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1.
Raya JG Dietrich O Birkenmaier C Sommer J Reiser MF Baur-Melnyk A 《European radiology》2007,17(11):2872-2879
The feasibility of a diffusion-weighted single-shot fast-spin-echo sequence for the diagnostic work-up of bone marrow diseases
was assessed. Twenty healthy controls and 16 patients with various bone marrow pathologies of the spine (bone marrow edema,
tumor and inflammation) were examined with a diffusion-weighted single-shot sequence based on a modified rapid acquisition
with relaxation enhancement (mRARE) technique; four diffusion weightings (b-values: 50, 250, 500 and 750 s/mm2) in three orthogonal orientations were applied. Apparent diffusion coefficients (ADCs) were determined in the bone marrow
and in the intervertebral discs of healthy volunteers and in diseased bone marrow. Ten of the 20 volunteers were repeatedly
scanned within 30 min to examine short-time reproducibility. Spatial reproducibility was assessed by measuring ADCs in two
different slices including the same lesion in 12 patients. The ADCs of the lesions exhibited significantly higher values,
(1.27 ± 0.32)×10−3 mm2/s, compared with healthy bone marrow, (0.21 ± 0.10)×10−3 mm2/s. Short-time and spatial reproducibility had a mean coefficient of variation of 2.1% and 6.4%, respectively. The diffusion-weighted
mRARE sequence provides a reliable tool for determining quantitative ADCs in vertebral bone marrow with adequate image quality. 相似文献
2.
The aim of this study was to evaluate the ability of diffusion-weighted MRI in differentiating transudative from exudative pleural effusions. Fifty-seven patients with pleural effusion were studied. Diffusion-weighted imaging (DWI) was performed with an echo-planar imaging (EPI) sequence (b values 0, 1000 s/mm2) in 52 patients. The apparent diffusion coefficient (ADC) values were reconstructed from three different regions. Subsequently, thoracentesis was performed and the pleural fluid was analyzed. Laboratory results revealed 20 transudative and 32 exudative effusions. Transudates had a mean ADC value of 3.42±0.76×10–3 mm2/s. Exudates had a mean ADC value of 3.18±1.82×10–3 mm2/s. The optimum cutoff point for ADC values was 3.38×10–3 mm2/s with a sensitivity of 90.6% and specificity of 85%. A significant negative correlation was seen between ADC values and pleural fluid protein, albumin concentrations and lactate dehydrogenase (LDH) measurements (r=–0.69, –0.66, and –0.46, respectively; p<0.01). The positive predictive value, negative predictive value, and diagnostic accuracy of ADC values were determined to be 90.6, 85, and 88.5%, respectively. The application of diffusion gradients to analyze pleural fluid may be an alternative to the thoracentesis. Non-invasive characterization of a pleural effusion by means of DWI with single-shot EPI technique may obviate the need for thoracentesis with its associated patient morbidity. 相似文献
3.
Differentiation of clinically benign and malignant breast lesions using diffusion-weighted imaging 总被引:34,自引:0,他引:34
Guo Y Cai YQ Cai ZL Gao YG An NY Ma L Mahankali S Gao JH 《Journal of magnetic resonance imaging : JMRI》2002,16(2):172-178
PURPOSE: To evaluate the value of diffusion-weighted imaging (DWI) in distinguishing between benign and malignant breast lesions. MATERIALS AND METHODS: Fifty-two female subjects (mean age = 58 years, age range = 25-75 years) with histopathologically proven breast lesions underwent DWI of the breasts with a single-shot echo-planar imaging (EPI) sequence using large b values. The computed mean apparent diffusion coefficients (ADCs) of the breast lesions and cell density were then correlated. RESULTS: The ADCs varied substantially between benign breast lesions ((1.57 +/- 0.23) x 10(-3) mm(2)/second) and malignant breast lesions ((0.97 +/- 0.20) x 10(-3) mm(2)/second). In addition, the mean ADCs of the breast lesions correlated well with tumor cellularity (P < 0.01, r = -0.542). CONCLUSION: The ADC would be an effective parameter in distinguishing between malignant and benign breast lesions. Further, tumor cellularity has a significant influence on the ADCs obtained in both benign and malignant breast tumors. 相似文献
4.
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
5.
