Contrast Dose Research Articles

Artificial Intelligence-Based Prediction of Contrast Medium Doses for Computed Tomography Angiography Using Optimized Clinical Parameter Sets.

In this paper, an artificial intelligence-based algorithm for predicting the optimal contrast medium dose for computed tomography (CT) angiography of the aorta is presented and evaluated in a clinical study. The prediction of the contrast dose reduction is modelled as a classification problem using the image contrast as the main feature. This classification is performed by random decision forests (RDF) and k-nearest-neighbor methods (KNN). For the selection of optimal parameter subsets all possible combinations of the 22 clinical parameters (age, blood pressure, etc.) are considered using the classification accuracy and precision of the KNN classifier and RDF as quality criteria. Subsequently, the results of the evaluation were optimized by means of feature transformation using regression neural networks (RNN). These were used for a direct classification based on regressed Hounsfield units as well as preprocessing for a subsequent KNN classification. For feature selection, an RDF model achieved the highest accuracy of 84.42% and a KNN model achieved the best precision of 86.21%. The most important parameters include age, height, and hemoglobin. The feature transformation using an RNN considerably exceeded these values with an accuracy of 90.00% and a precision of 97.62% using all 22 parameters as input. However, also the feasibility of the parameter sets in routine clinical practice has to be considered, because some of the 22 parameters are not measured in routine clinical practice and additional measurement time of 15 to 20 minutes per patient is needed. Using the standard feature set available in clinical routine the best accuracy of 86.67% and precision of 93.18% was achieved by the RNN. We developed a reliable hybrid system that helps radiologists determine the optimal contrast dose for CT angiography based on patient-specific parameters.

Image quality of photon-counting detector CT virtual monoenergetic and polyenergetic reconstructions for head and neck CT angiography

We compared image quality of head and neck CT angiography (CTA) obtained with a photon-counting detector CT (PCD-CT), including virtual monoenergetic images and polyenergetic reconstructions, and conventional energy-integrating detectors CT (EID-CT) in three patients. PCD-CT monoenergetic reconstructions at 70 keV and lower provided excellent image quality, with improved signal-to-noise and contrast-to-noise compared to EID-CT and PCD-CT polyenergetic reconstructions. PCD-CT may enable radiation dose and iodinated contrast dose reduction for cerebrovascular imaging.

Patient characteristics associated with acute kidney injury following coronary angiography

Objective The objective of this study was to identify patient characteristics associated with acute kidney injury (AKI) post-coronary angiography with or without percutaneous coronary intervention. Methods This retrospective, single-center study analyzed 350 patients from October 1, 2017 to September 30, 2018. The primary endpoint was AKI, defined as a rise in creatinine >0.3 mg/dL within 48 hours of coronary angiography. Results AKI occurred in 41 of 350 patients (8.8%). Patients experiencing AKI had a higher incidence of hypertension (100%; P = 0.005), hyperlipidemia (98%; P = 0.001), diabetes mellitus (68%; P = 0.0005), and heart failure (37%; P = 0.0057). AKI occurred in 30 of 185 (16%) and 11 of 165 (6.7%) patients undergoing femoral and radial access, respectively. AKI incidence was not significantly affected by contrast dose (99 ± 9 vs 93 ± 3 mL; P = 0.52), fluoroscopy time (10.3 min [IQR 6.3, 17.7] vs 8.5 min [IQR 4.5, 13.9]; P = 0.2), or preprocedural computed tomography with contrast (P = 0.66). Multivariable regression showed significantly higher AKI among patients with peripheral artery disease (odds ratio [OR] = 12.4; 95% confidence interval [CI] 3.4–33.6; P = 0.0001), multivessel coronary artery disease (OR = 11.9; 95% CI 2.3–61.1; P = 0.003), and initial creatinine >1.5 mg/dL (OR = 4.4; 95% CI 1.4–13.6; P = 0.01). Conclusion Peripheral artery disease, multivessel disease, and creatinine >1.5 mg/dL were associated with a higher risk of AKI in patients undergoing coronary angiography in this single-center retrospective cohort.

