Specificity Of Diffusion-weighted Imaging Research Articles

Accuracy of diffusion-weighted imaging in differentiation between medulloblastoma and ependymoma tumors

Accuracy of diffusion-weighted imaging in differentiation between medulloblastoma and ependymoma tumors

Diagnostic accuracy of diffusion weighted imaging compared to magnetic resonance spectroscopy in differentiation of benign and malignant breast lesions: A systematic review and meta-analysis

ObjectiveTo compare the sensitivity and specificity of diffusion weighted imaging (DWI) and magnetic resonance spectroscopy (MRS) in the differentiation of benign and malignant breast lesions. MethodsScopus, PubMed, and other registries were searched up to April 2023. We included diagnostic studies with DWI and MRS as index tests and histopathologic examination as the reference standard for differentiating benign and malignant breast lesions in adult females. We excluded studies involving healthy women, only breast cancer patients, and non-comparative diagnostic accuracy studies on either index test. The sensitivity and specificity of DWI and MRS were investigated and pooled using random-effect bivariate meta-analysis. Risk of bias was assessed using QUADAS-2. Evidence quality was summarized using GRADE. ResultsEight eligible studies involving 632 females and 687 breast lesions were identified. The pooled sensitivity and specificity of DWI were 92% (CI 85–96%) and 88% (CI 75–94%), respectively. The pooled sensitivity and specificity of MRS were 85% (CI 66–94%) and 85% (CI 77–91%), respectively. No significant difference was noted in the sensitivity (7%, CI –8–22%) and specificity (3%, CI –9–14%) between DWI and MRS. ConclusionsIn low to moderate quality evidence, DWI and MRS show comparable sensitivity and specificity in differentiating benign and malignant breast lesions.

Accuracy of Diffusion Weighted Imaging in Assessment of Pelvic Lymphnode Metastasis in Patients with Endometrial Cancer.

To evaluate the sensitivity and specificity of diffusion-weighted imaging in determining metastatic pelvic lymph nodes in patients of endometrial cancer and comparing its accuracy with contrast-enhanced sequence of MRI, taking histopathology as gold standard. Retrospective Study. Place and Duration of the Study: Department of Radiology, the Aga Khan University Hospital Karachi, from January to December 2021. Fifty-eight adult females with biopsy proven endometrial carcinoma and complete medical records were included through convenience sampling. Patients who did not have complete medical records were excluded. Studied variables included signal characteristics of lymph nodes and their short axis diameter. The sensitivity and specificity of DWI and contrast-enhanced MRI for evaluation of diseased lymph nodes were calculated using histopathology as the gold standard. Among 58 patients with histopathologically proven endometrial cancer, 14 had metastatic lymphadenopathy. DWI-weighted imaging in the evaluation of metastatic and non-metastatic lymph nodes had sensitivity of 81.1% while specificity, the positive and negative predictive value of 88.8%, 72.2%, and 82.5% and on contrast-enhanced imaging as 66.6%, 58.1%, 35.7%, and 83.3%, respectively. The DWI shows better accuracy in evaluation and discrimination between metastatic and non-metastatic lymph nodes as compared to contrast-enhanced MRI examination for the evaluation of diseased lymph nodes in patients with endometrial cancer. DWI, Contrast-enhanced MRI, Lymph node, Endometrial cancer.

The Diagnostic Efficiency of Quantitative Diffusion Weighted Imaging in Differentiating Medulloblastoma from Posterior Fossa Tumors: A Systematic Review and Meta-Analysis.

