Accuracy Of Diffusion-weighted Imaging Research Articles

Role of Diffusion Weighted Imaging in Localization of Non-palpable Undescended Testes Taking Laparoscopic Finding as Gold Standard

Objective: To ascertain the accuracy of diffusion-weighted imaging (DWI) in the localization of undescended testes. Material & Methods: This prospective cross-sectional study was conducted in the radiology department of a tertiary care hospital from 01-06-2022 to 15-12-2023. Total of 150 patients were included in the study. Two experienced radiologists independently examined, one observing conventional MRI alone and the other observing DWI-MRI. Following that, all of the patients underwent laparoscopic examination. The data was entered into a proforma. The findings of conventional MRI alone and DWI-MRI were correlated with laparoscopic findings. A 2 x 2 table was used to calculate the sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of DWI in comparison to laparoscopy. Results. The average age was 10.37 +/- 5.663. Conventional MRI imaging localized 50.6 % of the cases in our study, 55% of cases via DWI-MRI and 60% by laparoscopy. Sensitivity, specificity, PPV, NPV, and accuracy of conventional MRI were 72 %, 83 %, 86 %, 66 % and 76 % respectively, while for DWI-MRI was 82 %, 86 %, 93 %, 89 %, and 78 % respectively. Conclusion: The detection of undescended testes is improved by DWI-MRI. DWI-MRI is a recommended imaging tool for improving MRI's preoperative diagnostic accuracy in localization and identification of nonpalpable undescended testes.

Diagnostic accuracy of diffusion-weighted imaging and perfusion-weighted imaging with dynamic susceptibility contrast in differentiating World Health Organization Grade-I meningioma from high-grade meningioma with histopathology as gold standard

Abstract Background: Conventional magnetic resonance imaging may not be able to distinguish between the benign and malignant forms of meningioma. It has some limitations such as differentiating the grades of malignant meningioma. Diffusion-weighted imaging (DWI) and perfusion-weighted imaging (PWI) techniques can help to overcome these problems. Aims: The aim of this study was to study the diagnostic accuracy of DWI and PWI with dynamic susceptibility contrast in the differentiating World Health Organization Grade-I meningioma from high-grade meningioma with histopathology as the gold standard. Settings and Design: A hospital-based diagnostic evaluation study was carried out at the Department of Radio Diagnosis, Malla Reddy Institute of Medical Sciences, Hyderabad. Materials and Methods: Fifty cases of suspected meningioma were included in the study. The histopathology was the gold standard in this diagnostic evaluation study. DWI and PWI with dynamic susceptibility contrast results were compared against the gold standard. Statistical Analysis: Sensitivity, specificity, positive predictive value, and the negative predictive value were calculated to study the efficacy of DWI compared to histopathology as the gold standard. Results: The males (24%) were lesser than the females (76%). The female-to-male ratio was 3.2:1. The diagnostic accuracy values of apparent diffusion coefficient (ADC) with 0.6 as cutoff were sensitivity = 81.8%, specificity = 97.4%, positive predictive value = 90%, negative predictive value = 95%, and area under curve = 0.98 (95% confidence interval = 0.93–0.99) P = 0.0003. Thus, DWI using ADC with 0.6 as cutoff was found to be a very good diagnostic noninvasive tool. The diagnostic accuracy values of relative cerebral blood volume (rCBV) with 0.6 as cutoff were sensitivity = 90.5%, specificity = 98.7%, positive predictive value = 91.8%, and negative predictive value = 98.5%. Thus, DWI using rCBV with 2.52 as cutoff was found to be a very good diagnostic noninvasive tool. Conclusion: The ADC with cutoff of 0.6 and rCBV with cutoff value of 2.52 yield very good sensitivity, specificity, positive predictive value, and the negative predictive value as compared to histopathology. Hence, they can be used as noninvasive technique in differentiating Grade I meningioma from that of high-grade meningioma.

