共查询到20条相似文献,搜索用时 31 毫秒
1.
Monique D. Dorrius Hildebrand Dijkstra Matthijs Oudkerk Paul E. Sijens 《European radiology》2014,24(11):2835-2847
Objectives
To evaluate the effect of the choice of b values and prior use of contrast medium on apparent diffusion coefficients (ADCs) of breast lesions derived from diffusion-weighted imaging (DWI), and on the discrimination between benign and malignant lesions.Methods
A literature search of relevant DWI studies was performed. The accuracy of DWI to characterize lesions by using b value ≤600 s/mm2 and b value >600 s/mm2 was presented as pooled sensitivity and specificity, and the ADC was calculated for both groups. Lesions were pooled as pre- or post-contrast DWI.Results
Of 198 articles, 26 met the inclusion criteria. Median ADCs were significantly higher (13.2–35.1 %, p?0.001) for the group of b values ≤600 s/mm2 compared to >600 s/mm2. The sensitivity in both groups was similar (91 % and 89 %, p?=?0.495) as well as the specificity (75 % and 84 %, p?=?0.237). Contrast medium had no significant effects on the ADCs (p?≥?0.08). The differentiation between benign and malignant lesions was optimal (58.4 %) for the combination of b?=?0 and 1,000 s/mm2.Conclusions
The wide variety of b value combinations applied in different studies significantly affects the ADC of breast lesions and confounds quantitative DWI. If only a couple of b values are used, those of b?=?0 and 1,000 s/mm2 are recommended for the best improvement of differentiating between benign and malignant lesions.Key Points
? The choice of b values significantly affects the ADC of breast lesions. ? Sensitivity and specificity are not affected by the choice of b values. ? b values 0 and 1,000 s/mm 2 are recommended for optimal differentiation between benign and malignant lesions. ? Contrast medium prior to DWI does not significantly affect the ADC. 相似文献2.
Rania A. Maarouf Dalia Z. ZidanMaha A. El-Shinnawy 《The Egyptian Journal of Radiology and Nuclear Medicine》2013
Purpose
To investigate the added value of diffusion-weighted imaging (DWI) to magnetic resonance cholangiopancreatography (MRCP) in differentiating benign from malignant extrahepatic biliary strictures.Methods
Magnetic resonance examination including, T2-weighted imaging, MRCP and DWI using different b-values (0,500,800 s/mm2) were performed in 38 patients with suspicious extrahepatic biliary strictures. Apparent diffusion coefficient (ADC) value was calculated. The signal intensity of the lesions on DWI using b = 500 and 800 s/mm2 was examined. Analysis of the DWI and MRCP images for the cause of the extrahepatic biliary stricutre was performed. Patients were further confirmed by histopathological diagnosis and follow up. Sensitivity, specificity, accuracy, positive predictive and negative predictive values were calculated for both the MRCP images and DWI.Results
Of the 38 cases, 23 cases had malignant extrahepatic biliary strictures and 15 had benign strictures. DWI detected 21 out of the 23 malignant biliary strictures and 14 out of 15 benign biliary strictures. Malignant strictures more frequently appeared hyperintense than benign strictures on DWI using b-values of 500 and 800 s/mm2. There was a significant difference in sensitivity (91.3% vs. 73%), specificity (93.3% vs. 64.7%), accuracy (92.1% vs. 73.6%), positive predictive value (95.4% vs. 81%), and negative predictive value (87.5% vs. 64.7%) between DWI and MRCP in differentiating biliary strictures.Conclusion
Combined evaluation using DWI added to MRCP improves the differentiation of malignant from benign extrahepatic biliary strictures. 相似文献3.
Purpose
The role of diffusion-weighted MR imaging (DWI) in the differential diagnosis of pulmonary malignant tumours and solid benign lesions was investigated.Methods
Sixty-two patients with 66 lesions underwent conventional MRI and DWI (diffusion factor of 0 and 500 s/mm2) examinations with 1.5-T MRI. The signal intensity of DWI images was observed and the apparent diffusion coefficient (ADC) values of the lesions were measured. Statistical analyses were performed with the independent samples t test, Pearson’s chi-square test and receiver operating characteristic (ROC) analysis.Results
The signal intensities of pulmonary malignant tumours and solid benign lesions were not significantly different, but the ADC value of benign lesions was statistically higher than that of malignant tumours (p?=?0.001). By ROC analysis, the optimal threshold of ADC was 1.400?×?10–3 mm2/s and the sensitivity and specificity were 83.3% and 74.1%, respectively. There were statistical differences between small cell carcinoma (SCLC) and non-small cell carcinoma (NSCLC) as well; the former was lower than the latter (p?=?0.007).Conclusion
Our data indicate that quantitative analysis of ADC values may help diagnose or distinguish pulmonary lesions, and it also provides a promising method for characterising the pulmonary masses. 相似文献4.