Medulloblastoma (MB) is considered the most common and highly malignant posterior fossa tumor (PFT) in children. The accurate preoperative diagnosis of MB is beneficial in choosing the appropriate surgical methods and treatment strategies. Diffusion-weighted imaging (DWI) has improved the accuracy of differential diagnosis of posterior fossa tumors. Nonetheless, further studies are needed to confirm its value for clinical application. This study aimed to evaluate the performance of DWI in differentiating MB from other PFT. A literature search was conducted using databases PubMed, Embase, and Web of Science for studies reporting the diagnostic performance of DWI for PFT from January 2000 to January 2022. A bivariate random-effects model was employed to evaluate the pooled sensitivities and specificities. A univariable meta-regression analysis was used to assess relevant factors for heterogeneity, and subgroup analyses were performed. A total of 15 studies with 823 patients were eligible for data extraction. Overall pooled sensitivity and specificity of DWI were 0.94 (95% confident interval [CI]: 0.89-0.97) and 0.94 (95% CI: 0.90-0.96) respectively. The area under the curve (AUC) of DWI was 0.98 (95% CI: 0.96-0.99). Heterogeneity was found in the sensitivity (I2 = 62.59%) and the specificity (I2 = 35.94%). Magnetic field intensity, region of interest definition and DWI diagnostic parameters are the factors that affect the diagnostic performance of DWI. DWI has excellent diagnostic accuracy for differentiating MB from other PFT. Hence, it is necessary to set DWI as a routine examination sequence for posterior fossa tumors.

Radiomics based on diffusion-weighted imaging for differentiation between focal-type autoimmune pancreatitis and pancreatic carcinoma.

To evaluate the parameters of support vector machine (SVM) using imaging data generated from the apparent diffusion coefficient (ADC) to differentiate between focal-type autoimmune pancreatitis (f-AIP) and pancreatic ductal adenocarcinoma (PDAC) when using SVM based on diffusion-weighted imaging. The 2D-ADCmean and texture parameters (16 texture features × [non-filter+17 filters]) were retrospectively segmented by 2 readers in 28 patients with f-AIP and 77 patients with pathologically proven PDAC. The diagnostic accuracy of the SVM model was evaluated by receiver operating characteristic curve analysis and calculation of the area under the curve (AUC). Interreader reliability was assessed by intraclass correlation coefficient (ICC). The 2D-ADCmean and 3D-ADCmean were significantly lower in cases of f-AIP (1.10-1.15 × 10-3 mm2/s and 1.21-1.23× 10-3 mm2/s, respectively) vs PDAC (1.29-1.33 × 10-3 mm2/s and 1.41-1.43 × 10-3 mm2/s, respectively), with excellent and good interreader reliability, respectively (ICC = 0.909 and 0.891, respectively). Among the texture parameters, energy with exponential filtering yielded the highest AUC (Reader 1: 74.7%, Reader 2: 81.5%), with fair interreader reliability (ICC = 0.707). The non-linear SVM, a combination of 2D-ADCmean, object volume and exponential-energy showed an AUC value of 96.2% in the testing cohorts. Our results suggest that non-linear SVM using a combination of 2D-ADCmean, object volume, and exponential-energy may assist in differentiating f-AIP from PDAC. The radiomics based on an apparent diffusion coefficient value may assist in differentiating f-AIP from PDAC.

Diffusion-weighted image versus contrast-enhanced kinetic curves

Background and aim Noninvasive radiological techniques such as dynamic contrast-enhanced MRI (DCE-MRI) and diffusion-weighted imaging (DWI) can help distinguish between malignant and benign lesions of the breast. The current study was conducted to evaluate the diagnostic values of DCE-MRI and DWI in differentiation between benign and malignant breast lesions. Patients and methods This study was conducted on 30 patients with 32 lesions during the period from June 2019 to May 2020 at the Radiology Department and approved by the Ethics Committee. DCE-MRI and DWI were acquired for each patient using a 1.5 T machine with breast coils. Histopathological results were collected as a gold standard of the study. Results Of 32 lesions, histopathology revealed that 22 (68.75%) lesions were malignant and 10 (31.25%) lesions were benign. Mean apparent diffusion coefficient (ADC) of benign lesions was 1.25±0.56×10−3 mm2/s, which was significantly higher than those of malignant lesions (0.93±0.42×10−3 mm2/s). DWI-MRI had high sensitivity, specificity, positive predictive value, negative predictive value, and accuracy in distinguishing benign from malignant lesions (90.9, 70, 86.96, 77.78, and 84.38%, respectively). However, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of DCE-MRI were 95.5, 80, 91.3, 88.9, and 90.6%, respectively. Conclusion Compared with DWI, DCE-MRI has a higher sensitivity and specificity for distinguishing between benign and malignant lesions of the breast. Diffusion-weighted MRI provides quantitative assessment of benign and malignant lesions of the breast by measuring the ADC values.