Diffusion weighted imaging with reverse encoding distortion correction: Improvement of image quality and distortion for accurate ADC evaluation in in vitro and in vivo studies

PurposeThe purpose of this in vivo study was to determine the effect of reverse encoding direction (RDC) on apparent diffusion coefficient (ADC) measurements and its efficacy for improving image quality and diagnostic performance for differentiating malignant from benign tumors on head and neck diffusion-weighted imaging (DWI). MethodsForty-eight patients with head and neck tumors underwent DWI with and without RDC and pathological examinations. Their tumors were then divided into two groups: malignant (n = 21) and benign (n = 27). To determine the utility of RDC for DWI, the difference in the deformation ratio (DR) between DWI and T2-weighted images of each tumor was determined for each tumor area. To compare ADC measurement accuracy of DWIs with and without RDC for each patient, ADC values for tumors and spinal cord were determined by using ROI measurements. To compare DR and ADC between two methods, Student’s t-tests were performed. Then, ADC values were compared between malignant and benign tumors by Student’s t-test on each DWI. Finally, sensitivity, specificity and accuracy were compared by means of McNemar’s test. ResultsDR of DWI with RDC was significantly smaller than that without RDC (p < 0.0001). There were significant differences in ADC between malignant and benign lesions on each DWI (p < 0.05). However, there were no significant difference of diagnostic accuracy between the two DWIs (p > 0.05). ConclusionRDC can improve image quality and distortion of DWI and may have potential for more accurate ADC evaluation and differentiation of malignant from benign head and neck tumors.

Role of Dynamic Magnetic Resonance Imaging in Differentiating Benign from Malignant Thyroid Nodule

Abstract Objective To determine the diagnostic accuracy of Diffusion-Weighted Imaging (DWI) and Apparent Diffusion Coefficient (ADC) in differentiating benign from malignant thyroid nodules Study Design A cross-sectional analytical study. Methodology Thirty-four patients who determined to have suspicious thyroid nodules by ultrasonography who attend endocrinology outpatient clinic at Ain-Shams university hospital, fulfilling the inclusion and exclusion criteria, were included in the study. They were evaluated on 1.5 Tesla MRI machine with T1- and T2- weighted imaging. DWI was done using b-values of 0 and 1000 s/mm2 and ADC values were calculated for the thyroid nodules. All of these patients were subjected to full history taking, general and local clinical examination, thyroid profile, TPO Abs, ultrasound, fine needle biopsy and histopathology results were correlated with ADC values. Results The benign nodules showed facilitated diffusion while malignant nodules showed restricted diffusion. T-test was used to assess the difference in mean ADC values between benign and malignant nodules. The mean ADC value of the malignant thyroid nodules (0.8±0.1 x 10-3 mm2/s) was significantly lower than that of the benign thyroid nodules (1.3±0.2 x 10-3 mm2/s) (p-value &amp;lt; 0.001). ADC value of 1.15 x 10-3 mm2/s was used as a cut-off, for differentiating benign from malignant thyroid nodules. The sensitivity, specificity, PPV, NPV and diagnostic accuracy of DWI and ADC values in differentiating benign from malignant thyroid nodules were 88.2%, 92.3%, 80%, 100% and, respectively. Conclusion FNAC is gold standard diagnostic modality but has limitations. However, DWI and (ADC) is a non-invasive diagnostic tool for characterization and differentiation between benign and malignant thyroid nodules. It decreases the burden of unnecessary surgeries when pre-operative FNAC and biopsy are inconclusive

Diagnostic performance of diffusion-weighted imaging and intravoxel incoherent motion for renal lesions: a meta-analysis

To compare the diagnostic performance of diffusion-weighted imaging (DWI) and intravoxel incoherent motion (IVIM) parameters, specifically true diffusion coefficient (D), pseudo diffusion coefficient (D∗), and perfusion fraction (f) for quantitatively differentiating benign and malignant renal lesions. A comprehensive search was conducted in the EMBASE and PubMed databases before September 2022 to identify studies in English investigating the diagnostic accuracy of DWI and IVIM in renal lesions. The quality of the included studies was assessed using the QUADAS-2 tool. Pooled sensitivity, specificity, and area under the curve (AUC) values were estimated for each parameter. A total of 19 studies involving 1,860 renal lesions (1,160 malignant and 700 benign), met the inclusion criteria. Among these studies, 15 assessed the apparent diffusion coefficient (ADC), four assessed IVIM, and three evaluated both ADC and IVIM. The pooled sensitivity, specificity, and AUC for ADC were 0.84 (95% confidence interval [Cl], 0.79-0.88), 0.82 (95% Cl, 0.72-0.89), and 0.89 (95% Cl, 0.86-0.92), respectively. The IVIM parameter with the highest diagnostic accuracy was D, with a pooled sensitivity, specificity, and AUC of 0.89 (95% Cl, 0.74-0.96), 0.96 (95% Cl, 0.85-0.99), and 0.98 (95% Cl, 0.96-0.99), respectively. The pooled sensitivity, specificity and AUC for f were 0.67 (95% Cl, 0.55-0.77), 0.81 (95% Cl, 0.30-0.98), and 0.73 (95% Cl, 0.69-0.77), respectively. The pooled sensitivity, specificity, and AUC for D∗ were 0.87 (95% Cl, 0.81-0.91), 0.59 (95% Cl, 0.48-0.70), and 0.82 (95% Cl, 0.78-0.85), respectively. This meta-analysis indicated that both IVIM and DWI had moderate to high diagnostic accuracy for differentiating benign and malignant renal lesions. Among the IVIM parameter, D exhibited the highest diagnostic accuracy, demonstrating higher sensitivity and specificity than ADC, D∗, and f.

