共查询到20条相似文献,搜索用时 31 毫秒
1.
Fifteen multiple sclerosis patients were examined by diffusion tensor imaging (DTI) to determine fractional anisotropy (FA) and apparent diffusion coefficient (ADC) in a superventricular volume of interest of 8×8×2 cm3 containing gray matter (GM) and white matter (WM) tissue. Point resolved spectroscopy 2D-chemical shift imaging of the same volume was performed without water suppression. The water contents and DTI parameters in 64 voxels of 2 cm3 were compared. The water content was increased in patients compared with controls (GM: 244±21 vs. 194±10 a.u.; WM: 245±32 vs. 190±11 a.u.), FA decreased (GM: 0.226±0.038 vs. 0.270±0.020; WM: 0.337±0.044 vs. 0.402±0.011) and ADC increased [GM: 1134±203 vs. 899±28 (×10−6 mm2/s); WM: 901±138 vs. 751±17 (×10−6 mm2/s)]. Correlations of water content with FA and ADC in WM were strong (r=−0.68, P<0.02; r=0.75; P<0.01, respectively); those in GM were weaker (r=−0.50, P<0.05; r=0.45, P<0.1, respectively). Likewise, FA and ADC were more strongly correlated in WM (r=−0.88; P<0.00001) than in GM (r=−0.69, P<0.01). The demonstrated relationship between DTI parameters and water content in multiple sclerosis patients suggests a potential for therapy monitoring in normal-appearing brain tissue. 相似文献
2.
Ohgiya Y Oka M Hiwatashi A Liu X Kakimoto N Westesson PL Ekholm SE 《European radiology》2007,17(10):2499-2504
Our purpose was to evaluate the ability of diffusion tensor imaging (DTI) to characterize cervical spinal cord white matter
(WM) in patients with multiple sclerosis (MS). DTI were obtained in 21 MS patients and 21 control subjects (CS). Regions of
interest (ROIs) were placed at C2/3, C3/4, and C4/5 within the right, left, and dorsal (WM) to calculate fractional anisotropy
(FA) and the apparent diffusion coefficient (ADC). Measurements in plaques and normal-appearing white matter (NAWM) of MS
patients were compared with mean FA and ADC of WM in CS. FA was significantly lower in all regions in MS patients than in
CS. ADC was significantly higher in all regions in MS patients than in CS except for in the dorsal WM at C2/3 and the bilateral
WM at C4/5. The mean FA was 0.441 for plaques and 0.542 for NAWM, as compared with 0.739 in CS. The mean ADC was 0.810 × 10−3 mm2/s for plaques and 0.722 × 10−3 mm2/s for NAWM, as compared with 0.640 ×10−3 mm2/s for CS. FA and ADC showed significant differences between plaques, NAWM and control WM(P < 0.01). 相似文献
3.
Introduction We prospectively compared the fractional anisotropy (FA) and mean diffusivity (MD) of the peritumoral edema of meningiomas
and metastatic brain tumors with diffusion-tensor magnetic resonance (MR) imaging.
Methods The study protocol was approved by the local ethics committee, and written informed consent was obtained. Preoperative diffusion-tensor
MR imaging was performed in 15 patients with meningiomas and 11 patients with metastatic brain tumors. Regions of interest
(ROI) were placed in the peritumoral edema and normal-appearing white matter (NAWM) of the contralateral hemisphere to measure
the FA and MD. The FA and MD ratios were calculated for each ROI in relation to the NAWM of the contralateral hemisphere.
Changes in peritumoral MD and FA, in terms of primary values and ratios, were compared using a two-sample t-test; P < 0.05 was taken as indicating statistical significance.
Results The mean MD values (×10−3 mm2/s) of the peritumoral edema for metastases and meningiomas, respectively, were 0.902 ± 0.057 and 0.820 ± 0.094, the mean
MD ratios were 220.3 ± 22.6 and 193.1 ± 23.4, the mean FA values were 0.146 ± 0.026 and 0.199 ± 0.052, and the mean FA ratios
were 32.3 ± 5.9 and 46.0 ± 12.1. All the values were significantly different between metastases and meningiomas (MD values
P = 0.016, MD ratios P = 0.006, FA values P = 0.005, FA ratios P = 0.002).