Hyungjin Kim Jeong Min Lee Jeong Hee Yoon Jin-Young Jang Sun-Whe Kim Ji Kon Ryu Stephan Kannengiesser Joon Koo Han Byung Ihn Choi 《Korean journal of radiology》2015,16(6):1216-1225
ObjectiveTo investigate the image quality (IQ) and apparent diffusion coefficient (ADC) of reduced field-of-view (FOV) di-ffusion-weighted imaging (DWI) of pancreas in comparison with full FOV DWI.ResultsOn qualitative analysis, reduced FOV DWI showed better anatomic structure visualization (2.76 ± 0.79 at b = 0 s/mm2 and 2.81 ± 0.64 at b = 400 s/mm2), lesion conspicuity (3.11 ± 0.99 at b = 0 s/mm2 and 3.15 ± 0.79 at b = 400 s/mm2), IQ score (8.51 ± 2.05 at b = 0 s/mm2 and 8.79 ± 1.60 at b = 400 s/mm2), and higher clinical utility (3.41 ± 0.64), as compared to full FOV DWI (anatomic structure, 2.18 ± 0.59 at b = 0 s/mm2 and 2.56 ± 0.47 at b = 500 s/mm2; lesion conspicuity, 2.55 ± 1.07 at b = 0 s/mm2 and 2.89 ± 0.86 at b = 500 s/mm2; IQ score, 7.13 ± 1.83 at b = 0 s/mm2 and 8.17 ± 1.31 at b = 500 s/mm2; clinical utility, 3.14 ± 0.70) (p < 0.05). Artifacts were significantly improved on reduced FOV DWI (2.65 ± 0.68) at b = 0 s/mm2 (full FOV DWI, 2.41 ± 0.63) (p < 0.001). On quantitative analysis, there were no significant differences between the 2 DWI sequences in ADCs of various pancreatic lesions and parenchyma (p > 0.05). ADCs of adenocarcinomas (1.061 × 10-3 mm2/s ± 0.133 at reduced FOV and 1.079 × 10-3 mm2/s ± 0.135 at full FOV) and neuroendocrine tumors (0.983 × 10-3 mm2/s ± 0.152 at reduced FOV and 1.004 × 10-3 mm2/s ± 0.153 at full FOV) were significantly lower than those of parenchyma (1.191 × 10-3 mm2/s ± 0.125 at reduced FOV and 1.218 × 10-3 mm2/s ± 0.103 at full FOV) (p < 0.05).ConclusionReduced FOV DWI of the pancreas provides better overall IQ including better anatomic detail, lesion conspicuity and subjective clinical utility. 相似文献
6.
Kolja M. Thierfelder Wieland H. Sommer Olaf Dietrich Felix G. Meinel Daniel Theisen Philipp M. Paprottka Frederik F. Strobl Josef Pfeuffer Maximilian F. Reiser Konstantin Nikolaou 《European journal of radiology》2014
Objectives
To find out whether the use of accelerated 2D-selective parallel-transmit excitation MRI for diffusion-weighted EPI (pTX-EPI) offers advantages over conventional single-shot EPI (c-EPI) with respect to different aspects of image quality in the MRI of the pancreas.Materials and methods
The MRI examinations of 33 consecutive patients were evaluated in this prospective and IRB-approved study. PTX-EPI was performed with a reduced (zoomed) FOV of 230 × 118 mm2. The 2D-RF pulse of pTX-EPI was accelerated, i.e. shortened by a factor of 1.7 (pTX-acceleration factor). C-EPI used a full-FOV of 380 × 285 mm2. In a qualitative analysis, two experienced readers evaluated 3 different aspects of image quality on 3- to 5-point Likert scales. Additionally, apparent diffusion coefficients (ADCs) were determined in both c-EPI and pTX-EPI in normal-appearing pancreatic tissue using regions of interests (ROIs). Mean ADC values and standard deviations were compared between the two techniques.Results
The reduced-FOV pTX-EPI was superior to c-EPI with respect to overall image quality (p < 0.0001) and identifiability of the pancreatic ducts (p < 0.01). Artifacts were significantly less severe in pTX-EPI (p < 0.01). The mean ADC values of c-EPI (1.29 ± 0.19 × 10−3 mm2/s) and pTX-EPI (1.27 ± 0.17 × 10−3 mm2/s) did not differ significantly between the two techniques (p = 0.44). The variation within the ROIs as measured by the standard deviation was significantly lower in pTX-EPI (0.095 × 10−3 mm2/s) than in c-EPI (0.135 × 10−3 mm2/s), p < 0.05.Conclusions
PTX-accelerated EPI with spatially-selective excitation and reduced FOV leads to substantial improvements in DWI of the pancreas with respect to different aspects of image quality without significantly influencing the ADC values. 相似文献7.
