Combination Of Diffusion-weighted Imaging Research Articles

Differentiating Between Primary Central Nervous System Lymphomas and Glioblastomas: Combined Use of Perfusion-Weighted and Diffusion-Weighted Magnetic Resonance Imaging.

The purpose of this study was to determine whether combined diffusion-weighted imaging and dynamic susceptibility contrast-enhanced perfusion-weighted imaging magnetic resonance imaging can be used to differentiate between common malignant brain tumors, including lymphomas and high-grade gliomas. We evaluated 87 patients with histologically confirmed brain tumors, including 33 primary central nervous system lymphomas (PCNSLs) and 54 glioblastomas (GBMs). All patients underwent conventional magnetic resonance imaging, diffusion-weighted imaging, and perfusion-weighted imaging before surgical removal of the lesion or stereotactic biopsy. The maximum relative cerebral blood volume (rCBV) ratios of GBMs were significantly higher than those of PCNSLs (P < 0.0001). The maximum rCBVs helped to distinguish PCNSLs from GBMs with 97.0% sensitivity, 90.7% specificity, and 0.98 area under the curve. The minimum apparent diffusion coefficients (ADCs) of PCNSLs were significantly lower than those of GBMs (P < 0.0001). At an rCBV cutoff value of 4.0 and a minimum ADC of 1.0× 10-3 mm2/second, it was possible to differentiate between PCNSLs and GBMs. The combination of rCBV and ADC can facilitate the differentiation between PCNSLs and GBMs.

The Value of Diffusion-Weighted Imaging in Combination With Conventional Magnetic Resonance Imaging for Improving Tumor Detection for Early Cervical Carcinoma Treated With Fertility-Sparing Surgery.

This study aimed to investigate the value of diffusion-weighted imaging (DWI) in combination with conventional magnetic resonance imaging (MRI) for improving tumor detection in young patients treated with fertility-sparing surgery because of early cervical carcinoma. Fifty-four patients with stage Ia or Ib1 cervical carcinoma were enrolled into this study. Magnetic resonance examinations were performed for these patients using conventional MRI (including T1-weighted imaging, T2-weighted imaging, and dynamic contrast-enhanced MRI) and DWI. The apparent diffusion coefficient (ADC) values of cervical carcinoma were analyzed quantitatively and compared with that of adjacent epithelium. Sensitivity, positive predictive value, and accuracy of 2 sets of MRI sequences were calculated on the basis of histologic results, and the diagnostic ability of conventional MRI/DWI combinations was compared with that of conventional MRI. The mean ADC value from cervical carcinoma (mean, 786 × 10 mm/s ± 100) was significantly lower than that from adjacent epithelium (mean, 1352 × 10 mm/s ± 147) (P = 0.01). When the threshold ADC value set as 1010 × 10 mm/s, the sensitivity and specificity for differentiating cervical carcinoma from nontumor epithelium were 78.2% and 67.2%, respectively. The sensitivity and accuracy of conventional MRI for tumor detection were 76.0% and 70.4%, whereas the sensitivity and accuracy of conventional MRI/DWI combinations were 91.7% and 90.7%, respectively. Conventional MRI/DWI combinations revealed a positive predictive value of 97.8% and only 4 false-negative findings. The addition of DWI to conventional MRI considerably improves the sensitivity and accuracy of tumor detection in young patients treated with fertility-sparing surgery, which supports the inclusion quantitative analysis of ADC value in routine MRI protocol before fertility-sparing surgery.

Study protocol: multi-parametric magnetic resonance imaging for therapeutic response prediction in rectal cancer