Conclusion The peritumoral edema of metastatic brain tumors and meningiomas show different MD and FA on diffusion-tensor MR imaging. 相似文献
4.
Quantitative diffusion-weighted MR imaging in the differential diagnosis of breast lesion 总被引:3,自引:0,他引:3
Marini C Iacconi C Giannelli M Cilotti A Moretti M Bartolozzi C 《European radiology》2007,17(10):2646-2655
The role of diffusion-weighted magnetic resonance imaging (DWI) to differentiate breast lesions in vivo was evaluated. Sixty
women (mean age, 53 years) with 81 breast lesions were enrolled. A coronal echo planar imaging (EPI) sequence sensitised to
diffusion (b value=1,000 s/mm2) was added to standard MR. The mean diffusivity (MD) was calculated. Differences in MD among cysts, benign lesions and malignant
lesions were evaluated, and the sensitivity and specificity of DWI to diagnose malignant and benign lesions were calculated.
The diagnosis was 18 cysts, 21 benign and 42 malignant nodules. MD values (mean±SD ×10−3 mm2/s) were (1.48±0.37) for benign lesions, (0.95±0.18) for malignant lesions and (2.25±0.26) for cysts. Different MD values
characterized different malignant breast lesion types. A MD threshold value of 1.1×10−3 mm2/s discriminated malignant breast lesions from benign lesions with a specificity of 81% and sensitivity of 80%. Choosing a
cut-off of 1.31×10−3 mm2/s (MD of malignant lesions -2 SD), the specificity would be 67% with a sensitivity of 100%. Thus, MD values, related to tumor
cellularity, provide reliable information to differentiate malignant breast lesions from benign ones. Quantitative DWI is
not time-consuming and can be easily inserted into standard clinical breast MR imaging protocols. 相似文献
5.
The purpose of this study was to compare relative values of manual unidimensional measurements (MD) and automated volumetry (AV) for longitudinal treatment response assessment in patients with pulmonary metastases. Fifty consecutive patients with pulmonary metastases and repeat chest multidetector-row CT (median interval=2 months) were independently assessed by two radiologists for treatment response using Response Evaluation Criteria In Solid Tumours (RECIST). Statistics included relative measurement errors (RME), intra-/interobserver correlations, limits of agreement (95% LoA), and kappa. A total of 202 metastases (median volume=182.22 mm3; range=3.16–5,195.13 mm3) were evaluated. RMEs were significantly higher for MD than for AV (intraobserver RME=2.34–3.73% and 0.15–0.22% for MD and AV respectively; P<0.05. Interobserver RME=3.53–3.76% and 0.22–0.29% for MD and AV respectively; P<0.05). Overall correlation was significantly better for AV than for MD (P<0.05). Intraobserver 95% LoAs were −1.85 to 1.75 mm for MD and −11.28 to 9.84 mm3 for AV. The interobserver 95% LoA were −1.46 to 1.92 mm for MD and −11.17 to 9.33 mm3 for AV. There was total intra-/interobserver agreement on response using AV (κ=1). MD intra- and interobserver agreements were 0.73–0.84 and 0.77–0.80 respectively. Of the 200 MD response ratings, 28 (14/50 patients) were discordant. Agreement using MD dropped significantly from total remission to progressive disease (P<0.05). We therefore conclude that AV allows for better reproducibility of response evaluation in pulmonary metastases and should be preferred to MD in these patients. 相似文献
6.
