Nonionic Contrast Research Articles

Morphological evaluation for the narrowest section of the patent ductus arteriosus in infants by CT: a crucial point for device closure.

The minimum diameter of the patent ductus arteriosus measured in the lateral angiographic view is usually used to determine the device size. Sometimes the device can be easily removed from the patent ductus arteriosus, even if it appears to be the optimum size. From 2016 to 2021, 29 patients who underwent contrast-enhanced CT prior to patent ductus arteriosus closure included. Morphological evaluation of the narrowest part of the patent ductus arteriosus was performed on contrast-enhanced CT. We also examined whether there were differences in morphology depended on Krichenko classification, age, and the diameter of the narrowest portion of the patent ductus arteriosus. At the time of treatment, the median age was 4.8 (range, 1-52) months, and the median weight was 5.0 (2.5-12.7) kg. The median minimum vertical diameter of patent ductus arteriosus was 2.9 (1.6-6.6) mm. The narrowest patent ductus arteriosus part in the contrast CT imaging showed horizontal-to-vertical diameter ratios in the range of 1.0-1.7, with no case where the vertical diameter was larger than the horizontal diameter. The median horizontal-to-vertical diameter ratio by Krichenko type was: A, 1.22; C, 1.29; E, 1.62(p = 0.017). When classifying the patients into a group aged under six months (n = 21) and a group aged six months or older (n = 8), the respective median horizontal-to-vertical diameter ratio was 1.34 and 1.15 (p = 0.027). The vertical patent ductus arteriosus diameter was not correlated with the elliptical shape. Most patent ductus arteriosus cases have a horizontally oriented elliptical shape in this study. This characteristic showed high reproducibility and is important information that angiography cannot evaluate.

PEGylated Pemetrexed and PolyNIPAM Decorated Gold Nanoparticles: A Biocompatible and Highly Stable CT Contrast Agent for Cancer Imaging.

This study describes a multifunctional nanoparticle platform for targeted CT imaging and therapy of cancers. Pemetrexed (conjugated with polyethylene glycol, MW 2000 Da) and polyNIPAM (PEGylated) were designed for targeted delivery to folate receptors and thermally ablated tumors, respectively. These moieties were coated on gold nanoparticles (7 and 30 nm), and the prepared compounds were characterized using 1H NMR, FT-IR, CHNS, DLS, TEM, TGA, and UV-vis. The resulting agents exhibited 2-4 times higher X-ray attenuation compared to Visipaque and demonstrated specific accumulation in tumor tissue (4T1 xenograft model) 90 min after injection in mice. The nanoparticles displayed anticancer activity against 4T1 and MDA-MB-231 breast cancer cells (IC50: 182.87 and 206.18 μg/mL) and good biocompatibility. Importantly, the platform showed excellent stability over a year and at pH 2-12 and temperature range of -78 to 40 °C, and a water-dichloromethane extraction method was optimized for efficient purification, facilitating large-scale production.

Zero-Contrast Transcatheter Aortic Valve Implantation vs. Standard Practice: Periprocedural and Long-Term Clinical Outcomes.

Background: We aimed to compare the procedural efficacy and long-term clinical results of a totally contrast-free Transcatheter Aortic Valve Implantation (TAVI) procedure (i.e., contrast dye was not used for either the pre-procedural assessment or during the procedure) to those of standard practice in patients with severe renal dysfunction. Methods: All consecutive patients with a glomerular filtration rate (GFR) ≤ 35 mL/min and severe aortic stenosis who were treated with transfemoral TAVI at our Institution were included in the registry. The zero-contrast patients underwent carbon dioxide angiography and a non-contrast CT scan for assessment of vascular access suitability, and aortic annulus sizing was performed by a TEE, and the procedural guidance was fluoroscopic and echocardiographic. Procedural outcomes were evaluated, and clinical long-term follow-up was performed for all included patients. Results: A total of 44 patients (median age, 85 (IQR, 80.75-87.00)) were included in the zero-contrast group (TEE guidance and general anesthesia in 37 (84%) patients), while 63 patients were included in the standard practice arm (82 ± 78 mL of contrast dye used). Procedural success was obtained in 100% of cases. There were no differences in procedural outcomes, including final mean aortic gradients (5.5 (IQR, 5.0-10.0) mmHg in the zero-contrast group vs. 6.0 (IQR, 5.0-10.0) mmHg in the standard practice group) and rate of at least a moderate paravalvular leak (0% vs. 1.6% in the zero-contrast and standard practice groups, respectively; p = 0.31). No differences in AKI during the hospital stay were observed. Over a median follow-up of 3.3 years, there was a significantly lower rate of AKI (1.2% vs. 25.9%, p < 0.001) and rehospitalizations (1.6% vs. 35.5%, p < 0.00) in standard practice group. Conclusions: We showed for the first time the feasibility and efficacy of a totally contrast-free strategy compared to standard practice in TAVI patients with severe renal dysfunction. Besides achieving comparable procedural results, the zero-contrast strategy showed a better long-term clinical outcome in reducing hospital readmissions for kidney function deterioration.

