Average Apparent Diffusion Coefficient Values Research Articles

Mediastinal lymphadenopathy in sarcoidosis: Can diffusion MRI play a role in its evaluation?

BackgroundSarcoidosis is a multisystem disease defined by non-caseous epithelioid cell granulomas that can affect virtually all organs. Lung, mediastinal and hilar lymph node involvement is prevalent, occurring in around 90% of the patients, and is responsible for the majority of the morbidity and mortality related to the disorder. Sarcoidosis is one of the differential diagnoses of the benign mediastinal lymphadenopathy. This research aimed to detect the diagnostic value of magnetic resonance imaging (MRI) diffusion in evaluation of mediastinal lymphadenopathy in sarcoid patients.ResultsThis cross study involved a total of 30 patients known to have sarcoidosis: 6 males and 24 females aged between 18 and 50 years (with a mean age 38.97 ± 8.67); all of them presented with mediastinal lymphadenopathy. For all patients, each lymph node group was evaluated for the average size and average ADC value. The mean ADC measured was (1.76 ± 0.28) × 10−3 mm2/s. Eight patients showed concurrent activity with poor response to the treatment, and they showed different ADC values with one of them showing low ADC with pattern of diffusion restriction displaying mean ADC value of 1.28 × 10−3 mm2/s.ConclusionsDiffusion-weighted MRI is an established imaging technique that could be utilized to evaluate mediastinal lymphadenopathy in sarcoidosis as the benign counterpart of mediastinal lymphadenopathy.

Usefulness of apparent diffusion coefficient values for distinguishing between squamous cell carcinoma and malignant salivary gland tumor of the head and neck.

The aim of the study was to assess the usefulness of apparent diffusion coefficient (ADC) values for differentiating between SCC and malignant salivary gland tumors of the head and neck. This retrospective cross-sectional study was conducted on 29 patients with SCCs and 10 patients with malignant salivary gland tumors who underwent pretreatment MRI of the head and neck. The minimum and average ADC values of the tumors were measured, with normalized tumor to spinal cord ADC ratios generated. Comparisons of ADC values and normalized ADC ratios between the two tumor types were performed using the unpaired t-test. The minimum and average ADC values and normalized average ADC ratios of SCCs (753.17 ± 214.47 × 10-6mm2/s, 848.79 ± 250.13 × 10-6mm2/s, and 0.92 ± 0.25, respectively) were significantly lower than those of malignant salivary gland tumors (1084.90 ± 242.60 × 10-6mm2/s, 1305.90 ± 270.99 × 10-6mm2/s, and 1.58 ± 0.31, respectively; all p < 0.001). A cutoff value of 1.31 for the normalized average ADC ratio was used to distinguish between SCCs and malignant salivary gland tumors and achieved an area under the curve of 0.93, sensitivity of 96.6%, specificity of 90%, and accuracy of 94.6%. ADC value measurement could help differentiate between SCCs and malignant salivary gland tumors.

The role of diffusion-weighted imaging in the diagnosis of early kidney damage

Objective: This study aimed to determine a threshold value for distinguishing early-stage chronic kidney disease (CKD) from moderate and advanced stages as well as patients with early-stage CKD from those with normal renal function using apparent diffusion coefficient (ADC) and normalized ADC values. Methods: This retrospective study enrolled 257 patients. Diffusion-weighted images were obtained with a set of b = 50,400,800 values. In each patient, six ADC values were measured from upper, middle, and lower areas of both kidneys, and three ADC values were measured from the spleen. Patients with CKD were classified into five subgroups and healthy patients were classified into two subgroups according to their glomerular filtration rate (GFR). Results: The renal ADC values were found to be positively correlated with GFR (r = 0.790, p &amp;lt; 0.001) and negatively correlated with creatinine levels (r = −0.709, p &amp;lt; 0.001). The mean ADC values of the stage 1 and 2 CKD groups were found to be significantly higher than those of advanced-stage CKD groups (p &amp;lt; 0.001), and these values were significantly lower in the stage 1 and 2 CKD groups than in the healthy group (p &amp;lt; 0.001). With a cut-off value of ≥1.791 for ADC, the sensitivity was 76.5% and the specificity was 85% while distinguishing between patients with early- and advanced-stage CKD. Conclusion: Renal and normalized ADC values are strongly correlated with CKD stages, and with the use of appropriate threshold values, the difference between early and advanced stages of CKD can be predicted.

