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1.
Cancer Imaging ; 21(1): 32, 2021 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-33827704

RESUMO

PURPOSE: To compare integrated slice-specific dynamic shimming (iShim) diffusion weighted imaging (DWI) and single-shot echo-planar imaging (SS-EPI) DWI in image quality and pathological characterization of rectal cancer. MATERIALS AND METHODS: A total of 193 consecutive rectal tumor patients were enrolled for retrospective analysis. Among them, 101 patients underwent iShim-DWI (b = 0, 800, and 1600 s/mm2) and 92 patients underwent SS-EPI-DWI (b = 0, and 1000 s/mm2). Qualitative analyses of both DWI techniques was performed by two independent readers; including adequate fat suppression, the presence of artifacts and image quality. Quantitative analysis was performed by calculating standard deviation (SD) of the gluteus maximus, signal intensity (SI) of lesion and residual normal rectal wall, apparent diffusion coefficient (ADC) values (generated by b values of 0, 800 and 1600 s/mm2 for iShim-DWI, and by b values of 0 and 1000 s/mm2 for SS-EPI-DWI) and image quality parameters, such as signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of primary rectal tumor. For the primary rectal cancer, two pathological groups were divided according to pathological results: Group 1 (well-differentiated) and Group 2 (poorly differentiated). Statistical analyses were performed with p < 0.05 as significant difference. RESULTS: Compared with SS-EPI-DWI, significantly higher scores of image quality were obtained in iShim-DWI cases (P < 0.001). The SDbackground was significantly reduced on b = 1600 s/mm2 images and ADC maps of iShim-DWI. Both SNR and CNR of b = 800 s/mm2 and b = 1600 s/mm2 images in iShim-DWI were higher than those of b = 1000 s/mm2 images in SS-EPI-DWI. In primary rectal cancer of iShim-DWI cohort, SIlesion was significantly higher than SIrectum in both b = 800 and 1600 s/mm2 images. ADC values were significantly lower in Group 2 (0.732 ± 0.08) × 10- 3 mm2/s) than those in Group 1 ((0.912 ± 0.21) × 10- 3 mm2/s). ROC analyses showed significance of ADC values and SIlesion between the two groups. CONCLUSION: iShim-DWI with b values of 0, 800 and 1600 s/mm2 is a promising technique of high image quality in rectal tumor imaging, and has potential ability to differentiate rectal cancer from normal wall and predicting pathological characterization.


Assuntos
Imagem de Difusão por Ressonância Magnética/métodos , Neoplasias Retais/diagnóstico por imagem , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
2.
Medicine (Baltimore) ; 100(17): e25751, 2021 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-33907171

RESUMO

ABSTRACT: Disrupted blood-brain barrier (BBB) in patients with ischemic stroke plays a critical role in malignant middle cerebral artery infarction (MMI) development.Cerebral white matter changes (WMC), particularly in the deep subcortical area or in severe one, may be also underlain by disrupted BBB. It is unclear whether the presence of WMC with potential premorbid disruption of BBB makes patients susceptible to MMI. Therefore, this study aimed to clarify any putative relationship between the MMI and WMC in terms of their severity and locations.In this case-control study, patients with infarction in the middle cerebral artery territory were retrospectively reviewed. Brain magnetic resonance images were analyzed according to Fazekas scale, and identified WMC were divided into periventricular WMC (PV-WMC) and deep subcortical WMC (deep-WMC). Patients were scored as having WMC, PV-WMC, deep-WMC, severe PV-WMC, and severe deep-WMC according to the severity and locations. Patients were defined as having MMI if either a progressive conscious disturbance or signs of uncal herniation was recorded in combination with a midline shift >5 mm identified on the follow-up computed tomography.Among 297 patients admitted between July 2009 and February 2015, 92 patients were eligible for final analysis. Compared to patients without MMI, patients with MMI had a higher score of National Institutes of Health Stroke Scale, a larger infarct volume, and an increasingly greater proportion of severe PV-WMC, deep-WMC, and severe deep-WMC, respectively. After adjustment for sex, age, infarct volume, and history of hypertension, severe deep-WMC (odds ratio [OR] = 6.362, 95% confidence interval [CI] = 1.444-28.023, P = .0144) and severe PV-WMC (odds ratio = 5.608, 95% confidence interval = 1.107-28.399, P = .0372) were significantly associated with MMI development.MMI and WMC are significantly associated such that MMI development is more likely when PV-WMC or deep-WMC is more severe. We hypothesize that Fazekas scale-defined severe deep-WMC and PV-WMC may be considered as clinically approachable predictors of MMI development. These findings support that the WMC with potential premorbid disrupted BBB may make patients susceptible to MMI, and further prospective study should be conducted to clarify this hypothesis.


