Assessment of deep learning-based reconstruction on T2-weighted and diffusion-weighted prostate MRI image quality.

PURPOSE: To evaluate the impact of a commercially available deep learning-based reconstruction (DLR) algorithm with varying combinations of DLR noise reduction settings and imaging parameters on quantitative and qualitative image quality, PI-RADS classification and examination time in prostate T2-weighted (T2WI) and diffusion-weighted (DWI) imaging. METHOD: Forty patients were included. Standard-of-care (SoC) prostate MRI sequences including T2WI and DWI were reconstructed without and with different DLR de-noising levels (low, medium, high). In addition, faster T2WI(Fast) and DWI(Fast) sequences, and a higher resolution T2WI(HR) sequence were evaluated. Quantitative analysis included signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and apparent diffusion coefficient (ADC) values. Two radiologists performed qualitative analysis, independently evaluating imaging datasets using 5-point scoring scales for image quality and artifacts. PI-RADS category assignment was also performed by the more experienced radiologist. RESULTS: All DLR levels resulted in significantly higher SNR and CNR compared to the DLR(off) acquisitions. DLR allowed the acquisition time to be reduced by 33% for T2WI(Fast) and 49% for DWI(Fast) compared to SoC, without affecting image quality, whilst T2WI(HR) with DLR allowed for a 73% increase in spatial resolution in the phase encode direction compared to SoC. The inter-reader agreement for image quality and artifact scores was substantial for all subjective measurements on T2WI and DWI. The T2WI(Fast) protocol with DLR(medium) and DWI(Fast) with DLR(low) received the highest qualitative quality score. CONCLUSION: DLR can reduce T2WI and DWI acquisition time and increase SNR and CNR without compromising image quality or altering PI-RADS classification.

Imaging Glioblastoma Metabolism by Using Hyperpolarized [1-13C]Pyruvate Demonstrates Heterogeneity in Lactate Labeling: A Proof of Principle Study.

Purpose To evaluate glioblastoma (GBM) metabolism by using hyperpolarized carbon 13 (13C) MRI to monitor the exchange of the hyperpolarized 13C label between injected [1-13C]pyruvate and tumor lactate and bicarbonate. Materials and Methods In this prospective study, seven treatment-naive patients (age [mean ± SD], 60 years ± 11; five men) with GBM were imaged at 3 T by using a dual-tuned 13C-hydrogen 1 head coil. Hyperpolarized [1-13C]pyruvate was injected, and signal was acquired by using a dynamic MRI spiral sequence. Metabolism was assessed within the tumor, in the normal-appearing brain parenchyma (NABP), and in healthy volunteers by using paired or unpaired t tests and a Wilcoxon signed rank test. The Spearman ρ correlation coefficient was used to correlate metabolite labeling with lactate dehydrogenase A (LDH-A) expression and some immunohistochemical markers. The Benjamini-Hochberg procedure was used to correct for multiple comparisons. Results The bicarbonate-to-pyruvate (BP) ratio was lower in the tumor than in the contralateral NABP (P < .01). The tumor lactate-to-pyruvate (LP) ratio was not different from that in the NABP (P = .38). The LP and BP ratios in the NABP were higher than those observed previously in healthy volunteers (P < .05). Tumor lactate and bicarbonate signal intensities were strongly correlated with the pyruvate signal intensity (ρ = 0.92, P < .001, and ρ = 0.66, P < .001, respectively), and the LP ratio was weakly correlated with LDH-A expression in biopsy samples (ρ = 0.43, P = .04). Conclusion Hyperpolarized 13C MRI demonstrated variation in lactate labeling in GBM, both within and between tumors. In contrast, bicarbonate labeling was consistently lower in tumors than in the surrounding NABP. Keywords: Hyperpolarized 13C MRI, Glioblastoma, Metabolism, Cancer, MRI, Neuro-oncology Supplemental material is available for this article. Published under a CC BY 4.0 license.

Hyperpolarized Carbon-13 MRI for Early Response Assessment of Neoadjuvant Chemotherapy in Breast Cancer Patients.