Peritumoral ADC Values Correlate with the MGMT Methylation Status in Patients with Glioblastoma

Different results have been reported concerning the relationship of the apparent diffusion coefficient (ADC) values and the status of methylation as the promoter gene for the enzyme methylguanine-DNA methyltransferase (MGMT) in patients with glioblastomas (GBs). The aim of this study was to investigate if there were correlations between the ADC values of the enhancing tumor and peritumoral areas of GBs and the MGMT methylation status. In this retrospective study, we included 42 patients with newly diagnosed unilocular GB with one MRI study prior to any treatment and histopathological data. After co-registration of ADC maps with T1-weighted sequences after contrast administration and dynamic susceptibility contrast (DSC) perfusion, we manually selected one region-of-interest (ROI) in the enhancing and perfused tumor and one ROI in the peritumoral white matter. Both ROIs were mirrored in the healthy hemisphere for normalization. In the peritumoral white matter, absolute and normalized ADC values were significantly higher in patients with MGMT-unmethylated tumors, as compared to patients with MGMT-methylated tumors (absolute values p = 0.002, normalized p = 0.0007). There were no significant differences in the enhancing tumor parts. The ADC values in the peritumoral region correlated with MGMT methylation status, confirmed by normalized ADC values. In contrast to other studies, we could not find a correlation between the ADC values or the normalized ADC values and the MGMT methylation status in the enhancing tumor parts.

Should PI-RADS 3 be Subclassified According to ADC Values in the Transition Zone?

The premise of this paper starts from the fact that a more precise definition related to the intensity of the lesions on the ADC sequence can lead to a new subclassification of PI-RADS 3 lesions in the transitional zone and to an improvement of the specificity of the PI-RADS classification. The study was retrospective and included only patients who, based on prostate MRI examinations, contained exclusively PI-RADS 3 lesions, without other PI-RADS 4 or 5 lesions. The number of cases that meet all these conditions was reduced to 18, where a series of characteristics were noted for each one: PI-RADS 3 lesion area on the ADC sequence, the minimum and average ADC value of the lesion, the average ADC value of the transitional zone outside the lesion, PSA, prostatic volume, PSA density and biopsy result. The average ADC value of the negative lesions was 865(165) m2/sec, and of the positive ones was 869(118) m2/sec, which denies the hypothesis that there could be a value limit ADC to delimit PI-RADS 3 from PI-RADS 2 or 4 in this sample of patients. Furthermore, we reported the average ADC value of each such lesion to the adjacent unchanged transitional zone and obtained a greater difference of 432(163) m2/sec between the negative lesions and their adjacent transitional zone, compared to the difference of 399(127) m2/sec between the positive lesions and their adjacent ones.

Clinical Evaluation of High-Resolution MRI Combined With DWI in Identifying Vulnerable Carotid Plaque.

High-resolution magnetic resonance imaging combined with diffusion weighted imaging is used to identify vulnerable plaques (VP) and their characteristic components, and apparent diffusion coefficient (ADC) correlation analysis with serum inflammatory markers to assess plaque vulnerability. In this study, 60 eligible patients were included, including 29 patients in VP group and 31 patients in non-VP group (N group). The average ADC value, serum inflammatory marker levels (high-sensitivity C-reactive protein, myeloperoxidase, and erythrocyte sedimentation rate) of the 2 groups were measured, and the characteristics of different plaque components and ADC levels of vascular wall in VP group were compared, to evaluate the correlation between serum inflammatory markers and the mean value of plaque ADC. The results showed that the ADC mean value of the plaques in the VP group was significantly lower than that in the N group, and the levels of hypersensitive C-reactive protein and myeloperoxidase were correlated with the ADC mean value of the plaques. The ADC value of plaque measured by high-resolution magnetic resonance imaging combined with diffusion weighted imaging sequence can quantify the identification of VP and its characteristic components, reflect the inflammation of plaque to a certain extent, and thus prevent and treat stroke and other adverse outcomes more effectively.

Can diffusion-weighted imaging be used in the examination of peritoneal fluids?