The diagnostic performance of diffusion-weighted imaging and dynamic contrast-enhanced magnetic resonance imaging in evaluating the pathological response of breast cancer to neoadjuvant chemotherapy: A meta-analysis

PurposeTo evaluate and compare the diagnostic performance of diffusion-weighted imaging (DWI) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in predicting the pathological response of breast cancer to neoadjuvant chemotherapy (NAC). MethodsWe searched PubMed, EMBASE, Cochrane Library, and Web of Science systematically to identify relevant studies from inception to December 2020. The Quality Assessment of Diagnostic Accuracy Studies 2 tool was used to assess the methodological quality of the included studies. We extracted sufficient data to construct 2 × 2 tables and then used STATA 12.0 to perform data pooling, heterogeneity testing, meta-regression analysis and subgroup analysis. ResultsA total of 41 articles were enrolled in this study, including 27 studies (2107 patients) on DCE-MRI and 23 studies (1321 patients) on DWI. The pooled sensitivity and specificity of DCE-MRI were 0.75 and 0.79, and the pooled sensitivity and specificity of DWI were 0.77 and 0.75. There was no significant difference in sensitivity (P = 0.598) and specificity (P = 0.218) ​​between DCE-MRI and DWI. And meta-regression analysis showed that both magnetic field strength and the time of examination had significant effects on heterogeneity. ConclusionsDWI might be a potential substitute for DCE-MRI in predicting the pathological response of breast cancer to NAC as there was no significant difference in the diagnostic performance between the two. However, considering that not all included studies directly compared the diagnostic performance of DWI and DCE-MRI in the same patients and the heterogeneity of the included studies, caution should be exercised in applying our results.

Diffusion-Weighted Magnetic Resonance Imaging in the Diagnosis of Cerebral Venous Thrombosis : A Meta-Analysis.

ObjectiveA role of diffusion-weighted imaging (DWI) in the diagnosis of cerebral venous thrombosis (CVT) is not wellunderstood. This study evaluates the effectiveness of DWI in the diagnosis of CVT. MethodsLiterature search was conducted in electronic databases for the identification of studies which reported the outcomes of patients subjected to DWI for CVT diagnosis. Random-effects meta-analyses were performed to achieve overall estimates of important diagnostic efficiency indices including hyperintense signal rate, the sensitivity and specificity of DWI in diagnosing CVT, and the apparent diffusion coefficient (ADC) of DWI signal areas and surrounding tissue. ResultsNineteen studies (443 patients with 856 CVTs; age 40 years [95% confidence interval (CI), 33 to 43]; 28% males [95% CI, 18 to 38]; symptom onset to DWI time 4.6 days [95% CI, 2.3 to 6.9]) were included. Hyperintense signals on DWI were detected in 40% (95% CI, 26 to 55) of the cases. The sensitivity of DWI for detecting CVT was 22% (95% CI, 11 to 34) but specificity was 98% (95% CI, 95 to 100). ADC values were quite heterogenous in DWI signal areas. However, generally the ADC values were lower in DWI signal areas than in surrounding normal areas (mean difference−0.33×10-3 mm2/s [95% CI, −0.44 to −0.23]; p<0.00001). ConclusionDWI has a low sensitivity in detecting CVT and thus has a high risk of missing many CVT cases. However, because of its high specificity, it may have supporting and exploratory roles in CVT diagnosis.

