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1.
Medicine (Baltimore) ; 100(35): e27015, 2021 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-34477131

RESUMO

ABSTRACT: Physical exercise leads to structural changes in the brain. However, it is unclear whether the initiation or continuous practice of physical exercise causes this effect and whether brain connectivity benefits from exercise. We examined the effect of 6 months of exercise on the brain in participants who exercise regularly (n = 25) and in matched healthy controls (n = 20). Diffusion tensor imaging brain scans were obtained from both groups. Our findings demonstrate that regular physical exercise significantly increases the integrity of white matter fiber tracts, especially those related to frontal function. This implies that exercise improves brain connectivity in healthy individuals, which has important implications for understanding the effect of fitness programs on the brains of healthy subjects.


Assuntos
Exercício Físico/fisiologia , Voluntários Saudáveis/estatística & dados numéricos , Substância Branca/fisiopatologia , Adulto , Imagem de Tensor de Difusão/métodos , Feminino , Humanos , Masculino , Substância Branca/diagnóstico por imagem
2.
Medicine (Baltimore) ; 100(31): e26840, 2021 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-34397854

RESUMO

RATIONALE: We report on a patient whose arcuate fasciculus (AF) and corticobulbar tract (CBT) recovered following an infarct in the middle cerebral artery (MCA) territory, demonstrated on serial diffusion tensor tractography (DTT). PATIENT CONCERNS: The patient showed moderate conduction aphasia on the Western Aphasia Battery with an aphasia quotient of 46.5‰ (spontaneous speech: 35.0‰, auditory comprehension: 36.0‰, and naming: 53.1‰) at 1 month after onset. His aphasia improved with an aphasia quotient of 49‰ (spontaneous speech: 71.0‰, auditory comprehension: 52.0‰, and naming: 59.0‰) at 10 months after onset. DIAGNOSIS: A 44-year-old right-handed male patient presented with aphasia and quadriplegia, which occurred at the onset of an infarct in the left MCA territory. INTERVENTION: Diffusion tensor imaging data were acquired twice (1 month and 10 months after onset). OUTCOMES: On one-month DTT, the discontinuation of the left AF and severe narrowing of the right CBT were observed. However, on ten-month DTT, the left AF was connected to the opposite AF by a new tract that passed through the splenium of corpus callosum, and the right CBT had become thicker. LESSONS: We believe that our results suggest a recovery mechanism of injured AF and CBT in stroke patients.


Assuntos
Afasia , Encéfalo , Área de Broca , Infarto da Artéria Cerebral Média , Área de Wernicke , Adulto , Afasia/diagnóstico , Afasia/etiologia , Afasia/reabilitação , Encéfalo/irrigação sanguínea , Encéfalo/diagnóstico por imagem , Imagem de Tensor de Difusão/métodos , Humanos , Infarto da Artéria Cerebral Média/diagnóstico , Infarto da Artéria Cerebral Média/fisiopatologia , Infarto da Artéria Cerebral Média/reabilitação , Masculino , Vias Neurais/patologia , Vias Neurais/fisiopatologia , Reabilitação Neurológica/métodos , Tratos Piramidais/patologia , Recuperação de Função Fisiológica , Fonoterapia/métodos , Resultado do Tratamento
3.
BMC Neurol ; 21(1): 320, 2021 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-34404371

RESUMO

BACKGROUND: The cerebellum receives afferent signals from spinocerebellar pathways regulating lower limb movements. However, the longitudinal changes in the spinocerebellar pathway in the early stage of unilateral supratentorial stroke and their potential clinical significance have received little attention. METHODS: Diffusion tensor imaging and Fugl-Meyer assessment of lower limb were performed 1, 4, and 12 weeks after onset in 33 patients with acute subcortical infarction involving the supratentorial areas, and in 33 healthy subjects. We evaluated group differences in diffusion metrics in the bilateral inferior cerebellar peduncle (ICP) and analyzed the correlation between ICP diffusion metrics and changes to the Fugl-Meyer scores of the affected lower limb within 12 weeks after stroke. RESULTS: Significantly decreased fractional anisotropy and increased mean diffusivity were found in the contralesional ICP at week 12 after stroke compared to controls (all P < 0.01) and those at week 1 (all P < 0.05). There were significant fractional anisotropy decreases in the ipsilesional ICP at week 4 (P = 0.008) and week 12 (P = 0.004) compared to controls. Both fractional anisotropy (rs = 0.416, P = 0.025) and mean diffusivity (rs = -0.507, P = 0.005) changes in the contralesional ICP correlated with changes in Fugl-Meyer scores of the affected lower limb in all patients. CONCLUSIONS: Bilateral ICP degeneration occurs in the early phase of supratentorial stroke, and diffusion metric values of the contralesional ICP are useful indicators of affected lower limb function after supratentorial stroke.