Purpose
The purpose of this study is to compare BLADE diffusion-weighted imaging (DWI) with single-shot echo planar imaging (EPI) DWI on the aspects of feasibility of imaging the sellar region and image quality.Methods
A total of 3 healthy volunteers and 52 patients with suspected lesions in the sellar region were included in this prospective intra-individual study. All exams were performed at 3.0 T with a BLADE DWI sequence and a standard single-shot EP-DWI sequence. Phantom measurements were performed to measure the objective signal-to-noise ratio (SNR). Two radiologists rated the image quality according to the visualisation of the internal carotid arteries, optic chiasm, pituitary stalk, pituitary gland and lesion, and the overall image quality. One radiologist measured lesion sizes for detecting their relationship with the image score.Results
The SNR in BLADE DWI sequence showed no significant difference from the single-shot EPI sequence (P > 0.05). All of the assessed regions received higher scores in BLADE DWI images than single-shot EP-DWI. 相似文献8.
Takao Taniguchi Hisato Kobayashi Koji Nishikawa Etsushi Iida Yoshihiro Michigami Emiko Morimoto Rikiya Yamashita Ken Miyagi Motozumi Okamoto 《Japanese journal of radiology》2009,27(3):138-142
Purpose The aim of this study was to investigate the usefulness of diffusion-weighted magnetic resonance imaging (DWI MRI) for the
diagnosis and evaluation of autoimmune pancreatitis (AIP).
Materials and methods A total of 4 consecutive patients with AIP, 5 patients with chronic alcoholic pancreatitis (CP), and 13 patients without pancreatic
disease (controls) were studied. DWI was performed in the axial plane with spin-echo echo-planar imaging single-shot sequence.
Apparent diffusion coefficients (ADCs) were measured in circular regions of interest in the pancreas. In AIP patients, abdominal
MRI was performed before, and 2–4 weeks after steroid treatment. Follow-up study was performed chronologically for up to 11
months in two patients. The correlation between ADCs of the pancreas and the immunoglobulin G4 (IgG4) index (serum IgG4 value/serum
IgG4 value before steroid treatment) was evaluated.
Results In the AIP patients, DWI of the pancreas showed high signal intensity, and the ADCs of the pancreas (mean ± SD: 0.97 ± 0.18
× 10−3 mm2/s) were significantly lower than those in patients with CP (1.45 ± 0.10 × 10−3 mm2/s) or the controls (1.45 ± 0.16 × 10−3 mm2/s) (Mann-Whitney U-test, P < 0.05). In one AIP patient with focal swelling of the pancreas head that appeared to be a mass, DWI showed high signal intensity
throughout the pancreas, indicating diffuse involvement. The ADCs of the pancreas and IgG4 index were significantly inversely
correlated (Spearman’s rank correlation coefficient, r
s = −0.80, P < 0.05).
Conclusion Autoimmune pancreatitis showed high signal intensity on DWI, which improved after steroid treatment. ADCs reflected disease
activity. Thus, diffusion-weighted MRI might be useful for diagnosing AIP, determining the affected area, and evaluating the
effect of treatment.
T. Taniguchi and H. Kobayashi contributed equally to this study 相似文献
9.
