Monitoring iohexol and its transformation products as evidence of reclaimed water irrigation input to contiguous waterbodies.

Irrigation with reclaimed water alleviates water supply shortages, but excess application often results in impairment of contiguous waterbodies. This project investigated the potential use of iohexol, an iodinated contrast media used in medical imaging, together with its bio- and phototransformation products as unique reconnaissance markers of reclaimed water irrigation intrusion at three golf courses within the state of Florida. Inter-facility iohexol concentrations measured in reclaimed waters ranged over ~2 orders of magnitude while observed intra-facility seasonal differences were ≤1 order of magnitude. A ~50 % reduction in iohexol was observed post-disinfection for reclaimed water facilities utilizing UV light while none was observed with use of chlorine. Iohexol biotransformation products were observed to decline or shift to lower molecular weight compounds when exposed to UV light but not during disinfection using chlorine. Iohexol biotransformation products were observed in most of the samples but were more prevalent in samples collected during the dry season. Much fewer iohexol phototransformation products were observed in chlorinated reclaimed water, and they were only observed in UV light irradiated reclaimed water when the pre-disinfectant iohexol concentration was ≥5000 ng/L or from solar exposure of reclaimed water spiked with 10 µM of iohexol. For the Hillsborough golf course overlaying an aquifer, the groundwater did not contain iohexol or phototransformation products but did contain biotransformation products. It is not known if these biotransformation products are from active or historical intrusion. The additional presence of sucralose in the aquifer suggests that intrusion has occurred within the past 3 years. This study demonstrates three crucial points in attempting to utilize iohexol to denote reclaimed water intrusion from irrigation overapplication: (1) interpretable results are obtained when iohexol concentrations in the reclaimed water employed for irrigation are ≥1000 ng/L, with higher concentrations in the range of ≥5000 ng/L better able to meet analytical sensitivity requirements after further dilution or degradation in the environment; (2) it is beneficial to assess iohexol transformation products in tandem with iohexol monitoring to account for environmental transformations of iohexol during storage and transport to the receiving water of concern; and (3) inclusion of monitoring for sucralose, an artificial sweetener ubiquitous in wastewater sources that is comparatively stable in the environment, can aid in interpretating whether reclaimed water intrusion based on identification of iohexol and transformation products in the receiving water is attributable to historic or ongoing irrigation overapplications.

Photon-counting detector CT with an ultra-low-dose contrast media to diagnose a renal pseudoaneurysm: A case report.

A 75-year-old male, weighing 71 kg, was admitted to our institution with anemia related to a subcapsular hematoma after accidental extraction of a nephrostomy catheter. While the patient exhibited the progression of chronic kidney disease, he was not yet on dialysis. His serum creatinine level increased to 6.8 mg/dL, with an estimated glomerular filtration rate of 7.4 mL/min/1.73 m2. Radiologists planned contrast-enhanced photon-counting detector CT (PCD-CT) with an ultra-low-dose contrast media to mitigate the impact on renal function. The contrast media dosage was set at 7.4 gI, which was 82.6% lower that used in the standard protocol for a male weighing 71 kg. Non-contrast-enhanced PCD-CT identified a low-density nodular area within the renal subcapsular hematoma. Contrast-enhanced PCD-CT revealed contrast enhancement in both the early and late phases corresponding to the nodular area. On virtual monoenergetic images, the renal pseudoaneurysm was most clearly delineated at 40 keV. Following the diagnosis of a pseudoaneurysm, transcatheter arterial coil embolization was performed. No subsequent progression of anemia or the deterioration of renal function was observed, showcasing the potential of ultra-low-dose contrast-enhanced PCD-CT for the detection of small vascular abnormalities while minimizing adverse effects on renal function.

Navigating nephrotoxic waters: A comprehensive overview of contrast-induced acute kidney injury prevention.

Contrast-induced acute kidney injury (CI-AKI) is the third leading cause of acute kidney injury deriving from the intravascular administration of contrast media in diagnostic and therapeutic procedures and leading to longer in-hospital stay and increased short and long-term mortality. Its pathophysiology, although not well-established, revolves around medullary hypoxia paired with the direct toxicity of the substance to the kidney. Critically ill patients, as well as those with pre-existing renal disease and cardiovascular comorbidities, are more susceptible to CI-AKI. Despite the continuous research in the field of CI-AKI prevention, clinical practice is based mostly on periprocedural hydration. In this review, all the investigated methods of prevention are presented, with an emphasis on the latest evidence regarding the potential of RenalGuard and contrast removal systems for CI-AKI prevention in high-risk individuals.

