Altered states of consciousness in epilepsy: a DTI study of the brain

To evaluate cyclic changes of fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values of normal uterus in different age groups during the menstrual cycle, and the correlation with serum female hormone levels. 29 normal volunteers accepted diffusion tensor imaging of the uterus on menstrual phase (MP), follicular phase (FP), ovulatory phase (OP) and luteal phase. FA and ADC values of different uterine layers on midsagittal images were measured. Differences between two age groups during the menstrual cycle were evaluated using liner mixed models and one-way analysis of variance. Pearson correlation analysis compared variation of FA and ADC values with serum female hormone levels measured in MP. During menstrual cycle, endometrial FA values declined, whereas ADC values increased with significant differences (p < 0.05). Serum oestradiol (E) levels correlated moderately with variations of FA values between MP-FP (p = 0.045; r = 0.389) and MP-OP (p = 0.008; r = 0.511). FA and ADC values of junctional zones showed no significant difference (p > 0.05) as well as FA values of myometrium (p = 0.0961), while ADC values of myometrium showed significant increase from menstrual phase to luteal phase (p < 0.05). FA and ADC values of uterine three zonal structures showed significant differences (p < 0.05) at each phase during the menstrual cycle. No significant difference of FA and ADC values was found between age groups (p > 0.05). Dynamic changes of uterine FA and ADC values were observed during menstrual cycle. Variation of FA values between MP-FP, MP-OP correlated moderately with serum E levels. No publications on the relationship between FA and ADC values and the female hormone levels were found; our study prospectively investigated the cyclic changes of FA and ADC values of the normal uterus and the correlation with the basic serum female hormone levels in MP.

[This corrects the article DOI: 10.1371/journal.pone.0160115.].

ObjectivesTo evaluate the feasibility of differentiating between acute pancreatitis (AP) and healthy pancreas using diffusion tensor imaging (DTI) and correlate apparent diffusion coefficient (ADC) /fractional anisotropy (FA) values with the severity of AP.Material and Methods66 patients diagnosed with AP and 20 normal controls (NC) underwent DTI sequences and routine pancreatic MR sequences on a 3.0T MRI scanner. Average ADC and FA values of the pancreatic were measured. Differences of FA and ADC values between the AP group and the NC group with AP and healthy pancreas were compared by two-sample independent t-test. The severity of AP on MRI was classified into subgroups using MR severity index (MRSI), where the mean FA and ADC values were calculated. Relationship among the FA values, ADC values and MRSI were analyzed using Spearman's rank correlation coefficients.ResultsThe pancreatic mean ADC value in the AP group (1.68 ± 0.45×10−3mm2/s) was significantly lower than in the NC group (2.09 ± 0.55×10−3mm2/s) (P = 0.02); the same as mean FA value (0.39 ± 0.23 vs 0.54 ± 0.12, P = 0.00). In the subgroup analysis, the pancreatic ADC and FA value of edema AP patients was significantly higher than necrosis AP patients with P = 0.000 and P = 0.001respectively. In addition, as severity of pancreatitis increased according to MRSI, lower pancreatic ADC (r = -0.635) and FA value (r = -0.654) were noted.ConclusionBoth FA and ADC value from DTI can be used to differentiate AP patients from NC. Both ADC and FA value of pancreas have a negative correlation with the severity of AP.

The purpose of this study is to investigate the correlation of apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values with fatty infiltration in the thigh muscles of patients with Duchenne muscular dystrophy (DMD) using diffusion-tensor imaging (DTI). Twenty-one boys with DMD were recruited. The grade of fatty infiltration and the ADC and FA values of four thigh muscles (rectus femoris, semitendinosus, sartorius, and gracilis) were measured, and the FA and ADC values were compared with the grade of fatty infiltration. Twenty age-matched healthy boys were enrolled as the control group. The differences in the ADC and FA values of the thigh muscles between patients with DMD and the control group were compared. The patients with DMD showed lower FA values and higher ADC values in all measured muscles when compared with the control group. The FA and ADC values were correlated with the grade of fatty infiltration. For the rectus femoris muscle, r = -0.753 and p = 0.007 for FA, and r = 0.685 and p = 0.001 for ADC. For the semitendinosus muscle, r = -0.621 and p = 0.041 for FA, and r = 0.705 and p = 0.021 for ADC. For the sartorius muscle, r = -0.662 and p = 0.027 for FA, and r = 0.701 and p = 0.017 for ADC. For the gracilis muscle, r = -0.618 and p = 0.043 for FA, and r = 0.695 and p = 0.022 for ADC. Damage to the thigh muscles in patients with DMD can be detected by ADC and FA values using DTI. DTI can be used to assess the severity of the disease.

