Diffusion-weighted Magnetic Resonance Imaging Research Articles

Delta-radiomics features of ADC maps as early predictors of treatment response in lung cancer

ObjectiveInvestigate the feasibility of detecting early treatment-induced tumor tissue changes in patients with advanced lung adenocarcinoma using diffusion-weighted MRI-derived radiomics features.MethodsThis prospective observational study included 144 patients receiving either tyrosine kinase inhibitors (TKI, n = 64) or platinum-based chemotherapy (PBC, n = 80) for the treatment of pulmonary adenocarcinoma. Patients underwent diffusion-weighted MRI the day prior to therapy (baseline, all patients), as well as either + 1 (PBC) or + 7 and + 14 (TKI) days after treatment initiation. One hundred ninety-seven radiomics features were extracted from manually delineated tumor volumes. Feature changes over time were analyzed for correlation with treatment response (TR) according to CT-derived RECIST after 2 months and progression-free survival (PFS).ResultsOut of 14 selected delta-radiomics features, 6 showed significant correlations with PFS or TR. Most significant correlations were found after 14 days. Features quantifying ROI heterogeneity, such as short-run emphasis (p = 0.04(pfs)/0.005(tr)), gradient short-run emphasis (p = 0.06(pfs)/0.01(tr)), and zone percentage (p = 0.02(pfs)/0.01(tr)) increased in patients with overall better TR whereas patients with worse overall response showed an increase in features quantifying ROI homogeneity, such as normalized inverse difference (p = 0.01(pfs)/0.04(tr)). Clustering of these features allows stratification of patients into groups of longer and shorter survival.ConclusionTwo weeks after initiation of treatment, diffusion MRI of lung adenocarcinoma reveals quantifiable tissue-level insights that correlate well with future treatment (non-)response. Diffusion MRI-derived radiomics thus shows promise as an early, radiation-free decision-support to predict efficacy and potentially alter the treatment course early.Critical relevance statementDelta-Radiomics texture features derived from diffusion-weighted MRI of lung adenocarcinoma, acquired as early as 2 weeks after initiation of treatment, are significantly correlated with RECIST TR and PFS as obtained through later morphological imaging.Key PointsMorphological imaging takes time to detect TR in lung cancer, diffusion-weighted MRI might identify response earlier.Several radiomics features are significantly correlated with TR and PFS.Radiomics of diffusion-weighted MRI may facilitate patient stratification and management.Graphical

Activation patterns of rotator-cuff muscles from quantitative IVIM DWI after physical testing

BackgroundThe diagnostic value of clinical rotator cuff (RC) tests is controversial, with only sparse evidence available about their anatomical specificity. We prospectively assessed regional RC muscle activation patterns by means of intravoxel incoherent motion (IVIM) diffusion-weighted magnetic resonance imaging (MRI) after the execution of common clinical RC tests.MethodsTen healthy subjects (five males, five females) underwent three sessions of diffusion-weighted 3-T shoulder MRI before and after testing the supraspinatus (SSP, Jobe test, session 1), subscapularis (SSC, lift-off test, session 2, at least 1 week later), and infraspinatus muscle (ISP, external rotation test, session 3, another week later). IVIM parameters (perfusion fraction, f; pseudo-diffusion coefficient. D*; and their product, fD*) were measured in regions of interest placed in images of the SSP, SSC, ISP, and deltoid muscle. The Wilcoxon signed-rank test was used for group comparisons; p-values were adjusted using the Bonferroni correction.ResultsAfter all tests, fD* was significantly increased in the respective target muscles (SSP, SSC, or ISP; p ≤ 0.001). After SSP testing, an additional significant increase of fD* was observed in the deltoid, the SSC, and the ISP muscle (p < 0.001). After the SSC and ISP tests, no significant concomitant increase of any parameter was observed in the other RC muscles.ConclusionIVIM revealed varying activation patterns of RC muscles for different clinical RC tests. For SSP testing, coactivation of the deltoid and other RC muscles was observed, implying limited anatomical specificity, while the tests for the SSC and ISP specifically activated their respective target muscle.Relevance statementFollowing clinical RC tests, IVIM MRI revealed that SSP testing led to shoulder muscle coactivation, while the SSC and ISP tests specifically activated the target muscles.Key PointsIn this study, intravoxel incoherent motion MRI depicted muscle activation following clinical rotator cuff tests.After supraspinatus testing, coactivation of surrounding shoulder girdle muscles was observed.Subscapularis and infraspinatus tests exhibited isolated activation of their respective target muscles.Graphical

Inter-visit and inter-reader reproducibility of multi-parametric diffusion-weighted MR imaging in longitudinally imaged patients with metabolic dysfunction-associated fatty liver disease and healthy volunteers.