Assuntos
Barreira Hematoencefálica/fisiopatologia , Infarto da Artéria Cerebral Média , Substância Branca , Idoso , Estudos de Casos e Controles , Correlação de Dados , Imagem de Difusão por Ressonância Magnética/métodos , Suscetibilidade a Doenças , Feminino , Humanos , Infarto da Artéria Cerebral Média/diagnóstico , Infarto da Artéria Cerebral Média/epidemiologia , Infarto da Artéria Cerebral Média/fisiopatologia , /patologia , Masculino , Índice de Gravidade de Doença , Taiwan/epidemiologia , Tomografia Computadorizada por Raios X/métodos , Substância Branca/diagnóstico por imagem , Substância Branca/patologia , Substância Branca/fisiopatologia
3.
Cancer Imaging ; 21(1): 34, 2021 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-33849649

RESUMO

BACKGROUND: The extent of peritoneal carcinomatosis is difficult to estimate preoperatively, but a valid measure would be important in identifying operable patients. The present study set out to validate the usefulness of integrated 18F-FDG PET/MRI, in comparison with diffusion-weighted MRI (DW-MRI), for estimation of the extent of peritoneal carcinomatosis in patients with gynaecological cancer. METHODS: Whole-body PET/MRI was performed on 34 patients with presumed carcinomatosis of gynaecological origin, all scheduled for surgery. Two radiologists evaluated the peritoneal cancer index (PCI) on PET/MRI and DW-MRI scans in consensus. The surgeon estimated PCI intraoperatively, which was used as the gold standard. RESULTS: Median total PCI for PET/MRI (21.5) was closer to surgical PCI (24.5) (p = 0.6), than DW-MRI (median PCI 20.0, p = 0.007). However, both methods were highly correlated with the surgical PCI (PET/MRI: ß = 0.94 p < 0.01, DW-MRI: ß = 0.86, p < 0.01). PET/MRI was more accurate (p = 0.3) than DW-MRI (p = 0.001) when evaluating patients at primary diagnosis but no difference was noted in patients treated with chemotherapy. PET/MRI was superior in evaluating high tumour burden in inoperable patients. In the small bowel regions, there was a tendency of higher sensitivity but lower specificity in PET/MRI compared to DW-MRI. CONCLUSIONS: Our results suggest that FDG PET/MRI is superior to DW-MRI in estimating total spread of carcinomatosis in gynaecological cancer. Further, the greatest advantage of PET/MRI seems to be in patients at primary diagnosis and with high tumour burden, which suggest that it could be a useful tool when deciding about operability in gynaecological cancer.


Assuntos
Carcinoma/diagnóstico por imagem , Imagem de Difusão por Ressonância Magnética/métodos , Neoplasias do Endométrio/diagnóstico por imagem , Fluordesoxiglucose F18/metabolismo , Neoplasias Ovarianas/diagnóstico por imagem , Neoplasias Peritoneais/diagnóstico por imagem , Tomografia por Emissão de Pósitrons/métodos , Tomografia Computadorizada por Raios X/métodos , Adulto , Idoso , Neoplasias do Endométrio/mortalidade , Neoplasias do Endométrio/patologia , Feminino , Humanos , Pessoa de Meia-Idade , Neoplasias Ovarianas/mortalidade , Neoplasias Ovarianas/patologia , Neoplasias Peritoneais/mortalidade , Neoplasias Peritoneais/patologia , Projetos Piloto , Reprodutibilidade dos Testes , Análise de Sobrevida
4.
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
5.
Anticancer Res ; 41(3): 1163-1170, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33788707

RESUMO

BACKGROUND/AIM: Magnetic resonance imaging is used for staging purposes in cervical cancer (CC). Diffusion-weighted imaging and the apparent diffusion coefficient (ADC) are associated with tumor microstructure. The present analysis sought to compare pre-treatment ADC values to predict treatment outcome of radiochemotherapy for CC based upon a large patient sample. MATERIALS AND METHODS: MEDLINE library and SCOPUS databases were assessed for suitable articles up to May 2020. The primary endpoint was the mean ADC value of CC according to the treatment response to radiochemotherapy. In total, 16 studies were included in the analysis. RESULTS: For the response group, 416 patients were included in the analysis (72.5%) and for the no-response group 158 patients were included (27.5%). The mean ADC value of patients with CC with treatment response was 0.87×10-3 mm2/s (95% confidence interval=0.81-0.94×10-3 mm2/s), and for the patients with no response was 0.92×10-3 mm2/s (95% confidence interval=0.85-0.98×10-3 mm2/s). CONCLUSION: Pre-treatment ADC values alone cannot be used to reliably predict treatment response to radiochemotherapy in CC.