CMR 3-85 - Reducing the Contrast Dose by 80% in Quantitative Perfusion CMR Enabled by Patch-wise Deep Learning

CMR 3-85 - Reducing the Contrast Dose by 80% in Quantitative Perfusion CMR Enabled by Patch-wise Deep Learning

Risk factor analyses of contrast leakage and contrast-induced encephalopathy following coil embolization for unruptured intracranial aneurysm

BackgroundContrast-induced encephalopathy (CIE) following endovascular interventions is a rare but serious complication. This study aimed to investigate the risk factors of contrast leakage (CL) and CIE in patients who underwent...

Benefits of low-dose carotid CT angiography in stroke patients

Introduction: Computed tomography angiography (CTA) represents the gold standard as a method for the diagnosis of carotid artery diseases. The current topic is the use of CTA for the evaluation of carotid arteries with a reduction in the dose of contrast agent and dose of ionizing radiation, which, with adequate preparation, would enable the use of this method in some risk groups. The aim of this study was to evaluate the feasibility and image quality of a new low-dose CTA protocol in comparison with a standard protocol. Methods: Forty patients with recumbent ischemic stroke were included in the study, twenty of whom underwent lowdose CTA, and the remaining twenty underwent a standard CTA protocol of the carotid arteries. Results: No significant difference was found between the mean values of CT number (Hounsfield unit), signal-to-noise ratio, contrast-to-noise ratio, and subjective assessment of image quality in the comparison of the control and experimental groups. CT dose index, volume, and dose length product were significantly lower in patients who underwent lowdose carotid CTA. There was no significant difference in the degree of carotid stenosis between color Doppler and CTA. Conclusion: The use of the low-dose protocol for carotid CTA allows the application of this method in risk groups, in which it was previously not possible to perform, with the same image quality in comparison with the standard protocol.

Quantifying iodine concentration in the normal bowel wall using dual-energy CT: influence of patient and contrast characteristics

This study aimed to establish quantitative references of the normal bowel wall iodine concentration (BWIC) using dual energy CT (DECT). This single-center retrospective study included 248 patients with no history of gastrointestinal disease who underwent abdominal contrast-enhanced DECT between January and April 2022. The BWIC was normalized by the iodine concentration of upper abdominal organs (BWICorgan,) and the iodine concentration (IC) of the aorta (BWICaorta). BWIC decreased from the stomach to the rectum (mean 2.16 ± 0.63 vs. 2.19 ± 0.63 vs. 2.1 ± 0.58 vs. 1.67 ± 0.47 vs. 1.31 ± 0.4 vs. 1.18 ± 0.34 vs. 0.94 ± 0.26 mgI/mL for the stomach, duodenum, jejunum, ileum, right colon, left colon and rectum, respectively; P < 0.001). By multivariate analysis, BWIC was associated with a higher BMI (OR:1.01, 95% CI 1.00–1.02, P < 0.001) and with a higher injected contrast dose (OR: 1.51; 95% CI 1.36–1.66, P < 0.001 and 2.06; 95% CI 1.88–2.26, P < 0.001 for 500 mgI/kg and 600 mgI/kg doses taking 400 mgI/kg dose as reference). The BWICorgan was shown independent from patients and contrast-related variables while the BWICaorta was not. BWIC varies according to bowel segments and is dependent on the total iodine dose injected. It shall be normalized with the IC of the upper abdominal organs.

Advantages of Photon-Counting Detector CT in Aortic Imaging.

Photon-counting Computed Tomography (PCCT) is a promising imaging technique. Using detectors that count the number and energy of photons in multiple bins, PCCT offers several advantages over conventional CT, including a higher image quality, reduced contrast agent volume, radiation doses, and artifacts. Although PCCT is well established for cardiac imaging in assessing coronary artery disease, its application in aortic imaging remains limited. This review summarizes the available literature and provides an overview of the current use of PCCT for the diagnosis of aortic imaging, focusing mainly on endoleaks detection and characterization after endovascular aneurysm repair (EVAR), contrast dose volume, and radiation exposure reduction, particularly in patients with chronic kidney disease and in those requiring follow-up CT.

The impact of water exchange on estimates of myocardial extracellular volume calculated using contrast enhanced T1 measurements: A preliminary analysis in patients with severe aortic stenosis.

