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1.
Medicine (Baltimore) ; 99(9): e19300, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32118747

RESUMO

To characterize the fractional amplitude of low-frequency fluctuation (fALFF) in drug-naïve first-episode female patients with anorexia nervosa (AN) using resting-state functional magnetic resonance imaging (rs-fMRI).Whole brain rs-fMRI data were collected from 7 drug-naïve first-episode female patients with DSM-5 AN and 14 age-matched healthy female controls. fALFF values were calculated and compared between the two groups using a two-sample t test. Correlation analysis between the fALFF values in the entire brain and body mass index (BMI) was performed.Compared with the healthy controls, increased fALFF values were observed in the AN patients in their right hippocampus and left superior frontal gyrus, while decreased fALFF values were observed in their left rectus and left middle occipital gyrus. Moreover, low BMI was significantly associated with decreased fALFF in the left inferior frontal gyrus but increased fALFF in the left calcarine. In particular, the z-standardized fALFF (zfALFF) value of the left rectus was positive associated with BMI.Our findings suggest that spontaneous brain activity in the frontal region, hippocampus and rectus, characterized by fALFF values, was altered in drug-naïve, first-episode female patients with AN.


Assuntos
Anorexia Nervosa/tratamento farmacológico , Imagem por Ressonância Magnética/normas , Adolescente , Adulto , Anorexia Nervosa/fisiopatologia , Anorexia Nervosa/psicologia , China , Feminino , Humanos , Imagem por Ressonância Magnética/métodos , Imagem por Ressonância Magnética/estatística & dados numéricos , Lobo Occipital/anormalidades , Lobo Occipital/anatomia & histologia , Córtex Pré-Frontal/anormalidades , Córtex Pré-Frontal/anatomia & histologia
2.
Can Assoc Radiol J ; 71(1): 83-91, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32062993

RESUMO

PURPOSE: Magnetic resonance imaging (MRI) is not beneficial in patients with joint pain and concomitant osteoarthritis (OA). We attempt to determine whether evaluation of OA via X-rays can reduce inappropriate MRI and computed tomography (CT) arthrogram use. In our jurisdiction, CT arthrograms are used as surrogate tests because of MRI wait times. MATERIALS AND METHODS: Our intervention required patients ≥55 years of age scheduled for outpatient MRI of the knee/hip/shoulder at an urban hospital to have X-rays (weight bearing when appropriate) from within 1 year. Red flags (ie, neoplasm, infection) were identified for which MRI would be indicated regardless. Through review of radiographs on picture archiving and communication system/digital media and use of the validated Kellgren-Lawrence (KL) OA scale, radiologists assessed the presence and degree of OA. A finding of significant OA (KL > 2) without red flags would preclude MRI. Monthly averages of MRI and CT arthrogram examinations were measured 33 months before and 23 months following introduction of the intervention. RESULTS: The proportion of protocoled MRI requisitions that were avoided was 21%. If extrapolated to the province of British Columbia, 2419 of 11 700 examinations could have been prevented in the past year. The average monthly number of knee/hip/shoulder MRI examinations as a percentage of total MRI examinations decreased from 4.9% to 4.3% (P < .02) following the intervention. The average monthly number of knee/hip/shoulder CT arthrogram examinations decreased from 20.6 to 12.1 (P < .0001). CONCLUSION: We were able to decrease the number of MRI and CT arthrogram examinations in patients ≥55 years of age with joint pain by implementing an evaluation for OA via recent X-ray imaging.


Assuntos
Artralgia/diagnóstico por imagem , Imagem por Ressonância Magnética/estatística & dados numéricos , Osteoartrite/diagnóstico por imagem , Idoso , Artrografia , Colúmbia Britânica , Tomada de Decisões , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Tomografia Computadorizada por Raios X , Listas de Espera
3.
Radiol Med ; 125(3): 272-279, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31784927

RESUMO

OBJECTIVE: The purpose of this study is to investigate the role of cervical radiography in the study of patients with vertigo and dizziness. PATIENTS: This is a retrospective single-institution case series study of 493 patients suffering from vertigo and dizziness who were referred (from January 2011 to December 2012) to the hospital to study those symptoms. METHODS: We studied cervical radiographies, CT and MRI of the cervical spine made in the sample and the radiological findings. We analyzed demographic characteristics, presence of psychiatric pathology and emergency assistance due to vertigo in patients who have undergone cervical study. RESULTS: A total of 57% of patients had cervical radiography made; this was more frequent in women, Spanish people, with psychiatric pathology and who have gone to the emergency department for vertigo (p < 0.05). Degenerative changes were found in 74.1% of the patients with radiography made, more frequently at an older age, osteophytes in 49.5% and abnormal cervical lordosis in 37.1%. CONCLUSIONS: There are sociodemographic factors that influence in the request for cervical radiographs in patients with vertigo and dizziness. Given the suspicion of cervical vertigo, we do not consider that the findings in the radiographs help in the diagnosis. In our opinion, an excessive use of cervical radiography is made in patients with vertigo and dizziness.