BackgroundResponse to neoadjuvant chemoradiotherapy (CRT) of rectal cancer is variable. Accurate imaging for prediction and early assessment of response would enable appropriate stratification of management to reduce treatment morbidity and improve therapeutic outcomes. Use of either diffusion weighted imaging (DWI) or dynamic contrast enhanced (DCE) imaging alone currently lacks sufficient sensitivity and specificity for clinical use to guide individualized treatment in rectal cancer. Multi-parametric MRI and analysis combining DWI and DCE may have potential to improve the accuracy of therapeutic response prediction and assessment.MethodsThis protocol describes a prospective non-interventional single-arm clinical study. Patients with locally advanced rectal cancer undergoing preoperative CRT will prospectively undergo multi-parametric MRI pre-CRT, week 3 CRT, and post-CRT. The protocol consists of DWI using a read-out segmented sequence (RESOLVE), and DCE with pre-contrast T1-weighted (VIBE) scans for T1 calculation, followed by 60 phases at high temporal resolution (TWIST) after gadoversetamide injection. A 3-dimensional voxel-by-voxel technique will be used to produce colour-coded ADC and Ktrans histograms, and data evaluated in combination using scatter plots. MRI parameters will be correlated with surgical histopathology. Histopathology analysis will be standardized, with chemoradiotherapy response defined according to AJCC 7th Edition Tumour Regression Grade (TRG) criteria. Good response will be defined as TRG 0–1, and poor response will be defined as TRG 2–3.DiscussionThe combination of DWI and DCE can provide information on physiological tumour factors such as cellularity and perfusion that may affect radiotherapy response. If validated, multi-parametric MRI combining DWI and DCE can be used to stratify management in rectal cancer patients. Accurate imaging prediction of patients with a complete response to CRT would enable a ‘watch and wait’ approach, avoiding surgical morbidity in these patients. Consistent and reliable quantitation from standardised protocols is essential in order to establish optimal thresholds of ADC and Ktrans and permit the role of multi-parametric MRI for early treatment prediction to be properly evaluated.Trial registrationAustralian New Zealand Clinical Trials Registry (ANZCTR) number ACTRN12616001690448 (retrospectively registered 8/12/2016).

Characterization of small (≤3 cm) hepatic lesions with atypical enhancement feature and hypointensity in hepatobiliary phase of gadoxetic acid-enhanced MRI in cirrhosis: A STARD-compliant article.

It is difficult to characterize the nodular lesions in cirrhotic liver if typical enhancement pattern is not present on dynamic contrast-enhanced imagings. Although the signal intensity of the hepatobiliary phase in gadoxetic acid-enhanced magnetic resonance imaging (MRI) is helpful for characterization of the lesions, some dysplastic nodules may also exhibit low signal intensity in the hepatobiliary phase. We aimed to assess the usefulness of gadoxetic acid (Gd-EOB-DTPA)-enhanced MRI including diffusion-weighted imaging (DWI) for differentiation between atypical small hepatocellular carcinomas (HCCs) and dysplastic nodules showing low signal intensity (SI) in the hepatobiliary phase, and to evaluate the MRI findings in determining the histological grade of atypical HCCs in patients with cirrhosis.A total of 43 cirrhotic patients with a small (≤3 cm) liver nodule (n = 25, HCC; n = 18, dysplastic nodule) who underwent Gd-EOB-DTPA-enhanced MRI and pathologic confirmation were retrospectively reviewed. Atypical HCC was defined as not showing arterial hyperenhancement and delayed washout on dynamic MRI.High SI on both T2WI and DWI (sensitivity 80.0%, specificity 100%, positive predictive value 100%, negative predictive value 78.3%) was the most specific feature to differentiate atypical HCCs from dysplastic nodules. High SI on both T2WI and DWI (100% vs 61.5%, P = .039) or low SI on pre-enhanced T1WI (83.3% vs 30.8%, P = .021) was more frequent observed in Edmonson grade II–III HCCs compared with those in grade I HCCs.The combination of DWI and T2WI is most useful for the differentiation of atypical small HCCs from dysplastic nodules showing low SI in the hepatobiliary phase. Combination of DWI and T2WI or pre-enhanced T1WI seems to be useful for predicting the histological grade of atypical HCCs.

Diagnostic value of combined diffusion-weighted imaging with dynamic contrast enhancement MRI in differentiating malignant from benign bone lesions

