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1.
Nat Commun ; 12(1): 1880, 2021 03 25.
Artigo em Inglês | MEDLINE | ID: mdl-33767174

RESUMO

Computational decision support systems could provide clinical value in whole-body FDG-PET/CT workflows. However, limited availability of labeled data combined with the large size of PET/CT imaging exams make it challenging to apply existing supervised machine learning systems. Leveraging recent advancements in natural language processing, we describe a weak supervision framework that extracts imperfect, yet highly granular, regional abnormality labels from free-text radiology reports. Our framework automatically labels each region in a custom ontology of anatomical regions, providing a structured profile of the pathologies in each imaging exam. Using these generated labels, we then train an attention-based, multi-task CNN architecture to detect and estimate the location of abnormalities in whole-body scans. We demonstrate empirically that our multi-task representation is critical for strong performance on rare abnormalities with limited training data. The representation also contributes to more accurate mortality prediction from imaging data, suggesting the potential utility of our framework beyond abnormality detection and location estimation.


Assuntos
Sistemas de Apoio a Decisões Clínicas , Interpretação de Imagem Assistida por Computador/métodos , Aprendizado de Máquina , Tomografia Computadorizada com Tomografia por Emissão de Pósitrons/métodos , Imagem Corporal Total/métodos , Conjuntos de Dados como Assunto , Fluordesoxiglucose F18 , Humanos , Comportamento Multitarefa , Processamento de Linguagem Natural
2.
Br J Radiol ; 94(1120): 20200682, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33733812

RESUMO

OBJECTIVE: To assess intra- and inter-reader variability of apparent diffusion coefficient (ADC) and fat fraction (FF) measurement in focal myeloma bone lesions and the influence of lesion size. METHODS: 22 myeloma patients with focal active disease on whole body MRI were included. Two readers outlined a small (5-10 mm) and large lesion (>10 mm) in each subject on derived ADC and FF maps; one reader performed this twice. Intra- and inter-reader agreement for small and large lesion groups were calculated for derived statistics from each map using within-subject standard deviation, coefficient of variation, interclass correlation coefficient measures, and visualized with Bland-Altman plots. RESULTS: For mean ADC, intra- and inter-reader repeatability demonstrated equivalently low coefficient of variation (3.0-3.6%) and excellent interclass correlation coefficient (0.975-0.982) for both small and large lesions. For mean FF, intra- and inter-reader repeatability was significantly poorer for small lesions compared to large lesions (intra-reader within-subject standard variation estimate is 2.7 times higher for small lesions than large lesions (p = 0.0071), and for inter-reader variations is 3.8 times higher (p = 0.0070)). CONCLUSION: There is excellent intra- and inter-reader agreement for mean ADC estimates, even for lesions as small as 5 mm. For FF measurements, there is a significant increase in coefficient of variation for smaller lesions, suggesting lesions >10 mm should be selected for lesion FF measurement. ADVANCES IN KNOWLEDGE: ADC measurements of focal myeloma have excellent intra- and inter-reader agreement. FF measurements are more susceptible to lesion size as intra- and inter-reader agreement is significantly impaired in lesions less than 10 mm.


Assuntos
Imagem por Ressonância Magnética/métodos , Mieloma Múltiplo/diagnóstico por imagem , Imagem Corporal Total/métodos , Tecido Adiposo/diagnóstico por imagem , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Projetos Piloto , Reprodutibilidade dos Testes
3.
Ann Hematol ; 100(5): 1241-1249, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33660034

RESUMO

The objective of this study is to evaluate the prognostic features of multiple myeloma (MM) using whole-body low-dose computed tomography (WBLDCT). One hundred three patients with biopsy-proven MM who underwent WBLDCT were retrospectively enrolled. The evolution of osteolytic lesions overtime was performed by measuring the maximum axial diameter at the baseline (T0) and the end of follow-up (Te), by using a cut-off value of 10 mm. The location and dimension of up to three lesions were registered. The time-to-fracture (TTF) was recorded. Sixty-three percent of patients presented a focal pattern, 22% a diffuse pattern, and 15% a combined one. Seventy-two percent of patients with lesions ≤ 10 mm presented stability, 27% a dimensional increase, and 1% a decrease. Patients with lesions >10 mm showed a statistically significant difference regarding the mean difference of axial diameter between T0 and Te (p = 0.015). Patients with lesions >10 mm showed an odds ratio (OR) of 29.8 (95%CIs 3.8-230.5) to develop at least one fracture. Mean TTF was significantly lower in patients with lesions >10 mm in comparison with lesions ≤ 10 mm (9 ± 3 vs 23 ± 7 months, respectively, p = 0.011). WBLDCT represents a reliable imaging-based tool for proper management of MM patients, showing that diffuse form or small lytic lesions may deserve a less frequent follow-up.