Breast Lesion Characterisation with Diffusion Weighted Imaging Versus Dynamic Contrast Enhanced-MRI: A Prospective Observational Study in a Tertiary Care Hospital

Purpose: Dynamic contrast-enhanced (DCE)-MRI has a promising role in breast cancer detection and lesion characterisation. Diffusion-weighted imaging (DWI) acts as an adjunct in the differentiation between benign and malignant lesions. The purpose of the study was to evaluate the efficacy of DCE-MRI and DWI in differentiating benign and malignant lesions. Methods: In a prospective study conducted between March 2019 and February 2020, 60 patients with breast lesions underwent DWI combined with DCE-MRI of the breast. The time–intensity curves were plotted. Lesions were classified according to the latest American College of Radiology Breast Imaging Reporting and Data System (ACR BI-RADS; 5th edition). The results were compared with the histopathological diagnosis. The sensitivity and specificity of DWI, DCE-MRI, and combined DWI and DCE-MRI were calculated for detection of benign and malignant breast lesions. Results: Sixty patients underwent breast MRI in which 78 lesions were detected, out of which 28 were benign and 50 were malignant. Quantitative apparent diffusion coefficient measurement revealed 96% sensitivity and 82% specificity, with a positive predictive value of 92% and negative predictive value of 96%, for differentiating benign from malignant lesions. DCE-MRI findings showed 96% sensitivity and 78.5% specificity. The sensitivity of combined DWI and DCE-MRI was 98% and specificity was 86%, which was higher than DWI and DCE-MRI alone. Conclusion: Multiparametric MRI of the breast has very high sensitivity for detecting and characterising breast lesions as benign or malignant lesions. DWI had higher specificity than DCE-MRI, and the combined use of DWI and DCE-MRI had greater efficacy than DWI and DCE-MRI alone.

Diffusion weighted imaging in differentiation of the clear cell RCC from the major non-clear cell RCC subtypes

Introduction. Renal cell carcinoma (RCC) is the most common malignant renal tumor in adults accounting for 80-90% of primary malignant adult renal neoplasms. RCC represents a very heterogenous groups of tumors with a number of distinct histological varieties, of which the major 3 subtypes are clear cell RCC (70-80%), papillary RCC (13-20%), and chromophobe RCC (5%). Imaging features are varied from solid and relatively homogenous appearance to markedly heterogenous appearance with cystic changes, hemorrhage and necrosis. The use of diffusion weighted imaging (DWI) for RCC subtyping and also for differentiation of high grade and low grade tumors has been showed to be useful in many studies in the literature. Aim. In this study, we aimed to determine the comparative contribution of DWI in differentiation of the clear cell RCC from the major non-clear cell RCC subtypes at standard high b-value (1000 s/mm2) versus low b-value (500 s/mm2). In addition, we also aimed to assess the diagnostic performance of DWI for differentiating high grade clear cell RCC from low grade clear cell RCC based on Fuhrman grades in our patients. Material and methods. 62 cases with a prediagnosis of RCC according to MRI findings including DWI sequence with histological verification and subtyping of renal cortical tumor following a total or partial nephrectomy were included in the study. Results. Among 62 cases, 46 were male and 16 were female, with mean age of 59.5 ± 15.7. Pathological diagnoses of 62 cases were as follows, clear cell RCC, (44) papillary cell RCC (14) and chromophobe cell RCC (4). They were divided into two groups as clear cell RCC group (44 cases) and non-clear cell RCC group (18 cases). There was no statistically significant difference between the mean ADC values of clear cell and non-clear cell groups at b-value of 1000 s/mm2 (p&gt;0.05). However, the mean ADC level for clear cell RCC group at b-value of 500 s/mm2 were significantly higher than for non-clear cell RCC group (p&lt;0.05). When a value of 0.99x10-3 mm2/s was set as cut-off for ADC at b-factor of 500 s/mm2, differentiation was achieved with a high sensitivity (91%) and specificity (56%). Regarding the diagnostic performance of DWI for differentiating high from low Fuhrman grades clear cell RCCs, there was no statistically significant difference between the ADC values of Grade I-II clear cell RCC cases and Grade III-IV clear cell RCC cases at b-factor of 1000 s/mm2 (p&gt;0.05). However, ADC values for grade III-IV group was statistically significantly lower than ADC values for Grade I-II group at b-factor of 500 s/mm2 level. Conclusion. ADC measurements at moderate b-value of 500 s/mm2 were more sensitive in subtyping and grading of RCC cases. This technique can be used in clinical practice as a fast and additional sequence in abdominal MRI.

