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Objective To evaluate the clinical manifestations, metal metabolism, imaging characteristics and treatment response in patients with delayed Wilson disease (WD). Methods Patients with untreated WD (40 with delayed onset and 40 with non?delayed onset) were enrolled. Twenty healthy people were included as normal controls. All patients were evaluated with modified Young scale neural symptom scores, grade of Child liver function and mental symptoms rating scale, magnetic resonance imaging (MRI) scan, magnetic sensitive imaging (susceptibility weighted imaging, SWI), metal metabolism. Corrected phase (CP) was measured at SWI. After 2 week treatment, neurologic symptoms, liver function, and metal metabolism were reviewed. Results The total score of neurological symptoms in WD patients with delayed onset was lower than that of non?delayed onset (13.00 ± 6.87 vs. 21.13 ± 5.53, P=0.033). The scores of SCL?90 and HAMA depression scales in patients with delayed onset were lower than those of non?delayed onset. On T2 weighted imaging, areas including substantia nigra and thalamus, the caudate nucleus, globus pallidus, putamen presented high signal rate in patients with delated onset than those with non?delayed (P=0.022, 0.037, 0.022, 0.037, 0.029 respectively). The SWI CP values of cangbai sphere and shell nucleus in patients with delayed onset were lower than those with non?delayed onset. Patients with delayed onset had higher urinary copper than those with non?delayed onset before and after treatment (P=0.040, 0.036). After treatment, the score of abnormal tremor and gait in patients with delayed onset was decreased (P=0.037, 0.044), while as the occurrence of neurological symptoms was increased by 10%, and the liver function level in patients with delayed WD was decreased in 3 cases. Conclusions The brain of WD patients with delayed onset is mainly composed of metal deposits, however the cell damage is not apparent. Clinical symptoms are characterized by significant liver injury, but relatively mild neurological and psychiatric symptoms. Patients with delayed WD have higher urinary copper excretion than those with non?delayed WD. Chelating agents improves the neurological symptoms in patients with delayed onset.
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Objective To investigate the value of susceptibility weighted imaging (SWI) with T1ρimaging in staging of hepatic fibrosis(HF) in rabbits. Methods Eighty selected white rabbits from New Zealand were randomly divided into the HF group (n=60) and the control group (n=20). Rabbits in the HF group were injected subcutaneously with 50％CCl4 oil solution to establish HF model,and the normal control rabbits were injected with saline solution subcutaneously.The HF group(n=15) and control group(n=5) were randomly selected at the 4th, 5th, 6th and 10th week after injection, to undergo liver MR scan. The liver signal intensity (SI liver), the muscle signal intensity (SI muscle),liver-to-muscle SI ratios (SIR) and liver T1ρvalues were measured. Scheuer was adopted to stage the rabbits in HF. One-way analysis of variance was used to compare the differences between SIR and T1ρ values in different stages of HF pathological. Spearman correlation was used to analyze the correlation between SIR and T1ρ values in the different stage of HF pathological.The ROC were used to compare the efficacy between SIR and T1ρvalues in the diagnosis of HF pathological stage. Results Among the final qualified 68 rabbits in the study, 17 in F0 phase, 11 in F1 phase, 16 in F2 phase, 11 in F3 phase, and 13 in F4 phase. The SIR were (0.977 ± 0.013), (0.960 ± 0.015), (0.802 ± 0.026), (0.786 ± 0.022), (0.541 ± 0.116); T1ρ values were (22.301 ± 1.849), (24.034 ± 0.867), (25.374 ± 1.309),(25.364±1.945),(30.948±2.925) ms.There were statistically significant in SIR between F0 and F2,F0 and F3, F0 and F4, F1 and F2, F1 and F3, F1 and F4, F2 and F4, F3 and F4 (P<0.01). There were statistically significant in T1ρvalues between F0 and F1,F0 and F2,F0 and F3,F0 and F4,F1 and F2,F1 and F4,F2 and F4, F3 and F4(P<0.05). SIR were negatively correlated with HF staging while T1ρ values were positively. ROC showed that the AUC of the T1ρvalues was slightly larger than SIR in the F4 group(0.992>0.966),and the AUC of the SIR was greater than T1ρvalues in the other groups. Conclusion SWI and T1ρvalues can provide an important objective basis in staging of HF. Both of them have great clinical application prospects but SIR diagnostic efficiency is slightly better than that of T1ρvalues.
