of ordinary leiomyomas and cellular leiomyomas. In addition to morphological features on nonenhanced and postcontrast MR sequences, DW imaging and ADC measurement may have a potential ability to differentiate uterine sarcomas from benign leiomyomas.     

Apparent diffusion coefficient in pancreatic cancer: characterization and histopathological correlations

PURPOSE: To clarify the components primarily responsible for diffusion abnormalities in pancreatic cancerous tissue. MATERIALS AND METHODS: Subjects comprised 10 patients with surgically confirmed pancreatic cancer. Diffusion-weighted (DW) echo-planar imaging (b value = 0, 500 s/mm(2)) was employed to calculate the apparent diffusion coefficient (ADC). ADC values of cancer and noncancerous tissue were calculated. Furthermore, ADC values of the cancer were compared with histopathological results. RESULTS: The mean (+/-standard deviation) ADC value was significantly lower for tumor (1.27 +/- 0.52 x 10(-3) mm(2)/s) than for noncancerous tissue (1.90 +/- 0.41 x 10(-3) mm(2)/s, P < 0.05). Histopathological examination showed similar proportions of fibrotic area, cellular component, necrosis, and mucin in each case. Regarding the density of fibrosis in cancer, three cases were classified in the loose fibrosis group and the remaining seven cases were classified in the dense fibrosis group. The mean ADC value was significantly higher in the loose fibrosis group (1.88 +/- 0.39 x 10(-3) mm(2)/s) than in the dense fibrosis group (1.01 +/- 0.29 x 10(-3) mm(2)/s, P < 0.05). In quantitative analysis, ADC correlated well with the proportion of collagenous fibers (r = -0.87, P < 0.05). CONCLUSION: Collagenous fibers may be responsible for diffusion abnormalities in pancreatic cancer.     

MR扩散加权成像在宫颈癌诊断和分期中的应用价值

目的 探讨磁共振扩散加权成像（DWI）在宫颈癌诊断的敏感性、分期的准确性及盆腔淋巴结转移的检出率和定性准确率中的应用价值.方法 回顾性分析经术后病理证实的98例宫颈癌患者的影像资料,比较DWI联合常规MRI序列与单纯常规MRI序列在宫颈癌诊断、分期及盆腔淋巴结转移方面的差异.结果 DWI联合常规MRI序列对Ⅰb期的漏诊率（1/20）低于单纯常规MRI序列漏诊率（5/20）.DWI联合常规MRI序列对Ⅱb期分期准确率（21/23）高于单纯常规MRI序列准确率（14/23）;其余各期分期,两者无明显差异.DWI联合常规MRI序列对盆腔淋巴结转移的检出率（135/148）和定性准确率（76/82）均高于单纯常规MRI序列的检出率（101/148）和定性准确率（56/82）.结论 相对于常规MRI序列,DWI联合常规MRI序列对宫颈癌的诊断更敏感,Ⅱb期分期更准确,盆腔淋巴结检出率和定性准确率更可靠.