Qualitative and quantitative performance of diffusion-weighted imaging in differentiation between benign and malignant soft tissue lesions

IntroductionMRI is the method of choice for the diagnostic workup of soft tissue lesions. Several studies have proved the ability of diffusion-weighted imaging (DWI) and apparent diffusion coefficients (ADC) to investigate the histological features of soft tissue tumors. However, its diagnostic potential is still questionable in avoiding unnecessary invasive maneuvers like biopsy or surgery owing to some overlapping characteristics between benign and malignant lesions.ObjectiveThe study aimed to evaluate the quantitative performance of the ADC and the qualitative performance of DWI in the differentiation between benign and malignant soft tissue lesions.Patients and methodsA total of 50 patients with a histologically proof of newly diagnosed primary soft tissue tumors were retrospectively included in the study. All patients underwent MRI with DWI with sensitivities of b values (50, 400, 800, and 1000 s/mm2). ADC values of the solid components of these tumors were obtained and were correlated with the histopathological results.ResultsThe mean ADC value of the benign soft tissue lesions was 1.52 × 10−3 mm2/s, with a range of 0.4–2.6 × 10−3 mm2/s, and for the malignant soft tissue lesions was 0.78 × 10−3 mm2/s, with a range of 0.5–2.02 × 10−3 mm2/s. The cutoff of mean ADC was 0.86 × 10−3 mm2/s, which showed the highest specificity (97.22%) and accuracy (94.55%).ConclusionUsing quantitative ADC value to standard MRI can improve the diagnostic accuracy of differentiating malignant and benign soft tissue lesions. It is considered as an attractive noninvasive diagnostic tool, except for myxoid and lipid-rich neoplasms, which showed an overlap of ADC values.

Efficacy of high-resolution, 3-D diffusion-weighted imaging in the detection of breast cancer compared to dynamic contrast-enhanced magnetic resonance imaging.

PurposeTo evaluate the utility of high-resolution, 3-D diffusion-weighted imaging (DWI) in the detection of breast cancer and to compare the sensitivity, specificity, and area under the curves of DWI and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI).Material and methodProspective IEC approved study included 131 breast lesions detected on mammography and breast ultrasound. Cases underwent MRI on a 3 Tesla scanner using a dedicated breast coil. T2WI, STIR, T1WI, and dynamic post contrast MR. DWI MRI with b value of 50, 800, and 1500 s/mm2. Post-processing data with apparent diffusion coefficient (ADC) calculations and kinetic curves were obtained. Characteristics for lesions were analysed as per ACR BI-RADS descriptors. Final histopathological diagnosis was considered as the standard of reference. c2 test, t-test, receiver operating characteristic (ROC) curve analysis, pairwise comparison of ROC curves, sensitivity, specificity, diagnostic accuracy, and area under the curve (AUC) were calculated.ResultsSixty-six (50.38%) malignant and 65 (59.62%) benign lesions were included in the study. The mean ADC of malignant lesions was 0.870 × 10–3 mm2/s and 1.637 × 10–3 mm2/s (p < 0.0001) for benign lesions. Sensitivity and specificity for DWI were 95.45% and 90.76%, respectively, and for DCE-MRI they were 96.97% and 87.69%, respectively. Positive predictive value (PPV) and negative predictive value (NPV) were obtained at 91.30% and 95.16%, respectively, in DWI while in DCE-MRI they were 88.88% and 96.61%, respectively. The AUC for ADC was 0.979. In ROC comparison of AUC for DWI 0.931 and for DCE-MRI 0.923, the difference between the areas was 0.00781 (p = 0.782).ConclusionsHigh-resolution DWI is a non-contrast MRI technique, which improves the lesion detection with diagnostic performance comparable to DCE-MRI and has potential as an adjunct with screening mammography.