Retrospective study of detecting oesophageal injuries post neck trauma: CTA versus fluoroscopy.

Timely detection of oesophageal injuries post-penetrating neck trauma is imperative because of the associated high morbidity and mortality. Patients commonly undergo both CT angiography (CTA) and contrast swallow studies (fluoroscopic oesophagography) when oesophageal injury is suspected. To determine the radiological findings of oesophageal injury after penetrating neck trauma comparing CTA and fluoroscopic oesophagography at a single tertiary centre. The study retrospectively reviewed the data from CTA and fluoroscopic oesophagography reports of patients suspected of oesophageal injuries secondary to penetrating neck trauma at a tertiary hospital in South Africa from January 2018 to December 2022. A total of 76 records were reviewed. The mean age for the participants was 31.5 years, ranging from 0.75-66 years. In this study 6/76 (8%) patients had confirmed oesophageal injury on fluoroscopy, which is considered the gold standard. The majority of penetrating neck injuries were in the 20-29 year age group, with 33/76 (43%) injuries. Stab wounds as the mechanism of injury accounted for 57/76 (75%). Dysphagia was experienced by 10/76 (13%) of those who had injuries. Zone I injuries accounted for 33/76 (43%) of the injuries. The incidence of oesophageal injuries secondary to penetrating neck injuries is comparable to previous studies. This study determined that CTA has a high sensitivity but low specificity. Fluoroscopic oesophagography should, therefore, be performed in patients who have an abnormal CTA coupled with clinical signs and symptoms of oesophageal injury.

EP554 - Sigmoid Diverticular Perforation Mimicking Boerhaave Syndrome – A Case Report

Abstract Introduction Subcutaneous emphysema is a rare presenting complaint and can represent severe underlying pathology. Atypical occurrences of abdominal emphysema in diverticular perforations have been reported but emphysema within the thorax and neck due to sigmoid perforation is rare. We present an elderly male patient who presented with neck surgical emphysema secondary to diverticular perforation. Case presentation A 78-year-old man presented with two days history of shortness of breath and two weeks history of abdominal pain worse on coughing, newly hoarse voice, one episode of vomiting and fever. His past medical history included palliative malignant melanoma, ischaemic heart disease, asthma and chronic kidney disease. At presentation, he was tachycardic and had 95% oxygen saturation. Physical examination revealed extensive upper body subcutaneous emphysema and tender lower abdomen. Admission blood tests showed white cell count of 9.8 x 109 and C-reactive protein of 148mg/L. Urgent contrast CT scan with oral contrast excluded oesophageal perforation but demonstrated perforated sigmoid diverticulum. Due to the patient’s extensive co-morbidities and limited intra-abdominal contamination, he was managed conservatively. Discussion The patient initially had CT chest with IV contrast followed by CT with oral contrast, encompassing the abdomen and pelvis, leading to the accurate diagnosis. The presumed path of gas tracking from the perforation through the diaphragmatic hiatus contributed to the delay in reaching the correct diagnosis. In cases where patients present with subcutaneous emphysema in the upper body, particularly when CT thorax with oral contrast has ruled out oesophageal perforation, clinical suspicion for intra-abdominal causes should persist. Despite the presence of significant surgical emphysema, this patient demonstrated a favourable response to conservative measures.