To determine the diagnostic value of combined diffusion-weighted imaging (DWI) with dynamic contrast enhancement magnetic resonance imaging (DCE-MRI) in differentiating malignant from benign bone lesions. DWI and DCE-MRI were performed in 36 patients (14 were benign and 22 were malignant). The mean apparent diffusion coefficient (ADC) values and signal enhanced extent (SEE), slope value, and time-signal intensity curve (TIC) type were recorded by two observers. Between-group comparison was made using the independent sample t-test and receiver-operating characteristic (ROC) analysis. There was a significant difference between the mean ADC value of the benign ([1.75±0.50]×10-3mm2/s) and malignant ([1.11±0.47]×10-3mm2/s) groups (p=0.001). The threshold ADC value of ≤1.10×10-3mm2/s resulted in a sensitivity of 77.3%, a specificity of 92.9%, and an accuracy of 85.1%. A type III curve was found in 23 cases (21 malignant and two benign), a type II curve was seen in six cases (one malignant and five benign), and a type I curve in seven cases (all were benign). The SEE and slope values in the benign and malignant groups were 227.96±172.08, 325.60±125.86 (p=0.058); 0.97±0.67%/s, 3.19±3.20%/s (p=0.016), respectively. ROC analysis showed a sensitivity of 95.5%, a specificity of 85.7%, and an accuracy of 90.6% for malignancy, based on a slope cut-off value of >1.46%/s. Combining ADC and slope values resulted in a sensitivity of 100%, a specificity of 85.7%, and an accuracy of 92.9%. Both DWI and DCE-MRI showed promising results for differentiating malignant from benign bone lesions. A combination of DWI and DCE-MRI was the most valuable of the three.

Functional MRI for quantitative treatment response prediction in locally advanced rectal cancer.

Despite advances in multimodality treatment strategies for locally advanced rectal cancer and improvements in locoregional control, there is still a considerable variation in response to neoadjuvant chemoradiotherapy (CRT). Accurate prediction of response to neoadjuvant CRT would enable early stratification of management according to good responders and poor responders, in order to adapt treatment to improve therapeutic outcomes in rectal cancer. Clinical studies in diffusion-weighted imaging (DWI) and dynamic contrast-enhanced (DCE) MRI have shown promising results for the prediction of therapeutic response in rectal cancer. DWI allows for assessment of tumour cellularity. DCE-MRI enables evaluation of factors of the tumour microvascular environment and changes in perfusion in response to treatment. Studies have demonstrated that predictors of good response to CRT include lower tumour pre-CRT apparent diffusion coefficient (ADC), greater percentage increase in ADC during and post CRT, and higher pre-CRT Ktrans. However, the mean ADC and Ktrans values do not adequately reflect tumour heterogeneity. Multiparametric MRI using quantitative DWI and DCE-MRI in combination, and a histogram analysis technique can assess tumour heterogeneity and its response to treatment. This strategy has the potential to improve the accuracy of therapeutic response prediction in rectal cancer and warrants further investigation.

Evaluation of extracapsular extension in prostate cancer using qualitative and quantitative multiparametric MRI.

To investigate the value of multiparametric magnetic resonance imaging (mpMRI) for extracapsular extension (ECE) in prostate cancer (PCa). In all, 292 patients who received radical prostatectomy and underwent preoperative mpMRI at 3T were enrolled retrospectively. For determining the associations with ECE, the likelihood of ECE was assessed qualitatively on T2 -weighted imaging (T2 WI) and combined T2 WI and diffusion-weighted imaging (DWI) or dynamic contrast-enhanced imaging (DCEI). Quantitative MRI parameters were measured in PCa based on histopathological findings. Two models for detecting ECE including imaging and clinical parameters were developed using multivariate analysis: Model 1 excluding combined T2 WI and DWI and DCEI and Model 2 excluding combined T2 WI and DWI, and combined T2 WI and DCEI. Diagnostic performance of imaging parameters and models was evaluated using the area under the receiver operating characteristics curve (Az). For detecting ECE, the specificity, accuracy, and Az of combined T2 WI and DWI or DCEI were statistically better than those of T2 WI (P < 0.05), and all quantitative MRI parameters showed a statistical difference between the patients with and without ECE (P < 0.05). On multivariate analysis, significant independent markers in Model 1 were combined T2 WI and DWI, combined T2 WI and DCEI, and Ktrans (P < 0.05). In Model 2, significant markers were combined T2 WI and DWI and DCEI, Ktrans , Kep , and Ve (P < 0.05). The Az values of models 1 and 2 were 0.944 and 0.957, respectively. mpMRI may be useful to improve diagnostic accuracy of the models for determining the associations with ECE in PCa. 4 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2017;45:1760-1770.