The aetiology of free fluid detected in the abdomen can be investigated with magnetic resonance imaging (MRI). The aim of this study is to investigate the effectiveness of diffusion-weighted images (DWI) and apparent diffusion coefficient (ADC) values in the evaluation of abdominopelvic fluids. Patients with abdominopelvic fluid detected on MRI of the lower abdomen were included in this retrospective, single-centre study. Paracentesis and fluid analysis was performed in these patients. The average ADC values in fluids were measured by a radiologist. A cut-off value was determined, and the specificity, sensitivity, negative predictive value (NPV), and positive predictive values (PPV) were calculated. Intra-observer agreement was investigated. The study comprised 41 (33 female) patients, and their mean age was 48 ± 4.02 years. The ADC values in infective fluids were significantly higher than in non-infective fluids (p < 0.001). The cut-off value used was 2.95 × 10-3 mm2/s. According to this threshold value, sensitivity in distinguishing non-infective from infective fluids was 88%, specificity was 93.8%, PPV was 95.7%, and NPV was 83.3%. Intra-observer agreement was strong in ADC values (κ = 0.699) (p < 0.001). We concluded that the ADC value is a non-invasive, reliable, reproducible imaging parameter that can be useful in the evaluation and characterization of abdominal fluids.

Magnetic resonance imaging diagnosis of renal infection in children

OBJECTIVE: To analyze the magnetic resonance imaging (MRI) manifestations of renal infection in children, evaluate the reliability of diffusion-weighted imaging (DWI) in detecting renal infections, and the difference in apparent diffusion coefficient (ADC) values between acute renal pelvis nephritis (APN), acute focal bacterial nephritis (AFBN) and renal abscess (RA). METHODS: Data for 513 children with a clinical orpathological diagnosis of acute kidney infection. Both MRI and voiding cystourethrography were performed in 28 cases. Group A comprised 17 cases of retrograde infection; Group B comprised 11 cases of blood–borne infection. The Kappa test was used to analyze differences in lesion DWI distribution between the groups, and the t-test was used to compare the ADC values. RESULTS: The MRI manifestations of pediatric renal infection were characteristic. The lesions had high-signal intensity on DWI and were located mainly in the renal cortex blood–borne infections versus the renal cortex and medulla in retrograde infections. The sensitivity and specificity of DWI for detecting lesions were 100% and 96%. The average ADC values of APN, AFBN, and RA lesions were lower than that of normal kidney tissue, with statistically significant differences between the three conditions; the ADC value of RA was the lowest, and that of APN was the highest. CONCLUSION: There were differences in the lesion distributions between renal retrograde and blood–borne infections. The quantitative decrease in ADC value may be related to the duration of the disease and the degree of renal damage.

Meningioma: Is apparent diffusion coefficient value of any importance? A study from the tertiary care center

Objectives: Meningiomas are one of the most common intracranial tumors accounting for 14–20% of all intracranial tumors. Diffusion-weighted imaging (DWI) along with the calculation of apparent diffusion coefficient (ADC) is a novel, non-invasive, and reliable technique of choice for the pre-operative assessment and the treatment planning of different types of meningiomas. Our study aimed to correlate the ADC values of meningiomas with their histopathological grade. Materials and Methods: We studied 21 patients with meningioma. These were initially diagnosed on imaging and confirmed on histopathology. We calculated the normalized ADC (NADC) values from the DWI of their lesion. NADC values and atypical morphological features were utilized to type the meningiomas as typical or atypical. These findings were correlated with histopathological reports of grading of meningioma. Results: There was no significant correlation between the grades of meningioma and the ADC values. The normalized ADC values varied from 0.14 to 1.37 × 10−3 mm2/s for Gr I meningioma in our series and most of our cases fell in this category of meningioma. We had a solitary case of Gr-II meningioma and the ADC value for this lesion was 1.26 × 10−3 mm2/s. Conclusion: Meningiomas are a common group of tumors in the brain with a quest to characterize the grades preoperatively on imaging. The NADC is a better method as compared to plain ADC values for this purpose. In our series, we did not find any correlation of NADC on pre-operative imaging to the grades of tumors.