Assuntos
Mieloma Múltiplo/diagnóstico por imagem , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Mieloma Múltiplo/patologia , Estadiamento de Neoplasias/métodos , Doses de Radiação , Estudos Retrospectivos , Tomografia Computadorizada por Raios X/métodos , Imagem Corporal Total/métodos
4.
Br J Radiol ; 94(1120): 20210043, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33571003

RESUMO

OBJECTIVE: A new Bayesian penalized likelihood reconstruction algorithm for positron emission tomography (PET) (Q.Clear) is now in clinical use for fludeoxyglucose (FDG) PET/CT. However, experience with non-FDG tracers and in special patient populations is limited. This pilot study aims to compare Q.Clear to standard PET reconstructions for 18F sodium fluoride (18F-NaF) PET in obese patients. METHODS: 30 whole body 18F-NaF PET/CT scans (10 patients with BMI 30-40 Kg/m2 and 20 patients with BMI >40 Kg/m2) and a NEMA image quality phantom scans were analyzed using ordered subset expectation maximization (OSEM) and Q.Clear reconstructions methods with B400, 600, 800 and 1000. The images were assessed for overall image quality (IQ), noise level, background soft tissue, and lesion detectability, contrast recovery (CR), background variability (BV) and contrast-to-noise ratio (CNR) for both algorithms. RESULTS: CNR for clinical cases was higher for Q.Clear than OSEM (p < 0.05). Mean CNR for OSEM was (21.62 ± 8.9), and for Q.Clear B400 (31.82 ± 14.6), B600 (35.54 ± 14.9), B800 (39.81 ± 16.1), and B1000 (40.9 ± 17.8). As the ß value increased the CNR increased in all clinical cases. B600 was the preferred ß value for reconstruction in obese patients. The phantom study showed Q.Clear reconstructions gave lower CR and lower BV than OSEM. The CNR for all spheres was significantly higher for Q.Clear (independent of ß) than OSEM (p < 0.05), suggesting superiority of Q.Clear. CONCLUSION: This pilot clinical study shows that Q.Clear reconstruction algorithm improves overall IQ of 18F-NaF PET in obese patients. Our clinical and phantom measurement results demonstrate improved CNR and reduced BV when using Q.Clear. A ß value of 600 is preferred for reconstructing 18F-NaF PET/CT with Q.Clear in obese patients. ADVANCES IN KNOWLEDGE: 18F-NaF PET/CT is less susceptible to artifacts induced by body habitus. Bayesian penalized likelihood reconstruction with18F-NaF PET improves overall IQ in obese patients.


Assuntos
Neoplasias Ósseas/diagnóstico por imagem , Radioisótopos de Flúor , Interpretação de Imagem Assistida por Computador/métodos , Obesidade/complicações , Tomografia Computadorizada com Tomografia por Emissão de Pósitrons/métodos , Fluoreto de Sódio , Algoritmos , Teorema de Bayes , Neoplasias Ósseas/complicações , Neoplasias Ósseas/secundário , Osso e Ossos/diagnóstico por imagem , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Imagem Corporal Total/métodos
5.
Br J Radiol ; 94(1121): 20201329, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33571010

RESUMO

OBJECTIVES: To evaluate image quality and lesion detection capabilities of low-dose (LD) portal venous phase whole-body computed tomography (CT) using deep learning image reconstruction (DLIR). METHODS: The study cohort of 59 consecutive patients (mean age, 67.2 years) who underwent whole-body LD CT and a prior standard-dose (SD) CT reconstructed with hybrid iterative reconstruction (SD-IR) within one year for surveillance of malignancy were assessed. The LD CT images were reconstructed with hybrid iterative reconstruction of 40% (LD-IR) and DLIR (LD-DLIR). The radiologists independently evaluated image quality (5-point scale) and lesion detection. Attenuation values in Hounsfield units (HU) of the liver, pancreas, spleen, abdominal aorta, and portal vein; the background noise and signal-to-noise ratio (SNR) of the liver, pancreas, and spleen were calculated. Qualitative and quantitative parameters were compared between the SD-IR, LD-IR, and LD-DLIR images. The CT dose-index volumes (CTDIvol) and dose-length product (DLP) were compared between SD and LD scans. RESULTS: The image quality and lesion detection rate of the LD-DLIR was comparable to the SD-IR. The image quality was significantly better in SD-IR than in LD-IR (p < 0.017). The attenuation values of all anatomical structures were comparable between the SD-IR and LD-DLIR (p = 0.28-0.96). However, background noise was significantly lower in the LD-DLIR (p < 0.001) and resulted in improved SNRs (p < 0.001) compared to the SD-IR and LD-IR images. The mean CTDIvol and DLP were significantly lower in the LD (2.9 mGy and 216.2 mGy•cm) than in the SD (13.5 mGy and 1011.6 mGy•cm) (p < 0.0001). CONCLUSION: LD CT images reconstructed with DLIR enable radiation dose reduction of >75% while maintaining image quality and lesion detection rate and superior SNR in comparison to SD-IR. ADVANCES IN KNOWLEDGE: Deep learning image reconstruction algorithm enables around 80% reduction in radiation dose while maintaining the image quality and lesion detection compared to standard-dose whole-body CT.


