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- Radiation dose reduction in CT exams with iterative and deep learning reconstruction: A systematic reviewPublication . Coelho, Sandra; Dinis, Maria de Lurdes; Freitas, Marco; Baptista, João SantosThis systematic review evaluated the effectiveness of iterative reconstruction (IR) and deep learning reconstruction (DLR) in reducing radiation dose in computed tomography (CT) while preserving diagnostic image quality. We systematically searched PubMed, Scopus, and Web of Science (last search 22 March 2025); the protocol was registered in the OSF (DOI: 10.17605/OSF.IO/TUQDS). Eligible studies were English-language adult (≥18 years) investigations published between 2020 and 2025 that used IR or DLR and reported radiation-dose outcomes; studies on paediatric, phantom, cadaver, cone-beam, and spectral CT were excluded. In accordance with PRISMA 2020 guidelines, 4371 records were identified, and 30 met the inclusion criteria. Risk of bias was assessed using the NIH Quality Assessment Tool; most studies were deemed to be at low risk. Data were narratively synthesised and structured by a reconstruction approach and anatomical region. Across the 30 studies, IR achieved a dose reduction of 24–50% (mean ≈ 45%) and a DLR reduction of 34–89% (mean ≈ 58%); several DLR protocols enabled reductions of ≥75% without impairing diagnostic quality. Thirty studies in total were included (total N = 2581; range 24–289). It was determined that both approaches substantially reduce radiation exposure while maintaining diagnostic image quality; DLR generally demonstrates greater noise suppression and dose efficiency, especially in ultra-low-dose applications. However, heterogeneity in methods, designs, and scanner technologies limits the ability to draw uniform conclusions. Standardised protocols, multi-vendor prospective studies, and longterm evaluations are needed.
- Detection of physiological changes in knee cartilage using parametric T2 relaxation maps estimated with a dictionary methodPublication . Coelho, José M.; Fernandes, Tiago T.; Alves, Sandra M.; Vilaça, Adélio; Nunes, Rita G.; Nogueira, Luísa; Oliveira, António; Nogueira, Luisa; Alves, Sandra MariaTo investigate half-marathon running and recovery effects on knee articular cartilage (KAC) health in athletes, using dictionary-matching T2 maps, to detect changes and recovery patterns in KAC. Eleven asymptomatic volunteers (4 females, 7 males; mean age 40 ± 5 years, mean BMI 22.7 ± 1.4 kg/m2) completed a fixed-pace half-marathonwere studied. All were right-knee dominant and engaged in regular running. Sagittal T2-weighted Multi-Echo Spin-Echo images at 3 T were used to assess T2 values pre-run, post-run, and one week later for global and compartmental KAC. Recovery programme included low-intensity running, strength training and rest. Repeated measures ANOVA or equivalent non-parametric tests with post-hoc comparisons compared T2 values over time. Separate analyses were conducted based on laterality, gender and anatomical compartments. Significance was set at < 0.05. Post-run T2 values decreased significantly by 0.9 ms (− 2.0%, p < 0.001), with up to 5.3% reductions in medial tibial (MT) and femoral (MF) compartments. Recovery patterns varied by compartment, sex and laterality. Most compartments returned to baseline within one week; the lateral condyle (LatC) showed incomplete recovery (− 4.7%, Proportional Recovery Index (PRI) = − 0,1); the right knee’s MT exhibited overcompensation (6.3%, PRI = 2.6). Males showed higher baseline T2 values and more efficient recovery in the LatC compared to females (PRI = − 0.1 vs. − 0.4). Half-marathon running induces reversible reductions in KAC hydration, with most compartments recovering or overcompensating within one week. Dictionary-matching T2 mapping offers a robust approach for monitoring cartilage integrity and guiding individualised recovery strategies.
- Assessment of fat mass and fat-free mass in Portuguese adults: calibration of single-frequency leg-to-leg bioelectrical impedance with dual-energy x-ray absorptiometryPublication . Farias, Fernanda; Severo, Milton; Ramos, Elisabete; Lopes, Carla; Nogueira, Luísa; Araújo, Joana; Nogueira, LuisaBioelectrical impedance analysis (BIA) is more commonly employed in outpatient evaluations and epidemiological studies as it is cheaper and less time-consuming. Therefore, we aimed to compare fat mass (FM) and fat-free mass (FFM) estimated by BIA and dual-energy x-ray absorptiometry (DXA) in Portuguese adults, and to calibrate BIA estimates. We analyzed data from two population-based cohorts: EPIPorto (n = 391; <65 y) and EPITeen (n = 973; 27 y). Both completed single-frequency leg-to-leg BIA (Tanita TBF-300) and DXA (QDR 4500A Hologic). Agreement between BIA and DXA (FM/FFM) was evaluated by Bland and Altman. To calibrate the BIA estimates, the coefficients were estimated by linear regression using univariate (FM or FFM, separately) and multivariate models (FM and FFM in the same model). The correlation between BIA and DXA was high for FFM and for FM (FFM: r = 0.946/r = 0.954; FM: r = 0.926/r = 0.921, for EPIPorto and EPITeen, respectively). However, BIA underestimated FM (19.4% EPIPorto; 24.3% EPITeen) and overestimated FFM (11.3% EPIPorto; 14.4% EPITeen). Using the multivariate constrained model to have an absolute equal intercept for FFM and FM, the following calibration equations for BIA measurements were obtained for EPIPorto: FFMcalibrated =-5.119 + 0.995 £ FFMBIA;FMcalibrated = +5.119 + 0.980 £ FMBIA; and for EPITeen: FFMcalibrated =-5.707 + 0.984 £ FFMBIA;FMcalibrated = +5.707 + 0.975 £ FMBIA. FM assessed by single-frequency leg-to-leg BIA was largely underestimated and FFM overestimated in comparison to DXA, suggesting the use of BIA model-specific calibration equations to calibrate FM and FFMestimates in clinical settings and research studies.
