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1.
Radiol Med ; 125(11): 1056-1071, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32946001

RESUMO

Cardiomyopathies are a heterogeneous entity. The progress in the field of genetics has allowed over the years to determine its origin more and more often. The classification of these pathologies has changed over the years; it has been updated with new knowledge. Imaging allows to define the phenotypic characteristics of the different forms of cardiomyopathy. Cardiac magnetic resonance (CMR) allows a morphological evaluation of the associated (and sometimes pathognomonic) cardiac findings of any form of cardiomyopathy. The tissue characterization sequences also make magnetic resonance imaging unique in its ability to detect changes in myocardial tissue. This review aims to define the features that can be highlighted by CMR in hypertrophic and dilated forms and the possible differential diagnoses. In hypertrophic forms, CMR provides: precise evaluation of wall thickness in all segments, ventricular function and size and evaluation of possible presence of areas of fibrosis as well as changes in myocardial tissue (measurement of T1 mapping and extracellular volume values). In dilated forms, cardiac resonance is the gold standard in the assessment of ventricular volumes. CMR highlights also the potential alterations of the myocardial tissue.


Assuntos
Técnicas de Imagem Cardíaca/métodos , Cardiomiopatia Dilatada/diagnóstico por imagem , Cardiomiopatia Hipertrófica/diagnóstico por imagem , Imagem por Ressonância Magnética/métodos , Adulto , Idoso , Cardiomiopatia Dilatada/genética , Cardiomiopatia Hipertrófica/genética , Meios de Contraste , Diagnóstico Diferencial , Feminino , Gadolínio , Septos Cardíacos/diagnóstico por imagem , Septos Cardíacos/patologia , Humanos , Hipertrofia/diagnóstico por imagem , Hipertrofia/patologia , Aumento da Imagem/métodos , Masculino , Pessoa de Meia-Idade
2.
Br J Radiol ; 93(1115): 20200751, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32915647

RESUMO

Objective:The aim of this study was to predict response to neoadjuvant chemotherapy (NAC) in patients with locally advanced hypopharyngeal cancer by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI).Methods:A retrospective study enrolled 46 diagnosed locally advanced hypopharyngeal cancer. DCE-MRI were performed prior to and after two cycles of NAC. The volume transfer constant (Ktrans), extracellular extravascular volume fraction (Ve), and plasma volume fraction (Kep) were computed from primary tumors. DCE-MRI parameters were used to measure tumor response according to the Response Evaluation Criteria in Solid Tumors criteria (RECIST).Results:After 2 NAC cycles, 30 out of 46 patients were categorized into the responder group, whereas the other 16 were categorized into non-responder group. Compared with the pretreatment value, the post-treatment Ktrans and Kep was significantly lower (P < 0.05), but no significant change in Ve (P > 0.05). Compared with non-responders, a notably higher pretreatment Ktrans, Kep, lower post-treatment Ktrans, higher ΔKtrans and ΔKep were observed in responders (all P < 0.05). While the pretreatment Ve, post-treatment Ve, and ΔVe did not differ significantly (P>0.05) between the two groups. The receiver operating characteristic curve analysis revealed that pretreatment Ktrans of 0.202/min is the most optimal cut-off in predicting response to chemotherapy, resulting in an AUC of 0.837 and corresponding sensitivity and specificity of 76.7%, and 81.1%, respectively.Conclusion:DCE-MRI especially pretreatment Ktrans can potentially predict the treatment response to neoadjuvant chemotherapy for hypopharyngeal cancer.Advances in knowledge:Few studies of DCE-MRI on hypopharyngeal cancer treated with chemoradiation reported. The results demonstrate that DCE-MRI especially pretreatment Ktrans may be more potential value in predicting the treatment response to neoadjuvant chemotherapy for hypopharyngeal cancer.


Assuntos
Meios de Contraste , Neoplasias Hipofaríngeas/diagnóstico por imagem , Neoplasias Hipofaríngeas/tratamento farmacológico , Aumento da Imagem/métodos , Imagem por Ressonância Magnética/métodos , Terapia Neoadjuvante/métodos , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Carcinoma de Células Escamosas/irrigação sanguínea , Carcinoma de Células Escamosas/diagnóstico por imagem , Carcinoma de Células Escamosas/tratamento farmacológico , Quimioterapia Adjuvante/métodos , Cisplatino/administração & dosagem , Feminino , Humanos , Neoplasias Hipofaríngeas/irrigação sanguínea , Masculino , Pessoa de Meia-Idade , Paclitaxel/administração & dosagem , Curva ROC , Critérios de Avaliação de Resposta em Tumores Sólidos , Estudos Retrospectivos , Resultado do Tratamento
3.
Medicine (Baltimore) ; 99(35): e21907, 2020 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-32871924