Assuntos
Vértebras Cervicais/diagnóstico por imagem , Tontura , Imagem por Ressonância Magnética/estatística & dados numéricos , Tomografia Computadorizada por Raios X/estatística & dados numéricos , Vertigem , Análise de Variância , Distribuição de Qui-Quadrado , Tontura/epidemiologia , Emergências , Serviço Hospitalar de Emergência/estatística & dados numéricos , Feminino , Humanos , Masculino , Sobremedicalização/estatística & dados numéricos , Pessoa de Meia-Idade , Estudos Retrospectivos , Distribuição por Sexo , Espanha/epidemiologia , Vertigem/epidemiologia
4.
Medicine (Baltimore) ; 98(50): e18324, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31852123

RESUMO

BACKGROUND: Although many machine learning algorithms have been developed to detect anterior cruciate ligament (ACL) injury based on magnetic resonance imaging (MRI), the performance of different algorithms required further investigation. The objectives of this current systematic review are to evaluate the diagnostic accuracy of machine-learning-assisted detection for ACL injury based on MRI and find the current best algorithm. METHOD: We will conduct a comprehensive database search for clinical diagnostic tests in PubMed, EMBASE, Cochrane Library, and Web of science without restrictions on publication status and language. The reference lists of the included articles will also be checked to identify additional studies for potential inclusion. Two reviewers will independently review all literature for inclusion and assess their methodological quality using Quality Assessment of Diagnostic Accuracy Studies version 2. Clinical diagnostic tests exploring the efficacy of machine-learning-assisted system for detecting ACL injury based on MRI will be considered for inclusion. Another 2 reviewers will independently extract data from eligible studies based on a pre-designed standardized form. Any disagreements will be resolved by consensus. RevMan 5.3 and Stata SE 12.0 software will be used for data synthesis. If appropriate, we will calculate the summary sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio of machine-learning-assisted diagnosis system for ACL injury detection. A hierarchical summary receiver operating characteristic (HSROC) curve will also be plotted, and the area under the ROC curve (AUC) is going to calculated using the bivariate model. If the pooling of results is considered inappropriate, we will present and describe our findings in diagrams and tables and describe them narratively. RESULT: This is the first systematic assessment of machine learning system for the detection of ACL injury based on MRI. We predict it will provide highquality synthesis of existing evidence for the diagnostic accuracy of machine-learning-assisted detection for ACL injury and a relatively comprehensive reference for clinical practice and development of interdisciplinary field of artificial intelligence and medicine. CONCLUSION: This protocol outlined the significance and methodologically details of a systematic review of machine-learning-assisted detection for ACL injury based on MRI. The ongoing systematic review will provide high-quality synthesis of current evidence of machine learning system for detecting ACL injury. REGISTRATION: The meta-analysis has been prospectively registered in PROSPERO (CRD42019136581).


Assuntos
Lesões do Ligamento Cruzado Anterior/diagnóstico por imagem , Diagnóstico por Computador/estatística & dados numéricos , Aprendizado de Máquina , Imagem por Ressonância Magnética/estatística & dados numéricos , Diagnóstico por Computador/métodos , Humanos , Imagem por Ressonância Magnética/métodos , Metanálise como Assunto , Curva ROC , Projetos de Pesquisa , Sensibilidade e Especificidade , Revisão Sistemática como Assunto
5.
PLoS Comput Biol ; 15(12): e1006997, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31856159

RESUMO

Magnetic resonance tomography typically applies the Fourier transform to k-space signals repeatedly acquired from a frequency encoded spatial region of interest, therefore requiring a stationary object during scanning. Any movement of the object results in phase errors in the recorded signal, leading to deformed images, phantoms, and artifacts, since the encoded information does not originate from the intended region of the object. However, if the type and magnitude of movement is known instantaneously, the scanner or the reconstruction algorithm could be adjusted to compensate for the movement, directly allowing high quality imaging with non-stationary objects. This would be an enormous boon to studies that tie cell metabolomics to spontaneous organism behaviour, eliminating the stress otherwise necessitated by restraining measures such as anesthesia or clamping. In the present theoretical study, we use a phantom of the animal model C. elegans to examine the feasibility to automatically predict its movement and position, and to evaluate the impact of movement prediction, within a sufficiently long time horizon, on image reconstruction. For this purpose, we use automated image processing to annotate body parts in freely moving C. elegans, and predict their path of movement. We further introduce an MRI simulation platform based on bright field videos of the moving worm, combined with a stack of high resolution transmission electron microscope (TEM) slice images as virtual high resolution phantoms. A phantom provides an indication of the spatial distribution of signal-generating nuclei on a particular imaging slice. We show that adjustment of the scanning to the predicted movements strongly reduces distortions in the resulting image, opening the door for implementation in a high-resolution NMR scanner.


Assuntos
Imagem por Ressonância Magnética/métodos , Algoritmos , Animais , Caenorhabditis elegans/anatomia & histologia , Caenorhabditis elegans/fisiologia , Biologia Computacional , Simulação por Computador , Estudos de Viabilidade , Humanos , Processamento de Imagem Assistida por Computador/métodos , Processamento de Imagem Assistida por Computador/estatística & dados numéricos , Imagem por Ressonância Magnética/estatística & dados numéricos , Modelos Biológicos , Movimento (Física) , Movimento , Imagens de Fantasmas
6.
Medicine (Baltimore) ; 98(48): e18101, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31770231

RESUMO

This retrospective study aimed to improve the diagnostic accuracy of breast lymphoma (BL) by analyzing the findings of BL on mammography and magnetic resonance imaging (MRI).Fifteen patients with breast lymphoma (BL, Primary/Secondary: 13/2) were confirmed by pathology. The imaging findings of those patients were analyzed by 2 senior radiologists.BL commonly showed significant enhancement with penetrating vessels and septation in masses on dynamic contrast-enhanced MRI (DCE-MRI). Diffusion limitation of BL is more pronounced than breast cancer on diffusion weighted imaging.The study suggests that the penetrating vessels and diffusion restriction of lesions are helpful for the diagnosis and differential diagnosis of BL.