Assuntos
Quimiorradioterapia , Imagem de Difusão por Ressonância Magnética/métodos , Neoplasias do Colo do Útero/terapia , Difusão , Feminino , Humanos , Neoplasias do Colo do Útero/diagnóstico por imagem
6.
AJR Am J Roentgenol ; 216(5): 1240-1246, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33760653

RESUMO

OBJECTIVE. The purpose of this article was to evaluate the DWI features of autoimmune pancreatitis (AIP) at baseline, under treatment, and at relapse, and to assess the diagnostic accuracy of the ADC for determining disease activity. MATERIALS AND METHODS. This retrospective study was approved by the institutional review board. Sixty-two patients with AIP (48 at initial attack and 14 at relapse) underwent MRI with DWI (b = 0 and 800 s/mm2) at 3 T before receiving corticosteroid therapy (CST) and during follow-up. Seventeen patients had disease relapse during follow-up, whereas the others remained clinically stable. Forty age- and sex-matched patients without pancreatic disease served as the control group. RESULTS. The ADC value of AIP at baseline was significantly lower than that for a disease-free pancreas (0.99 ± 0.12 vs 1.26 ± 0.10 × 10-3 mm2/s, p < .001). Under CST, the ADC value increased gradually at the short-term and long-term follow-up (1.16 ± 0.12 and 1.23 ± 0.12 × 10-3 mm2/s, respectively, both p < .001). At relapse, the ADC had a relative decrease (1.11 ± 0.20 × 10-3 mm2/s) but was significantly higher compared with the initial attack (p = .003). The AUC of ADC serum IgG4 level at ROC analysis for baseline versus clinically stable AIP was 0.867 and 0.700, the AUC for clinically active AIP versus clinically stable AIP was 0.762 and 0.686, and the AUC for relapsed AIP versus clinically stable AIP was 0.648 and 0.669. CONCLUSION. DWI reflected the dynamic change of AIP under CST, and the ADC value for DWI outperformed the serum IgG4 value for determining disease activity. However, relapsed disease showed less diffusion restriction, and the ADC value was less accurate for predicting relapse.


Assuntos
Pancreatite Autoimune/diagnóstico por imagem , Pancreatite Autoimune/patologia , Imagem de Difusão por Ressonância Magnética/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores , Diagnóstico Diferencial , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pâncreas/diagnóstico por imagem , Pâncreas/patologia , Recidiva , Reprodutibilidade dos Testes , Estudos Retrospectivos
7.
Neurology ; 96(17): e2192-e2200, 2021 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-33762423

RESUMO

OBJECTIVE: To investigate the 2-year change in parenchymal diffusivity, a quantitative marker of microstructural tissue condition, and the relationship with baseline blood-brain barrier (BBB) permeability, in tissue at risk, i.e., the perilesional zone surrounding white matter hyperintensities (WMH) in patients with cerebral small vessel disease (cSVD). METHODS: Patients with sporadic cSVD (lacunar stroke or mild vascular cognitive impairment) underwent 3T MRI at baseline, including dynamic contrast-enhanced MRI to quantify BBB permeability (i.e., leakage volume and rate) and intravoxel incoherent motion imaging (IVIM), a diffusion technique that provides parenchymal diffusivity D. After 2 years, IVIM was repeated. We assessed the relation between BBB leakage measures at baseline and change in parenchymal diffusivity (∆D) over 2 years in the perilesional zones (divided in 2-mm contours) surrounding WMH. RESULTS: We analyzed 43 patients (age 68 ± 12 years, 58% male). In the perilesional zones, ∆D increased 0.10% (confidence interval [CI] 0.07-0.013%) (p < 0.01) per 2 mm closer to the WMH. Furthermore, ∆D over 2 years showed a positive correlation with both baseline BBB leakage volume (r = 0.29 [CI 0.06-0.52], p = 0.013) and leakage rate (r = 0.24 [CI 0.02-0.47], p = 0.034). CONCLUSION: BBB leakage at baseline is related to the 2-year change in parenchymal diffusivity in the perilesional zone of WMH. These results support the hypothesis that BBB impairment might play an early role in subsequent microstructural white matter degeneration as part of the pathophysiology of cSVD.


Assuntos
Barreira Hematoencefálica/patologia , Barreira Hematoencefálica/fisiopatologia , Doenças de Pequenos Vasos Cerebrais/fisiopatologia , Substância Branca/fisiopatologia , Idoso , Idoso de 80 Anos ou mais , Disfunção Cognitiva/fisiopatologia , Imagem de Difusão por Ressonância Magnética/métodos , Feminino , Substância Cinzenta/fisiopatologia , Humanos , Leucoaraiose/fisiopatologia , Masculino , Pessoa de Meia-Idade
8.
Br J Radiol ; 94(1121): 20210005, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33684304