MRI comparative study of diffuse midline glioma, H3 K27-altered and glioma in the midline without H3 K27-altered

PurposeThe MRI features of Diffuse midline glioma, H3 K27-altered and glioma in the midline without H3 K27-altered were compared and analyzed, and the changes in the apparent diffusion coefficient (ADC) of the two groups were quantitatively analyzed.MethodsThe MRI images of 35 patients with Diffuse midline gliomas, H3 K27-altered and gliomas in the midline without H3 K27-altered were analyzed retrospectively. The location, edge, signal, peritumoral edema and enhancement characteristics of the lesions were observed, and the changes in ADC values were analyzed.ResultsIn the H3 K27-altered group, 85.7% (12/14) of the tumors were located in the thalamus and brainstem compared with 28.6% (6/21) in the no H3 K27-altered group. In the H3 K27-altered group, for tumors only located in the midline area, only 14.3% (1/7) had irregular shapes and unclear boundaries, while for tumors also invaded the extramidline tissues 85.7% (6/7) had irregular shapes and unclear boundaries.The"basilar artery wrapped sign” was found in 6 patients with tumors located in the pons in the H3 K27-altered group, but none in the no H3 K27-altered group had this sign. In the H3 K27-altered group, only 14.3% (1/7) of the tumors confined to the midline area had small cystic degeneration and necrosis, while for tumors also invaded the extramidline tissues, 100% (7/7) of the tumors had cystic degeneration and necrosis, and the cystic degeneration and necrosis only located in the extramidline region of the tumor in 6 cases.A total of 78.6% (11/14) of tumors in the H3 K27-altered group showed mild to moderate enhancement, while 47.6% (10/21) of tumors in the no H3 K27-altered group showed mild to moderate enhancement. The average peritumoral edema index was 1.13 in the H3 K27-altered group and 1.75 in the no H3 K27-altered group. The average ADC value of tumor in the H3 K27-altered group was 7.83 × 10− 4 mm2/s, and the ratio to normal brain tissue was 0.844, while the values in the no H3 K27-altered group were 13.5 × 10− 4 mm2/s and 1.75, respectively.ConclusionCompared with gliomas in the midline without H3 K27-altered, The MRI findings and ADC value of Diffuse midline gliomas, H3K27-altered have some characteristics, which can help improve the diagnosis and differential diagnosis.

Dynamic Contrast-Enhanced MRI Parameters and Normalized ADC Values Could Aid Differentiation of Skull Base Osteomyelitis from Nasopharyngeal Cancer.

The skull base osteomyelitis sometimes can be difficult to distinguish from nasopharyngeal cancer. This study aimed to investigate the differences between skull base osteomyelitis and nasopharyngeal cancer using dynamic contrast-enhanced MR imaging and normalized ADC values. This study included 8 and 12 patients with skull base osteomyelitis and nasopharyngeal cancer, respectively, who underwent dynamic contrast-enhanced MR imaging and DWI before primary treatment. Quantitative dynamic contrast-enhanced MR imaging parameters and ADC values of the ROIs were analyzed. Normalized ADC parameters were calculated by dividing the ROIs of the lesion by that of the spinal cord. The rate transfer constant between extravascular extracellular space and blood plasma per minute (Kep) was significantly lower in patients with skull base osteomyelitis than in those with nasopharyngeal cancer (median, 0.43 versus 0.57; P = .04). The optimal cutoff value of Kep was 0.48 (area under the curve, 0.78; 95% CI, 0.55-1). The normalized mean ADC was significantly higher in patients with skull base osteomyelitis than in those with nasopharyngeal cancer (median, 1.90 versus 0.87; P < .001). The cutoff value of normalized mean ADC was 1.55 (area under the curve, 0.96; 95% CI, 0.87-1). The area under the curve of the combination of dynamic contrast-enhanced MR imaging parameters (Kep and extravascular extracellular space volume per unit tissue volume) was 0.89 (95% CI, 0.73-1), and the area under the curve of the combination of dynamic contrast-enhanced MR imaging parameters and normalized mean ADC value was 0.98 (95% CI, 0.93-1). Quantitative dynamic contrast-enhanced MR imaging parameters and normalized ADC values may be useful in differentiating skull base osteomyelitis and nasopharyngeal cancer. The combination of dynamic contrast-enhanced MR imaging parameters and normalized ADC values outperformed each measure in isolation.