Ozgur Cakir Arzu Arslan Nagihan Inan Yonca Anık Tahsin Sarısoy Sevtap Gumustas Gur Akansel 《European journal of radiology》2013
Purpose
To evaluate the diagnostic efficiency of the diffusion parameters measured by conventional diffusion-weighted imaging (DWI) and diffusion tensor imaging (DTI) for discrimination of malignant breast lesions from benign lesions and the normal breast.Materials and methods
The study included 52 women with 55 breast lesions (30 malignant, 25 benign). DTI and DWI were performed complementary to dynamic contrast MRI at 3T. Apparent diffusion coefficient (ADC) of DWI, mean diffusivity (MD) and fractional anisotropy (FA) values of DTI were measured for lesions and contralateral breast parenchyma in each patient. We used b factors of 0, 50, 850, 1000 and 1500 s/mm2 for DWI and b 0 and 1000 s/mm2 for DTI. ADC, MD and FA values were compared between malignant and benign lesions, and the normal parenchyma by univariate and multivariate analyses.Results
Diffusion parameters showed no difference according to menopausal status in the normal breast. ADC and MD values of the malignant lesions were significantly lower than benign lesions and normal parenchyma (p = 0.001). The FA showed no statistical significance. With the cut-off values of ≤1.23 × 10−3 mm2/s (b 0–1000 s/mm2) and ≤1.12 × 10−3 mm2/s (b 0–1500 s/mm2), ADC showed 92.85% and 96.15% sensitivity; 72.22% and 73.52% PPV, respectively. With a cut-off value of ≤1.27 × 10−3 mm2/s (b 1000 s/mm2), MD was 100% sensitive with a PPV of 65.90%. Comparing the diagnostic performance of the parameters in DTI with DWI, we obtained similar efficiency of ADC with b values of 0,1000 and 0,1500 s/mm2 and MD with a b value of 0, 1000 s/mm2 (AUC = 0.82 ± 0.07).Conclusion
ADC of DWI and MD of DTI values provide significant discriminative factors for benign and malignant breast lesions. FA measurement was not discriminative. Supported with clinical and dynamic contrast MRI findings, DWI and DTI findings provide significant contribution to the final radiologic decision. 相似文献7.
Cerebral white matter is known to undergo degradation with aging, and diffusion tensor imaging (DTI) is capable of revealing
the white matter integrity. We assessed age-related changes of quantitative diffusivity parameters and fiber characteristics
within the fornix and the cingulum. Thirty-eight healthy subjects aged 18–88 years were examined at 3 Tesla using a 1.9-mm
isotropic DTI sequence. Quantitative fiber tracking was performed for 3D-segmentation of the fornix and the cingulum to determine
fractional anisotropy (FA), mean diffusivity (MD), eigenvalues (λ1, λ2, and λ3), number of fibers (NoF), and mean NoF/voxel (FpV). In the fornix, all diffusivity parameters (FA, MD, and eigenvalues) were
moderately correlated with age. Strong and moderate negative correlations for NoF and FpV were found, respectively. In the
cingulum, no correlation was observed between FA and age, and only weak correlations for the other quantitative parameters.
Differences in correlations between the fornix and the cingulum were significant for all diffusivity parameters and for NoF,
but not for FpV. The strongest relative changes per decade of age were found in the fornix: FA −2.1%, MD 4.2%, NoF −10.6%,
and FpV −4.6%. Our quantitative 3D fiber tracking approach shows that the cingulum is resistant to aging while the fornix
is not. 相似文献
8.
Gourtsoyianni S Papanikolaou N Yarmenitis S Maris T Karantanas A Gourtsoyiannis N 《European radiology》2008,18(3):486-492
The purpose of this study was to measure apparent diffusion coefficient values of normal liver parenchyma and focal liver
lesions utilizing a respiratory gated diffusion sequence with multiple b-values and to investigate whether apparent diffusion
coefficient (ADC) measurements may be utilized to characterize and differentiate between malignant and benign focal hepatic
lesions. Thirty-eight consecutive patients underwent MRI of the liver including diffusion-weighted imaging (DWI). A single-shot
echo planar imaging sequence was applied in coronal orientation with multiple b-values (0, 50, 500, 1,000 s/mm2) and respiratory gating. ADC values were recorded on corresponding maps utilizing region of interest measurements in patients
with benign (group A), malignant (group B) focal lesions and liver parenchyma (group C). Statistical analysis was applied
to check whether differences in mean ADC values were significant (p<0.05). No focal lesions were detected in 11 patients,
with a mean ADC value (CI 95%) of liver parenchyma 1.25×10−3 mm2/s (1.21×10−3 mm2/s−1.29×10−3 mm2/s). Differences in mean ADC of liver parenchyma between group A and B were not significant (p=0.054, 1.30×10−3 mm2/s and 1.31×10−3 mm2/s, respectively). Mean ADC value (95% CI) of 22 benign lesions found in 18 patients was 2.55×10−3 mm2/s (2.35×10−3 mm2/s−2.74×10−3 mm2/s), while the mean ADC value (95% CI) of 16 malignant lesions recorded in 9 patients was 1.04×10−3 mm2/s (0.9×10−3 mm2/s−1.17×10−3 mm2/s). The difference between mean ADC values of benign and malignant focal lesions was statistically significant (p<0.0001).