Accuracy of Diffusion Weighted Imaging in the diagnosis and evaluation of Acute Ischemic Strokes

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

Diffusion-Weighted Imaging Combined with Perfusion-Weighted Imaging under Segmentation Algorithm in the Diagnosis of Melanoma

This study is aimed at exploring the value of magnetic resonance diffusion-weighted imaging (DWI) combined with perfusion-weighted imaging (PWI) for diagnosing melanoma under a three-dimensional (3D) hybrid segmentation algorithm. 40 patients with melanoma were collected as research objects and subjected to magnetic resonance imaging (MRI) examination. A segmentation model was constructed and the original images were input. The noise contained in the images was preprocessed and normalized, and the mixed level set segmentation was performed after linear fusion of the images. Imaging findings were analyzed to find that the combined diagnosis of DWI and PWI with a 3D hybrid segmentation algorithm had the advantage of being clear and accurate. 10 primary cases were detected, which occurred in the cerebral meninges; 30 cases of metastases occurred inside the skull, mostly adjacent to the surface of the brain. The typical T1-weighted imaging (T1WI) and T2-weighted imaging (T2WI) of melanoma showed high signal and low signal, respectively, and the enhanced scan showed obvious enhancement. Atypical melanoma was manifested variously in MRI; a few had cystic necrosis, and an enhanced scan of the solid area revealed significant enhancement. Patients with multiple metastatic melanomas mainly showed low signal on DWI, and patients with primary or single metastatic melanoma mainly showed high signal or mixed high signal. Patients with perfusion imaging showed high perfusion on PWI. The 3D hybrid segmentation algorithm helped to improve the accuracy of DWI combined with PWI in the diagnosis of melanoma. This work provided a certain reference for the clinical diagnosis of melanoma.

DWI Combined With Hepatobiliary-Phase Enhanced Imaging Can Better Differentiate Cholangiocarcinoma From Atypical Liver Abscesses

ObjectiveTo investigate the value of diffusion-weighted imaging (DWI) combined with the hepatobiliary phase (HBP) Gd-BOPTA enhancement in differentiating intrahepatic mass-forming cholangiocarcinoma (IMCC) from atypical liver abscess.Materials and MethodsA retrospective analysis was performed on 43 patients with IMCCs (IMCC group) and 25 patients with atypical liver abscesses (liver abscess group). The DWI signal, the absolute value of the contrast noise ratio (│CNR│) at the HBP, and visibility were analyzed.ResultsA relatively high DWI signal and a relatively high peripheral signal were presented in 29 patients (67.5%) in the IMCC group, and a relatively high DWI signal was displayed in 15 patients (60.0%) in the atypical abscess group with a relatively high peripheral signal in only one (6.7%) patient and a relatively high central signal in 14 (93.3%, 14/15). A significant (P<0.001) difference existed in the pattern of signal between the two groups of patients. On T2WI, IMCC was mainly manifested by homogeneous signal (53.5%), whereas atypical liver abscesses were mainly manifested by heterogeneous signal and relatively high central signal (32%, and 64%), with a significant difference (P<0.001) in T2WI imaging presentation between the two groups. On the HBP imaging, there was a statistically significant difference in peripheral │CNR│ (P< 0.001) and visibility between two groups. The sensitivity of the HBP imaging was significantly (P=0.002) higher than that of DWI. The sensitivity and accuracy of DWI combined with enhanced HBP imaging were significantly (P=0.002 and P<0.001) higher than those of either HBP imaging or DWI alone.ConclusionIntrahepatic mass-forming cholangiocarcinoma and atypical liver abscesses exhibit different imaging signals, and combination of DWI and hepatobiliary-phase enhanced imaging has higher sensitivity and accuracy than either technique in differentiating intrahepatic mass-forming cholangiocarcinoma from atypical liver abscesses.