Guidelines recommend measuring myocardial extracellular volume (ECV) using T1 -mapping before and 10-30 min after contrast agent administration. Data are then analyzed using a linear model (LM), which assumes fast water exchange (WX) between the ECV and cardiomyocytes. We investigated whether limited WX influences ECV measurements in patients with severe aortic stenosis (AS). Twenty-five patients with severe AS and 5 healthy controls were recruited. T1 measurements were made on a 3 T Siemens system using a multiparametric saturation-recovery single-shot acquisition (a) before contrast; (b) 4 min post 0.05 mmol/kg gadobutrol; and (c) 4 min, (d) 10 min, and (e) 30 min after an additional gadobutrol dose (0.1 mmol/kg). Three LM-based ECV estimates, made using paired T1 measurements (a and b), (a and d), and (a and e), were compared to ECV estimates made using all 5 T1 measurements and a two-site exchange model (2SXM) accounting for WX. Median (range) ECV estimated using the 2SXM model was 25% (21%-39%) for patients and 26% (22%-29%) for controls. ECV estimated in patients using the LM at 10 min following a cumulative contrast dose of 0.15 mmol/kg was 21% (17%-32%) and increased significantly to 22% (19%-35%) at 30 min (p = 0.0001). ECV estimated using the LM was highest following low dose gadobutrol, 25% (19%-38%). Current guidelines on contrast agent dose for ECV measurements may lead to underestimated ECV in patients with severe AS because of limited WX. Use of a lower contrast agent dose may mitigate this effect.

Role of MDCTA in Bronchial Artery Embolization in patients with Hemoptysis

Objective:To evaluate the role of bronchial artery MDCTA in bronchial artery embolization in the treatment of haemoptysis patients. Methods: 46 patients treated with bronchial artery embolization for haemoptysis was included in the study at 1st Affiliated Hospital, Jinzhou Medical University. They were classified into 2 groups, Group A-Preoperative CTA and Group B -Simple DSA. Group A (n=28) is those with preoperative CTA examination performed, while group B (n=18) is those who performed DSA directly without preoperative CTA. The results of CTA and DSA, technical and clinical outcome compared and analyzed. Results: 48 bleeding arteries were identified in group A while 24 bleeding arteries were identified in group B. These arteries were embolized successfully. In the group A total fluoroscopy time, total operative time, and contrast dose were shorter than group B respectively (8.42± 2.82; 28.34± 5.61; 27.86± 6.42 VS. 18.46± 10.34; 40.27±16.32; 62.59±19.48). Conclusion: Bronchial artery CTA can objectively evaluate haemoptysis associated with vascular origin, number and its shape and it can reduce the operative time and reduce the radiation exposure to doctors and patients too, it increase the success rate of haemoptysis interventional therapy guidance has wide clinical application value

Coronary CT angiography a new promising tool in Heart transplanted patients: from clinical and economical benefits to coronary inflammation detection

Abstract Background Heart transplanted patients are usually monitored with invasive diagnostic techniques for detecting cardiac allograft vasculopathy (CAV). However coronary CT angiography (CCTA) is a new promising tool in the initial stages of CAV bringing clinical and economical benefits. Purpose 1) assess the non-inferiority of CCTA in comparison to coronary angiography (CA), in terms of radiation and contrast dose, costs, hospitalization hours, complications and diagnostic accuracy; 2) analyse the different role of immunological and non-immunological risk factors predicting CAV in patients undergoing CCTA; 3) Investigate the rule of coronary inflammation through the pericoronary-fat-attenuation-index (pFAI) at CCTA in the progression of CAV. Methods 179 heart transplanted patients were retrospectively analysed: 78 performed a CCTA and 101 performed a CA between March 2021 and May 2022. Results CCTA and CA showed similar radiation doses (8.47 [1.46-30] versus 8.15 [1.38-87.34]; p=0.796) and rate of complications (0 (0%) vs 3 (3%); p=0,258). CCTA in comparison with CA required less hours of hospitalization (0.5 hours versus 23.7 12.31 hours; p&amp;lt;0.001), lower costs (120 euros versus 2800 euros; p&amp;lt;0.001) and less contrast agent (60.4 8.7 ml versus 95.68 47.6ml; p&amp;lt;0.001). Diagnostic accuracy was similar between CCTA and CA (95% vs 100%; p=0,169). Among the non immunological risk factors for CAV, only smoking showed a statistically significance in predicting CAV (p=0.015). Among immunological risk factors, TNF was the only independent predictor in the progression of CAV (HR 8.23; IC 95% 1.47-45.81; p=0.019). There were no statistically correlation between pFAI at CCTA either as a continuous variable or as a categorical variable (&amp;gt;-70.1HU) and the progression of CAV (p=NS). Conclusions CCTA is similar to CA in terms of radiation dose and rate of complications and is superior in terms of hospitalization hours, costs and contrast agent injected. Diagnostic accurancy was equivalent between CCTA and CA. TNF was the only independent predictor in the progression of CAV. Pericoronary inflammation assessed by pFAI at CCTA was not associated with the progression of CAV.