Assuntos
Neoplasias da Mama/diagnóstico por imagem , Aumento da Imagem/métodos , Linfoma/diagnóstico por imagem , Imagem por Ressonância Magnética/estatística & dados numéricos , Mamografia/estatística & dados numéricos , Adulto , Meios de Contraste , Diagnóstico Diferencial , Imagem de Difusão por Ressonância Magnética/métodos , Imagem de Difusão por Ressonância Magnética/estatística & dados numéricos , Feminino , Humanos , Imagem por Ressonância Magnética/métodos , Mamografia/métodos , Pessoa de Meia-Idade , Estudos Retrospectivos
7.
Curr Med Sci ; 39(5): 831-835, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31612404

RESUMO

Recent researches have found that 7 Tesla SWI can detect the alteration of substantia nigra hyperintensity in Parkinson's disease (PD), multiple system atrophy (MSA), and progressive supranuclear palsy (PSP). The aim of this study was to investigate whether 3 Tesla SWI (3T SWI) can visualize anatomical alterations occurring in a hyperintense structure of the substantia nigra in PD and vascular parkinsonism (VP), and whether the evaluation of abnormal signal can be used as a factor in the differential diagnosis of PD and VP. Using 3 Tesla MRI, we evaluated 38 healthy subjects, 33 patients with PD and 34 patients with VP. Two blinded readers independently assessed the images. We found that the dorsolateral nigral hyperintensity was absent in 31 of 33 patients with PD and 15 of 34 patients with VP. The dorsolateral nigral hyperintensity was present in 19 of 34 patients with VP and 35 of 38 healthy controls. Group comparisons of absence of dorsolateral nigral hyperintensity revealed significant differences between the patients with PD and those with VP (P<0.001). The sensitivity of SWI for PD was 93.9% and the specificity was 92.1%. Visual assessment of dorsolateral nigral hyperintensity on high-field SWI scans may serve as a new simple diagnostic imaging marker for PD. And our study results indicate that 3T SWI can be used as a tool to identify PD and VP.


Assuntos
Demência por Múltiplos Infartos/diagnóstico por imagem , Imagem por Ressonância Magnética/estatística & dados numéricos , Doença de Parkinson/diagnóstico por imagem , Substância Negra/diagnóstico por imagem , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/análise , Estudos de Casos e Controles , Demência por Múltiplos Infartos/patologia , Diagnóstico Diferencial , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Doença de Parkinson/patologia , Sensibilidade e Especificidade , Substância Negra/irrigação sanguínea , Substância Negra/patologia
8.
Medicine (Baltimore) ; 98(39): e17187, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31574825

RESUMO

BACKGROUND: Surgical resection is the recommended procedure for colorectal cancer (CRC), but majority of the patients were diagnosed with advanced or metastatic CRC. Currently, there were inconsistent results about the diagnostic value of magnetic resonance colonography (MRC) and computed tomography colonography (CTC) in early CRC diagnosis. Our study conducted this meta-analysis to investigate the diagnostic value of MRC and CTC for CRC surveillance. METHODS: A comprehensive literature search was conducted in PubMed, Embase, and the Cochrane library to select relevant studies. The summary sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and the area under the receiver operating characteristic curves (AUC) were calculated to evaluate the diagnostic value of MRC and CTC, respectively. RESULT: Twenty-five studies including 2985 individuals were selected in the final analysis. Eight studies evaluated the diagnostic value of MRC, and 17 studies assessed CTC. The summary sensitivity, specificity, PLR, NLR, DOR, and AUC in MRC for early detection of CRC were 0.98 (95% confidence interval, CI: 0.80-1.00), 0.94 (95% CI: 0.85-0.97), 15.48 (95% CI: 6.30-38.04), 0.02 (95% CI: 0.00-0.25), 115.09 (95% CI: 15.37-862.01), and 0.98 (95% CI: 0.97-0.99), respectively. In addition, the sensitivity, specificity, PLR, NLR, DOR, and AUC of CTC for diagnosing CRC were 0.97 (95% CI: 0.88-0.99), 0.99 (95% CI: 0.99-1.00), 154.11 (95% CI: 67.81-350.22), 0.03 (95% CI: 0.01-0.13), 642.51 (95% CI: 145.05-2846.02), and 1.00 (95% CI: 0.99-1.00). No significant differences were found between MRC and CTC for DOR in all the subsets. CONCLUSION: The findings of meta-analysis indicated that MRC and CTC have higher diagnostic values for early CRC diagnosis. However, the DOR for diagnosing CRC between MRC and CTC showed no significance.