BackgroundDespite the widespread use of diffusion-weighted imaging (DWI) in metabolic dysfunction-associated fatty liver disease (MAFLD), MRI acquisition and quantification techniques vary in the literature suggesting the need for established and reproducible protocols. The goal of this study was to assess inter-visit and inter-reader reproducibility of DWI- and IVIM-derived parameters in patients with MAFLD and healthy volunteers using extensive sampling of the “fast” compartment, non-rigid registration, and exclusion voxels with poor fit quality. MethodsFrom June 2019 to April 2023, 31 subjects (20 patients with biopsy-proven MAFLD and 11 healthy volunteers) were included in this IRB-approved study. Subjects underwent MRI examinations twice within 40 days. 3.0 T DWI was acquired using a respiratory-triggered spin-echo diffusion-weighted echo-planar imaging sequence (b-values of 0, 10, 20, 30, 40, 50, 100, 200, 400, 800 s/mm2). DWI series were co-registered prior to voxel-wise non-linear regression of the IVIM model and voxels with poor fit quality were excluded (normalized root mean squared error ≥ 0.05). IVIM parameters (perfusion fraction, f; diffusion coefficient, D; and pseudo-diffusion coefficient, D*), and apparent diffusion coefficients (ADC) were computed from manual segmentation of the right liver lobe performed by two analysts on two MRI examinations. ResultsAll results are reported for f, D, D*, and ADC respectively. For inter-reader agreement on the first visit, ICC were of 0.985, 0.994, 0.986, and 0.993 respectively. For intra-reader agreement of analyst 1 assessed on both imaging examinations, ICC between visits were of 0.805, 0.759, 0.511, and 0.850 respectively. For inter-reader agreement on the first visit, mean bias and 95 % limits of agreement were (0.00 ± 0.03), (−0.01 ± 0.03) × 10−3 mm2/s, (0.70 ± 10.40) × 10−3 mm2/s, and (−0.02 ± 0.04) × 10−3 mm2/s respectively. For intra-reader agreement of analyst 1, mean bias and 95 % limits of agreement were (0.01 ± 0.09) × 10−3 mm2/s, (−0.01 ± 0.21) × 10−3 mm2/s, (−13.37 ± 56.19) × 10−3 mm2/s, and (−0.01 ± 0.16) × 10−3 mm2/s respectively. Except for parameter D* that was associated with between-subjects parameter variability (P = 0.009), there was no significant variability between subjects, examinations, or readers. ConclusionWith our approach, IVIM parameters f, D, D*, and ADC provided excellent inter-reader agreement and good to very good inter-visit or intra-reader agreement, thus showing the reproducibility of IVIM-DWI of the liver in MAFLD patients and volunteers.

Contrasting association pattern of plasma low-density lipoprotein with white matter integrity in APOE4 carriers versus non-carriers

Apolipoprotein E ε4 (APOE4) is a strong genetic risk factor of Alzheimer’s disease and metabolic dysfunction. However, whether APOE4 and markers of metabolic dysfunction synergistically impact the deterioration of white matter (WM) integrity in older adults remains unknown. In the UK Biobank data, we conducted a multivariate analysis to investigate the interactions between APOE4 and 249 plasma metabolites (measured using nuclear magnetic resonance spectroscopy) with whole-brain WM integrity (measured by diffusion-weighted magnetic resonance imaging) in a cohort of 1917 older adults (aged 65.0–81.0 years; 52.4 % female). Although no main association was observed between either APOE4 or metabolites with WM integrity (adjusted P > 0.05), significant interactions between APOE4 and metabolites with WM integrity were identified. Among the examined metabolites, higher concentrations of low-density lipoprotein and very low-density lipoprotein were associated with a lower level of WM integrity (b=−0.12, CI=−0.14,−0.10) among APOE4 carriers. Conversely, among non-carriers, they were associated with a higher level of WM integrity (b=0.05, CI=0.04,0.07), demonstrating a significant moderation role of APOE4 (b =−0.18, CI=−0.20,−0.15, P<0.00001).

Ischemic core detection threshold of computed tomography perfusion (CTP) in acute stroke.