Effectiveness of edaravone in preventing contrast-induced nephropathy in high-risk patients undergoing coronary angiography: A randomized, double-blind trial.

Contrast-induced nephropathy (CIN) is a serious complication that occurs subsequent to the administration of contrast media for therapeutic angiographic interventions. As of present, no effective therapy exists to prevent its occurrence. This single-center double-blind randomized controlled trial aimed to evaluate the effect of edaravone, an antioxidant, in a group of high-risk patients undergoing coronary angiography. Ninety eligible patients with chronic kidney disease Stages 3-4 were randomly assigned to either the control group (n = 45) or the intervention group (n = 45). In the intervention group, one dosage of edaravone (60 mg) in 1 L of normal saline was infused via a peripheral vein 1 h prior to femoral artery-directed coronary angiography. Patients in the control group received an equal amount of infusion in their last hour before angiography. Both groups received intravenous hydration with 0.9% sodium 1 mL/kg/h starting 12 h before and continuing for 24 h after angiography. The primary outcome measure was the onset of CIN, defined as a 25% increase in serum creatinine levels 120 h after administration of contrast media. The occurrence of CIN was observed in 5.5% (n = 5) of the studied population: 2.2% of patients in the intervention group (n = 1) and 8.9% of controls (n = 4). However, this difference was not statistically significant. Administration of a single dosage of edaravone 1 h prior to infusion of contrast media led to a reduction in the incidence of CIN. Further investigations, employing larger sample sizes, are warranted to gain a comprehensive understanding of its efficacy.

Temperature-driven and discharge-driven variability of organic micropollutants in a large urban river and its implications for risk-based monitoring.

Urban rivers are exposed to an increasing load of organic micropollutants from wastewater effluent posing an ecological as well as public health hazard. One-off surveys can capture a snapshot of the pollution profile but fail to reveal the full scale of spatial and temporal heterogeneity. In the present study, 41 micropollutants (non-steroid anti-inflammatory drugs (NSAID), antihypertensives, antiepileptic, antidiabetic, antibiotics, iodinated contrast media (ICM), corrosion inhibitors, pesticides) were monitored every two weeks for one-year upstream and downstream of the Budapest metropolitan area in Danube River (336 samples total). ICMs, benzotriazoles and metamizole degradation products were detected in highest concentration regularly exceeding 100 ng/L. Median concentration of other pharmaceuticals ranged from <1 to 26 ng/L, while pesticides were typically below 10 ng/L. Variability of micropollutant concentration was primarily temporal, exhibiting two different patterns: (1) inverse correlation to river discharge, observed for corrosion inhibitors and carbamazepine (r= -0.505 to -0.665) or (2) inverse correlation to water temperature, observed primarily for ICMs, antihypertensives and antibiotics, r= -0.654 to -0.904). Temperature dependence was also significant after correcting for river discharge. Relative increase of pharmaceuticals was 2-134% after the metropolitan area, partially explained by emission estimates calculated from retail data and metabolization rates. The concentration of five ICMs (iopamidol in 100, iodixanol in 96, diatrizoate in 22, iomeprol in 21 and iohexol 13% of the samples) and two NSAIDs (ibuprofen and diclofenac (in 31.5 and 23% of the samples) exceeded the predicted no environmental effect concentration, posing a risk to algae (HQ=1.2-6) and fish (HQ=1.4-1.9), respectively. Results suggest that risk-based monitoring and risk management efforts should focus on ICMs, NSAIDs and industrial chemicals, taking into account that sampling in cold periods and during low flow provides the worst-case estimates.

Impact of SGLT2 Inhibitors on Renal Function in Type 2 Diabetic Patients with Coronary Artery Disease Undergoing Percutaneous Intervention: A Systematic Review and Meta-Analysis.