Multi-parametric arterial spin labeling and diffusion-weighted imaging in differentiation of metastatic from reactive lymph nodes in head and neck squamous cell carcinoma.

To assess arterial spin labeling (ASL) and diffusion-weighted imaging (DWI) in the differentiation of metastatic from reactive lymph nodes (LNs) in head and neck squamous cell carcinoma (HNSCC). Retrospective analysis of 113 LNs in 43 patients with HNSCC underwent ASL and DWI of the neck. The tumor blood flow (TBF) and apparent diffusion coefficient (ADC) of the cervical LNs were calculated. The final diagnosis of metastatic (n = 82) and reactive (n = 31) was proved with the pathological examination. The TBF of metastatic LNs (58.8 ± 10.2, 58.6 ± 8.5mL/100g/min) was significantly higher (p = 0.001) than the reactive LNs (23.2 ± 10.3, 28.2 ± 16.7mL/100g/min) for both observers, respectively. The ADC of metastatic LN (1.12 ± 0.07, 1.21 ± 0.07 × 10-3mm2/s) was significantly lower (p = 0.001) than reactive LN (1.41 ± 0.09, 1.44 ± 0.14 × 10-3mm2/s) for both observers, respectively. The threshold of TBF (> 39.5, 40.5mL/100g/min), ADC (≥ 1.31, 1.30 X10-3mm2/s) and combined parameters for both observers, respectively, used for differentiating metastatic from reactive LNs revealed an area under the curve of (0.94, 0.945), (0.90, 0.931), and (0.98, 0.989), an accuracy of (88.6%, 80.5%), (80.0%, 88.5%), and (94.3%, 98.2), respectively. Combined TBF and ADC are non-invasive imaging parameters that can play a role in differentiation metastatic from reactive LNs in patients with HNSCC.

Real-world Evidence of Diffusion-weighted Imaging Combined With Magnetic Resonance Cholangiopancreatography for Pancreatic Tumor Screening: A Cross-Sectional Diagnostic Accuracy Study.

The aim was to clarify the sensitivity and specificity of diffusion-weighted imaging, as well as of that in combination with magnetic resonance cholangiopancreatography for pancreatic tumor diagnosis in real-world clinical setting. Subjects were 217 consecutive patients who underwent both magnetic resonance imaging and contrast-enhanced ultrasound sonography. Cases positive for a pancreatic tumor were confirmed based on pathological diagnosis, whereas negative cases were defined when no solid pancreatic tumor was detected by contrast-enhanced ultrasound sonography or a solid mass was detected but the diagnosis was ultimately denied based on pathological results. Diffusion-weighted imaging-positive was defined as a case with high signals and magnetic resonance cholangiopancreatography-positive when localized main pancreatic duct stenosis with caudal dilation was detected.We calculated sensitivity and specificity of each modality and those in combination based on sequential use for pancreatic tumor diagnosis. Diffusion-weighted imaging showed a sensitivity of 94.4% and specificity of 94.5%, whereas those values for magnetic resonance cholangiopancreatography alone were 83.3% and 99.0%, respectively, and for the modalities in combination were 100% and 94.5%, respectively. Diffusion-weighted imaging was more sensitive than magnetic resonance cholangiopancreatography, whereas those used in combination resulted in increased sensitivity.

Clinical value of diffusion-weighted MRI for differentiation between benign and malignant gallbladder disease: a systematic review and meta-analysis.