Respiratory gated diffusion-weighted imaging in the liver is technically feasible. Apparent diffusion coefficient measurements
can be useful in differentiating malignant from benign focal liver lesions. 相似文献
9.
Kinoshita T Moritani T Hiwatashi A Numaguchi Y Wang HZ Westesson PL Sugihara S Matsusue E Fujii S Ohama E Ogawa T 《Neuroradiology》2005,47(4):251-255
We retrospectively reviewed diffusion-weighted magnetic resonance images of 57 patients with a choroid plexus cyst diagnosed by contrast-enhanced T1-weighted imaging. All the cysts appeared to represent incidental findings. Thirty-eight of 57 patients had bilateral cysts and 19 had unilateral ones. On diffusion-weighted images, 78 of 95 cysts showed homogeneously high signal intensity, 12 showed focal high signal areas, and 5 had no portion with a high signal. The apparent diffusion coefficient of the high signal areas in the cysts was (1.46±0.14) ×10–3 mm2/s, intermediate between the apparent diffusion coefficients of cerebrospinal fluid and cerebral white matter, (3.15±0.67) ×10–3 and (0.79±0.22) ×10–3 mm2/s, respectively. Pathological correlation was available in one case, showing high signal intensity areas in the glomera of the choroid plexuses in the lateral ventricles on diffusion-weighted images corresponding to gelatinous cysts with highly proteinaceous content. 相似文献
10.
ObjectiveThis study sought to assess the feasibility of diffusion tensor imaging (DTI) to noninvasively evaluate histological grade and lymph node metastasis in patients with rectal carcinoma (RC).MethodsThirty-seven consecutive patients with histologically confirmed RC were examined by 1.5-T MRI. DTI was performed using a single-shot echo-planar imaging sequence with b values of 0 and 1000 s/mm2 and motion-probing gradients in nine noncollinear directions. Fractional anisotropy (FA), axial diffusivity (AD), mean diffusivity (MD), and radial diffusivity (RD) maps were compared with histopathological findings.ResultsThe FA values (0.357 ± 0.047) of the RCs were significantly lower than those of the normal rectal wall, muscle, prostate, and uterus (P < 0.001 for all), while the AD, MD, and RD values (1.221 ± 0.131, 0.804 ± 0.075, and 0.667 ± 0.057 × 10−3 mm2/s, respectively) were also significantly lower than their respective normal values (P < 0.001 for all). The FA, AD, MD, and RD values for RC additionally showed significant inverse correlations with histological grades (r = −0.781, r = −0.750, r = −0.718, and r = −0.682, respectively; P < 0.001 for all). Further, the FA (0.430 vs. 0.611), AD (1.246 vs. 1.608 × 10−3 mm2/s), MD (0.776 vs. 1.036 × 10−3 mm2/s), and RD (0.651 vs. 0.824 × 10−3 mm2/s) (P < 0.001 for all) of the metastatic and nonmetastatic lymph nodes were significantly different.ConclusionsDTI may be clinically useful for the noninvasive evaluation of histological grade and lymph node metastasis in patients with RC. 相似文献
11.
目的 探讨DTI技术诊断局灶性脑皮质发育不良(FCD)的价值.方法 回顾性分析12例FCD患者的临床、MRI及DTI等资料.DTI经过图像后处理,获得平均扩散系数(MD)和部分各向异性分数(FA)图及彩色编码张量图,于FCD的皮质下白质区及对侧相应皮质下白质区设置椭圆形ROI,测量每个ROI的MD及FA值.病灶侧与对侧MD、FA值的比较采用配对t检验.扩散张量纤维束示踪成像(DTT)以T_2 WI图像为参照,ROI设置同DTI,以ROI中的任一点作为种子点,获得通过该ROI区域的所有白质纤维束示踪图像.结果 12例患者MR平扫均显示局灶性脑皮质增厚及灰白质界限不清,其中7例显示皮质下白质稍长T_1、稍长T_2信号,2例皮质下白质萎缩,3例皮质下白质无明显异常.DTI分析显示FCD邻近皮质下白质与对侧比较FA值明显下降(患侧0.31±0.05,对侧0.42±0.08,t=-3.995,P<0.01),MD值明显上升[患侧(1.02±0.16)×10~(-3)mm~2/s,对侧(0.86±0.13)×10~(-3) mm~2/s,t=2.655,P<0.05],差异均有统计学意义.DTT显示10例FCD患者皮质下白质纤维束较对侧明确减少,2例较对侧可能减少,主要表现为皮质下白质纤维稀疏,与深部白质纤维间联系减少.结论 FCD除了导致脑皮质结构异常外,也影响局部皮质下白质纤维的发育,DTI是常规MR检查的重要补充. 相似文献
12.
