The Diagnostic Application of Brain Image Processing and Analysis System for Ischemic Stroke

To evaluate the added value of diffusion-weighted magnetic resonance (MR) imaging in diagnostic performance of conventional MR imaging for diagnosis of ampullary carcinoma. This retrospective study was institutional review board approved, and informed consent was waived. Twenty-three patients with malignant ampullary obstruction and 39 patients with benign ampullary obstruction were included. Qualitative (signal intensity and enhancement pattern) and quantitative (apparent diffusion coefficient [ADC]) analyses were conducted for visible or expected locations of duodenal papillae. Two observers independently reviewed conventional MR images and subsequently reviewed combined conventional and diffusion-weighted MR images. A five-point scale for likelihood of ampullary carcinoma was used. Fisher exact test and Mann-Whitney U test were used for comparing groups, and diagnostic performance (receiver operating characteristic [ROC] curve analysis), accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were evaluated. Visible or expected duodenal papillae in benign group showed isointensity (27-38 of 39, 69%-97%) and similar enhancement pattern (27 of 39, 69%) to that of normal duodenal wall more frequently than in malignant group (seven to 18 of 23 [30%-78%] and three of 23 [13%], respectively) on conventional MR images (P < .05). On diffusion-weighted images, 21 of 23 (91%) ampullary carcinomas showed hyperintensity, whereas all benign cases showed isointensity compared with normal duodenal wall (P < .001). Mean ADC of ampullary carcinomas (1.23 × 10(-3) mm(2)/sec) was significantly lower than that of benign group (1.69 × 10(-3) mm(2)/sec) (P < .001). Diagnostic performance (area under ROC curve [Az]) of both observers improved significantly after additional review of diffusion-weighted images; Az improved from 0.923 to 0.992 (P = .029) for observer 1 and from 0.910 to 0.992 (P = .025) for observer 2. In addition, diagnostic accuracy, sensitivity, specificity, PPV, and NPV of combined conventional and diffusion-weighted MR images were higher than those of conventional MR images alone. Addition of diffusion-weighted imaging to conventional MR imaging improves detection of ampullary carcinoma when compared with conventional MR imaging alone.

To retrospectively determine the value of adding perfusion-weighted (PW) and diffusion-weighted (DW) sequences to a conventional magnetic resonance (MR) imaging protocol to differentiate benign from malignant tumors. The institutional ethics committee approved this retrospective study and waived the requirement to obtain informed consent. MR images in 87 women (age range, 25-87 years) who underwent imaging before surgery for complex adnexal masses-excluding endometriomas and cystic teratomas-were analyzed. Conventional morphologic, perfusion, and diffusion MR criteria of malignancy were recorded. Three independent observers reviewed images in four steps: conventional MR images alone, conventional MR images and PW images combined, conventional MR images and DW images combined, and conventional, PW, and DW MR images combined. Receiver operating characteristic curve analysis was performed to compare the results of the readings. A recursive partitioning model was built to establish a multivariate decision tree. There was almost perfect agreement for lesion characterization regardless of the reader experiment or step considered (κ = 0.811-0.929). Area under the receiver operating characteristic curve values were higher for conventional and DW images combined, conventional and PW images combined, and conventional, DW, and PW images combined compared with conventional MR images alone (P < .05). For all readers, the accuracy of conventional, PW, and DW imaging combined was higher than that of conventional MR imaging alone for benign masses (P < .01) but not for malignant masses (P = .24). The addition of both PW and DW images led to a correct change in the diagnosis in 19% (11 of 57 patients), 23% (13 of 57 patients), and 24% (14 of 57 patients) of cases for readers 1, 2, and 3, respectively, with no incorrect changes. Conventional, PW, and DW MR imaging criteria were combined to generate a decision tree giving an accuracy of 95%. The addition of PW and DW sequences to a conventional MR imaging protocol improved the diagnostic accuracy in the characterization of complex adnexal masses.

To assess the added value of diffusion-weighted imaging (DWI) to conventional magnetic resonance imaging (MRI) for differentiating benign from malignant bile duct strictures. 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. 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. Adding DWI to conventional MRI is more helpful for differentiating benign from malignant bile duct strictures than conventional MRI alone. • 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.