This study aimed to determine the accuracy of detecting ischemic core volume using computed tomography perfusion (CTP) in patients with suspected acute ischemic stroke compared to diffusion-weighted magnetic resonance imaging (DW-MRI) as the reference standard. This retrospective monocentric study included patients who underwent CTP and DW-MRI for suspected acute ischemic stroke. The ischemic core size was measured at DW-MRI. The detectability threshold volume was defined as the lowest volume detected by each method. Clinical data on revascularization therapy, along with the clinical decision that influenced the choice, were collected. Volumes of the ischemic cores were compared using the Mann-Whitney U test. Of 83 patients who underwent CTP, 52 patients (median age 73years, IQR 63-80, 36 men) also had DW-MRI and were included, with a total of 70 ischemic cores. Regarding ischemic cores, only 18/70 (26%) were detected by both CTP and DW-MRI, while 52/70 (74%) were detected only by DW-MRI. The median volume of the 52 ischemic cores undetected on CTP (0.6mL, IQR 0.2-1.3mL) was significantly lower (p < 0.001) than that of the 18 ischemic cores detected on CTP (14.2mL, IQR 7.0-18.4mL). The smallest ischemic core detected on CTP had a volume of 5.0mL. Among the 20 patients with undetected ischemic core on CTP, only 10% (2/20) received thrombolysis treatment. CTP maps failed in detecting ischemic cores smaller than 5mL. DW-MRI remains essential for suspected small ischemic brain lesions to guide a correct treatment decision-making.

Quantitative and Radiological Assessment of Post-cardiac-Arrest Comatose Patients with Diffusion-Weighted Magnetic Resonance Imaging.

Although magnetic resonance imaging, particularly diffusion-weighted imaging, has increasingly been used as part of a multimodal approach to prognostication in patients who are comatose after cardiac arrest, the performance of quantitative analysis of apparent diffusion coefficient (ADC) maps, as compared to standard radiologist impression, has not been well characterized. This retrospective study evaluated quantitative ADC analysis to the identification of anoxic brain injury by diffusion abnormalities on standard clinical magnetic resonance imaging reports. The cohort included 204 previously described comatose patients after cardiac arrest. Clinical outcome was assessed by (1) 3-6 month post-cardiac-arrest cerebral performance category and (2) coma recovery to following commands. Radiological evaluation was obtained from clinical reports and characterized as diffuse, cortex only, deep gray matter structures only, or no anoxic injury. Quantitative analyses of ADC maps were obtained in specific regions of interest (ROIs), whole cortex, and whole brain. A subgroup analysis of 172 was performed after eliminating images with artifacts and preexisting lesions. Radiological assessment outperformed quantitative assessment over all evaluated regions (area under the curve [AUC] 0.80 for radiological interpretation and 0.70 for the occipital region, the best performing ROI, p = 0.011); agreement was substantial for all regions. Radiological assessment still outperformed quantitative analysis in the subgroup analysis, though by smaller margins and with substantial to near-perfect agreement. When assessing for coma recovery only, the difference was no longer significant (AUC 0.83 vs. 0.81 for the occipital region, p = 0.70). Although quantitative analysis eliminates interrater differences in the interpretation of abnormal diffusion imaging and avoids bias from other prediction modalities, clinical radiologist interpretation has a higher predictive value for outcome. Agreement between radiological and quantitative analysis improved when using high-quality scans and when assessing for coma recovery using following commands. Quantitative assessment may thus be more subject to variability in both clinical management and scan quality than radiological assessment.

Comparative study of ultra-high field diffusion-weighted MRI imaging between hepatocellular carcinoma and paracancerous, distant cancerous, and background liver tissues