Cosottini M Tavarelli C Del Bono L Doria G Giannelli M De Cori S Michelassi MC Bartolozzi C Murri L 《European radiology》2008,18(5):1024-1030
Progressive multifocal leukoencephalopathy (PML) is a severe demyelinating disease of the central nervous system due to JC
polyoma virus infection of oligodendrocytes. PML develops in patients with impaired T-cell function as occurs in HIV, malignancy
or immunosuppressive drugs users. Until now no imaging methods have been reported to correlate with clinical status. Diffusion-weighted
imaging (DWI) is a robust MRI tool in investigating white matter architecture and diseases. The aim of our work was to assess
diffusion abnormalities in focal white matter lesions in patients with PML and to correlate the lesion load measured with
conventional MRI and DWI to clinical variables. We evaluated eight patients with a biopsy or laboratory-supported diagnosis
of PML. All patients underwent MRI including conventional sequences (fluid attenuated inversion recovery-FLAIR) and DWI. Mean
diffusivity (MD) maps were used to quantify diffusion on white matter lesions. Global lesion load was calculated by manually
tracing lesions on FLAIR images, while total, central core and peripheral lesion loads were calculated by manually tracing
lesions on DWI images. Lesion load obtained with the conventional or DWI-based methods were correlated with clinical variables
such as disease duration, disease severity and survival. White matter focal lesions are characterized by a central core with
low signal on DWI images and high MD (1.853 × 10−3 mm2/s), surrounded by a rim of high signal intensity on DWI and lower MD (1.1 × 10−3 mm2/s). The MD value of normal-appearing white matter is higher although not statistically significant (0.783 × 10−3 mm2/s) with respect to control subjects (0.750 × 10−3 mm2/s). Inter-rater correlations of global lesion load between FLAIR (3.96%) and DWI (3.43%) was excellent (ICC =0.87). Global
lesion load on FLAIR and DWI correlates with disease duration and severity (respectively, p = 0.037, p = 0.0272 with Karnofsky
scale and p = 0.0338 with EDSS on FLAIR images; p = 0.043, p = 0.0296 with Karnofsky scale and p = 0.0365 with EDSS on DW
images). Central core lesion load on DWI correlates with disease duration and severity (respectively p = 0.043, p = 0.0103
with Karnofsky scale and p = 0.0112 with EDSS), while peripheral lesion load does not correlate with any clinical variable.
The global lesion load in PML correlates with disease duration and severity. DWI images, which can distinguish within lesions
a central core from a peripheral rim, reveal that a larger central core component correlates to a worsened clinical status
and longer disease duration. On the other hand the peripheral rim lesion load visualized on DWI images does not correlate
with clinical variables and does not achieve obtaining further prognostic information with respect to conventional imaging. 相似文献
13.
Clinical single-shot diffusion-weighted MRI of the human brain on a short-bore medium-field imager 总被引:1,自引:1,他引:0
Diffusion-weighted MRI (DWI) is becoming important for assessment of acute stroke. Until recently single-shot DWI required
expensive technology such as echo-planar imaging (EPI) available only at some research sites. A new medium-field (1.0 T) short-bore
MR imager has been developed with which DWI data sets can be acquired. We prospectively studied 169 patients on this 1.0 T
commercial system. After conventional imaging, DWI was performed with a single-shot multi-slice sequence with b values 0 an
900 s/mm2, and with the gradients switched in three directions. The apparent diffusion coefficients were calculated with online calculation
software. There were 50 patients with totally normal MRI, and 17 had strokes, these strokes were detected as areas of high
signal on the images at a maximal b value. There was a drop in the ADC in ischaemic regions: in subacute infarcts, the values
were between 0.41 and 0.531 × 10− 3 mm2/s. In old infarcts the ADC was 1.15 × 10− 3 mm2/s. Cerebrospinal fluid (CSF) gave low signal whereas areas in the brain had more intermediate intensities (CSF: 3.00; deep
white matter: 0.75, cortical grey matter: 0.80, basal ganglia (thalamus): 0.70 and cerebellar white matter: 0.65 × 10− 3 mm2/s. Anisotropy was detected as areas of restricted diffusion along the tracts. These preliminary data show that DWI can be
aquired successfully on a medium-field short-bore system. This should allow the technique to be implemented at more sites,
therefore facilitating the diagnosis of acute stroke and rendering early intervention feasible.