Objective: To assess the accuracy of application of diffusion weighted imaging in the diagnosis and evaluation of acute onset ischemic strokes. Study Design: Cross sectional validation study. Place and Duration: Department of Diagnostic Radiology, Mardan Medical Complex, Hospital, Mardan from 15th October 2020 to 15th April 2021. Methodology: Patients whose presentation was highly suggestive of acute stroke, were undergone a non-contrast Computed tomography scan of the brain immediately by Asteion VP single slice. Those found negative for acute hemorrhage on Computed tomography images were subjected to Magnetic resonance imaging on Achieva 1.5 Tesla. Diffusion-weighted imaging technique of MRI scan was done in addition to the conventional T1W, T2W, and FLAIR scans of MRI which were also done. DWI was performed as early as possible not later than 24 hours after symptoms onset. Both DWI imaging technique and conventional routine T1W, T2W and FLAIR scans of MRI were repeated after 7 days. Results: The mean age of the sample was 57.6 + 5.9 years. On Diffusion-weighted imaging, stroke was observed in 60.2% of patients. Later on follow-up conventional magnetic resonance imaging scans were done after 7 days, stroke was recorded in 69.9% of patients confirming the diagnostic accuracy of DWI imaging in sub-acute stroke in early diagnosis. Conclusion: Conventional MRI scans like T1W, T2W and FLAIR have diagnostic accuracy only after some days. It has poor diagnostic accuracy in early onset sub-acute ischemic strokes. On the other hand, DWI imaging scans of MRI can be a useful tool for early detection of ischemic strokes as it diagnosed stroke in 60.2% of patients which were later confirmed by conventional MRI scans done after 7 days. Conventional MRI scans have high accuracy of detection of strokes but only after some days. So DW1 imaging may be applied for early diagnosis of strokes in sub-acute onset strokes. Keywords: Ischemic stroke, Magnetic Resonance Imaging, Diffusion Weighted Imaging, Hemorrhage, Computed Tomography How to Cite This: Afridi SQ, Baig H, Janan Z, Begum T, Shuaib M. Accuracy of diffusion-weighted imaging in the diagnosis and Evaluation of acute ischemic strokes. Isra Med J. 2022; 14(3): 99-103. DOI: https://doi.org/10.55282/imj.oa1314

Upper abdominal gadoxetic acid-enhanced and diffusion-weighted MRI for the detection of gastric cancer: Comparison with two-dimensional multidetector row CT

ObjectiveTo assess the feasibility of ultrafast brain magnetic resonance imaging (MRI) in pediatric patients.Materials and MethodsWe retrospectively reviewed 194 pediatric patients aged 0 to 19 years (median 10.2 years) who underwent both ultrafast and conventional brain MRI between May 2019 and August 2020. Ultrafast MRI sequences included T1 and T2-weighted images (T1WI and T2WI), fluid-attenuated inversion recovery (FLAIR), T2*-weighted image (T2*WI), and diffusion-weighted image (DWI). Qualitative image quality and lesion evaluations were conducted on 5-point Likert scales by two blinded radiologists, with quantitative assessment of lesion count and size on T1WI, T2WI, and FLAIR sequences for each protocol. Wilcoxon signed-rank tests and intraclass correlation coefficient (ICC) analyses were used for comparison.ResultsThe total scan times for equivalent image contrasts were 1 minute 44 seconds for ultrafast MRI and 15 minutes 30 seconds for conventional MRI. Overall, image quality was lower in ultrafast MRI than in conventional MRI, with mean quality scores ranging from 2.0 to 4.8 for ultrafast MRI and 4.8 to 5.0 for conventional MRI across sequences (P < 0.001 for T1WI, T2WI, FLAIR, and T2*WI for both readers; P = 0.018 [reader 1] and 0.031 [reader 2] for DWI). Lesion detection rates on ultrafast MRI relative to conventional MRI were as follows: T1WI, 97.1%; T2WI, 99.6%; FLAIR, 92.9%; T2*WI, 74.1%; and DWI, 100%. The ICC (95% confidence interval) for lesion size measurements between ultrafast and conventional MRI was as follows: T1WI, 0.998 (0.996–0.999); T2WI, 0.998 (0.997–0.999); and FLAIR, 0.99 (0.985–0.994).ConclusionUltrafast MRI significantly reduces scan time and provides acceptable results, albeit with slightly lower image quality than conventional MRI, for evaluating intracranial abnormalities in pediatric patients.