TUMOR IN HORSESHOE KIDNEYS: A CASE REPORT AND LITERATURE REVIEW

Objective: This study aims to report a renal tumor in a horseshoe kidney successfully treated with an open left nephrectomy. Case(s) Presentation: A 3 years old girl with a lump in the left abdomen and intermittent hematuria was referred to our hospital. Whole abdominal contrast CT scan showed the presence of a left renal mass in a horseshoe kidney that infiltrates the left renal artery and is attached to the spleen. The patient underwent preoperative chemotherapy followed by surgical resection. Discussion: In a horseshoe kidney, renal tumors are uncommon. The limited kidney mobilization and access to the renal hilum and the abnormal and highly variable vasculature make surgical treatment of a tumor in a horseshoe kidney extremely difficult. Conclusion: Open surgery continues to be the treatment of choice for horseshoe kidney tumors due to their anatomical complexity, particularly in cases where the tumor is difficult to eradicate. Keywords: Renal tumor, horseshoe kidney, surgical management.

Machine Learning Platform for Disease Diagnosis with Contrast CT Scans

Machine learning has gained significant recognition as a powerful approach for medical diagnosis using medical images. Among various medical imaging modalities, contrast-enhanced CT (CECT) is utilized to obtain additional diagnostic information that improves visualization and evaluation of certain abnormalities in the human body, as well as to observe temporal changes in lesions and tumors across different time phases. However, developing such medical diagnostic systems presents two significant challenges: high technical complexity and substantial development effort. This paper presents a software platform that effectively addresses these challenges. Specifically, we propose a unified software process that fully automates contrast-enhanced CT (CECT)-specific disease diagnosis, with key tasks performed by leveraging task-specific machine learning models to enhance accuracy. The platform incorporates a suite of specialized machine learning models into the diagnostic process, enabling precise diagnosis of lesions, malignancies, tumors, tumor characteristics, and temporal changes over phases. Moreover, the platform has been designed according to the Open–Closed Principle, allowing it to be applicable to a wide range of CECT-based diagnostic systems. The platform has been implemented in Python using the Scikit-learn and TensorFlow libraries. To validate its applicability and reusability, a hepatocellular carcinoma (HCC) diagnosis system has been implemented.

Role of Virtual Monoenergetic Images in the Assessment of Vessel Enhancement in Segmental Level in Third-Generation Dual-Source Dual-Energy CT Pulmonary Angiography—A Prospective Study

Abstract Introduction Pulmonary embolism is the third most common cause of cardiovascular death worldwide and imaging plays a pivotal role in establishing the diagnosis. Computed tomography pulmonary angiography (CTPA) scores over other modalities and is the current diagnostic investigation of choice. In this study, we assessed the main pulmonary artery and its corresponding segmental artery attenuation in reconstructed virtual monoenergetic (mono plus) images (VMI-MP) and linear blended images (spectral post processing, SPP) obtained from dual-energy CTPA. The values were compared using contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR). Materials and Methods Forty patients (mean age group, 53.6 years; 26 females and 14 males) with segmental pulmonary thromboembolism were included in this prospective study. The patients underwent CTPA study using bolus tracking in the dual-source CT-SOMATOM Force, Siemens. Postcontrast datasets (90 kV, 150 kV, and SPP) were used to reconstruct the monoenergetic images using syngo.via software virtually. Comparison was done between bivariate samples using the paired sample t-test. Results The mean Hounsfield unit (HU) artery in the left lung for VMI-MP and SPP images were 886.9 ± 242 and 356.8 ± 121.3 HU, respectively. Similarly, for the right lung, it was 868.3 ± 243.5 and 336.1 ± 105.5 HU, respectively. The mean attenuation of the arteries in MP images was higher and statistically significant (p-value &lt;0.005). Likewise, the CNR) and SNR were found to have a statistically significant p-value (&lt;0.005). An acceptable increase in image noise was seen in VMI as compared with SPP images. Conclusion Low-keV VMIs perform more effectively than the conventional polyenergetic spectrum to evaluate vessel attenuation, which in turn increases thrombus detectability. The increased CNR in VMI enables improved lesion conspicuity.