Hyperpolarized 13C-MRI is an emerging tool for probing tissue metabolism by measuring 13C-label exchange between intravenously injected hyperpolarized [1-13C]pyruvate and endogenous tissue lactate. Here, we demonstrate that hyperpolarized 13C-MRI can be used to detect early response to neoadjuvant therapy in breast cancer. Seven patients underwent multiparametric 1H-MRI and hyperpolarized 13C-MRI before and 7-11 days after commencing treatment. An increase in the lactate-to-pyruvate ratio of approximately 20% identified three patients who, following 5-6 cycles of treatment, showed pathological complete response. This ratio correlated with gene expression of the pyruvate transporter MCT1 and lactate dehydrogenase A (LDHA), the enzyme catalyzing label exchange between pyruvate and lactate. Analysis of approximately 2,000 breast tumors showed that overexpression of LDHA and the hypoxia marker CAIX was associated with reduced relapse-free and overall survival. Hyperpolarized 13C-MRI represents a promising method for monitoring very early treatment response in breast cancer and has demonstrated prognostic potential. SIGNIFICANCE: Hyperpolarized carbon-13 MRI allows response assessment in patients with breast cancer after 7-11 days of neoadjuvant chemotherapy and outperformed state-of-the-art and research quantitative proton MRI techniques.

Multiparametric MRI of early tumor response to immune checkpoint blockade in metastatic melanoma.

BACKGROUND: Immune checkpoint inhibitors are now standard of care treatment for many cancers. Treatment failure in metastatic melanoma is often due to tumor heterogeneity, which is not easily captured by conventional CT or tumor biopsy. The aim of this prospective study was to investigate early microstructural and functional changes within melanoma metastases following immune checkpoint blockade using multiparametric MRI. METHODS: Fifteen treatment-naïve metastatic melanoma patients (total 27 measurable target lesions) were imaged at baseline and following 3 and 12 weeks of treatment on immune checkpoint inhibitors using: T2-weighted imaging, diffusion kurtosis imaging, and dynamic contrast-enhanced MRI. Treatment timepoint changes in tumor cellularity, vascularity, and heterogeneity within individual metastases were evaluated and correlated to the clinical outcome in each patient based on Response Evaluation Criteria in Solid Tumors V.1.1 at 1 year. RESULTS: Differential tumor growth kinetics in response to immune checkpoint blockade were measured in individual metastases within the same patient, demonstrating significant intertumoral heterogeneity in some patients. Early detection of tumor cell death or cell loss measured by a significant increase in the apparent diffusivity (Dapp) (p<0.05) was observed in both responding and pseudoprogressive lesions after 3 weeks of treatment. Tumor heterogeneity, as measured by apparent diffusional kurtosis (Kapp), was consistently higher in the pseudoprogressive and true progressive lesions, compared with the responding lesions throughout the first 12 weeks of treatment. These preceded tumor regression and significant tumor vascularity changes (Ktrans, ve, and vp) detected after 12 weeks of immunotherapy (p<0.05). CONCLUSIONS: Multiparametric MRI demonstrated potential for early detection of successful response to immune checkpoint inhibitors in metastatic melanoma.

Non-contrast MRI can accurately characterize adnexal masses: a retrospective study.

OBJECTIVE: To determine the accuracy of interpretation of a non-contrast MRI protocol in characterizing adnexal masses. METHODS AND MATERIALS: Two hundred ninety-one patients (350 adnexal masses) who underwent gynecological MRI at our institution between the 1st of January 2008 and the 31st of December 2018 were reviewed. A random subset (102 patients with 121 masses) was chosen to evaluate the reproducibility and repeatability of readers' assessments. Readers evaluated non-contrast MRI scans retrospectively, assigned a 5-point score for the risk of malignancy and gave a specific diagnosis. The reference standard for the diagnosis was histopathology or at least one-year imaging follow-up. Diagnostic accuracy of the non-contrast MRI score was calculated. Inter- and intra-reader agreement was analyzed with Cohen's kappa statistics. RESULTS: There were 53/350 (15.1%) malignant lesions in the whole cohort and 20/121 (16.5%) malignant lesions in the random subset. Good agreement between readers was found for the non-contrast MRI score (к = 0.73, 95% confidence interval [CI] 0.58-0.86) whilst the intra-reader agreement was excellent (к = 0.81, 95% CI 0.70-0.88). The non-contrast MRI score value of ≥ 4 was associated with malignancy with a sensitivity of 84.9%, a specificity of 95.9%, an accuracy of 94.2% and a positive likelihood ratio of 21 (area under the receiver operating curve 0.93, 95% CI 0.90-0.96). CONCLUSION: Adnexal mass characterization on MRI without the administration of contrast medium has a high accuracy and excellent inter- and intra-reader agreement. Our results suggest that non-contrast studies may offer a reasonable diagnostic alternative when the administration of intravenous contrast medium is not possible. KEY POINTS: • A non-contrast pelvic MRI protocol may allow the characterization of adnexal masses with high accuracy. • The non-contrast MRI score may be used in clinical practice for differentiating benign from malignant adnexal lesions when the lack of intravenous contrast medium precludes analysis with the O-RADS MRI score.