가돌리늄 조영증강 자기공명영상과 확산강조영상의 간신경내분비종양 진단능력에 대한 비교연구

Background/Aims: To investigate the diagnostic performance of diffusion-weighted imaging (DWI) for hepatic neuroendocrine tumors (NET) compared with combined DWI and contrastenhanced magnetic resonance imaging (MRI) .MethodsFifteen patients with hepatic NET (n=128) underwent enhanced MRI and DWI with multiple-b values. We analyzed three different sets: Precontrast set; DWI set (added DWI); combined set (added enhanced image). Two reviewers rated possibility of NET using a 5-point scale for each image set. Their diagnostic performance was compared using Jackknife alternative free-response ROC (JAFROC).ResultsDiagnostic performance was better on the combined set (figure of merit [FOM]=0.852, 0.761) than the precontrast set (FOM=0.427, 0.572, P<0.05) and the DWI set (FOM=0.682, 0.620, P<0.05). However, DWI improved performance compared with precontrast set without statistical difference. In small NETs (<1 cm), all sets showed low sensitivity (10.7-65.9%) with high specificity (95.4-100%). Interobserver agreement was moderate in all image sets (k=0.521 to 0.589).ConclusionsCombined DWI and enhanced MRI were more useful for detecting NET. Although statistically insignficant, there was a trend in improved diagnostic performance with DWI.

Lymphoma and inflammation in the orbit: Diagnostic performance with diffusion-weighted imaging and dynamic contrast-enhanced MRI.

To investigate the diagnostic performance of diffusion-weighted imaging (DWI), dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI), and the combination of both in the differential diagnosis of lymphoma and inflammation in the orbit. This retrospective study was approved by the Institutional Review Board and the informed consent requirement was waived. A total of 53 patients underwent preoperative 3T MRI. Parameters of DWI and DCE MRI were evaluated in these 30 patients with orbital lymphoma and 23 patients with orbital inflammation. The diagnostic performance was evaluated using receiver operating characteristic curve analysis. Apparent diffusion coefficient (ADC) values and parameters derived from DCE MRI of orbital lymphoma and orbital inflammation differed significantly (ADC, Tmax , contrast index [CI], enhancement ratio [ER], and washout ratio [WR]: P < 0.001, P = 0.008, P < 0.001, P < 0.001, and P = 0.005 for reviewer 1, respectively; P < 0.001, P = 0.004, P < 0.001, P < 0.001, and P < 0.001 for reviewer 2, respectively). Sensitivity, specificity, and accuracy values of DWI were 76.67%, 100%, and 86.79% for reviewer 1; 70%, 95.65%, and 81.13% for reviewer 2, respectively. The combination of both were 90%, 86.96%, and 88.68% for reviewer 1; 93.33%, 78.26%, and 86.79% for reviewer 2, respectively. The combination of both was significantly superior to DWI for differentiation of orbital lymphoma from orbital inflammation (P = 0.016 for reviewer 1; P = 0.001 for reviewer 2). The combination of DWI and DCE MRI can improve diagnostic performance in differentiating lymphoma from inflammation in the orbit compared with DWI alone. 3 J. MAGN. RESON. IMAGING 2017;45:1438-1445.

Quantitative diffusion-weighted imaging and dynamic contrast-enhanced characterization of the index lesion with multiparametric MRI in prostate cancer patients.

To compare a simplified intravoxel incoherent motion (sIVIM) model to commonly used monoexponential and biexponential models in the characterization of prostate cancer (PCa) and noncancerous prostate tissues, and to investigate combinations of diffusion-weighted imaging (DWI) measures with dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI)-derived parameters in MRI-visible index lesions, to facilitate PCa risk stratification. In this retrospective, Institutional Review Board (IRB)-approved study, 43 consecutive patients with PCa who had 3T MRI exams followed by radical prostatectomy were included. DWI and DCE parameters were measured from one index lesion per patient, and noncancerous central gland and peripheral zone. Logistic regression modeling was performed to select the optimal combination of DWI and DCE measurements for tumor risk assessment. All diffusion models showed the lowest diffusion coefficients in tumors, intermediate values in noncancerous central gland, and highest values in noncancerous peripheral zone (all P < 0.001). Ktrans and kep were higher in tumors compared to central gland (P < 0.005) and peripheral zone (P < 0.001). The initial area under the contrast concentration curve was higher in tumor than the peripheral zone (P < 0.001). The area under the receiver operating characteristic curve of the combined DWI and DCE parameters (0.78) was higher than its individual components (0.73 and 0.63, respectively) for discriminating low- and intermediate-to-high-risk tumors. The sIVIM model provided comparable results with fewer b-values and shorter image acquisition time. The combination of DWI and DCE measurements of MRI-visible index lesions improved the preoperative prostate cancer risk characterization compared to the individual parameters from either technique alone. 3 J. Magn. Reson. Imaging 2017;45:908-916.

