Due to the widespread application in medicine and industry of anthropogenic gadolinium (Gdanth), the widespread of Gd anomaly in surface water has leading to disruption of the natural Gd geochemical cycle. However, challenges related to the identification and quantification of Gdanth, assessment of its impacts on marine ecosystems, and exploration of strategies for mitigating its adverse effects still exist. Meanwhile, as the major source of the Gdanth, the environmental geochemical behavior of Gd-based contrast agents (GBCAs), which are used in medical diagnostics in magnetic resonance imaging (MRI), are still poorly understood. In this review, we 1) analyzed Gd anomalies in samples from published literature worldwide, confirmed their prevalence (81.25% for sea and lake water, 72.73% for river water), 2) demonstrated that the third-order polynomial method is the preferred approach for the detection of Gdanth in surface seawater, 3) outlined the species and applications of Gdanth and its impacts on marine environment, 4) explored the process of GBCAs influx into the ocean and demonstrated the concentration of Gdanth in coral samples was mainly affected by terrestrial input GBCAs (63.75%) through Pearson correlation analysis and principle component analysis, 5) proposed effective management strategies for GBCAs at all stages from production to release into the ocean, 6) formulated an expectation for future research on marine Gdanth.

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BACKGROUND: We prospectively assessed the reproducibility of a novel low-dose single-volume dynamic computed tomography (CT) myocardial blood flow measurement technique.
METHODS: Thirty-four pairs of measurements were made under rest and stress conditions in 13 swine (54.3 ± 12.3 kg). One or two acquisition pairs were acquired in each animal with a 10-min delay between each pair. Contrast (370 mgI/mL; 0.5 mL/kg) and a diluted contrast/saline chaser (0.5 mL/kg; 30:70 contrast/saline) were injected peripherally at 5 mL/s, followed by bolus tracking and acquisition of a single volume scan (100 kVp; 200 mA) with a 320-slice CT scanner. Bolus tracking and single volume scan data were used to derive perfusion in mL/min/g using a first-pass analysis model; the coronary perfusion territories of the left anterior descending (LAD), left circumflex (LCx), and right coronary artery (RCA) were automatically assigned using a previously validated minimum-cost path technique. The reproducibility of CT myocardial perfusion measurement within the LAD, LCx, RCA, and the whole myocardium was assessed via regression analysis. The average CT dose index (CTDI) of perfusion measurement was recorded.
RESULTS: The repeated first (Pmyo1) and second (Pmyo2) single-volume CT perfusion measurements were related by Pmyo2 = 1.01Pmyo1 - 0.03(ρ = 0.96; RMSE = 0.08 mL/min/g; RMSE = 0.07 mL/min/g) for the whole myocardium, and by Preg2 = 0.86Preg1 + 0.13(ρ = 0.87; RMSE = 0.31 mL/min/g; RMSE = 0.29 mL/min/g) for the LAD, LCx, and RCA perfusion territories. The average CTDI of the single-volume CT perfusion measurement was 10.5 mGy.
CONCLUSIONS: The single-volume CT blood flow measurement technique provides reproducible low-dose myocardial perfusion measurement using only bolus tracking data and a single whole-heart volume scan.
CONCLUSIONS: The single-volume CT blood flow measurement technique is a noninvasive tool that reproducibly measures myocardial perfusion and provides coronary CT angiograms, allowing for simultaneous anatomic-physiologic assessment of myocardial ischemia.
CONCLUSIONS: A low-dose single-volume dynamic CT myocardial blood flow measurement technique is reproducible. Motion misregistration artifacts are eliminated using a single-volume CT perfusion technique. This technique enables combined anatomic-physiologic assessment of coronary artery disease.

Quantification of myocardial scar from late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) images can be facilitated by automated artificial intelligence (AI)-based analysis. However, AI models are susceptible to domain shifts in which the model performance is degraded when applied to data with different characteristics than the original training data. In this study, CycleGAN models were trained to translate local hospital data to the appearance of a public LGE CMR dataset. After domain adaptation, an AI scar quantification pipeline including myocardium segmentation, scar segmentation, and computation of scar burden, previously developed on the public dataset, was evaluated on an external test set including 44 patients clinically assessed for ischemic scar. The mean ± standard deviation Dice similarity coefficients between the manual and AI-predicted segmentations in all patients were similar to those previously reported: 0.76 ± 0.05 for myocardium and 0.75 ± 0.32 for scar, 0.41 ± 0.12 for scar in scans with pathological findings. Bland-Altman analysis showed a mean bias in scar burden percentage of -0.62% with limits of agreement from -8.4% to 7.17%. These results show the feasibility of deploying AI models, trained with public data, for LGE CMR quantification on local clinical data using unsupervised CycleGAN-based domain adaptation. RELEVANCE STATEMENT: Our study demonstrated the possibility of using AI models trained from public databases to be applied to patient data acquired at a specific institution with different acquisition settings, without additional manual labor to obtain further training labels.