Objective: To investigate the differences in multi-b-value apparent diffusion coefficient (ADC) and exponential apparent diffusion coefficient (eADC) between hepatocellular carcinoma (HCC) and paracancerous liver tissue, distant cancerous liver tissue, and background liver tissues by ultra-high field 3.0T diffusion-weighted (DWI) MRI imaging. Methods: Sixty-eight consecutive HCC cases confirmed by surgical pathology from January 2018 to October 2021 were enrolled and divided into a cirrhosis (n=39) and a non-cirrhosis group (n=29) according to the presence or absence of cirrhosis.The average ADC and eADC of liver tissues of paracancerous (including proximal and distal), distant cancerous, and background were measured by DWI images with diffusion sensitivity factors (b) of 50, 100, 400, 600 s/mm2, and 1 000 s/mm2, respectively. The Kruskal-Wallis H test and Bonferroni method were used to test the differences between the measured values of the five tissues. The statistical differences were used to evaluate the diagnostic efficacy of the five tissues by parametric receiver operating characteristic (ROC) curve and area under the curve (AUC). Results: The comparison of average ADC and eADC among five types of tissues in the liver cirrhosis group showed that the average ADC and eADC measured at b values of 50, 100, 400, and 600 s/mm2 had statistically significant differences (adjusted P<0.005) between cancerous and proximal paracancerous, distal paracancerous, distant cancerous, and background liver tissue, as well as the average ADC measured at b=1 000 s/mm2 between cancerous and proximal paracancerous tissue. The average ADC and eADC in the non-cirrhosis group had statistically significant differences (adjusted P<0.005) between cancerous and proximal paracancerous, distant paracancerous, distant cancerous, and background liver tissue measured at b values of 50, 100, and 400 s/mm2, respectively. The average ADC and eADC measured at b=600 s/mm2 showed statistically significant differences (adjusted P<0.005) between cancerous and proximal paracancerous, distal paracancerous, and distant cancerous liver tissue, as well as the average ADC measured at b=1 000 s/mm2 between cancerous and distal paracancerous, and distant cancerous liver tissue. The average ADC and eADC in the cirrhosis group had no statistically significant difference between the proximal paracancerous and the distant cancerous, as well as the background liver tissue measured at b-values of 50, 100, 400, 600, and 1 000 s/mm2, respectively (adjusted P>0.005), while there were statistically significant differences (adjusted P<0.005) in the average ADC values in the non-cirrhosis group between the proximal paracancerous and the distant paracancerous and background liver tissues at b=50 s/mm2, as well as the average ADC and eADC values between the proximal paracancerous and the distant liver tissues at b=100 s/mm2. The average ADC and eADC values measured in the cirrhosis group and non-cirrhosis group had no statistically significant difference between the distant paracancerous, distant cancerous, and background liver tissue (adjusted P>0.005). The efficacy of average ADC and eADC in distinguishing five types of tissues (cancerous and proximal paracancerous, distant paracancerous, distant cancerous, and background liver tissue) showed that in the cirrhosis group, the diagnostic efficacy was best at b=50 s/mm2. The area under the ROC curve (AUC) of average ADC was 0.815, 0.828, 0.855, and 0.855, respectively, and the AUC of average eADC was 0.815, 0.830, 0.856, and 0.855, respectively. The diagnostic efficacy was best in the non cirrhosis group at b=100 s/mm2, with average ADC AUCs of 0.787, 0.823, 0.841, and 0.821, and average eADC AUCs of 0.836, 0.874, 0.893, and 0.873, respectively. The AUC of the average ADC in the non-cirrhosis group for distinguishing between proximal paracancerous and distant cancerous liver tissues, as well as proximal paracancerous and background liver tissues, with b=50 s/mm2, were 0.605 and 0.604, respectively. The average AUC of ADC and eADC for distinguishing between proximal paracancerous and distant liver tissues with b=100 s/mm2 were 0.619 and 0.620, respectively. Conclusion: The average ADC and eADC measured by multiple b-values are helpful in distinguishing HCC from proximal paracancerous, distal paracancerous, distant-cancerous, and background liver tissues in patients with cirrhosis and non-cirrhosis, while the average ADC and eADC at b=50 s/mm2 and 100 s/mm2 exhibit differences between the proximal paracancerous from the distant cancerous liver tissue and background liver tissue in patients with non-cirrhosis.

Application and prospects of magnetic resonance imaging techniques in the diagnosis and evaluation of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common primary malignant tumor of the liver. MRI has become an important imaging method for non-invasive diagnosis and evaluation of HCC in clinics because of its advantageous aspects, such as its non-radiative nature, superior detection, and qualitative accuracy over CT and ultrasound. Various MRI techniques, including hepatobiliary-specific contrast agents, magnetic resonance elastography, diffusion-weighted imaging, and others, can diagnose HCC or evaluate its malignant biological behavior from different dimensions such as blood supply, cell function, tissue hardness, and water molecule diffusion. This article introduces the current status and prospects of various MRI techniques for HCC diagnosis and evaluation.

A case of MERS presenting with acute motor aphasia and tetraparesis and literature review