The diagnostic utility of combined diffusion-weighted imaging and conventional magnetic resonance imaging for detection and localization of non palpable undescended testes.

We aimed to evaluate the diagnostic performance of combined diffusion weighted imaging (DWI) and conventional magnetic resonance imaging (MRI), including fat-suppression T2WI for identification and localization of non palpable undescended testes (UDTs). This prospective study included 40 consecutive patients, with 47 non-palpable undescended testes (unilateral in 33 cases and bilateral in seven cases). Their age ranged from 5months to 18years, mean=7.5±5.9years. MRI examinations included T1WI, T2WI, fat-suppression T2WI and DWI at b value of 50, 400 and 800s/mm(2) . All patients underwent laparoscopic exploration. According to the laparoscopy findings, the final diagnoses of the location of UDTs were: intra-canalicular (n=18, 38%), low intra-abdominal (n=6, 13%), high intra-abdominal (n=5, 11%). Absent or vanishing testes were detected in 18 cases (38%). The diagnostic accuracy, sensitivity, specificity of combined DWI and conventional MRI were 95.7%, 93.5% and 100% respectively. Combined DWI and MRI showed a greater performance compared to conventional MRI alone for identification of non-palpable UDTs. Based on our findings, we can obviate the need for diagnostic laparoscopy in patients who had preoperative detection of inguinal testes or nubbins. However, laparoscopy is still needed to confirm an absent rather than undetected non-viable abdominal testes.

Added value of diffusion-weighted imaging to MR cholangiopancreatography for the diagnosis of bile duct dilatations.

To investigate the added value of diffusion-weighted imaging (DWI) when used with conventional T2-weighted magnetic resonance (MR) imaging (T2WI) and MR cholangiopancreatography (MRCP) for diagnosing bile duct dilatations. Our institutional review board approved this retrospective study protocol and waived the informed consent requirement. The study included 151 consecutive patients (70 men, 81 women) with intra- and/or extra-hepatic bile duct dilatation examined using MR imaging. Two radiologists independently and randomly reviewed 3 image sets (A: MRCP and T2WI; B: DWI; and C: combined T2WI, MRCP, and DWI) at different occasions to differentiate between malignancy, biliary lithiasis, and benign dilatation. The sensitivity, specificity, and diagnostic accuracy of these imaging sets were calculated and compared. For both readers, combined T2WI, MRCP, and DWI exhibited significantly higher sensitivity and diagnostic accuracy for malignant dilatation, compared with conventional T2WI and MRCP (P<0.01 for both readers). However, DWI did not significantly affect the sensitivity and diagnostic accuracy for biliary lithiasis or benign dilatation. The addition of DWI to T2WI and MRCP sequences yields significantly higher sensitivity and diagnostic accuracy when examining bile duct dilatations, particularly malignant dilatations.

Monitoring of the tumor response to nano-graphene oxide-mediated photothermal/photodynamic therapy by diffusion-weighted and BOLD MRI.

Photothermal therapy (PTT) and photodynamic therapy (PDT) are promising cancer treatment modalities. Because each modality has its own set of advantages and limitations, there has been interest in developing methods that can co-deliver the two regimens for enhanced tumor treatment. Among the efforts, nano-graphene oxide-mediated phototherapies have recently attracted much attention. Nano-graphene oxide has a broad absorbance spectrum and can be loaded with photosensitizers, such as chlorin e6, with high efficiency. Chlorin e6-loaded and PEGylated nano-graphene (GO-PEG-Ce6) can be excited at 660 nm, 808 nm, or both, to induce PDT, PTT, or PDT/PTT combination. Despite the potential of the treatments, there is a lack of a diagnostic tool which can monitor their therapeutic response in a non-invasive and prognostic manner; such an ability is urgently needed for the transformation and translation of the technologies. In this study, we performed diffusion-weighted and blood oxygenation level dependent (BOLD) magnetic resonance imaging (MRI) after GO-PEG-Ce6-mediated PTT, PDT, or PTT/PDT. We found that after efficient PTT, there is a significant increase of the tumor apparent diffusion coefficient (ADC) value in diffusion-weighted imaging (DWI) maps; meanwhile, an efficient PDT led to an increase of in BOLD images. In both the cases, the amplitude of the increase was correlated with the treatment outcomes. More interestingly, a synergistic treatment efficacy was observed when the PTT/PDT combination was applied, and the combination was associated with a greater ADC and increase than when either modality was used alone. In particular, the PTT/PDT condition that induced the most dramatic short-term increase of the ADC value (>70%) caused the most effective tumor control in the long-run, with 60% of the treated animals being tumor-free after 60 days. These results suggest the great promise of the combination of DWI and BOLD MRI as a tool for accurate monitoring and prognosis of phototherapies, which is of great value to the future developments of the methodologies.