Leonardo K Bittencourt Ulrike I Attenberger Daniel Lima Ralph Strecker Andre de Oliveira Stefan O Schoenberg Emerson L Gasparetto Daniel Hausmann 《World journal of radiology》2014,6(6):374-380
AIM: To evaluate the impact of computed b = 1400 s/mm2 (C-b1400) vs measured b = 1400 s/mm2 (M-b1400) diffusion-weighted images (DWI) on lesion detection rate, image quality and quality of lesion demarcation using a modern 3T-MR system based on a small-field-of-view sequence (sFOV).METHODS: Thirty patients (PSA: 9.5 ± 8.7 ng/mL; 68 ± 12 years) referred for magnetic resonance imaging (MRI) of the prostate were enrolled in this study. All measurements were performed on a 3T MR system. For DWI, a single-shot EPI diffusion sequence (b = 0, 100, 400, 800 s/mm²) was utilized. C-b1400 was calculated voxelwise from the ADC and diffusion images. Additionally, M-b1400 was acquired for evaluation and comparison. Lesion detection rate and maximum lesion diameters were obtained and compared. Image quality and quality of lesion demarcation were rated according to a 5-point Likert-type scale. Ratios of lesion-to-bladder as well as prostate-to-bladder signal intensity (SI) were calculated to estimate the signal-to-noise-ratio (SNR).RESULTS: Twenty-four lesions were detected on M-b1400 images and compared to C-b1400 images. C-b1400 detected three additional cancer suspicious lesions. Overall image quality was rated significantly better and SI ratios were significantly higher on C-b1400 (2.3 ± 0.8 vs 3.1 ± 1.0, P < 0.001; 5.6 ± 1.8 vs 2.8 ± 0.9, P < 0.001). Comparison of lesion size showed no significant differences between C- and M-b1400 (P = 0.22).CONCLUSION: Combination of a high b-value extrapolation and sFOV may contribute to increase diagnostic accuracy of DWI without an increase of acquisition time, which may be useful to guide targeted prostate biopsies and to improve quality of multiparametric MRI (mMRI) especially under economical aspects in a private practice setting. 相似文献
10.
Aine Sakurada Taro Takahara Thomas C. Kwee Tomohiro Yamashita Seiji Nasu Tomohiko Horie Marc Van Cauteren Yutaka Imai 《European radiology》2009,19(6):1461-1469
The purpose of this study was to assess the value of diffusion-weighted magnetic resonance imaging (DWI) in detecting esophageal
cancer and assessing lymph-node status, compared with histopathological results. DWI was prospectively performed in 24 consecutive
patients with esophageal cancer, using the diffusion-weighted whole-body imaging with background body signal suppression (DWIBS)
sequence. DWIBS images were fused with T2-weighted images, and independently and blindly evaluated by three board-certified
radiologists, regarding primary tumor detectability and lymph-node status. Apparent diffusion coefficients (ADCs) of the primary
tumor and lymph nodes were also measured. Average primary tumor detection rate was 49.4%, average patient-based sensitivity
and specificity for the detection of lymph-node metastasis were 77.8 and 55.6%, and average lymph-node group-based sensitivity
and specificity were 39.4 and 92.6%. There were no interobserver differences among the three readers (P < 0.0001). Mean ADC of detected primary tumors was 1.26 ± 0.29×10−3 mm2/s. Mean ADC of metastatic lymph nodes (1.46 ± 0.35×10−3 mm2/s) was significantly higher (P < 0.0001) than that of nonmetastatic lymph nodes (1.15 ± 0.24 mm2/s), but ADCs of both groups overlapped. In conclusion, this study suggests that DWI only has a limited role in detecting
esophageal cancer and nodal staging. 相似文献
11.
Apparent diffusion coefficient in cervical cancer of the uterus: comparison with the normal uterine cervix 总被引:22,自引:7,他引:22
A relation between apparent diffusion coefficient (ADC) values and tumor cellular density has been reported. The purpose of this study was to measure the ADC values of cervical cancers in the uterus and compare them with those of normal cervical tissues, and to test whether ADC could differentiate between normal and malignant cervical tissues in the uterus. Twelve consecutive female patients with cervical cancer of the uterus and ten female patients with other pelvic abnormalities were included in this study. ADC was measured at 1.5 T with b-factors of 0, 300 and 600 s/mm2 using single-shot echo-planar diffusion-weighted imaging and a parallel imaging technique. The mean ADC value of cervical cancer lesions was 1.09±0.20×10–3 mm2/s, and that of normal cervix tissue was 1.79±0.24×10–3 mm2/s (P<0.0001). In nine patients treated by chemotherapy and/or radiation therapy, the mean ADC value of the cervical cancer lesion increased significantly after therapy (P<0.001). The present study showed, with a small number of patients, that ADC measurement has a potential ability to differentiate between normal and cancerous tissue in the uterine cervix. Further study is necessary to determine the accuracy of ADC measurement in monitoring the treatment response. 相似文献
12.
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
13.