RESUMO

BACKGROUND: Superb microvascular imaging (SMI) is a novel Doppler technique that depicts low velocity blood flow without the use of a contrast agent. Studies suggested that SMI may or may not detect neovascularization of carotid plaque with accuracy comparable to contrast-enhanced ultrasound. To gain clarity, a meta-analysis to systematically review and synthesize relevant data on the SMI for the detection of intraplaque neovascularization was undertaken. METHODS: We will search PubMed, Web of Science, Cochrane Library, and Chinese biomedical databases from their inceptions to the June 31, 2020, without language restrictions. Two authors will independently carry out searching literature records, scanning titles and abstracts, full texts, collecting data, and assessing risk of bias. Review Manager 5.2 and Stata14.0 software will be used for data analysis. RESULTS: This systematic review will investigate whether SMI is feasible on the detection of intraplaque neovascularization compared with contrast-enhanced ultrasound. CONCLUSION: Its findings will provide helpful evidence for the feasibility of SMI on the detection of intraplaque neovascularization. SYSTEMATIC REVIEW REGISTRATION: INPLASY202070097.


Assuntos
Artérias Carótidas/diagnóstico por imagem , Artérias Carótidas/patologia , Metanálise como Assunto , Neovascularização Patológica/diagnóstico por imagem , Placa Aterosclerótica/diagnóstico por imagem , Placa Aterosclerótica/patologia , Revisões Sistemáticas como Assunto , Velocidade do Fluxo Sanguíneo , Meios de Contraste , Estudos de Viabilidade , Humanos , Aumento da Imagem/métodos , Microvasos/diagnóstico por imagem , Ultrassonografia/métodos
4.
PLoS One ; 15(9): e0238294, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32870940

RESUMO

The proposed method is to do simplification for Digital Elevation Model (DEM), which uses a few of original nodes representing the terrain surface while maintaining the accuracy. The original DEM nodes are sampled using the Maximal Poisson-disk Sampling (MPS), in which, the disk's size of each sample is computed on basis of the Singular Value Decomposition (SVD). MPS can generate the hyper-uniformly distributed samples and was taken to do DEM adaptive sampling by being combined with the geodesic metric. However, the geodesic distance computation is complex and the requirement for memory is high. As such, this paper proposes an extension of the classic MPS based method for selecting quasi-randomly distributed points from DEM nodes based on the distribution of eigenvalues, accounting for surface heterogeneity. To achieve this objective, uniform MPS is conducted to sample the DEM nodes by setting the related disk radius to be inversely proportional to the local terrain complexity, which is defined as an index expressing the local terrain variation. Then, the geodesic metric related parameters are implicitly contained in the defined index. As a result, more samples are concentrated in the rugged regions, and vice versa. The proposed method shows better perfermance, at least the results are comparable with the geodesic distance based Poisson disk sampling method. Meanwhile, it greatly accelerates the sampling process and reduces the memory cost.


Assuntos
Algoritmos , Aumento da Imagem/métodos , Fotogrametria
5.
PLoS One ; 15(9): e0238259, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32870943

RESUMO

This paper presents an improved method to estimate the blur parameters of motion deblurring algorithm for single image restoration based on the point spread function (PSF) in frequency spectrum. We then introduce a modification to the Radon transform in the blur angle estimation scheme with our proposed difference value vs angle curve. Subsequently, the auto-correlation matrix is employed to estimate the blur angle by measuring the distance between the conjugated-correlated troughs. Finally, we evaluate the accuracy, robustness and time efficiency of our proposed method with the existing algorithms on the public benchmarks and the natural real motion blurred images. The experimental results demonstrate that the proposed PSF estimation scheme not only could obtain a higher accuracy for the blur angle and blur length, but also demonstrate stronger robustness and higher time efficiency under different circumstances.