Value of diffusion-weighted imaging combined with conventional magnetic resonance imaging in the diagnosis of thecomas/fibrothecomas and their differential diagnosis with malignant pelvic solid tumors.

BackgroundOur study aims to determine the value of diffusion-weighted imaging (DWI) combined with conventional magnetic resonance imaging (MRI) in the diagnosis of thecomas/fibrothecomas and their differential diagnosis with malignant pelvic solid tumors.MethodsIn total, 36 thecomas/fibrothecomas and 40 malignant pelvic solid tumors were included in our study. All patients underwent 1.5 T conventional MRI and DWI examinations except one patient with a fibrothecoma in whom DWI examination was not performed. The clinical features and characteristics of conventional MRI and DWI of these two groups were analyzed. Apparent diffusion coefficient (ADC) values were measured and compared between groups. Univariate analysis, multivariate logistic regression analysis, and the receiver operating characteristic curve were used for statistical analysis.ResultsAll the thecomas/fibrothecomas showed isointensity on T1 weighted imaging (T1WI) and 77.8 % (28/36) lesions showed hypo- to isointensity on T2 weighted imaging (T2WI). After administration of contrast medium, 94.4 % (34/36) tumors appeared as minor to mild enhancement. On DWI, they showed a diversity of low to very high signal intensity. All malignant pelvic masses manifested as hyperintensity on T2WI and 87.5 % (35/40) tumors showed very high signal (grade 3) on DWI. Higher area under the curve (AUC) and specificity could be achieved by using the lowest ADC value than the mean ADC value. Multivariate logistic regression analysis showed that shape, signal intensity on T2WI, capsule, and the lowest ADC value were the important indicators in discriminating thecomas/fibrothecomas from malignant pelvic solid tumors.ConclusionsThe combination of DWI and conventional MRI is of great value in the diagnosis of thecomas/fibrothecomas and their differential diagnosis with malignant pelvic solid tumors.

Uninterpretable Dynamic Susceptibility Contrast-Enhanced Perfusion MR Images in Patients with Post-Treatment Glioblastomas: Cross-Validation of Alternative Imaging Options.

PurposeThe purpose of this study was to evaluate the accuracy of diffusion-weighted imaging (DWI) and dynamic contrast-enhanced (DCE) perfusion MR imaging for distinguishing tumor recurrence from post-treatment effect as alternatives to dynamic-susceptibility contrast-enhanced (DSC) perfusion MR imaging when the DSC image is uninterpretable.Materials and MethodsThis retrospective study was approved by our institutional review board. Seventy one post-treatment glioblastoma patients who showed enlarged contrast-enhancing lesions on follow-up MR images after concurrent chemoradiotherapy and uninterpretable DSC images for corresponding enhancing lesions, underwent additional DWI and DCE MR imaging. The primary outcome was the frequency of interpretable DWI and DCE MR cases in these 71 patients. The secondary outcome was the area under the receiver operating characteristic curve (AUC) of DWI and DCE imaging parameters for distinguishing tumor recurrence from post-treatment effect in selected patients with interpretable DWI and DCE images. The imaging parameters were quantified as 10% cumulative histogram cutoff of apparent diffusion coefficient (ADC10) and 90% cumulative histogram cutoff of initial area under the time signal intensity curve (IAUC90). The AUCs were cross-validated by using leave-one-out method.ResultsOf the 71 patients, the uninterpretable DSC images were associated with treatment-related hemorrhage within the corresponding enhancing lesions (n = 54, 76.1%) and a near skull base location (n = 17, 23.9%). The frequencies of interpretable DWI and DCE image were 51 (71.8%) and 59 (83.1%) of the 71 cases with uninterpretable DSC images, respectively. Of the 45 selected patients with interpretable DWI and DCE images, the combination of DWI with DCE imaging showed a superior diagnostic performance than DWI or DCE imaging alone for differentiating tumor recurrence from post-treatment effect (cross-validated AUC: 0.78 versus 0.55 and 0.73 for reader 1; cross-validated AUC: 0.78 versus 0.53 and 0.75 for reader 2, respectively). Cross-validated accuracy of the single and combined imaging parameters also showed the highest for the combination of DWI with DCE MR imaging (72.9% for reader 1; 72.5% for reader 2) and the lowest for DWI alone (54.0% for reader 1; 56.4% for reader 2). Inter-reader agreement for DCE imaging was higher than that for DWI (intraclass correlation coefficient: 0.95 versus 0.87).ConclusionDCE MR imaging could be a superior and more reproducible imaging biomarker than DWI for differentiating tumor recurrence from post-treatment effect in patients with post-treatment glioblastoma when DSC MR images are not interpretable.