Diffusion-Weighted Imaging Combined with Cervical Vascular Ultrasound in the Elderly Patients with Multiple Cerebral Infarction.

Objective This study is aimed at evaluating the diagnostic value of diffusion-weighted imaging combined with cervical vascular ultrasound in the elderly patients with multiple cerebral infarctions and at demonstrating whether the diagnostic value is affected by the history of diabetes. Methods From January 2020 to November 2021, the case data of 30 elderly patients with multiple cerebral infarction diagnosed in our hospital were included. Diffusion-weighted magnetic resonance imaging (DWI) and cervical vascular ultrasound (CAU) were performed, respectively. The diagnosis rates of the simple diffusion-weighted imaging group, the simple cervical vascular ultrasound group, and the diffusion-weighted imaging combined with cervical vascular ultrasound group were compared. Results The median onset time of 30 patients was 26.5 (4.75, 43.0) hours. There were 10 hyperacute patients and 20 acute patients. The proportion of diagnosable patients in the diffusion-weighted imaging group was 83.8% (25/30), which was lower than the proportion of diagnosable patients in the diffusion-weighted imaging combined with cervical vascular ultrasound group, which was 90% (27/30). The difference was statistically significant (χ2 = 16.667; P < 0.001). The ratio of diagnosable patients in the cervical vascular ultrasound group alone was 66.7% (20/30), which was lower than 90% (27/30) in the diffusion-weighted imaging combined with cervical vascular ultrasound group. The difference was statistically significant (χ2 = 6.7; P = 0.010). In the hyperacute phase, the proportion of diagnosable patients in the diffusion-weighted imaging combined with cervical vascular ultrasound group was higher than that in the diffusion-weighted imaging group alone (χ2 = 5.833; P = 0.016) and the cervical vascular ultrasound group alone (χ2 = 2.500; P = 0.004). In the acute phase, the proportion of diagnosable patients in the diffusion-weighted imaging combined with cervical vascular ultrasound group was also higher those that in the diffusion-weighted imaging group alone (χ2 = 9.474; P = 0.002) and the cervical vascular ultrasound group alone (χ2 = 3.158; P = 0.006). The diagnostic accuracy of diffusion-weighted imaging combined with cervical vascular ultrasound was not significantly different between patients with history of diabetes and without history of diabetes (χ2 = 1.014; P = 0.314) Conclusion The combined application of diffusion-weighted imaging and cervical vascular ultrasound has important value in improving the diagnosis rate of multiple cerebral infarction in the elderly, regardless of diabetes history, and it is worthy of clinical application.

To Determine the Diagnostic Accuracy of Diffusion-Weighted Imaging in the Diagnosis of Prostate Carcinoma Taking Histopathology As the Gold Standard.

IntroductionCarcinoma of the prostate is the most common malignancy among males. Serum prostate-specific antigen (PSA) levels and digital rectal examination (DRE) are the initial investigations for the detection of prostate cancer. In recent years, some investigators have used color Doppler ultrasound and diffusion-weighted imaging (DWI) for the diagnosis of prostate cancer and avoided invasive and painful investigation, i.e., biopsy. The purpose of the study is to determine the validity of DWI in detecting prostatic cancer taking histopathology as the gold standard.Material and methodsThis cross-sectional study was conducted prospectively in the radiology department of a tertiary care hospital from January 1, 2019, to December 31, 2020. This study was approved by the Departmental Research Committee. A total of 272 male patients were included in our study who have elevated PSA levels (>4.0 ng/ml) with symptoms of hematuria and urinary retention. All included subjects were sent to the radiology department for DWI imaging. The DWI imaging was analyzed for prostate cancer and the results were correlated with histopathological diagnosis.ResultsThe average age of patients was 50.28±9.93 years. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of DWI in the diagnoses of prostate cancer were 86.7%, 87.8%, 75.8%, 93.8%, and 87.5%, respectively.ConclusionDWI is an informative and non-invasive imaging modality with high diagnostic accuracy for the diagnosis of prostate carcinoma.

Feasibility of diffusion weighting with a local inside-out nonlinear gradient coil for prostate MRI.