Assuntos
Algoritmos , Aumento da Imagem/métodos , Fotografação
6.
Yonsei Med J ; 61(10): 895-900, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32975065

RESUMO

The purpose of this study was to evaluate the diagnostic performance of magnetic resonance (MR) radiomics-based machine learning algorithms in differentiating squamous cell carcinoma (SCC) from lymphoma in the oropharynx. MR images from 87 patients with oropharyngeal SCC (n=68) and lymphoma (n=19) were reviewed retrospectively. Tumors were semi-automatically segmented on contrast-enhanced T1-weighted images registered to T2-weighted images, and radiomic features (n=202) were extracted from contrast-enhanced T1- and T2-weighted images. The radiomics classifier was built using elastic-net regularized generalized linear model analyses with nested five-fold cross-validation. The diagnostic abilities of the radiomics classifier and visual assessment by two head and neck radiologists were evaluated using receiver operating characteristic (ROC) analyses for distinguishing SCC from lymphoma. Nineteen radiomics features were selected at least twice during the five-fold cross-validation. The mean area under the ROC curve (AUC) of the radiomics classifier was 0.750 [95% confidence interval (CI), 0.613-0.887], with a sensitivity of 84.2%, specificity of 60.3%, and an accuracy of 65.5%. Two human readers yielded AUCs of 0.613 (95% CI, 0.467-0.759) and 0.663 (95% CI, 0.531-0.795), respectively. The radiomics-based machine learning model can be useful for differentiating SCC from lymphoma of the oropharynx.


Assuntos
Carcinoma de Células Escamosas/diagnóstico por imagem , Linfoma/diagnóstico por imagem , Imagem por Ressonância Magnética/métodos , Neoplasias Orofaríngeas/diagnóstico por imagem , Orofaringe/diagnóstico por imagem , Algoritmos , Biópsia , Carcinoma de Células Escamosas/patologia , Feminino , Humanos , Aumento da Imagem/métodos , Linfoma/patologia , Aprendizado de Máquina , Neoplasias Orofaríngeas/patologia , Orofaringe/patologia , Curva ROC , Estudos Retrospectivos , Sensibilidade e Especificidade , Resultado do Tratamento
7.
Phys Med Biol ; 65(18): 185006, 2020 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-32924973

RESUMO

Previous studies have demonstrated the feasibility of reducing noise with deep learning-based methods for low-dose fluorodeoxyglucose (FDG) positron emission tomography (PET). This work aimed to investigate the feasibility of noise reduction for tracers without sufficient training datasets using a deep transfer learning approach, which can utilize existing networks trained by the widely available FDG datasets. In this study, the deep transfer learning strategy based on a fully 3D patch-based U-Net was investigated on a 18F-fluoromisonidazole (18F-FMISO) dataset using single-bed scanning and a 68Ga-DOTATATE dataset using whole-body scanning. The datasets of 18F-FDG by single-bed scanning and whole-body scanning were used to obtain pre-trained U-Nets separately for subsequent cross-tracer and cross-protocol transfer learning. The full-dose PET images were used as the labels while low-dose PET images from 10% counts were used as the inputs. Three types of U-Nets were obtained: a U-Net trained by FDG dataset, a pre-trained FDG U-Net fine-tuned by another less-available tracer (FMISO/DOATATE), and a U-Net completely trained by a large number of less-available tracer datasets (FMISO/DOATATE), used as the reference U-Net. The denoising performance of the three types of U-Nets was evaluated on single-bed 18F-FMISO and whole-body 68Ga-DOTATATE separately and compared using normalized root-mean-square error (NRMSE), signal-to-noise ratio (SNR), and relative bias of region of interest (ROI). For cross-tracer transfer learning, all the U-Nets provided denoised images with similar quality for both tracers. There was no significant difference in terms of NRMSE and SNR when comparing the former two U-Nets with the reference U-Net. The ROI biases for these U-Nets were similar. For cross-tracer and cross-protocol transfer learning, the pre-trained single-bed FDG U-Net fine-tuned by whole-body DOTATATE data provided the most consistent images with the reference U-Net. Fine-tuning significantly reduced the NRMSE and the ROI bias and improved the SNR when comparing the fine-tuned U-Net with the U-Net trained by single-bed FDG only (NRMSE: 96.3% ± 21.1% versus 120.6% ± 18.5%, ROI bias: -10.5% ± 13.0% versus -14.7% ± 6.4%, SNR: 4.2 ± 1.4 versus 3.9 ± 1.6, for fine-tuned U-Net and the U-Net trained by single-bed FDG, respectively, with p < 0.01 in all cases). This work demonstrated that it is feasible to utilize existing networks well-trained by FDG datasets to reduce the noise for other less-available tracers and other scanning protocols by using the fine-tuning strategy.