Luísa Nogueira Sofia Brandão Eduarda Matos Rita Gouveia Nunes Joana Loureiro Isabel Ramos Hugo Alexandre Ferreira 《European radiology》2014,24(6):1197-1203
Objectives
To evaluate diffusion-weighted imaging (DWI) and diffusion kurtosis imaging (DKI) in the differentiation and characterisation of breast lesions.Methods
Thirty-six women underwent breast magnetic resonance imaging (MRI) including a DWI sequence with multiple b-values (50–3,000 s/mm2). Mean values for apparent diffusion coefficient (ADC), mean diffusivity (MD) and mean kurtosis (MK) were calculated by lesion type and histological subtype. Differences and correlation between parameters were determined.Results
Forty-four lesions were found. There were significant differences between benign and malignant lesions for all parameters (ADC, p?=?0.017; MD, p?=?0.028; MK, p?=?0.017). ADC and MD were higher for benign (1.96?±?0.41?×?10?3 and 2.17?±?0.42?×?10?3 mm2/s, respectively) than for malignant lesions (1.33?±?0.18?×?10?3 and 1.52?±?0.50?×?10?3 mm2/s). MK was higher for malignant (0.61?±?0.27) than benign lesions (0.37?±?0.18). We found differences between invasive ductal carcinoma (IDC) and fibroadenoma (FA) for all parameters (ADC, MD and MK): p?=?0.016, 0.022 and 0.016, respectively. FA and fibrocystic change (FC) showed differences only in MK (p?=?0.016).Conclusions
Diffusion in breast lesions follows a non-Gaussian distribution. MK enables differentiation and characterisation of breast lesions, providing new insights into microstructural complexity. To confirm these results, further investigation in a broader sample should be performed.Key Points
? The diffusion kurtosis model provides new information regarding breast lesions ? MD and MK are valid parameters to characterise tissue microstructure ? MK enables improved lesion differentiation ? MK is able to differentiate lesions that display similar ADC values 相似文献5.
Claudio Spick Katja Pinker-Domenig Margaretha Rudas Thomas H. Helbich Pascal A. Baltzer 《European radiology》2014,24(6):1204-1210
Objective
To assess if the application of diffusion-weighted imaging (DWI) obviates unnecessary MR-guided biopsies in suspicious breast lesions visible only on contrast-enhanced MRI (CE-MRI).Methods
This institutional review board (IRB)-approved, retrospective, single-centre study included 101 patients (mean age, 49.5; SD 13.9 years) who underwent additional DWI at 1.5 T prior to MRI-guided biopsy of 104 lesions classified as suspicious for malignancy and visible on CE-MRI only. An experienced radiologist, blinded to histopathologic and follow-up results, measured apparent diffusion coefficient (ADC) values obtained from DWI. Diagnostic accuracy was investigated using receiver operating characteristics (ROC) analysis.Results
Histopathology revealed 20 malignant and 84 benign lesions. Lesions were masses in 61 (15 malignant, 24.6 %) and non-masses in 43 cases (five malignant, 11.6 %). Mean ADC values were 1.53?±?0.38?×?10?3 mm2/s in benign lesions and 1.06?±?0.27?×?10?3 mm2/s in malignant lesions. ROC analysis revealed exclusively benign lesions if ADC values were greater than 1.58?×?10?3 mm2/s. As a consequence, 29 false-positive biopsies (34.5 %) could have been avoided without any false-negative findings. Both in mass and in non-mass lesions, rule-in and rule-out criteria were identified using flexible ADC thresholds based on ROC analysis.Conclusion
Additional application of DWI in breast lesions visible only on MRI can avoid false-positive, MR-guided biopsies. Thus, DWI should be an integral part of breast MRI protocols.Key Points
? DWI measurements are a fast and helpful technique for improved breast lesion diagnosis ? DWI application in breast lesions visible only on MRI obviates false-positive, MR-guided biopsies ? Flexible ADC thresholds provide rule-in and rule-out criteria for breast lesion malignancy 相似文献6.
