British Journal of Radiology最新文献

Cardiovascular magnetic resonance (CMR) can comprehensively assess cardiac function and structure, with a unique capability for tissue characterisation. However, its access remains limited due to general availability. Additionally, CMR has lengthy preparation and acquisition times. Various optimisation methods and techniques have been proposed to streamline CMR workflow and shorten total acquisition times. These include patient preparation, rapid imaging protocols, sequences developments, deep learning-based image acceleration and reconstruction, as well as automated image analysis and report generation. Together, these advances may grant CMR access to more patients and even enable more accessible non-invasive cardiac screening of high-risk and general population in the future. This narrative review provides an overview of different concepts and technologies aiming at optimising CMR in terms of workflow and image acquisition and highlights the opportunities for high-volume CMR studies to support more patient-centred cardiovascular care.

Background: To evaluate the diagnostic performance of tin-filtered 150 kV ultra-low dose CT (ULDCT) for pulmonary nodule detection and size measurement compared with standard-dose CT (SDCT).

Methods: This prospective study enrolled 261 patients who underwent both SDCT (120 kV) and ULDCT (150 kV with 0.6 mm tin filtration) during a single visit. Radiation dose parameters, subjective and objective image quality, and diagnostic performance were assessed using SDCT as the reference standard. Nodules were classified as solid, pure ground-glass (pGGNs), or mixed ground-glass nodules (mGGNs), and nodule diameters were compared between the two protocols.

Results: ULDCT reduced radiation dose by 83% compared to SDCT (1.10 ± 0.22 mSv vs 6.55 ± 1.51 mSv, P < 0.001) while maintaining excellent image quality. SDCT detected 856 nodules, with ULDCT identifying 779 true-positive nodules. Subtype analysis revealed sensitivities of 99.65% for solid nodules, 100% for mixed ground-glass nodules, and 70.12% for pure ground-glass nodules. No significant differences were observed in nodule diameter measurements between ULDCT and SDCT (P > 0.05).

Conclusions: Tin-filtered 150 kV ULDCT achieves high sensitivity for pulmonary nodule detection with significantly reduced radiation dose and maintain clinically acceptable image quality.

Advances in knowledge: This study provides clinical validation of tin-filtered 150 kV ULDCT in a heterogeneous outpatient population, demonstrating its feasibility for accurate pulmonary nodule detection beyond screening settings and highlighting its subtype-specific performance.

Background and purpose: Deep inspiration breath-hold (DIBH) is commonly used in breast cancer radiotherapy to reduce radiation exposure to the heart and lungs. Recent techniques incorporating oxygen supplementation and hyperventilation have enabled DIBHs exceeding 2.5 minutes. However, data on internal organ st ability during prolonged breath-holds (L-DIBH) remain limited.

Materials and methods: In this prospective observational physiological study, ten healthy female volunteers performed two L-DIBHs (2 minutes 8 seconds each) in both prone and supine positions, following a validated hyperventilation and oxygenation protocol. Serial 3D MRI scans were acquired every 16 seconds during each L-DIBH to assess positional stability of the heart, lungs, and left-sided breast. Cumulative distance-volume histograms (cDiVHs) were used to evaluate spatial relationships between organs and quantify internal displacement over time.

Results: 319 high-quality 3D MRI series were analysed. cDiVHs demonstrated consistent organ positions across timepoints and sessions. While left breast position remained stable throughout all L-DIBHs, minor but statistically significant heart displacement was observed during each L-DIBH increasing over time, more pronounced in the prone position than supine.

Conclusion: L-DIBHs of 2 minutes and 8 seconds are achievable and demonstrate stability in left breast positioning, with minimal movement of adjacent internal organs. Small but progressive shifts of the portion of the heart nearest the breast were detected, particularly in prone positioning.

Advances in knowledge: To account for these minimal displacements during L-DIBH, asymmetrical safety margins around the heart of 3 mm in prone and 2 mm in supine positions may be appropriate.

Objectives: This study evaluated the effectiveness of whole-volume apparent diffusion coefficient (ADC) histogram analysis for stratifying renal allograft function.

Methods: A retrospective analysis included 85 renal transplant recipients with ADC measurements from May 2019 to February 2024. They were divided into three groups based on estimated glomerular filtration rate (eGFR): normal graft function (nRAF, eGFR > 60 mL/min/1.73 m2), mild to moderate graft injury (mRAI, 30 mL/min/1.73 m2≤eGFR ≤ 60 mL/min/1.73 m2), and severe allograft injury (sRAI, eGFR < 30 mL/min/1.73 m2). Receiver operating characteristic (ROC) analysis compared the ability of histogram features to differentiate these groups. Correlations between time since transplantation and histogram features were also evaluated.

Results: Sixteen ADC-based histogram features were extracted. Eight parameters were valuable for assessing renal dysfunction (|r|≥0.3, P < 0.05). Seven parameters-ADCmean and Percentiles (10th, 25th, 50th, 75th, 90th, and 95th)-differed significantly between nRAF and sRAI (P < 0.05), with the 50th percentile yielding the largest area under the curve (AUC = 0.785; 95% CI: 0.624-0.928). Two parameters (10th and 25th percentiles) differed significantly between nRAF and mRAI (P < 0.05), with the 10th percentile achieving the largest AUC (0.684; 95% CI: 0.560-0.808). The 10th percentile was negatively correlated with time since transplantation.

Conclusions: ADC-based histogram analysis effectively stratifies renal allograft function and can be used for long-term monitoring of kidney transplant patients in clinical practice.

Advances in knowledge: This study shows that ADC-based histogram analysis can distinguish different degrees of renal allograft dysfunction and is sensitive to early and chronic renal function changes. It offers a non-invasive method for long-term monitoring of kidney transplant patients.