Radiological differentiation between benign and malignant gallbladder disease is important but remains challenging. Furthermore, the clinical value of diffusion-weighted imaging (DWI) remains unclear. To determine the value of DWI in discriminating benign from malignant gallbladder disease by conducting a systematic review and meta-analysis. The literature was systematically searched. Studies analyzing diagnostic value of DWI in gallbladder disease with histopathology or follow-up as reference standard were included. Study selection and data extraction were done by two reviewers independently. Methodological quality was assessed using the QUADAS-2 tool. Sensitivity and specificity were calculated and displayed in a forest plot. A sensitivity analysis was performed in case of outliers. Pooled sensitivity and specificity of DWI were plotted on a hierarchical summary receiver operating characteristic curve. If available, the added value of DWI to conventional magnetic resonance imaging (MRI) sequences was analyzed. Out of 2456 articles, eight studies fulfilled the inclusion criteria; 592 patients with 221 malignant lesions were included. Pooled sensitivity and specificity rates were 0.87 and 0.84, respectively. In two studies, diagnostic accuracy rates improved after adding DWI to conventional MRI (64% and 75% for conventional MRI vs. 89% and 94% after combining conventional MRI with DWI). In another study, the area under the curve increased from 0.92 to 0.95. DWI appears to be an accurate imaging technique in discriminating benign from malignant gallbladder disease. To achieve optimal patient care, it should be part of multiparametric MRI and should be combined with other imaging modalities.

Role of diffusion-weighted imaging in differentiation between posterior fossa brain tumors

BackgroundDiffusion-weighted imaging (DWI) is an imaging modality using multi-section single-shot spin echo planar imaging (EPI) sequence which is extremely sensitive for detection of water motion within intra, extra, and transcellular regions. This character is important to differentiate between brain tumors either low (benign) or highly (malignant) cellular tumors.ObjectiveTo evaluate the role of DWI and apparent diffusion coefficient (ADC) in evaluation and differentiation between different brain posterior fossa tumors in children and adults.Patients and methodsThe study included 34 patients with different brain posterior fossa tumors for evaluation by conventional MRI (using 1.5 T MRI PHILIPS Achieva 2.1 Best Netherland) and DWI.ResultsOur study showed that mean ADC values were significantly different between the four groups of posterior fossa tumors in children: juvenile pilocytic astrocytoma (JPA), medulloblastoma, ependymoma, and brain stem glioma while mean ADC values were not significantly different between posterior fossa tumors in the adult group. Regions of interest were manually positioned, and all values were automatically calculated and expressed in 10−3 mm2/s.ConclusionDWI is an ideal additional imaging technique, which is a rapid, easy, non-invasive imaging modality, with no contrast injection needed. It has been widely applied in the differentiation between posterior fossa brain tumors and in the diagnosis of various intracranial diseases.

Role of quantitative diffusion-weighted imaging in differentiation between red and infiltrated marrow in pediatric patients with hematologic malignancy

BackgroundTo evaluate the role of DWI with ADC value measurement in the differentiation between bone marrow infiltration and normal red marrow in pediatric patients with hematologic malignanciesResultsSignificant results were obtained between ADC values of normal red and infiltrated marrow (p < 0.005). ADC values were significantly lower in infiltrative marrow lesions. The cutoff ADC value for benign and malignant lesions was 0.612 × 10−3 mm2/s.ConclusionDWI with ADC value has an additive role in differentiation between infiltrative lesions from foci of red marrow in patients with hematological malignancies.

Differentiation of benign and malignant cervical lymph nodes on MRI with special emphasis on DWI