Objective To study the vascular compression on the ponline cistern of the trigeminal with magnetic resonance diffusion tensor imaging (DTI) and explore the clinical application value of DTI.Methods Sixty patients who were conformed by operation as having trigeminal neuralgia (TN) caused by responsible vascular compression (TN group) and 50 healthy volunteers (control group) were performed conventional MRI and horizontal DTI to measure the apparent diffusion coefficient (ADC)value and fractional anisotropy (FA) value. Results The ADC value and FA value of trigeminal nerve in control group were (1.76±0.98)×10-3 mm2/s, and (0.40±18), respectively, no significant differences of the ADC value and FA value between the left and right trigeminal nerves were found (P>0.05). The ADC and FA values of the trigeminal nerve among the controls, patients with mild or severe compression and the patients with compression combined with neuratrophia were statistically difrerent(P<0.05). The ADC value in the oppression region was increased in 28 patients and unchanged in 4; the average ADC value in the NT group was significantly higher than that in the control group. FA value in the oppression region decreased in 15 patients, unchanged in11 and increased in 5; the average FA value in the NT group was lower than that in the control group. Conclusion DTI has its value in determining the vascular compression of the trigeminal nerve; the greater the degree of trigeminal nerve compression is, the higher the ADC value and the lower the FA value are. Key words: Trigeminal neuralgia; Vascular compression; Magnetic resonance imaging; Diffusion tensor imaging

The microstructure of the spinal cord in syringomyelia has not been well studied. The aim of this study was to evaluate the microstructure of the cervical cord in patients with syringomyelia using diffusion tensor imaging (DTI) and to investigate the association between DTI parameters and the size of the syrinx cavity. Thirty patients with syringomyelia and 11 age-matched controls were included in this study. DTI and T1/T2-weighted MRI were used to estimate spinal microstructure. The patients were divided into a clinical symptom group (group A) and a non-clinical symptom group (group B) according to ASIA assessments. The fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values (mm2/s) were measured and compared between patients and controls. Correlation between FA/ADC and the size of the syrinx cavity was examined with a bivariate analysis. FA values were lower (P < 0.000) and ADC values were higher (P < 0.000) compared to the controls at the level of all syrinxes examined in patients with syringomyelia; both FA values and ADC values reached normal values either above or below the syrinx levels (all P > 0.05). FA values and ADC values at all cervical levels were not significantly different either in controls or outside of the syrinx (all P > 0.05). FA values of group A was significantly lower than those of group B (P < 0.000). There was a negative association between FA values and the size of syrinx cavity, and a positive association between ADC values and the size of syrinx cavity (FA: P < 0.05, ADC: P < 0.05). The microstructure of the cervical spinal cord is different across all patients with syringomyelia. DTI is a promising tool for estimating quantitative pathological characteristics that are not visible with general MRI.

Objective: To measure diffusion tensor imaging (DTI) parameters in healthy adults and analyze the distribution characteristics and influencing factors. Methods: In this case-series study, high resolution diffusion tensor imaging was performed on the anterior visual pathway in 38 healthy adults at the physical examination center of Fuzhou General Hospital from November 2015 to May 2016 using 3.0T magnetic resonance imaging. The fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values were measured on the anterior visual pathway, including the bilateral optic nerve center, midpoint of chiasma, and the midpoint of optic tract. The anterior visual pathway fiber bundle was reconstructed by diffusion tensor tracking (DTT) to observe the morphology of the anterior optic fiber bundle. Pearson correlation, independent samples t-test, and one-way analysis of variance were used to analyze the data. Results: The structure of the DTI sequence diagram of FA, FA color encoding, and ADC can distinguish the anterior visual pathway. DTT can be used to track with 3D effects the white matter fiber bundle structure of optic chiasma. The FA and ADC values of the midpoint of optic chiasma were 0.491±0.075, and 1.267±0.204×10-3/mm2. There was a significant negative correlation between FA and ADC (r=-0.642, P<0.001). FA and ADC values were independent of gender and age. Differences between FA and ADC in optic nerve, optic tract, or optic chiasma were significant (F=11.575, P<0.001; F=5.024, P<0.001). The FA value was the smallest (P<0.001) in the optic chiasma, and the ADC value was the largest at the same location (P<0.001). Conclusions: High resolution DTI parameters FA and ADC are sensitive and reliable in the anterior visual pathway of healthy adults. The high resolution DTI technique can satisfactorily display small deformations of the anterior visual pathway fiber bundle structure. Attention should be paid to the influence of different positions of the anterior visual pathway in quantitative analyses. Key words: anterior visual pathway; magnetic resonance spectroscopy; diffusion tensor imaging; diffusion tensor tracking; adults