Quantitative analysis of age-related changes in cervical lymph nodes using diffusion-weighted imaging

ObjectivesThis study aimed to investigate age-related changes in apparent diffusion coefficient (ADC) values of cervical lymph nodes using diffusion-weighted imaging (DWI). MaterialsWe conducted a retrospective cohort study of patients who underwent pantomography and magnetic resonance imaging (MRI) between November 2017 and July 2018. The participants comprised 101 patients with 389 nodes (males: 22, females: 79, mean age: 44.33 [range: 14–77] years). The correlation between the age group of the criterion variable and ADC value of the explanatory variable was analyzed using Spearman's correlation coefficient. p < 0.05 was considered statistically significant. ResultsThere was a significant negative correlation between age and the ADC values for each sex (p < 0.001). The mean ADC value of the submandibular nodes for all age groups was 0.88 ± 0.15 × 10−3 mm2/s in men and 0.83 ± 0.12 × 10−3 mm2/s in women (p = 0.211). The mean ADC value of the superior internal jugular nodes for all age groups was 0.90 ± 0.14 × 10−3 mm2/s in men and 0.91 ± 0.16 × 10−3 mm2/s in women (p = 0.857). ConclusionsThis study demonstrated that normal ADC values of cervical lymph nodes exhibited significant negative correlation with increasing age. These findings could be useful for the diagnosis of cervical lymph node diseases, including malignant tumors.

Pituitary Macroadenoma – Evaluation of Mean Metabolic Ratios and Mean and Normalized Apparent Diffusion Coefficient Values Using Magnetic Resonance Spectroscopy and Diffusion-weighted Imaging in a Central Indian Rural Hospital Setup

Background: MRS and disregard MRI spectroscopy offers the capability of using magnetic resonance imaning (MRI) to noninvasively study tissue biochemistry. MRS is noninvasive technique that is used to study metabolic variance in brain tumors. Furthermore, diffusion-weighted imaging depicts the degree of water molecules diffusing across the unit volume of the region of interest as a result of sophisticated and dedicated software packages. Differences in apparent diffusion coefficient (ADC) values are related to changes in cellularity, cell membrane permeability, intracellular and extracellular diffusion, and tissue structure. Diffusion-weighted MRI is a powerful tool in the characterization of brain neoplasms. The present study attempts to derive the mean metabolite ratios as well as mean values of ADC with normalization in the setting of pituitary macroadenoma. Aim: (1) To evaluate mean metabolic ratios in pituitary macroadenomas using magnetic resonance spectroscopy (MRS) in rural hospital setup in Central India, (2) To evaluate mean apparent diffusion coefficient value with normalization in pituitary macroadenoma using magnetic resonance spectroscopy in a rural hospital setup in Central India. Materials and Methods: A cross-sectional hospital-based observational study conducted over 2 years. All cases registered with Acharya Vinoba Bhave Rural Hospital Sawangi, Wardha, diagnosed as pituitary macroadenomas were included in the present study. All patients were examined on GE Brivo MRI machine with 1.5 Tesla magnetic field strength in the Department of Radiodiagnosis. Diagnostic acumen was augmented with radiological features of brain tumors with metabolic ratios derived from metabolic values and ADC values. Results: Out of 142 patients included, pituitary macroadenoma cases were 18 in number. Observed metabolite ratios were derived from metabolic values obtained on MRS for choline (Cho), creatinine (Cr), lipid lactate, myoinositol, and n-acetyl aspartate (NAA). Ratios were calculated for Cho: Cr, Cho: NAA, Cho: myoinositol and Cho: lipid lactate. The range for Cho: Cr, Cho: NAA, Cho: myoinositol, and Cho: lipid lactate was 1.04–4.73, 0.96–4.12, 1.21–3.12, and 0.72–1.812, respectively. The mean values for Cho: Cr, Cho: NAA, Cho: myoinositol, and Cho: lipid lactate were 1.8655, 1.6094, 1.5561, and 1.4567, respectively. The range of ADC values observed was from 0.821 × 10−3 mm2/s to 1.523 × 10−3 mm2/s. Normalized ADC values were calculated on basis of observed ADC values in the numerator and the average ADC value of gray matter in the denominator which is taken as 0.8 and was in the range of 1.02625 × 10−3 mm2/s to 1.90375 × 10−3 mm2/s. The mean ADC value was calculated as 1.22 × 10−3 mm2/s. The mean normalized ADC value was calculated as 1.52 × 10−3 mm2/s. Conclusion: The research gap analysis toward which research question was framed stands filled up by generated new knowledge in terms of “mean metabolic ratios” and “ADC” values with reference to pituitary macroadenomas in the present study.