Assuntos
Aprendizado Profundo , Aumento da Imagem/métodos , Tomografia por Emissão de Pósitrons , Doses de Radiação , Razão Sinal-Ruído , Humanos
8.
Br J Radiol ; 93(1115): 20200514, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32795180

RESUMO

Takotsubo cardiomyopathy (TC) is a reversible condition in which there is transient left ventricular (LV) dysfunction characterised most commonly by basal hyperkinesis and mid-apical LV ballooning and hypokinesia. It is said to be triggered by stress and mimics, such as acute coronary syndrome (ACS) clinically. Diagnosis is usually suspected on echocardiography due to the characteristic contraction pattern in a patient with symptoms and signs of ACS but normal coronary arteries on catheter angiography. Cardiac magnetic resonance (CMR), with its latest advancements, is the diagnostic modality of choice for diagnosis, prognosis and follow-up of patients. The advances in CMR (including T1, T2, ECV mapping and threshold-based late gadolinium enhancement (LGE) measurements have revolutionised the role of CMR in tissue characterisation and prognostication in patients with TC. In this review, we highlight the current role of CMR in management of TC and enumerate the CMR findings in TC as well the current advances in the field of CMR, which could help in prognosticating these patients.


Assuntos
Algoritmos , Imagem por Ressonância Magnética/métodos , Cardiomiopatia de Takotsubo/diagnóstico por imagem , Circulação Coronária , Edema Cardíaco/diagnóstico por imagem , Fibrose/diagnóstico por imagem , Gadolínio , Humanos , Aumento da Imagem/métodos , Imagem por Ressonância Magnética/tendências , Imagem Cinética por Ressonância Magnética , Contração Miocárdica , Miocárdio/patologia , Cardiomiopatia de Takotsubo/etiologia , Cardiomiopatia de Takotsubo/fisiopatologia
9.
Radiol Clin North Am ; 58(5): 875-884, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32792120

RESUMO

Indeterminate renal masses remain a diagnostic challenge for lesions not initially characterized as angiomyolipoma or Bosniak I/II cysts. Differential for indeterminate renal masses include oncocytoma, fat-poor angiomyolipoma, and clear cell, papillary, and chromophobe renal cell carcinoma. Qualitative and quantitative techniques using data derived from multiphase contrast-enhanced imaging have provided methods for specific differentiation and subtyping of indeterminate renal masses, with emerging applications such as radiocytogenetics. Early and accurate characterization of indeterminate renal masses by multiphase contrast-enhanced imaging will optimize triage of these lesions into surgical, ablative, and active surveillance treatment plans.


Assuntos
Interpretação de Imagem Assistida por Computador/métodos , Neoplasias Renais/diagnóstico por imagem , Neoplasias Renais/patologia , Imagem por Ressonância Magnética/métodos , Tomografia Computadorizada por Raios X/métodos , Meios de Contraste , Diagnóstico Diferencial , Humanos , Aumento da Imagem/métodos , Rim/diagnóstico por imagem , Rim/patologia , Triagem
10.
Radiol Clin North Am ; 58(5): 885-896, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32792121

RESUMO

There are several potential pitfalls that radiologists face when interpreting images of the kidneys. Some result from image acquisition and can arise from the imaging equipment or imaging technique, whereas others are patient related. Another category of pitfalls relates to image interpretation. Some difficulties stem from methods to detect enhancement after contrast administration, whereas others are benign entities that can mimic a renal tumor. Finally, interpretation and diagnosis of fat-containing renal masses may be tricky due to the complexities discerning the pattern of fat within a mass and how that translates to an accurate diagnosis.


Assuntos
Neoplasias Renais/diagnóstico por imagem , Imagem por Ressonância Magnética/métodos , Tomografia Computadorizada por Raios X/métodos , Meios de Contraste , Diagnóstico Diferencial , Humanos , Aumento da Imagem/métodos , Rim/diagnóstico por imagem , Reprodutibilidade dos Testes
11.
Radiol Clin North Am ; 58(5): 935-949, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32792125

RESUMO

An introduction to the expanding modality of contrast-enhanced ultrasound is provided, along with basics on contrast agents and technique. The contrast ultrasound findings of multiple renal tumors are reviewed with examples, including clear cell renal cell carcinoma, papillary renal cell carcinoma, chromophobe renal cell carcinoma, other rare renal cell carcinoma subtypes, oncocytoma, upper tract urothelial carcinoma, lymphoma, and angiomyolipoma, followed also by brief discussions of renal infections and pseudolesions.