Assuntos
Aprendizado Profundo , Neoplasias/diagnóstico por imagem , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Tomografia Computadorizada por Raios X/métodos , Imagem Corporal Total/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Algoritmos , Meios de Contraste/administração & dosagem , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias/tratamento farmacológico , Neoplasias/cirurgia , Período Pós-Operatório , Estudos Prospectivos , Controle de Qualidade , Doses de Radiação , Razão Sinal-Ruído , Tomografia Computadorizada por Raios X/normas
6.
Cancer Imaging ; 21(1): 5, 2021 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-33413685

RESUMO

BACKGROUND: We prospectively evaluated the diagnostic utility of whole-body diffusion-weighted imaging with background body signal suppression and T2-weighted short-tau inversion recovery MRI (WB-DWIBS/STIR) for the pretherapeutic staging of indolent lymphoma in 30 patients. METHODS: This prospective study included 30 treatment-naive patients with indolent lymphomas who underwent WB-DWIBS/STIR and conventional imaging workup plus biopsy. The pretherapeutic staging agreement, sensitivity, and specificity of WB-DWIBS/STIR were investigated with reference to the multimodality and multidisciplinary consensus review for nodal and extranodal lesions excluding bone marrow. RESULTS: In the pretherapeutic staging, WB-DWIBS/STIR showed very good agreement (κ = 0.96; confidence interval [CI], 0.88-1.00), high sensitivity (93.4-95.1%), and high specificity (99.0-99.4%) for the whole-body regions. These results were similar to those of 18F-FDG-PET/CT, except for the sensitivity for extranodal lesions. For extranodal lesions, WB-DWIBS/STIR showed higher sensitivity compared to 18F-FDG-PET/CT for the whole-body regions (94.9-96.8% vs. 79.6-86.3%, P = 0.058). CONCLUSION: WB-DWIBS/STIR is an effective modality for the pretherapeutic staging of indolent lymphoma, and it has benefits when evaluating extranodal lesions, compared with 18F-FDG-PET/CT.


Assuntos
Imagem de Difusão por Ressonância Magnética/métodos , Linfoma/diagnóstico por imagem , Tomografia Computadorizada com Tomografia por Emissão de Pósitrons/métodos , Imagem Corporal Total/métodos , Adulto , Idoso , Biópsia , Feminino , Fluordesoxiglucose F18 , Humanos , Linfoma/patologia , Masculino , Pessoa de Meia-Idade , Imagem Multimodal/métodos , Estudos Prospectivos , Compostos Radiofarmacêuticos , Sensibilidade e Especificidade , Adulto Jovem
7.
AJR Am J Roentgenol ; 216(3): 742-751, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33439048

RESUMO

OBJECTIVE. The purpose of this article is to analyze whole-body low-dose CT-detected appendicular medullary patterns of attenuation in patients with newly diagnosed multiple myeloma and to determine the diagnostic performance of whole-body low-dose CT in detecting diffuse marrow infiltration. MATERIALS AND METHODS. A total of 76 patients with myeloma who underwent whole-body low-dose CT and spinal MRI at initial assessment were retrospectively analyzed. The medullary cavities of femurs and humeri were evaluated qualitatively and quantitatively on CT. Medullary attenuation and SD-to-mean attenuation ratio were recorded for each long bone. The pattern of marrow involvement on spinal MRI was used as reference. The chi-square test was used to evaluate the relationship between the CT-based appendicular medullary cavity pattern and the MRI pattern, and ROC analysis was performed to assess the diagnostic accuracy of CT attenuation measurements for the differentiation between diffuse and mixed CT-based appendicular medullary cavity patterns. RESULTS. Medullary attenuation differed significantly among mixed, nodular, and diffuse CT-based appendicular medullary cavity patterns in the femurs (mean, 34.23 HU and range, 15-61 HU; mean, 66.26 HU and range, 26-104 HU; mean, 92.80 HU and range, 53-127 HU, respectively) and humeri (mean, 22.18 HU and range, 9-41; mean, 61.18 HU and range, 23-93 HU; mean, 77.50 and range, 25-105 HU, respectively). To discriminate between diffuse and mixed CT-based appendicular medullary cavity patterns, optimal cutoff attenuation values were 63 HU (sensitivity, 97.7%; specificity, 100.0%) for the femurs, and 52 HU (sensitivity, 97.4%; specificity, 100.0%) for the humeri. A total of 24 of 30 (80.0%) patients with a diffuse MRI pattern showed a diffuse CT-based appendicular medullary cavity pattern on whole-body low-dose CT, and all patients with a diffuse CT-based appendicular medullary cavity pattern also showed a diffuse pattern on MRI. CONCLUSION. According to analysis of peripheral medullary patterns of attenuation, whole-body low-dose CT can identify patients with multiple myeloma with diffuse marrow involvement.