Mean and Normalized Apparent Diffusion Coefficient Values and Mean Metabolic Ratios in Cerebral Metastases in Central Indian Rural Hospital Setup

Background: To evaluate mean metabolite ratios and Apparent diffusion co-efficient value with normalization in cerebral metastases using MRS in rural hospital setup in Central India. Method: A cross sectional hospital based observational study conducted over a time period of 2 years. All the cases registered with Acharya Vinoba Bhave Rural Hospital, Sawangi, Wardha, diagnosed on histopathological findings as cerebral metastases were included in this present study. All patients were examined on GE Brivo MRI machine with 1.5 Tesla magnetic field strength in the Department of Radiodiagnosis using b value of 1000 s/sq. mm, slice thickness 5mm, interslice gap 2mm applied in the x, y and z axes, central as well as peripheral portions of the tumor were manually sampled, preferably getting rid of cystic or necrotic areas. Histopathological diagnostic acumen was augmented with ADC values with normalization. Result: Range of ADC values observed was from 0.683 10-3 mm2/s to 0.873 10-3 mm2/s. Normalized ADC values were calculated on basis of observed ADC values and were in range of 0.8537510-3 mm2/s to 1.09125 10-3 mm2/s. Mean ADC value was calculated as 0.749 x 10-3 mm2/s. Mean normalised ADC value was calculated to be 0.9372 x 10-3 mm2/s. Observed metabolite ratios were derived from metabolic values obtained on MRS for Choline, Creatinine, Lipid lactate, myoinositol and n-acetyl aspartate. Range for Choline:Creatinine, Choline:n-acetyl aspartate, choline : myoinositol and choline : lipid lactate was 3.97 to 5.73, 3.24 to 5.76, 4.35 to 5.49 and 0.32 to 0.997 respectively. Mean values for Choline:Creatinine, Choline:n-acetyl aspartate, choline : myoinositol and choline : lipid lactate were 4.1289, 3.7838, 4.1256 and 0.9095 respectively. Conclusion: Research gap analysis towards which research question was framed stands filled up by the generated new knowledge in terms of 'Mean metabolite ratios','Apparent Diffusion Coefficient' and 'Normalised Apparent Diffusion Coefficient' values for cerebral metastases in the present study.

High-risk breast lesions: role of multi-parametric DCE-MRI in detection and histopathological upgrade prediction

BackgroundHigh-risk breast lesions represent 3–21% of all breast lesions and are non-obligate precursors of malignancy. Various studies have evaluated the value of DCE-MRI including DWI and ADC mapping in the detection of high-risk breast lesions, differentiating them from malignant lesions and predicting upgrade risk after surgical excision reducing misdiagnosis and overtreatment. This study is a retrospective review of all image-guided breast biopsy procedures performed in 2021 at our institution, identified 68 patients with histopathologically proven high-risk breast and available MRI examinations with no concurrent ipsilateral malignancy. Image analysis of MRI examinations included morphological criteria, enhancement pattern, dynamic curves, DWI and ADC mapping assessment. Since our knowledge of high-risk breast lesions is still growing, this study is important to evaluate the merits of DCE-MRI in the assessment of high-risk breast lesions, to allow optimization of treatment, better limit it to those women at risk, and avoid overtreatment in women at low risk.ResultsThe mean ADC value of high-risk breast lesions was not significantly different from that of malignant breast lesions (p value = 0.015). Non-mass enhancement and type III enhancing curve proved to be significant indicators of high-risk breast lesions upgrade in surgical pathology. Cut-off average ADC value for differentiating upgraded high-risk lesions from non-upgraded high-risk lesions proved 1.24 mm2/sec with sensitivity and specificity of 94 & 100%, respectively.DiscussionManagement of high-risk breast lesions is important in the screening setting, as they are non-obligate precursors of malignancy, and also function as risk indicators. Frequency and upgrade rates of high-risk lesions detected by MRI provide a reference for clinical management. DCE-MRI has a high negative predictive value in predicting the upgrade risk of high-risk lesions. In this study, non-mass enhancement and type III curve were proven to be indicators of high-risk lesion upgrade. Limitations of the study included small number of patients and limited follow-up period.ConclusionsThe use of multi-parametric DCE-MRI including DWI and ADC mapping provides complementary information to detect high-risk breast lesions and predict their upgrade rate.

Quantitative analysis of masticatory muscle changes by Eichner index using diffusion-weighted imaging.

