Magnetic Resonance Diffusion Tensor Imaging Research Articles

Abstract TMP52: Corticospinal Tractography and Motor Function in Patients Undergoing Intracerebral Hemorrhage Evacuation

Introduction: A recent randomized-controlled trial confirmed the value of minimally-invasive intracerebral hemorrhage (ICH) evacuation to improve outcomes in properly-selected patients. Yet, there remains a need to optimize patient selection and prognosis following ICH evacuation. Magnetic resonance diffusion tensor imaging (DTI) allows visualization and quantification of critical white matter tracts. Corticospinal tract DTI (CST-DTI) in particular can be associated with motor function, which may improve prognosis and patient selection for ICH evacuation. Methods: Patients who underwent minimally-invasive ICH evacuation and had perioperative DTI performed were retrospectively reviewed. CST metrics including fractional anisotropy, radial diffusivity, axial diffusivity, geodesic anisotropy, fiber count, and tract volume were associated with motor function pre- and postoperatively. Motor function was scored on each hemibody via the weakest muscle group in each extremity according to the Medical Research Council grading scale (maximum score of 10 on each hemibody). Results: Eighteen patients with available peri-operative DTI data were included, 12 each with preoperative and postoperative DTI, seven with matched pre- and postoperative DTI. Preoperative geodesic anisotropy was significantly associated with both preoperative motor function on the contralateral hemibody (R=0.616, p=0.032, Pearson correlation) and at postoperative day one (R=0.606, p=0.038). Restoration of a deformed CST could be seen in several patients from preoperative to the immediate postoperative period ( Figure 1) . However, no preoperative or postoperative CST-DTI metrics were associated with motor scores at a median follow-up of 6.3 months post-ICH (p>0.05 for all comparisons). There was a significant increase in motor scores on the affected hemibody from postoperative day one to last follow-up (3.8±3.5 vs 6.3±6.8; p = 0.038, Wilcox signed-rank test). Conclusions: Preoperative CST-DTI metrics are associated with both preoperative and immediate postoperative motor function after minimally invasive ICH evacuation. A restored CST after ICH evacuation could be seen in a subset of patients. However, neither preoperative nor immediate postoperative CST-DTI metrics were associated with longer-term motor function. Tractography from the perioperative period should be used with caution in providing motor prognosis.

Volumetric magnetic resonance imaging and diffusion tensor imaging metrics correlate with clinical outcomes following gene therapy in GM1 gangliosidosis patients

Volumetric magnetic resonance imaging and diffusion tensor imaging metrics correlate with clinical outcomes following gene therapy in GM1 gangliosidosis patients

Phenotype differentiation and white matter preservation by early hematopoietic cell transplantation – Free-water diffusion tensor MRI study of the brain in mucopolysaccharidosis type I patients

Phenotype differentiation and white matter preservation by early hematopoietic cell transplantation – Free-water diffusion tensor MRI study of the brain in mucopolysaccharidosis type I patients

Intradermal Advanced Glycation End-products Relate to Reduced Sciatic Nerve Structural Integrity in Type2 Diabetes.

Cardiovascular risk management is beneficial, but stringent glycemic control does not prevent the progression of distal sensorimotor polyneuropathy (DSPN). Persistent hyperglycemia-induced alterations and cardiovascular factors may contribute to diabetes-associated nerve damage. This study aimed to evaluate the correlation between skin auto-fluorescence (sAF), an indicator of dermal advanced glycation end-product (AGE) accumulations, cardiovascular risk, and changes in peripheral nerve integrity. Sixty-two individuals with type2 diabetes (T2D) (20women and 42men), including 29 diagnosed with DSPN (7women and 22men), and 10healthy controls (HC) underwent diffusion tensor MR imaging of the sciatic nerve to assess fractional anisotropy (FA), an indicator of nerve structural integrity. sAF measurements were combined with clinical, serological, and electrophysiological evaluations. Arterial stiffness was assessed via pulse wave velocity (PWV). sAF (HC 2.1 ± 0.25 AU, nDSPN 2.3 ± 0.47, DSPN 2.6 ± 0.43; p = 0.005) was higher in individuals with DSPN compared to HC (p = 0.010) and individuals without DSPN (p = 0.035). Within the group of T2D FA correlated negatively with sAF (r = -0.49, p < 0.001), PWV (r = -0.40, p = 0.009) and high-sensitivity troponinT (hsTNT), amarker of microvascular damage (r = -0.39, p < 0.001). In DSPN, sAF correlated positively with hsTNT (r = 0.58, p = 0.005) and with PWV (r = 0.52, p = 0.007), the sciatic nerve's FA correlated negatively with PWV (r = -0.47, p = 0.010). This study is the first to show close correlations between reduced peripheral nerve integrity and both intradermal AGE deposition and arterial stiffness in individuals with T2D. These findings highlight amechanistic link between glycation-related vascular injury and neuronal damage emphasizing the importance of cardiovascular risk management in preventing DSPN.