RESUMO

OBJECTIVES: To explore the potential value of multiparametric magnetic resonance imaging (mpMRI) texture analysis (TA) to predict new Gleason Grade Group (GGG). METHODS: Fifty-eight lesions of fifty patients who underwent mpMRI scanning, including T2-weighted imaging (T2WI) and diffusion-weighted imaging (DWI) prior to trans-rectal ultrasound (TRUS)-guided core prostate biopsy, were retrospectively enrolled. TA parameters were obtained by the postprocessing software, and each lesion was assigned to its corresponding GGG. TA parameters derived from T2WI and DWI were statistically analyzed in detail. RESULTS: Energy, inertia, and correlation derived from apparent diffusion coefficient (ADC) maps and T2WI had a statistically significant difference among the five groups. Kurtosis, energy, inertia, correlation on ADC maps and Energy, inertia on T2WI were moderately related to the GGG trend. ADC-energy and T2-energy were significant independent predictors of the GGG trend. ADC-energy, T2WI-energy, and T2WI-correlation had a statistically significant difference between GGG1 and GGG2-5. ADC-energy were significant independent predictors of the GGG1. ADC-energy, T2WI-energy, and T2WI-correlation showed satisfactory diagnostic efficiency of GGG1 (area under the curve (AUC) 84.6, 74.3, and 83.5%, respectively), and ADC-energy showed excellent sensitivity and specificity (88.9 and 95.1%, respectively). CONCLUSION: TA parameters ADC-energy and T2-energy played an important role in predicting GGG trend. Both ADC-energy and T2-correlation produced a high diagnostic power of GGG1, and ADC-energy was perfect predictors of GGG1. ADVANCES IN KNOWLEDGE: TA parameters were innovatively used to predict new GGG trend, and the predictive factors of GGG1 were screen out.


Assuntos
Imagem por Ressonância Magnética/métodos , Gradação de Tumores/métodos , Neoplasias da Próstata/diagnóstico por imagem , Neoplasias da Próstata/patologia , Biópsia , Imagem de Difusão por Ressonância Magnética/métodos , Humanos , Masculino , Próstata/patologia , Curva ROC , Estudos Retrospectivos , Software , Estatísticas não Paramétricas , Ultrassonografia de Intervenção/métodos
9.
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
10.
Magn Reson Imaging ; 78: 18-24, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33556484

RESUMO

BACKGROUND: To evaluate 3-dimensional amide proton transfer weighted (APTw) imaging for type I endometrial carcinoma (EC), and investigate correlations of Ki-67 labelling index with APTw and intravoxel incoherent motion (IVIM) imaging. METHODS: 54 consecutive patients suspected of endometrial lesions underwent pelvic APTw and IVIM imaging on a 3 T MR scanner. APTw values and IVIM-derived parameters (Dt, D*, f) were independently measured by two radiologists on 22 postoperative pathological confirmed of type I EC lesions. Results were compared between histological grades and Ki-67 proliferation groups. ROC analysis was performed. Pearson's correlation analysis was performed for APTw values and IVIM-derived parameters with Ki-67 labeling index. RESULTS: APTw values and Dt, D*, f of all type I EC were 2.9 ± 0.1%, 0.677 ± 0.027 × 10-3 mm2/s, 31.801 ± 11.492 × 10-3 mm2/s, 0.179 ± 0.050 with inter-observer ICC 0.996, 0.850, 0.956, 0.995, respectively. APTw values of Ki-67 low-proliferation group (<30%, n = 8) were 2.5 ± 0.2%, significantly lower than the high-proliferation group (>30%, n = 14) with APTw values of 3.1 ± 0.1% (p = 0.016). Area under the curve was 0.768. APTw values of type I EC were moderately positively correlated with Ki-67 labelling index (r = 0.583, p = 0.004). There was no significant difference of Dt (p = 0.843), D* (p = 0.262), f (p = 0.553) between the two groups. No correlation was found between IVIM-derived parameters and Ki-67 labelling index (Dt, p = 0.717; D* p = 0.151; f, p = 0.153). CONCLUSION: 3D TSE APTw imaging is a feasible approach for detecting type I EC. Ki-67 labeling index positively moderately correlates with APTw not with IVIM.


Assuntos
Amidas/química , Imagem de Difusão por Ressonância Magnética/métodos , Neoplasias do Endométrio/diagnóstico por imagem , Neoplasias do Endométrio/patologia , Imageamento Tridimensional/métodos , Antígeno Ki-67/metabolismo , Prótons , Adulto , Idoso , Proliferação de Células , Neoplasias do Endométrio/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Curva ROC
11.
Br J Radiol ; 94(1121): 20200869, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33596102