Diffusion-weighted imaging provides a novel contrast mechanism in magnetic resonance (MR) imaging and has a high sensitivity in the detection of changes in the local biologic environment. A significant advantage of diffusion-weighted MR imaging over conventional contrast material-enhanced MR imaging is its high sensitivity to change in the microscopic cellular environment without the need for intravenous contrast material injection. Approaches to the assessment of diffusion-weighted breast imaging findings include assessment of these data alone and interpretation of the data in conjunction with T2-weighted imaging findings. In addition, the analysis of apparent diffusion coefficient (ADC) value can be undertaken either in isolation or in combination with diffusion-weighted and T2-weighted imaging. Most previous studies have evaluated ADC value alone; however, overlap in the ADC values of malignant and benign disease has been observed. This overlap may be partly due to selection of b value, which can influence the concomitant effect of perfusion and emphasize the contribution of multicomponent model influences. The simultaneous assessment of diffusion-weighted and T2-weighted imaging data and ADC value has the potential to improve specificity. In addition, the use of diffusion-weighted imaging in a standard breast MR imaging protocol may heighten sensitivity and thereby improve diagnostic accuracy. Standardization of diffusion-weighted imaging parameters is needed to allow comparison of multicenter studies and assessment of the clinical utility of diffusion-weighted imaging and ADC values in breast evaluation.

Objective: To assess the evidence for the use of diffusion-weighted imaging (DWI) and perfusionweighted imaging (PWI) in the diagnosis of patients with acute ischemic stroke. Methods: We systematically analyzed the literature from 1966 to January 2008 to address the diagnostic and prognostic value of DWI and PWI. Results and Recommendations: DWI is established as useful and should be considered more useful than noncontrast CT for the diagnosis of acute ischemic stroke within 12 hours of symptom onset. DWI should be performed for the most accurate diagnosis of acute ischemic stroke (Level A); however, the sensitivity of DWI for the diagnosis of ischemic stroke in a general sample of patients with possible acute stroke is not perfect. The diagnostic accuracy of DWI in evaluating cerebral hemorrhage is outside the scope of this guideline. On the basis of Class II and III evidence, baseline DWI volumes probably predict baseline stroke severity in anterior territory stroke (Level B) but possibly do not in vertebrobasilar artery territory stroke (Level C). Baseline DWI lesion volumes probably predict (final) infarct volumes (Level B) and possibly predict early and late clinical outcome measures (Level C). Baseline PWI volumes predict to a lesser degree the baseline stroke severity compared with DWI (Level C). There is insufficient evidence to support or refute the value of PWI in diagnosing acute ischemic stroke (Level U). Neurology ® 2010;75:177–185

To investigate diffusion-weighted (DW) magnetic resonance (MR) imaging for differentiating borderline from malignant epithelial tumours of the ovary. This retrospective study included 60 borderline epithelial ovarian tumours (BEOTs) in 48 patients and 65 malignant epithelial ovarian tumours (MEOTs) in 54 patients. DW imaging as well as conventional MR imaging was performed. Signal intensity on DW imaging was assessed and apparent diffusion coefficient (ADC) value was measured. The results were correlated with histopathology and cell density. The majority of MEOTs showed high signal intensity on DW imaging, whereas most BEOTs showed low or moderate signal intensity (P = 0.000). The mean ADC value of the solid components in BEOTs (1.562 ± 0.346 × 10(-3) mm(2)/s) was significantly higher than in MEOTs (0.841 ± 0.209 × 10(-3) mm(2)/s). A threshold value of 1.039 × 10(-3) mm(2)/s permitted the distinction with a sensitivity of 97.0%, a specificity of 92.2% and an accuracy of 96.4%. There was an inverse correlation between ADC value and cell density (r = -0.609; P = 0.0000) which was significantly lower in BEOTs than in MEOTs. DW imaging is useful for differentiating borderline from malignant epithelial tumours of the ovary. DW MR imaging is useful for differentiating BEOTs from MEOTs. Patients with BEOTs are treated differently from patients with MEOTs. Conservative fertility-sparing laparoscopic surgery can be performed in patients with BEOTs. BEOTs often affect young women of childbearing age.