Hyun Jeong Park Seong Hyun Kim Kyung Mi Jang Seo-youn Choi Soon Jin Lee Dongil Choi 《European radiology》2014,24(4):947-958
Objectives
To assess the added value of diffusion-weighted imaging (DWI) to conventional magnetic resonance imaging (MRI) for differentiating benign from malignant bile duct strictures.Methods
Twenty-seven patients with a benign stricture and 42 patients with a malignant stricture who had undergone gadoxetic acid-enhanced MRI with DWI were enrolled. Qualitative (signal intensity, dynamic enhancement pattern) and quantitative (wall thickness and length) analyses were performed. Two observers independently reviewed a set of conventional MRI and a combined set of conventional MRI and DWI, and receiver operating characteristic (ROC) curve analysis was assessed.Results
Benign strictures showed isointensity (18.5–70.4 %) and a similar enhancement pattern (22.2 %) to that of normal bile duct more frequently than malignant strictures (0–40.5 % and 0 %) on conventional MRI (P?<?0.05). Malignant strictures (90.5–92.9 %) showed hypervascularity on arterial and portal venous phase images more frequently than benign strictures (37.0–70.4 %) (P?<?0.01) On DWI, all malignant strictures showed hyperintensity compared with benign cases (70.4 %) (P?<?0.001). Malignant strictures were significantly thicker and longer than benign strictures (P?<?0.001). The diagnostic performance of both observers improved significantly after additional review of DWI.Conclusions
Adding DWI to conventional MRI is more helpful for differentiating benign from malignant bile duct strictures than conventional MRI alone.Key points
? Accurate diagnosis and exclusion of benign strictures of bile duct are important. ? Diffusion-weighted MRI helps to distinguish benign from malignant bile duct strictures. ? DWI plus conventional MRI provides superior diagnostic accuracy to conventional MRI alone. 相似文献7.
E. A. Lassel R. Rao C. Schwenke S. O. Schoenberg H. J. Michaely 《European radiology》2014,24(1):241-249
Objectives
Contrast-enhanced MRI can only distinguish to a limited extent between malignant and benign focal renal lesions. The aim of this meta-analysis is to review renal diffusion-weighted imaging (DWI) to compare apparent diffusion coefficient (ADC) values for different renal lesions that can be applied in clinical practice.Methods
A PubMed search was performed to identify relevant articles published 2004–2011 on renal DWI of focal renal lesions. ADC values were extracted by lesion type to determine whether benign or malignant. The data table was finalised in a consensus read. ADC values were evaluated statistically using meta-regression based on a linear mixed model. Two-sided P value <5 % indicated statistical significance.Results
The meta-analysis is based on 17 studies with 764 patients. Renal cell carcinomas have significant lower ADC values than benign tissue (1.61?±?0.08?×?10-3 mm2/s vs 2.10?±?0.09?×?10-3 mm2/s; P?<?0.0001). Uroepithelial malignancies can be differentiated by lowest ADC values (1.30?±?0.11?×?10-3 mm2/s). There is a significant difference between ADC values of renal cell carcinomas and oncocytomas (1.61?±?0.08?×?10-3 mm2/s vs 2.00?±?0.08?×?10-3 mm2/s; P?<?0.0001).Conclusions
Evaluation of ADC values can help to determine between benign and malignant lesions in general but also seems able to differentiate oncocytomas from malignant tumours, hence potentially reducing the number of unnecessarily performed nephrectomies.Key Points
? This meta-analysis assesses the role of diffusion-weighted MRI in renal lesions. ? ADC values obtained by DW MRI have been compared for different renal lesions. ? ADC values can help distinguish between benign and malignant tumours. ? Differentiating oncocytomas from malignant tumours can potentially reduce inappropriate nephrectomies. 相似文献8.