BACKGROUND AND OBJECTIVES: Contrast agents directly cause kidney toxicity in patients undergoing Percutaneous Intervention for cardiovascular disease with Type 2 diabetes. This meta-analysis aims to evaluate the effects of SGLT2-i on renal function in individuals undergoing Percutaneous Intervention. METHODS: The databases used for the search included PubMed, Scopus, Cochrane Central Registry of Controlled Trials, and Google Scholar. We considered Randomized controlled trials and observational studies published from January 2013 to August 2023. The eligibility to include the studies was assessed independently. The Cochrane modified data extraction form, and Joanna Briggs Institute was used. The Cochrane risk of bias tool and Newcastle-Ottawa quality assessment scale were used to assess the quality of the studies. The certainty of the evidence was assessed using GradePro software. RESULTS: The pooled estimate showed a substantial reduction in serum creatinine levels at 48- and 72-hours post-PCI who received SGLT2i (MD -9.57; 95% CI -18.36, -0.78; p-value 0.03) and (MD -14.40; 95% CI -28.57, -0.22; p-value 0.05). There was a decrease in the incidence of the CI-AKI among SGT2i users (RR: 0.46; 95% CI: 0.32, 0.67; p value< 0.0001). There was no significant difference in the number of patients requiring hemodialysis, but a smaller number of patients required hemodialysis among the SGLT2i users (RR: 0.88; 95% CI: 0.19, 4.07; p-value = 0.87). CONCLUSIONS: The use of SGLT2i confers substantial beneficial effects on kidney function and reduction of incidence of Contrast-induced acute kidney injury among patients undergoing PCI procedures for cardiovascular disease with diabetes.

Enhancing Preoperative Assessment of Endometrial Cancer: The Role of Diffusion-Weighted Magnetic Resonance Imaging in Evaluating Myometrial Invasion.

BACKGROUND: Endometrial cancer (EC) is the most common gynecological malignancy. Accurate preoperative staging is essential for guiding treatment. The depth of myometrial invasion is a key prognostic factor. This prospective study aimed to evaluate the added benefit of diffusion-weighted imaging (DWI) compared to T2-weighted imaging (T2WI) and dynamic contrast-enhanced MRI (DCE-MRI) for the preoperative assessment of myometrial invasion in EC. AIM AND OBJECTIVES: The aim of this prospective study was to evaluate the added benefit of DWI in the preoperative assessment of myometrial invasion in EC, in comparison with T2WI and DCE-MRI. The objectives were to assess the imaging characteristics of endometrial carcinoma on T2WI, DCE, and DW MR, to assess the depth of myometrial invasion and overall stage in EC patients, to compare the diagnostic performance of DCE-MRI with that of DW-MRI combined with T2WI, to describe how MR imaging findings can be combined with tumor histologic features and grading to guide treatment planning, and to evaluate the pitfalls and limitations of DCE and DW MR in the assessment of EC. MATERIALS AND METHODS: Thirty-one patients with histologically confirmed EC underwent preoperative pelvic MRI on a 1.5T scanner. T2WI, DWI (b-values 0, 1000 s/mm2), and DCE-MRI were performed. Two radiologists independently assessed myometrial invasion on T2WI, T2WI + DWI, and T2WI + DCE-MRI. Histopathology after hysterectomy was the reference standard. Diagnostic accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for each MRI protocol, with separate analyses for superficial (<50%) and deep (≥50%) myometrial invasions. RESULTS: The accuracy for assessing superficial invasion was 61.3% for T2WI, 87.1% for T2WI + DWI, and 87.1% for T2WI + DCE-MRI. For deep invasion, accuracy was 64.5% for T2WI, 90.3% for T2WI + DWI, and 90.3% for T2WI + DCE-MRI. Sensitivity, specificity, PPV, and NPV for T2WI + DWI and T2WI + DCE-MRI were high and comparable (88.9-91.7%) for both superficial and deep invasions. T2WI had markedly lower sensitivity and specificity. The differences between T2WI and the functional MRI protocols were statistically significant (p < 0.01). CONCLUSION: DWI and DCE-MRI significantly improve the diagnostic performance of MRI for the preoperative assessment of myometrial invasion depth in EC compared to T2WI alone. DWI + T2WI and DCE-MRI + T2WI demonstrate comparable high accuracy. DWI may be preferable since it is faster and avoids contrast administration.

More sustainable use of iodinated contrast media - Why?