Abnormal alterations in structure-function coupling at the modular level in patients with postherpetic neuralgia

To investigate the presence of modular loss of coupling and abnormal alterations in functional and structural networks in the brain networks of patients with postherpetic neuralgia (PHN). We collected resting-state functional magnetic resonance imaging data and diffusion tensor imaging data from 82 healthy controls (HCs) and 71 PHN patients, generated structural connectivity (SC) and functional connectivity (FC) networks, and assessed the corresponding clinical information assessment. Based on AAL(90) mapping, the brain network was divided into 9 modules, and the structural–functional connectivity (SC–FC) coupling was compared at the whole-brain level and within the modules, as well as alterations in the topological properties of the brain network in the patient group. Finally, correlation analyses were performed using the following clinical scales: Visual Analogue Scale (VAS), Hamilton Anxiety Scale (HAMA), and Hamilton Depression Scale (HAMD). Compared with HCs, patients with PHN had reduced global efficiency (Eg) and local efficiency (Eloc) of structural and functional networks. The FC in the PHN group presented abnormal node clustering coefficients (NCp), local node efficiencies (NLe), and node efficiencies (Ne), and the SC presented abnormal node degrees (Dc), NCp, NLe, characteristic path lengths (NLp), and Ne. In addition, SC–FC coupling was reduced in the patient default network (DMN), salient network (SN), and visual network (VIS). Moreover, the degree of impairment of graph theory indicators was significantly positively correlated with scales such as VAS scores, and the coupling of modules was significantly negatively correlated with the early course of the patient’s disease. Large-scale impaired topological properties of the FC and SC networks were observed in patients with PHN, and SC–FC decoupling was detected in these modules of the DMN, SN, and VIS. These aberrant alterations may have led to over-transmission of pain information or central sensitization of pain.

Alterations in whole muscle quality and physiological cross-sectional area measured with quantitative MRI following ACL injury

BackgroundEmerging evidence suggests that there are morphological and physiological changes to the vastus lateralis after an anterior cruciate ligament (ACL) tear. However, it is unclear whether these alterations are limited to just the vastus lateralis or are more representative of widespread changes across the thigh musculature and/or if these changes precede reconstruction. The purpose of this study was to determine T1ρ relaxation time, a measure of extracellular matrix organization in muscle, and physiological cross-sectional area (PCSA) for muscles of the quadriceps and hamstrings of the ACL-deficient and contralateral limbs soon after ACL injury.MethodsT1ρ and diffusion tensor magnetic resonance imaging were performed on both limbs of 10 participants after primary ACL tear (< 10 weeks). T1ρ relaxation time and PCSA were calculated for all muscles of the quadriceps and hamstrings. Shapiro-Wilks tests were performed to assess normality. Outcomes were compared between limbs for each muscle of interest with paired t-tests or Wilcoxon signed-rank tests with the alpha level set to 0.05.ResultsT1ρ relaxation times were significantly longer for the vastus lateralis (7.0%), rectus femoris (15.4%), and vastus intermedius (9.4%) of ACL-deficient limb; whereas, relaxation times were similar between limbs for all hamstring muscles. PCSA was smaller for the vastus lateralis (-19.6%), vastus intermedius (-20.9%), vastus medialis (-26.0%), and semitendinosus (-15.0%) of the ACL-deficient limb compared to the contralateral limb.ConclusionsThese results provide evidence that morphological and physiological alterations occur within multiple muscles of quadriceps but not the hamstrings prior to ACL reconstruction. Establishing these differences between the quadriceps and hamstrings suggests there is a differential response within the thigh musculature to an ACL injury, providing a framework for more targeted interventions.