Reproducibility of magnetic resonance fingerprinting-based T1 mapping of the healthy prostate at 1.5 and 3.0 T: A proof-of-concept study.

Facilitating clinical translation of quantitative imaging techniques has been suggested as means of improving interobserver agreement and diagnostic accuracy of multiparametric magnetic resonance imaging (mpMRI) of the prostate. One such technique, magnetic resonance fingerprinting (MRF), has significant competitive advantages over conventional mapping techniques in terms of its multi-site reproducibility, short scanning time and inherent robustness to motion. It has also been shown to improve the detection of clinically significant prostate cancer when added to standard mpMRI sequences, however, the existing studies have all been conducted on 3.0 T MRI systems, limiting the technique's use on 1.5 T MRI scanners that are still more widely used for prostate imaging across the globe. The aim of this proof-of-concept study was, therefore, to evaluate the cross-system reproducibility of prostate MRF T1 in healthy volunteers (HVs) using 1.5 and 3.0 T MRI systems. The initial validation of MRF T1 against gold standard inversion recovery fast spin echo (IR-FSE) T1 in the ISMRM/NIST MRI system revealed a strong linear correlation between phantom-derived MRF and IR-FSE T1 values was observed at both field strengths (R2 = 0.998 at 1.5T and R2 = 0.993 at 3T; p = < 0.0001 for both). In young HVs, inter-scanner CVs demonstrated marginal differences across all tissues with the highest difference of 3% observed in fat (2% at 1.5T vs 5% at 3T). At both field strengths, MRF T1 could confidently differentiate prostate peripheral zone from transition zone, which highlights the high quantitative potential of the technique given the known difficulty of tissue differentiation in this age group. The high cross-system reproducibility of MRF T1 relaxometry of the healthy prostate observed in this preliminary study, therefore, supports the technique's prospective clinical validation as part of larger trials employing 1.5 T MRI systems, which are still widely used clinically for routine mpMRI of the prostate.

Magnetic resonance fingerprinting of the pancreas at 1.5 T and 3.0 T.

Magnetic resonance imaging of the pancreas is increasingly used as an important diagnostic modality for characterisation of pancreatic lesions. Pancreatic MRI protocols are mostly qualitative due to time constraints and motion sensitivity. MR Fingerprinting is an innovative acquisition technique that provides qualitative data and quantitative parameter maps from a single free-breathing acquisition with the potential to reduce exam times. This work investigates the feasibility of MRF parameter mapping for pancreatic imaging in the presence of free-breathing exam. Sixteen healthy participants were prospectively imaged using MRF framework. Regions-of-interest were drawn in multiple solid organs including the pancreas and T1 and T2 values determined. MRF T1 and T2 mapping was performed successfully in all participants (acquisition time:2.4-3.6 min). Mean pancreatic T1 values were 37-43% lower than those of the muscle, spleen, and kidney at both 1.5 and 3.0 T. For these organs, the mean pancreatic T2 values were nearly 40% at 1.5 T and < 12% at 3.0 T. The feasibility of MRF at 1.5 T and 3 T was demonstrated in the pancreas. By enabling fast and free-breathing quantitation, MRF has the potential to add value during the clinical characterisation and grading of pathological conditions, such as pancreatitis or cancer.

The effect of capped biparametric magnetic resonance imaging slots on weekly prostate cancer imaging workload.