BackgroundMild encephalopathy wıth reversible splenial lesions (MERS) are a clinical–radiological diagnosis that can be diagnosed with radiological imaging and can be accompanied by impaired consciousness, aphasia, headache, and paralysis. MERS can be divided into two different types based on radiological findings; Involvement of the splenium is seen in type 1, and involvement of the splenium and deep white matter is seen in type 2. MERS Type 2 is very rare in adults. Here, we describe a patient diagnosed with MERS Type 2 and our therapeutic intervention.Case presentationA 22-year-old woman presented with slurred speech, weakness in the extremities and headache that started 14 h ago. The patient had sore throat and fever of 37.6 °C for 2 days, and medical history or family history were unremarkable. Neurological examination revealed that she was conscious, cooperative, with no signs of meningeal irritation. Speech comprehension, naming, and repetition were preserved, motor examination revealed 5/5 left upper extremity strength, 4/5 right upper extremity strength, and 2/5 bilateral lower extremity strength. Diffusion-weighted magnetic resonance imaging (MRI-DWI) revealed bilateral deep white matter and splenium symmetrical diffusion restriction. Blood tests showed high C-reactive protein (CRP) and no leukocytosis. No cells were detected in the cerebrospinal fluid (CSF), protein was 151 mg/dl, glucose was within normal limits. The patient, who developed quadriparesis during follow-up, was started on pulse dose steroids. Neurological examination improved to patient’s baseline at the 12th hour of treatment. In the 72nd hour control MRI-DWI, it was seen that the lesions had regressed. Culture/Polymerase chain reaction (PCR) for bacterial/viral infection agents came back negative. After steroids were given for 5 days, patient was discharged at her baseline.ConclusionsMERS is a rare diagnosis in adults and can be radiologically confused with acute toxic leukoencephalopathy. It can be distinguished clinically by the absence of prior infection, fever, and toxic agent exposure. Although there is no consensus in the literature regarding the treatment, the clinical picture improved rapidly after steroid in our case. Despite being rare, it should be considered in the differential diagnosis of patients with deep white matter lesions in adults.

Diffusion-Weighted MRI for Recurrent/Persistent Head and Neck Squamous-Cell Carcinoma After Radiotherapy: Systematic Review and Meta-Analysis.

To evaluate the accuracy of diffusion-weighted magnetic resonance imaging (DWI-MRI) in diagnosing persistent/recurrent head and neck squamous cell carcinomas (HNSCCs) after primary chemoradiotherapy (CRT). Scopus, PubMed/MEDLINE, and Cochrane Library databases were searched for relevant publications until April 18, 2023. A systematic review and meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses of Diagnostic Test Accuracy statement. The search was conducted independently by 2 investigators. Methodological quality of included studies was assessed using the Quality Assessment of Diagnostic Studies-2 questionnaire. Extracted data were used to calculate the pooled DWI-MRI sensitivity, specificity, diagnostic odds ratio, and positive and negative likelihood ratio. A total of 618 patients from 10 studies were included for calculation of diagnostic accuracy parameters. At the level of the primary tumor, the pooled sensitivity and specificity were, respectively, 0.96 (95% confidence interval [CI]: 0.89-1.00) and 0.81 (95% CI: 0.54-0.98) in the case of qualitative analysis, and, respectively, 0.79 (95% CI: 0.66-0.89) and 0.88 (95% CI: 0.77-0.96) for quantitative analysis. At the level of the neck, the pooled sensitivity and specificity were, respectively, 0.87 (95% CI: 0.75-0.95) and 0.84 (95% CI: 0.74-0.93) when images were analyzed qualitatively, and 0.79 (95% CI: 0.60-0.94) and 0.90 (95% CI: 0.82-0.97) when analyzed quantitatively. DWI-MRI showed high diagnostic accuracy and should be considered if persistent/recurrent HNSCCs is suspected after primary CRT. No significant differences were found between qualitative and quantitative imaging assessment.

Case series multilocular cystic hemangioma of the liver: Three cases and literature review.

Multilocular cystic hemangioma is a rare benign tumor classified as an atypical hemangioma. Currently, there are limited imaging reports available, and the imaging characteristics can be challenging to distinguish from other malignant multilocular cystic liver diseases such as cystadenocarcinoma, necessitating confirmation through pathological diagnosis. Here, we discuss the imaging features of 3 cases of multilocular cystic hemangiomas. Case 1 was a 24-year-old young female, and Case 2 involved a 60-year-old elderly male. Both patients were asymptomatic and physical examination revealed hepatic space-occupying lesions. Imaging findings revealed multilocular cystic lesions in the left liver with septa, calcification, a high diffusion-weighted magnetic resonance imaging (DWI) signal at the edge of the lesion, and progressive enhancement of the cyst wall and septa. Case 3 involved a 50-year-old male patient with epigastric distending pain for 1 month and sudden severe abdominal pain for 14 hours. Imaging results revealed a multilocular cystic lesion in the left liver with septa and tumor bleeding, a high DWI signal, and an enhanced cyst wall and septa. The pathological diagnosis confirmed a hepatic hemangioma. All 3 patients underwent liver tumor resection. All 3 patients recovered successfully without any intraoperative or postoperative complications during the follow-up periods of 5 years, 6 months, and 5 months. There were no signs of recurrence. Liver imaging revealed multilocular cystic lesions with features, such as compartmentalization, calcification, or bleeding. Multilocular cystic hemangiomas should be considered in imaging diagnosis. Enhancing our understanding of multilocular cystic hemangiomas can aid in improving the differential diagnosis of other malignant multilocular cystic liver diseases, ultimately reducing unnecessary liver resection.