Marlijne E. Ikink Marianne J. Voogt Maurice A. A. J. van den Bosch Robbert J. Nijenhuis Bilgin Keserci Young-sun Kim Koen L. Vincken Lambertus W. Bartels 《European radiology》2014,24(9):2118-2127
Objectives
To assess the value of diffusion-weighted magnetic resonance imaging (DWI) and apparent diffusion coefficient (ADC) mapping using different b-value combinations for treatment evaluation after magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) of uterine fibroids.Methods
Fifty-six patients with 67 uterine fibroids were treated with volumetric MR-HIFU. Pre-treatment and post-treatment images were obtained using contrast-enhanced T1-weighted MRI (CE-T1WI) and DWI using b?=?0, 200, 400, 600, 800 s/mm2. ADC maps were generated using subsets of b-values to investigate the effects of tissue ablation on water diffusion and perfusion in fibroids treated with MR-HIFU. Four combinations of b-values were used: (1) all b-values; (2) b?=?0, 200 s/mm2; (3) b?=?400, 600, 800 s/mm2; and (4) b?=?0, 800 s/mm2.Results
Using the lowest b-values (0 and 200 s/mm2), the mean ADC value in the ablated tissue reduced significantly (p?0.001) compared with baseline. Calculating the ADC value with the highest b-values (400, 600, 800 s/mm2), the ADC increased significantly (p?0.001) post-treatment. ADC maps calculated with the lowest b-values resulted in the best visual agreement of non-perfused fibroid tissue detected on CE images. Other b-value combinations and normal myometrium showed no difference in ADC after MR-HIFU treatment.Conclusions
A decrease in contrast agent uptake within the ablated region on CE-T1WI was correlated to a significantly decreased ADC when b?=?0 and 200 s/mm2 were used.Key Points
? DWI could be useful for treatment evaluation after MR-HIFU of uterine fibroids ? The ADC in fibroid tissue is influenced by the choice of b- values ? Low b-values seem the best choice to emphasise perfusion effects after MR-HIFU 相似文献9.
L. Bernardin N. H. M. Douglas D. J. Collins S. L. Giles E. A. M. O’Flynn M. Orton N. M. deSouza 《European radiology》2014,24(2):502-511
Purpose
To establish repeatability of apparent diffusion coefficients (ADCs) acquired from free-breathing diffusion-weighted magnetic resonance imaging (DW-MRI) in malignant lung lesions and investigate effects of lesion size, location and respiratory motion.Methods
Thirty-six malignant lung lesions (eight patients) were examined twice (1- to 5-h interval) using T1-weighted, T2-weighted and axial single-shot echo-planar DW-MRI (b?=?100, 500, 800 s/mm2) during free-breathing. Regions of interest around target lesions on computed b?=?800 s/mm2 images by two independent observers yielded ADC values from maps (pixel-by-pixel fitting using all b values and a mono-exponential decay model). Intra- and inter-observer repeatability was assessed per lesion, per patient and by lesion size (> or <2 cm) or location.Results
ADCs were similar between observers (mean ± SD, 1.15?±?0.28?×?10-3 mm2/s, observer 1; 1.15?±?0.29?×?10-3 mm2/s, observer 2). Intra-observer coefficients of variation of the mean [median] ADC per lesion and per patient were 11 % [11.4 %], 5.7 % [5.7 %] for observer 1 and 9.2 % [9.5 %], 3.9 % [4.7 %] for observer 2 respectively; inter-observer values were 8.9 % [9.3 %] (per lesion) and 3.0 % [3.7 %] (per patient). Inter-observer coefficient of variation (CoV) was greater for lesions <2 cm (n?=?20) compared with >2 cm (n?=?16) (10.8 % vs 6.5 % ADCmean, 11.3 % vs 6.7 % ADCmedian) and for mid (n?=?14) vs apical (n?=?9) or lower zone (n?=?13) lesions (13.9 %, 2.7 %, 3.8 % respectively ADCmean; 14.2 %, 2.8 %, 4.7 % respectively ADCmedian).Conclusion
Free-breathing DW-MRI of whole lung achieves good intra- and inter-observer repeatability of ADC measurements in malignant lung tumours.Key Points
? Diffusion-weighted MRI of the lung can be satisfactorily acquired during free-breathing ? DW-MRI demonstrates high contrast between primary and metastatic lesions and normal lung ? Apparent diffusion coefficient (ADC) measurements in lung tumours are repeatable and reliable ? ADC offers potential in assessing response in lung metastases in clinical trials 相似文献10.
P. Belli M. Costantini E. Bufi A. Magistrelli G. La Torre L. Bonomo 《La Radiologia medica》2010,115(1):51-69
Purpose
The purpose of this study was to investigate the ability of diffusion-weighted imaging (DWI) and the apparent diffusion coefficient (ADC) in the detection and characterisation of breast lesions.Materials and methods
From September 2005 to September 2007, 86 patients with breast lesions who underwent magnetic resonance imaging (MRI) in our department were included in our study. MRI was performed with a 1.5-T unit using a standard protocol including DWI sequence. For each breast lesion, the ADC value was calculated and compared with that of normal breast tissue and to the definitive pathological diagnosis. Mann-Whitney U and Kruskal-Wallis tests were used for statistical analysis.Results
A total of 126 breast lesions were detected. Pathology results revealed 100 malignant and 26 benign lesions. Mean diameter of lesions was 26.02 mm (range 4–90 mm), including 52 lesions ≤15 mm in size. Mean ADC value of normal glandular tissue was 1.55×10?3 mm2/s. Mean ADC value of malignant lesions was 0.97×10?3 mm2/s. Mean ADC value for benign lesions was 1.66×10?3 mm2/s. Benign lesions showed ADC values significantly higher than malignant lesions (p<0.0001).Conclusions
DWI provides reliable information to support MRI diagnosis of breast masses. ADC value appears a promising adjunctive parameter in distinguishing malignant from benign breast lesions. 相似文献11.