OBJECTIVE: To introduce capped biparametric (bp) MRI slots for follow-up imaging of prostate cancer patients enrolled in active surveillance (AS) and evaluate the effect on weekly variation in the number of AS cases and total MRI workload. METHODS: Three 20 min bpMRI AS slots on two separate days were introduced at Addenbrooke's Hospital, Cambridge. The weekly numbers of total prostate MRIs and AS cases recorded 15 months before and after the change (Groups 1 and 2, respectively). An intergroup variation in the weekly scan numbers was assessed using the coefficient of variance (CV) and mean absolute deviation; the Mann-Whitney U test was used for an intergroup comparison of the latter. RESULTS: In AS patients, a shift from considerable to moderate variation in weekly scan numbers was observed between the two groups (CV, 51.7 and 26.8%, respectively); mean absolute deviation of AS scans also demonstrated a significant decrease in Group 2 (1.28 vs 2.58 in Group 1; p < 0.001). No significant changes in the variation in total prostate MRIs were observed, despite a 10% increased workload in Group 2. CONCLUSION: A significant reduction in weekly variation of AS cases was demonstrated following the introduction of capped bpMRI slots, which can be used for more accurate long-term planning of MRI workload. ADVANCES IN KNOWLEDGE: The paper illustrates the potential of introducing capped AS MRI slots using a bp protocol to reduce weekly variation in demand and allow for optimising workflow, which will be increasingly important as the demands on radiology departments increase worldwide.

Imaging breast cancer using hyperpolarized carbon-13 MRI.

Our purpose is to investigate the feasibility of imaging tumor metabolism in breast cancer patients using 13C magnetic resonance spectroscopic imaging (MRSI) of hyperpolarized 13C label exchange between injected [1-13C]pyruvate and the endogenous tumor lactate pool. Treatment-naïve breast cancer patients were recruited: four triple-negative grade 3 cancers; two invasive ductal carcinomas that were estrogen and progesterone receptor-positive (ER/PR+) and HER2/neu-negative (HER2-), one grade 2 and one grade 3; and one grade 2 ER/PR+ HER2- invasive lobular carcinoma (ILC). Dynamic 13C MRSI was performed following injection of hyperpolarized [1-13C]pyruvate. Expression of lactate dehydrogenase A (LDHA), which catalyzes 13C label exchange between pyruvate and lactate, hypoxia-inducible factor-1 (HIF1α), and the monocarboxylate transporters MCT1 and MCT4 were quantified using immunohistochemistry and RNA sequencing. We have demonstrated the feasibility and safety of hyperpolarized 13C MRI in early breast cancer. Both intertumoral and intratumoral heterogeneity of the hyperpolarized pyruvate and lactate signals were observed. The lactate-to-pyruvate signal ratio (LAC/PYR) ranged from 0.021 to 0.473 across the tumor subtypes (mean ± SD: 0.145 ± 0.164), and a lactate signal was observed in all of the grade 3 tumors. The LAC/PYR was significantly correlated with tumor volume (R = 0.903, P = 0.005) and MCT 1 (R = 0.85, P = 0.032) and HIF1α expression (R = 0.83, P = 0.043). Imaging of hyperpolarized [1-13C]pyruvate metabolism in breast cancer is feasible and demonstrated significant intertumoral and intratumoral metabolic heterogeneity, where lactate labeling correlated with MCT1 expression and hypoxia.

Situação dos extintores de incêndio em estabelecimentos comerciais do município de Vitória da Conquista, Bahia / Contidition of fire extinghishers in some commercial buildings in the municipality of Vitória da Conquista, Bahia / Situación de los extintores de incendio de establecimientos comerciales del municipio de Vitória da Conquista, Bahia