Assuntos
Meios de Contraste , Aumento da Imagem/métodos , Neoplasias Renais/diagnóstico por imagem , Ultrassonografia/métodos , Diagnóstico Diferencial , Humanos , Rim/diagnóstico por imagem , Sensibilidade e Especificidade
12.
Br J Radiol ; 93(1115): 20191035, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32649224

RESUMO

OBJECTIVE: To evaluate multiparametric MRI for differentiating benign and malignant soft tissue tumors. METHODS: This retrospective study included 67 patients (mean age, 55 years; 18-82 years) with 35 benign and 32 malignant soft tissue tumors. Intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI)-derived parameters (D, D*, f), apparent diffusion coefficient (ADC), and dynamic contrast-enhanced (DCE)-MRI parameters (Ktrans, Kep, Ve, iAUC) were calculated. Myxoid and non-myxoid soft tissue tumors were divided for subgroup analysis. The parameters were compared between benign and malignant tumors. RESULTS: ADC and D were significantly lower in malignant than benign soft tissue tumors (1170 ± 488 vs 1472 ± 349 µm2/s; 1132 ± 500 vs 1415 ± 374 µm2/s; p < 0.05). Ktrans, Kep, Ve, and iAUC were significantly different between malignant and benign soft tissue tumors (0.209 ± 0.160 vs 0.092 ± 0.067 min-1; 0.737 ± 0.488 vs 0.311 ± 0.230 min-1; 0.32 ± 0.17 vs 0.44 ± 0.28; 0.23 ± 0.14 vs 0.12 ± 0.09, p < 0.05, respectively). ADC (0.752), D (0.742), and Kep (0.817) had high AUCs. Subgroup analysis showed that only Ktrans, and iAUC were significantly different in myxoid tumors, while, ADC, D, Ktrans, Kep, and iAUC were significantly different in non-myxoid tumor for differentiating benign and malignant tumors. D, Kep, and iAUC were the most significant parameters predicting malignant soft tissue tumors. CONCLUSION: Multiparametric MRI can be useful to differentiate benign and malignant soft tissue tumors using IVIM-DWI and DCE-MRI. ADVANCES IN KNOWLEDGE: 1. Pure tissue diffusion (D), transfer constant (Ktrans), rate constant (Kep), and initial area under time-signal intensity curve (iAUC) can be used to differentiate benign malignant soft tissue tumors.2. Ktrans and iAUC enable differentiation of benign and malignant myxoid soft tissue tumors.


Assuntos
Imageamento por Ressonância Magnética Multiparamétrica/métodos , Neoplasias de Tecidos Moles/diagnóstico por imagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Área Sob a Curva , Meios de Contraste , Diagnóstico Diferencial , Imagem de Difusão por Ressonância Magnética/métodos , Imagem de Tensor de Difusão , Feminino , Humanos , Aumento da Imagem/métodos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Curva ROC , Estudos Retrospectivos , Neoplasias de Tecidos Moles/irrigação sanguínea , Neoplasias de Tecidos Moles/classificação , Adulto Jovem
13.
Br J Radiol ; 93(1114): 20190710, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32706981

RESUMO

OBJECTIVE: Limited visibility of post-resection muscle-invasive bladder cancer (MIBC) on CT hinders radiotherapy dose escalation of the residual tumour. Diffusion-weighted MRI (DW-MRI) visualises areas of high tumour burden and is increasingly used within diagnosis and as a biomarker for cancer. DW-MRI could, therefore, facilitate dose escalation, potentially via dose-painting and/or accommodating response. However, the distortion inherent in DW-MRI could limit geometric accuracy. Therefore, this study aims to quantify DW-MRI distortion via imaging of a bladder phantom. METHODS: A phantom was designed to mimic MIBC and imaged using CT, DW-MRI and T2W-MRI. Fiducial marker locations were compared across modalities and publicly available software was assessed for correction of magnetic susceptibility-related distortion. RESULTS: Fiducial marker locations on CT and T2W-MRI agreed within 1.2 mm at 3 T and 1.8 mm at 1.5 T. The greatest discrepancy between CT and apparent diffusion coefficient (ADC) maps was 6.3 mm at 3 T, reducing to 1.8 mm when corrected for distortion. At 1.5 T, these values were 3.9 mm and 1.7 mm, respectively. CONCLUSIONS: Geometric distortion in DW-MRI of a model bladder was initially >6 mm at 3 T and >3 mm at 1.5 T; however, established correction methods reduced this to <2 mm in both cases. ADVANCES IN KNOWLEDGE: A phantom designed to mimic MIBC has been produced and used to show distortion in DW-MRI can be sufficiently mitigated for incorporation into the radiotherapy pathway. Further investigation is therefore warranted to enable individually adaptive image-guided radiotherapy of MIBC based upon DW-MRI.