Assuntos
Medula Óssea/diagnóstico por imagem , Imagem por Ressonância Magnética/métodos , Mieloma Múltiplo/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Imagem Corporal Total/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Área Sob a Curva , Distribuição de Qui-Quadrado , Feminino , Fêmur/diagnóstico por imagem , Humanos , Úmero/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Doses de Radiação , Estudos Retrospectivos , Sensibilidade e Especificidade , Coluna Vertebral/diagnóstico por imagem
8.
Medicine (Baltimore) ; 100(2): e24205, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33466198

RESUMO

OBJECTIVES: Controversies emerge over routine performances of whole-body computed tomography (WBCT) in patients with blunt polytrauma. The existing randomized and non-randomized evidence is inconclusive, and during observations of non-trauma, incidental findings, detected by WBCT, have left uncertainty regarding their consequences and optimal management. Additionally, previous meta-analyses have failed to address the limitations of primary studies and issues associated with incidental findings. Therefore, we planned a new systematic review to address these points. METHODS: We will search the PubMed, EMBASE, and Cochrane Central databases from inception to December 31, 2020, with no language restriction and perform full-text evaluation of potentially relevant articles. We will include prospective and retrospective studies with a single-gate design that assessed diagnostic accuracy and/or yield of WBCT to detect traumatic injuries, and studies that assessed incidental findings detected by WBCT. Additionally, we will include randomized controlled trials and non-randomized comparative studies that assessed the effectiveness of WBCT against conventional care, including selective computed tomography (CT). Studies of patients of all ages with blunt traumatic injuries, assessed at an emergency department, will be included. Two reviewers will extract data and rate the study validity via standard quality assessment tools. The primary outcome of interest will be reduction in mortality. Our secondary outcomes will include diagnostic accuracy and yield, detection of incidental findings and clinical outcomes associated with these detections, and improvement in other non-mortality clinical outcomes. We will qualitatively assess study, patient, and intervention characteristics and clinical outcomes. If appropriate, we will perform random-effects model meta-analyses to obtain summary estimates. Finally, we will assess the certainty of evidence by the grading the quality of evidence and strength of recommendations. ETHICS AND DISSEMINATION: Ethics approval is not applicable, as this is a secondary analysis of publicly available data. The review results will be submitted for publication in peer-reviewed journals. PROSPERO REGISTRATION: CRD42020187852.


Assuntos
Protocolos Clínicos , Imagem Corporal Total/normas , Ferimentos não Penetrantes/diagnóstico por imagem , Humanos , Metanálise como Assunto , Sensibilidade e Especificidade , Revisões Sistemáticas como Assunto , Tomografia Computadorizada por Raios X/métodos , Tomografia Computadorizada por Raios X/normas , Imagem Corporal Total/métodos
9.
Nat Commun ; 12(1): 455, 2021 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-33469005

RESUMO

The technology of magnetic resonance imaging is developing towards higher magnetic fields to improve resolution and contrast. However, whole-body imaging at 7 T or even higher flux densities remains challenging due to wave interference, tissue inhomogeneities, and high RF power deposition. Nowadays, proper RF excitation of a human body in prostate and cardiac MRI is only possible to achieve by using phased arrays of antennas attached to the body (so-called surface coils). Due to safety concerns, the design of such coils aims at minimization of the local specific absorption rate (SAR), keeping the highest possible RF signal in the region of interest. Most previously demonstrated approaches were based on resonant structures such as e.g. dipoles, capacitively-loaded loops, TEM-line sections. In this study, we show that there is a better compromise between the transmit signal [Formula: see text] and the local SAR using non-resonant surface coils generating a low electric field in the proximity of their conductors. With this aim, we propose and experimentally demonstrate a leaky-wave antenna implemented as a periodically-slotted microstrip transmission line. Due to its non-resonant radiation, it induces only slightly over half the peak local SAR compared to a state-of-the-art dipole antenna but has the same transmit efficiency in prostate imaging at 7 T. Unlike other antennas for MRI, the leaky-wave antenna does not require to be tuned and matched when placed on a body, which makes it easy-to-use in prostate imaging at 7 T MRI.


Assuntos
Imagem por Ressonância Magnética/instrumentação , Imagem Corporal Total/instrumentação , Absorção de Radiação , Radiação Eletromagnética , Desenho de Equipamento , Humanos , Campos Magnéticos/efeitos adversos , Imagem por Ressonância Magnética/efeitos adversos , Imagem por Ressonância Magnética/métodos , Imagens de Fantasmas , Imagem Corporal Total/efeitos adversos , Imagem Corporal Total/métodos
10.
PET Clin ; 16(1): 89-97, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33160926

RESUMO

Total-body PET enables high-sensitivity imaging with dramatically improved signal-to-noise ratio. These enhanced performance characteristics allow for decreased PET scanning times acquiring data "total-body wide" and can be leveraged to decrease the amount of radiotracer required, thereby permitting more frequent imaging or longer imaging periods during radiotracer decay. Novel approaches to PET imaging of infectious diseases are emerging, including those that directly visualize pathogens in vivo and characterize concomitant immune responses and inflammation. Efforts to develop these imaging approaches are hampered by challenges of traditional imaging platforms, which may be overcome by novel total-body PET strategies.