Diffusion-weighted imaging (DWI) provides quantitative functional information about the microscopic movement of water at the cellular level. However, few reports have quantitatively evaluated histological changes in masticatory muscles due to changes in occlusal relationships using DWI. This study aimed to assess the changes in masticatory muscles by Eichner index using DWI. We analyzed magnetic resonance imaging (MRI) studies of 201 patients from November 2017 to April 2018. Each Eichner index group, age, and sex were used as criterion variables, and the average apparent diffusion coefficient (ADC) values of the masticatory muscles were the explanatory variable. The mean ADC value differences were analyzed in each Eichner index group. We analyzed the data using the Kruskal-Wallis test and post hoc Mann-Whitney test with Bonferroni adjustment multiple regression analysis with Shapiro-Wilk test and Spearman's correlation coefficients. P < 0.05 was considered statistically significant. The mean ADC values of each Eichner classification group were significantly different, with the lowest value in group C (P < 0.001). There was a negative correlation between the ADC value of the masseter, lateral pterygoid muscle, and age (P < 0.001). There were significant differences between the sex groups (P < 0.001). ADC values of masticatory muscles were significantly different in the Eichner index groups. The ADC values of masticatory muscles may be useful for the quantitative evaluation of the masticatory muscles affected by the occlusal state.

Perfusion and diffusion-weighted imaging parameters: Comparison between pre- and postbiopsy MRI for high-grade glioma.

We aimed to evaluate the differences in dynamic susceptibility contrast (DSC)- magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) parameters between the pre- and postbiopsy MRI obtained before treatment in patients with diffuse midline glioma, H3K27-altered. The data of 25 patients with pathologically proven diffuse midline glioma, H3K27-altered, were extracted from our hospital’s database between January 2017 and August 2021. Twenty (median age, 13 years; range, 3–52 years; 12 women) and 8 (13.5 years; 5–68 years; 1 woman) patients underwent preoperative DSC-MRI and DWI before and after biopsy, respectively. The normalized corrected relative cerebral blood volume (ncrCBV), normalized relative cerebral blood flow (nrCBF), and normalized maximum, mean, and minimum apparent diffusion coefficient (ADC) were calculated using the volumes-of-interest of the tumor and normal-appearing reference region. The macroscopic postbiopsy changes (i.e., biopsy tract, tissue defect, and hemorrhage) were meticulously excluded from the postbiopsy measurements. The DSC-MRI and DWI parameters of the pre- and postbiopsy groups were compared using the Mann–Whitney U test. The ncrCBV was significantly lower in the postbiopsy group than in the prebiopsy group [prebiopsy group: median 1.293 (range, 0.513 to 2.547) versus postbiopsy group: 0.877 (0.748 to 1.205), P = .016]. No significant difference was observed in the nrCBF and normalized ADC values, although the median nrCBF was lower in the postbiopsy group. The DSC-MRI parameters differed between the pre- and postbiopsy MRI obtained pretreatment, although the macroscopic postbiopsy changes were carefully excluded from the analysis. The results emphasize the potential danger of integrating and analyzing DSC-MRI parameters derived from pre- and postbiopsy MRI.

Role of diffusion-weighted imaging in differentiating angiomatous meningioma from atypical meningioma

BackgroundConventional magnetic resonance imaging (MRI) characteristics of angiomatous meningioma (AM) and atypical meningioma (ATM) sometimes overlap. However, there are significant differences in the treatment and prognosis of the two tumors. The aim of the study was to assess the role of diffusion-weighted imaging (DWI) in differentiating AM from ATM. MethodsClinical, MRI, and pathological data of 25 patients with AM and 30 patients with ATM were retrospectively analyzed. Main clinical indexes, conventional MRI characteristics, and apparent diffusion coefficient (ADC) values were compared between the two groups, and receiver operating characteristic (ROC) curves were drawn to determine the diagnostic performance of ADC values in distinguishing AM from ATM. ResultsThe minimum ADC value (ADCmin), average ADC value (ADCmean), and relative ADC value (rADC) for AM (908.00 ± 117.00 × 10−6 mm2/s, 921.04 ± 67.09 × 10−6 mm2/s, and 1.15 ± 0.09, respectively) were significantly higher than those for ATM (710.50 ± 79.80 × 10−6 mm2/s, 748.50 ± 67.27 × 10−6 mm2/s, and 0.96 ± 0.09, respectively; all P < 0.05). ROC analysis showed that ADCmin had the best diagnostic performance in distinguishing AM from ATM, with an area under the curve value of 0.977. When using 759.00 × 10−6 mm2/s as the optimal threshold, the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were 90.00 %, 96.00 %, 92.72 %, 96.40 %, and 88.90 %, respectively. ConclusionsDWI plays an important role in differentiating AM from ATM, and ADCmin is the most promising potential parameter that can improve the preoperative diagnostic accuracy of both tumors.