Prostate cancer remains the second leading cancer killer of men, yet it is also a disease with a high rate of overtreatment. Diffusion-weighted imaging (DWI) has shown promise as a reliable, grade-sensitive imaging method, but it is limited by low image quality. Currently, DWI quality image is directly related to low gradient amplitudes, since weak gradients must be compensated with long echo times. We propose a new type of MRI accessory, an "inside-out" and nonlinear gradient, whose sole purpose is to deliver diffusion encoding to a region of interest. Performance was simulated in OPERA and the resulting fields were used to simulate DWI with two-compartment and kurtosis models. Experiments with a nonlinear head gradient prove the accuracy of DWI and apparent diffusion coefficient (ADC) maps encoded with nonlinear gradients. Simulations validated thermal and mechanical safety while showing a 5- to 10-fold increase in gradient strength over prostate. With these strengths, lesion contrast to noise ratio in ADC maps approximately doubled for a range of anatomical positions. Proof-of-principle experiments show that spatially varying b-values can be corrected for accurate DWI and ADC. Dedicated nonlinear diffusion encoding hardware could improve prostate DWI.

Kanser Tanısında Tüm Vucut MR ile PET-CT Karşılaştırması

Objective: Whole body diffusion-weighted imaging (DWI) has been increasingly used in oncological cases for detection and characterization of tumors and monitoring of treatment response. We compared the tumor detection capacity and diagnostic accuracy of DWI with positron emission tomography/computed tomography (PET/CT), which is regarded as the gold standard. Materials and Methods: The study included 29 adult patients (13 men and 16 women) aged between 38 and 86 years who had various types of cancer, and for whom PET/CT was indicated for staging or evaluating treatment response. A total of 240 lesions that were positive in FDG-PET/CT were identified in the DWI images, and DWI signal intensity and apparent diffusion coefficient (ADC) value were measured for each lesion. SUVmax, ADC, and DWI intensity values of PET-positive lesions and lesion areas for both methods were compared using Mann-Whitney U test and Spearman correlation test. Results: SUVmax and DWI intensities of the lesions showed significant correlation (Spearman correlation coefficient= -0.296, p&amp;lt;0.0001). When we analyzed whether lesion size was associated with SUVmax, ADC, or DWI intensity, we found a correlation between lesion diameter and DWI intensity (r=-0.30; p=0.0001). Conclusion: The DWI was generally correlated with PET/CT with very close specificity and sensitivity values between the two methods. Whole body DWI can be used as an alternative or complementary to PET/CT in investigation and follow-up of oncological cases.

Diagnostic value of thyroid micronodules with high b-value diffusion weighted imaging: Comparative study with high-resolution ultrasound

PurposeThis study aims to compare the diagnostic performance of two imaging methods for thyroid nodules ≤1.0 cm and reduce unnecessary overdiagnosis. MethodsA retrospective study was conducted on 80 patients with pathologically confirmed solitary thyroid micronodules underwent both high-resolution ultrasound (HRUS) and High b-value (2000 s/mm2) diffusion weighted imaging (DWI). Intra- and interobserver agreement (Intraclass correlation coefficient) was followed by Kruskal-Wallis test to detect whether the quantitative apparent diffusion coefficient (ADC) and thyroid nodule subgroups were related. Cohen's kappa analysis was applied to assess the interobserver consistency of DWI and HRUS characteristics. The receiver operating characteristic curves were adopted for evaluating the diagnostic performance of thyroid malignancy. The sensitivity, specificity, and accuracy of the two imaging methods were compared using the McNemar’s test and Kappa test. ResultsA total of 80 patients were included, consisting of 43 malignant and 37 benign micronodules. The sensitivity, specificity and accuracy of DWI combined with rADC (ADCmin to ADCn ratio) for the diagnosis of thyroid micronodules were 83.7%, 89.2% and 86.3%, respectively. The area under the curve (AUC) was 0.91 (95% confidence interval [CI]: 0.84–0.97). The sensitivity, specificity and accuracy of HRUS diagnosis were 100%, 62.16% and 82.5%, respectively. ConclusionHigh b-value DWI is superior to HRUS for evaluating the diagnostic performance of solid thyroid micronodules. DWI and its ADC quantitative analysis could be added to the evaluation of thyroid micronodules to improve the specificity of diagnosis, reduce overdiagnosis and avoid unnecessary biopsies or surgeries.