Effect of physical exercise on white matter microstructure in chemotherapy-treated breast cancer patients: a randomized controlled trial (PAM study).

Physical exercise is a promising intervention to improve brain white matter integrity. In the PAM study, exercise intervention effects on white matter integrity were investigated in breast cancer patients. Chemotherapy-treated breast cancer patients with cognitive problems were randomized 2-4years post-diagnosis to an exercise (n = 91) or control group (n = 90). The 6-month exercise intervention consisted of four hours/week of aerobic and resistance training. White matter integrity was measured at baseline and 6-month follow-up with fractional anisotropy (FA) and mean diffusivity (MD), which were derived from magnetic resonance diffusion tensor imaging (DTI). Both DTI metrics were analyzed whole brain and voxel-wise with a modified tract based spatial statistics (TBSS) procedure. Other measurements included cognition and physical fitness. Exercise effects were analyzed with multiple regression analyses. An explorative analysis was conducted in highly fatigued patients. DTI scans were available for 69 patients of the intervention (age = 52.3 ± 8.9yrs.) and 72 patients of the control group (age = 53.2 ± 8.6yrs.). Whole brain and voxel-wise analyses revealed no significant intervention effects on FA and MD. In highly fatigued patients (exercise: n = 32; control: n = 24), significant clusters of decreased FA post-intervention were observed in the left inferior and superior longitudinal fasciculus. Mean FA in these clusters was not predictive of cognition. A 6-month exercise intervention did not affect white matter integrity in chemotherapy-treated breast cancer patients. However, in highly fatigued breast cancer patients a significant FA decrease was observed post-intervention. The direction of these results is unexpected, and more research is needed to further understand these results.

Feasibility study for evaluating cervical intervertebral disc degeneration using axial diffusion tensor imaging.

Intervertebral disc (IVD) degeneration is the main cause of neck pain. Although conventional magnetic resonance imaging can detect morphological changes in intervertebral disc degeneration, it cannot provide accurate and objective evaluations. Magnetic resonance diffusion tensor imaging (DTI) reflects the microstructural changes in tissues by describing the diffusion of water molecules. It was initially applied to the evaluation of lumbar disc degeneration; however, no study has used DTI to evaluate cervical disc degeneration. To conduct a prospective study to evaluate the efficacy and feasibility of DTI in quantifying cervical disc degeneration by correlating the main parameters of axial DTI of intervertebral discs, namely fractional anisotropy (FA) and mean diffusivity (MD) values, using the Pfirrmann grade. The cervical discs of 30 symptomatic volunteers with neck pain and 20 asymptomatic volunteers were assessed using a 3.0 T magnetic resonance scanner. We evaluated intervertebral discs from C3/4 to C6/7 in each volunteer. The Pfirrmann grades, FA value, and MD value on the conventional magnetic resonance imaging were evaluated. The Kruskal-Wallis test and Wilcoxon rank-sum test were used to compare the FA and MD values of subjects with different degeneration levels. Statistical analysis showed that the FA value of the nucleus pulposus in patients group was significantly higher than that in the asymptomatic volunteers, and the MD value of the nucleus pulposus was significantly lower than that in the asymptomatic volunteers, and the difference was significant (P < 0.05). In the study group, with an increase in cervical intervertebral disc grade, the FA value of the nucleus pulposus also showed a gradual upward trend, and this difference was significant (P < 0.05). The MD value of the nucleus pulposus showed a gradual downward trend, except between grades I and II, which indicates that the axial FA value can better show the early pathological changes of the cervical intervertebral disc. The FA and MD values of the cervical intervertebral disc can quantitatively evaluate the degree of degeneration of the cervical intervertebral disc; axial DTI imaging technology can provide a good theoretical basis for the imaging diagnosis of cervical intervertebral disc degeneration and has important clinical application value.

Shared and distinctive changes of the white matter integrity in generalized anxiety disorder with or without depressive disorder.