Assuntos
Cerebelo/diagnóstico por imagem , Infarto Cerebral/diagnóstico por imagem , Imagem de Tensor de Difusão/métodos , Extremidade Inferior/diagnóstico por imagem , Acidente Vascular Cerebral/diagnóstico por imagem , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Recuperação de Função Fisiológica
4.
Clin Ter ; 172(4): 315-321, 2021 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-34247214

RESUMO

Background: This study aimed to determine the diagnostic per-formance of fractional anisotropy (FA) and mean diffusivity (MD) values for glioma grading. Conclusion: The tMD, rMDt/w, and rFAp/w values represent useful indices for the differentiation between LGG and HGG. The combination of these indices can improve diagnostic specificity. Methods: A total of 42 patients who underwent biopsy or surge-ry and were histologically diagnosed with glioma from September 2019 to December 2020 were enrolled in this retrospective study. Diffusion tensor imaging (DTI) and conventional magnetic resonance imaging (MRI) were performed preoperatively using 3 Tesla MRI in all cases. The FA and MD values were measured in the solid portion of the tumor, the peritumoral area, and the normal white matter. The diagnostic performances of the absolute and relative FA and MD values for glioma grading were analyzed using the receiver operating characteristic (ROC) curve. Results: The MD value in the solid portion of the tumor (tMD), the MD value of the solid portion of the tumor relative to that in the normal white matter (rMDt/w), and the FA value for the peritumoral region relative to that of the normal white matter (rFAp/w) showed significant differences between the low-grade (LGG) and high-grade glioma (HGG) groups. The combination of these three parameters provided the largest area under the curve value of 89% with sensitivity, specificity, accuracy, negative predictive, and positive predictive values of 72%, 100%, 81%, 62%, and 100%, respectively, for distinguishing between the LGG and HGG groups.


Assuntos
Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/fisiopatologia , Imagem de Difusão por Ressonância Magnética/métodos , Imagem de Tensor de Difusão/métodos , Glioma/diagnóstico , Glioma/fisiopatologia , Gradação de Tumores/métodos , Adolescente , Adulto , Anisotropia , Neoplasias Encefálicas/cirurgia , Criança , Feminino , Glioma/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Cuidados Pré-Operatórios , Curva ROC , Estudos Retrospectivos , Sensibilidade e Especificidade , Adulto Jovem
5.
World Neurosurg ; 152: 124-136, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34147690

RESUMO

BACKGROUND: Diffusion tensor imaging (DTI) application in Chiari malformation type I (CMI) is still poorly defined. This study aimed to systematically review the literature and propose perspectives toward the clinical application of DTI in CMI. METHODS: PubMed and Embase were searched for English-language articles published until October 20, 2020. Clinical studies and case series, evaluating fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), or radial diffusivity values in patients with CMI, were included. RESULTS: Eight articles were included. Lower FA values were found at the syrinx level, which decreased with syrinx extent and intensity of symptoms, reflecting myelopathy severity. Decreased AD and MD in the middle cerebellar peduncles in symptomatic patients with CMI might explain the presence of cerebellar signs. Increased FA in various supratentorial structures positively correlated with pain severity. Worse performance in neuropsychological tests correlated with decreased FA, increased MD, and radial diffusivity, reflecting axonal degeneration. Postoperative FA decrease in the brainstem compression area reflects successful decompression. A positive correlation was found between the extent of tonsillar ectopia and increased FA, MD, and AD values, which could act as an early indicator of acute brainstem compression. CONCLUSIONS: DTI might provide a valuable insight into the neurobiological foundation of symptomatic CMI presentation. The severity of white matter injury evident on DTI could serve as a reliable predictor of postoperative outcomes, therefore facilitating selection of appropriate surgical candidates. Postinterventional DTI reassessment might enable differentiation between unsuccessful surgical technique and irreversible myelopathy. The extent of tonsillar ectopia reflects the severity of microstructural brainstem injury.