Diagnostic value of DWI-MRI for the detection of acute plaques in the relapse phase of multiple sclerosis

Background. The 2010 revision of the McDonald criteria, widely used for the diagnosis of multiple sclerosis (MS), has established that dissemination in time (DIT) can be demonstrated by the simultaneous presence of asymptomatic gadolinium-enhancing and non-enhancing plaques on a single magnetic resonance imaging (MRI). When the use of gadolinium contrast agents is contraindicated, diffusion-weighted imaging (DWI) is utilized to confirm diffusion alterations in active inflammatory plaques. This study intended to examine whether DWI can be a viable alternative to contrast-enhanced T1-weighted imaging for demonstrating DIT in MS. Material and methods.We assessed 30 previously diagnosed MS patients during acute relapse (based on the 2010 McDonald criteria) and evaluated their brain MRI via DWI‚ contrast-enhanced T1-weighted imaging, and FLAIR sequences. Asymptomatic plaques were defined as either hyperintense or non-hyperintense in DWI and enhancing or non-enhancing in T1GAD-MRI. Statistical indices for the prediction of plaque enhancement in T1 GAD-MRI via DWI-MRI were calculated and compared. Results. The 30 participants in our study had a total of 925 demyelinating plaques that were larger than 3mm in size and presented to be hyperintense in FLAIR-MRI. Diffusion hyperintensity and plaque enhancement were significantly correlated. The sensitivity‚ specificity, positive predictive value‚ negative predictive value, and accuracy of DWI were calculated to be 69.66%‚ 99.76%‚ 96.88%‚ 96.86%, and 96.86%, respectively. Conclusions. Hyperintense DWI findings do not necessarily overlap with contrast enhancements in T1 GAD-MRI. DWI was shown to produce a higher rate of false-positive results. Our study concludes that although T1 GAD-MRI should not be replaced by DWI to determine DIT due to its lower specificity, DWI’s continued use as a surrogate screening imaging sequence whenever the use of T1GAD-MRI is of concern is not without its merits.

Role of Diffusion-Weighted Imaging in the diagnosis of Prostatic Cancer.

Background: Magnetic Resonance Imaging (MRI) plays a vital role in diagnosing prostatic cancer routinely done before biopsy for the lesion's extent and defining the correct path for ultrasound-guided prostate biopsy. Diffusion-Weighted Imaging (DWI) is a non-invasive MRI sequence that shows improved sensitivity and specificity in the same setting with no additional cost. The study aims to evaluate the diagnostic accuracy of DWI in the detection of prostatic cancer.&#x0D; Methodology: A cross-sectional study was conducted at the radiology department of Dr. Ziauddin University Hospital between 15/ 04 /2016 to 15/ 4 /2017. A total of 201 patients who were clinically suspected of having prostatic tumors were in this study's inclusion criteria. MRI, including DWI, was done. The final diagnosis was based on an analysis of the histopathology report.&#x0D; Results: Out of 201 males with clinical suspicious of prostatic cancer, 160 were diagnosed with prostatic cancer on histopathology. Of these, 150 were positive on DWI. The sensitivity of diffusion-weighted MRI was found to be 93.7%, 75.60% specificity, and 90.0% diagnostic accuracy (DA) for the diagnosis of prostatic cancer.&#x0D; Conclusion: Diffusion-weighted sequence in MRI examination has a vital role in diagnosing prostatic cancer and should be considered a routine pre-biopsy investigation along with MRI in clinically suspected cases of prostate cancer.

Efficiency of High and Standard b Value Diffusion-Weighted Magnetic Resonance Imaging in Grading of Gliomas.