Objective: To determine whether apparent diffusion coefficient (ADC) values and fractional anisotropy (FA) values can detect early pathological involvement in multiple system atrophy (MSA), and be used to differentiate MSA-P...

Objective To survey the apparent diffusion coefficient (ADC) value and fractional anisotropy (FA) value ofpontine cistern section of the trigeminal nerve, and understand the characteristics of various parameters of trigeminal nerve pontine cistern section. Methods The distances from pontine cistern section of the trifacial nerve to 0, 3, 6 and 9 mm of brain stem in 50 healthy volunteers were recorded, and fusion images of magnetic resonance diffusion tensor imaging (DTI) with B-TFE or THRIVE were achieved to improve the spatial resolution of the pontine cistern section of the trifacial nerve; their ADC value and FA value were recorded, separately. Tracing image formation was noted in the pontine cistern section of the trigeminal or trifacial nerve. Results The ADC and FA results of the left side and right flank of pontine cistern section of the trifacial nerve in these healthy volunteers were not statistically different (P＜0.05). The closer to the brain stem, the more asymmetrical tendency of distance from pontine cistern section of the trifacial nerve to 0, 3, 6 and 9 mm of brain stem between both sides. DTI indicated that the ADC values between each 2 distances from pontine cistern section of the trifacial nerve to 0, 3, 6 and 9 mum of brain stem between both sides were significantly different: the ADC values increased along with the distance elevating gradually, but rotated suddenly at the line of 6-9 mm. The FA value increased in 0-6 mm along with the distance reducing gradually, and the neighboring 2 distances had remarkably statistical difference, but the FA value no longer obviously changed from the line of 6-9 mm. Conclusion DTI can distinguish the two-sided trigeminal nerve brain pond section clearly, and may realize each item of DTI. Regular changes are noted in FA and ADC values along with the different distances from pontine cistern section of the trifacial nerve to 0, 3, 6 and 9 mm of brain stem,indicating that DTI enjoys perspective in being clear about the discrimination of cranial nerve CNS section, the change-over portion and the PNS section, and in detecting the cranial nerve vascular compression. Key words: Diffusion tensor imaging; Apparent diffusion coefficient; Fractional Anisotrop

To determine whether there is adifference in apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values in white matter pathways in the subacute period after COVID-19 infection and to evaluate the correlation between diffusion tensor imaging (DTI) metrics and laboratory findings. The study included 64 healthy controls and 91patients. Patients were classified as group1 (all patients, n = 91), group2 (outpatients, n = 58), or group3 (inpatients, n = 33). The ADC and FA values were calculated from 10distinct neuroanatomic localizations; DTI values were compared between groups. Decreased FA values in the cingulum, corpus callosum splenium and genu (CCS-CCG), forceps major, inferior fronto-occipital fasciculus (IFOF), and middle cerebellar peduncle (MCP) observed in group1 compared with the control group. Group1 showed elevated ADC values in CCG. Lower FA and higher ADC values in CCG were shown in group3. The FA values for CCS, IFOF, and MCP in group3 were lower than those in the control group. Group3 had the highest ADC values in the CCS. Additionally, the FA values of the CCG were lower in group3 than in group2. Oxygen saturation levels and FA values in the CCG and SFOF exhibited apositive correlation. We speculate that DTI changes in white matter pathways may be associated with axonal damage and demyelination due to impaired white matter integrity following COVID-19 infection during the subacute period. Our study showed with DTI findings that there is microstructural damage in white matter pathways in the subacute period of COVID-19 infection and that this damage is related to oxygen saturation levels. Many studies in the literature show that microstructural damage in white matter pathways can lead to clinical neurocognitive dysfunction. We suggest that these cases require more comprehensive studies investigating whether chronic white matter damage is reversible and examining its relationship with neurocognitive dysfunctions in the future. Neurological involvement is not rare in COVID-19 infection. We examined various white matter pathways with DTI during the subacute period of COVID-19 infection. We showed changes in DTI parameters indicating adecrease in white matter integrity and microstructural damage in the subacute period follow-up of cases with COVID-19. We found that there was apositive correlation between oxygen saturation levels and decreased FA values in white matter tracts.