Received: 22 February 1999 Accepted: 27 April 1999 相似文献
14.
Ghada K. Gouhar Mona A. El-Hariri 《The Egyptian Journal of Radiology and Nuclear Medicine》2011,42(2):169-175
Purpose
To assess the feasibility of apparent diffusion coefficient (ADC) generated from diffusion weighted magnetic resonance imaging as a non invasive technique to differentiate tumor recurrence from radionecrosis in patients with laryngeal carcinoma.Materials and methods
Twenty one patients suspected of tumor recurrence underwent MRI including diffusion weighted imaging (DWI) (b 0 and 1000). ADC maps were generated and ADC values were measured at the lesion sites and the normal laryngeal tissues, and were compared with the histopathological results.Results
The mean ADC of tumor recurrence {1.04 ± 0.34 × 10−3 mm2/s (SD)} was significantly lower (p < 0.0001) than the mean ADC of the normal laryngeal tissues in the same patient (1.48 ± 0.099 × 10−3 mm2/s) while the mean ADC of radionecrosis (1.79 ± 0.41 × 10−3 mm2/s) was significantly higher (p < 0.04) than the mean ADC of the normal laryngeal tissues (1.49 ± 0.095 × 10−3 mm2). The mean ADC of tumor recurrence is significantly lower (p < 0.0001) than the mean ADC of radionecrosis with 1.16 × 10−3 mm2/s is the best cut value for differentiating tumor recurrence from radionecrosis.Conclusion
ADC can differentiate tumor recurrence from radionecrosis in laryngeal carcinoma. 相似文献15.
We evaluated the diagnostic ability of diffusion-weighted imaging for the differentiation between lymphomas and carcinomas
in the pharynx and between carcinomas with different histological types in the pharynx. T1-weighted, fat-suppressed T2-weighted,
and diffusion-weighted MR imaging was performed on 14 patients with pharyngeal lymphomas, 26 patients with carcinomas of the
pharynx, 5 patients with adenoidal hypertrophy, and 22 patients with normal tonsils. Apparent diffusion coefficients (ADCs)
were determined by using two b factors (500 and 1,000 s/mm2). The ADCs of lymphomas were significantly smaller (0.454 ± 0.075 × 10−3 mm2/s) than those of carcinomas (0.863 ± 0.238 × 10−3 mm2/s). The ADCs of poorly differentiated and undifferentiated carcinomas (0.691 ± 0.149 × 10−3 mm2/s) were significantly smaller than those of moderately differentiated and well-differentiated carcinomas (0.971 ± 0.221 × 10−3 mm2/s), but were significantly larger than those of lymphomas. When an ADC smaller than 0.560 × 10−3 mm2/s was used for predicting lymphomas, we obtained the highest accuracy of 96%, with 100% sensitivity and 94% specificity,
86% positive predictive value, and 100% negative predictive value. Therefore, ADC measurements effectively differentiate lymphomas
from carcinomas in the pharynx and could be a useful adjunct to biopsy-based development of treatment planning. 相似文献
16.
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. 相似文献
17.
Ulrike Löbel Jan Sedlacik Daniel Güllmar Werner A. Kaiser Jürgen R. Reichenbach Hans-Joachim Mentzel 《Neuroradiology》2009,51(4):253-263
Introduction The aim of our work was to investigate the process of myelination in healthy patients using the diffusion parameters apparent
diffusion coefficient (ADC), relative anisotropy (RA), fractional anisotropy (FA), and eigenvalues. Age-dependent changes
were assessed using the slope m of the fit functions that best described the data.