OBJECTIVES: Based on a narrative review of the literature to 1) assess the need for and 2) report methods to help deliver a sustainable approach to iodinated contrast media (ICM) administration. KEY FINDINGS: Acute ICM shortages have been noted in the literature. As demand for contrast-enhanced imaging continues to increase and access to raw materials becomes more limited, such events may increase. Evidence from the literature has documented a range of iodinated contrast reduction strategies. These include individualised contrast-media dosing, multi-dose bulk ICM vials, switching to alternative modalities or the increased use of non-contrast examinations. The optimisation of imaging parameters, the use of saline chasers, and alternative contrast agents should be further considered. Given the rising concerns regarding the presence and effects of ICMs in waste and drinking water, further consideration of strategies for managing waste and excreted ICMs are starting to emerge. CONCLUSIONS: Sustainable ICM practices are needed to help avoid supply shortages and to help protect our environment. Such practices must be led and supported locally, nationally, and internationally. Sustainable ICM practices must be reflected within professional Standards of Proficiencies and be adopted by all members of the multidisciplinary team. IMPLICATIONS FOR PRACTICE: Changes to working practices surrounding the sustainable use of ICMs will likely become commonplace. New methods to ensure optimised ICM dosage with minimal wastage will be more heavily featured in departmental practices. Correct disposal of waste and excreted ICMs will also form part of future changes to practice.

Selective postmortem arterial angiography of head and neck using digital x-ray or computed tomography: A practical and rapid method to identify vascular injuries.

Identification of vascular injuries is crucial for complete postmortem evaluation and understanding of trauma deaths by the Medical Examiner. Some vascular injuries are difficult to evaluate due to challenging anatomic locations, especially in the head and neck. Documenting injuries of the facial and vertebral arteries is challenging and necessitates time-consuming dissections that can create artifacts and disfigurement. In busy medical examiner offices with a significant number of traumatic injuries, finding a creative solution to employ reliable postmortem angiography is desirable. At the Office of the Chief Medical Examiner for the State of Maryland (OCME), we created and effectively implemented a selective angiography procedure using traditional indwelling Foley catheters and water-soluble barium swallow contrast to evaluate arterial injuries using either digital radiography or computed tomography imaging modalities. This technique and imaging interpretation can be performed by a medical examiner or forensic pathology fellow after basic technical training and basic radiology training. This study outlines the technique, methods, and utilization of the procedure and describes the findings of six deaths due to vascular lesions from different injury mechanisms and disease processes and describes the ease of implementation on a broader scale in busy Medical Examiner's offices.

The environmental sustainability implications of contrast media supply chain disruptions during the COVID-19 pandemic: A document analysis of international practice guidelines.

INTRODUCTION: Travel restrictions implemented during the acute phases of the COVID-19 pandemic disrupted supply chain for critical radiology consumables including contrast media (CM) leading to shortages. Consequently, some departments had to restructure their clinical workflows in accordance to recommended guidelines to ensure safe continuity of patient care. This study aimed to summarise the temporary crisis-driven recommendations with implicit environmental sustainability essence and to analyse how these measures might inform the development of a more sustainable, long-term clinical guideline for safer and cost-effective CM usage without compromising diagnostic quality. METHODS: Documents were obtained through an electronic database search together with a relevant manual search in Google Scholar and relevant reference lists. The selected documents were subjected to a pre-defined eligibility criteria for inclusion. The READ approach was employed for document analysis and a thematic analysis of the obtained data was conducted. RESULTS: Of the 17 documents included, 70% (n = 12) emanate from the United States of America. The summary of the findings relate to minimising CM usage through strategic clinical approaches including optimisation of CM volumes, prioritisation of non-contrast imaging and/or alternative imaging depending on patient need without compromising diagnostic quality. CONCLUSION: Critical lessons of sustainability essence are implicitly embedded in the policy guidelines issued during the periods of acute CM shortage in the COVID-19 pandemic. These lessons were themed around CM conservation based on: type and priority of medical imaging investigation, kind of imaging modality and use of smaller vials over multi-dose vials packaging. IMPLICATIONS FOR PRACTICE: The temporary crisis-driven strategies may offer critical lessons for post-pandemic service delivery to enhance patient safety while saving cost and promoting greener practice via strategic clinical and operational monitoring of CM through policy renewal, education and training and collaboration with industry partners.