- Changing slopes: can we be moving toward improved early treatment response prediction in breast cancer?Publication . Nogueira, Luísa; Adubeiro, Nuno; Nunes, Rita G.; Nogueira, LuisaBreast cancer is the most common malignant cancer among women worldwide. For locally advanced disease and selected early-stage cases of human epidermal growth factor receptor 2 (HER-2)-positive and triple-negative breast cancers (TNBC), neoadjuvant chemotherapy (NAC) is the standard of care. NAC reduces tumor burden, facilitates axillary surgery de-escalation, increases the feasibility of breast-conserving surgery and aims to achieve a pathological complete response (pCR). Attaining pCR after NAC is associated with improved disease-free and overall survival rates, providing valuable prognostic information.
- Osseodensification vs. Conventional Osteotomy: A case series with cone beam computed tomographyPublication . Costa, José Adriano; Mendes, José Manuel; Salazar, Filomena; Pacheco, José Júlio; Rompante, Paulo; Moreira, Joaquim Ferreira; Mesquita, José Diogo; Adubeiro, Nuno; Câmara, Marco Infante daOsseodensification is a non-extraction technique using specially designed drills to increase bone density while extending an osteotomy, allowing bone to be preserved and condensed by compacting autograft during osteotomy preparation, increasing bone density around implants, and improving mechanical stability. The objective of this study is to compare conventional osteotomy and osseodensification protocols in implant placement and analyze whether there are differences in bone density. Study variables were defined, namely, osseodensification technique, conventional osteotomy technique, bone density, sex, area of location, implant dimensions, implant dimensions, and implant stability. Eligibility and exclusion criteria were defined. A step-by-step surgical protocol was developed. The surgeon and radiologist underwent intra-examiner calibration. A total of 15 patients were selected according to the eligibility criteria, and a total of 41 implants were inserted, 20 implants by conventional osteotomy and 21 by osseodensification. A cone beam computed tomography was performed one year after prosthetic rehabilitation to estimate bone density. Data were collected and recorded, and in the analysis of the association of variables, non-parametric tests were applied. Significant statistical results were found in bone density values, with higher values being obtained with the osseodensification technique, that is, median density values of 1020, and median density values of 732 for the bone drilling technique. The results of the correlation between bone density in both techniques and sex, primary implant stability, implant dimensions and location area were statistically non-significant. Within the limitations of this study, there are differences in bone density between conventional osteotomy and osseodensification protocols. Bone density is increased with osseodensification over a study period of one year.
- Contributo para o estabelecimento de níveis de referência de diagnóstico em eletrofisiologia de intervenção: estudo de um centro em PortugalPublication . Videira, Sara; Pereira, José Manuel; Pereira, José ManuelA maioria dos procedimentos eletrofisiologia de intervenção necessitam de fluoroscopia expondo à radiação ionizante todos os intervenientes. O recurso a níveis de referência de diagnóstico (NRD) pode ser uma ferramenta profícua para promover a otimização de dose. O principal objetivo deste estudo consistiu em investigar as doses de exposição, determinando os NRD.
- Investigação aplicada - Aspetos globaisPublication . Aubeiro, Nuno; Adubeiro, NunoO campo da investigação na saúde é inerentemente uma área de extrema complexidade, com muitas particularidades, mas cujo aporte é fulcral para que se possam tomar decisões baseadas na evidência.