Assuntos
Colonografia Tomográfica Computadorizada/estatística & dados numéricos , Neoplasias Colorretais/diagnóstico por imagem , Detecção Precoce de Câncer/estatística & dados numéricos , Imagem por Ressonância Magnética/estatística & dados numéricos , Idoso , Colonografia Tomográfica Computadorizada/métodos , Detecção Precoce de Câncer/métodos , Feminino , Humanos , Imagem por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Razão de Chances , Sensibilidade e Especificidade
9.
Pediatrics ; 144(4)2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31533974

RESUMO

BACKGROUND: Computed tomography (CT) is commonly used for children when there is concern for traumatic brain injury (TBI) and is a significant source of ionizing radiation. Our objective was to determine the feasibility and accuracy of fast MRI (motion-tolerant MRI sequences performed without sedation) in young children. METHODS: In this prospective cohort study, we attempted fast MRI in children <6 years old who had head CT performed and were seen in the emergency department of a single, level 1 pediatric trauma center. Fast MRI sequences included 3T axial and sagittal T2 single-shot turbo spin echo, axial T1 turbo field echo, axial fluid-attenuated inversion recovery, axial gradient echo, and axial diffusion-weighted single-shot turbo spin echo planar imaging. Feasibility was assessed by completion rate and imaging time. Fast MRI accuracy was measured against CT findings of TBI, including skull fracture, intracranial hemorrhage, or parenchymal injury. RESULTS: Among 299 participants, fast MRI was available and attempted in 225 (75%) and completed in 223 (99%). Median imaging time was 59 seconds (interquartile range 52-78) for CT and 365 seconds (interquartile range 340-392) for fast MRI. TBI was identified by CT in 111 (50%) participants, including 81 skull fractures, 27 subdural hematomas, 24 subarachnoid hemorrhages, and 35 other injuries. Fast MRI identified TBI in 103 of these (sensitivity 92.8%; 95% confidence interval 86.3-96.8), missing 6 participants with isolated skull fractures and 2 with subarachnoid hemorrhage. CONCLUSIONS: Fast MRI is feasible and accurate relative to CT in clinically stable children with concern for TBI.


Assuntos
Lesões Encefálicas Traumáticas/diagnóstico por imagem , Imagem por Ressonância Magnética/métodos , Tomografia Computadorizada por Raios X/métodos , Pré-Escolar , Estudos de Viabilidade , Feminino , Hematoma Subdural/diagnóstico por imagem , Humanos , Lactente , Recém-Nascido , Hemorragias Intracranianas/diagnóstico por imagem , Imagem por Ressonância Magnética/estatística & dados numéricos , Masculino , Estudos Prospectivos , Exposição à Radiação/prevenção & controle , Reprodutibilidade dos Testes , Fraturas Cranianas/diagnóstico por imagem , Fatores de Tempo , Tomografia Computadorizada por Raios X/estatística & dados numéricos , Centros de Traumatologia/estatística & dados numéricos
10.
Transplant Proc ; 51(7): 2391-2396, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31474296

RESUMO

OBJECTIVE: To evaluate the diagnostic accuracy of Intravoxel Incoherent Motion (IVIM) parameters for assessment of tumor response after locoregional treatment (LRT) of hepatocellular carcinoma (HCC). METHODS: Fifteen patients with HCC who had undergone LRTs (11 transarterial radioembolization, 4 transarterial chemoembolization) were included. In addition to routine upper abdominal magnetic resonance imaging sequences, IVIM with 16 different b values and conventional diffusion weighted imaging with 3 different b factors were obtained immediately before and 8 weeks after LRTs. Magnetic resonance imaging response was evaluated according to modified Response Evaluation Criteria in Solid Tumors (mRECIST) and HCCs were categorized into 2 subgroups, responders and nonresponders. Quantitatively, the number of diffusion-changes were calculated with apparent diffusion coefficient (ADC) and IVIM parameters, including mean D (true diffusion coefficient), pseudo-diffusion coefficient associated with blood flow, and f (perfusion fraction) values. Subsequently, the pre- and post-treatment parameters were compared using the Mann-Whitney U test. RESULTS: Considering all HCCs, a significant decrease was observed according to mRECIST criteria (-38.43 ± 16.49). The ADC and D values after LRTs were significantly higher than those of the preceding ones. The f values after LRTs were significantly lower than those of pre-treatment. In the responders group, ADC and D values were significantly increased and f values were significantly decreased after LRTs. No difference of statistical significance was achieved in the nonresponders group. CONCLUSIONS: ADC values and IVIM parameters appear to reflect the response of LRTs as effectively as those of mRECIST. This promises new horizons in the management of pretransplant patients, especially in renal insufficiency clinical settings, owing to the elimination of contrast media administration.


Assuntos
Carcinoma Hepatocelular/diagnóstico por imagem , Neoplasias Hepáticas/diagnóstico por imagem , Transplante de Fígado , Imagem por Ressonância Magnética/estatística & dados numéricos , Cuidados Pré-Operatórios/métodos , Adulto , Idoso , Braquiterapia/estatística & dados numéricos , Carcinoma Hepatocelular/patologia , Carcinoma Hepatocelular/terapia , Quimioembolização Terapêutica/estatística & dados numéricos , Meios de Contraste , Imagem de Difusão por Ressonância Magnética/métodos , Imagem de Difusão por Ressonância Magnética/estatística & dados numéricos , Feminino , Humanos , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas/terapia , Imagem por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Movimento (Física) , Período Pré-Operatório , Resultado do Tratamento
11.
Pediatrics ; 144(4)2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31488696