Non-model segmentation of brain glioma tissues with the combination of DWI and fMRI signals.

For quantitative analysis of glioma, multimodal Magnetic Resonance Imaging (MRI) signals are required in combination to perform a complementary analysis of morphological, metabolic, and functional changes. Most of the morphological analyses are based on T1-weighted and T2-weighted signals, called traditional MRI. But more detailed information about tumorous tissues could not be explained. An information combination scheme of Diffusion-Weighted Imaging (DWI) and Blood-Oxygen-Level Dependent (BOLD) contrast Imaging is proposed in this paper. This is a non-model segmentation scheme of brain glioma tissues in a particular perspective of combining multi-parameters of DWI and BOLD contrast functional Magnetic Resonance Imaging (fMRI). Compared with traditional MRI, a promising advantage of our work is to provide an effective and adequate subdivision of the related pathological regions with glioma, by incorporating both knowledge of image graylevel and spatial structure. Furthermore, it is an automatic segmentation method without needs of parameter selection and model fitting for the extracted tissues. By the experiments in patients with glioma, the proposed method has achieved the average overlap ratios of 83.6% in the whole tumor region and 82.5% in the peritumoral edema region with the manual segmentation as "ground truth".

Accuracy of combined dynamic contrast-enhanced magnetic resonance imaging and diffusion-weighted imaging for breast cancer detection: a meta-analysis.

Magnetic resonance imaging (MRI) is increasingly being used to examine patients with suspected breast cancer. To determine the diagnostic performance of combined dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion-weighted imaging (DWI) for breast cancer detection. A comprehensive search of the PUBMED, EMBASE, Web of Science, and Cochrane Library databases was performed up to September 2014. Statistical analysis included pooling of sensitivity and specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and diagnostic accuracy using the summary receiver operating characteristic (SROC). All analyses were conducted using STATA (version 12.0), RevMan (version 5.2), and Meta-Disc 1.4 software programs. Fourteen studies were analyzed, which included a total of 1140 patients with 1276 breast lesions. The pooled sensitivity and specificity of combined DCE-MRI and DWI were 91.6% and 85.5%, respectively. The pooled sensitivity and specificity of DWI-MRI were 86.0% and 75.6%, respectively. The pooled sensitivity and specificity of DCE-MRI were 93.2% and 71.1%. The area under the SROC curve (AUC-SROC) of combined DCE-MRI and DWI was 0.94, the DCE-MRI of 0.85. Deeks testing confirmed no significant publication bias in all studies. Combined DCE-MRI and DWI had superior diagnostic accuracy than either DCE-MRI or DWI alone for the diagnosis of breast cancer.

The value of diffusion-weighted imaging in children with acute central nervous system symptoms

The value of diffusion-weighted imaging (DWI) in children with acute central nervous system (CNS) symptoms has not been fully established. We aimed to elucidate whether DWI gives additional information in children with acute CNS disorder. The subjects were eight children with acute CNS symptoms, whose cranial DWI showed signal abnormality. Two patients were suffered from cerebral infarction, and one had systemic lupus erythematosus with CNS involvement, four had acute encephalopathy, and one had relapsing encephalopathy. We retrospectively compared (1) the size of signal abnormality, (2) latency until appearance of signal abnormality, and (3) ability to differentiate old lesions between DWI and fluid-attenuation inversion recovery (FLAIR). In addition, we analyzed cerebral blood flow (CBF) changes in lesions detected by DWI, using single-photon emission computed topography (SPECT). In seven of eight patients, the size of signal abnormality was larger in DWI compared to FLAIR. In four of five patients with magnetic resonance imaging obtained during the very acute phase of CNS symptoms, the latency until appearance of signal abnormality was shorter on DWI compared to FLAIR. Combination of DWI and FLAIR successfully differentiated new lesions from old ones in all three subjects with a history of old lesions. DWI revealed signal abnormality not during the very acute phase but on 5th day of CNS symptoms in a patient with encephalopathy. In seven patients with SPECT available, lesions detected by DWI showed decreased CBF in four patients, increased CBF in two, normal CBF in one. DWI may provide useful additional information in children with acute CNS symptoms. Signal abnormalities on DWI may represent ischemic lesions or inflammatory lesions with increased or normal CBF on SPECT.