Bruegel M Holzapfel K Gaa J Woertler K Waldt S Kiefer B Stemmer A Ganter C Rummeny EJ 《European radiology》2008,18(3):477-485
The aim of this study was to determine apparent diffusion coefficients (ADCs) of focal liver lesions on the basis of a respiratory
triggered diffusion-weighted single-shot echo-planar MR imaging sequence (DW-SS-EPI) and to evaluate whether ADC measurements
can be used to characterize lesions. One hundred and two patients with focal liver lesions [11 hepatocellular carcinomas (HCC),
82 metastases, 4 focal nodular hyperplasias (FNH), 56 hemangiomas and 51 cysts; mean size, 16.6 mm; range 5–92 mm] were examined
on a 1.5-T system using respiratory triggered DW-SS-EPI (b-values: 50, 300, 600 s/mm2). Results were correlated with histopathologic data and follow-up imaging. The ADCs of different lesion types were compared,
and lesion discrimination using optimal thresholds for ADCs was evaluated. Mean ADCs (×10−3mm2/s) were 1.24 and 1.04 for normal and cirrhotic liver parenchyma and 1.05, 1.22, 1.40, 1.92 and 3.02 for HCCs, metastases,
FNHs, hemangiomas and cysts, respectively. Mean ADCs differed significantly for all lesion types except for comparison of
metastases with HCCs and FNHs. Overall, 88% of lesions were correctly classified as benign or malignant using a threshold
value of 1.63 × 10−3mm2/s. Measurements of the ADCs of focal liver lesions on the basis of a respiratory triggered DW-SS-EPI sequence may constitute
a useful supplementary method for lesion characterization. 相似文献
14.
Objective
We aimed to detect the frequency of restricted diffusion in intracerebral metastases and to find whether there is correlation between the primary tumor pathology and diffusion-weighted MR imaging (DWI) findings of these metastases.Material and methods
87 patients with intracerebral metastases were examined with routine MR imaging and DWI. 11 hemorrhagic metastatic lesions were excluded. The routine MR imaging included three plans before and after contrast enhancement. The DWI was performed with spin-echo EPI sequence with three b values (0, 500 and 1000), and ADC maps were calculated. 76 patients with metastases were grouped according to primary tumor histology and the ratios of restricted diffusion were calculated according to these groups. ADCmin values were measured within the solid components of the tumors and the ratio of metastases with restricted diffusion to that which do not show restricted diffusion were calculated. Fisher's exact and Mann-Whitney U tests were used for the statistical analysis.Results
Restricted diffusion was observed in a total of 15 metastatic lesions (19, 7%). Primary malignancy was lung carcinoma in 10 of these cases (66, 6%) (5 small cell carcinoma, 5 non-small cell carcinoma), and breast carcinoma in three cases (20%). Colon carcinoma and testicular teratocarcinoma were the other two primary tumors in which restricted diffusion in metastasis was detected. There was no statistical significant difference between the primary pathology groups which showed restricted diffusion (p > 0.05). ADCmin values of solid components of the metastasis with restricted diffusion and other metastasis without restricted diffusion also showed no significant statistical difference (0.72 ± 0.16 × 10−3 mm2/s and 0.78 ± 21 × 10−3 mm2/s respectively) (p = 0.325).Conclusion
Detection of restricted diffusion on DWI in intracerebral metastasis is not rare, particularly if the primary tumor is lung or breast cancer. However we found that there is no correlation between the metastasis showing restricted diffusion and primary pathology. Prospective studies with larger groups and more information are necessary regarding the correlation between the primary tumor histopathology and the ADC values of metastasis with restricted diffusion. 相似文献15.
Reproducibility of brain ADC histograms 总被引:3,自引:0,他引:3
Steens SC Admiraal-Behloul F Schaap JA Hoogenraad FG Wheeler-Kingshott CA le Cessie S Tofts PS van Buchem MA 《European radiology》2004,14(3):425-430
The aim of this study was to assess the effect of differences in acquisition technique on whole-brain apparent diffusion coefficient (ADC) histogram parameters, as well as to assess scan–rescan reproducibility. Diffusion-weighted imaging (DWI) was performed in 7 healthy subjects with b-values 0–800, 0–1000, and 0–1500 s/mm2 and fluid-attenuated inversion recovery (FLAIR) DWI with b-values 0–1000 s/mm2. All sequences were repeated with and without repositioning. The peak location, peak height, and mean ADC of the ADC histograms and mean ADC of a region of interest (ROI) in the white matter were compared using paired-sample t tests. Scan–rescan reproducibility was assessed using paired-sample t tests, and repeatability coefficients were reported. With increasing maximum b-values, ADC histograms shifted to lower values, with an increase in peak height (p<0.01). With FLAIR DWI, the ADC histogram shifted to lower values with a significantly higher, narrower peak (p<0.01), although the ROI mean ADC showed no significant differences. For scan–rescan reproducibility, no significant differences were observed. Different DWI pulse sequences give rise to different ADC histograms. With a given pulse sequence, however, ADC histogram analysis is a robust and reproducible technique. Using FLAIR DWI, the partial-voluming effect of cerebrospinal fluid, and thus its confounding effect on histogram analyses, can be reduced. 相似文献
16.