Background Glioma is the most common fatal malignant tumor of the CNS. Early detection of glioma grades based on diffusion-weighted imaging (DWI) properties is considered one of the most recent noninvasive promising tools in the assessment of glioma grade and could be helpful in monitoring patient prognosis and response to therapy. Aim This study aimed to investigate the accuracy of DWI at both standard and high b values (b = 1000 s/mm2 and b = 3000 s/mm2) to distinguish high-grade glioma (HGG) from low-grade glioma (LGG) in clinical practice based on histopathological results. Materials and Methods Twenty-three patients with glioma had DWI at l.5 T MR using two different b values (b = 1000 s/mm2 and b = 3000 s/mm2) at Al-Shifa Medical Complex after obtaining ethical and administrative approvals, and data were collected from March 2019 to March 2020. Minimum, maximum, and mean of apparent diffusion coefficient (ADC) values were measured through drawing region of interest (ROI) on a solid part at ADC maps. Data were analyzed by using the MedCalc analysis program, version 19.0.4, receiver operating characteristic (ROC) curve analysis was done, and optimal cutoff values for grading gliomas were determined. Sensitivity and specificity were also calculated. Results The obtained results showed the ADCmean, ADCratio, ADCmax, and ADCmin were performed to differentiate between LGG and HGG at both standard and high b values. Moreover, ADC values were inversely proportional to glioma grade, and these differences are more obvious at high b value. Minimum ADC values using standard b value were 1.13 ± 0.17 × 10−3 mm2/s, 0.89 ± 0.85 × 10−3 mm2/s, and 0.82 ± 0.17 × 10−3 mm2/s for grades II, III, and IV, respectively. Concerning high b value, ADCmin values were 0.76 ± 0.07 × 10−3 mm2/s, 0.61 ± 0.01 × 10−3 mm2/s, and 0.48 ± 0.07 × 10−3 mm2/s for grades II, III, and IV, respectively. ADC values were inversely correlated with results of glioma grades, and the correlation was stronger at ADC3000 (r = −0.722, P ≤ 0.001). The ADC3000 achieved the highest diagnostic accuracy with an area under the curve (AUC) of 0.618, 100% sensitivity, 85.7% specificity, and 85.7% accuracy for glioma grading at a cutoff point of ≤0.618 × 10−3 mm2/s. The high b value showed stronger agreement with histopathology compared with standard b value results (k = 0.89 and 0.79), respectively. Conclusion The ADC values decrease with an increase in tumor cellularity. Meanwhile, high b value provides better tissue contrast by reflecting more tissue diffusivity. Therefore, ADC-derived parameters at high b value are more useful in the grading of glioma than those obtained at standard b value. They might be a better surrogate imaging sequence in the preoperative evaluation of gliomas.

Accuracy of diffusion-weighted magnetic resonance imaging in evaluation of muscle invasion and histologic grading of the urinary bladder carcinoma

BackgroundCarcinoma of the urinary bladder is a common malignant tumor of the urinary tract in both men and women. Proper management of the urinary bladder cancer depends on the stage of the lesions. The aim of this prospective study was to determine the accuracy of diffusion-weighted images in early detection of muscle invasion, local tumor staging of urinary bladder carcinoma, and to measure the correlation between apparent diffusion coefficient (ADC) and histologic grade. Sixty patients with urinary bladder mass lesions underwent transurethral cystoscopy and biopsy after MR imaging. Radical cystectomy was done for lesions infiltrating muscularis propria. Different MR image sets (T2WIs, DWIs images) were interpreted; ADC values of tumors were calculated.ResultsKappa agreement was better in DWI than T2WI (Kappa was 0.756 and 0.484) and the overall agreement was (83.6% and 63.6%) among both respectively. Accuracy of DWI in diagnosis of tumor stages were 80%, 43%, 96%, and 100% while in T2WI were 55%, 43%, 74%, and 80% for T1, T2, T3, and T4 stages respectively. ANOVA test showed statistically significant difference between mean ADC values of different tumor grades.ConclusionDWI showed higher accuracy than T2WI in detection of the degree of muscle invasion of the urinary bladder carcinoma, so it can be added to the routine protocol of MRI examination especially in patients with renal impairment. ADC value can predict the histological grade of the tumor.

Juvenile Idiopathic Arthritis: Diffusion-weighted MRI in the Assessment of Arthritis in the Knee.