Materials and methods Seventy-two patients (3 weeks–19 years) without pathological magnetic resonance imaging findings were selected from all pediatric
patients scanned with diffusion tensor imaging over a 5-year period at our institution. ADC, RA, FA, and eigenvalue maps were
calculated and regions of interest were selected in anterior/posterior pons, genu/splenium of corpus callosum (CC), anterior/posterior
limb of internal capsule (IC), and white matter (WM) regions (frontal, temporal, parietal, occipital WM). Statistical analysis
was performed using Spearman correlation coefficient and regression analysis.
Results Mean values ranged 71.6 × 10−5 to 90.3 × 10−5 mm2/s (pons/parietal WM) for ADC, 0.32–0.94 (frontal WM/CC) for RA, and 0.36–0.81 (frontal WM/splenium) for FA. Logarithmic fit
functions best described the data. Strong age influences were observed for CC, pons, and parietal/frontal WM and changes were
significant for all three eigenvalues, most pronounced for perpendicular eigenvalues. Changes in RA and FA differed depending
on the structure anisotropy.
Conclusions Changes observed for ADC, RA, FA, and eigenvalues with age were consistent with previous findings. Changes detected for RA
and FA varied due to the different scaling of both parameters. We found that the use of the largely linear scaled RA adds
more valuable information for the assessment of age-dependent structural changes as compared to FA. Additionally, we report
normative values for the diffusion parameters studied. 相似文献
18.
Purpose
To evaluate the role of diffusion-weighted imaging (DWI) in differentiating the various causes of enlarged neck lymph nodes.Materials and methods
Thirty-four patients with enlarged neck lymph nodes clinically suggestive of malignancy underwent DWI with b values (0 and 1000). Apparent diffusion coefficient (ADC) maps are generated from DWI and ADC values were calculated for the enlarged lymph nodes and compared with histopathological results.Results
The patients were divided into nine patients with benign neck lymphadenopathy, 14 patients with metastasis from head and neck cancer and 11 patients with nodal lymphoma. The mean ADC of the benign neck lymph nodes (1.51 ± 0.36 × 10−3 mm2/s) was significantly higher than those of the metastatic (0.92 ± 0.13 × 10−3 mm2/s) and lymphomatous (0.74 ± 0.14 × 10−3 mm2/s) lymph nodes (p < 0.0001) and the mean ADC of the metastatic nodes was significantly higher than that of nodal lymphoma (p = 0.04). The mean ADC of well- and moderately differentiated metastasis (0.98 ± 0.14 × 10−3 mm2/s) was significantly higher than that of poorly differentiated metastasis (0.83 ± 0.06 × 10−3 mm2/s) (p = 0.03). The mean ADC of non-Hodgkin lymphoma (0.65 ± 0.06 × 10−3 mm2/s) was significantly lower than that of Hodgkin lymphoma (0.86 ± 0.11 × 10−3 mm2/s) (p = 0.004). The best threshold for differentiating malignant from benign lymph nodes was 1.15 × 10−3 mm2/s.Conclusion
DWI is a non-invasive technique that can help in the identification of the cause of enlarged neck lymph nodes. 相似文献19.
Introduction Distinguishing between vasogenic edema and reactive astrogliosis may be difficult in some instances. This study was performed
to test the hypothesis that diffusion-weighted (DW) imaging with apparent diffusion coefficient (ADC) maps can be used to
differentiate these two types of changes.
Methods The study population included 11 patients with perilesional vasogenic edema and 11 patients with gliosis examined with conventional
MR imaging and DW imaging. The signal intensities of conventional pulse sequences and ADC values were calculated in regions
of interest placed in the hyperintense edematous or gliotic regions and compared with those of normal-appearing white matter.
Signal intensity ratios and ADC values in gliosis were compared with those in vasogenic edema using the Mann-Whitney U-test.
Results While considerable overlap was present for signal intensity ratios on conventional MR images, areas of gliosis demonstrated
significantly higher ADC values (1.76 ± 0.09 × 10−3 mm2/s) than areas of vasogenic edema (1.35 ± 0.06 × 10−3 mm2/s; P < 0.0001) without overlap.
Conclusion ADC values are helpful in differentiating reactive gliosis from vasogenic edema. 相似文献
20.
Sherif Abdelfattah Khedr Mohamed Abdelfattah Hassaan Naglaa Mohamed Abdelrazek Amr yehia Sakr 《The Egyptian Journal of Radiology and Nuclear Medicine》2012