Andrew B. Rosenkrantz Hersh Chandarana Nicole Hindman Fang-Ming Deng James S. Babb Samir S. Taneja Christian Geppert 《European radiology》2013,23(11):3170-3177
Objectives
To investigate the impact of prostate computed diffusion-weighted imaging (DWI) on image quality and tumour detection.Methods
Forty-nine patients underwent 3-T magnetic resonance imaging using a pelvic phased-array coil before prostatectomy, including DWI with b values of 50 and 1,000 s/mm2. Computed DW images with b value 1,500 s/mm2 were generated from the lower b-value images. Directly acquired b-1,500 DW images were obtained in 39 patients. Two radiologists independently assessed DWI for image quality measures and location of the dominant lesion. A third radiologist measured tumour-to-peripheral-zone (PZ) contrast. Pathological findings from prostatectomy served as the reference standard.Results
Direct and computed b-1,500 DWI showed better suppression of benign prostate tissue than direct b-1,000 DWI for both readers (P?≤?0.024). However, computed b-1,500 DWI showed less distortion and ghosting than direct b-1,000 and direct b-1,500 DWI for both readers (P?≤?0.067). Direct and computed b-1,500 images showed better sensitivity and positive predictive value (PPV) for tumour detection than direct b-1,000 images for both readers (P?≤?0.062), with no difference in sensitivity or PPV between direct and computed b-1,500 images (P?≥?0.180). Tumour-to-PZ contrast was greater on computed b-1,500 than on either direct DWI set (P?<?0.001).Conclusion
Computed DWI of the prostate using b value ≥1,000 s/mm2 improves image quality and tumour detection compared with acquired standard b-value images.Key Points
? Diffusion weighted MRI is increasingly used for diagnosing and assessing prostate carcinoma. ? Prostate computed DWI can extrapolate high b-value images from lower b values. ? Computed DWI provides greater suppression of benign tissue than lower b-value images. ? Computed DWI provides less distortion and artefacts than images using same b value. ? Computed DWI provides better diagnostic performance than lower b-value images. 相似文献12.
Johan Coolen Johan Vansteenkiste Frederik De Keyzer Herbert Decaluwé Walter De Wever Christophe Deroose Christophe Dooms Eric Verbeken Paul De Leyn Vincent Vandecaveye Dirk Van Raemdonck Kristiaan Nackaerts Steven Dymarkowski Johny Verschakelen 《European radiology》2014,24(2):531-541
Objective
To evaluate the diagnostic accuracy of dynamic contrast-enhanced (DCE) magnetic resonance (MR) and diffusion-weighted imaging (DWI) sequences for defining benignity or malignancy of solitary pulmonary lesions (SPL).Methods
First, 54 consecutive patients with SPL, clinically staged (CT and PET or integrated PET-CT) as N0M0, were included in this prospective study. An additional 3-Tesla MR examination including DCE and DWI was performed 1 day before the surgical procedure. Histopathology of the surgical specimen served as the standard of reference. Subsequently, this functional method of SPL characterisation was validated with a second cohort of 54 patients.Results
In the feasibility group, 11 benign and 43 malignant SPL were included. Using the combination of conventional MR sequences with visual interpretation of DCE-MR curves resulted in a sensitivity, specificity and accuracy of 100 %, 55 % and 91 %, respectively. These results can be improved by DWI (with a cut-off value of 1.52?×?10?3 mm2/s for ADChigh) leading to a sensitivity, specificity and accuracy of 98 %, 82 % and 94 %, respectively. In the validation group these results were confirmed.Conclusion
Visual DCE-MR-based curve interpretation can be used for initial differentiation of benign from malignant SPL, while additional quantitative DWI-based interpretation can further improve the specificity.Key Points
? Magnetic resonance imaging is increasingly being used to help differentiate lung lesions. ? Solitary pulmonary lesions (SPL) are accurately characterised by combining DCE-MRI and DWI. ? Visual DCE-MRI assessment facilitates the diagnostic throughput in patients with SPL. ? DWI provides additional information in inconclusive DCE-MRI (type B pattern). 相似文献13.