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PURPOSE: The purpose of this study is to develop a simple method to measure magnetic susceptibility of arbitrarily shaped materials through MR imaging and numerical modeling. MATERIALS AND METHODS: Our 3D printed phantom consists of a lower compartment filled with a gel (gel part) and an upper compartment for placing a susceptibility object (object part). The B0 maps of the gel with and without the object were reconstructed from phase images obtained in a 3T MRI scanner. Then, their difference was compared with a numerically modeled B0 map based on the geometry of the object, obtained by a separate MRI scan of the object possibly immersed in an MR-visible liquid. The susceptibility of the object was determined by a least-squares fit. RESULTS: A total of 18 solid and liquid samples were tested, with measured susceptibility values in the range of −12.6 to 28.28 ppm. To confirm accuracy of the method, independently obtained reference values were compared with measured susceptibility when possible. The comparison revealed that our method can determine susceptibility within approximately 5%, likely limited by the object shape modeling error. CONCLUSION: The proposed gel-phantom-based susceptibility measurement may be used to effectively measure magnetic susceptibility of MR-compatible samples with an arbitrary shape, and can enable development of various MR engineering parts as well as test biological tissue specimens.
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Imageamento por Ressonância Magnética , Métodos , Valores de Referência , Projetos de PesquisaRESUMO
PURPOSE: The effect of global inhomogeneity on quantitative susceptibility mapping (QSM) was investigated. A technique referred to as Simultaneous Unwrapping Phase with Error Recovery from inhomogeneity (SUPER) is suggested as a preprocessing to QSM to remove global field inhomogeneity-induced phase by polynomial fitting. MATERIALS AND METHODS: The effect of global inhomogeneity on QSM was investigated by numerical simulations. Three types of global inhomogeneity were added to the tissue susceptibility phase, and the root mean square error (RMSE) in the susceptibility map was evaluated. In-vivo QSM imaging with volunteers was carried out for 3.0T and 7.0T MRI systems to demonstrate the efficacy of the proposed method. RESULTS: The SUPER technique removed harmonic and non-harmonic global phases. Previously only the harmonic phase was removed by the background phase removal method. The global phase contained a non-harmonic phase due to various experimental and physiological causes, which degraded a susceptibility map. The RMSE in the susceptibility map increased under the influence of global inhomogeneity; while the error was consistent, irrespective of the global inhomogeneity, if the inhomogeneity was corrected by the SUPER technique. In-vivo QSM imaging with volunteers at 3.0T and 7.0T MRI systems showed better definition in small vascular structures and reduced fluctuation and non-uniformity in the frontal lobes, where field inhomogeneity was more severe. CONCLUSION: Correcting global inhomogeneity using the SUPER technique is an effective way to obtain an accurate susceptibility map on QSM method. Since the susceptibility variations are small quantities in the brain tissue, correction of the inhomogeneity is an essential element for obtaining an accurate QSM.
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Humanos , Encéfalo , Lobo Frontal , Imageamento por Ressonância Magnética , Métodos , VoluntáriosRESUMO
Objective To analyze the changes of susceptibility in acute cerebral ischemia (ACI) using quantitative susceptibility mapping (QSM).Methods Twenty-three patients with ACI who met the criteria underwent conventional brain MR and QSM scan,and the susceptibility maps were obtained with QSM post-processing software in image processing workstation.According to DWI images,ROIs were manually drawn on lesions of ACI to obtain magnetic susceptibility on susceptibility map,including cortical gray matter (CGM),subcortical white matter (SWM),caudate (CA),globus pallidus (GP),putamen (PU),thalamus (TH),substantia nigra (SN),dentate nucleus (DN) and pons (PO).Then magnetic susceptibility of contralateral position was obtained.According to whether cerebral microbleeds (CMBs) were observed,the ACI patients were divided into CMBs group and non-CMBs group.The magnetic susceptibility of groups and different ROIs of ACI and the contralateral area were compared statistically.Results There was significant difference in magnetic susceptibility between CMBs group [(79.04 ± 52.25) × 10-9 ppd] and non-CMBs group ([-4.01 ± 44.57] × 10 9 ppd;Z=-3.297,P =0.001).The difference of magnetic susceptibility between the lesion side and the contralateral side ([-12.10±16.75]× 10-9 ppd) was statistically significant in CMBs group (Z=-3.296,P=0.001),but not in non-CMBs group (contralateral side [1.61 ±32.77] × 10-9 ppd;Z=-0.157,P=0.875).According to the location of ROIs,magnetic susceptibility had statistical differences only in PO,CGM and contralateral side (Z=-2.023,--3.130,P=0.043,0.002).Conclusion QSM can be used to quantitatively analyze magnetic susceptibility of ACI lesions and find CMBs,therefore is helpful to guiding treatment.