Fogo é necessário para a humanidade, entretanto, muitas vezes, fica fora de controle e passa a ser um agente causador de incêndios, destruição do meio ambiente e mortes, seja na área urbana ou na área rural. Os extintores de incêndio são aparelhos destinados a combater o princípio de incêndio. O objetivo deste estudo foi verificar, nos estabelecimentos comerciais de Vitória da Conquista, Bahia, Brasil, se os extintores portáteis de combate a incêndio estão instalados de acordo com as normas vigentes de proteção, enfatizando a instalação, a visibilidade e se estão desobstruídos. Trata-se de um estudo exploratório descritivo, com abordagem qualitativa, executado mediante a técnica de observação, que envolveu 30 estabelecimentos comerciais. Utilizou-se a técnica de observação descritiva, por ser uma importante fonte de coleta de informações sobre o objeto de análise proposto ­ os extintores portáteis de incêndio. Os resultados mostraram que todos os estabelecimentos comerciais observados tinham extintores. Todos eles (100%) estavam obstruídos e 80% sem sinalização. Concluiu-se que os extintores de incêndio dos 30 estabelecimentos comerciais de Vitória da Conquista encontravam-se em desacordo com as normas vigentes, no tocante à instalação, localização, sinalização, visibilidade e desobstrução.

Fire is a necessity to mankind. However, fire is also a threat because when out of control it causes deaths, destructions and damages to rural and urban environments. Fire extinguishers are equipment used to fight the beginning of fire. The objective of this study was to verify whether the portabel fire extinguishers installed in the commercial buildings of Vitória da Conquista, Bahia, Brasil are in compliance to regulatory norms with emphasis on installation, visibility and unblock aspects. It´s a descriptive exploratory study with a qualitative approach, executed through the technique of observation, comprising 30 commercial buildings. It was used the technique of descriptive observation because this is an important source of information collection about the subject under analysis - portable fire extinguishers. The results shows that all observed commercial buildings have extinguishers installed. All of them (100%) were obstructed and 80% have no indication of safety sign. It was possible to conclude that the fire extinguishers of the 30 commercial establishments of Vitória da Conquista were not compliance to regulatory norms regarding installation, localization, signalization, visibility and unblock.

Fuego es necesario para la humanidad, todavía, cuando fuera de control, provoca incendios, destrucción del medio ambiente y muertes tanto en áreas urbanas como rurales. Los extintores son aparatos que se destinan al combate del principio de incendio. El objetivo de este trabajo fue averiguar en los establecimientos comerciales de Vitória da Conquista, Bahia, Brasil, si los extintores portátiles de combate a incendio están instalados en consonancia con las normas reglamentares, con énfasis en aspectos relacionados con la instalación, con la visibilidad y con la desobstrucción. Tratase de un estudio exploratorio descriptivo, con abordaje cualitativo, ejecutado mediante la técnica de observación, que envolvió 30 estabelecimientos comerciales. Fue utilizada la técnica de observación descriptiva por ser una importante fuente de recopilación de informaciones sobre el objeto de análisis propuesto ­ los extintores portátiles de incendio. Los resultados muestran que todos los estabelecimientos comerciales observados tenían extintores. Pero, el 100% de estos estaban obstruidos y el 80% no estaban señalizados. Concluyóse que la los extintores de incendio de los 30 establecimientos comerciales de Vitória da Conquista estaban en desacuerdo con las normas reglamentares en lo que se refiere a la instalación, localización, señalización, visibilidad y desobstrucción.

Waist circumference as a mediator of biological maturation effect on the motor coordination in children / Perímetro de cintura como mediador da influência da maturação biológica no desempenho de coordenação motora em crianças

Abstract Objective: The present study aimed to: 1) examine the association of biological maturation effect on performance at a motor coordination battery and 2) to assess whether the association between biological maturation and scores obtained in motor coordination tests is mediated by some anthropometric measurement. Methods: The convenience sample consisted of 73 male children aged 8 years old. Anthropometric data considered the height, body mass, sitting height, waist circumference, body mass index, fat mass and fat-free mass estimates. Biological maturation was assessed by the percentage of the predicted mature stature. Motor coordination was tested by the Körperkoordinationstest für Kinder. A partial correlation between anthropometric measurements, z-score of maturation and the motor coordination tests were performed, controlling for chronological age. Finally, causal mediation analysis was performed. Results: Height, body mass, waist circumference and fat mass showed a slight to moderate inverse correlation with motor coordination. Biological maturation was significantly associated with the balance test with backward walking (r=-0.34). Total mediation of the waist circumference was identified in the association between biological maturation and balance test with backward walking (77%). Conclusions: We identified an association between biological maturation and KTK test performance in male children and also verified that there is mediation of waist circumference. It is recommended that studies be carried out with female individuals and at other age ranges.