DFT/TDDFT Investigation of the Effect of Electron Acceptor Groups on Photovoltaic Performance Using Phenothiazine‐Based D‐Ai‐π‐A Dyes for DSSC Applications

AbstractThis review focuses mostly on organic dye‐sensitized solar cells, as they are an attractive, environmentally friendly alternative to traditional silicon solar cells for the production of renewable energy at a lower cost. The dye chromophore is recognized as the central component of the DSSC device. To improve the electrochemical, photovoltaic, and absorption properties of organic sensitizing dyes, we have designed a series of eight new dyes Pi (i = 1.8) based on the DPA‐2 architecture (the reference molecule). We have investigated the effects of internal absorption of different acceptor groups in D‐Ai‐π‐A before and after binding to the TiO2 cluster surface on the ability to inject electrons into the surface. The benzophenothiazine is the D donor, the π‐spacer is furan, and the A acceptor is cycnoacrylic acid. We are using time‐dependent density functional theory (TD‐DFT), and density functional theory (DFT) in our quantum calculations. It is theoretically possible to predict suitable candidates for the DSSC device and identify correlations between their structure and properties by using DFT and TD‐DFT simulations to thoroughly study in detail electronic structures, natural binding orbital (NBO), analysis of UV‐visible absorption spectra, parameters influencing short‐circuit current density (JSC), open‐circuit voltage (VOC), and intramolecular charge transfer (ICT). Additionally, the relationship between optoelectronic properties and molecular structure was investigated, and the effect of auxiliary acceptor groups (Ai) on the primary photovoltaic properties of the reference molecule DPA‐2. The results show that by changing the internal acceptor to DPA‐2 could create a more coplanar and rigid structure. This would cause the energy gap (Eg) for each of the dyes created to significantly shrink, reducing it from 2.29 to 1.38 eV. The absorption spectra's λmax for each dye would also change color, this was because the acceptor moiety Ai of the phenothiazine moiety changed when it came to DPA‐2 (not including compounds P1 and P4). In contrast, P6 and P7 dyes demonstrate an absorption range beyond 500 nm, implying a more efficient utilization of sunlight in the visible spectrum compared to other dyes. Furthermore, all organic dyes show a robust LHE performance (0.919 to 0.993), correlating with the lowest ΔGreg values (0.097 to 0.356) and the most negative ΔGinject values (−2.067 to −1.121). The power conversion efficiency of PCE and JSC could increase according to these results. Therefore, theoretical research into adding a second internal acceptor group to the D‐Ai‐π‐A structure should produce new methods for improving solar energy output.

Gold Nanoparticle Transport in the Injured Kidneys with Elevated Renal Function Biomarkers.

Renal function biomarkers such as serum blood urea nitrogen (BUN) and creatinine (Cr) serve as key indicators for guiding clinical decisions before administering kidney-excreted small-molecule agents. With engineered nanoparticles increasingly designed to be renally clearable to expedite their clinical translation, understanding the relationship between renal function biomarkers and nanoparticle transport in diseased kidneys becomes crucial to their biosafety in future clinical applications. In this study, renal-clearable gold nanoparticles (AuNPs) are used as X-ray contrast agents to noninvasively track their transport and retention in cisplatin-injured kidneys with varying BUN and Cr levels. The findings reveal that AuNP transport is significantly slowed in the medulla of severely injured kidneys, with BUN and Cr levels elevated to 10 times normal. In mildly injured kidneys, where BUN and Cr levels only four to five times higher than normal, AuNP transport and retention are not predictable by BUN and Cr levels but correlate strongly with the degree of tubular injury due to the formation of gold-protein casts in the Henle's loop of the medulla. These results underscore the need for caution when employing renal-clearable nanomedicines in compromised kidneys and highlight the potential of renal-clearable AuNPs as X-ray probes forassessing kidney injuries noninvasively.