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Objective:To analyze the imaging features of magnetic susceptibility-weighted imaging (SWI) in the patients with cerebral amyloid angiopathy-related hemorrhage (CAAH),and to clarify the diagnostic value of SWI for CAAH.Methods:A total of 68 patients presumptively diagnosed as CAAH were collected,and their imaging data of routine MRI and SWI were collected and analyzed.The detection rates of hemorrhage focus of the CAAH patients were compared between two kinds of imaging examination.The consistency of detection of CAAH by routine MRI and SWI was analyzed.The imaging features of SWI and the risk of focus hemorrhage in the patients with CAAH were analyzed by multivariate Logistic regression analysis.Results:Sixty-one patients were confirmed as CAAH by pathologic diagnosis,and 53 patients were confirmed as CAAH by routine MRI;the detection rate was 86.89％;59 cases of hemorrhage focus were confirmed by SWI and the detection rate was 96.72％.The number of lesions detected by SWI was more than that of routine MRI (P＜0.05).The consistency of detection of CAAH by routine MRI and SWI was poor,and the value of Kappa was 0.3666.The patchy high signal and multiple clear edge low signal area were the relative imaging features of CAAH with SWI in the patients with CAAH analyzed by multivariate Logistic regression analysis (OR=3.895,P=0.025;OR=3.124,P=0.029).Conclusion:SWI can efficiently detect the hemorrhage focus in the patients with CAAH and the diagnostic value is better than routine MRI.
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Objective:To analyze the imaging features of magnetic susceptibility-weighted imaging (SWI) in the patients with cerebral amyloid angiopathy-related hemorrhage (CAAH),and to clarify the diagnostic value of SWI for CAAH.Methods:A total of 68 patients presumptively diagnosed as CAAH were collected,and their imaging data of routine MRI and SWI were collected and analyzed.The detection rates of hemorrhage focus of the CAAH patients were compared between two kinds of imaging examination.The consistency of detection of CAAH by routine MRI and SWI was analyzed.The imaging features of SWI and the risk of focus hemorrhage in the patients with CAAH were analyzed by multivariate Logistic regression analysis.Results:Sixty-one patients were confirmed as CAAH by pathologic diagnosis,and 53 patients were confirmed as CAAH by routine MRI;the detection rate was 86.89％;59 cases of hemorrhage focus were confirmed by SWI and the detection rate was 96.72％.The number of lesions detected by SWI was more than that of routine MRI (P＜0.05).The consistency of detection of CAAH by routine MRI and SWI was poor,and the value of Kappa was 0.3666.The patchy high signal and multiple clear edge low signal area were the relative imaging features of CAAH with SWI in the patients with CAAH analyzed by multivariate Logistic regression analysis (OR=3.895,P=0.025;OR=3.124,P=0.029).Conclusion:SWI can efficiently detect the hemorrhage focus in the patients with CAAH and the diagnostic value is better than routine MRI.
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Objective To explore the changes of susceptibility of different sides and gender in healthy young adults with quantitative susceptibility mapping (QSM).Methods Totally 41 healthy young right-handed adults underwent conventional brain MRI and QSM scan,and the susceptibility maps were obtained by the image post-processing software.Then the ROI of the bilateral frontal grey matter (FGM),frontal white matter (FWM),caudate (CA),globus pallidus (GP),putamen (PU),thalamus (TH),substantia nigra (SN),red nucleus (RN),dentate nucleus (DN),pons (PO),corpus callosum (CC) were manually drawn to obtain magnetic susceptibility on the susceptibility map.The magnetic susceptibility of each ROI was compare between both sides,as well as gender by Mann-Whitney test.Results The magnetic susceptibility of the bilateral ROI of GP was the highest,and SN was followed,FWM was minimum.The susceptibility of bilateral FGM,FWM,CA,GP,PU,TH,SN,RN,DN,PO,CC had no statistically significant differences (all P＞0.05).The magnetic susceptibility in CA of different gender had statistically significant difference (P＜0.05).Conclusion The brain magnetic susceptibility.can be measured by QSM,and it can assess brain iron content quantitatively.
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Objective: To present a detailed explanation on the processing of magnetic susceptibility weighted imaging (SWI), demonstrating the effects of echo time and sensitive mask on the differentiation between calcification and hemosiderin. Materials and Methods: Computed tomography and magnetic resonance (magnitude and phase) images of six patients (age range 41– 54 years; four men) were retrospectively selected. The SWI images processing was performed using the Matlab’s own routine. Results: Four out of the six patients showed calcifications at computed tomography images and their SWI images demonstrated hyperintense signal at the calcification regions. The other patients did not show any calcifications at computed tomography, and SWI revealed the presence of hemosiderin deposits with hypointense signal. Conclusion: The selection of echo time and of the mask may change all the information on SWI images, and compromise the diagnostic reliability. Amongst the possible masks, the authors highlight that the sigmoid mask allows for contrasting calcifications and hemosiderin on a single SWI image. .