Assuntos
Malformação de Arnold-Chiari/diagnóstico por imagem , Imagem de Tensor de Difusão/métodos , Neuroimagem/métodos , Humanos
6.
Int J Mol Sci ; 22(10)2021 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-34069159

RESUMO

There has been an increasing prevalence of neurodegenerative diseases with the rapid increase in aging societies worldwide. Biomarkers that can be used to detect pathological changes before the development of severe neuronal loss and consequently facilitate early intervention with disease-modifying therapeutic modalities are therefore urgently needed. Diffusion magnetic resonance imaging (MRI) is a promising tool that can be used to infer microstructural characteristics of the brain, such as microstructural integrity and complexity, as well as axonal density, order, and myelination, through the utilization of water molecules that are diffused within the tissue, with displacement at the micron scale. Diffusion tensor imaging is the most commonly used diffusion MRI technique to assess the pathophysiology of neurodegenerative diseases. However, diffusion tensor imaging has several limitations, and new technologies, including neurite orientation dispersion and density imaging, diffusion kurtosis imaging, and free-water imaging, have been recently developed as approaches to overcome these constraints. This review provides an overview of these technologies and their potential as biomarkers for the early diagnosis and disease progression of major neurodegenerative diseases.


Assuntos
Biomarcadores , Encéfalo/diagnóstico por imagem , Imagem de Difusão por Ressonância Magnética/métodos , Doenças Neurodegenerativas/diagnóstico por imagem , Doença de Alzheimer/diagnóstico por imagem , Biomarcadores/análise , Encéfalo/patologia , Imagem de Tensor de Difusão/métodos , Diagnóstico Precoce , Humanos , Processamento de Imagem Assistida por Computador/métodos , Neuritos , Doença de Parkinson/diagnóstico por imagem
7.
Br J Radiol ; 94(1122): 20201374, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33989037

RESUMO

OBJECTIVE: To explore the feasibility of diffusion kurtosis imaging (DKI) in differentiating different types of renal cell carcinoma (RCC). METHODS: 36 patients with clear cell RCC (CCRCC, low-grade,n = 20 and high-grade, n = 16), 19 with papillary RCC, 11 with chromophobe RCC, and 9 with collecting duct carcinoma (CDC) were examined with DKI technique. b values of 0, 500 and 1000 s/mm2 were adopted. The DKI parameters, i.e., mean diffusivity (MD), mean kurtosis (MK), kurtosis anisotropy (KA), radial kurtosis (RK) and signa-to-noise ration (SNR) of DKI images at different b values were used. RESULTS: The mean SNRs of DKI images at b = 0, 500 and 1000 s/mm2 were 32.8, 14.2 and 9.18, respectively. For MD parameter, a significant higher value was shown in CCRCC than those of papillary RCC, chromophobe RCC and CDC (p < 0.05). In addition, both chromophobe RCC and CDC have larger MD values than papillary RCC (p < 0.05), however, there was no significant differences between chromophobe RCC and CDC (p > 0.05). For MK, KA and RK parameters, a significant higher value was shown in papillary RCC than those of CCRCC, chromophobe RCC and CDC (p < 0.05). Moreover, both chromophobe RCC and CDC have significantly larger values of MK, KA and RK than CCRCC (p < 0.05). CONCLUSION: Our preliminary study demonstrated significant differences in the DKI parameters between the subtypes of RCCs, given an adequate SNR of DKI images. ADVANCES IN KNOWLEDGE: 1.The MD value is the best parameter to distinguish CCRCC from other RCCs.2.The MK, KA and RK values are the best parameters to distinguish papillary RCC from other RCCs.3.DKI is able to provide images with sufficient SNRs in kidney disease.


Assuntos
Carcinoma de Células Renais/diagnóstico por imagem , Imagem de Tensor de Difusão/métodos , Neoplasias Renais/diagnóstico por imagem , Adulto , Idoso , Anisotropia , Carcinoma de Células Renais/patologia , Diagnóstico Diferencial , Estudos de Viabilidade , Feminino , Humanos , Neoplasias Renais/patologia , Masculino , Pessoa de Meia-Idade , Gradação de Tumores , Razão Sinal-Ruído
8.
Aging (Albany NY) ; 13(9): 12410-12430, 2021 04 30.
Artigo em Inglês | MEDLINE | ID: mdl-33930871

RESUMO

BACKGROUND: The underlying white matter impairment in patients with early and late-onset Alzheimer's disease (EOAD and LOAD) is still unclear, and this might due to the complex AD pathology. METHODS: We included 31 EOAD, 45 LOAD, and 64 younger, 46 elder controls in our study to undergo MRI examinations. Fiber density (FD) and fiber bundle cross-section (FC) were measured using fixel-based analysis based on diffusion weighted images. On whole brain and tract-based level, we compared these parameters among different groups (p<0.05, FWE corrected). Moreover, we verified our results in another independent dataset using the same analyses. RESULTS: Compared to young healthy controls, EOAD had significantly lower FD in the splenium of corpus callosum, limbic tracts, cingulum bundles, and posterior thalamic radiation, and higher FC in the splenium of corpus callosum, dorsal cingulum and posterior thalamic radiation. On the other hand, LOAD had lower FD and FC as well. Importantly, a similar pattern was found in the independent validation dataset. Among all groups, both the FD and FC were associated with cognitive function. Furthermore, FD of fornix column and body, and FC of ventral cingulum were associated with composite amyloid and tau level (r=-0.34 and -0.53, p<0.001) respectively. CONCLUSIONS: EOAD and LOAD were characterized by distinct white matter impairment patterns, which may be attributable to their different neuropathologies.