Andreas Biffar Olaf Dietrich Michael Ingrisch Andrea Baur-Melnyk 《European journal of radiology》2010,76(3):298-303
Objectives
To evaluate the potential and to analyze parameter correlations of combined quantitative diffusion-weighted MRI (DWI) and high-temporal-resolution dynamic contrast-enhanced MRI (DCE-MRI) in vertebral bone marrow (vBM) of patients with osteoporosis and acute vertebral compression fractures, providing additional information for a better understanding of the physiological background of parameter changes.Materials and methods
20 patients with acute osteoporotic fractures were examined with DWI and DCE-MRI at 1.5 T. DCE-MRI was performed with a 2D saturation-recovery turbo-FLASH sequence, acquiring 300 dynamics with a temporal resolution of 1 s. For DWI measurements, a DW HASTE sequence with b-values from 100 to 600 s/mm2 was applied. In each patient, ROIs were drawn manually in the fractures and in normal appearing vertebrae. For DCE-MRI, the concentration-time curves of these ROIs were analyzed using a two-compartment tracer-kinetic model in the lesions, providing separate estimates of perfusion and permeability, and a one-compartment model in normal vBM, providing only a mixed representation of perfusion and permeability in terms of a mixed flow parameter Ktrans and the extracellular volume (ECV). In the case of DWI, attenuation curves were fitted to a monoexponential decay model to determine the apparent diffusion coefficient (ADC).Results
Mean perfusion parameters and ADCs were significantly (p < 0.001) different in the fractures compared to adjacent normal appearing vertebrae (Ktrans: 7.81 mL/100 mL/min vs. 14.61 mL/100 mL/min, ECV: 52.84 mL/100 mL vs. 4.61 mL/100 mL, ADC: 1.71 × 10-3 mm2/s vs. 0.57 × 10-3 mm2/s). ADCs showed a significant correlation with the ECV.Conclusion
The quantitative analysis of DWI and DCE-MRI could distinguish osteoporotic fractures from normal appearing vertebrae. A significant correlation found between ECV and ADCs might be able to explain the cause for the increased diffusivity in osteoporotic fractures. Since the other perfusion parameters do not correlate with the ADC, they provide additional pathophysiological information not accessible with DWI. 相似文献17.
Diffusion-weighted MRI in cystic or necrotic intracranial lesions 总被引:11,自引:2,他引:9
Our purpose was to investigate the signal intensities of cystic or necrotic intracranial lesions on diffusion-weighted MRI
(DWI) and measure their apparent diffusion coefficients (ADC). We examined 39 cystic or necrotic intracranial lesions in 33
consecutive patients: five malignant gliomas, seven metastases, two other necrotic tumours, a haemangioblastoma, three epidermoids,
an arachnoid cyst, seven pyogenic abscesses, 12 cases of cysticercosis and one of radiation necrosis. DWI was performed on
a 1.5 T unit using a single-shot echo-planar spin-echo pulse sequence with b 1000 s/mm2. The signal intensity of the cystic or necrotic portion on DWI was classified by visual assessment as markedly low (as low
as cerebrospinal fluid), slightly lower than, isointense with, and slightly or markedly higher than normal brain parenchyma.
ADC were calculated in 31 lesions using a linear estimation method with measurements from b of 0 and 1000 s/mm2. The cystic or necrotic portions of all neoplasms (other than two metastases) gave slightly or markedly low signal, with
ADC of more than 2.60 × 10−3 mm2/s. Two metastases in two patients showed marked high signal, with ADC of 0.50 × 10−3 mm2/s and 1.23 × 10−3 mm2/s, respectively. Epidermoids showed slight or marked high signal, with ADC of less than 1.03 × 10−3 mm2/s. The arachnoid cyst gave markedly low signal, with ADC of 3.00 × 10−3 mm2/s. All abscesses showed marked high signal, with ADC below 0.95 × 10−3 mm2/s. The cases of cysticercosis showed variable signal intensity; markedly low in five, slightly low in three and markedly
high in four.