Impact of SGLT2-inhibitors on contrast-induced acute kidney injury in diabetic patients with acute myocardial infarction: data from SGLT2-I AMI PROTECT Registry

Abstract Background Diabetes patients presenting with acute myocardial infarction (AMI) undergoing primary percutaneous coronary intervention (PCI) have an increased risk of contrast induced-acute kidney injury (CI-AKI). It has been shown that SGLT2-I have a nephroprotective effect. Purpose To analyze the association between SGLT2-I treatment and the development of contrast-induced acute kidney injury (CI-AKI) in diabetic patients with AMI (both ST- and non-ST segment elevation myocardial infarction - STEMI and NSTEMI) treated with PCI. Methods In this multicenter international registry, all consecutive diabetic AMI patients undergoing PCI between 2018 and 2021 were enrolled. Based on the admission anti-diabetic therapy, they were divided into SGLT-I users versus non-SGLT2-I users. All patients had estimated glomerular filtration rate (eGFR) of &amp;gt;30 mL/min/1.73 m2. No patient discontinued SGLT2-I during hospitalization. Serum creatinine was collected at admission and within 72 h post-PCI. CI-AKI was defined as absolute (≥0.5 mg/dl) or relative increase (≥25%) in serum creatinine at 48-72 h after PCI compared to baseline serum creatinine values. Results The study population consisted of 646 AMI patients: 111 SGLT2-I users and 535 non-SGLT-I users. The mean age of the overall study population was 70 [61-79] years, and more than 77% were males. The mean T2DM duration was similar for both groups. SGLT2-I patients were younger and with better renal function at admission compared to non-SGLT2-I users (p&amp;lt;0.018 for both). Gender, cardiovascular risk factors, glucose-metabolic control, and comorbidities were similar in the two groups. The rate of STEMI and the main angiographic characteristics were similar between the two study groups, except for the higher number of stents implanted in the SGLT2-I group (p=0.041). Vascular access and contrast dosage did not differ between the 2 cohorts. A similar rate of complete revascularization, staged procedure and complex PCI was observed between the study groups. After PCI, the overall rate of CI-AKI was 76 (11.8%). SGLT2-I users exhibit a lower rate of CI-AKI compared to non-SGLT-I ones (5.4% vs 13.1%, p=0.02), with significantly lower creatinine values both after PCI (p=0.016) and at discharge (p=0.046). At multivariate analysis, after adjusting for all confounding factors, the use of SGLT2-I was identified as independent predictor of reduced rate of CI-AKI (OR 0.374; 95% CI 0.142-0.987, p=0.040). During a median follow-up of 24±13 months, patients with CI-AKI showed a higher incidence of MACE compared to patients without (44.7% vs 25.8%, p=0.001). Conclusion In diabetic patients with AMI, the use of SGLT2-I was associated with a lower risk of CI-AKI during index hospitalization, providing new insights into the cardioprotective effects of SGLT2-I in the setting of AMI.