Aim and objectives: Evaluation of cervical lymph nodes with MRI, utility of DWI in differentiation of benign and malignant cervical lymph nodes.Methods: Prospective study was carried out on 71 patients of cervical lymphadenopathy in Dr. D.Y. Patil Medical College, Hospital and Research Centre, Pimpri, Pune over a period of two years. Patients were evaluated with Siemens MAGNETOM Avanto 1.5 T MRI machine. Characteristics of cervical lymph nodes on T1WI, T2WI, STIR and Diffusion weighted images with ADC values were studied. Comparison was made with histopathological reports to study accuracy of MRI DWI in differentiating benign and malignant lymph nodes. Results: Out of the total 71 cases, 41 cases were of benign lymph nodes and 30 cases were of malignant lymph nodes. Characteristics of lymph nodes were studied on MRI. Malignant lymph nodes showed diffusion restriction with corresponding low ADC values. Mean ADC value of benign lymph nodes was 1.1×10-3mm2/s (±0.9 SD) and for malignant lymph nodes was 0.7×10-3mm2/s (±0.2 SD).The suggested ADC cut off value in our study for differentiating benign from malignant lymph nodes was to be 0.93×10-3 mm2/s. Conclusion: Diffusion weighted imaging (DWI) is an important non-invasive diagnostic method for differentiation of benign and malignant cervical lymph nodes in case of head, neck cancers.

EFFECTIVENESS OF DIFFUSION WEIGHTED MRI DERIVED METRICS IN DIFFERENTIATION OF PEDIATRIC POSTERIOR FOSSA TUMORS

Background: The value of diffusion weighted imaging (DWI) in differentiation of pediatric posterior fossa tumors (PFTs)has been established previously, however most studies were limited only to the most common types of PFTs and their results were contradictory.. Aim of work: The aim of this study was to investigate the effectiveness of DWI in differentiation of PFTs taking care to include the less frequent types, and to clarify previously reported debatable findings. Patients and methods: We retrospectively analyzed 13 embryonal tumors (EMBTs), 4 ependymomas (EPNs),8 low grade gliomas (LGGs),2 mixed neuronal glial tumors (MNGTs), and 5 diffuse intrinsic pontine gliomas (DIPGs) . For all tumors, absolutemean ADC of the non necrotic enhancing portions of the tumor and ADC ratios of the solid enhancing region of the tumor to the ADC of normal appearing cerebellum were generated. The ADC metrics of the various groups (designated according to histological subtype and WHO grade) were compared using the kruskal – wallis and student-ttests. Receiver operating characteristic (ROC) curve analysis was used to generate cutoff absolute ADC values and ADC ratios for differentiation of different types of PFTs Results: Mean ADC values and ADC ratios were significantly lower in high than in low grade tumors (P 1.108× 10−3 (100% sensitivity and 92.3% specificity)but not with mean ADC values and from LGGs using a cutoff mean ADC value of ≤ 1.333 (100% sensitivity and specificity). No statistically significant difference (P >0.05) was seen between the mean ADC values of MNGTs (1.5+/-0.02) and LGGs (1.71+/-0.13) with wide overlap in their range of ADC values and ratios.Conclusion: Apart from a few exceptions, absolute ADC values and ratios go a long way in enabling pre-operative differentiation of different types of PFTs.

Diagnostic Accuracy of Diffusion Weighted Imaging in Evaluation of High and Low Grade Pediatric Brain Tumors

AbstractBackground: Diagnosis and classification of brain tumors at pediatric age group is a challenging issue. MRI with different sequences including conventional MRI, post contrast study and diffusion weighted imaging (DWI) and well as ADC value measurement are considered accurate imaging modality to properly diagnose, classify brain lesions according to their site, extent and biological behaviour.Aim of Study: To evaluate the diagnostic accuracy of DWI in differentiation of high and low grade pediatric brain tumors.Patients and Method: Pre-operative MRI examination including; conventional MRI, post contrast study and DWI were done for 30 pediatric patients with suspected brain tumors by CT examination. Lesions evaluation regarding their size, site, signal intensity, pattern of enhancement, appearance at DWI and ADC values were done for all cases.Results: The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of diffusion weighted imaging were 89%, 100%, 100%, 86% and 93% respectively. All high grade tumors showed restricted diffusion. Post contrast MRI examination revealed no significant differ-ence between low and high grade tumors.Conclusion: Addition of DWI and ADC values measure-ment to the routine MRI examination of the brain improved the diagnostic accuracy of prediction of pediatric brain tumor histopathological grade.