Assuntos
Doença de Alzheimer/patologia , Imagem de Difusão por Ressonância Magnética , Progressão da Doença , Placa Amiloide/patologia , Substância Branca/patologia , Idade de Início , Idoso , Encéfalo/patologia , Imagem de Difusão por Ressonância Magnética/métodos , Imagem de Tensor de Difusão/métodos , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade
9.
Int J Mol Sci ; 22(6)2021 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-33809300

RESUMO

Alzheimer's disease (AD), the most common form of neurodegenerative dementia in adults worldwide, is a multifactorial and heterogeneous disorder characterized by the interaction of genetic and epigenetic factors and the dysregulation of numerous intracellular signaling and cellular/molecular pathways. The introduction of the systems biology framework is revolutionizing the study of complex diseases by allowing the identification and integration of cellular/molecular pathways and networks of interaction. Here, we reviewed the relationship between physical activity and the next pathophysiological processes involved in the risk of developing AD, based on some crucial molecular pathways and biological process dysregulated in AD: (1) Immune system and inflammation; (2) Endothelial function and cerebrovascular insufficiency; (3) Apoptosis and cell death; (4) Intercellular communication; (5) Metabolism, oxidative stress and neurotoxicity; (6) DNA damage and repair; (7) Cytoskeleton and membrane proteins; (8) Synaptic plasticity. Moreover, we highlighted the increasingly relevant role played by advanced neuroimaging technologies, including structural/functional magnetic resonance imaging, diffusion tensor imaging, and arterial spin labelling, in exploring the link between AD and physical exercise. Regular physical exercise seems to have a protective effect against AD by inhibiting different pathophysiological molecular pathways implicated in AD.


Assuntos
Doença de Alzheimer/terapia , Exercício Físico/fisiologia , Estresse Oxidativo/fisiologia , Doença de Alzheimer/genética , Doença de Alzheimer/fisiopatologia , Doença de Alzheimer/reabilitação , Dano ao DNA/genética , Reparo do DNA/genética , Imagem de Tensor de Difusão/métodos , Humanos , Imageamento por Ressonância Magnética/métodos , Neuroimagem/métodos , Transdução de Sinais/genética
10.
Radiol Clin North Am ; 59(3): 335-347, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33926681

RESUMO

Diffusion MR imaging exploits the diffusion properties of water to generate contrast between normal tissue and pathology. Diffusion is an essential component of nearly all brain tumor MR imaging examinations. This review covers the important clinical applications of diffusion weighted imaging in the pretreatment diagnosis and grading of brain tumors and assessment of treatment response. Diffusion imaging improves the accuracy of identifying treatment-related effects that may mimic tumor improvement or worsening. Fiber tractography models of eloquent white matter pathways are generated using diffusion tensor imaging. A practical and concise tractography guide is provided for anyone new to preoperative surgical mapping.


Assuntos
Neoplasias Encefálicas/diagnóstico por imagem , Imagem de Difusão por Ressonância Magnética/métodos , Cuidados Pós-Operatórios/métodos , Cuidados Pré-Operatórios/métodos , Encéfalo/diagnóstico por imagem , Neoplasias Encefálicas/cirurgia , Imagem de Tensor de Difusão/métodos , Humanos
11.
AJNR Am J Neuroradiol ; 42(5): 875-881, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33664113

RESUMO

BACKGROUND AND PURPOSE: Whole-brain network connectivity has been shown to be a useful biomarker of cerebral amyloid angiopathy and related cognitive impairment. We evaluated an automated DTI-based method, peak width of skeletonized mean diffusivity, in cerebral amyloid angiopathy, together with its association with conventional MRI markers and cognitive functions. MATERIALS AND METHODS: We included 24 subjects (mean age, 74.7 [SD, 6.0] years) with probable cerebral amyloid angiopathy and mild cognitive impairment and 62 patients with MCI not attributable to cerebral amyloid angiopathy (non-cerebral amyloid angiopathy-mild cognitive impairment). We compared peak width of skeletonized mean diffusivity between subjects with cerebral amyloid angiopathy-mild cognitive impairment and non-cerebral amyloid angiopathy-mild cognitive impairment and explored its associations with cognitive functions and conventional markers of cerebral small-vessel disease, using linear regression models. RESULTS: Subjects with Cerebral amyloid angiopathy-mild cognitive impairment showed increased peak width of skeletonized mean diffusivity in comparison to those with non-cerebral amyloid angiopathy-mild cognitive impairment (P < .001). Peak width of skeletonized mean diffusivity values were correlated with the volume of white matter hyperintensities in both groups. Higher peak width of skeletonized mean diffusivity was associated with worse performance in processing speed among patients with cerebral amyloid angiopathy, after adjusting for other MRI markers of cerebral small vessel disease. The peak width of skeletonized mean diffusivity did not correlate with cognitive functions among those with non-cerebral amyloid angiopathy-mild cognitive impairment. CONCLUSIONS: Peak width of skeletonized mean diffusivity is altered in cerebral amyloid angiopathy and is associated with performance in processing speed. This DTI-based method may reflect the degree of white matter structural disruption in cerebral amyloid angiopathy and could be a useful biomarker for cognition in this population.