P001 AN UNCOMMON CAUSE OF HIGH BLOOD PRESSURE IN YOUNG BASKETBALL PLAYER

Paragangliomas are rare neuroendocrine tumors that affect approximately 1.5–9 patients per million. They originate from chromaffin cells of the adrenal medulla or sympathetic and parasympathetic ganglia. Paragangliomas account for 10%–20% of retroperitoneal tumors and can manifest at any age. These tumors can secrete catecholamines, leading to symptoms such as hypertension, headaches, and diaphoresis.However, palpitations or tachycardia may also be present. Definitive treatment entails surgical resection, with acceptable rates of morbidity and mortality, necessitating careful patient preparation and intraoperative management. Case Presentation: We present the case of a 29-year-old man with a BMI 26,5 kg/m2, who is physically active and without other cardiovascular risk factors, episodic hypertension, headaches and blush. A contrast CT scan of the abdomen revealed a retroperitoneal intercavoaortic mass and 24-hour urine Normetanephrines were significantly elevated, indicating a functional paraganglioma. Laboratory tests revealed an elevated plasma normetanephrine level of 1838 pg/ml (reference values 0 - 180 pg/ml). The patient was prepared for surgery with alpha blockers, followed by beta blockers. Intraoperative blood pressure elevation was managed with intravenous beta blockers. Postoperatively, the patient did not require anti-hypertensives. The tumor, measuring 6x4x3.5 cm, histopathology and immunohistochemistry confirmed the diagnosis of a normetanephrine producing paraganglioma. The genetic study revealed a pathogenic variant in the SDHB gene, specifically the c.166_170delCCTCA (p.Pro56Tyrfs*5) in heterozygosity. This variant is associated with a 49% risk of Pheochromocytoma and Hereditary Paraganglioma, a 14% risk of Renal Carcinoma and susceptibility to Gastrointestinal Stromal Tumors. The c.166_170delCCTCA variant follows an autosomal dominant inheritance pattern, indicating a 50% risk of recurrence. Conclusions: The diagnosis of extra-adrenal retroperitoneal paragangliomas remains challenging due to the silent evolution of the condition. It is essential to consider screening patients who are young, and present with resistant arterial hypertension for secondary hypertension.

Adjustment of scan delay for bolus tracking with cardiothoracic ratio of CT scout image for hepatic artery phase of hepatic dynamic CT.

This study aimed to determine the scan delay for bolus tracking in the hepatic artery phase (HAP) of hepatic dynamic computed tomography (CT) using the cardiothoracic ratio (CTR) from CT scout images. We retrospectively studied 188 patients who underwent hepatic dynamic CT, 24 of whom had scan delays adjusted for CTR. The contrast enhancement of the abdominal aorta, portal vein, hepatic vein, and hepatic parenchyma was calculated for HAP. The adequacy of the scan timing for HAP was assessed using three classifications: early, appropriate, or late. The effect of HAP on scan timing adequacy was determined using multivariate logistic regression analysis, and the optimal cutoff value of CTR was evaluated using receiver operating characteristic analysis. The trigger times for bolus tracking (odds ratio: 1.58) and CTR (odds ratio: 1.23) were significantly affected by the appropriate scan timing of the HAP. The optimal cutoff value of CTR was 59.3%. The scan timing of HAP with a scan delay of 15s was 14% of early and 86% of appropriate, and the proportion of early in CTR ≥ 60% (early, 52%; appropriate, 48%) was higher than that in CTR < 60% (early, 6%; appropriate, 94%). Adjusting the scan delay to 20s in CTR ≥ 60% increased the proportion of appropriate (early, 4%; appropriate, 96%). The CTR of a CT scout image is an effective index for determining the scan delay for bolus tracking. Adjusting the scan delay by CTR can provide appropriate HAP images in more patients. Trial registration number: R-080; date of registration: 9 March 2023, retrospectively registered.

Assessment of Hepato-Renal Functions and Markers of Oxidative Stress in Animals Exposed to Ionic Contrast Media

Assessment of Hepato-Renal Functions and Markers of Oxidative Stress in Animals Exposed to Ionic Contrast Media

Survey of CT radiation doses and iodinated contrast medium administration: an international multicentric study.