Generalized anxiety disorder (GAD) is a prevalent anxiety disorder often comorbid with major depressive disorder (MDD). Previous neuroimaging studies have shown that white matter (WM) microstructural alterations are critical for efficient communication between brain regions, and play an important role in the pathology of GAD. However, the exact profile of WM abnormalities in GAD with and without comorbid MDD remain unclear. This study aimed to uncover them using a novel global probabilistic tractography technology named Tracts Constrained by Underlying Anatomy (TRACULA), and to assess the correlations between fascicle integrity and symptom severity. We recruited 20 pure GAD (p-GAD) patients, 14 GAD comorbid with MDD (GAD+MDD) patients, and 41 age- and sex-matched healthy controls (HCs). All participants underwent T1 magnetic resonance imaging and diffusion tensor imaging. For each subject, 42 WM fiber bundles of the whole brain were successfully tracked and calculated with five metrics including volume, fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD) and axial diffusivity (AD). Group comparison were firstly performed between the whole GAD patients and HCs. Then, we compared the differences among the three groups (the p-GAD, GAD+MDD patients and HCs) using the one-way ANCOVA and post hoc analysis with the Bonferroni correction. Furthermore, correlations between abnormal WM metrics and clinical symptom severity were examined using partial correlations analyses among patients. Compare to HCs, both p-GAD and GAD+MDD patients exhibited decreased FA values in left superior longitudinal fasciculus (SLF) II, and right dorsal of cingulum bundle (CBD); Moreover, GAD+MDD patients showed decreased FA, increased MD and RD values in the central and temporal section of the body of the corpus callosum (CC-BODY), right SLF I and II compared to HCs. Within the GAD+MDD group, GAD-7 scores were negatively correlated with FA values (r=-0.75, p=0.008) and positively correlated with RD values (r=0.7, p=0.017) in the right CBD. This study identified both shared and distinctive changes in GAD patients with and without MDD. The shared WM disruption in the p-GAD and GAD+MDD groups located in the left SLF and right CBD, while only GAD+MDD patients showed distinctive changes in the central and temporal sections of the CC-BODY and right SLF. Current study gave a comprehensive characterization of WM abnormalities among these patients, and highlighted TRACULA's value in identifying critical WM changes.

Magnetic Resonance Imaging Techniques for Investigating the MCT8-Deficient Brain in Murine Disease Models.

Magnetic resonance imaging (MRI) techniques have emerged as powerful tools for unraveling the pathophysiology of rare diseases, mainly due to their pivotal role in early diagnosis, disease characterization, and treatment monitoring in a non-invasive manner. In this chapter, we will review two essential MRI tools used for studying and evaluating the pathophysiology of Allan-Herndon-Dudley Syndrome or MCT8 deficiency, a rare disease caused by inactivating mutations in the SLC16A2 gene, encoding for the thyroid hormone-specific transmembrane transporter MCT8. These two MRI techniques are time-of-flight magnetic resonance angiography (TOF-MRA) and diffusion tensor imaging (DTI).

A novel potential measurement indicator with objective and quantitative effect for trigeminal neuralgia: fractional anisotropy in MR-DTI.

To investigate the effect of diffusivity metrics of magnetic resonance diffusion tensor imaging (MR-DTI) in the assessment of treatment effects. MR-DTI examination for trigeminal neuralgia (TN) patients and the diffusivity metrics of the trigeminal ganglion (TG) were analyzed. Before and after the percutaneous stereotactic radiofrequency rhizotomy (PSR) operation, the treatment effect was assessed using pain scores and MR-DTI. The correlation between the diffusivity metrics of cranial nerve five (CNV) and visual analog scale (VAS) pain scores before and after treatment in TN patients was explored. In PSR patients, the fractional anisotropy (FA) of the affected TG is a significantly lower than that of the unaffected side (p < 0.01). After PSR, the diffusivity metrics on the bilateral TGs are not significantly different (p > 0.05). Following PSR treatment, both of the diffusivity metrics (FA) in the lowest area of the CNV and the VAS scores of TN patients show changes. Furthermore, diffusivity metric (FA) on the lowest area of the CNV preoperative is significantly negatively correlated with the VAS scores (p < 0.05). MR-DTI is capable of investigating the longitudinal changes of FA before and after radiofrequency treatment, and diffusivity metrics could be an independent reliable efficacy indicator for TN. The alteration of the diffusivity on TG may be correlated with the effect of radiofrequency treatment.