RESUMO

BACKGROUND: In May 2016, the American Academy of Pediatrics published a clinical practice guideline for brief resolved unexplained events (BRUEs). We evaluated for changes in the management of BRUE after guideline publication. METHODS: Using a pediatric multicenter administrative database, we compared rates of admission, testing, revisits, and diagnoses in patients diagnosed with a BRUE or apparent life-threatening event (ALTE) during 2017 with rates of admission, testing, revisits, and diagnoses in patients diagnosed with ALTE during 2015. We used interrupted time series analysis to test if the guideline was associated with changes in admission rate for all patients with ALTE or BRUE between 2015 and 2017. We stratified analyses by age (0-60 and 61-365 days). RESULTS: A total of 9501 patients were included (5608 in 2015 and 3893 in 2017). The admission rate decreased by 5.7% (95% confidence interval, 3.8% to 7.5%) for infants 0 to 60 days and by 18.0% (95% confidence interval, 15.3% to 20.7%) for infants 61 to 365 days from 2015 to 2017. Patients in 2017 had lower rates of EEG, brain MRI, chest radiography, laboratory testing, and urinalyses compared with patients in 2015. In the interrupted time series analysis model (n = 13 977), guideline publication was associated with decreasing admission rates (0.2% per week) for infants 61 to 365 days (P < .001). CONCLUSIONS: Compared with patients evaluated in 2015, patients with BRUE or ALTE in 2017 have lower rate of admissions and testing. Findings may be due to changes in the definition of BRUE and guideline recommendations.


Assuntos
Hospitalização/estatística & dados numéricos , Sintomas Inexplicáveis , Guias de Prática Clínica como Assunto , Intervalos de Confiança , Eletroencefalografia/estatística & dados numéricos , Humanos , Lactente , Recém-Nascido , Análise de Séries Temporais Interrompida , Imagem por Ressonância Magnética/estatística & dados numéricos , Radiografia Torácica/estatística & dados numéricos
12.
JAMA ; 322(9): 843-856, 2019 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-31479136

RESUMO

Importance: Medical imaging increased rapidly from 2000 to 2006, but trends in recent years have not been analyzed. Objective: To evaluate recent trends in medical imaging. Design, Setting, and Participants: Retrospective cohort study of patterns of medical imaging between 2000 and 2016 among 16 million to 21 million patients enrolled annually in 7 US integrated and mixed-model insurance health care systems and for individuals receiving care in Ontario, Canada. Exposures: Calendar year and country (United States vs Canada). Main Outcomes and Measures: Use of computed tomography (CT), magnetic resonance imaging (MRI), ultrasound, and nuclear medicine imaging. Annual and relative imaging rates by imaging modality, country, and age (children [<18 years], adults [18-64 years], and older adults [≥65 years]). Results: Overall, 135 774 532 imaging examinations were included; 5 439 874 (4%) in children, 89 635 312 (66%) in adults, and 40 699 346 (30%) in older adults. Among adults and older adults, imaging rates were significantly higher in 2016 vs 2000 for all imaging modalities other than nuclear medicine. For example, among older adults, CT imaging rates were 428 per 1000 person-years in 2016 vs 204 per 1000 in 2000 in US health care systems and 409 per 1000 vs 161 per 1000 in Ontario; for MRI, 139 per 1000 vs 62 per 1000 in the United States and 89 per 1000 vs 13 per 1000 in Ontario; and for ultrasound, 495 per 1000 vs 324 per 1000 in the United States and 580 per 1000 vs 332 per 1000 in Ontario. Annual growth in imaging rates among US adults and older adults slowed over time for CT (from an 11.6% annual percentage increase among adults and 9.5% among older adults in 2000-2006 to 3.7% among adults in 2013-2016 and 5.2% among older adults in 2014-2016) and for MRI (from 11.4% in 2000-2004 in adults and 11.3% in 2000-2005 in older adults to 1.3% in 2007-2016 in adults and 2.2% in 2005-2016 in older adults). Patterns in Ontario were similar. Among children, annual growth for CT stabilized or declined (United States: from 10.1% in 2000-2005 to 0.8% in 2013-2016; Ontario: from 3.3% in 2000-2006 to -5.3% in 2006-2016), but patterns for MRI were similar to adults. Changes in annual growth in ultrasound were smaller among adults and children in the United States and Ontario compared with CT and MRI. Nuclear medicine imaging declined in adults and children after 2006. Conclusions and Relevance: From 2000 to 2016 in 7 US integrated and mixed-model health care systems and in Ontario, rates of CT and MRI use continued to increase among adults, but at a slower pace in more recent years. In children, imaging rates continued to increase except for CT, which stabilized or declined in more recent periods. Whether the observed imaging utilization was appropriate or was associated with improved patient outcomes is unknown.


Assuntos
Diagnóstico por Imagem/tendências , Abdome/diagnóstico por imagem , Adolescente , Adulto , Idoso , Criança , Diagnóstico por Imagem/estatística & dados numéricos , Cabeça/diagnóstico por imagem , Humanos , Imagem por Ressonância Magnética/estatística & dados numéricos , Imagem por Ressonância Magnética/tendências , Pessoa de Meia-Idade , Ontário , Cintilografia/estatística & dados numéricos , Cintilografia/tendências , Coluna Vertebral/diagnóstico por imagem , Tórax/diagnóstico por imagem , Tomografia Computadorizada por Raios X/estatística & dados numéricos , Tomografia Computadorizada por Raios X/tendências , Ultrassonografia/estatística & dados numéricos , Ultrassonografia/tendências , Estados Unidos , Adulto Jovem
13.
Radiologe ; 59(9): 804-811, 2019 Sep.
Artigo em Alemão | MEDLINE | ID: mdl-31414150