Assuntos
Imagem de Difusão por Ressonância Magnética/métodos , Aumento da Imagem/métodos , Imagens de Fantasmas , Radioterapia Guiada por Imagem , Neoplasias da Bexiga Urinária/diagnóstico por imagem , Neoplasias da Bexiga Urinária/radioterapia , Marcadores Fiduciais , Humanos , Invasividade Neoplásica , Tomografia Computadorizada por Raios X , Neoplasias da Bexiga Urinária/patologia
14.
Br J Radiol ; 93(1112): 20190725, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32516546

RESUMO

OBJECTIVE: To compare htree-dimensional CAIPIRINHA SPACE and two-dimensional turbo spin echo (2D TSE) MRI in the diagnosis of knee pathology in symptomatic adult patients. METHODS: From February to September in 2018, 120 patients who underwent a knee MRI using both 3D CAIPIRINHA SPACE and 2D TSE MRI were enrolled. The signal-to-noise ratios (SNRs) and contrast-to-noise ratio (CNR) of the 2D and 3D MRI were compared using a paired t-test. Two radiologists independently evaluated both 2D and 3D MRI images using scoring systems for the menisci, ligaments, and cartilage. Intermethod, inter- and intrareader agreements were determined using an intraclass correlation coefficient (ICC). The diagnostic performance of both methods was measured in 44 patients with arthroscopy. RESULTS: The mean scan time of 3D CAIPIRINHA SPACE MRI (4' 43") was shorter than that of 2D TSE MRI (17' 27"). The mean SNR and CNR of 3D CAIPIRINHA SPACE was higher than those of 2D TSE MRI (mean difference, 3.97 of SNR and 1.58 of CNR; p < 0.001 and p = .038, respectively). Intermethod (ICC, 0.84-1.0) and inter-reader (ICC, 0.75-0.97), and intra-reader agreements (ICC, 0.87-1.0) were good or excellent. The diagnostic accuracy of 3D CAIPIRINHA SPACE sequence was equal for ligament (95.5%) and better for meniscal and cartilage evaluation (84.1% each), compared to 2D TSE MRI (79.5% each). CONCLUSION: The fat-suppressed 3D CAIPIRINHA SPACE MRI maybe useful in clinical practice for the evaluation of the knee in place of the 2D conventional MRI protocol. ADVANCES IN KNOWLEDGE: 1. The 3D CAIPIRINHA SPACE MRI of the knee joint may be acceptable to be used in clinical practice showing comparable imaging quality compared to conventional 2D TSE MRI.2. Compared with arthroscopic findings as the gold-standard, the diagnostic performance of 3D CAIPIRINHA SPACE MRI was equal or better for knee joint evaluation than that of 2D TSE MRI, as well as with shorter scan time.


Assuntos
Joelho/diagnóstico por imagem , Imagem por Ressonância Magnética/métodos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Meios de Contraste , Feminino , Humanos , Aumento da Imagem/métodos , Imageamento Tridimensional , Joelho/patologia , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Razão Sinal-Ruído , Adulto Jovem
15.
Zhonghua Zhong Liu Za Zhi ; 42(6): 469-473, 2020 Jun 23.
Artigo em Chinês | MEDLINE | ID: mdl-32575942

RESUMO

Objective: To investigate the characteristics of contrast-enhanced ultrasound (CEUS) in alpha-fetoprotein (AFP)-negative recurrent small hepatocellular carcinoma (rsHCC). Methods: The imaging characteristics of CEUS were retrospectively analyzed in 132 lesions from 116 patients with rsHCC, including 59 lesions from 51 AFP-negative patients and 73 lesions from 65 AFP-positive patients. The hemodynamic parameters such as contrast-enhanced onset time, time-to-peak, isoenhancement start time, low-enhancement start time, and perfusion mode were compared between two groups. Results: The time-to-peak, isoenhancement start time, low-enhancement start time of AFP-negative group were significantly increased than those in AFP-positive group (23.22±5.08)s vs. (20.30±3.41)s, (59.44±39.75)s vs. (40.75±16.16)s, (102.89±44.45)s vs. (87.08±25.27)s (all of P<0.05). Meanwhile, the proportion of isoenhancement during the portal and late phases in AFP-negative group was significantly higher than those in AFP-positive group (59.3% vs. 37.0%, 16.9% vs. 4.1%; all of P<0.05). However, there was no significant difference between the two groups in the enhancement start time (14.87±6.00)s vs. (14.35±5.30)s (P>0.05) as well as isoenhancement proportion in the arterial phase (94.9% vs. 98.6%, P>0.05). Conclusions: The enhancement pattern of CEUS in AFP-negative rsHCC patients was "fast-in and slow-out" with a diverse and atypical trend. Recognizing its regular features will facilitate the early detection of AFP-negative rsHCC.


