Radionuclide pulmonary ventilation/perfusion (V/Q) imaging is an important non-invasive tool for diagnosing pulmonary thromboembolism (PTE) and is used for screening, follow-up, and assessment of treatment response of PTE and chronic thromboembolic pulmonary hypertension (CTEPH). Currently, hospitals in China differ in their use of planar and tomographic acquisition methods for V/Q imaging, and interpretation requires a high level of expertise among nuclear medicine physicians. After surveying the nuclear medicine departments of multiple hospitals and holding expert discussions, the working group developed the Expert consensus on the operational protocol for radionuclide pulmonary ventilation/perfusion scintigraphy of pulmonary thromboembolism. This consensus covers examination procedures, diagnostic approaches, and precautions, with the aim of standardizing the clinical application of V/Q imaging procedures and their clinical application in PTE diagnosis. The following recommendations were formulated.Summary of RecommendationsRecommendation 1: For ventilation imaging, 99mTc-Technegas is recommended as the preferred radiopharmaceutical. During the preparation of Technegas, the working group recommends wetting the crucible with anhydrous ethanol before the addition of the sodium pertechnetate solution to improve the efficiency and quality of Technegas generation. If Technegas is unavailable, 99mTc-Diethylenetriaminepentaacetic acid (99mTc-DTPA) aerosol may be used as an alternative (Consensus level: 100%).Recommendation 2: Routine supplemental oxygen is suggested before pulmonary perfusion imaging to prevent false-positive images caused by pulmonary vasospasm. The recommended oxygen flow rate is 2-4 L/min, with an inhalation duration of 5-10 minutes (Consensus level: 83.3%).Recommendation 3: For pulmonary perfusion imaging, 200 000-700 000 radiopharmaceutical particles (mean, approximately 400 000) should be administered, with the recommended activity of 120-240 MBq (3-6 mCi). For patients with severe pulmonary hypertension, conditions with right-to-left heart shunting, or a history of single-lung transplantation, the particle number should be reduced to 100 000-200 000 (Consensus level: 83.3%).Recommendation 4: Gently agitate and homogenize the suspension of 99mTc-macroaggregated human serum albumin (99mTc-MAA) prior to injection. With the patient supine and breathing at normal tidal volume, slowly inject the tracer over several respiratory cycles through a patent intravenous line, continuously monitoring for adverse reactions; discontinue immediately if discomfort occurs. Strictly avoid backflow of blood into the syringe, which may cause particulate aggregation and bolus formation, leading to artifactual hot spots (Consensus level: 100%).Recommendation 5: For patients with protein allergies, a routine skin test is recommended before pulmonary perfusion imaging. Inject 0.1 ml of 99mTc-MAA suspension into the appropriate part of the forearm and observe for 15-20 minutes. If there is no positive reaction, perfusion imaging can be proceeded, with close observation and emergency medications on standby. If the skin test is positive, pulmonary perfusion imaging is not recommended. Routine skin testing is not indicated in patients without a history of allergy (Consensus level: 83.3%).Recommendation 6: For the 2-day acquisition protocol, perform pulmonary perfusion imaging on the first day. If the result is abnormal, perform pulmonary ventilation imaging the following day to aid diagnosis; if the perfusion imaging result is normal, pulmonary ventilation imaging may be omitted (Consensus level: 83.3%).Recommendation 7: For pregnant women with suspected PTE, if V/Q imaging is considered necessary after clinical assessment, a 2-day protocol is recommended. Dose reduction is recommended for lung perfusion imaging, the recommended dose of 99mTc-MAA is 50 MBq (1.35 mCi) (Consensus level: 100%).Recommendation 8: When the 1-day acquisition protocol is used, perfusion imaging may be performed immediately after completion of ventilation imaging. To ensure the clarity and accuracy of pulmonary perfusion imaging, the perfusion count rate should be 3-4 times the ventilation count rate (Consensus level: 100%).Recommendation 9: Avoid ambiguous phrasing such as "possible pulmonary embolism" in image reports. Interpretations should provide a definitive conclusion, such as "pulmonary embolism present", "pulmonary embolism absent", or another specific conclusion, after excluding other causes of impaired pulmonary perfusion (e.g., Takayasu arteritis, mediastinitis or pulmonary arterial sarcoma). When the diagnosis remains uncertain, the report should state, "pulmonary embolism cannot be excluded; correlation with clinical findings and other imaging examinations is recommended" to support subsequent clinical assessment and therapeutic decision-making (Consensus level: 100%).Recommendation 10: For patients with CTEPH, visual semi-quantitative analysis (Begic/Meyer score) may serve as an adjunctive tool for efficacy assessment after percutaneous pulmonary balloon angioplasty (BPA) or pulmonary endarterectomy (PEA). Where institutional resources permit, structured reporting is encouraged to improve the clarity and reproducibility of segmental impairment documentation (Consensus level: 100%).

Pediatric osteoporosis is a rare but increasingly recognized entity that differs from adult forms in its etiology, diagnostic criteria, and long-term skeletal implications. Unlike age-related osteoporosis in adults, bone fragility in children is categorized into primary forms, such as osteogenesis imperfecta and the monogenic causes of early-onset osteoporosis, and the more prevalent secondary forms arising from chronic systemic disease, endocrine and nutritional disorders, malignancy and its treatment, prolonged medication use, and immobilization. Early and accurate diagnosis is critical, as failure to achieve optimal peak bone mass during growth can lead to lifelong morbidity. Imaging is central to this process, but interpreting pediatric bone health requires specialized knowledge: results are expressed as Z-scores rather than T-scores, they must be adjusted for body size, and they cannot be inferred from radiographs. While dual-energy X-ray absorptiometry (DXA) remains the reference standard in clinical practice, it measures areal rather than volumetric bone mineral density and is therefore confounded by bone size; quantitative CT and high-resolution peripheral QCT provide volumetric density and microarchitectural information. This review is centered on the practical questions faced by radiologists: how pediatric DXA should be performed, interpreted, and reported; which conditions mimic or overlap with osteoporosis in the diffusely under-mineralized pediatric skeleton; the spectrum of primary and secondary causes; and what radiologists should know about treatment monitoring and follow-up.