Sonothrombolysis with microbolus administration of perfluoropropane as point of care therapy for STEMI patients

Abstract Introduction There are still major obstacles to timely revascularisation of STEMI patients even on arrival to PCI capable centers. Delivery of intermittent high mechanical index(MI) pulses during contrast infusion(Sonothrombolysis) has been shown to improve culprit vessel recanalization rates, reduce infarct size and improve myocardial hemodynamics. Purpose Our objective was to see if sonothrombolysis administered with a low dose of echo contrast(2mL) given as successive microboluses resulted in angiographic recanalisation. This is pertinent in our resource limited setup as continuous infusion needs specialised pumps and cost of echo contrast is high. Methods This was a randomised control trial on 100 patients presenting with first STEMI (within a window period of 12 hours, Killips stage I or II) to the Chest Pain Unit(CPU) of our institution. The intervention was sonothrombolysis during successive microboluses of perfluoropropane followed by PPCI. Technique of Sonothombolysis: 1 vial of perfluoropropane(2mL) is agitated and diluted in 20ML normal saline(0.1%w/v). Using a 3 way stop cock, 2mL solution is given while performing echocardiography in standard views. This leads to good chamber opacification for 40-60 beats. Once chamber opacification is adequately achieved (usually within 10 beats), high MI pulses (&amp;gt;1.1 MI) were given repeatedly after low MI imaging shows replenishment of microbubbles in the myocardial segment. Once opacification wanes, then another bolus of 2mL is given and steps repeated. The control group underwent low MI imaging with 0.2mL of perfluoropropane followed by PPCI. Results The trial was halted after recruitment of 57 patients following an interim analysis which showed no significant benefit with sonothrombolysis. Angiographic recanalization of culprit vessel occured in 28% of cases (8vs6, p=0.589). Baseline characteristics were similar across both groups. The time from first medical contact(FMC) to balloon time were similar. The use of Gp IIb/IIIa inhibitors or thrombus aspiration catheters did not differ. Discussion Sonothrombolysis with successive microboluses of perflouropropane is not effective in producing angiographic recanalization in STEMI patients. Our results vary from that of Mathias et al which showed a 48% angiographic recanalization rate. The protocol of giving microboluses as against continuous infusion could have contributed though we looked specifically for microbubble replenishment in myocardial segments before delivering high MI pulses. Secondly the higher prevalence of diabetes, dyslipidemia and multivessel CAD in our population could have contributed to the lack of efficacy. Thirdly the mean window period (time between onset of symptoms to arrival at CPU) was 7±2.31hrs which could have contributed to thrombus organization and resistance to shearing forces produced by microbubble cavitation. Further randomized studies are needed to see the efficacy of sonothrombolysis in other populations.Table 1.Baseline CharacteristicsTable 2.Results

Reducing Gadolinium Contrast With Artificial Intelligence.

Gadolinium contrast is an important agent in magnetic resonance imaging (MRI), particularly in neuroimaging where it can help identify blood-brain barrier breakdown from an inflammatory, infectious, or neoplastic process. However, gadolinium contrast has several drawbacks, including nephrogenic systemic fibrosis, gadolinium deposition in the brain and bones, and allergic-like reactions. As computer hardware and technology continues to evolve, machine learning has become a possible solution for eliminating or reducing the dose of gadolinium contrast. This review summarizes the clinical uses of gadolinium contrast, the risks of gadolinium contrast, and state-of-the-art machine learning methods that have been applied to reduce or eliminate gadolinium contrast administration, as well as their current limitations, with a focus on neuroimaging applications. EVIDENCE LEVEL: 3 TECHNICAL EFFICACY: Stage 1.

Simultaneous quantification of perfusion, permeability, and leakage effects in brain gliomas using dynamic spin-and-gradient-echo echoplanar imaging MRI