Received: 17 November 1999/Accepted: 3 February 2000 相似文献
18.
Sherif Abdelfattah Khedr Mohamed Abdelfattah Hassaan Naglaa Mohamed Abdelrazek Amr yehia Sakr 《The Egyptian Journal of Radiology and Nuclear Medicine》2012
Purpose
To evaluate the diagnostic impact of echo planar DW imaging in distinguishing benign from malignant musculoskeletal soft-tissue masses using ADC mapping as a quantitative assessment tool.Patients and methods
We evaluated 73 tumors (21 bone tumors and 52 soft-tissue tumors). MR examinations were performed with a 1.5-T system. Diffusion-weighted single-shot EPI images were obtained in all patients. Apparent diffusion coefficients (ADCs) were calculated by using b factors of 0 and 1000 s/mm2. ADC value measurements were compared with the histopathological findings.Results
The average ADC of benign tumors was 1.86 ± 0.67 × 10−3 mm2/s, and that of malignant soft-tissue tumors was 0.97 ± 0.35 × 10−3 mm2/s. ADC value of malignant tumors was significantly lower than that of the benign tumor group (p < 0.0001). The highest ADC value was seen in the case of ganglion cyst (2.8 ± 0.23 × 10−3 mm2/s) and cystic neurofibroma (2.5 ± 0.04 × 10−3 mm2/s), and juxta cortical enchondroma (2.65 ± 0.36 × 10−3 mm2/s) while the lowest one was seen in aggressive fibromatosis (0.37 ± 0.05 × 10−3 mm2/s). For malignant soft-tissue masses, the highest ADC value was seen in mesenchymal chondrosarcoma (2.1 ± 0.32) liposarcoma (intermediate grade) (1.4 ± 0.21) while the lowest ADC value was seen in fibrosarcoma (high grade) (0.78 ± 0.14).Conclusion
MR diffusion provides additional information to the routine MRI sequences rendering it an effective non-invasive tool in differentiating between benign and malignant soft-tissue tumors. 相似文献19.
Han KT Choi DS Ryoo JW Cho JM Jeon KN Bae KS You JJ Chung SH Koh EH Park KJ 《Neuroradiology》2007,49(10):813-818
Introduction Pyogenic intraventricular empyema (PIE) is a potentially fatal CNS infection. However, it is sometimes difficult to diagnose
PIE on the basis of clinical and conventional MRI findings. Diffusion-weighted imaging (DWI) has been accepted as a useful
MR sequence for the diagnosis of various intracranial infections. The purpose of this study was to determine the DWI characteristics
of PIE and the role of DWI in the diagnosis of PIE.
Methods Eight patients with PIE underwent MRI including DWI. We assessed the presence and signal characteristics of PIE. In seven
patients, the signal intensities of the PIE and cerebrospinal fluid (CSF) were measured and the contrast-to-noise ratio (CNR)
percentage was calculated. ADC values of the PIE, CSF, and white matter were also determined.
Results PIE was detected in all patients by DWI, in five (63%) by FLAIR imaging, and in two (25%) by T1- and T2-weighted imaging.
The CNR percentages of the PIEs in relation to the CSF were highest for DWI, followed by FLAIR, T1-, and T2-weighted imaging.
There were statistically significant differences between the images of each sequence. In all patients, PIE showed hyperintensities
on DWI and hypointensities to the CSF and hypo- or isointensities to the white matter on ADC maps. The ADC values (mean±SD)
of the PIE, CSF, and white matter were 0.60±0.27, 2.81±0.04, and 0.79±0.08 (×10−3 mm2/s). There was a statistically significant difference between PIE and the CSF.
Conclusion PIE shows a bright intensity on DWI, and DWI is a sensitive MR sequence for the diagnosis of PIE. 相似文献
20.
Svetlana Gavrilovic Slobodan Lavrnic Majda Thurnher Marija Macvanski Danica Grujicic Tatjana Stosic-Opincal 《European Journal of Radiology Extra》2011,79(2):e59-e62