Role of diffusion weighted imaging and contrast-enhanced MRI in the evaluation of intrapelvic recurrence of gynecological malignant tumor.

Background and PurposeTo investigate the diagnostic performance of diffusion-weighted imaging (DWI) and contrast-enhanced imaging in combination with T2-weighted imaging (T2WI) for magnetic resonance imaging (MRI) evaluation of intrapelvic recurrence of gynecological malignancies.Materials and MethodsSixty-two patients with suspected intrapelvic recurrence of gynecological malignancies underwent pelvic MRI including T2WI DWI, and contrast-enhanced imaging. Diagnostic performance for detection of local recurrence, pelvic lymph node and bone metastases, and peritoneal lesions was evaluated by consensus reading of two experienced radiologists using a 5-point scoring system, and compared among T2WI with unenhanced T1-weighted imaging (T1WI) (protocol A), a combination of protocol A and DWI (protocol B), and a combination of protocol B and contrast-enhanced imaging (protocol C). Final diagnoses were obtained by histopathological examinations, radiological imaging and clinical follow-up for at least 6 months. Receiver operating characteristic (ROC) analysis and McNemar test were employed for statistical analysis.ResultsLocally recurrent disease, lymph node recurrence, peritoneal dissemination and bone metastases were present in 48.4%, 29.0%, 16.1%, and 6.5% of the patients, respectively. The patient-based sensitivity, specificity, accuracy, and area under the ROC curve (AUC) for detection of intrapelvic recurrence were 55.0, 81.8, 64.5% and 0.753 for protocol A, 80.0, 77.3, 79.0% and 0.838 for protocol B, and 80.0, 90.9, 83.9% and 0.862 for protocol C, respectively. The sensitivity, accuracy, and AUC were significantly better for protocols B and C than for protocol A (p<0.001). There was no significant difference between protocols B and C.ConclusionMRI using a combination of DWI and T2WI gives comparatively acceptable results for assessment of intrapelvic recurrence of gynecological malignancies.

Which is the best advanced MR imaging protocol for predicting recurrent metastatic brain tumor following gamma-knife radiosurgery: focused on perfusion method.

High spatial resolution of dynamic contrast-enhanced (DCE) MR imaging allows characterization of heterogenous tumor microenvironment. Our purpose was to determine which is the best advanced MR imaging protocol, focused on additional MR perfusion method, for predicting recurrent metastatic brain tumor following gamma-knife radiosurgery (GKRS). Seventy-two consecutive patients with post-GKRS metastatic brain tumor were enrolled. Two readers independently calculated the percentile histogram cutoffs for normalized cerebral blood volume (nCBV) from dynamic susceptibility contrast (DSC) imaging and initial area under the time signal-intensity curve (IAUC) from DCE imaging, respectively. Area under the receiver operating characteristic curve (AUC) and interreader agreement were assessed. For differentiating tumor recurrence from therapy effect, adding DCE imaging to diffusion-weighted imaging (DWI) significantly improved AUC from 0.79 to 0.95 for reader 1 and from 0.80 to 0.96 for reader 2, respectively. There was no significant difference of AUC between the combination of DWI with DSC imaging and the combination of DWI with DCE imaging for both readers. With the combination of DWI and DCE imaging, the sensitivity and specificity were 86.7 and 88.1% for reader 1 and 90.0 and 85.7% for reader 2, respectively. The intraclass correlation coefficient (ICC) between readers was highest for calculation of the 90th percentile histogram cutoffs for IAUC (ICC, 0.87). Adding perfusion MR imaging to DWI significantly improves the prediction of recurrent metastatic tumor; however, the diagnostic performance is not affected by selection of either DSC or DCE MR perfusion method.