Thick and Short Fetal Corpus Callosum on Ultrasound: Added Value of Fetal Magnetic Resonance Diffusion Tensor Imaging With Tractography.

Thick fetal corpus callosum (CC) is a rare finding and its significance in isolation is not clear. In this retrospective study, we aim to gain insight into the microarchitecture of CC in a cohort of fetuses with thick and short CC (isolated or associated with mild extra-/intracranial abnormalities) as seen on ultrasound (US), by using prenatal magnetic resonance (MR) diffusion tensor imaging (DTI) with fiber tractography, thereby allowing better characterization for postnatal prognosis. Twelve fetuses met the inclusion criteria on US. The fetuses were further divided into group 1 (eight of twelve) with mild intra-/extracranial abnormalities or apparently isolated and group 2 (four of 12) with callosal lipoma (CL) on US. In all fetuses, both conventional MR imaging and DTI with tractography were done on 3T MRI. DTI fiber tractography showed an aberrant midline longitudinal supracallosal bundle (ASB) in all eight fetuses in group 1. Three of four fetuses in group 2 showed normal callosal architecture, and one showed an abnormal sigmoid bundle suggestive of partial agenesis of CC. We have for the first time demonstrated an ASB on MR DTI with tractography in eight of 12 fetuses with thick and short CC (isolated or mild associated intra-/extracranial abnormalities). Postnatally, ASB is reported to be associated with abnormal neurodevelopmental outcomes even in isolation and hence is important in counseling and prognosis. In fetuses with CLs, DTI would demonstrate normal or abnormal callosal architecture which is obscured by echogenicity and help in counseling.

Pancreatic Intraepithelial Neoplasia Revealed by Diffusion-Tensor MRI.

Detecting premalignant lesions for pancreatic ductal adenocarcinoma, mainly pancreatic intraepithelial neoplasia (PanIN), is critical for early diagnosis and for understanding PanIN biology. Based on PanIN's histology, we hypothesized that diffusion tensor imaging (DTI) and T2* could detect PanIN. DTI was explored for the detection and characterization of PanIN in genetically engineered mice (KC, KPC). Following in vivo DTI, ex vivo ultrahigh-field (16.4 T) MR microscopy using DTI, T2* was performed with histological validation. Sources of MR contrasts and histological features were investigated, including histological scoring for disease burden (lesion span) and severity (adjusted score). To test if findings in mice can be translated to humans, human pancreas specimens were imaged. DTI detected PanIN and pancreatic ductal adenocarcinoma in vivo (6 KPC, 4 KC, 6 controls) with high discriminative ability: fractional anisotropy (FA) and radial diffusivity with area under the curve = 0.983 (95% confidence interval: 0.932-1.000); mean diffusivity and axial diffusivity (AD) with area under the curve = 1 (95% confidence interval: 1.000-1.000). MR microscopy with histological correlation (20 KC/KPC; 5 controls) revealed that sources of MR contrasts likely arise from microarchitectural signatures: high FA, AD in fibrotic areas surrounding lesions, high diffusivities within cysts, and high T2* within lesions' stroma. The strongest histological correlations for lesion span and adjusted score were obtained with AD (R = 0.708, P < 0.001; R = 0.789, P < 0.001, respectively). Ex vivo observations in 5 human pancreases matched our findings in mice, revealing substantial contrast between PanIN and normal pancreas. DTI and T2* are useful for detecting and characterizing PanIN in genetically engineered mice and in the human pancreas, especially with AD and FA. These are encouraging findings for future clinical applications of pancreatic imaging.

Mechanism of Action of Mindfulness-Based Interventions for Pain Relief-A Systematic Review.