OBJECTIVE: To compare the diagnostic performance of CEUS-guided biopsy (CEUS-GB) and ultrasound-guided biopsy (US-GB) in evaluating abdominal and pelvic (abdominopelvic) neoplasms in paediatric patients.
METHODS: Patients aged < 18 years with abdominopelvic tumours who underwent either CEUS-GB or US-GB between April 2005 and May 2022 were retrospectively evaluated. Tumours diagnosed as malignancies by pathology were considered true-positive findings. Benign lesions were identified by pathology or clinical follow-up of at least 6 months. The diagnostic performance of the two groups was compared using propensity score matching (PSM). Complications were also analysed.
RESULTS: The present study included 764 paediatric patients (437 boys; median age, 24 months; interquartile range, 10-60 months); 151 were in the CEUS-GB group, and 613 were in the US-GB group. The sample adequacy rate was 100% (151 of 151) for the CEUS-GB group, which was greater than the 97.4% (597 of 613) for the US-GB group (p < 0.001). The overall diagnostic accuracy of the CEUS-GB group and US-GB group was 98.7% (149 of 151) versus 97.3% (581 of 597) in the total cohort (p = 0.551) and 98.7% (149 of 151) versus 92.7% (140 of 151) in the PSM cohort (p = 0.020). Two patients (0.3%) in the US-GB group experienced complications (Common Terminology Criteria for Adverse Events (CTCAE), grade 1-2) correlated with the biopsy. No adverse reactions occurred in the CEUS-GB group.
CONCLUSIONS: CEUS-GB of abdominopelvic tumours in paediatric patients is an effective and safe procedure with greater diagnostic accuracy than US-GB, especially for tumours with necrotic areas.
CONCLUSIONS: Contrast-enhanced US-guided biopsy of solid abdominal and pelvic tumours in paediatric patients is an effective and safe procedure with greater diagnostic accuracy than US-guided biopsy, especially for tumours with necrotic areas.
CONCLUSIONS: Contrast-enhanced ultrasound (CEUS) may be superior to conventional ultrasound at guiding biopsy of abdominopelvic masses in paediatric patients. CEUS-guided core needle biopsy of abdominopelvic masses in children was safe and resulted in a diagnostic yield of 98.7%. CEUS guidance should be considered in this population when colour Doppler US is unable to determine a biopsy site.

OBJECTIVE: This retrospective study aimed to compare the average glandular dose (AGD) per acquisition in breast biopsies guided by contrast-enhanced mammography (CEM), conventional stereotactic breast biopsy (SBB), and digital breast tomosynthesis (DBT). The study also investigated the influence of compressed breast thickness (CBT) and density on AGD. Furthermore, the study aimed to estimate the AGD per procedure for each guidance modality.
METHODS: The study included 163 female patients (mean age 57 ± 10 years) who underwent mammography-guided biopsies using SBB (9%), DBT (65%), or CEM (26%) guidance. AGD and CBT data were extracted from DICOM headers, and breast density was visually assessed. Statistical analyses included two-sample t-tests and descriptive statistics.
RESULTS: Mean AGD per acquisition varied slightly among CEM (1.48 ± 0.22 mGy), SBB (1.49 ± 0.40 mGy), and DBT (1.55 ± 0.47 mGy), with CEM presenting higher AGD at lower CBTs and less dose escalation at higher CBTs. For CBT > 55 mm, CEM showed reduced AGD compared to SBB and DBT (p < 0.001). Breast density had minimal impact on AGD, except for category A. The estimated AGD per procedure was approximately 11.84 mGy for CEM, 11.92 mGy for SBB, and 6.2 mGy for DBT.
CONCLUSIONS: The study found mean AGD per acquisition to be similar for CEM and SBB, with DBT slightly higher. CEM demonstrated higher AGD at lower CBT but lower AGD at higher CBT, indicating reduced dose escalation with increasing thickness. While breast density had minimal overall impact, variations were noted in category A. DBT was more dose-efficient per procedure due to fewer acquisitions required.
CONCLUSIONS: CEM guidance provides effective lesion visualization within safe radiation limits, improving the precision of percutaneous image-guided breast interventions and supporting its potential consideration in a wider range of breast diagnostic procedures.
CONCLUSIONS: Limited data exist on the AGD using CEM guidance for breast biopsies. CEM and SBB exhibit similar AGD per acquisition; DBT demonstrated the lowest AGD per procedure. Radiation from CEM guidance fits within safe limits for percutaneous image-guided breast interventions.