Resumo Objetivo: O presente estudo teve como objetivos: 1) analisar a associação do estado maturacional com o desempenho nas provas de coordenação motora em crianças e 2) examinar se a relação entre o estado maturacional e o desempenho no KTK é mediada por alguma medida antropométrica. Métodos: A amostra de conveniência foi composta por 73 crianças do sexo masculino com 8 anos. A antropometria considerou a estatura, massa corporal, altura sentado, o perímetro de cintura, índice de massa corporal, as estimativas de massa gorda e massa livre de gordura. A maturação biológica foi avaliada pelo percentual da estatura matura predita. A coordenação motora foi testada pela bateria Körperkoordinationstest für Kinder. Foi feita a correlação parcial entre as medidas antropométricas, z-escore da maturação e as provas de coordenação motora, com controle para idade cronológica. Por último, a análise de mediação causal foi feita. Resultados: Estatura, massa corporal, perímetro de cintura e massa gorda apresentaram correlação inversa de magnitude pequena a moderada com as provas de coordenação motora. A maturação biológica associou-se significativamente à prova de equilíbrio em marcha à retaguarda (r=-0,34). Foi identificada mediação total do perímetro de cintura na relação do estado maturacional com o equilíbrio em marcha à retaguarda (77%). Conclusões: Foi possível identificar a associação entre o estado físico maturacional e o desempenho em uma prova de bateria de coordenação motora em crianças do sexo masculino e, ainda, afirmar que há mediação do perímetro de cintura. Recomenda-se que estudos sejam feitos com indivíduos de outras idades e do sexo feminino.

Perímetro abdominal: evidências para a predição da gordura corporal subcutânea em meninos escolares / Abdominal girth: evidence for the prediction of subcutaneous body fat in student boys

Introdução: O diagnóstico de sobrepeso e obesidade pode ser realizado pela antropometria, por facilidade de execução e baixo custo. Considerando a preocupação com a característica de distribuição de gordura, novas estratégias poderiam ser desenvolvidas para a avaliação da composição corporal partindo de medidas antropométricas. Objetivos: Verificar a correlação do Perímetro Abdominal (PAB) e Perímetro da Cintura (PC) em separado, com o somatório de duas dobras cutâneas (DC), triciptal e subescapular; e incluir o perímetro com os maiores valores de correlação em uma equação de regressão para estimativa do somatório de DC. Métodos: Amostra composta por 1.729 meninos (9 e 14 anos), a avaliação da morfologia corporal foi realizada por medidas antropométricas simples e compostas. Foi utilizada uma correlação de Spearman para determinar a associação entre os PAB e PC com as DC. Foi feita uma análise de regressão linear múltipla com o PAB e idade para estimar o somatório de DC. Resultados: A seguinte equação foi gerada: Somatório de DC = 1,16397 (PAB) ­ 1,414922 (Idade) ­ 36,33021 (R=0,83). O valor da área sob a curva ROC (AUC) foi de 83% para identificar corretamente indivíduos abaixo ou acima do percentil 85 do somatório de DC. Conclusões: O PAB em conjunto com a idade, se torna um bom preditor da gordura corporal, caracterizada como o somatório de DC, em crianças e adolescentes do sexo masculino.

Introduction: The diagnosis of overweight and obesity can be accomplished by anthropometry, for ease of implementation and low cost. Considering the concern for the distribution of fat, new strategies could be developed for the diagnosis of body composition from anthropometric measurements. Objectives: To investigate the association of the abdominal girth (AG) and waist girth (WG) separately, with the sum of two skinfolds (SF), triceps and subscapular; and include the girth with higher correlation levels in a regression equation to estimate the SF sum. Methods: A sample of 1,729 boys (9 and 14), the evaluation of body composition was composed by simple and compound anthropometric measurements. The Spearman correlation was used to determine the association between AG and WG with the sum of SF. A multiple linear regression was applied including AG and age to estimate the sum of SF. Results: The following equation was generated: Sum of SF = 1.16397 (AG) - 1.414922 (age) - 36.33021 (R = 0.83). The area under the ROC curve (AUC) was 83% for correctly identifying individuals below or above the 85th percentile of the SF sum. Conclusions: AG, together with age, becomes a good predictor of body fat, characterized as the sum of two SF in children and adolescent males.