Background: Currently, no systematic evidence synthesis of the mechanism of action of mindfulness-based approaches exists for pain conditions. Aim: To identify and synthesize experimental and clinical studies examining aspects of the mechanism of action of mindfulness for pain relief. Methods: The following databases and search interfaces were searched: Embase (via Embase.com) and Medline (via PubMed). Additional references were identified via bibliographies of included studies. The following were the inclusion criteria applied: (1) original studies published in peer-reviewed journals, (2) in adult populations that (3) examined the mechanism of action of mindfulness meditation on pain outcomes or (4) provided conclusions regarding the potential mechanism of action of mindfulness meditation. The studies were selected by two independent reviewers. Discrepancies were resolved by discussion. Results: A total of 21 studies published in English met the inclusion criteria, of which 5 studies were clinical studies, which included patients with chronic pain, and 16 studies used experimental pain induction. The investigation into brain mechanisms through functional magnetic resonance imaging and diffusion tensor imaging revealed mindfulness meditation's ability to modulate brain activity, particularly in the anterior cingulate cortex, anterior insula, and orbitofrontal cortex, and to enhance structural and functional connectivity in regions associated with pain perception. Regarding the role of opioids, findings across five studies indicated that the analgesic effects of mindfulness are maintained even when opioid receptors are blocked, suggesting a nonopioidergic pathway for pain modulation. Pain perception studies highlighted that mindfulness practices foster pain acceptance and modify pain control beliefs, serving as key mediators in improving pain outcomes. For experienced versus novice mindfulness practitioners, results demonstrated that long-term practice enhances pain threshold and reduces pain unpleasantness through increased activity in salience and attentional control regions. Conclusion: This systematic review highlights mindfulness meditation as a multifaceted approach to pain management, utilizing mechanisms such as cognitive and emotional reappraisal, nonopioidergic pathways, and enhanced attention in control regions. It emphasizes the role of mindfulness in fostering pain acceptance and altering pain control perceptions, showcasing its broad impact on the neurological and experiential dimensions of pain. However, the predominance of studies on healthy subjects and methodological variations across experiments necessitates careful interpretation of the findings. The review calls for further research to explore the mechanisms of mindfulness in chronic pain populations more deeply, distinguishing the specific effects of mindfulness from nonspecific effects and expanding its applicability in clinical settings for chronic pain management.

Ultrahigh-resolution 7-Tesla anatomic magnetic resonance imaging and diffusion tensor imaging of ex vivo formalin-fixed human brainstem-cerebellum complex.

Brain cross-sectional images, tractography, and segmentation are valuable resources for neuroanatomical education and research but are also crucial for neurosurgical planning that may improve outcomes in cerebellar and brainstem interventions. Although ultrahigh-resolution 7-Tesla (7T) magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) reveal such structural brain details in living or fresh unpreserved brain tissue, imaging standard formalin-preserved cadaveric brain specimens often used for neurosurgical anatomic studies has proven difficult. This study sought to develop a practical protocol to provide anatomic information and tractography results of an ex vivo human brainstem-cerebellum specimen. A protocol was developed for specimen preparation and 7T MRI with image postprocessing on a combined brainstem-cerebellum specimen obtained from an 85-year-old male cadaver with a postmortem interval of 1 week that was stored in formalin for 6 months. Anatomic image series were acquired for detailed views and diffusion tractography to map neural pathways and segment major anatomic structures within the brainstem and cerebellum. Complex white matter tracts were visualized with high-precision segmentation of crucial brainstem structures, delineating the brainstem-cerebellum and mesencephalic-dentate connectivity, including the Guillain-Mollaret triangle. Tractography and fractional anisotropy mapping revealed the complexities of white matter fiber pathways, including the superior, middle, and inferior cerebellar peduncles and visible decussating fibers. 3-dimensional (3D) reconstruction and quantitative and qualitative analyses verified the anatomical precision of the imaging relative to a standard brain space. This novel imaging protocol successfully captured the intricate 3D architecture of the brainstem-cerebellum network. The protocol, unique in several respects (including tissue preservation and rehydration times, choice of solutions, preferred sequences, voxel sizes, and diffusion directions) aimed to balance high resolution and practical scan times. This approach provided detailed neuroanatomical imaging while avoiding impractically long scan times. The extended postmortem and fixation intervals did not compromise the diffusion imaging quality. Moreover, the combination of time efficiency and ultrahigh-resolution imaging results makes this protocol a strong candidate for optimal use in detailed neuroanatomical studies, particularly in presurgical trajectory planning.