Risk of acute kidney injury following contrast-enhanced CT or MRI in a cohort of 3061 hospitalized children in China.

OBJECTIVES: To compare the risk of acute kidney injury (AKI) between hospitalized children who received intravenous contrast media for imaging examinations and those who did not. METHODS: This retrospective cohort study enrolled patients aged 0-18 years with serum creatinine levels before and after imaging examinations from 2015 to 2020 at Beijing Children's Hospital. Participants were classified into an exposure group or a control group. Log-binomial regression analysis was used to estimate the adjusted risk ratio (aRR) value for the association between exposure to contrast media and consequential AKI. After which, inverse probability treatment weighting was used to reduce systematic differences in baseline characteristics among the groups. Moreover, subgroup and sensitivity analyses were performed. Finally, multivariate logistic regression analysis was performed to identify risk factors for pediatric AKI. RESULTS: In total, 3061 pediatric patients were included in the analyses (median age, 4.5 [IQR, 1.3-8.9] years, 1760 males). According the KDIGO definition of AKI, the incidence of AKI in the exposure group, and the control group were 7.4% and 6.5%, respectively; furthermore, the aRR was 1.35 (95% CI: 1.31-1.39). In patients underwent CT, the risk of AKI in the exposure group of contrast media increased compared with the control group and the aRR was 1.39 (95% CI: 1.09-1.78). However, it is not observed in patients underwent MRI (aRR: 1.36; 95% CI: 0.96-1.95). According to our subgroup analysis of pediatric patients aged ≥ 2 years (aRR: 1.38; 95% CI: 1.05-1.82) and sensitivity analysis (aRR: 1.32, 95% CI: 1.08-1.61), the risk of AKI in the exposure group was greater than that in the control group. An increased risk to exposure to contrast media was seen in females (aRR: 1.41, 95% CI: 1.05-1.89) rather than males (aRR: 1.30, 95% CI: 0.99-1.70). According to the multivariate logistic regression analyses, the baseline eGFR (OR: 1.02; 95% CI: 1.01-1.03) and comorbidities (OR: 2.97; 95% CI: 1.89-4.65) were risk factors, while age (OR: 0.87; 95% CI: 0.84-0.91) was a protective factor against AKI. CONCLUSION: The evidence from the present study suggested that the increased risk of AKI in hospitalized children induced by intravascular contrast should not be ignored.

Pictorial review of multiparametric MRI in bladder urothelial carcinoma with variant histology: pearls and pitfalls.

Bladder cancer (BC), predominantly comprising urothelial carcinomas (UCs), ranks as the tenth most common cancer worldwide. UCs with variant histology (variant UC), including squamous differentiation, glandular differentiation, plasmacytoid variant, micropapillary variant, sarcomatoid variant, and nested variant, accounting for 5-10% of cases, exhibit more aggressive and advanced tumor characteristics compared to pure UC. The Vesical Imaging-Reporting and Data System (VI-RADS), established in 2018, provides guidelines for the preoperative evaluation of muscle-invasive bladder cancer (MIBC) using multiparametric magnetic resonance imaging (mpMRI). This technique integrates T2-weighted imaging (T2WI), dynamic contrast-enhanced (DCE)-MRI, and diffusion-weighted imaging (DWI) to distinguish MIBC from non-muscle-invasive bladder cancer (NMIBC). VI-RADS has demonstrated high diagnostic performance in differentiating these two categories for pure UC. However, its accuracy in detecting muscle invasion in variant UCs is currently under investigation. These variant UCs are associated with a higher likelihood of disease recurrence and require precise preoperative assessment and immediate surgical intervention. This review highlights the potential value of mpMRI for different variant UCs and explores the clinical implications and prospects of VI-RADS in managing these patients, emphasizing the need for careful interpretation of mpMRI examinations including DCE-MRI, particularly given the heterogeneity and aggressive nature of variant UCs. Additionally, the review addresses the fundamental MRI reading procedures, discusses potential causes of diagnostic errors, and considers future directions in the use of artificial intelligence and radiomics to further optimize the bladder MRI protocol.

Management of acute coronary syndromes requiring coronary angiography in patients with drug reaction with eosinophilia and systemic symptoms syndrome induced by iodinated contrast media: two case reports and narrative review.