ObjectiveTo determine the feasibility and biologic correlations of dynamic susceptibility contrast (DSC), dynamic contrast enhanced (DCE), and quantitative maps derived from contrast leakage effects obtained simultaneously in gliomas using dynamic spin-and-gradient-echo echoplanar imaging (dynamic SAGE-EPI) during a single contrast injection.Materials and methodsThirty-eight patients with enhancing brain gliomas were prospectively imaged with dynamic SAGE-EPI, which was processed to compute traditional DSC metrics (normalized relative cerebral blood flow [nrCBV], percentage of signal recovery [PSR]), DCE metrics (volume transfer constant [Ktrans], extravascular compartment [ve]), and leakage effect metrics: ΔR2,ss* (reflecting T2*-leakage effects), ΔR1,ss (reflecting T1-leakage effects), and the transverse relaxivity at tracer equilibrium (TRATE, reflecting the balance between ΔR2,ss* and ΔR1,ss). These metrics were compared between patient subgroups (treatment-naïve [TN] vs recurrent [R]) and biological features (IDH status, Ki67 expression).ResultsIn IDH wild-type gliomas (IDHwt—i.e., glioblastomas), previous exposure to treatment determined lower TRATE (p = 0.002), as well as higher PSR (p = 0.006), Ktrans (p = 0.17), ΔR1,ss (p = 0.035), ve (p = 0.006), and ADC (p = 0.016). In IDH-mutant gliomas (IDHm), previous treatment determined higher Ktrans and ΔR1,ss (p = 0.026). In TN-gliomas, dynamic SAGE-EPI metrics tended to be influenced by IDH status (p ranging 0.09–0.14). TRATE values above 142 mM−1s−1 were exclusively seen in TN-IDHwt, and, in TN-gliomas, this cutoff had 89% sensitivity and 80% specificity as a predictor of Ki67 > 10%.ConclusionsDynamic SAGE-EPI enables simultaneous quantification of brain tumor perfusion and permeability, as well as mapping of novel metrics related to cytoarchitecture (TRATE) and blood–brain barrier disruption (ΔR1,ss), with a single contrast injection.Clinical relevance statementSimultaneous DSC and DCE analysis with dynamic SAGE-EPI reduces scanning time and contrast dose, respectively alleviating concerns about imaging protocol length and gadolinium adverse effects and accumulation, while providing novel leakage effect metrics reflecting blood–brain barrier disruption and tumor tissue cytoarchitecture.Key Points• Traditionally, perfusion and permeability imaging for brain tumors requires two separate contrast injections and acquisitions.• Dynamic spin-and-gradient-echo echoplanar imaging enables simultaneous perfusion and permeability imaging.• Dynamic spin-and-gradient-echo echoplanar imaging provides new image contrasts reflecting blood–brain barrier disruption and cytoarchitecture characteristics.Graphical

Intraoperative angiography in neurosurgery: temporal trend, access site, and operative indication considerations from a 6-year institutional experience.

Historically, the transfemoral approach (TFA) has been the most common access site for cerebral intraoperative angiography (IOA). However, in line with trends in cardiac interventional vascular access preferences, the transradial approach (TRA) and transulnar approach (TUA) have been gaining popularity owing to favorable safety and patient satisfaction outcomes. To compare the efficacy and safety of TRA/TUA and TFA for cerebral and spinal IOA at an institutional level over a 6-year period. Between July 2016 and December 2022, 317 angiograms were included in our analysis, comprising 60 TRA, 10 TUA, 243 TFA, and 4 transpopliteal approach cases. Fluoroscopy time, contrast dose, reference air kerma, and dose-area products per target vessel catheterized were primary endpoints. Multivariate regression analyses were conducted to evaluate predictors of elevated contrast dose and radiation exposure and to assess time trends in access site selection. Contrast dose and radiation exposure metrics per vessel catheterized were not significantly different between access site groups when controlling for patient position, operative region, 3D rotational angiography use, and different operators. Access site was not a significant independent predictor of elevated radiation exposure or contrast dose. There was a significant relationship between case number and operative indication over the study period (P<0.001), with a decrease in the proportion of cases for aneurysm treatment offset by increases in total cases for the management of arteriovenous malformation, AVF, and moyamoya disease. TRA and TUA are safe and effective access site options for neurointerventional procedures that are increasingly used for IOA.

Brand ferumoxytol vs. generic ferumoxytol comparison across two dosing regimens: a cardiac MRI image quality study.