Brain Function and Structure Changes in the Prognosis Prediction of Prolonged Disorders of Consciousness.

To observe the functional differences in the key brain areas in patients with different levels of consciousness after severe brain injury, and provide reference for confirming the objective diagnosis indicators for prolonged disorders of consciousness (pDoCs). This prospective study enrolled patients with pDoCs hospitalized in the department of rehabilitation medicine of our Hospital. Levels of consciousness and clinical outcomes were assessed according to diagnostic criteria and behavioral scales. Resting-state functional magnetic resonance imaging (rs-fMRI) and diffusion tensor imaging (DTI) of 30 patients with different levels of consciousness was performed. The patients were grouped as conscious or unconscious according to whether they regained consciousness during the 12-month follow-up. Thirty patients were enrolled, including eight with unresponsive wakefulness syndrome/vegetative state, eight with minimally conscious state, six with emergence from the minimally conscious state, and eight with a locked-in syndrome. There were 19 and 11 patients in the conscious and unconscious groups. Compared with the unconscious group, the left basal nucleus was activated in the conscious group, and there were significant differences in white matter fiber bundles. Correlations were observed between the regional homogeneity (ReHo) value of the cerebellum and the Glasgow coma scale score (r = 0.387, P = 0.038) and between the ReHo value of the left temporal and the coma recovery scale-revised score (r = 0.394, P = 0.035). The left insula and cerebellum might be important for regaining consciousness. The brain function activity and structural remodeling of the key brain regions and the activation level of the cerebellum are correlated with clinical behaviors and have potential application value for the prognosis prediction of pDoCs patients.

Unlocking Chemotherapy Success: The Role of Diffusion Tensor Imaging in Breast Cancer Treatment.

Background: This study investigates the role of Diffusion Tensor Imaging (DTI) in predicting the response to neoadjuvant chemotherapy (NAC) in patients with locally advanced breast cancer. Methods: A Diffusion Tensor Imaging magnetic resonance imaging (DTI MRI) sequence, evaluating water diffusion along tissue structures, was performed before and after two chemotherapy cycles. This study included 23 patients with 27 malignant masses, comparing changes in DTI parameters with Residual Cancer Burden (RCB) scores. Results: We found a significant correlation between changes in specific DTI parameters (e.g., λ2, FA, RA) and pathological response, suggesting that DTI could serve as a sensitive marker for early chemotherapy response. However, differences in sensitivity were observed between DTI sequences with 6 and 12 directions, indicating that 12-direction DTI may provide better diagnostic accuracy. The percentage change in DTI parameters, particularly FA, demonstrated a strong ability to predict pathological complete response (pCR) with high sensitivity. Conclusions: As a non-invasive tool, DTI has the potential to assess chemotherapy efficacy, although larger studies with standardized protocols are necessary to validate its clinical utility.

Magnetic resonance diffusion tensor imaging for detecting the cerebral microstructure changes in patients with CSVD-induced mild cognitive impairment.