RESUMO

CLINICAL PROBLEM: Colorectal metastases are the most common malignant liver lesions. Imaging of the liver in patients with colorectal carcinoma is performed for early detection of liver metastases (CRLM) at the time of initial tumor diagnosis, for monitoring and follow-up in order to exclude or diagnose metachronous metastases. STANDARD RADIOLOGICAL METHODS: Radiological imaging includes primarily multislice computed tomography (CT) and magnetic resonance imaging (MRI), which play an important role regarding therapeutic management and assessment of prognosis. PERFORMANCE, ACHIEVEMENTS: Contrast-enhanced CT is broadly available and allows for rapid image acquisition including the possibility for complete tumor staging. MRI, on the other hand, is characterized by very good soft tissue contrast and has-especially with the use of diffusion-weighted imaging and administration of liver-specific contrast agents-the highest sensitivity for detection of metastases smaller than 1 cm. PRACTICAL RECOMMENDATIONS: The choice of imaging in daily routine is often dependent on availability and clinical question. Frequently, e.g. for assessment of resectability (extent of metastases, anatomic relation of lesions to critical structures), both modalities may be implemented in combination.


Assuntos
Neoplasias Colorretais , Neoplasias Hepáticas , Neoplasias Colorretais/diagnóstico por imagem , Humanos , Neoplasias Hepáticas/diagnóstico , Neoplasias Hepáticas/secundário , Imagem por Ressonância Magnética/estatística & dados numéricos , Tomografia Computadorizada por Raios X
15.
Comput Methods Programs Biomed ; 179: 104976, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31443856

RESUMO

BACKGROUND AND OBJECTIVE: There has been growing interest in using functional connectivity patterns, determined from fMRI data to characterize groups of individuals exhibiting common traits. However, the present challenge lies in efficient and accurate identification of distinct patterns observed consistently across multiple subjects. Existing approaches either impose strong assumptions, require aligning images before processing, or require data-intensive machine learning algorithms with manually labeled training datasets. In this paper, we propose a more principled and flexible approach to address this. METHODS: Our approach redefines the problem of estimating the group-representative functional network as an image segmentation problem. After employing an improved clustering-based ICA scheme to pre-process the dataset of individual functional network images, we use a maximum a posteriori-Markov random field (MAP-MRF) framework to solve the image segmentation problem. In this framework, we propose a probabilistic model of the individual pixels of the fMRI data, with the model involving a latent group-representative functional network image. Given an observed dataset, we apply a novel and efficient variational Bayes algorithm to recover the associated latent group image. Our methodology seeks to overcome limitations in more traditional schemes by exploiting spatial relationships underlying the connectivity maps and accounting for uncertainty in the estimation process. RESULTS: We validate our approach using synthetic, simulated and real data. First, we generate datasets from the proposed forward model with subject-specific binary masking and measurement noise, as well as from a variant of the model without measurement noise. We use both datasets to evaluate our model, along with two algorithms: coordinate-ascent algorithm and variational Bayes algorithm. We conclude that our proposed model with variational Bayes outperforms other competitors, even under model-misspecification. Using variational Bayes offers a significant improvement in performance, with almost no additional computational overhead. We next test our approach on simulated fMRI data. We show our approach is robust to initialization and can recover a solution close to the ground truth. Finally, we apply our proposed methodology along with baselines to a real dataset of fMRI recordings of individuals from two groups, a control group and a group suffering from depression, with recordings made while individuals were subjected to musical stimuli. Our methodology is able to identify group differences that are less clear under competing methods. CONCLUSIONS: Our model-based approach demonstrates the advantage of probabilistic models and modern algorithms that account for uncertainty in accurate identification of group-representative connectivity maps. The variational Bayes methodology yields highly accurate results without increasing the computational load compared to traditional methods. In addition, it is robust to model misspecification, and increases the ability to avoid local optima in the solution.


Assuntos
Conectoma/estatística & dados numéricos , Neuroimagem Funcional/estatística & dados numéricos , Imagem por Ressonância Magnética/estatística & dados numéricos , Algoritmos , Teorema de Bayes , Análise por Conglomerados , Biologia Computacional , Simulação por Computador , Depressão/diagnóstico por imagem , Humanos , Interpretação de Imagem Assistida por Computador/estatística & dados numéricos , Processamento de Imagem Assistida por Computador/estatística & dados numéricos , Aprendizado de Máquina , Cadeias de Markov , Modelos Estatísticos
16.
Comput Methods Programs Biomed ; 179: 104993, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31443866

RESUMO

Twin-to-twin transfusion syndrome (TTTS) is a serious condition that may occur in pregnancies when two or more fetuses share the same placenta. It is characterized by abnormal vascular connections in the placenta that cause blood to flow unevenly between the babies. If left untreated, perinatal mortality occurs in 90% of cases, whilst neurological injuries are still present in TTTS survivors. Minimally invasive fetoscopic laser surgery is the standard and optimal treatment for this condition, but is technically challenging and can lead to complications. Acquiring and maintaining the required surgical skills need consistent practice, and a steep learning curve. An accurate preoperative planning is thus vital for complex TTTS cases. To this end, we propose the first TTTS fetal surgery planning and simulation platform. The soft tissue of the mother, the uterus, the umbilical cords, the placenta and its vascular tree are segmented and registered automatically from magnetic resonance imaging and 3D ultrasound using computer vision and deep learning techniques. The proposed state-of-the-art technology is integrated into a flexible C++ and MITK-based application to provide a full exploration of the intrauterine environment by simulating the fetoscope camera as well as the laser ablation, determining the correct entry point, training doctors' movements and trajectory ahead of operation, which allows improving upon current practice. A comprehensive usability study is reported. Experienced surgeons rated highly our TTTS planner and simulator, thus being a potential tool to be implemented in real and complex TTTS surgeries.