Objetivo: Expor em detalhes o processamento da imagem ponderada em suscetibilidade magnética (susceptibility weighted imaging – SWI), destacando o efeito da escolha do tempo de eco e da máscara sensível à diferenciação de calcificação e hemossiderina simultaneamente. Materiais e Métodos: Imagens de tomografia computadorizada e por ressonância magnética (magnitude e fase) foram selecionadas, retrospectivamente, de seis pacientes (idades entre 41 e 54 anos; quatro homens). O processamento das imagens SWI foi realizado em rotina própria no programa Matlab. Resultados: Dos seis pacientes estudados, quatro apresentaram calcificações nas imagens de tomografia computadorizada. Nestes, as imagens SWI mostraram sinal hiperintenso para as regiões de calcificações. Os outros dois pacientes não apresentaram calcificações nas imagens de tomografia computadorizada e apresentaram depósito de hemossiderina com sinal hipointenso na imagem SWI. Conclusão: A escolha do tempo de eco e da máscara pode alterar toda a informação da imagem SWI e comprometer a confiabilidade diagnóstica. Dentre as possíveis máscaras, destacamos que a máscara sigmoide permite contrastar calcificação e hemossiderina em uma única imagem SWI. .
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Animais , Camundongos , Processamento Alternativo/genética , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Proteína de Ligação a Regiões Ricas em Polipirimidinas/genética , Tropomiosina/genética , Sequência de Bases , Sítios de Ligação , Primers do DNA , Éxons , Vetores Genéticos , Ligantes , Fases de Leitura Aberta , Reação em Cadeia da Polimerase , Proteína de Ligação a Regiões Ricas em Polipirimidinas/metabolismo , Proteínas Recombinantes/metabolismo , Proteínas Repressoras/metabolismo , TransfecçãoRESUMO
As condições climáticas atuais indicam avanço da vegetação de floresta sobre os campos na região dos Campos de Cima da Serra no Rio Grande do Sul. Essa mudança na vegetação altera o conteúdo de matéria orgânica e a umidade do solo. Este estudo objetivou avaliar os óxidos de ferro pedogênicos em um Latossolo sob campo e floresta nativa e relacionar os mesmos com os teores de carbono orgânico e a área superficial específica do solo. Os teores de carbono orgânico são maiores no solo sob floresta e, possivelmente, influenciaram processos dissolutivos de óxidos de ferro cristalinos e a neoformação de tipos metaestáveis de baixa cristalinidade. O incremento de C orgânico no solo sob floresta elevou expressivamente a área superficial específica do solo, mascarando o efeito geralmente positivo dos óxidos de Fe sobre essa característica física.
The current weather conditions indicate a substitution of grassland by forest vegetation in the Campos de Cima da Serra in Rio Grande do Sul, Brazil. This change in vegetation changes the contents of soil organic matter and soil moisture. This study aimed to evaluate the pedogenetic iron oxides in an Oxisol under native forest and grassland and its relationship with soil total organic carbon content and soil specific surface area. Replacing grassland with native forest resulted in an accumulation of soil organic carbon and possibly influenced dissolutive processes of crystalline iron oxides types and neoformation of metastable types of low crystallinity. In native forest soil, the increase of total organic carbon increased the soil specific surface area, masking the positive effect of iron oxides on this physical characteristic.
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Objective To evaluate the performance of PROPELLER diffusion-weighted magnetic resonance image (DWI) in reducing image distortion caused by susceptibility artifacts. Methods Forty volunteers with metal denture were enrolled in the present study; their PROPELLER and echo-planar DWI were taken for the skull base. The quality of each image was evaluated by using a four-point scoring system. Qualitative comparison of image distortion between PROPELLER DWI and echo-planar DWI was performed by ROC analysis. Results The area under the ROC curve was 0.979 (P<0.01), indicating a significant difference in the image distortion between PROPELLER DWI and echo-planar DWI. PROPELLER technique could greatly reduce the image distortion associated with magnetic susceptibility artifacts. Conclusion PROPELLER technique can greatly reduce metal denture-induced susceptibility-related image distortion, and ROC curve can be used for quantitative analysis of subjective assessment of image quality.