Assuntos
Angiopatia Amiloide Cerebral/diagnóstico por imagem , Imagem de Tensor de Difusão/métodos , Processamento de Imagem Assistida por Computador/métodos , Idoso , Idoso de 80 Anos ou mais , Biomarcadores , Angiopatia Amiloide Cerebral/psicologia , Doenças de Pequenos Vasos Cerebrais/diagnóstico por imagem , Cognição , Disfunção Cognitiva/diagnóstico por imagem , Disfunção Cognitiva/psicologia , Imagem de Difusão por Ressonância Magnética , Feminino , Humanos , Masculino , Neuroimagem , Desempenho Psicomotor , Tempo de Reação
12.
World Neurosurg ; 150: e520-e529, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33744423

RESUMO

BACKGROUND: The middle frontal gyrus (MFG) is involved in attention, working memory, and language-related processing. A detailed understanding of the subcortical white matter tracts connected within the MFG can facilitate improved navigation of white matter lesions in and around this gyrus and explain the postoperative morbidity after surgery. We aimed to characterize the fiber tracts within the MFG according to their connection to neuroanatomic structures through the use of diffusion spectrum imaging-based fiber tractography and validate the findings by gross anatomic dissection for qualitative visual agreement. METHODS: Tractography analysis was completed using diffusion imaging data from 10 healthy, adult subjects enrolled in the Human Connectome Project. We assessed the MFG as a whole component according to its fiber connectivity with other neural regions. Mapping was completed on all tracts within both hemispheres, with the resultant tract volumes used to calculate a lateralization index. A modified Klingler technique was used on 10 postmortem dissections to demonstrate the location and orientation of the major tracts. RESULTS: Two major connections of the MFG were identified: the superior longitudinal fasciculus, which connects the MFG to parts of the inferior parietal lobule, posterior temporal lobe, and lateral occipital cortex; and the inferior fronto-occipital fasciculus, which connected the MFG to the lingual gyrus and cuneus. Intra- and intergyral short association, U-shaped fibers were also identified. CONCLUSIONS: Subcortical white matter pathways integrated within the MFG include the superior longitudinal fasciculus and inferior fronto-occipital fasciculus. The MFG is implicated in a variety of tasks involving attention and memory, making it an important cortical region. The postoperative neurologic outcomes related to surgery in and around the MFG could be clarified in the context of the anatomy of the fiber bundles highlighted in the present study.


Assuntos
Vias Neurais/anatomia & histologia , Córtex Pré-Frontal/anatomia & histologia , Substância Branca/anatomia & histologia , Imagem de Tensor de Difusão/métodos , Humanos
13.
Acta Neurol Scand ; 143(6): 637-645, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33733467

RESUMO

OBJECTIVE: The aim of this study was to evaluate the feasibility of machine learning based on diffusion tensor imaging (DTI) measures to distinguish patients with focal epilepsy versus healthy controls and antiseizure medication (ASM) responsiveness. METHODS: This was a retrospective study performed at a tertiary hospital. We enrolled 456 patients with focal epilepsy, who underwent DTI and were taking ASMs. We enrolled 100 healthy subjects as a control. We obtained the conventional DTI measures and structural connectomic profiles from the DTI. RESULTS: The support vector machine (SVM) classifier based on the conventional DTI measures revealed an accuracy of 76.5% and an area under curve (AUC) of 0.604 (95% Confidence interval (CI), 0.506-0.695). Another SVM classifier combined with structural connectomic profiles demonstrated an accuracy of 82.8% and an AUC of 0.701 (95% CI, 0.606-0.784). Of the 456 patients with epilepsy, 242 patients were ASM good responders, whereas 214 patients were ASM poor responders. In the classification of the ASM responders, an SVM classifier based on the conventional DTI measures revealed an accuracy of 54.9% and an AUC of 0.551 (95% CI, 0.443-0.655). Another SVM classifier combined with structural connectomic profiles demonstrated an accuracy of 59.3% and an AUC of 0.594 (95% CI, 0.485-0.695). CONCLUSION: DTI using a machine learning is useful for differentiating patients with focal epilepsy from healthy controls, but it cannot classify ASM responsiveness. Combining structural connectomic profiles results in a better classification performance than the use of conventional DTI measures alone for identifying focal epilepsy and ASM responsiveness.