Assuntos
Doenças Transmissíveis/diagnóstico por imagem , Tomografia por Emissão de Pósitrons/métodos , Imagem Corporal Total/métodos , Humanos , Razão Sinal-Ruído , Tempo
11.
J Vis Exp ; (163)2020 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-32955492

RESUMO

Biomedical imaging tools permit investigation of molecular mechanisms across spatial scales, from genes to organisms. Drosophila melanogaster, a well-characterized model organism, has benefited from the use of light and electron microscopy to understand gene function at the level of cells and tissues. The application of imaging platforms that allow for an understanding of gene function at the level of the entire intact organism would further enhance our knowledge of genetic mechanisms. Here a whole animal imaging method is presented that outlines the steps needed to visualize Drosophila at any developmental stage using microcomputed tomography (µ-CT). The advantages of µ-CT include commercially available instrumentation and minimal hands-on time to produce accurate 3D information at micron-level resolution without the need for tissue dissection or clearing methods. Paired with software that accelerate image analysis and 3D rendering, detailed morphometric analysis of any tissue or organ system can be performed to better understand mechanisms of development, physiology, and anatomy for both descriptive and hypothesis testing studies. By utilizing an imaging workflow that incorporates the use of electron microscopy, light microscopy, and µ-CT, a thorough evaluation of gene function can be performed, thus furthering the usefulness of this powerful model organism.


Assuntos
Drosophila melanogaster , Imagem Corporal Total/métodos , Microtomografia por Raio-X/métodos , Animais , Drosophila melanogaster/crescimento & desenvolvimento , Imageamento Tridimensional , Software
12.
Medicine (Baltimore) ; 99(33): e20021, 2020 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-32871968

RESUMO

To evaluate the diagnostic performance of net influx rate (Ki) values from a whole-body dynamic (WBD) Ga-DOTATOC-PET/CT acquisition to differentiate pancreatic neuroendocrine tumors (pNETs) from physiological uptake of pancreatic uncinate process (UP).Patients who were benefited from a WBD acquisition for the assessment of a known well-differentiated neuroendocrine tumor (NET)/suspicion of disease in the prospective GAPET-NET cohort were screened. Only patients with a confirmed pNET/UP as our gold standard were included. The positron emission tomography (PET) procedure consisted in a single-bed dynamic acquisition centered on the heart, followed by a whole-body dynamic acquisition and then a static acquisition. Dynamic (Ki calculated according to Patlak method), static (SUVmax, SUVmean, SUVpeak) parameters, and tumor-to-liver and tumor-to-spleen ratio (TLRKi and TSRKi (according to hepatic/splenic Ki)), tumor SUVmax to liver SUVmax (TM/LM), tumor SUVmax to liver SUVmean (TM/Lm), tumor SUVmax to spleen SUVmax (TM/SM), and tumor SUVmax to spleen SUVmean (TM/Sm) (according to hepatic/splenic SUVmax and SUVmean respectively) were calculated. A Receiver Operating Characteristic (ROC) analysis was performed to evaluate their diagnostic performance to distinguish UP from pNET.One hundred five patients benefited from a WBD between July 2018 and July 2019. Eighteen (17.1%) had an UP and 26 (24.8%) a pNET. For parameters alone, the Ki and SUVpeak had the best sensitivity (88.5%) while the Ki, SUVmax, and SUVmean had the best specificity (94.4%). The best diagnostic accuracy was obtained with Ki (90.9%). For ratios, the TLRKi and the TSRKi had the best sensitivity (95.7%) while the TM/SM and TM/Sm the best specificity (100%). TLRKi had the best diagnostic accuracy (95.1%) and the best area under the curve (AUC) (0.990).Our study is the first one to evaluate the interest of a WBD acquisition to differentiate UP from pNETs and shows excellent diagnostic performances of the Ki approach.