Luc A. Heijnen Doenja M. J. Lambregts Dipanjali Mondal Milou H. Martens Robert G. Riedl Geerard L. Beets Regina G. H. Beets-Tan 《European radiology》2013,23(12):3354-3360
Objectives
To evaluate the performance of diffusion-weighted MRI (DWI) for the detection of lymph nodes and for differentiating between benign and metastatic nodes during primary rectal cancer staging.Methods
Twenty-one patients underwent 1.5-T MRI followed by surgery (± preoperative 5?×?5 Gy). Imaging consisted of T2-weighted MRI, DWI (b0, 500, 1000), and 3DT1-weighted MRI with 1-mm isotropic voxels. The latter was used for accurate detection and per lesion histological validation of nodes. Two independent readers analysed the signal intensity on DWI and measured the mean apparent diffusion coefficient (ADC) for each node (ADCnode) and the ADC of each node relative to the mean tumour ADC (ADCrel).Results
DWI detected 6 % more nodes than T2W-MRI. The signal on DWI was not accurate for the differentiation of metastatic nodes (AUC 0.45–0.50). Interobserver reproducibility for the nodal ADC measurements was excellent (ICC 0.93). Mean ADCnode was higher for benign than for malignant nodes (1.15?±?0.24 vs. 1.04?±?0.22 *10-3 mm2/s), though not statistically significant (P?=?0.10). Area under the ROC curve/sensitivity/specificity for the assessment of metastatic nodes were 0.64/67 %/60 % for ADCnode and 0.67/75 %/61 % for ADCrel.Conclusions
DWI can facilitate lymph node detection, but alone it is not reliable for differentiating between benign and malignant lymph nodes.Key Points
? Diffusion-weighted (DW) magnetic resonance imaging (MRI) offers new information in rectal cancer. ? DW MRI demonstrates more lymph nodes than standard T2-weighted MRI. ? Visual DWI assessment does not discriminate between benign and metastatic nodes. ? Apparent diffusion coefficients do not discriminate between benign and metastatic nodes. 相似文献14.
Stavroula Kyriazi Matthew Blackledge David J. Collins Nandita M. deSouza 《European radiology》2010,20(10):2422-2431
Objective
To compare geometric distortion, signal-to-noise ratio (SNR), apparent diffusion coefficient (ADC), efficacy of fat suppression and presence of artefact between monopolar (Stejskal and Tanner) and bipolar (twice-refocused, eddy-current-compensating) diffusion-weighted imaging (DWI) sequences in the abdomen and pelvis.Materials and methods
A semiquantitative distortion index (DI) was derived from the subtraction images with b?=?0 and 1,000 s/mm2 in a phantom and compared between the two sequences. Seven subjects were imaged with both sequences using four b values (0, 600, 900 and 1,050 s/mm2) and SNR, ADC for different organs and fat-to-muscle signal ratio (FMR) were compared. Image quality was evaluated by two radiologists on a 5-point scale.Results
DI was improved in the bipolar sequence, indicating less geometric distortion. SNR was significantly lower for all tissues and b values in the bipolar images compared with the monopolar (p?<?0.05), whereas FMR was not statistically different. ADC in liver, kidney and sacrum was higher in the bipolar scheme compared to the monopolar (p?<?0.03), whereas in muscle it was lower (p?=?0.018). Image quality scores were higher for the bipolar sequence (p?≤?0.025).Conclusion
Artefact reduction makes the bipolar DWI sequence preferable in abdominopelvic applications, although the trade-off in SNR may compromise ADC measurements in muscle. 相似文献15.