Assuntos
Imagem de Tensor de Difusão/métodos , Epilepsias Parciais/diagnóstico por imagem , Interpretação de Imagem Assistida por Computador/métodos , Máquina de Vetores de Suporte , Adulto , Anticonvulsivantes/uso terapêutico , Conectoma/métodos , Epilepsias Parciais/tratamento farmacológico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
14.
Clin Radiol ; 76(7): 532-539, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33736880

RESUMO

AIM: To investigate the performance of intravoxel incoherent motion (IVIM) and diffusion kurtosis imaging (DKI) in the identification of peritumoural infiltration of soft-tissue sarcoma (STS). MATERIALS AND METHODS: From July 2018 to January 2020, 34 STS patients who underwent 3-T magnetic resonance imaging (MRI), including IVIM and DKI, were reviewed. The standard apparent diffusion coefficient (ADC), true diffusion (D), pseudo-diffusion coefficient (D∗), perfusion fraction (f), mean kurtosis (MK), and mean diffusion (MD) of each lesion were analysed independently by two observers. An MRI-histopathology control method was used to ensure the correspondence of MRI sections with histopathological sections. Differences in STS with and without infiltration were evaluated. The area under the curve (AUC) was used to determine the best cut-off point for different parameters. Interobserver agreement was assessed using the intraclass correlation coefficient. RESULTS: Standard ADC, D, MK, and MD values reliably distinguished STS that had positive and negative infiltration. The MD value had the best diagnostic performance. Use of an MD cut-off value of 2.35 × 10-3 mm2/s to distinguish positive and negative infiltration had an AUC of 0.85, accuracy of 88.2%, sensitivity of 94.4%, and specificity of 81.3%. The two independent observers had nearly perfect agreement for all parameters. CONCLUSION: The standard ADC and D value of IVIM, and the MK and MD values of DKI reliably identify the presence of peritumoural infiltration of STS.


Assuntos
Imagem de Tensor de Difusão/métodos , Invasividade Neoplásica/diagnóstico por imagem , Sarcoma/diagnóstico por imagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Invasividade Neoplásica/patologia , Estudos Prospectivos , Sarcoma/patologia , Sensibilidade e Especificidade
15.
Cancer Imaging ; 21(1): 30, 2021 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-33726862

RESUMO

BACKGROUND: To probe the feasibility and reproducibility of diffusion kurtosis tensor imaging (DKTI) in renal cell carcinoma (RCC) and to apply DKTI in distinguishing the subtypes of RCC and the grades of clear cell RCC (CCRCC). METHODS: Thirty-eight patients with pathologically confirmed RCCs [CCRCC for 30 tumors, papillary RCC (PRCC) for 5 tumors and chromophobic RCC (CRCC) for 3 tumors] were involved in the study. Diffusion kurtosis tensor MR imaging were performed with 3 b-values (0, 500, 1000s/mm2) and 30 diffusion directions. The mean kurtosis (MK), axial kurtosis (Ka), radial kurtosis (Kr) values and mean diffusity (MD) for RCC and contralateral normal parenchyma were acquired. The inter-observer agreements of all DKTI metrics of contralateral renal cortex and medulla were evaluated using Bland-Altman plots. Statistical comparisons with DKTI metrics of 3 RCC subtypes and between low-grade (Furman grade I ~ II, 22 cases) and high-grade (Furman grade III ~ IV, 8 cases) CCRCC were performed with ANOVA test and Student t test separately. Receiver operating characteristic (ROC) curve analyses were used to compare the diagnostic efficacy of DKTI metrics for predicting nuclear grades of CCRCC. Correlations between DKTI metrics and nuclear grades were also evaluated with Spearman correlation analysis. RESULTS: Inter-observer measurements for each metric showed great reproducibility with excellent ICCs ranging from 0.81 to 0.87. There were significant differences between the DKTI metrics of RCCs and contralateral renal parenchyma, also among the subtypes of RCC. MK and Ka values of CRCC were significantly higher than those of CCRCC and PRCC. Statistical difference of the MK, Ka, Kr and MD values were also obtained between CCRCC with high- and low-grades. MK values were more effective for distinguishing between low- and high- grade CCRCC (area under the ROC curve: 0.949). A threshold value of 0.851 permitted distinction with high sensitivity (90.9%) and specificity (87.5%). CONCLUSION: Our preliminary results suggest a possible role of DKTI in differentiating CRCC from CCRCC and PRCC. MK, the principle DKTI metric might be a surrogate biomarker to predict nuclear grades of CCRCC. TRIAL REGISTRATION: ChiCTC, ChiCTR-DOD-17010833, Registered 10 March, 2017, retrospectively registered, http://www.chictr.org.cn/showproj.aspx?proj=17559 .