Assuntos
Tumores Neuroendócrinos/diagnóstico por imagem , Pâncreas/diagnóstico por imagem , Neoplasias Pancreáticas/diagnóstico por imagem , Tomografia Computadorizada com Tomografia por Emissão de Pósitrons , Imagem Corporal Total , Diagnóstico Diferencial , Feminino , Humanos , Fígado/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Octreotida/análogos & derivados , Compostos Organometálicos , Tomografia Computadorizada com Tomografia por Emissão de Pósitrons/métodos , Estudos Prospectivos , Compostos Radiofarmacêuticos , Sensibilidade e Especificidade , Baço/diagnóstico por imagem , Imagem Corporal Total/métodos
13.
Br J Radiol ; 93(1115): 20200562, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32822545

RESUMO

Whole-body MRI (WB-MRI) has evolved since its first introduction in the 1970s as an imaging technique to detect and survey disease across multiple sites and organ systems in the body. The development of diffusion-weighted MRI (DWI) has added a new dimension to the implementation of WB-MRI on modern scanners, offering excellent lesion-to-background contrast, while achieving acceptable spatial resolution to detect focal lesions 5 to 10 mm in size. MRI hardware and software advances have reduced acquisition times, with studies taking 40-50 min to complete.The rising awareness of medical radiation exposure coupled with the advantages of MRI has resulted in increased utilization of WB-MRI in oncology, paediatrics, rheumatological and musculoskeletal conditions and more recently in population screening. There is recognition that WB-MRI can be used to track disease evolution and monitor response heterogeneity in patients with cancer. There are also opportunities to combine WB-MRI with molecular imaging on PET-MRI systems to harness the strengths of hybrid imaging. The advent of artificial intelligence and machine learning will shorten image acquisition times and image analyses, making the technique more competitive against other imaging technologies.


Assuntos
Predisposição Genética para Doença , Imagem por Ressonância Magnética/métodos , Neoplasias/diagnóstico por imagem , Imagem Corporal Total/métodos , Imagem de Difusão por Ressonância Magnética/tendências , Feminino , História do Século XXI , Humanos , Achados Incidentais , Imagem por Ressonância Magnética/tendências , Masculino , Imagem Multimodal/métodos , Neoplasias/genética , Tomografia por Emissão de Pósitrons/métodos , Exposição à Radiação/prevenção & controle , Fatores de Tempo
14.
PLoS One ; 15(8): e0237213, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32797099

RESUMO

Bone metastasis is one of the most frequent diseases in prostate cancer; scintigraphy imaging is particularly important for the clinical diagnosis of bone metastasis. Up to date, minimal research has been conducted regarding the application of machine learning with emphasis on modern efficient convolutional neural networks (CNNs) algorithms, for the diagnosis of prostate cancer metastasis from bone scintigraphy images. The advantageous and outstanding capabilities of deep learning, machine learning's groundbreaking technological advancement, have not yet been fully investigated regarding their application in computer-aided diagnosis systems in the field of medical image analysis, such as the problem of bone metastasis classification in whole-body scans. In particular, CNNs are gaining great attention due to their ability to recognize complex visual patterns, in the same way as human perception operates. Considering all these new enhancements in the field of deep learning, a set of simpler, faster and more accurate CNN architectures, designed for classification of metastatic prostate cancer in bones, is explored. This research study has a two-fold goal: to create and also demonstrate a set of simple but robust CNN models for automatic classification of whole-body scans in two categories, malignant (bone metastasis) or healthy, using solely the scans at the input level. Through a meticulous exploration of CNN hyper-parameter selection and fine-tuning, the best architecture is selected with respect to classification accuracy. Thus a CNN model with improved classification capabilities for bone metastasis diagnosis is produced, using bone scans from prostate cancer patients. The achieved classification testing accuracy is 97.38%, whereas the average sensitivity is approximately 95.8%. Finally, the best-performing CNN method is compared to other popular and well-known CNN architectures used for medical imaging, like VGG16, ResNet50, GoogleNet and MobileNet. The classification results show that the proposed CNN-based approach outperforms the popular CNN methods in nuclear medicine for metastatic prostate cancer diagnosis in bones.


Assuntos
Neoplasias Ósseas/secundário , Redes Neurais de Computação , Neoplasias da Próstata/patologia , Imagem Corporal Total/métodos , Neoplasias Ósseas/classificação , Neoplasias Ósseas/diagnóstico por imagem , Diagnóstico por Computador/métodos , Humanos , Interpretação de Imagem Assistida por Computador/métodos , Aprendizado de Máquina , Masculino , Cintilografia/métodos , Software
15.
PLoS One ; 15(8): e0238166, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32853252

RESUMO

BACKGROUND: The purpose of this study was to determine whether whole-body MRI (WBMRI) with diffusion-weighted sequences, which is free of ionizing radiation, can perform as well as traditional methods when used alone for staging or follow-up of pediatric cancer patients. METHODS: After obtaining approval from our institutional research ethics committee and appropriate informed consent, we performed 34 examinations in 32 pediatric patients. The examinations were anonymized and analyzed by two radiologists with at least 10 years' experience. RESULTS: The sensitivity and specificity findings, respectively, were as follows: 100% and 100% for primary tumor; 100% and 86% for bone metastasis; 33% and 100% for lung metastasis; 85% and 100% for lymph node metastasis; and 100% and 62% for global investigation of primary or secondary neoplasias. We observed excellent interobserver agreement for WBMRI and excellent agreement with standard staging examination results. CONCLUSIONS: Our results suggest that pediatric patients can be safely imaged with WBMRI, although not as the only tool but in association with low-dose chest CT (for subcentimeter pulmonary nodules). However, additional exams with ionizing radiation may be necessary for patients who tested positive to correctly quantify and locate the lesions.