Ensuring structural reliability in aerospace and advanced manufacturing demands non-destructive evaluation (NDE) techniques that are both accurate and adaptable. We present a flexible framework based on geometric phase sensing, which captures topological shifts in acoustic fields to characterize internal defects. By integrating broadband excitation with remote sensing methods such as laser Doppler vibrometry, we demonstrate defect localization and tracking using a geometric phase change-index (GPC-I) and extend the method to quantitative pore structure analysis through global geometric phase measurements. Applied to additively manufactured Inconel 718 samples, our approach enables both spatial mapping of defect distributions and quantitative correlation with pore size, pore volume fraction, and pore clustering, as validated by micro-X-ray computed tomography. The method eliminates the need for prior material calibration, enabling real-time, model-free detection and microstructure evaluation under practical manufacturing constraints, offering a path toward scalable, high-fidelity structural health monitoring and quality assurance in complex manufacturing environments.

Noninvasive imaging is the cornerstone in the diagnosis and management of coronary artery disease, which continues to be a leading cause of morbidity and mortality worldwide. Of the modalities available, positron emission tomography/computed tomography and cardiac magnetic resonance have shown the highest accuracy for detecting flow-limiting coronary stenoses. Each modality additionally offers the ability to quantify the myocardial blood flow and myocardial perfusion reserve on a pixel-wise, segmental, and global level. Quantitative perfusion has shown additive diagnostic value over traditional perfusion imaging, particularly in difficult cases such as multivessel disease, and will likely be increasingly found in clinical workflows. This State-of-the-Art Review compares the principles, performance, limitations, and future directions of quantitative myocardial blood flow assessment using positron emission tomography/computed tomography and cardiac magnetic resonance and provides physicians with practical guidance on when to choose which test.

Background Use of virtual noncontrast (VNC) images from photon-counting CT (PCCT) may reduce radiation dose and support quantitative lung analysis by obviating the need for separate true noncontrast (TNC) acquisitions. Their accuracy for lung densitometry, however, has not been systematically assessed. Purpose To evaluate agreement between VNC and TNC images for global and regional lung attenuation measurements in thoracic PCCT. Materials and Methods This retrospective study included patients who underwent same-day unenhanced and contrast-enhanced thoracic PCCT between November 2021 and January 2024. VNC datasets were reconstructed from contrast-enhanced scans. Lung volume, mass, and attenuation were compared using paired t tests, Wilcoxon signed-rank tests, and Bland-Altman analysis. Inspiratory depth effects were assessed with linear regression. Density class distributions were compared, and voxel-wise attenuation differences were evaluated in a subset of patients after nonlinear registration. Results This study included 83 patients (mean age, 60.0 years ± 15.0 [SD]; 47 men). Mean lung volume (4143 mL ± 1375 vs 4111 mL ± 1384; P = .41) and mean attenuation (-799 HU ± 56 vs -798 HU ± 56; P = .91) were similar between VNC and TNC images. After adjustment for inspiratory depth, VNC and TNC images demonstrated no systematic bias, and attenuation differences demonstrated substantially lower variability after adjustment than before adjustment (mean difference, -1.1 HU ± 5.9 vs -0.8 HU ± 19.5), with corresponding 95% limits of agreement of -12.6 to 10.5 HU and -39.1 to 37.5 HU, respectively. Density class analysis demonstrated that emphysematous areas were slightly underestimated (median, -0.4% [IQR, -1.4% to 0.1%]; P < .001) and normal-attenuation lung areas were modestly overestimated (median, +0.8% [IQR, -1.3% to 1.7%]; P < .001) on VNC images, without relevant changes in higher-density classes (both P ≥ .71). Voxel-wise differences were minimal within parenchyma (mean, 0.6 HU ± 15.1; P = .76) but more pronounced at anatomic interfaces. Conclusion In patients who underwent thoracic PCCT, VNC images demonstrated agreement with TNC scans for lung volume and attenuation, and inspiratory depth, rather than reconstruction method, was the dominant source of attenuation variability. © RSNA, 2026 Supplemental material is available for this article.

Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiac disorder and remains associated with sudden cardiac death (SCD), heart failure, and diagnostic uncertainty due to overlap with other causes of left ventricular hypertrophy, including hypertensive heart disease and cardiac amyloidosis. This review aimed to evaluate the evolving applications of radiomics in the context of related quantitative imaging techniques. A review was conducted of studies applying radiomics, texture analysis, machine learning, and deep learning to cardiac imaging in HCM. The evidence base derives predominantly from CMR, with a smaller and more recent body of work in echocardiography and CT. Current evidence suggests that radiomics can extract quantitative features of myocardial texture, shape, and signal heterogeneity beyond visual assessment. These approaches have shown promise in differentiating HCM from phenocopies, identifying myocardial fibrosis without contrast administration, and improving the prediction of adverse outcomes, including SCD and heart failure. Several studies reported incremental value over conventional imaging markers such as wall thickness, global T1 values, and binary late gadolinium enhancement. However, the literature remains limited by retrospective study design, small cohorts, heterogeneity in imaging acquisition and segmentation, and insufficient external validation. Radiomics has emerged as a promising adjunct to conventional cardiac imaging in HCM, with the potential to be adapted into a clinical decision support tool. Its future clinical role will depend on methodological standardization and robust external validation.