Assuntos
Transfusão Feto-Fetal/cirurgia , Fetoscopia/métodos , Modelos Anatômicos , Algoritmos , Gráficos por Computador , Simulação por Computador , Feminino , Transfusão Feto-Fetal/diagnóstico por imagem , Fetoscopia/estatística & dados numéricos , Humanos , Imagem Tridimensional , Recém-Nascido , Terapia a Laser/métodos , Terapia a Laser/estatística & dados numéricos , Imagem por Ressonância Magnética/estatística & dados numéricos , Modelagem Computacional Específica para o Paciente/estatística & dados numéricos , Placenta/diagnóstico por imagem , Gravidez , Interface Usuário-Computador , Útero/diagnóstico por imagem
17.
Comput Methods Programs Biomed ; 179: 104994, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31443867

RESUMO

BACKGROUND AND OBJECTIVE: Patients with mood disorders are known to have an emotion recognition deficit in facial emotion processing. Emotion perception involves two systems of cognitive and affective processes associated with brain activation in the fusiform gyrus and prefrontal cortices. To overcome the limitations of existing emotion perception tests, we designed an emotion perception index to assess the individuals' mood status. METHODS: We selected 66 emotional faces (22 pleasant, 22 unpleasant, and 22 neutral) for the emotion perception test and recruited 40 healthy participants to verify the test. The participants completed a demographic data questionnaire and were administered the Beck Depressive Inventory (BDI). They were also scanned to assess the brain functional connectivity (FC) between seeds of the fusiform gyrus and other brain regions using resting-state functional magnetic resonance imaging (rs-fMRI). After rs-fMRI scanning, the participants were administered the emotion perception test on a computer. RESULTS: In response to 108 questions regarding emotional face differentiation, the study group showed an average correct-answer rate of 90.7 ±â€¯6.4% and a mean reaction time of 1.4 ±â€¯0.4 s. We created an emotion perception index from the calculation of correct rate, number of correct responses, and reaction time in response to 108 questions; the mean of the emotion perception index in the study group was 3.8 ±â€¯0.2. The emotion perception index was positively correlated with the BDI scores (r = 0.4, p = 0.01); further, it was positively correlated with the FC from the fusiform gyrus to the left superior frontal gyrus (FDRq < 0.01), left medial frontal gyrus (FDRq < 0.01), left frontal precentral gyrus (FDRq = 0.02), left insula (FDRq < 0.01), and left occipital cuneus (FDRq = 0.01). The FC from the fusiform gyrus to the left insula was positively correlated with the BDI scores (r = 0.59, p < 0.001). CONCLUSIONS: The emotion perception index designed in this study may correctly indicate the mood status of individuals. In addition, the emotion perception test was associated with brain FC from the fusiform gyrus to the frontal and insular cortices.


Assuntos
Emoções/fisiologia , Neuroimagem Funcional/métodos , Imagem por Ressonância Magnética/métodos , Percepção/fisiologia , Adulto , Encéfalo/diagnóstico por imagem , Conectoma/métodos , Conectoma/estatística & dados numéricos , Expressão Facial , Feminino , Neuroimagem Funcional/estatística & dados numéricos , Voluntários Saudáveis , Humanos , Imagem por Ressonância Magnética/estatística & dados numéricos , Masculino , Transtornos do Humor/diagnóstico por imagem , Transtornos do Humor/psicologia , Córtex Pré-Frontal/diagnóstico por imagem , Lobo Temporal/diagnóstico por imagem , Adulto Jovem
18.
PLoS Comput Biol ; 15(8): e1007263, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31433810

RESUMO

A major tenet in theoretical neuroscience is that cognitive and behavioral processes are ultimately implemented in terms of the neural system dynamics. Accordingly, a major aim for the analysis of neurophysiological measurements should lie in the identification of the computational dynamics underlying task processing. Here we advance a state space model (SSM) based on generative piecewise-linear recurrent neural networks (PLRNN) to assess dynamics from neuroimaging data. In contrast to many other nonlinear time series models which have been proposed for reconstructing latent dynamics, our model is easily interpretable in neural terms, amenable to systematic dynamical systems analysis of the resulting set of equations, and can straightforwardly be transformed into an equivalent continuous-time dynamical system. The major contributions of this paper are the introduction of a new observation model suitable for functional magnetic resonance imaging (fMRI) coupled to the latent PLRNN, an efficient stepwise training procedure that forces the latent model to capture the 'true' underlying dynamics rather than just fitting (or predicting) the observations, and of an empirical measure based on the Kullback-Leibler divergence to evaluate from empirical time series how well this goal of approximating the underlying dynamics has been achieved. We validate and illustrate the power of our approach on simulated 'ground-truth' dynamical systems as well as on experimental fMRI time series, and demonstrate that the learnt dynamics harbors task-related nonlinear structure that a linear dynamical model fails to capture. Given that fMRI is one of the most common techniques for measuring brain activity non-invasively in human subjects, this approach may provide a novel step toward analyzing aberrant (nonlinear) dynamics for clinical assessment or neuroscientific research.