Functional and structural maturation of auditory cortex from 2 months to 2 years old

BackgroundIn school-age children, the myelination of the auditory radiation thalamocortical pathway is associated with the latency of auditory evoked responses, with the myelination of thalamocortical axons facilitating the rapid propagation of acoustic information. Little is known regarding this auditory system function-structure association in infants and toddlers. Methods and ParticipantsThe present study tested the hypothesis that maturation of auditory radiation white-matter microstructure (e.g., fractional anisotropy (FA); measured using diffusion-weighted MRI) is associated with the latency of the infant auditory response (the P2m response, measured using magnetoencephalography, MEG) in a cross-sectional (N = 47, 2 to 24 months, 19 females) as well as longitudinal cohort (N = 18, 2 to 29 months, 8 females) of typically developing infants and toddlers. Of 18 longitudinal infants, 2 infants had data from 3 timepoints and 16 infants had data from 2 timepoints. ResultsIn the cross-sectional sample, non-linear maturation of P2m latency and auditory radiation diffusion measures were observed. Auditory radiation diffusion accounted for significant variance in P2m latency, even after removing the variance associated with age in both P2m latency and auditory radiation diffusion measures. In the longitudinal sample, latency and FA associations could be observed at the level of a single child. ConclusionsFindings provide strong support for the hypothesis that an increase in thalamocortical neural conduction velocity, due to increased axon diameter and/or myelin maturation, contributes to a decrease in the infant P2m auditory evoked response latency. SignificanceInfant multimodal brain imaging identifies brain mechanisms contributing to the rapid changes in neural circuit activity during the first two years of life.

Apparent Diffusion Coefficient in the Diagnosis and Follow-up of Multiple Sclerosis: Role of Magnetic Resonance Imaging

Background: Chronic Multiple Sclerosis (MS) modifies the apparent diffusion coefficient (ADC) value due to severe pathological changes. After trauma, it is the second most common cause of brain injury in healthy young adults. MRI is considered the initial imaging modality for MS diagnosis and follow-up. Objective: To assess the significance of the ADC in the diagnosis and follow-up of MS plaques across various disease subtypes. Methods: Forty MS patients were included in a case-control study at Ibn-Sina Teaching Hospital, Mosul Province, between June 1, 2022 and February 28, 2023. The patients had diffusion-weighted and traditional MR imaging with ADC measurement in plaques, and the normal white matter value of controls was compared to the patients' results. Results: The ADC values were higher in cases that were acute or secondary-progressive than in relapsing-remitting cases or normal white matter. In both types of newly generated plaques, there was an initial non-significant increase in ADC values compared to existing plaques. Overall, the ADC sensitivity, specificity, and accuracy in diagnosing MS were 85.7%, 95.2%, and 90.5% in acute cases, and 85.7%, 83.3%, and 84.6% in chronic cases, respectively, with no significant difference between active and inactive lesions. Conclusions: The apparent diffusion coefficient value can be included in the imaging protocol for the diagnosis and follow-up of various subtypes of MS.

Clinical and subclinical microemboli following neuroangiography in children

BackgroundTo assess the frequency, imaging appearances, and risk factors of brain microemboli following pediatric neuroangiography, as assessed by early diffusion-weighted MRI imaging (DWI).MethodsThis single-center, retrospective analysis investigated early DWI post-pediatric...

A novel low-rank reconstruction framework for precise fat-tumor discrimination in diffusion-weighted MRI

A novel low-rank reconstruction framework for precise fat-tumor discrimination in diffusion-weighted MRI

MRI-Derived Modeling of Disease Progression Patterns in Patients With Temporal Lobe Epilepsy.