Introduction: The conventional magnetic resonance imaging (MRI) method is widely considered ‘with limited success’ in differentiating the meningioma types but may fail to localize the tumor occupation of white-matter fiber bundles accurately. Diffusion tensor imaging (DTI) is considered as an imaging modality that may elucidate the microstructure of brain tumors. We provide characteristics of meningioma using DTI-based-three-dimensional tracing of white matter to portray meningioma in a noninvasive approach and its structural contact to contiguous tumors and elucidate the influence of occupying lesions on white-matter fiber bundles. Case Presentation: A 28-year-old female presented with visuospatial disturbances and persistent headaches for 2 years. Conventional and advanced MRI studies were performed. Diffusion-weighted Images (DWI) and Apparent Diffusion Coefficient (ADC) values were measured in the lesion using routine MRI sequences. Advanced MRI using DTI was also performed. Conventional MRI outcomes showed tumor parenchyma, peritumoral edema, and compression on the circumnavigated brain tissue. There was hyperintense on DW trace image and isointense on ADC map. On T2-weighted image (T2WI) and Fluid-Attenuated Inversion Recovery (FLAIR) images, there was an increased signal intensity that demonstrated an extra-axial lesion, while T1-weighted imaging signals showed hypointensity. DTI fractional anisotropy (FA) marker is an unclear optic radiation in the concerned area, indicating the shift or destruction of the optic radiation. The mean FA values of solid-enhancing areas of meningioma were 0.28 ± 0.17. Mean ADC values (103 mm2/s) were 0.764 ± 0.172. Conclusions: Classic meningioma in this case has low intratumoral FA and high ADC. DTI displayed that intratumoral microscopic water motion is disorganized.

To establish the supplemental value of diffusion-weighted (DW) magnetic resonance (MR) imaging beyond conventional MR to predict clinical outcome after neonatal hypoxic ischemia (HI) at 2 years of age. Forty-six infants with neonatal HI were enrolled in this prospective study, after approval by the local ethical committee and informed consent of the parents. Neonatal MR imaging ranged from 1 to 45 days after birth. Apparent diffusion coefficient (ADC) was measured in 14 brain regions. DW and conventional images were qualitatively scored for abnormalities, resulting in cumulative scores and patterns of damage. Surviving infants were scored for motor outcome at the age of 2 years, and outcome was classified as poor if the motor score was less than 70 or in case of death. Analyses were performed for the whole group, with additional analyses for the early (0-4 days after birth) and late (>4 days after birth) imaging groups. Twenty-five infants had a good outcome and 21 had a poor outcome. Only in the early imaging group, the infants with poor outcome had significantly lowered ADC values in several brain areas, with the posterior limb of the internal capsule being the most predictive (Wald score = 5.7; P = .017). Cumulative scores of DW imaging were the best predictor of poor motor outcome at the age of 2 years (Wald score = 7.2, P < .01). The basal ganglia and central cortex and the diffuse pattern of brain damage were highly associated with poor outcome (Fisher exact test = 29.8; P < .001). In neonatal HI, DW imaging is a useful additional MR technique to predict the motor outcome at 2 years. Local ADC values had a limited value. Recognition of the patterns of brain damage with DW and conventional MR imaging can be used as a diagnostic tool in neonatal HI.

See related article, pages 1826–1830. The goal of acute stroke evaluation is to determine not only stroke type (ischemic versus hemorrhagic) and localization (anatomical and vascular), but perhaps more importantly, to determine reversibility (presence of an ischemic penumbra that may be salvaged with acute therapy). Traditionally, neurologists have relied on history and neurological examination to provide much of this information. However, long experience has demonstrated that the neurological examination is imperfect at best in determining lesion localization and grossly limited in its ability to provide insights into the presence of penumbral tissue. This is evidenced by the only modest correlations between National Institutes of Health Stroke Scale (NIHSS) score and perfusion-weighted imaging lesion volume.1,2 The last decade has seen a striking growth in neuroimaging techniques that provide important real-time information about acute stroke pathophysiology. In the mid-1990s the advent of diffusion-weighted imaging revolutionized the role of MRI in acute stroke evaluation. Not …

Applications of DWI in clinical neurology

Circulating MicroRNAs as Novel Potential Biomarkers for Early Diagnosis of Acute Stroke in Humans

Gastrointestinal stromal tumours: Correlation of modified NIH risk stratification with diffusion-weighted MR imaging as an imaging biomarker