P. Mürtz M. Tsesarskiy A. Kowal F. Träber J. Gieseke W. A. Willinek C. C. Leutner A. Schmiedel H. H. Schild 《European radiology》2014,24(10):2540-2551
Objective
The aim of this study was to evaluate the influence of different fat-suppression techniques on quantitative measurements and their reproducibility when applied to diffusion-weighted imaging (DWI) of breast lesions.Methods
Twenty-five patients with different types of breast lesions were examined on a clinical 1.5-T magnetic resonance imaging (MRI) system. Two diffusion-weighted sequences with different fat-suppression methods were applied: one with spectral presaturation by inversion recovery (SPIR), and one with short-TI inversion recovery (STIR). The acquisition of both sequence variants was repeated with modified shim volume. Lesion-to-background contrast (LBC), apparent diffusion coefficients (ADC) ADC(0,1000) and ADC(50,1000), and their coefficients of variation (CV) were determined.Results
In four patients, the image quality of DWI with SPIR was insufficient. In the other 21 patients, 46 regions of interest (ROI), including 11 malignant and 35 benign lesions, were analysed. The LBC, ADC(0,1000) and ADC(50,1000) values, which did not differ between initial and repeated measurements, were significantly higher for STIR than for SPIR. The mean CV improved from 10.8 % to 4.0 % (P?=?0.0047) for LBC, from 6.3 % to 2.9 % (P?=?0.0041) for ADC(0,1000), and from 6.3 % to 2.6 % (P?=?0.0049) for ADC(50,1000).Conclusion
For STIR compared to SPIR fat suppression, improved lesion conspicuity, higher ADC values, and better measurement reproducibility were found in breast DWI.Key Points
? Quality of fat suppression influences quantitative DWI breast lesion measurements. ? In breast DWI, STIR fat suppression worked more reliably than SPIR. ? Lesion-to-background contrast and its reproducibility were significantly higher with STIR fat suppression. ? Lesional ADCs and their reproducibility were significantly higher with STIR fat suppression. 相似文献16.
Marcelo A. Queiroz Martin Hüllner Felix Kuhn Gerhardt Huber Christian Meerwein Spyros Kollias Gustav von Schulthess Patrick Veit-Haibach 《European journal of nuclear medicine and molecular imaging》2014,41(12):2212-2221
Objective
The purpose of this study was to analyze whether diffusion-weighted imaging (DWI) adds significant information to positron emission tomography/magnetic resonance imaging (PET/MRI) on lesion detection and characterization in head and neck cancers.Methods
Seventy patients with different head and neck cancers were enrolled in this prospective study. All patients underwent sequential contrast-enhanced (ce) PET/computed tomography (CT) and cePET/MRI using a tri-modality PET/CT-MR setup either for staging or re-staging. First, the DWI alone was evaluated, followed by the PET/MRI with conventional sequences, and in a third step, the PET/MRI with DWI was evaluated. McNemar’s test was used to evaluate differences in the accuracy of PET/MRI with and without DWI compared to the standard of reference.Results
One hundred eighty-eight (188) lesions were found, and of those, 118 (62.8 %) were malignant and 70 (37.2 %) were benign. PET/MRI without DWI had a higher accuracy in detecting malignant lesions than DWI alone (86.8 % vs. 60.6 %, p?0.001). PET/MRI combined with DWI detected 120 concurrent lesions (89 malignant and 31 benign), PET/MRI alone identified 48 additional lesions (20 malignant and 28 benign), and DWI alone detected 20 different lesions (nine malignant and 11 benign). However, lesions detected on DWI did not change overall staging. SUV maximum and mean were significantly higher in malignant lesions than in benign lesions. DWI parameters between malignant and benign lesions were not statistically different.Conclusion
The use of DWI as part of PET/MRI to evaluate head and neck cancers does not provide remarkable information. Thus, the use of DWI might not be needed in clinical PET/MRI protocols for the staging or restaging of head and neck cancers. 相似文献17.
Savannah C. Partridge PhD Wendy B. DeMartini MD Brenda F. Kurland PhD Peter R. Eby MD Steven W. White BS Constance D. Lehman MD PhD 《Journal of magnetic resonance imaging : JMRI》2010,31(3):562-570
Purpose:
To investigate the diagnostic performance of diffusion‐weighted imaging (DWI) for mammographically and clinically occult breast lesions.Materials and Methods:
The study included 91 women with 118 breast lesions (91 benign, 12 ductal carcinoma in situ [DCIS], 15 invasive carcinoma) initially detected on dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) and assigned BI‐RADS category 3, 4, or 5. DWI was acquired with b = 0 and 600 s/mm2. Lesion visibility was assessed on DWI. Apparent diffusion coefficient (ADC) values were compared between malignancies, benign lesions, and normal (no abnormal enhancement on DCE‐MRI) breast tissue, and the diagnostic performance of DWI was assessed based on ADC thresholding.Results:
Twenty‐four of 27 (89%) malignant and 74/91 (81%) benign lesions were hyperintense on the b = 600 s/mm2 diffusion‐weighted images. Both DCIS (1.33 ± 0.19 × 10?3 mm2/s) and invasive carcinomas (1.30 ± 0.27 × 10?3mm2/s) were lower in ADC than benign lesions (1.71 ± 0.43 × 10?3mm2/s; P < 0.001), and each lesion type was lower in ADC than normal tissue (1.90 ± 0.38 × 10?3mm2/s, P ≤ 0.001). Receiver operating curve (ROC) analysis showed an area under the curve (AUC) of 0.77, and sensitivity = 96%, specificity = 55%, positive predictive value (PPV) = 39%, and negative predictive value (NPV) = 98% for an ADC threshold of 1.60 × 10?3mm2/s.Conclusion:
Many mammographically and clinically occult breast carcinomas were visibly hyperintense on diffusion‐weighted images, and ADC enabled differentiation from benign lesions. Further studies evaluating DWI while blinded to DCE‐MRI are necessary to assess the potential of DWI as a noncontrast breast screening technique. J. Magn. Reson. Imaging 2010;1:562–570. © 2010 Wiley‐Liss, Inc.18.