Assuntos
Carcinoma Hepatocelular/diagnóstico por imagem , Meios de Contraste , Neoplasias Hepáticas/diagnóstico por imagem , Ultrassonografia/métodos , Carcinoma Hepatocelular/diagnóstico , Humanos , Aumento da Imagem/métodos , Neoplasias Hepáticas/diagnóstico , Neoplasias Hepáticas/patologia , Estudos Retrospectivos , alfa-Fetoproteínas
16.
PLoS One ; 15(6): e0233209, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32497135

RESUMO

The impact of a method for MR-based respiratory motion correction of PET data on lesion visibility and quantification in patients with oncologic findings in the lung was evaluated. Twenty patients with one or more lesions in the lung were included. Hybrid imaging was performed on an integrated PET/MR system using 18F-FDG as radiotracer. The standard thoracic imaging protocol was extended by a free-breathing self-gated acquisition of MR data for motion modelling. PET data was acquired simultaneously in list-mode for 5-10 mins. One experienced radiologist and one experienced nuclear medicine specialist evaluated and compared the post-processed data in consensus regarding lesion visibility (scores 1-4, 4 being best), image noise levels (scores 1-3, 3 being lowest noise), SUVmean and SUVmax. Motion-corrected (MoCo) images were additionally compared with gated images. Non-motion-corrected free-breathing data served as standard of reference in this study. Motion correction generally improved lesion visibility (3.19 ± 0.63) and noise ratings (2.95 ± 0.22) compared to uncorrected (2.81 ± 0.66 and 2.95 ± 0.22, respectively) or gated PET data (2.47 ± 0.93 and 1.30 ± 0.47, respectively). Furthermore, SUVs (mean and max) were compared for all methods to estimate their respective impact on the quantification. Deviations of SUVmax were smallest between the uncorrected and the MoCo lesion data (average increase of 9.1% of MoCo SUVs), while SUVmean agreed best for gated and MoCo reconstructions (MoCo SUVs increased by 1.2%). The studied method for MR-based respiratory motion correction of PET data combines increased lesion sharpness and improved lesion activity quantification with high signal-to-noise ratio in a clinical setting. In particular, the detection of small lesions in moving organs such as the lung and liver may thus be facilitated. These advantages justify the extension of the PET/MR imaging protocol by 5-10 minutes for motion correction.


Assuntos
Artefatos , Processamento de Imagem Assistida por Computador/métodos , Neoplasias Pulmonares/diagnóstico por imagem , Pulmão/diagnóstico por imagem , Imagem por Ressonância Magnética/métodos , Movimento (Física) , Imagem Multimodal/métodos , Tomografia por Emissão de Pósitrons/métodos , Mecânica Respiratória , Idoso , Idoso de 80 Anos ou mais , Feminino , Radioisótopos de Flúor , Fluordesoxiglucose F18 , Humanos , Aumento da Imagem/métodos , Pulmão/fisiologia , Masculino , Pessoa de Meia-Idade , Compostos Radiofarmacêuticos
17.
PLoS One ; 15(6): e0235130, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32579595

RESUMO

OBJECTIVES: Contrast-enhanced ultrasound (CEUS) enables the assessment of real-time renal microcirculation. This study investigated CEUS-driven parameters as hemodynamic predictors for renal outcomes in patients with acute kidney injury (AKI). METHODS: Forty-eight patients who were diagnosed with AKI were prospectively enrolled and underwent CEUS at the occurrence of AKI. Parameters measured were the wash-in slope (WIS), time to peak intensity, peak intensity (PI), area under the time-intensity curve (AUC), mean transit time (MTT), time for full width at half maximum, and rise time (RT). The predictive performance of the CEUS-driven parameters for Kidney Disease Improving Global Outcomes (KDIGO) AKI stage, initiation of renal replacement therapy (RRT), AKI recovery, and chronic kidney disease (CKD) progression was assessed. Receiver operating characteristic (ROC) analysis was performed to evaluate the diagnostic performance of CEUS. RESULTS: Cortical RT (Odds ratio [OR] = 1.21) predicted the KDIGO stage 3 AKI. Cortical MTT (OR = 1.07) and RT (OR = 1.20) predicted the initiation of RRT. Cortical WIS (OR = 76.23) and medullary PI (OR = 1.25) predicted AKI recovery. Medullary PI (OR = 0.78) and AUC (OR = 1.00) predicted CKD progression. The areas under the ROC curves showed reasonable performance for predicting the initiation of RRT and AKI recovery. The sensitivity and specificity of the quantitative CEUS parameters were 60-83% and 62-77%, respectively, with an area under the curve of 0.69-0.75. CONCLUSION: CEUS may be a supplemental tool in diagnosing the severity of AKI and predicting renal prognosis in patients with AKI.