This study aimed to evaluate the impact of contrast media application on CT attenuation of the bone using a novel calcium-only imaging technique (VCa) from dual-layer spectral detector CT (DLCT), which enables CT-based bone mineral density measurement unimpeded by soft tissue components. For this, true non-contrast (TNC) and venous phase images (VP) of n = 97 patients were acquired. CT attenuation of the first lumbar vertebra (L1) was measured in TNC-VCa, VP-VCa, and in virtual non-contrast images (VNC). CT attenuation was significantly higher in VP-VCa than in TNC-VCa (p < 0.001), although regression analyses revealed a strong linear association between these measures (R2 = 0.84). A statistical model for the prediction of TNC-VCa CT attenuation was established (TNC-VCa[HU] = - 6.81 + 0.87 × VP-VCa[HU]-0.55 × body weight[kg]) and yielded good agreement between observed and predicted values. Furthermore, a L1 CT attenuation threshold of 293 HU in VP-VCa showed a sensitivity of 90% and a specificity of 96% for detecting osteoporosis. The application of contrast media leads to an overestimation of L1 CT attenuation in VCa. However, CT attenuation values from VP-VCa can be used within CT-based opportunistic osteoporosis screening eighter by applying a separate threshold of 293 HU or by converting measured data to TNC-VCa CT attenuation with the given regression equation.

Contrast ultrasound (CUS) has received much interest because of its sensitivity enhancement for blood flow imaging. However, there is still a lack of nonlinear simulation method for CUS, as conventional simulators cannot deal with the microbubble acoustic nonlinearity. In this paper, a nonlinear simulation method of CUS is developed based on a combination strategy of the k-space pseudospectral method and Rayleigh-Plesset Marmottant model. Different contrast pulse sequence strategies as well as the radial modulation imaging are simulated and compared using the proposed method. For blood flow imaging, simulations under different scenarios such as power Doppler and ultrasound localization microscopy are also carried out. Furthermore, a face-to-face comparison is performed between simulations and phantom experiments to validate the proposed method.

Background A watch-and-wait regimen for locally advanced rectal cancer after neoadjuvant chemotherapy and radiation therapy (NCRT) relies on identifying complete tumor response. However, the concordance between a complete response at combined T2-weighted and diffusion-weighted MRI (T2DWI) and pathologic complete response (pCR; ie, ypT0N0) in the tumor is unsatisfactory. Purpose To assess whether identification of mucosal linear enhancement (MLE) at arterial-phase contrast-enhanced (CE) T1-weighted MRI is associated with ypT0 status in patients with locally advanced rectal cancer after NCRT and to evaluate whether combining MLE at CE T1-weighted MRI and negative lymph node metastasis (LNM) at T2DWI can improve identification of pCR. Materials and Methods This retrospective study included patients with locally advanced rectal cancer who underwent total mesorectal excision after NCRT between July 2020 and July 2023 at a tertiary referral academic center. Restaging MRI included T2DWI and arterial-phase CE T1-weighted MRI for primary tumor assessment and T2DWI for evaluation of LNM status. Imaging features associated with ypT0 status were identified at multivariable regression analysis. Results In total, 239 patients (mean age, 58 years ± 12 [SD]; 180 male patients) were assessed. MLE was more common in the ypT0 group than in the ypT1-4 group after NCRT (73% vs 4%, respectively; P < .001). MLE was associated with higher odds of ypT0 status in an adjusted analysis (odds ratio, 137; 95% CI: 25, 767; P < .001). The combination of MLE and negative LNM status achieved an area under the receiver operating characteristic curve of 0.84 (95% CI: 0.79, 0.88) for pCR. Conclusion MLE at CE MRI was associated with higher odds of complete tumor response. Combining MLE and negative LNM status showed good performance for identifying complete tumor response and may exclude residual tumors after NCRT in patients with locally advanced rectal cancer. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Schoellnast in this issue.

Photoacoustic imaging is a hybrid modality that combines high-contrast and spectroscopy-based optical imaging specificity with the high spatial resolution of ultrasonography. This review highlights the development and progress of photoacoustic imaging technology over the past decade. This imaging technology has evolved to be more user-friendly, cost-effective, and portable, demonstrating its potential for diverse clinical applications. A potential clinical application lies in the use of photoacoustic imaging as a guiding tool for photothermal therapy. This review was conducted by initially filtering through three databases, namely, Google Scholar, PubMed, and Scopus, resulting in 460 articles published between 2019 and May 2023. Of these, 54 articles were deemed suitable for review after identification. The selected articles were research papers focusing on the development of therapeutic agents that enhance contrast in photoacoustic imaging. All reviewed articles tested these agents both in vitro and in vivo. This review focuses on wavelength absorption and radiation sources for photothermal therapy. The developed agents predominantly used NIR-I wavelengths, whereas the NIR-II region has been less explored, indicating significant potential for future research. This review provides comprehensive insights into the advancement of compounds serving as therapeutic agents and contrast agents in photoacoustic imaging-guided photothermal therapy.