Background: Hypersensitivity reactions to iodinated contrast media (ICM) are frequently encountered in clinical practice. Severe manifestations, despite being infrequent, can be life-threatening and represent an issue when re-administration of ICM is required. Clear recommendations on prevention and management of relapses are still lacking. Case summary: We present the cases of two patients presenting with acute coronary syndrome requiring urgent coronary angiography, with an anamnesis of ICM-induced drug reaction with eosinophilia and systemic symptoms syndrome. Both patients safely underwent a coronary angiography with the use of a different ICM (iobitridol) to the one linked to hypersensitivity manifestations, after premedication with corticosteroids and H1 antagonists. Discussion: Our experience highlights that in clinical situations in which the use of ICM is urgently needed, premedication with corticosteroids and H1 antagonists together with the choice of an alternative contrast agent (when the culprit is known) represents an effective strategy to perform a potentially life-saving procedure while avoiding serious systemic allergic reactions.

Temporal evolution of primary angiitis of the central nervous system (PACNS) on MRI following immunosuppressant treatment.

PURPOSE: To systematically analyse the time course of vessel wall enhancement and associated stenosis in patients with primary angiitis of the central nervous system (PACNS) following immunosuppressive therapy. MATERIAL AND METHODS: Two neuroradiologists retrospectively analysed MRIs of patients with PACNS seen at the Bern University Hospital and the St. Gallen Cantonal Hospital between 2015 and 2020. MRIs were examined for the presence of vessel wall enhancement, length of vessel wall enhancement (mm), circumferential extent of enhancement (degree) and degree of stenosis (%). Descriptive statistics and measurements of interobserver reliability were obtained. To investigate the temporal profiles of the variables following the commencement of immunosuppressant treatment, four series of Bayesian generalised multi-level models were generated. RESULTS: A total of 23 patients with 43 affected vessels identified from 209 MRI exams were evaluated (mean follow-up: 715 days, standard deviation ± 487 days), leading to a complete dataset of 402 entries. Vessel wall enhancement and circumferential extent of enhancement decreased for approximately 1 year after the initiation of immunosuppressant therapy. Changes were more pronounced in younger patients. Disappearance of vessel wall enhancement (in at least one vessel) was seen in about half of patients after a median of 172 days interquartile range 113-244, minimum 54 days, maximum 627 days. CONCLUSIONS: This study evaluated the typical time course of vessel wall enhancement in patients with PACNS. Our results could be a useful reference for radiologists and clinicians interpreting follow-up imaging in patients with PACNS. CRITICAL RELEVANCE STATEMENT: Routine clinical exams can be interpreted with more confidence when radiologists are aware of the typical temporal evolution of vessel wall enhancement in patients with primary angiitis of the central nervous system after initiation of immunosuppressive therapy. KEY POINTS: Few data exist for vessel wall imaging of primary angiitis of the central nervous system. Following immunosuppressant therapy, vessel wall enhancement decreases for approximately one year. These results may serve as a reference for radiologists performing follow-up imaging.

Contrast Reactions and Approaches to Staffing the Contrast Reaction Management Team.

RATIONALE AND OBJECTIVES: Managing contrast reactions is critical as contrast reactions can be life-threatening and unpredictable. Institutions need an effective system to handle these events. Currently, there is no standard practice for assigning trainees, radiologists, non-radiologist physicians, or other non-physician providers for management of contrast reaction. MATERIALS AND METHODS: The Association of Academic Radiologists (AAR) created a task force to address this gap. The AAR task force reviewed existing practices, studied available literature, and consulted experts related to contrast reaction management. The Society of Chairs of Academic Radiology Departments (SCARD) members were surveyed using a questionnaire focused on staffing strategies for contrast reaction management. RESULTS: The task force found disparities in contrast reactions management across institutions and healthcare providers. There is a lack of standardized protocols for assigning personnel for contrast reaction management. CONCLUSION: The AAR task force suggests developing standardized protocols for contrast reaction management. The protocols should outline clear roles for different healthcare providers involved in these events.

Virtual noncontrast images reveal gouty tophi in contrast-enhanced dual-energy CT: a phantom study.