Assuntos
Neoplasias/patologia , Adolescente , Criança , Pré-Escolar , Estudos Transversais , Imagem de Difusão por Ressonância Magnética/métodos , Feminino , Humanos , Masculino , Estadiamento de Neoplasias/métodos , Estudos Prospectivos , Sensibilidade e Especificidade , Imagem Corporal Total/métodos
16.
Eur J Epidemiol ; 35(10): 925-935, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32860149

RESUMO

Magnetic resonance imaging (MRI) yields numerous tumor-related incidental findings (IFs) which may trigger diagnostics such as biopsies. To clarify these effects, we studied how whole-body MRI IF disclosure in a population-based cohort affected biopsy frequency and the detection of malignancies. Laboratory disclosures were also assessed. Data from 6753 participants in the Study of Health in Pomerania (SHIP) examined between 2008 and 2012 were utilized. All underwent laboratory examinations and 3371 (49.9%) a whole-body MRI. Electronic biopsy reports from 2002 to 2017 were linked to participants and assigned to outcome categories. Biopsy frequency 2 years pre- and post-SHIP was investigated using generalized estimating equations with a negative-binomial distribution. Overall 8208 IFs (laboratory findings outside reference limits: 6839; MRI: 1369) were disclosed to 4707 participants; 2271 biopsy reports belonged to 1200 participants (17.8%). Of these, 938 biopsies occurred pre-SHIP; 1333 post-SHIP (event rate/100 observation years = 6.9 [95% CI 6.5; 7.4]; 9.9 [9.3; 10.4]). Age, cancer history, recent hospitalization, female sex, and IF disclosure were associated with higher biopsy rates. Nonmalignant biopsy results increased more in participants with disclosures (post-/pre-SHIP rate ratio 1.39 [95% CI 1.22; 1.58]) than without (1.09 [95% CI 0.85; 1.38]). Malignant biopsy results were more frequent post-SHIP (rate ratio 1.74 [95% CI 1.27; 2.42]). Biopsies increased after participation in a population-based cohort study with MRI and laboratory IF disclosure. Most biopsies resulted in no findings and few malignancies were diagnosed, indicating potential overtesting and overdiagnosis. A more restrictive policy regarding IF disclosure from research findings is required.


Assuntos
Biópsia/estatística & dados numéricos , Achados Incidentais , Imagem por Ressonância Magnética/métodos , Imagem Corporal Total/métodos , Adulto , Idoso , Estudos de Coortes , Revelação , Feminino , Humanos , Masculino , Registro Médico Coordenado , Pessoa de Meia-Idade , Vigilância da População , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
17.
Br J Radiol ; 93(1115): 20200312, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32667830

RESUMO

There have been major advances in myeloma imaging over the past few years with focal lesions on imaging now forming part of the disease defining criteria. Whole body diffusion-weighted MRI (WB-MRI) is considered the most sensitive technique for the detection of focal active lesions. This pictorial review will focus on imaging the spectrum of myelomatous disorders on WB-MRI including diffusion and Dixon sequences. The typical imaging patterns of disease are demonstrated including in the contexts of staging, presumed solitary plasmacytoma, smouldering myeloma and examples of paramedullary and extramedullary disease. The utility of diffusion-weighted imaging in response assessment is a major advantage and this will be exemplified here.


Assuntos
Neoplasias da Medula Óssea/diagnóstico por imagem , Imagem de Difusão por Ressonância Magnética/métodos , Mieloma Múltiplo/diagnóstico por imagem , Plasmocitoma/diagnóstico por imagem , Imagem Corporal Total/métodos , Idoso , Medula Óssea/diagnóstico por imagem , Neoplasias da Medula Óssea/terapia , Feminino , Humanos , Achados Incidentais , Imagem por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Mieloma Múltiplo/terapia
18.
Cancer Imaging ; 20(1): 48, 2020 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-32665028

RESUMO

BACKGROUND: Whole body magnetic resonance imaging (MRI) is now incorporated into international guidance for imaging patients with multiple myeloma. The aim of this study was to investigate inter-observer agreement of triple reported baseline whole-body MRI in myeloma and highlight potential pitfalls. METHODS: Fifty-seven patients with symptomatic myeloma at first presentation or relapse and planned for autologous stem cell transplant were included. All patients completed baseline whole body MRI within 2 weeks prior to starting treatment. Each scan was reported independently by 3 radiologists using a defined scoring system. Differences in observer scores were compared using analysis of variance (ANOVA) and inter-observer agreement assessed using intra class correlation coefficient (ICC). RESULTS: There was no significant difference in mean observer scores for whole skeleton and ICC demonstrated excellent inter-observer agreement at 0.91. ICC varied between skeletal regions with spine, pelvis and ribs showing good inter-observer agreement, whereas skull and long bones were moderate. Scans with variation in observer scores were re-examined and cause of discrepancies identified. This information was used to describe potential anatomical pitfalls in reporting . CONCLUSION: Whole-body MRI has excellent inter-observer agreement in reporting symptomatic myeloma at baseline. Inter-observer agreement varied between skeletal regions highlighting specific areas of difficulty.