The aim of this study is to evaluate if diffusion tensor imaging (DTI) can distinguish the disease process of radiation-induced brain injury when combined with apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values. Twenty-one rabbits received irradiation of 100 Gy in the right brain hemisphere. Twelve rabbits were screened with magnetic resonance imaging (MRI) and DTI before radiation, and imaged at every week until week 9 following radiation. The rabbits that had MRI were euthanized at week 9 for histologic evaluation, while other nine rabbits without MRI were randomly killed for histologic evaluation at weeks 2, 4 and 6, respectively. From the DTI, the ADC and FA values were measured, and rADC and rFA were calculated. After radiation, the trend of the ADC value can be divided into three stages. In the first stage, the ADC value of the target tissues gradually decreased. In the second stage, the ADC value of white matter in the target tissues showed a recovery trend, back to the initial level similar to that in contralateral. In the third stage, the ADC value of white matter in the target tissue continues to increase over the ADC value of baseline and contralateral white matter. The FA value of radiation-targeted area showed continuous decreasing tendency. Pathological evaluation showed the different features in three stages. DTI can distinguish the different disease stages when combined with the ADC and FA values.

Study DesignRetrospective observational study.PurposeTo examine fractional anisotropy (FA) values and apparent diffusion coefficient (ADC) values of damaged nerves to discriminate between lumbar intraspinal stenosis (IS) and foraminal stenosis (FS) using diffusion tensor imaging (DTI)Overview of LiteratureIt is important in the selection of surgical procedure to discriminate between lumbar IS and FS, but such discrimination is difficult.MethodsThere were 9 cases of IS, 7 cases of FS, and 5 healthy controls. The regions of interest were established in the lumbar intraspinal zone (Iz), nerve root (N), and extraforaminal zone (Ez). The FA and ADC values were measured on the affected and unaffected sides of the nerves. The FA ratio and the ADC ratio were calculated as the affected side/unaffected side ×100 (%).ResultsIn the Ez, the FA value was significantly lower in FS than in IS (p<0.01). FA ratio was significantly lower in FS than in IS for the Ez (p<0.01). In the Iz, the ADC value was significantly higher in IS than FS (p<0.01). ADC ratio was significantly higher in FS than in IS for the N and Ez (p<0.05). For the Ez, receiver operating characteristic analysis of parameters revealed that the FA values showed a higher accuracy for the diagnosis of FS than the ADC values, and the FA value cut-off value was 0.42 (sensitivity: 85.7%, false positive: 11.1%) and the FA ratio cut-off value was 83.9% (sensitivity: 85.7%, false positive: 22.2%).ConclusionsThe low FA value in the extraforaminal zone suggests the presence of foraminal stenosis. When the FA value and FA ratio cut-off value were established as 0.42 and 83.9%, respectively, the accuracy was high for the diagnosis of foraminal stenosis. It may be possible to use DTI parameters to help in the discrimination between IS and FS.

To investigate the characteristics of diffusion tensor imaging (DTI) of the central nervous system in children with Tourette syndrome (TS).Fifteen children with TS (TS group) and 15 normal children (control group) were studied, and all of them underwent DTI. The apparent diffusion coefficient (ADC) and fractional anisotropy (FA) parameters were calculated using the DTIStudio software. The region of interest was delineated manually. The ADC and FA values of the bilateral caudate nucleus, bilateral globus pallidus, bilateral putamen, bilateral thalamus, and bilateral frontal lobe white matter were measured using the region of interest editor software. The differences of FA values and ADC values between the same brain areas were compared. The associations between ADC, FA values and Yale Global Tic Severity Scale (YGTSS) scores were evaluated by Pearson correlation analyses.The FA values of left globus pallidus and left thalamus were significantly lower in the TS group than in the control group (P < .05), while the ADC values of the right caudate nucleus and bilateral thalamus were significantly higher in the TS group than in the control group (P < .05). The decrease in FA in the left thalamus significantly correlated with the YGTSS score (r = 0.692; P < .05). No correlation was found between FA and ADC values in other brain regions and the YGTSS score (P > .05).After the DTI analyses, abnormalities were found in the left globus pallidus, right caudate nucleus, and bilateral thalamus in children with TS. Especially the changes in the left thalamus structure was crucial in the pathophysiological clock of TS.