The role of apparent diffusion coefficient histogram metrics for differentiating pediatric medulloblastoma histological variants and molecular groups

Medulloblastoma, a high-grade embryonal tumor, is the most common primary brain malignancy in the pediatric population. Molecular medulloblastoma groups have documented clinically and biologically relevant characteristics. Several authors have attempted to differentiate medulloblastoma molecular groups and histology variants using diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) maps. However, literature on the use of ADC histogram analysis in medulloblastomas is still scarce. This study presents data from a sizable group of pediatric patients with medulloblastoma from a single institution to determine the performance of ADC histogram metrics for differentiating medulloblastoma variants and groups based on both histological and molecular features. In this retrospective study, we evaluated the distribution of absolute and normalized ADC values of medulloblastomas. Tumors were manually segmented and diffusivity metrics calculated on a pixel-by-pixel basis. We calculated a variety of first-order histogram metrics from the ADC maps, including entropy, minimum, 10th percentile, 90th percentile, maximum, mean, median, skewness and kurtosis, to differentiate molecular and histological variants. ADC values of the tumors were also normalized to the bilateral cerebellar cortex and thalami. We used the Kruskal-Wallis and Mann-Whitney U tests to evaluate differences between the groups. We carried out receiver operating characteristic (ROC) curve analysis to evaluate the areas under the curves and to determine the cut-off values for differentiating tumor groups. We found 65 children with confirmed histopathological diagnosis of medulloblastoma. Mean age was 8.3 ± 5.8 years, and 60% (n = 39) were male. One child was excluded because histopathological variant could not be determined. In terms of medulloblastoma variants, tumors were classified as classic (n = 47), desmoplastic/nodular (n = 9), large/cell anaplastic (n = 6) or as having extensive nodularity (n = 2). Seven other children were excluded from the study because of incomplete imaging or equivocal molecular diagnosis. Regarding medulloblastoma molecular groups, there were: wingless (WNT) group (n = 7), sonic hedgehog (SHH) group (n = 14) and non-WNT/non-SHH (n = 36). Our results showed significant differences among the molecular groups in terms of the median (P = 0.002), mean (P = 0.003) and 90th percentile (P = 0.002) ADC histogram metrics. No significant differences among the various medulloblastoma histological variants were found. ADC histogram analysis can be implemented as a complementary tool inthe preoperative evaluation of medulloblastoma in children. This technique can provide valuable information for differentiating among medulloblastoma molecular groups. ADC histogram metrics can help predict medulloblastoma molecular classification preoperatively.

Hemodynamic changes and neuronal damage detected by 9.4 T MRI in rats with chronic cerebral ischemia and cognitive impairment

IntroductionThe bilateral common carotid artery occlusion (BCCAO) rat model is an ideal animal model for simulating the pathology of chronic brain hypoperfusion in humans. However, dynamic changes in neuronal activity, cellular edema, and neuronal structural integrity in vivo after BCCAO have rarely been reported. The purpose of this study is to use a 9.4 T MRI to explore the pathophysiological mechanisms of vascular dementia.Materials and MethodsTwelve Sprague–Dawley (SD) rats were randomly divided into two groups: the sham group and the model group (n = 6 for each group). Rats were subjected to MRI using T2*WI, diffusion tensor imaging (DTI), and DWI sequences by MRI at the following six time points: presurgery and 6 h, 3 days, 7 days, 21 days, and 28 days postsurgery. Then, the T2*, fractional anisotropy (FA), and average apparent diffusion coefficient (ADC) values were measured in the bilateral cortices and hippocampi. After MRI scanning, all rats in both groups were subjected to the Y‐maze test, novel object recognition test, and open‐field test to assess their learning, memory, cognition, and locomotor activity.ResultsThe T2*, FA, and ADC values in the cerebral cortex and hippocampus decreased sharply at 6 h after BCCAO in the model group compared with those of the sham group. By Day 28, the T2* and ADC values gradually increased to close to those in the sham group, but the FA values changed little, and the rats in the model group had worse learning, memory, and cognition and less locomotor activity than the rats in the sham group.ConclusionsThe BCCAO is an ideal rat model for studying the pathophysiological mechanisms of vascular dementia.