Background Diffusion-weighted imaging (DWI) can depict the inflamed synovial membrane in arthritis. Purpose To study the diagnostic accuracy of DWI for the detection of arthritis compared with the clinical reference standard and to compare DWI to contrast material-enhanced MRI for the detection of synovial inflammation. Materials and Methods In this institutional review board-approved prospective study, 45 participants with juvenile idiopathic arthritis (JIA) or suspected of having JIA (seven boys, 38 girls; median age, 14 years [interquartile range, 12-16 years]) were included between December 2015 and December 2018. Study participants underwent pre- and postcontrast 3.0-T MRI of the knee with an additional DWI sequence. For the clinical reference standard, a multidisciplinary team determined the presence or absence of arthritis on the basis of clinical, laboratory, and imaging findings (excluding DWI). Two data sets were scored by two radiologists blinded to all clinical data; data set 1 contained pre- and postcontrast sequences (contrast-enhanced MRI), and data set 2 contained precontrast and DWI sequences (DWI). Diagnostic accuracy was determined by comparing the scores of the DWI data set to those of the clinical reference standard. Second, DWI was compared with contrast-enhanced MRI regarding detection of synovial inflammation. Results Sensitivity for detection of arthritis for DWI was 93% (13 of the 14 participants with arthritis were correctly classified with DWI; 95% confidence interval [CI]: 64%, 100%) and specificity was 81% (25 of 31 participants without arthritis were correctly classified with DWI; 95% CI: 62%, 92%). Scores for synovial inflammation at DWI and contrast-enhanced MRI agreed in 37 of 45 participants (82%), resulting in a sensitivity of 92% (12 of 13 participants; 95% CI: 62%, 100%) and specificity of 78% (25 of 32 participants; 95% CI: 60%, 90%) with DWI when contrast-enhanced MRI was considered the reference standard. Conclusion Diffusion-weighted imaging (DWI) was accurate in detecting arthritis in pediatric participants with juvenile idiopathic arthritis (JIA) or suspected of having JIA and showed agreement with contrast-enhanced MRI. The results indicate that DWI could replace contrast-enhanced MRI for imaging of synovial inflammation in this patient group. © RSNA, 2020 Online supplemental material is available for this article.

MR diffusion versus MR perfusion in patients with ovarian tumors; how far could we get?

BackgroundOvarian tumors are one of the prevalent gynecological tumors. They are the fifth commonest tumor in women. The therapeutic strategy depends on whether the tumor is benign, borderline or malignant. They always cause nonspecific symptoms at early stages and diagnosed at advanced stages. We tried to test and compare the sensitivity and accuracy of diffusion-weighted imaging (DWI) and MR perfusion in the diagnosis of ovarian tumors among fifty patients with ovarian masses who collected after meeting the inclusion criteria depending on grayscale sonographic findings after the approval of the ethical committee of our institution. The sensitivity and accuracy of the techniques were compared.ResultsThe surgical and pathological reports of our patients proved a non-tumorous lesion in three patients. They also proved benign ovarian tumors in 18/47 (38.3%) patients, borderline tumors in 4/47 (8.5%) patients and malignant ovarian tumors in 25/47 (53.2%) patients. According to conventional MRI, ovarian tumors could be diagnosed with sensitivity 92%, specificity 61.11%, PPV 76.7%, NPV 84.6% and accuracy 79.1%. DWI and MR perfusion showed the same results where they showed sensitivity 98%, specificity 83%, PPV 90%, NPV 98% and accuracy 93% with ADC cut-off value 1 × 10−3 mm2/s.ConclusionDiffusion-weighted imaging and MR perfusion are useful in the diagnosis of ovarian tumors with approximately the same sensitivity and positive impact on operative management.

Accuracy of diffusion-weighted imaging in discriminating atypical vertebral haemangiomas from malignant masses in patients with vertebral lesions: a cross-sectional study.

PurposeVertebral haemangiomas are incidental findings in imaging modalities. Atypical haemangiomas are haeman-giomas rich in vascular tissue, and they are found to be hypointense in T1 sequences and hyperintense in T2 sequences, mimicking the findings of metastatic lesions. In the present study we aim to evaluate the ability of diffusion- weighted imaging to differentiate these two groups of vertebral lesions.Material and methodsIn the present cross-sectional study, a total of 23 lesions were included, including 10 haemangiomas and 13 malignant lesions. Diffusion-weighted imaging was used to compare atypical haemangiomas and metastatic lesions. The apparent diffusion co-efficient was determined for each lesion, and then the mean of each group was calculated. The means were then compared. Receiver operating characteristic analysis was used to determine a cut-off ADC value to differentiate these lesions.ResultsThe difference between the mean age of the two groups was not significant. The mean ADC value for atypical haemangiomas was 1884 ± 74 × 10-6 mm2/s and 1008 ± 81 × 10-6 mm2/s for the malignant lesions. The difference between the two groups was statistically significant (p < 10-3). ROC curve analysis determined an ADC value of 958 × 10-6 mm2/s to be able to differentiate between atypical haemangiomas and malignant lesions.ConclusionsDiffusion-weighted MRI could be used to differentiate between atypical haemangiomas and malignant metastatic lesions.