- Controlo radiográfico de dispositivos médicos em neonatologiaPublication . Reis, Raquel; Rebelo, Sofia; Pereira, José Manuel; Pereira, José ManuelA gestão clínica dos recém-nascidos nas unidades de cuidados intensivos neonatais implica a colocação de diversos dispositivos médicos invasivos que necessitam de controlo radiográfico. O principal objetivo deste trabalho consistiu em realizar uma revisão narrativa sobre as boas práticas a adotar na aquisição de imagens radiográficas, em unidades de cuidados intensivos neonatais, para o controlo de dispositivos médicos de acordo com a literatura publicada e a experiência dos autores. Realizou-se uma revisão narrativa da literatura. Recorreu-se às bases de dados científicas PubMed; Science Direct; Google Scholar e Portal RCAAP, para a recolha de documentos de análise. Foram, ainda, consultados livros das coleções particulares dos autores. A revisão narrativa incidiu sobre 39 documentos, dos quais 26 artigos científicos, quatro guidelines/consensos/recomendações e nove livros/capítulos de livro. A colocação de cateteres intravasculares, sondas nasogástricas e tubos endotraqueais são procedimentos interventivos habitualmente utilizados na prestação de cuidados a recém-nascidos prematuros internados nas unidades de cuidados intensivos neonatais. O posicionamento preciso destes dispositivos é essencial e a radiografia do tórax e abdómen desempenha um papel de extrema relevância no controlo e monitorização da colocação destes dispositivos. Os desafios técnicos inerentes à realização destes exames radiográficos assumem uma exigência suplementar atendendo aos ajustes ao posicionamento e parâmetros de exposição em relação à população adulta. Os parâmetros de aquisição, bem como o pós-processamento da imagem, deverão ser otimizados de forma a permitirem visualizar o trajeto dos dispositivos médicos em toda a sua extensão e demonstrarem inequivocamente a posição da sua extremidade distal. Ao mesmo tempo a imagem terá de apresentar leitura anatómica suficiente para a monitorização de eventuais lesões iatrogénicas. O célere reconhecimento radiográfico de dispositivos incorretamente colocados, assim como, as complicações que podem originar, é essencial para uma rápida intervenção que permita a prevenção do agravamento do estado clínico do recém-nascido.
- Análise de repetição de exames em radiologia convencionalPublication . Freitas, Artur; Pereira, José Manuel; Pereira, José ManuelA Radiologia Convencional é o método de primeira linha no diagnóstico de diversas patologias e avaliação da anatomia. A repetição de exames relaciona-se com o não cumprimento de critérios de boa realização que resultem em ausência/insuficiência de valor diagnóstico. A diminuição da taxa de repetição representa um fator importante na área da radiologia e da saúde comunitária, contribuindo para a diminuição da dose recebida pelos doentes e profissionais de saúde. O objetivo principal deste estudo foi determinar os exames de radiologia convencional mais suscetíveis de serem repetidos pelos técnicos de radiologia, e causas associadas. Realizou-se um estudo analítico, observacional e transversal. Os dados foram colhidos através da aplicação online de um inquérito por questionário aos participantes no estudo. A população em estudo consistiu em técnicos de radiologia portugueses, licenciados em radiologia ou imagem médica e radioterapia, a exercer funções em Portugal ou no estrangeiro. Para o estudo de associações entre variáveis, utilizaram-se os testes estatísticos de Correlação de Pearson e Qui-quadrado da independência. A amostra foi constituída por 228 participantes, dos quais 176 (77,2%) do sexo feminino, com média de idade de 33.93 (±10.37) anos e tempo médio de experiência profissional de 10.58 (±10.34) anos. O exame ao joelho (61%) foi considerado pelos participantes como o mais provável de ser repetido, seguido do tórax (29.4%) e ombro (24.6%). Os participantes apontaram como erro técnico mais comum o posicionamento incorreto, sendo a não colaboração do doente, o principal fator preditor de erro técnico. Observou-se uma correlação negativa de fraca amplitude entre o tempo de experiência dos profissionais e a frequência com que repetem exames radiológicos. Os exames realizados ao joelho, ombro e tórax, são aqueles que apresentam maior taxa de repetição, sendo o erro mais comum o posicionamento incorreto do doente. O fator que mais contribui para o erro é a não colaboração do doente. Os participantes realçam a necessidade do desenvolvimento de programas de formação contínua e a introdução de pequenas pausas durante os turnos.
- Editorial for “Three‐dimensional multifrequency MR elastography for microvascular invasion and prognosis assessment in Hepatocellular Carcinoma”Publication . Adubeiro, Nuno; Nunes, Rita G.; Nogueira, LuísaThe prognosis of individuals with hepatocellular carcinoma(HCC), the most prevalent primary liver malignancy, is closely linked to the aggressiveness and recurrence of the tumor. The occurrence of complications after surgery continues to be a major and persistent challenge. MR elastography (MRE) employs a modified phase-contrast imaging sequence, combined with the use of an external driver to transmit mechanical vibrations to the tissues, to identify propagating shear waves within the liver. This technique allows the assessment of a substantial portion of the liver and provides information on multiple mechanical properties associated with various pathophysiological states. Due to substantial progress in MR technology, MRE has proven to be a precise noninvasive diagnostic method for detecting and monitoring various liver diseases. MRE imaging could serve as a valuable tool for staging malignancy and predict disease prognosis.