Assuntos
Lesão Renal Aguda/diagnóstico , Meios de Contraste/química , Aumento da Imagem/métodos , Rim/diagnóstico por imagem , Ultrassonografia/métodos , Lesão Renal Aguda/terapia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Prognóstico , Estudos Prospectivos , Curva ROC , Insuficiência Renal Crônica/diagnóstico , Terapia de Substituição Renal/métodos
18.
Radiol Med ; 125(12): 1288-1300, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32415476

RESUMO

Magnetic resonance imaging (MRI) is particularly attractive for clinical application in perfusion imaging thanks to the absence of ionizing radiation and limited volumes of contrast agent (CA) necessary. Dynamic contrast-enhanced MRI (DCE-MRI) involves sequentially acquiring T1-weighted images through an organ of interest during the passage of a bolus administration of CA. It is a particularly flexible approach to perfusion imaging as the signal intensity time course allows not only rapid qualitative assessment, but also quantitative measures of intrinsic perfusion and permeability parameters. We examine aspects of the T1-weighted image series acquisition, CA administration, post-processing that constitute a DCE-MRI study in clinical practice, before considering some heuristics that may aid in interpreting the resulting contrast enhancement time series. While qualitative DCE-MRI has a well-established role in the diagnostic assessment of a range of tumours, and a central role in MR mammography, clinical use of quantitative DCE-MRI remains limited outside of clinical trials. The recent publication of proposals for standardized acquisition and analysis protocols for DCE-MRI by the Quantitative Imaging Biomarker Alliance may be an opportunity to consolidate and advance clinical practice.


Assuntos
Meios de Contraste/farmacocinética , Aumento da Imagem/métodos , Imagem por Ressonância Magnética/métodos , Neoplasias/diagnóstico por imagem , Permeabilidade Capilar/fisiologia , Meios de Contraste/administração & dosagem , Espaço Extracelular/diagnóstico por imagem , Espaço Extracelular/metabolismo , Humanos , Neoplasias/irrigação sanguínea , Imagem de Perfusão/métodos , Fluxo Sanguíneo Regional/fisiologia
19.
PLoS One ; 15(5): e0232583, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32392215

RESUMO

A modern color filter array (CFA) output is rendered into the final output image using a demosaicing algorithm. During this process, the rendered image is affected by optical and carrier cross talk of the CFA pattern and demosaicing algorithm. Although many CFA patterns have been proposed thus far, an image-quality (IQ) evaluation system capable of comprehensively evaluating the IQ of each CFA pattern has yet to be developed, although IQ evaluation items using local characteristics or specific domain have been created. Hence, we present an IQ metric system to evaluate the IQ performance of CFA patterns. The proposed CFA evaluation system includes proposed metrics such as the moiré robustness using the experimentally determined moiré starting point (MSP) and achromatic reproduction (AR) error, as well as existing metrics such as color accuracy using CIELAB, a color reproduction error using spatial CIELAB, structural information using the structure similarity, the image contrast based on MTF50, structural and color distortion using the mean deviation similarity index (MDSI), and perceptual similarity using Haar wavelet-based perceptual similarity index (HaarPSI). Through our experiment, we confirmed that the proposed CFA evaluation system can assess the IQ for an existing CFA. Moreover, the proposed system can be used to design or evaluate new CFAs by automatically checking the individual performance for the metrics used.


Assuntos
Algoritmos , Aumento da Imagem , Cor , Aumento da Imagem/instrumentação , Aumento da Imagem/métodos , Sistema Métrico , Fotografação/instrumentação , Fotografação/métodos
20.
AJR Am J Roentgenol ; 215(1): 206-214, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32374667

RESUMO

OBJECTIVE. The purpose of this article is to summarize current common techniques and indications for pediatric abdominopelvic MR angiography and strategies for optimizing them to achieve successful outcomes. We also discuss newer MR angiography techniques, including whole-body imaging and blood pool contrast agents, as well as various approaches to reducing the need for anesthesia in pediatric MRI. CONCLUSION. Pediatric body vascular imaging presents a unique set of challenges that require a tailored approach. Emerging pediatric abdominopelvic MR angiography techniques hold promise for continued improvement in pediatric body MR angiography.


Assuntos
Abdome/irrigação sanguínea , Abdome/diagnóstico por imagem , Angiografia por Ressonância Magnética/métodos , Doenças Vasculares/diagnóstico por imagem , Adolescente , Criança , Meios de Contraste , Humanos , Aumento da Imagem/métodos , Imagem Corporal Total
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