BACKGROUND: Dual-energy computed tomography (DECT) is useful for detecting gouty tophi. While iodinated contrast media (ICM) might enhance the detection of monosodium urate crystals (MSU), higher iodine concentrations hamper their detection. Calculating virtual noncontrast (VNC) images might improve the detection of enhancing tophi. The aim of this study was to evaluate MSU detection with VNC images from DECT acquisitions in phantoms, compared against the results with standard DECT reconstructions. METHODS: A grid-like and a biophantom with 25 suspensions containing different concentrations of ICM (0 to 2%) and MSU (0 to 50%) were scanned with sequential single-source DECT using an ascending order of tube current time product at 80 kVp (16.5-220 mAs) and 135 kVp (2.75-19.25 mAs). VNC images were equivalently reconstructed at 80 and 135 kVp. Two-material decomposition analysis for MSU detection was applied for the VNC and conventional CT images. MSU detection and attenuation values were compared in both modalities. RESULTS: For 0, 0.25, 0.5, 1, and 2% ICM, the average detection indices (DIs) for all MSU concentrations (35-50%) with VNC postprocessing were respectively 25.2, 36.6, 30.9, 38.9, and 45.8% for the grid phantom scans and 11.7, 9.4, 5.5, 24.0, and 25.0% for the porcine phantom scans. In the conventional CT image group, the average DIs were respectively 35.4, 54.3, 45.4, 1.0, and 0.0% for the grid phantom and 19.4, 17.9, 3.0, 0.0, and 0.0% for the porcine phantom scans. CONCLUSIONS: VNC effectively reduces the suppression of information caused by high concentrations of ICM, thereby improving the detection of MSU. RELEVANCE STATEMENT: Contrast-enhanced DECT alone may suffice for diagnosing gout without a native acquisition. KEY POINTS: • Highly concentrated contrast media hinders monosodium urate crystal detection in CT imaging • Virtual noncontrast imaging redetects monosodium urate crystals in high-iodinated contrast media concentrations. • Contrast-enhanced DECT alone may suffice for diagnosing gout without a native acquisition.

Disease severity prognostication in primary sclerosing cholangitis: a validation of the Anali scores and comparison with the potential functional stricture.

OBJECTIVES: Our aim was twofold. First, to validate Anali scores with and without gadolinium (ANALIGd and ANALINoGd) in primary sclerosing cholangitis (PSC) patients. Second, to compare the ANALIs prognostic ability with the recently-proposed potential functional stricture (PFS). MATERIALS AND METHODS: This retrospective study included 123 patients with a mean age of 41.5 years, who underwent gadoxetic acid-enahnced MRI (GA-MRI). Five readers independently evaluated all images for calculation of ANALIGd and ANALINoGd scores based upon following criteria: intrahepatic bile duct change severity, hepatic dysmorphia, liver parenchymal heterogeneity, and portal hypertension. In addition, hepatobiliary contrast excretion into first-order bile ducts was evaluated on 20-minute hepatobiliary-phase (HBP) images to assess PFS. Inter- and intrareader agreement were calculated (Fleiss´and Cohen kappas). Kaplan-Meier curves were generated for survival analysis. ANALINoGd, ANALIGd, and PFS were correlated with clinical scores, labs and outcomes (Cox regression analysis). RESULTS: Inter-reader agreement was almost perfect (Ï° = 0.81) for PFS, but only moderate-(Ï° = 0.55) for binary ANALINoGd. For binary ANALIGd, the agreement was slightly better on HBP (Ï° = 0.64) than on arterial-phase (AP) (Ï° = 0.53). Univariate Cox regression showed that outcomes for decompensated cirrhosis, orthotopic liver transplantation or death significantly correlated with PFS (HR (hazard ratio) = 3.15, p < 0.001), ANALINoGd (HR = 6.42, p < 0.001), ANALIGdHBP (HR = 3.66, p < 0.001) and ANALIGdAP (HR = 3.79, p < 0.001). Multivariate analysis identified the PFS, all three ANALI scores, and Revised Mayo Risk Score as independent risk factors for outcomes (HR 3.12, p < 0.001; 6.12, p < 0.001; 3.56, p < 0.001;3.59, p < 0.001; and 4.13, p < 0.001, respectively). CONCLUSION: ANALINoGd and GA-MRI-derived ANALI scores and PFS could noninvasively predict outcomes in PSC patients. CLINICAL RELEVANCE STATEMENT: The combined use of Anali scores and the potential functional stricture (PFS), both derived from unenhanced-, and gadoxetic acid enhanced-MRI, could be applied as a diagnostic and prognostic imaging surrogate for counselling and monitoring primary sclerosing cholangitis patients. KEY POINTS: Primary sclerosing cholangitis patients require radiological monitoring to assess disease stability and for the presence and type of complications. A contrast-enhanced MRI algorithm based on potential functional stricture and ANALI scores risk-stratified these patients. Unenhanced ANALI score had a high negative predictive value, indicating some primary sclerosing cholangitis patients can undergo non-contrast MRI surveillance.