Temporal lobe epilepsy (TLE) is assumed to follow a steady course that is similar across patients. To date, phenotypic and temporal diversities of TLE evolution remain unknown. In this study, we aimed at simultaneously characterizing these sources of variability based on cross-sectional data. We studied consecutive patients with TLE referred for evaluation by neurologists to the Montreal Neurological Institute epilepsy clinic, who underwent in-patient video EEG monitoring and multimodal imaging at 3 Tesla, comprising 3D T1 and fluid-attenuated inversion recovery and 2D diffusion-weighted MRI. The cohort included patients with drug-resistant epilepsy and patients with drug-responsive epilepsy. The neuropsychological evaluation included Wechsler Adult Intelligence Scale-III and Leonard tapping task. The control group consisted of participants without TLE recruited through advertisement and who underwent the same MRI acquisition as patients. Based on surface-based analysis of key MRI markers of pathology (gray matter morphology and white matter microstructure), the Subtype and Stage Inference algorithm estimated subtypes and stages of brain pathology to which individual patients were assigned. The number of subtypes was determined by running the algorithm 100 times and estimating mean and SD of disease trajectories and the consistency of patients' assignments based on 1,000 bootstrap samples. Effect of normal aging was subtracted from patients. We examined associations with clinical and cognitive parameters and utility for individualized predictions. We studied 82 patients with TLE (52 female, mean age 35 ± 10 years; 11 drug-responsive) and 41 control participants (23 male, mean age 32 ± 8 years). Among 57 operated, 43/37/20 had Engel-I outcome/hippocampal sclerosis/hippocampal isolated gliosis, respectively. We identified 3 trajectory subtypes: S1 (n = 35), led by ipsilateral hippocampal atrophy and gliosis, followed by white-matter damage; S2 (n = 27), characterized by bilateral neocortical atrophy, followed by ipsilateral hippocampal atrophy and gliosis; and S3 (n = 20), typified by bilateral limbic white-matter damage, followed by bilateral hippocampal gliosis. Patients showed high assignability to their subtypes and stages (>90% bootstrap agreement). S1 had the highest proportions of patients with early disease onset (effect size d = 0.27 vs S2, d = 0.73 vs S3), febrile convulsions (χ2 = 3.70), drug resistance (χ2 = 2.94), a positive MRI (χ2 = 8.42), hippocampal sclerosis (χ2 = 7.57), and Engel-I outcome (χ2 = 1.51), pFDR < 0.05 across all comparisons. S2 and S3 exhibited the intermediate and lowest proportions, respectively. Verbal IQ and digit span were lower in S1 (d = 0.65 and d = 0.50, pFDR < 0.05) and S2 (d = 0.76 and d = 1.09, pFDR < 0.05), compared with S3. We observed progressive decline in sequential motor tapping in S1 and S3 (T = -3.38 and T = -4.94, pFDR = 0.027), compared with S2 (T = 2.14, pFDR = 0.035). S3 showed progressive decline in digit span (T = -5.83, p = 0.021). Supervised classifiers trained on subtype and stage outperformed subtype-only and stage-only models predicting drug response in 73% ± 1.0% (vs 70% ± 1.4% and 63% ± 1.3%) and 76% ± 1.6% for Engel-I outcome (vs 71% ± 0.8% and 72% ± 1.1%), pFDR < 0.05 across all comparisons. Cross-sectional MRI-derived models provide reliable prognostic markers of TLE disease evolution, which follows distinct trajectories, each associated with divergent patterns of hippocampal and whole-brain structural alterations, as well as cognitive and clinical profiles.

Alx3 deficiency disrupts energy homeostasis, alters body composition, and impairs hypothalamic regulation of food intake

The coordination of food intake, energy storage, and expenditure involves complex interactions between hypothalamic neurons and peripheral tissues including pancreatic islets, adipocytes, muscle, and liver. Previous research shows that deficiency of the transcription factor Alx3 alters pancreatic islet-dependent glucose homeostasis. In this study we carried out a comprehensive assessment of metabolic alterations in Alx3 deficiency. We report that Alx3-deficient mice exhibit decreased food intake without changes in body weight, along with reduced energy expenditure and altered respiratory exchange ratio. Magnetic resonance imaging reveals increased adiposity and decreased muscle mass, which was associated with markers of motor and sympathetic denervation. By contrast, Alx3-deficient mice on a high-fat diet show attenuated weight gain and improved insulin sensitivity, compared to control mice. Gene expression analysis demonstrates altered lipogenic and lipolytic gene profiles. In wild type mice Alx3 is expressed in hypothalamic arcuate nucleus neurons, but not in major peripheral metabolic organs. Functional diffusion-weighted magnetic resonance imaging reveals selective hypothalamic responses to fasting in the arcuate nucleus of Alx3-deficient mice. Additionally, altered expression of proopiomelanocortin and melanocortin-3 receptor mRNA in the hypothalamus suggests impaired regulation of feeding behavior. This study highlights the crucial role for Alx3 in governing food intake, energy homeostasis, and metabolic nutrient partitioning, thereby influencing body mass composition.