RESUMO

OBJECTIVES: Diffusion-weighted imaging (DWI) plays a crucial role in the diagnosis of ischemic stroke. We assessed the value of computed and acquired high b-value DWI in comparison with conventional b = 1000 s mm-2 DWI for ischemic stroke at 3T. METHODS: We included 36 patients with acute ischemic stroke who presented with diffusion abnormalities on DWI performed within 24 h of symptom onset. B-values of 0, 500, 1000 and 2000 s mm-2 were acquired. Synthetic images with b-values of 1000, 1500, 2000 and 2500 s mm-2 were computed. Two readers compared synthetic (syn) and acquired (acq) b = 2000 s mm-2 images with acquired b = 1000 s mm-2 images in terms of lesion detection rate, image quality, presence of uncertain hyperintensities and lesion conspicuity. Readers also selected their preferred b-value. Contrast ratio (CR) measurements were performed. Non-parametrical statistical tests and weighted Cohens' κ tests were computed. RESULTS: Syn1000 and syn1500 matched acq1000 images in terms of lesion detection rate, image quality and presence of uncertain hyperintensities but presented with significantly improved lesion conspicuity (p < 0.01) and were frequently selected as preferred b-values. Acq2000 images exhibited a similar lesion detection rate and improved lesion conspicuity (p < 0.01) but worse image quality (p < 0.01) than acq1000 images. Syn2000 and syn2500 images performed significantly worse (p < 0.01) than acq1000 images in most or all categories. CR significantly increased with increasing b-values. CONCLUSION: Synthetic images at b = 1000 and 1500 s mm-2 and acquired DWI images at b = 2000 s mm-2 may be of clinical value due to improved lesion conspicuity. ADVANCES IN KNOWLEDGE: Synthetic b-values enable improved lesion conspicuity for DWI of ischemic stroke.


Assuntos
Imagem de Difusão por Ressonância Magnética/métodos , /diagnóstico por imagem , Idoso , Idoso de 80 Anos ou mais , Imagem de Difusão por Ressonância Magnética/normas , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Padrões de Referência , Estudos Retrospectivos , Razão Sinal-Ruído , Incerteza
12.
Medicine (Baltimore) ; 100(6): e24646, 2021 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-33578590

RESUMO

ABSTRACT: MR tractography of the lumbosacral plexus (LSP) is challenging due to the difficulty of acquiring high quality data and accurately estimating the neuronal tracts. We proposed an algorithm for an accurate visualization and assessment of the major LSP bundles using the segmentation of the cauda equina as seed points for the initial starting area for the fiber tracking algorithm.Twenty-six healthy volunteers underwent MRI examinations on a 3T MR scanner using the phased array coils with optimized measurement protocols for diffusion-weighted images and coronal T2 weighted 3D short-term inversion recovery sampling perfection with application optimized contrast using varying flip angle evaluation sequences used for LSP fiber reconstruction and MR neurography (MRN).The fiber bundles reconstruction was optimized in terms of eliminating the muscle fibers contamination using the segmentation of cauda equina, the effects of the normalized quantitative anisotropy (NQA) and angular threshold on reconstruction of the LSP. In this study, the NQA parameter has been used for fiber tracking instead of fractional anisotropy (FA) and the regions of interest positioning was precisely adjusted bilaterally and symmetrically in each individual subject.The diffusion data were processed in individual L3-S2 nerve fibers using the generalized Q-sampling imaging algorithm. Data (mean FA, mean diffusivity, axial diffusivity and radial diffusivity, and normalized quantitative anisotropy) were statistically analyzed using the linear mixed-effects model. The MR neurography was performed in MedINRIA and post-processed using the maximum intensity projection method to demonstrate LSP tracts in multiple planes.FA values significantly decreased towards the sacral region (P < .001); by contrast, mean diffusivity, axial diffusivity, radial diffusivity and NQA values significantly increased towards the sacral region (P < .001).Fiber tractography of the LSP was feasible in all examined subjects and closely corresponded with the nerves visible in the maximum intensity projection images of MR neurography. Usage of NQA instead of FA in the proposed algorithm enabled better separation of muscle and nerve fibers.The presented algorithm yields a high quality reconstruction of the LSP bundles that may be helpful both in research and clinical practice.


Assuntos
Imagem de Difusão por Ressonância Magnética/métodos , Imagem de Tensor de Difusão/métodos , Plexo Lombossacral/diagnóstico por imagem , Imagem por Ressonância Magnética/métodos , Nervos Espinhais/diagnóstico por imagem , Adulto , Algoritmos , Anisotropia , Cauda Equina/diagnóstico por imagem , Feminino , Humanos , Processamento de Imagem Assistida por Computador/métodos , Imageamento Tridimensional/instrumentação , Região Lombossacral/inervação , Masculino , Nervos Espinhais/anatomia & histologia
13.
Medicine (Baltimore) ; 100(5): e24251, 2021 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-33592867