To assess the relationship between intravenous iodinated contrast media (ICM) administration usage and radiation doses for contrast-enhanced (CE) CT of head, chest, and abdomen-pelvis (AP) in international, multicenter settings. Our international (n = 16 countries), multicenter (n = 43 sites), and cross-sectional (ConRad) study had two parts. Part 1: Redcap survey with questions on information related to CT and ICM manufacturer/brand and respective protocols. Part 2: Information on 3,258 patients (18-96 years; M:F 1654:1604) who underwent CECT for a routine head (n = 456), chest (n = 528), AP (n = 599), head CT angiography (n = 539), pulmonary embolism (n = 599), and liver CT examinations (n = 537) at 43 sites across five continents. The following information was recorded: hospital name, patient age, gender, body mass index [BMI], clinical indications, scan parameters (number of scan phases, kV), IV-contrast information (concentration, volume, flow rate, and delay), and dose indices (CTDIvol and DLP). Most routine chest (58.4%) and AP (68.7%) CECT exams were performed with 2-4 scan phases with fixed scan delay (chest 71.4%; AP 79.8%, liver CECT 50.7%) following ICM administration. Most sites did not change kV across different patients and scan phases; most CECT protocols were performed at 120-140 kV (83%, 1979/2685). There were no significant differences between radiation doses for non-contrast (CTDIvol 24 [16-30] mGy; DLP 633 [414-702] mGy·cm) and post-contrast phases (22 [19-27] mGy; 648 [392-694] mGy·cm) (p = 0.142). Sites that used bolus tracking for chest and AP CECT had lower CTDIvol than sites with fixed scan delays (p < 0.001). There was no correlation between BMI and CTDIvol (r2 ≤ - 0.1 to 0.1, p = 0.931). Our study demonstrates up to ten-fold variability in ICM injection protocols and radiation doses across different CT protocols. The study emphasizes the need for optimizing CT scanning and contrast protocols to reduce unnecessary contrast and radiation exposure to patients. The wide variability and lack of standardization of ICM media and radiation doses in CT protocols suggest the need for education and optimization of contrast usage and scan factors for optimizing image quality in CECT. There is a lack of patient-centric CT protocol optimization taking into consideration mainly patients' size. There is a lack of correlation between ICM volume and CT radiation dose across CT protocol. A ten-fold variation in iodine-load for the same CT protocol in sites suggests a lack of standardization.

Effect of hyaluronic acid-based viscosupplementation on cartilage material properties

Viscosupplementation by intra-articular injections of hyaluronic acid (HA) is used to treat symptomatic osteoarthritis. Exogenous HA remains in the joint cavity for a short period of time (days) while claimed pain relief period lasts over months. There is a clear lack of understanding of viscosupplementation mechanism of action. Here, we hypothesize that HA penetrates the cartilage and contributes to the restoration of its mechanical quality.Confocal microscopy and bio-indentation were used to confirm HA penetration into cartilage and modulation of cartilage quality. Bio-indentation was performed on rat distal femurs incubated overnight in HA solutions, using phosphate buffered saline (PBS) as control. For this proof-of-concept evaluation, measurements of elastic modulus (MPa) and of maximal force (µN) were recorded before and immediately after exposure with HA, as well as after an additional washout with PBS. Cartilage thickness at the site of indentation was evaluated by contrast enhanced computed tomography with an ionic contrast agent. Indentation depths were located in the upper part of hyaline cartilage. Ostenil®, commercial product containing 1 % HA, induced a decrease in indentation depth in the range of forces influencing the whole cartilage thickness, together with an increase of the elastic modulus. Then, bio-indentation and size distribution of HA chains via SEC-SLS were assessed for a range of commercially available products. The results showed higher modulation of cartilage quality in the presence of 0.25–1 MDa HA chains.The present in vitro study suggests that HA modulates cartilage quality and might thus explain the long-term beneficial effect of viscosupplementation.

Influence of contrast medium on long-term renal function and outcomes in patients with septic acute kidney injury: A propensity-matched cohort study

PurposeTo investigate the relationship between contrast medium administration and long-term mortality and renal function in patients with septic acute kidney injury (AKI). Materials and methodsWe performed a retrospective, propensity-matched cohort study involving 1521 adult patients admitted with septic shock. Patients with septic AKI who underwent contrast or non-contrast CT scans were enrolled. The primary outcomes were the rates of 90-day mortality and dialysis within 90 days. The secondary outcomes included worsening of AKI, in-hospital mortality, and maintenance of dialysis after 90 days. ResultsDuring the study period, 609 patients with septic AKI were identified; 220 (36.1%) underwent contrast CT and 389 (63.9%) underwent non-contrast CT. After propensity score matching, 133 pairs were obtained. There were no significant differences between the contrast and non-contrast CT groups in 90-day mortality (54.9% vs. 58.6%, P = 0.579), dialysis within 90 days (6.8% vs. 8.3%, P = 0.655), worsening AKI (2.3% vs. 3.0%, P = 0.706), in-hospital mortality (10.6% vs. 14.4%, P = 0.369), or maintenance of dialysis after 90 days (0.0% vs. 0.8%, P > 0.99). ConclusionsThe administration of intravenous contrast medium was not associated with long-term mortality, deterioration of renal function, or dialysis in patients with septic AKI.