Artificial intelligence (AI) holds great promise for advancing diagnostics and treatment in nuclear medicine. The rapid growth of AI over the past decade largely driven by advances in hardware components such as graphics processing units (GPUs) and the introduction of Deep Learning (DL) and convolutional neural networks (CNN). The integration of AI and medical imaging has the potential to revolutionize nuclear medicine by, e.g., accelerating image acquisition, enhancing image quality, enabling advanced image generation, assisting image interpretation, and aiding treatment planning. Clinical applications have been demonstrated for most medical specialties, including oncology, neurology and radionuclide therapy. The utilization of AI to provide automated, standardized procedures can help bring advanced imaging from major university centers to smaller local clinics, thus benefiting a broader range of patients. Additionally, AI has vast potential for predicting optimal treatment strategies, assessing risk, optimizing patient flow and outcome, and even improving productivity, but these capabilities have yet to be fully utilized. The fraction of clinical AI applications in general healthcare reaching beyond the prototyping phase are reported as low as 2% [1]. Indeed, in nuclear medicine very few AI developments have reached commercial maturity. Currently, most AI applications in nuclear medicine follow the imaging flow from image acquisition and reconstruction, post-processing and image preparation, image analysis, and decision support for clinical interpretation. Below we will briefly review selected areas and comment on challenges and opportunities for AI in nuclear medicine, with a special focus on the transition from development to clinical implementation.

Objectives: FLASH radiotherapy (FLASH-RT), characterized by ultra-high dose rate irradiation (>40 Gy/s), has demonstrated the potential to spare normal tissues while maintaining tumor control. Most proton and electron FLASH studies have focused on whole-organ irradiation, and the normal tissue-sparing effects of high-dose proton FLASH-RT in localized thoracic settings remain unclear.

Methods: A preclinical mouse model was developed to evaluate localized high-dose (60 Gy) proton FLASH irradiation to the left lung using spot-size transmission at FLASH (500 Gy/s) or conventional (2 Gy/s) dose rates. Lung and skin responses were assessed by histology, flow cytometry, and enzyme-linked immunosorbent assays.

Results: FLASH-irradiated lungs exhibited decreased pneumonitis and fibrosis compared to conventional irradiation, with faster resolution of tissue damage. Skin toxicity, including epidermal thickening and dermal fibrosis, was significantly reduced after FLASH-RT. At the molecular level, FLASH-RT reduced oxidative stress and inflammatory injury, demonstrated by lower Nrf2 activation, reduced 8-OHdG levels, and decreased MPO expression. Systemically, FLASH-RT led to lower neutrophil-to-lymphocyte ratios and decreased serum IL-6, TNF-α, and IFN-γ, indicating reduced inflammation.

Conclusions: Our findings provide the first evidence that proton FLASH-RT at ablative dose levels (>60 Gy) confers localized protection against radiation-induced lung and skin injury in a preclinical setting. These results support the potential of high-dose proton FLASH-RT for thoracic application, though further studies are needed to establish dose-response relationships and optimize clinical beam configurations.

Advances in knowledge: High-dose proton FLASH-RT preserves lung and skin, and mitigates oxidative and inflammatory responses, offering insights into mechanisms underlying the FLASH effect.

Objectives: Given the heterogeneous nature of Alzheimer's Disease (AD) and its higher prevalence in females, it is crucial to understand sex-related differences in AD presentation and changes in the brain.

Methods: : This systematic review investigates sex differences in AD and summarizes key findings from neuroimaging studies over the past two decades to examine how genetics, hormones, and lifestyle factors influence neuroimaging biomarkers and their correlation with cognitive decline and AD progression. A comprehensive literature search was conducted across several databases for human studies from 2004 to 2024 related to AD, biological sex differences, and neuroimaging.

Results: : After a three-step review process, the final extraction included 120 peer-reviewed studies using various neuroimaging modalities, such as Magnetic Resonance Imaging (MRI), amyloid-beta Positron Emission Tomography (PET), tau-PET, and Fluorodeoxyglucose (FDG) PET, to investigate sex as a biological predictor variable in adults with or at risk for AD. Over 90% of the reviewed studies identified clear sex-specific patterns of imaging biomarkers related to cognitive reserve, hormonal changes, APOE-ɛ4 genotype, inflammation, vascular health, and lifestyle factors. Machine learning studies increasingly incorporate sex as a key variable, revealing sex-specific biomarkers and improving model performance in predicting disease status and progression.

Conclusions: Considering biological sex in AD research is essential for improving diagnostic accuracy, tailoring interventions, and health outcomes.

Advances in knowledge: This systematic review identifies sex-specific patterns in neuroimaging biomarkers of Alzheimer's Disease, influenced by cognitive reserve, hormones, APOE-ɛ4 genotype, inflammation, vascular health, and lifestyle. Recognizing these differences is crucial for understanding, diagnosis, and treatment efficacy.

Interventional oncology has gained a lot of traction as an attractive alternative treatment for various musculoskeletal tumors by offering minimally invasive image-guided therapies. In this domain, thermal ablation is increasingly being used malignant tumors, including bone metastatic disease. Thermal ablation therapies such as radiofrequency ablation, microwave ablation, cryoablation and high intensity focused ultrasound therapy achieve excellent local tumor control and pain palliation, whilst structural stability is ensured through the combination with bone augmentation techniques such as standard or reinforced osteoplasty. Many factors are affecting the results including the biology of the disease the treatment intent (curative or palliative) as well as the potential for complications, like thermal injury to surrounding tissues, highlight the need for meticulous procedural planning. This review highlights the pathophysiology, the current repertoire of thermal ablation techniques, clinical outcomes and the future directions for the treatment of metastatic bone disease.