RESUMO

BACKGROUND: Previous meta-analyses examined either multiple tools for the diagnosis of peritoneal metastases (PMs), but not diffusion-weighted imaging (DWI), or included only 1 tumor type. This study aimed to determine the summary diagnostic value of DWI/magnetic resonance imaging in determining PMs originating from various tumors. METHODS: PubMed, Embase, and Cochrane library were searched for available papers up to 2019/12. Pooled estimates for sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and accuracy were calculated using random-effects models. RESULTS: Ten studies were included and could be used to calculate the pooled sensitivity and specificity. The pooled sensitivity of DWI for PMs was 89% (95% confidence interval [CI]: 83%-93%). The pooled specificity was 86% (95% CI: 79%-91%). When considering only the retrospective studies, the pooled sensitivity of DWI for PMs was 85% (95% CI: 81%-89%). The pooled specificity was 84% (95% CI: 72%-92%). When considering only the studies about gastrointestinal tumors, the pooled sensitivity of DWI for PMs was 97% (95% CI: 68%-100%). The pooled specificity was 86% (95% CI: 69%-95%). No publication bias was observed (P = dd.27). CONCLUSION: DWI magnetic resonance imaging is highly sensitive and specific for the detection of PMs from various abdominal cancers.


Assuntos
Imagem de Difusão por Ressonância Magnética/métodos , Metástase Neoplásica/diagnóstico , Neoplasias/patologia , Neoplasias Peritoneais , Humanos , Neoplasias Peritoneais/diagnóstico por imagem , Neoplasias Peritoneais/secundário , Sensibilidade e Especificidade
14.
Br J Radiol ; 94(1119): 20200624, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33411594

RESUMO

OBJECTIVES: Diffusion-weighted imaging signal contrast can be quantified by apparent diffusion coefficient (ADC) maps, which reflect the diffusion properties of the examined tissue and are helpful for identifying pathology. To determine ADC values of cryptorchid testes in post-pubertal patients and assess performance for characterizing cryptorchid testes. METHODS: The medical records from 35 patients with unilateral scrotal vacuity were retrospectively reviewed. Data were analyzed in three groups: Group A, normal testes (i.e. the contralateral testes of the patients with cryptorchidism or MTC); Group B, cryptorchid testes; and Group C, malignant transformation of cryptorchidism (MTC) (seminoma). DWI used b-values of 0 and 800 s/mm2. Mean ADC values were compared using the independent samples t-test. The ability of ADC values was assessed using receiver operating characteristic curve analysis. The sensitivity, specificity, and accuracy were calculated. RESULTS: Mean ADC values for normal testes, cryptorchid testes, and MTC were 1.18 ± 0.18×10-3 mm2/s, 1.82 ± 0.40×10-3 mm2/s, and 0.80 ± 0.06×10-3 mm2/s, respectively. There were statistically significant differences in mean ADC values between normal testes and cryptorchid testes or MTC (p < 0.001). The cut-off ADC value for differentiating normal testes from cryptorchid testes was 1.47 × 10-3 mm2/s. The sensitivity, specificity, and accuracy were 88%, 91%, and 90%, respectively. The cut-off ADC value for differentiating normal testes from MTC was 1.22 × 10-3 mm2/s. The sensitivity, specificity, and accuracy were 100%, 31%, and 43%, respectively. CONCLUSION: ADC values of cryptorchid testes may be used to inform clinical decision-making and also monitor testicular function in patients who retain undescended testicles or post-operatively. ADVANCES IN KNOWLEDGE: Mean ADC values of cryptorchidism and MTC (seminoma) were used to reflect their pathological features.


Assuntos
Criptorquidismo/diagnóstico por imagem , Imagem de Difusão por Ressonância Magnética/métodos , Seminoma/diagnóstico por imagem , Neoplasias Testiculares/diagnóstico por imagem , Adulto , Criptorquidismo/complicações , Progressão da Doença , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Seminoma/complicações , Sensibilidade e Especificidade , Neoplasias Testiculares/complicações , Testículo/diagnóstico por imagem , Adulto Jovem
15.
Cancer Imaging ; 21(1): 12, 2021 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-33446273

RESUMO

BACKGROUND: To compare different fitting methods for determining IVIM (Intravoxel Incoherent Motion) parameters and to determine whether the use of different IVIM fitting methods would affect differentiation of cervix cancer from normal cervix tissue. METHODS: Diffusion-weighted echo-planar imaging of 30 subjects was performed on a 3.0 T scanner with b-values of 0, 30, 100, 200, 400, 1000 s/mm2. IVIM parameters were estimated using the segmented (two-step) fitting method and by simultaneous fitting of a bi-exponential function. Segmented fitting was performed using two different cut-off b-values (100 and 200 s/mm2) to study possible variations due to the choice of cut-off. Friedman's test and Student's t-test were respectively used to compare IVIM parameters derived from different methods, and between cancer and normal tissues. RESULTS: No significant difference was found between IVIM parameters derived from the segmented method with b-value cutoff of 200 s/mm2 and the simultaneous fitting method (P>0.05). Tissue diffusivity (D) and perfusion fraction (f) were significantly lower in cervix cancer than normal tissue (P< 0.05). CONCLUSIONS: IVIM parameters derived using fitting methods with small cutoff b-values could be different, however, the segmented method with b-value cutoff of 200 s/mm2 are consistent with the simultaneous fitting method and both can be used to differentiate between cervix cancer and normal tissue.