Assuntos
Imagem por Ressonância Magnética/estatística & dados numéricos , Modelos Neurológicos , Rede Nervosa/fisiologia , Algoritmos , Encéfalo/diagnóstico por imagem , Encéfalo/fisiologia , Biologia Computacional , Neuroimagem Funcional/estatística & dados numéricos , Humanos , Dinâmica não Linear , Análise de Sistemas
19.
Br J Neurosurg ; 0(0): 1-11, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31407596

RESUMO

Purpose: Cauda equina syndrome (CES) is a spinal emergency with clinical symptoms and signs that have low diagnostic accuracy. National guidelines in the United Kingdom (UK) state that all patients should undergo an MRI prior to referral to specialist spinal units and surgery should be performed at the earliest opportunity. We aimed to evaluate the current practice of investigating and treating suspected CES in the UK. Materials and Methods: A retrospective, multicentre observational study of the investigation and management of patients with suspected CES was conducted across the UK, including all patients referred to a spinal unit over 6 months between 1st October 2016 and 31st March 2017. Results: A total of 28 UK spinal units submitted data on 4441 referrals. Over half of referrals were made without any previous imaging (n = 2572, 57.9%). Of all referrals, 695 underwent surgical decompression (15.6%). The majority of referrals were made out-of-hours (n = 2229/3517, 63.4%). Patient location and pre-referral imaging were not associated with time intervals from symptom onset or presentation to decompression. Patients investigated outside of the spinal unit experienced longer time intervals from referral to undergoing the MRI scan. Conclusions: This is the largest known study of the investigation and management of suspected CES. We found that the majority of referrals were made without adequate investigations. Most patients were referred out-of-hours and many were transferred for an MRI without subsequently requiring surgery. Adherence to guidelines would reduce the number of referrals to spinal services by 72% and reduce the number of patient transfers by 79%.


Assuntos
Síndrome da Cauda Equina/diagnóstico , Encaminhamento e Consulta/estatística & dados numéricos , Adulto , Síndrome da Cauda Equina/cirurgia , Procedimentos Clínicos , Descompressão Cirúrgica/estatística & dados numéricos , Tratamento de Emergência , Utilização de Instalações e Serviços , Feminino , Humanos , Imagem por Ressonância Magnética/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade , Procedimentos Neurocirúrgicos/estatística & dados numéricos , Transferência de Pacientes/estatística & dados numéricos , Utilização de Procedimentos e Técnicas , Estudos Retrospectivos , Coluna Vertebral/cirurgia , Reino Unido
20.
Medicine (Baltimore) ; 98(33): e16608, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31415354

RESUMO

The utility of multimodality molecular imaging for predicting treatment response and survival of patients with hypopharyngeal carcinoma remains unclear. Here, we sought to investigate whether the combination of different molecular imaging parameters may improve outcome prediction in this patient group.Patients with pathologically proven hypopharyngeal carcinoma scheduled to undergo chemoradiotherapy (CRT) were deemed eligible. Besides clinical data, parameters obtained from pretreatment 2-deoxy-2-[fluorine-18]fluoro-D-glucose positron emission tomography/computed tomography (F-FDG PET/CT), dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI), and diffusion-weighted MRI were analyzed in relation to treatment response, recurrence-free survival (RFS), and overall survival (OS).A total of 61 patients with advanced-stage disease were examined. After CRT, 36% of the patients did not achieve a complete response. Total lesion glycolysis (TLG) and texture feature entropy were found to predict treatment response. The transfer constant (K), TLG, and entropy were associated with RFS, whereas K, blood plasma volume (Vp), standardized uptake value (SUV), and entropy were predictors of OS. Different scoring systems based on the sum of PET- or MRI-derived prognosticators enabled patient stratification into distinct prognostic groups (P <.0001). The complete response rate of patients with a score of 2 was significantly lower than those of patients with a score 1 or 0 (14.7% vs 58.9% vs 75.7%, respectively, P = .007, respectively). The combination of PET- and DCE-MRI-derived independent risk factors allowed a better survival stratification than the TNM staging system (P <.0001 vs .691, respectively).Texture features on F-FDG PET/CT and DCE-MRI are clinically useful to predict treatment response and survival in patients with hypopharyngeal carcinoma. Their combined use in prognostic scoring systems may help these patients benefit from tailored treatment and obtain better oncological results.


Assuntos
Carcinoma/diagnóstico por imagem , Imagem de Difusão por Ressonância Magnética/estatística & dados numéricos , Neoplasias Hipofaríngeas/diagnóstico por imagem , Imagem por Ressonância Magnética/estatística & dados numéricos , Tomografia Computadorizada com Tomografia por Emissão de Pósitrons/estatística & dados numéricos , Adulto , Carcinoma/mortalidade , Carcinoma/patologia , Imagem de Difusão por Ressonância Magnética/métodos , Feminino , Fluordesoxiglucose F18 , Humanos , Neoplasias Hipofaríngeas/mortalidade , Neoplasias Hipofaríngeas/patologia , Imagem por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Imagem Multimodal/métodos , Imagem Multimodal/estatística & dados numéricos , Estadiamento de Neoplasias , Valor Preditivo dos Testes , Prognóstico , Compostos Radiofarmacêuticos , Taxa de Sobrevida
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