Cerebral small vessel disease (CSVD)-induced mild cognitive impairment (MCI) has been linked to cognitive decline. Brain atrophy is considered the most common change in patients with MCI, which can be measured by diffusion tensor imaging (DTI). The study aimed to explore the relationship between DTI parameters and cognitive function in CSVD patients with MCI. This retrospective analysis involved 185 patients with CSVD, comprising 87 cases with MCI and 98 cases without MCI (NMCI). Analyses of demographic and clinical characteristics were conducted. DTI-measured fractional anisotropy (FA) and mean diffusivity (MD) in the hippocampus and entorhinal cortex regions were examined. The diagnostic values were determined using receiver-operative-curve (ROC) analysis, with the Youden index identifying optimum sensitivity and specificity. Correlations between Montreal cognitive assessment (MoCA) scores and FA or MD in patients with MCI were further assessed. No significant differences were observed in demographic and clinical characteristics between MCI and NMCI groups (all P > 0.05), except for diabetes prevalence (P = 0.011). Notably, the ROC analysis highlighted the diagnostic potential of FA, showing the maximum area under the curve values (hippocampus-left: 0.76; hippocampus-right: 0.66; entorhinal cortex-left: 0.62; entorhinal cortex-right: 0.64). MD exhibited a significant negative correlation with MoCA scores (hippocampus-left: r = -0.58, P < 0.001; hippocampus-right: r = -0.41, P < 0.001; entorhinal cortex-Lleft: r = -0.49, P < 0.001; entorhinal cortex-right: r = -0.27, P < 0.001), whereas FA showed a significant positive correlation (hippocampus-left: r = 0.51, P < 0.001; hippocampus-right: r = 0.31, P = 0.004; entorhinal cortex-left: r = 0.35, P < 0.001; entorhinal cortex-right: r = 0.38, P < 0.001). The study demonstrates the diagnostic value of DTI parameters in CSVD patients with MCI, emphasizing the associations between microstructural brain changes and cognitive function.NEW & NOTEWORTHY Diffusion tensor imaging (DTI)-measured fractional anisotropy and mean diffusivity demonstrate significant correlation with cognitive function, highlighting the diagnostic potential of DTI parameters in cerebral small vessel disease patients with mild cognitive impairment. Current findings emphasize the associations between microstructural brain changes and cognitive function.

A combined DTI-fMRI approach for optimizing the delineation of posteromedial versus anterolateral entorhinal cortex.

In the entorhinal cortex (EC), attempts have been made to identify the human homologue regions of the medial (MEC) and lateral (LEC) subregions using either functional magnetic resonance imaging (fMRI) or diffusion tensor imaging (DTI). However, there are still discrepancies between entorhinal subdivisions depending on the choice of connectivity seed regions and the imaging modality used. While DTI can be used to follow the white matter tracts of the brain, fMRI can identify functionally connected brain regions. In this study, we used both DTI and resting-state fMRI in 103 healthy adults to investigate both structural and functional connectivity between the EC and associated cortical brain regions. Differential connectivity with these regions was then used to predict the locations of the human homologues of MEC and LEC. Our results from combining DTI and fMRI support a subdivision into posteromedial (pmEC) and anterolateral (alEC) EC and reveal a confined border between the pmEC and alEC. Furthermore, the EC subregions obtained by either imaging modality showed similar distinct whole-brain connectivity profiles. Optimizing the delineation of the human homologues of MEC and LEC with a combined, cross-validated DTI-fMRI approach allows to define a likely border between the two subdivisions and has implications for both cognitive and translational neuroscience research.

Multimodal brain age indicators of internalising problems in early adolescence: A longitudinal investigation

BackgroundAdolescence is a time of increased risk for the onset of internalising problems, particularly in females. However, how individual differences in brain maturation relate to the increased vulnerability for internalising problems in adolescence remains poorly understood due to a scarcity of longitudinal studies. MethodsUsing Adolescent Brain Cognitive Development (ABCD) Study data, we examined longitudinal associations between multimodal brain age and youth internalising problems. Brain age models were trained, validated, and tested independently on T1-weighted (T1; N=9523), diffusion tensor (DTI; N=8834), and resting-state functional (rs-fMRI; N=8233) MRI data at baseline (Mage= 9.9 years) and 2-year follow-up (Mage= 11.9 years). Self-reported internalising problems were measured at 3-year follow-up (Mage= 12.9 years) using the Brief Problem Monitor. ResultsLatent change score models demonstrated that although brain age gap (BAG) at baseline was not related to later internalising problems, an increase in BAG between timepoints was positively associated with internalising problems at 3-year follow-up in females but not males. This association between an increasing BAG and higher internalising problems was observed in the T1 (β = 0.067, SE = 0.050, pFDR = 0.020) and rs-fMRI β = 0.090, SE = 0.025, pFDR = 0.007) models but not DTI (β=-0.002, SE=0.053, pFDR = 0.932), and remained significant when accounting for earlier internalising problems. ConclusionsA greater increase in BAG in early adolescence may reflect the heightened vulnerability shown by female youth to internalising problems. Longitudinal research is necessary to understand if this increasing BAG signifies accelerated brain development and its relationship to the trajectory of internalising problems throughout adolescence.