ObjectiveThis study investigates the correlation between magnetic resonance diffusion tensor imaging (DTI) parameters and biochemical composition in degenerative intervertebral disc nucleus pulposus tissue, offering a potential reference for the clinical diagnosis and efficacy evaluation of intervertebral disc degeneration.MethodsHuman lumbar intervertebral disc nucleus pulposus tissue samples were collected via full endoscopic minimally invasive surgery. DTI was employed to quantitatively measure fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values in the degenerative nucleus pulposus, examining the relationship between Pfirrmann grading and these DTI parameters. Western blotting was used to detect the expression levels of aquaporin 1 (AQP1) and aquaporin 3 (AQP3) in the degenerative tissue. The glycosaminoglycan (GAG) content was quantified using the dimethylmethylene blue (DMMB) colorimetric assay, and collagen content was assessed with the Sircol soluble collagen assay kit. The relationship between Pfirrmann grading and biochemical composition was also analyzed. Finally, correlation analysis was performed between the FA and ADC values from the human nucleus pulposus tissue and their GAG and collagen contents.ResultsA total of 39 patients (19 males, 20 females) with lumbar disc herniation (LDH), averaging 54.41 years of age, were included. As the degree of Pfirrmann degeneration increased, FA values rose, while ADC values continuously declined. Concurrently, as degeneration progressed, expression of AQP1 and AQP3 proteins decreased, GAG content significantly diminished, and collagen content increased. FA values exhibited a moderate negative correlation with GAG content (r = -0.5974, P < 0.0001) and a strong positive correlation with collagen content (r = 0.8694, P < 0.0001). ADC values showed a moderate positive correlation with GAG content (r = 0.6873, P < 0.0001) and a strong negative correlation with collagen content (r = -0.8502, P < 0.0001).ConclusionThe FA and ADC values derived from magnetic resonance DTI, along with the protein expression levels of AQPs, can reflect the severity of intervertebral disc degeneration to a certain extent. Additionally, the content of glycosaminoglycans and collagen in the nucleus pulposus of the intervertebral disc correlates with the FA and ADC values of the DTI parameters. Therefore, magnetic resonance DTI quantitative imaging provides a means to assess the biochemical composition changes within the intervertebral discs, offering valuable insights for the clinical diagnosis and evaluation of therapeutic efficacy in intervertebral disc degenerative diseases.Trial registrationChinese Clinical Trial Registry, ChiCTR2000041151, Registered on 19 December, 2020, https://www.chictr.org.cn/showproj.html?proj=206119.

ObjectiveTo investigate changes in DTI (Diffusion Tensor Imaging) parameters in brainstem subcortical auditory pathways after Gamma Knife Radiosurgery (GKR) in patients with intracanalicular vestibular schwannoma (ICVS) and to analyze the relationship between tumor volume and ADC (apparent diffusion coefficient) and FA (fractional anisotropy) values.MethodSeventeen patients with ICVS were evaluated before and after GKR. ADC and FA values of the lateral lemniscus (LL) and inferior colliculus (IC) and tumor volume were calculated. Patients who responded to GKR were classified as Group 1 and those who did not respond adequately as Group 2. The relationship between ADC and FA values and changes in tumor volume were analyzed.ResultsTumor volume significantly decreased after GKR. ADC values obtained from the tumor increased after GKR (p:0.002). There was no significant difference in LL and IC before and after GKR in terms of FA and ADC values (n:17). There was a positive correlation between response to treatment and contralateral LL ADC values after GKR (p=0.005, r:0.652). There was a negative correlation between contralateral IC FA values after GKR and response to treatment (p=0.017, r: -0.568). There was a significant difference between Groups 1 and 2 in regards to contralateral LL ADC (p=0.03) and IC FA values (p=0.017).ConclusionSince the cochlear nerve and subcortical auditory pathways have low regeneration potential after nerve damage, ADC and FA changes in LL and IC may be explained with the presence of intracanalicular tumors prior to GKR. Since GKR does not cause additional damage to the subcortical auditory pathways at the brainstem level, we think that GKR is a noninvasive treatment method that can be used safely in patients with ICVS.