Assuntos
Carcinoma de Células Renais/diagnóstico por imagem , Imagem de Difusão por Ressonância Magnética/métodos , Imagem de Tensor de Difusão/métodos , Neoplasias Renais/diagnóstico por imagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma de Células Renais/patologia , Feminino , Humanos , Neoplasias Renais/patologia , Masculino , Pessoa de Meia-Idade , Gradação de Tumores
16.
Med Sci Monit ; 27: e929092, 2021 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-33707406

RESUMO

BACKGROUND The combined effects of bilateral corticospinal tract (CST) reorganization and interhemispheric functional connectivity (FC) reorganization on motor recovery of upper and lower limbs after stroke remain unknown. MATERIAL AND METHODS A total of 34 patients underwent magnetic resonance imaging (MRI) examination at weeks 1, 4, and 12 after stroke, with a control group of 34 healthy subjects receiving 1 MRI examination. Interhemispheric FC in the somatomotor network (SMN) was calculated using the resting-state functional MRI (rs-fMRI). Fractional anisotropy (FA) of bilateral CST was recorded as a measure of reorganization obtained from diffusion tensor imaging (DTI). After intergroup comparisons, multiple linear regression analysis was used to explore the effects of altered FA and interhemispheric FC on motor recovery. RESULTS Interhemispheric FC restoration mostly occurred within 4 weeks after stroke, and FA in ipsilesional remained CST consistently elevated within 12 weeks. Multivariate linear regression analysis showed that the increase in both interhemispheric FC and ipsilesional CST-FA were significantly correlated with greater motor recovery from week 1 to week 4 following stroke. Moreover, only increased FA of ipsilesional CST was significantly correlated with greater motor recovery during weeks 4 to 12 after stroke compared to interhemispheric FC. CONCLUSIONS Our results show dynamic structural and functional reorganizations following motor stroke, and structure reorganization may be more related to motor recovery at the late subacute phase. These results may play a role in guiding neurological rehabilitation.


Assuntos
Tratos Piramidais/diagnóstico por imagem , Tratos Piramidais/fisiologia , Recuperação de Função Fisiológica/fisiologia , Idoso , Anisotropia , China , Imagem de Tensor de Difusão/métodos , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Tratos Piramidais/patologia , Acidente Vascular Cerebral/fisiopatologia
17.
BMC Neurol ; 21(1): 128, 2021 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-33740898

RESUMO

BACKGROUND: Although increasing evidence showed the correlations between white matter hyperintensities (WMHs) and cognitive impairment, the relationship between them is still modest. Many researchers began to focus on the variation caused by the heterogeneity of WMH. We tried to explore the pathological heterogeneity in WMH by using diffusion tensor imaging (DTI), so as to provide a new insight into the future research. METHODS: Diffusion weighted images (DWIs) of the brain were acquired from 73 patients with WMH and 18 healthy controls, which were then modeled by DTI. We measured fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) of white matter of the periventricular frontal lobe (pFL), periventricular occipital lobe (pOL), periventricular parietal lobe (pPL) and deep centrum ovales (dCO), and grouped these measures according to the Fazekas scale. Then we compared the DTI metrics of different regions with the same Fazekas scale grade. RESULTS: Significantly lower FA values (all p < 0.001), and higher MD (all p < 0.001) and RD values (all p < 0.001) were associated with WMH observed in the periventricular frontal lobe (pFL) compared to all other regions with the same Fazekas grades. The AD of WMH in the pFL was higher than that of pPL and dCO, but the differences between groups was not as high as of MD and RD, as indicated by the effect size. In the normal control group, DTI metrics between pFL and other regions were not significantly different or less significant different. The difference of DTI metrics of WMH between pPL, pOL and dCO was lower than that of normal white matter, as indicated by the effect size. CONCLUSION: Distinct pathological processes can be revealed by DTI between frontal periventricular WMH and other regions. These processes may represent the effects of severe demyelination within the frontal periventricular WMH.