Additional use of extrinsic warmer for intravenous CT contrast media and its impact on incidence of contrast extravasations and allergic like reactions: a prospective observational case control study

To prospectively determine whether extrinsic warming of the low-osmolality CT contrast media (Iohexol 350, Iodixanol 320, Iopromide 300, and Iopamidol 300) to 37°C prior to intravenous administration affects extravasation and allergic-like reaction rates. This large scale prospective case control study of adverse events included all the patients between the age group of 15-80 years undergoing routine contrast-enhanced computed tomographic (CECT) examinations from April 2018 to March 2020 at our institute. Exvivo experiments were also performed to demonstrate change in contrast viscosity and fluid dynamics in relation to temperature. A total of 24,379 CECTs were conducted during the study period. Extrinsic warming showed a significant decrease in extravasation rates for Iohexol 350 at flow rates <3.5 mL/sec (P=0.037). No significant difference was observed with Iopromide 300 (P=0.432). Overall, a significant decrease in allergic reactions and overall contrast-related reactions (excluding physiologic reactions) was noted (P<0.001), with Iohexol 350. However, no significant difference was found with Iopromide 300. The most common physiological reaction was a sense of warmth, more prevalent in the warmed group, aligning with ex-vivo experiments demonstrating decreased viscosity with contrast warming. Extrinsic warming of contrast helps reduce the incidence of allergic-like reactions and extravasations for Iohexol 350, but no significant difference was noted with Iopromide 300 even at low injection rates (<3.5 mL/sec).

Reproducibility of a single-volume dynamic CT myocardial blood flow measurement technique: validation in a swine model

BackgroundWe prospectively assessed the reproducibility of a novel low-dose single-volume dynamic computed tomography (CT) myocardial blood flow measurement technique.MethodsThirty-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.ResultsThe 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.ConclusionThe 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.Relevance statementThe 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.Key PointsA 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.Graphical

Reducing Intravenous Contrast Utilization for CT: A Health System–Wide Intervention With Sustained Impact

ObjectiveTo determine the volume of intravenous iodinated contrast media used for CT before, during, and after the global iohexol shortage over a total of 17 months at a multisite health system. MethodsThis retrospective study included all patients who underwent CT at a large health system with 12 sites. Standardized contrast doses for 13 CT examinations were implemented May 23, 2022. Mean contrast utilization per CT encounter was compared between three periods (preintervention: January 1, 2022, to May 22, 2022; intervention: May 23, 2022, to September 11, 2022; postintervention: September 12, 2022, to June 30, 2023). Contrast doses and CT encounter data were extracted from the enterprise data warehouse. Categorical variables were compared with a χ2 test, and continuous variables were compared with a two-tailed t test. Multivariable linear regression assessed significance, with coefficients noted to determine magnitude and direction of effect. ResultsPreintervention, there were 152,009 examinations (87,722 with contrast [57.7%]); during the intervention, there were 120,031 examinations (63,217 with contrast [52.7%]); and during the postintervention, there were 341,862 examinations (194,231 with contrast [56.8%]). Preintervention, mean contrast dose was 89.3 mL per examination, which decreased to 78.0 mL after standardization (Δ of −12.7%) (P < .001). This decrease continued throughout the intervention and persisted in the postintervention period (80.4 mL; Δ −10.0%, P < .001). On multivariable analysis, patient weight, sex, and performing site were all associated with variations in contrast dose. Most but not all sites (9 of 12) sustained the decreased contrast media dose in the postintervention period. DiscussionImplementing standardized contrast media dosing for commonly performed CT examinations led to a rapid decrease in contrast media utilization, which persisted over 1 year.

Phase retrieval in propagation-based X-ray imaging beyond the limits of transport of intensity and contrast transfer function approaches.

We derive a phase retrieval formula for propagation-based phase contrast X-ray imaging that does not require weakly attenuating objects or short propagation distances. It is directly applicable to both single- and multiple-distance scenarios. We show the validity conditions and study the error of the underlying mutual intensity approximation, which uses the common assumptions of weak phase shift variations and phase-attenuation duality. The approximation generalizes those behind the transport of intensity (TIE) and contrast transfer function (CTF) models, and it approaches them when their respective additional assumptions are satisfied. When they are not, it clearly outperforms them, which we show both theoretically and practically on synthetic and measured data.