Ferumoxytol is becoming more widely used as an off-label blood-pool contrast agent for MR angiography (MRA) and four-dimensional (4D) flow imaging in pediatric cardiovascular disease. Brand and generic versions of ferumoxytol are available with no information on relative efficacy as a contrast agent and safety profiles. This study evaluates patient safety and image quality of comparable dosages of generic ferumoxytol (GF) versus brand ferumoxytol (BF) with the following hypotheses: (1) Reducing the contrast dosage from 3 to 2mg/kg will not affect imaging quality and diagnostic accuracy of MRA and four-dimensional 4D flow. (2) GF and BF have similar image quality. (3) GF and BF have similar patient safety profiles. In an IRB-approved retrospective study, changes in vitals/clinical status between baseline, during infusion, and 30min post-infusion were analyzed in 3 groups: group 1 (3mg/kg BF, 216 patients, age: 19.29 ± 11.71years ranging from 2months to 62years), group 2 (2mg/kg BF, 47 patients, age: 15.35 ± 8.56years ranging from 10days to 41years), and group 3 (2mg/kg GF, 127 patients, age: 17.16 ± 12.18years ranging from 6days to 58years). Both pediatric and adult patients with congenital heart disease (CHD) indications were included within the study. Adverse reactions were classified as mild, moderate, or severe. Quantitative analysis of MR image quality was performed with signal-to-noise ratio (SNR) on MRA and velocity-to-noise ratio (VNR) on 4D flow. Qualitative grading of imaging features was performed by 2 experienced observers. Two-way analysis of variance (ANOVA) and chi-square tests were used for comparison with a P value of ≤ 0.05 used for significance. No statistical difference was found in clinical status and vital signs (P>0.05). No severe reactions were reported. 7.9% of GF patients experienced an adverse reaction compared to 2.3% with 3mg/kg BF and 8.4% with 2mg/kg BF. There was no statistical difference in SNR between the 3 groups (P>0.05). For 4D flow, 2mg/kg GF demonstrated an increase in VNR compared to 2mg/kg BF (P = 0.005). The qualitative scores for MRA and 4D flow were high (≥ 3) across all 3 groups. No significant difference was identified between 2mg/kg GF and BF in terms of safety profile and image quality. Given the small sample size of this study, further studies are required to confirm these results.

The CT derived angle between the transseptal puncture site and the left atrial appendage as a predictor for complex interventional occlusion procedures.

To evaluate the role of the CT-derived angle between the intra-atrial septum (IAS) and the left atrial appendage (LAA) on procedural complexity and clinical outcomes in left atrial appendage occlusion (LAAO) procedures. Given the broad variations in anatomy, LAAO remains one of the most challenging interventional procedures in structural heart disease. In recent years, preprocedural cardiac tomography (CT) has evolved as a valuable tool; however, prediction of procedural complexity remains cumbersome. We retrospectively analyzed 47 patients that underwent LAAO at our center in whom pre-procedural cardiac CT-scans were available. Among other baseline parameters, we measured the angle between the LAA ostium and the preferred transseptal puncture site at the IAS. We compared patients with an angle above and below the median regarding procedural characteristics and procedural outcome. The median angle between the LAA and the IAS was 127.3° (IQR: 120.9-141.3). LAAO took longer in patients with a measured angle below the median (55.0±22.7min vs. 41.3±17.5min; p=.04), resulting in longer radiation times (13.0±5.3min vs. 9.8±5.7min; p=.04) and more contrast use (61.1±47.5mL vs. 33.6±24.7mL; p=.05). Moreover, the necessity for a sheath exchange was significantly higher (30.4%vs. 4.2%, p=.02) and device repositioning or device resizing trended to be more frequent (26.1%vs. 8.3%; p=.1 and 21.7%vs. 8.3%; p=.2). There were no differences in procedural outcome, device-position and peri-device leak (PDL). The angle between the transseptal puncture site and the LAA ostium may serve as a predictor for more demanding LAAO interventions. In our study a steeper angle led to a prolonged procedure resulting in higher doses of contrast and radiation, but was not associated with a worse procedural outcome.

Dual-layer spectral computed tomography aortography using a seventy-five-percent-reduced iodine dose protocol and multiparameter spectral imaging: comparison with conventional computed tomography imaging.