Assuntos
Encéfalo/patologia , Imagem de Tensor de Difusão/métodos , Substância Branca/patologia , Idoso , Idoso de 80 Anos ou mais , Anisotropia , Imagem de Difusão por Ressonância Magnética/métodos , Feminino , Humanos , Masculino
18.
J Clin Neurosci ; 86: 139-144, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33775318

RESUMO

We report the case of a patient who experienced recurrent ipsilateral hemiparesis in the setting of predominantly-uncrossed corticospinal tracts, with concomitant neuronal reorganization of the cortical motor maps, and the presence of aberrant interhemispheric connections. Their presence was supported by our results from diffusion tensor imaging tractography, functional magnetic resonance imaging, and transcranial magnetic stimulation. To our knowledge, this has never been reported before, and provides valuable insights into the mechanisms behind post-stroke motor recovery.


Assuntos
Córtex Motor/diagnóstico por imagem , Paresia/diagnóstico por imagem , Tratos Piramidais/diagnóstico por imagem , Acidente Vascular Cerebral/diagnóstico por imagem , Imagem de Tensor de Difusão/métodos , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Pessoa de Meia-Idade , Córtex Motor/fisiopatologia , Paresia/etiologia , Paresia/fisiopatologia , Tratos Piramidais/fisiopatologia , Recidiva , Acidente Vascular Cerebral/complicações , Acidente Vascular Cerebral/fisiopatologia
19.
J Clin Neurosci ; 86: 164-173, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33775321

RESUMO

Degenerative Cervical Myelopathy (DCM) is a spinal cord disorder that causes significant physical disabilities in older patients. While most DCM research focuses on the spinal cord, widespread reorganization of the brain may occur to compensate for functional impairment. This observational study used diffusion spectrum imaging (DSI) to examine reorganization of cerebral white matter associated with neurological impairment as measured by the modified Japanese Orthopedic Association (mJOA), and severity of neck disability as measured by the Neck Disability Index (NDI) score. A total of 47 patients were included in the cervical spondylosis (CS) cohort: 38 patients with DCM (mean mJOA = 14.6, and mean NDI = 12.0), and 9 neurologically asymptomatic patients with spinal cord compression (mJOA = 18, and mean NDI = 7.0). 28 healthy volunteers (HCs) served as the control group. Lower generalized fractional anisotropy (GFA) was observed throughout much of the brain in patients compared to HCs (p < 0.05). Fiber pathways associated with somatosensory functions, such as the corpus callosum and corona radiata, showed increased quantitative anisotropy (QA) in patients compared to HCs. Correlation analyses further suggested that structural connectivity was enhanced to compensate for neurological dysfunction within sensorimotor regions, where fibers such as the posterior corona radiata had NQA values that were negatively associated with mJOA (p = 0.0020, R2 = 0.2935) and positively associated with NDI score (p = 0.0164, R2 = 0.1889). Altogether, these results suggest that DCM and neurologically asymptomatic spinal cord compression patients tend to have long-term reorganization within the brain, particularly in those regions responsible for the perception and integration of sensory information, motor regulation, and pain modulation.


Assuntos
Encéfalo/diagnóstico por imagem , Vértebras Cervicais/diagnóstico por imagem , Imagem de Tensor de Difusão/métodos , Compressão da Medula Espinal/diagnóstico por imagem , Espondilose/diagnóstico por imagem , Substância Branca/diagnóstico por imagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Anisotropia , Encéfalo/fisiopatologia , Vértebras Cervicais/fisiopatologia , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Compressão da Medula Espinal/etiologia , Compressão da Medula Espinal/fisiopatologia , Doenças da Medula Espinal/complicações , Doenças da Medula Espinal/diagnóstico por imagem , Doenças da Medula Espinal/fisiopatologia , Espondilose/complicações , Espondilose/fisiopatologia , Substância Branca/fisiopatologia
20.
J Comput Assist Tomogr ; 45(2): 218-223, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33661149

RESUMO

ABSTRACT: Renal echo planar diffusion tensor imaging (DTI) has clinical potential but suffers from geometric distortion. We evaluated feasibility of reversed gradient distortion correction in 10 diabetic patients and 6 volunteers. Renal area, apparent diffusion coefficient, fractional anisotropy, and tensor eigenvalues were measured on uncorrected and distortion-corrected DTI. Corrected DTI correlated better than uncorrected DTI (r = 0.904 vs 0.840, P = 0.002) with reference anatomic T2-weighted imaging, with no significant difference in DTI metrics.


Assuntos
Imagem de Tensor de Difusão/métodos , Interpretação de Imagem Assistida por Computador/métodos , Rim/diagnóstico por imagem , Adulto , Nefropatias Diabéticas/diagnóstico por imagem , Estudos de Viabilidade , Humanos , Pessoa de Meia-Idade , Adulto Jovem
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