Assuntos
Imagem por Ressonância Magnética/normas , Mieloma Múltiplo/diagnóstico por imagem , Imagem Corporal Total/normas , Feminino , Humanos , Imagem por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Reprodutibilidade dos Testes , Imagem Corporal Total/métodos
19.
Pediatr Blood Cancer ; 67(7): e28389, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32386119

RESUMO

BACKGROUND: Germline retinoblastoma (Rb) survivors are at lifelong risk for developing subsequent malignancies (SMNs). Optimal surveillance modalities are needed to detect SMN at an early stage in this high-risk cohort. We investigated the use of rapid whole-body magnetic resonance imaging (WB-MRI) as a noninvasive screening modality in this cohort. PROCEDURE: WB-MRI was performed in asymptomatic preadolescent, adolescent, or young adult survivors of germline Rb from February 1, 2008 to December 31, 2018 at a tertiary cancer center. We calculated sensitivity and specificity of WB-MRI and rate of false-positive findings requiring additional evaluation. RESULTS: Overall, 110 WB-MRI were performed in 47 germline Rb survivors (51% female; median age at initial WB-MRI: 15.5 years [range 8-25.3]). Patients received 1-10 annual WB-MRI examinations (median: two). Thirteen patients had an abnormal WB-MRI; three findings were deemed to be likely benign and were not evaluated further. Ten patients required dedicated imaging and three required biopsy; two patients were diagnosed with localized high-grade osteosarcoma, while the other eight had benign findings. One patient was diagnosed with secondary osteosarcoma 3 months after normal WB-MRI. In total, there were 96 true negatives, 11 false positives, two true positives, and one false negative. The sensitivity of WB-MRI in this cohort was 66.7% (95% confidence interval [CI], 14.2-96.0) and the specificity was 89.7% (95% CI, 83.6-93.7). CONCLUSIONS: Based on our 10-year experience, surveillance WB-MRI appears to have limited utility as a surveillance modality for SMN in germline Rb survivors. Alternate screening modalities should be investigated.


Assuntos
Imagem por Ressonância Magnética/métodos , Segunda Neoplasia Primária/diagnóstico , Neoplasias da Retina/terapia , Retinoblastoma/terapia , Imagem Corporal Total/métodos , Adolescente , Adulto , Sobreviventes de Câncer , Criança , Feminino , Seguimentos , Células Germinativas , Humanos , Incidência , Masculino , Segunda Neoplasia Primária/diagnóstico por imagem , Segunda Neoplasia Primária/epidemiologia , New York/epidemiologia , Vigilância da População , Prognóstico , Neoplasias da Retina/patologia , Retinoblastoma/patologia , Estudos Retrospectivos , Taxa de Sobrevida , Adulto Jovem
20.
Cancer Imaging ; 20(1): 34, 2020 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-32393345

RESUMO

BACKGROUND: The number of studies describing the use of whole-body magnetic resonance imaging (WB-MRI) for screening of malignant tumours in asymptomatic subjects is increasing. Our aim is to review the methodologies used and the results of the published studies on per patient and per lesion analysis, and to provide recommendations on the use of WB-MRI for cancer screening. MAIN BODY: We identified 12 studies, encompassing 6214 WB-MRI examinations, which provided the rates of abnormal findings and findings suspicious for cancer in asymptomatic subjects, from the general population. Eleven of 12 studies provided imaging protocols that included T1- and T2-weighted sequences, while only five included diffusion weighted imaging (DWI) of the whole body. Different categorical systems were used for the classification and the management of abnormal findings. Of 17,961 abnormal findings reported, 91% were benign, while 9% were oncologically relevant, requiring further investigations, and 0.5% of lesions were suspicious for cancer. A per-subject analysis showed that just 5% of subjects had no abnormal findings, while 95% had abnormal findings. Findings requiring further investigation were reported in 30% of all subjects, though in only 1.8% cancer was suspected. The overall rate of histologically confirmed cancer was 1.1%. CONCLUSION: WB-MRI studies of cancer screening in the asymptomatic general population are too heterogeneous to draw impactful conclusions regarding efficacy. A 5-point lesion scale based on the oncological relevance of findings appears the most appropriate for risk-based management stratification. WB-MRI examinations should be reported by experienced oncological radiologists versed on WB-MRI reading abnormalities and on onward referral pathways.


Assuntos
Imagem por Ressonância Magnética/métodos , Neoplasias/diagnóstico por imagem , Imagem Corporal Total/métodos , Detecção Precoce de Câncer/métodos , Humanos , Guias de Prática Clínica como Assunto
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