Computed tomography angiography (CTA) is the recommended diagnostic and follow-up imaging modality for acute aortic dissection (AD). However, the high-contrast medium burden associated with repeated CT aortography follow-ups remains a significant concern. This prospective study aimed to assess whether an ultra-low contrast dose (75% cutoff) aortic CTA protocol on dual-layer spectral CT could achieve comparable image quality with the full dose protocol. We also investigated the image quality of the virtual noncontrast (VNC) images derived from the ultra-low dose protocol. This study included 37 consecutive patients who were referred to aortic CTA from May 2022 to August 2022. The enrolled patients underwent full-dose contrast CTA and ultra-low dose (reduced to 25% of conventional) contrast CTA on dual-layer spectral CT in 1 day. Virtual monochromatic images (VMIs) were reconstructed with 40 and 70 keV. The VNC images were reconstructed for both protocols. Objective image quality evaluation, recorded as signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNRs), was compared between the groups using 1-way analysis of variance and post hoc analysis with Bonferroni correction. Subjective image quality was also compared between the groups. Finally, VNC images derived from the low-dose (VNClow) and full-dose (VNCfull) protocols were compared to the true noncontrast (TNC) images. Neither CNR nor SNR was lower for the 40-keV images reconstructed from the ultra-low dose group compared to the conventional images. Both were significantly higher than those of the 70-keV images. Regarding subjective image quality, vessel enhancement was not significantly different between the 40-keV VMI and full-dose images [ascending aorta (AAO): 4.37±0.46 vs. 4.57±0.48, P=0.096; brachiocephalic arteries: 4.34±0.45 vs. 4.51±0.49, P=0.152; abdominal aortic side branch: 4.42±0.48 vs. 4.51±0.49, P=0.480]. The VNClow images were similar to the TNC images but significantly different from the VNCfull images (P<0.001). Ultra-low contrast aortic CTA with a 75%-reduced iodine dose using dual-layer spectral CT and the derived VNC achieved image quality comparable to that of conventional CTA and TNC images.

Deep learning-based iodine contrast-augmenting algorithm for low-contrast-dose liver CT to assess hypovascular hepatic metastasis.

To investigate the image quality and diagnostic performance of low-contrast-dose liver CT using a deep learning-based iodine contrast-augmenting algorithm (DLICA) for hypovascular hepatic metastases. This retrospective study included 128 patients who underwent contrast-enhanced dual-energy CT for hepatic metastasis surveillance between July 2019 and June 2022 using a 30% reduced iodine contrast dose in the portal phase. Three image types were reconstructed: 50-keV virtual monoenergetic images (50-keV VMI); linearly blended images simulating 120-kVp images (120-kVp); and post-processed 120-kVp images using DLICA (DLICA 120-kVp). Three reviewers evaluated lesion conspicuity, image contrast, and subjective image noise. We also measured image noise, contrast-to-noise ratios (CNRs), and signal-to-noise ratios (SNRs). The diagnostic performance for hepatic metastases was evaluated using a jackknife alternative free-response receiver operating characteristic method with the consensus of two independent radiologists as the reference standard. DLICA 120-kVp demonstrated significantly higher CNR of lesions to liver (5.7±3.1 vs. 3.8±2.1 vs. 3.8±2.1) and higher SNR compared with 50-keV VMI and 120-kVp (p<0.001 for all). DLICA 120-kVp had significantly lower image noise than 50-kVp VMI for all regions (p<0.001 for all). DLICA 120-kVp also exhibited superior lesion conspicuity (4.0 [3.3-4.3] vs. 3.7 [3.0-4.0] vs. 3.7 [3.0-4.0]), higher image contrast, and lower subjective image noise compared with 50-keV VMI and 120-kVp (p<0.001 for all). Although there was no significant difference in the figure of merit for lesion diagnosis among the three methods (p=0.11), DLICA 120-kVp had a significantly higher figure of merit for lesions with a diameter <20 mm than 50-keV VMI (0.677 vs. 0.648, p=0.007). On a per-lesion basis, DLICA 120-kVp also demonstrated higher sensitivity than the 50-keV VMI (81.2% vs. 72.9%, p<0.001). The specificities per lesion were not significantly different among the three algorithms (p=0.15). DLICA at 120-kVp provided superior lesion conspicuity and image quality and similar diagnostic performance for hypovascular hepatic metastases compared with 50-keV VMI.