Assuntos
Imagem de Difusão por Ressonância Magnética/métodos , Imagem Ecoplanar/métodos , Neoplasias do Colo do Útero/diagnóstico por imagem , Feminino , Humanos , Pessoa de Meia-Idade , Movimento (Física) , Neoplasias do Colo do Útero/patologia
16.
Cancer Imaging ; 21(1): 13, 2021 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-33468259

RESUMO

BACKGROUND/OBJECTIVES: The aim of this study was to compare intravoxel incoherent motion (IVIM) diffusion weighted (DW) MRI and CT perfusion to assess tumor perfusion of pancreatic ductal adenocarcinoma (PDAC). METHODS: In this prospective study, DW-MRI and CT perfusion were conducted in nineteen patients with PDAC on the day before surgery. IVIM analysis of DW-MRI was performed and the parameters perfusion fraction f, pseudodiffusion coefficient D*, and diffusion coefficient D were extracted for tumors, upstream, and downstream parenchyma. With a deconvolution-based analysis, the CT perfusion parameters blood flow (BF) and blood volume (BV) were estimated for tumors, upstream, and downstream parenchyma. In ten patients, intratumoral microvessel density (MVDtumor) and microvessel area (MVAtumor) were analyzed microscopically in resection specimens. Correlation coefficients between IVIM parameters, CT perfusion parameters, and histological microvessel parameters in tumors were calculated. Receiver operating characteristic (ROC) analysis was performed for differentiation of tumors and upstream parenchyma. RESULTS: ftumor significantly positively correlated with BFtumor (r = 0.668, p = 0.002) and BVtumor (r = 0.672, p = 0.002). There were significant positive correlations between ftumor and MVDtumor/ MVAtumor (r ≥ 0.770, p ≤ 0.009) as well as between BFtumor and MVDtumor/ MVAtumor (r ≥ 0.697, p ≤ 0.025). Correlation coefficients between ftumor and MVDtumor/ MVAtumor were not significantly different from correlation coefficients between BFtumor and MVDtumor/ MVAtumor (p ≥ 0.400). Moreover, f, BF, BV, and permeability values (PEM) showed excellent performance in distinguishing tumors from upstream parenchyma (area under the ROC curve ≥0.874). CONCLUSIONS: The study shows that IVIM derived ftumor and CT perfusion derived BFtumor similarly reflect vascularity of PDAC and seem to be comparably applicable for the evaluation of tumor perfusion for tumor characterization and as potential quantitative imaging biomarker. TRIAL REGISTRATION: DRKS, DRKS00022227, Registered 26 June 2020, retrospectively registered. https://www.drks.de/drks_web/navigate.do?navigationId=trial . HTML&TRIAL_ID=DRKS00022227.


Assuntos
Adenocarcinoma/diagnóstico por imagem , Carcinoma Ductal Pancreático/diagnóstico por imagem , Imagem por Ressonância Magnética/métodos , Tomografia Computadorizada por Raios X/métodos , Imagem de Difusão por Ressonância Magnética/métodos , Feminino , Humanos , Masculino , Movimento (Física) , Perfusão , Estudos Prospectivos
17.
Cancer Imaging ; 21(1): 15, 2021 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-33478592

RESUMO

BACKGROUND: Computed tomography (CT) is the standard procedure for follow-up of non-small-cell lung cancer (NSCLC) after radiochemotherapy. CT has difficulties differentiating between tumor, atelectasis and radiation induced lung toxicity (RILT). Diffusion-weighted imaging (DWI) may enable a more accurate detection of vital tumor tissue. The aim of this study was to determine the diagnostic value of MRI versus CT in the follow-up of NSCLC. METHODS: Twelve patients with NSCLC stages I-III scheduled for radiochemotherapy were enrolled in this prospective study. CT with i.v. contrast agent and non enhanced MRI were performed before and 3, 6 and 12 months after treatment. Standardized ROIs were used to determine the apparent diffusion weighted coefficient (ADC) within the tumor. Tumor size was assessed by the longest longitudinal diameter (LD) and tumor volume on DWI and CT. RILT was assessed on a 4-point-score in breath-triggered T2-TSE and CT. RESULTS: There was no significant difference regarding LD and tumor volume between MRI and CT (p ≥ 0.6221, respectively p ≥ 0.25). Evaluation of RILT showed a very high correlation between MRI and CT at 3 (r = 0.8750) and 12 months (r = 0.903). Assessment of the ADC values suggested that patients with a good tumor response have higher ADC values than non-responders. CONCLUSIONS: DWI is equivalent to CT for tumor volume determination in patients with NSCLC during follow up. The extent of RILT can be reliably determined by MRI. DWI could become a beneficial method to assess tumor response more accurately. ADC values may be useful as a prognostic marker.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/diagnóstico por imagem , Carcinoma Pulmonar de Células não Pequenas/radioterapia , Imagem de Difusão por Ressonância Magnética/métodos , Neoplasias Pulmonares/diagnóstico por imagem , Neoplasias Pulmonares/radioterapia , Adulto , Idoso , Carcinoma Pulmonar de Células não Pequenas/patologia , Feminino , Humanos , Neoplasias Pulmonares/patologia , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Carga Tumoral
18.
Methods Mol Biol ; 2216: 187-204, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33476001