A worldwide study of white matter microstructural alterations in people living with Parkinson’s disease

The progression of Parkinson’s disease (PD) is associated with microstructural alterations in neural pathways, contributing to both motor and cognitive decline. However, conflicting findings have emerged due to the use of heterogeneous methods in small studies. Here we performed a large diffusion MRI study in PD, integrating data from 17 cohorts worldwide, to identify stage-specific profiles of white matter differences. Diffusion-weighted MRI data from 1654 participants diagnosed with PD (age: 20–89 years; 33% female) and 885 controls (age: 19–84 years; 47% female) were analyzed using the ENIGMA-DTI protocol to evaluate white matter microstructure. Skeletonized maps of fractional anisotropy (FA) and mean diffusivity (MD) were compared across Hoehn and Yahr (HY) disease groups and controls to reveal the profile of white matter alterations at different stages. We found an enhanced, more widespread pattern of microstructural alterations with each stage of PD, with eventually lower FA and higher MD in almost all regions of interest: Cohen’s d effect sizes reached d = −1.01 for FA differences in the fornix at PD HY Stage 4/5. The early PD signature in HY stage 1 included higher FA and lower MD across the entire white matter skeleton, in a direction opposite to that typical of other neurodegenerative diseases. FA and MD were associated with motor and non-motor clinical dysfunction. While overridden by degenerative changes in the later stages of PD, early PD is associated with paradoxically higher FA and lower MD in PD, consistent with early compensatory changes associated with the disorder.

Fat-signal suppression in breast diffusion-weighted imaging: the Good, the Bad, and the Ugly.

Fat-signal suppression is essential for breast diffusion magnetic resonance imaging (or diffusion-weighted MRI, DWI) as the very low diffusion coefficient of fat tends to decrease absolute diffusion coefficient (ADC) values. Among several methods, the STIR (short-tau inversion recovery) method is a popular approach, but signal suppression/attenuation is not specific to fat contrary to other methods such as SPAIR (spectral adiabatic (or attenuated) inversion recovery). This article focuses on those two techniques to illustrate the importance of appropriate fat suppression in breast DWI, briefly presenting the pros and cons of both approaches. We show here through simulation and data acquired in a dedicated breast DWI phantom made of vials with water and various concentrations of polyvinylpyrrolidone (PVP) how ADC values obtained with STIR DWI may be biased toward tissue componentswith the longest T1 values: ADC values obtained with STIR fat suppression may be over/underestimated depending on the T1 and ADC profile within tissues. This bias is also illustrated in twoclinical examples. Fat-specific methods should be preferred over STIR for fat-signal suppression in breast DWI, such as SPAIR which also provides a higher sensitivity than STIR for lesion detection. One should remain aware, however, that efficient fat-signal suppression with SPAIR requires good B0 shimming to avoid ADC underestimation from residual fat contamination. The spectral adiabatic (or attenuated) inversion recovery (SPAIR) method should be preferred over short-tau inversion recovery (STIR) for fat suppression in breast DWI. Fat-signal suppression is essential for breast DWI; the SPAIR method is recommended. Short-tau inversion recovery (STIR)is not specific to fat; as a result, SNR is decreased and ADC values may be over- or underestimated. The STIR fat-suppression method must not be used after the injection of gadolinium-based contrast agents.

CLINICAL APPLICATION STUDY OF 3D-ASL PERFUSION IMAGING AND MAGNETIC RESONANCE DIFFUSION IMAGING IN TRANSIENT ISCHEMIC ATTACK.

Objective: This study aimed to explore the clinical application of three-dimensional arterial spin labeling (3D-ASL) and diffusion-weighted magnetic resonance imaging (DWI) in transient ischemic attacks. Methods: Forty patients with transient cerebral ischemia in our hospital were selected and included from July 2020 to March 2022. All subjects were detected by DWI and 3D-ASL technology. The positive rate, relative cerebral blood flow (rCBF), and the receiver operating characteristic curve of the two methods in the diagnosis of transient cerebral ischemia were compared; the objective was to compare the relationship between the frequency of transient ischemic attack and hypoperfusion, and vascular stenosis. Results: The 3D-ASL examination showed two cases of hypoperfusion in the healthy control group (5.00), and the magnetic resonance imaging examination showed four cases of vascular stenosis in the healthy control group (10.00). The rCBF ratio in the cerebral ischemia group was significantly lower than that in the cerebral ischemia group, which was significantly lower than that in the healthy control group ( P < 0.05). The area under the curve (AUC) of 3D-ASL in the diagnosis of transient cerebral ischemia was 0.800, and the AUC of DWI in the diagnosis of transient cerebral ischemia was 0.725. The AUC of the combination of the two methods in transient cerebral ischemia was 0.850. There was a significant difference in the attack frequency of patients with transient cerebral ischemia with different perfusion ( P < 0.05). There was a significant difference in attack frequency between patients with transient ischemic attack and patients without vascular stenosis ( P < 0.05). Conclusion: 3D-ASL and DWI technology have higher diagnostic efficiency for transient cerebral ischemia.