Ning Lv Ni He Yaopan Wu Chuanmiao Xie Yue Wang Yanan Kong Weidong Wei Peihong Wu 《European radiology》2014,24(11):2848-2856
Objectives
Ultrasound-guided diffuse optical tomography (US-DOT) can potentially detect breast carcinomas by measuring total tumour haemoglobin concentrations (TTHC). The purpose of this study was to evaluate whether vascular haemoglobin concentrations (VHC) affect the ability of US-DOT to distinguish breast carcinomas from benign.Materials and methods
In 85 women (97 palpable lesions) referred for core breast biopsy, we measured VHC with a complete blood count and calculated TTHCs for each lesion with US-DOT. Anaemia was defined as a VHC less than 120.0 g/L.Results
Mean TTHCs were significantly higher in malignant lesions (n?=?53) than in benign lesions (n?=?44), regardless of whether the lesions were from women with anaemia (TTHC, 248.5 vs. 123.3 μmol/L; P?=?0.001) or from those without (TTHC, 229.7 vs. 173.9 μmol/L; P?=?0.016). A cut-off TTHC of 155.1 μmol/L provided 81.3 % sensitivity, 81.8 % specificity and 81.5 % accuracy for detecting malignant tumours in women with anaemia and 78.4 % sensitivity, 54.5 % specificity and 67.1 % accuracy for women without. There was no significant difference in sensitivity (P?=?0.813), specificity (P?=?0.108) and accuracy (P?=?0.162) between the anaemic group and the non-anaemic group.Conclusions
Vascular haemoglobin concentrations did not affect the ability of US-DOT to differentiate breast carcinomas from benign lesions.Key Points
? US-DOT can differentiate benign from malignant breast lesions by measuring TTHC. ? No difference in TTHC between the anaemia and non-anaemia group. ? Vascular haemoglobin concentrations do not affect the diagnostic ability of US-DOT. 相似文献19.
Objectives
To evaluate the value of adding T2- and diffusion-weighted imaging (DWI) to the BI-RADS® classification in MRI-detected lesions.Methods
This retrospective study included 112 consecutive patients who underwent 3.0T structural breast MRI with T2- and DWI on the basis of EUSOMA recommendations. Morphological and kinetic features, T2 signal intensity (T2 SI) and apparent diffusion coefficient (ADC) findings were assessed.Results
Thirty-three (29.5 %) patients (mean age 57.0?±?12.7 years) had 36 primarily MRI-detected incidental lesions of which 16 (44.4 %) proved to be malignant. No single morphological or kinetic feature was associated with malignancy. Both low T2 SI (P?=?0.009) and low ADC values (≤0.87?×?10?3 mm2s?1, P?<?0.001) yielded high specificity (80.0 %/80.0 %). The BI-RADS classification supplemented with information from DWI and T2-WI improved the diagnostic performance of the BI-RADS classification as sensitivity remained 100 % and specificity improved from 30 % to 65.0 %. The numbers of false positive lesions declined from 39 % (N?=?14) to 19 % (N?=?7).Conclusion
MRI-detected incidental lesions may be challenging to characterize as they have few specific malignancy indicating features. The specificity of MRI can be improved by incorporating T2 SI and ADC values into the BI-RADS assessment.Key Points
? MRI-detected incidental lesions have few specific malignancy indicating features. ? ≥ 1 suspicious morphologic or kinetic feature may warrant biopsy. ? T2 signal intensity and DWI assessment are feasible in primarily MRI-detected lesions. ? T2 SI and DWI assessment improve the BI-RADS specificity in MRI-detected lesions.20.
Tibor Vag Matthias M. Heck Ambros J. Beer Michael Souvatzoglou Gregor Weirich Konstantin Holzapfel Bernd Joachim Krause Markus Schwaiger Matthias Eiber Ernst J. Rummeny 《European radiology》2014,24(8):1821-1826