Reduced contrast dose for CT head studies during COVID-19-related contrast shortage: Lesson from a crisis.

OBJECTIVE: Intravenous contrast injection protocol for certain CT studies at our institution was revised in June 2022 in response to the global shortage of iohexol. This included CT head studies performed for neuro-navigation (contrast dose from 90 mL to 70 mL). The quality of these studies was assessed. METHODS: Consecutive CT scans before (n = 32) and after (n = 32) contrast dose reduction were reviewed. Demographic data was obtained from the chart. Subjective observations made by two radiologists in consensus included overall study quality (Likert scale of 1 to 5) and lesion location, margins and internal characteristics that were compared with MRI findings (reference standard) using Fisher's exact test. Superior sagittal sinus attenuation, used as an objective measurement of enhancement, and lesion size were compared using Student's t-test. The institutional database was searched for any study requiring repetition or deemed non-diagnostic. RESULTS/DISCUSSION: The average age (61.1 ± 12.7 years and 61.6 ± 14.9 years) and body surface area (BSA) (1.9 ± 0.3 m2 and 1.9 ± 0.02 m2) was not significantly different (p > 0.05) between groups. There was no significant difference (p > 0.05) in objective or subjective enhancement between the two groups. There was no significant difference between CT and MRI for lesion size, location, number, margins and internal enhancement characteristics in the two groups. No study required repetition or was reported as non-diagnostic. There was no adverse comment about study quality in operative notes. CONCLUSION: Reduced contrast dose neuro-navigation CT head studies are not different in quality compared to the conventional studies.

Diagnostic Efficacy and Safety of Low-Contrast-Dose Dual-Energy CT in Patients With Renal Impairment Undergoing Transcatheter Aortic Valve Replacement.

OBJECTIVE: This study aimed to evaluate the diagnostic efficacy and safety of low-contrast-dose, dual-source dual-energy CT before transcatheter aortic valve replacement (TAVR) in patients with compromised renal function. MATERIALS AND METHODS: A total of 54 consecutive patients (female:male, 26:38; 81.9 ± 7.3 years) with reduced renal function underwent pre-TAVR dual-energy CT with a 30-mL contrast agent between June 2022 and March 2023. Monochromatic (40- and 50-keV) and conventional (120-kVp) images were reconstructed and analyzed. The subjective quality score, vascular attenuation, contrast-to-noise ratio (CNR), and signal-to-noise ratio (SNR) were compared among the imaging techniques using the Friedman test and post-hoc analysis. Interobserver reliability for aortic annular measurement was assessed using the intraclass correlation coefficient (ICC) and Bland-Altman analysis. The procedural outcomes and incidence of post-contrast acute kidney injury (AKI) were assessed. RESULTS: Monochromatic images achieved diagnostic quality in all patients. The 50-keV images achieved superior vascular attenuation and CNR (P < 0.001 in all) while maintaining a similar SNR compared to conventional CT. For aortic annular measurement, the 50-keV images showed higher interobserver reliability compared to conventional CT: ICC, 0.98 vs. 0.90 for area and 0.97 vs. 0.95 for perimeter; 95% limits of agreement width, 0.63 cm² vs. 0.92 cm² for area and 5.78 mm vs. 8.50 mm for perimeter. The size of the implanted device matched CT-measured values in all patients, achieving a procedural success rate of 92.6%. No patient experienced a serum creatinine increase of ≥ 1.5 times baseline in the 48-72 hours following CT. However, one patient had a procedural delay due to gradual renal function deterioration. CONCLUSION: Low-contrast-dose imaging with 50-keV reconstruction enables precise pre-TAVR evaluation with improved image quality and minimal risk of post-contrast AKI. This approach may be an effective and safe option for pre-TAVR evaluation in patients with compromised renal function.