RESUMO

The specialized function of the kidney is reflected in its unique structure, characterized by juxtaposition of disorganized and ordered elements, including renal glomerula, capillaries, and tubules. The key role of the kidney in blood filtration, and changes in filtration rate and blood flow associated with pathological conditions, make it possible to investigate kidney function using the motion of water molecules in renal tissue. Diffusion-weighted imaging (DWI) is a versatile modality that sensitizes observable signal to water motion, and can inform on the complexity of the tissue microstructure. Several DWI acquisition strategies are available, as are different analysis strategies, and models that attempt to capture not only simple diffusion effects, but also perfusion, compartmentalization, and anisotropy. This chapter introduces the basic concepts of DWI alongside common acquisition schemes and models, and gives an overview of specific DWI applications for animal models of renal disease.This chapter is based upon work from the COST Action PARENCHIMA, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers. This introduction chapter is complemented by two separate chapters describing the experimental procedure and data analysis.


Assuntos
Biomarcadores/análise , Imagem de Difusão por Ressonância Magnética/métodos , Imagem de Tensor de Difusão/métodos , Aumento da Imagem/métodos , Processamento de Imagem Assistida por Computador/métodos , Rim/fisiologia , Monitorização Fisiológica/métodos , Animais , Humanos , Software
19.
Methods Mol Biol ; 2216: 205-227, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33476002

RESUMO

Dynamic contrast-enhanced (DCE) MRI monitors the transit of contrast agents, typically gadolinium chelates, through the intrarenal regions, the renal cortex, the medulla, and the collecting system. In this way, DCE-MRI reveals the renal uptake and excretion of the contrast agent. An optimal DCE-MRI acquisition protocol involves finding a good compromise between whole-kidney coverage (i.e., 3D imaging), spatial and temporal resolution, and contrast resolution. By analyzing the enhancement of the renal tissues as a function of time, one can determine indirect measures of clinically important single-kidney parameters as the renal blood flow, glomerular filtration rate, and intrarenal blood volumes. Gadolinium-containing contrast agents may be nephrotoxic in patients suffering from severe renal dysfunction, but otherwise DCE-MRI is clearly useful for diagnosis of renal functions and for assessing treatment response and posttransplant rejection.Here we introduce the concept of renal DCE-MRI, describe the existing methods, and provide an overview of preclinical DCE-MRI applications to illustrate the utility of this technique to measure renal perfusion and glomerular filtration rate in animal models.This publication is based upon work from the COST Action PARENCHIMA, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers. This introduction is complemented by two separate publications describing the experimental procedure and data analysis.


Assuntos
Biomarcadores/análise , Meios de Contraste/química , Imagem de Difusão por Ressonância Magnética/métodos , Taxa de Filtração Glomerular , Aumento da Imagem/métodos , Processamento de Imagem Assistida por Computador/métodos , Rim/fisiologia , Animais , Humanos , Monitorização Fisiológica/métodos , Perfusão , Circulação Renal , Software
20.
Methods Mol Biol ; 2216: 229-239, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33476003

RESUMO

The kidney is a complex organ involved in the excretion of metabolic products as well as the regulation of body fluids, osmolarity, and homeostatic status. These functions are influenced in large part by alterations in the regional distribution of blood flow between the renal cortex and medulla. Renal perfusion is therefore a key determinant of glomerular filtration. Therefore the quantification of regional renal perfusion could provide important insights into renal function and renal (patho)physiology. Arterial spin labeling (ASL) based perfusion MRI techniques, can offer a noninvasive and reproducible way of measuring renal perfusion in animal models. This chapter addresses the basic concept of ASL-MRI.This chapter is based upon work from the COST Action PARENCHIMA, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers. This introduction chapter is complemented by two separate chapters describing the experimental procedure and data analysis.


Assuntos
Biomarcadores/análise , Meios de Contraste/química , Imagem de Difusão por Ressonância Magnética/métodos , Processamento de Imagem Assistida por Computador/métodos , Rim/fisiologia , Circulação Renal , Marcadores de Spin , Animais , Artérias , Velocidade do Fluxo Sanguíneo , Humanos , Aumento da Imagem/métodos , Rim/irrigação sanguínea , Monitorização Fisiológica/métodos , Perfusão , Software
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